test(git-sync): accurate null-edge docstring + fill round placeholder (F2/F3)

F2: the real-git modify/delete null-edge test docstring overclaimed it
caught loss of the `?? theirs` fallback end-to-end. git itself leaves
theirs in the working tree (stage 3) so commitMerge's `git add -A` would
stage it even with the bug — the assertions pass on broken logic. Reword
to state it verifies the clean-merge happy path; the real F1 regression
guard lives in the fake-fs apply-pull-actions.test.ts.

F3: fill the `round-?` placeholder with `round-2` in both new blocks to
match the file convention (header: 'QA #119 round-2').

Comment-only; no production or test-logic changes.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.env.example

@@ -203,3 +203,42 @@ MCP_DOCMOST_PASSWORD=
 # FAILS CLOSED if Redis is unavailable (default: 1,000,000 tokens per workspace
 # per rolling day).
 # SHARE_AI_WORKSPACE_TOKEN_BUDGET_PER_DAY=1000000
+
+# --- GIT-SYNC (native two-way Docmost <-> git Markdown sync) ---
+# Master switch. Off by default. When 'true', GIT_SYNC_SERVICE_USER_ID below is
+# REQUIRED (the service account that git-originated create/move/rename/delete are
+# attributed to) — the server refuses to boot with sync enabled and no user id.
+# GIT_SYNC_ENABLED=false
+#
+# Serve the per-space vaults over smart-HTTP (the /git host). Defaults to
+# GIT_SYNC_ENABLED when unset.
+# GIT_SYNC_HTTP_ENABLED=false
+#
+# REQUIRED when GIT_SYNC_ENABLED=true: id of the user that git-originated page
+# operations (create / move / rename / delete) are attributed to.
+# GIT_SYNC_SERVICE_USER_ID=
+#
+# Where the per-space working vaults live (non-bare repos; the engine needs a
+# working tree).
+# Defaults to "<DATA_DIR or ./data>/git-sync".
+# GIT_SYNC_DATA_DIR=
+#
+# Optional remote URL template to mirror each space's vault to (e.g. a git host).
+# The literal "{spaceId}" is substituted per-space, so each space mirrors to its
+# OWN remote — e.g. git@host:vault-{spaceId}.git. Without the placeholder every
+# space would point at one remote. Leave unset to keep vaults local-only.
+# GIT_SYNC_REMOTE_TEMPLATE=
+#
+# Poll-safety interval in ms — the cadence of the background reconcile cycle
+# (default: 15000).
+# GIT_SYNC_POLL_INTERVAL_MS=15000
+#
+# Debounce window in ms for collapsing bursts of page edits into one sync cycle
+# (default: 2000).
+# GIT_SYNC_DEBOUNCE_MS=2000
+#
+# Watchdog timeout in ms for the spawned `git http-backend` process serving a
+# git smart-HTTP push (default: 120000). A stalled/hung receive-pack is killed
+# after this deadline so it cannot hold the per-space lock forever.
+# GIT_SYNC_BACKEND_TIMEOUT_MS=120000
+#

.github/workflows/test.yml

@@ -68,6 +68,13 @@ jobs:
       - name: Build editor-ext
         run: pnpm --filter @docmost/editor-ext build
 
+      # git-sync and mcp are no longer committed in built form (build/ is
+      # gitignored), so CI must compile them: the server resolves both via their
+      # built build/index.js. The server pretest also builds them, but building
+      # here keeps it explicit and independent of pnpm lifecycle ordering.
+      - name: Build git-sync and mcp
+        run: pnpm --filter @docmost/git-sync build && pnpm --filter @docmost/mcp build
+
       - name: Run unit tests
         run: pnpm -r test
 

.gitignore

@@ -5,6 +5,12 @@ data
 # compiled output
 /dist
 /node_modules
+# workspace package node_modules (pnpm symlinks — never commit; they bake
+# machine-local store paths) and the git-sync compiled output (built in CI/Docker
+# via `pnpm build`, never committed, so src/ and prod can never silently diverge).
+packages/*/node_modules/
+packages/git-sync/build/
+packages/mcp/build/
 
 # Logs
 logs

AGENTS.md

@@ -182,7 +182,7 @@ tea issues create --repo vvzvlad/gitmost --labels feature \
 
 ## Monorepo layout
 
-pnpm workspace (`pnpm@10.4.0`) orchestrated by **Nx**. Four workspace packages:
+pnpm workspace (`pnpm@10.4.0`) orchestrated by **Nx**. Five workspace packages:
 
 | Path | Name | Stack | Role |
 | --- | --- | --- | --- |
@@ -190,6 +190,7 @@ pnpm workspace (`pnpm@10.4.0`) orchestrated by **Nx**. Four workspace packages:
 | `apps/client` | `client` | React 18 + Vite + Mantine 8 + TanStack Query + Jotai | SPA frontend |
 | `packages/editor-ext` | `@docmost/editor-ext` | Tiptap/ProseMirror | Shared Tiptap node/mark extensions, imported by both the client and the server |
 | `packages/mcp` | `@docmost/mcp` | MCP SDK, Tiptap, Yjs | Standalone MCP server, also bundled into the server at `/mcp`. Does **not** import `editor-ext` — it keeps its own vendored mirror of the schema in `packages/mcp/src/lib/` |
+| `packages/git-sync` | `@docmost/git-sync` | Tiptap/ProseMirror, Yjs, git | Pure ProseMirror↔Markdown converter plus the two-way Docmost↔git Markdown sync engine. Bundled into the server (loaded over the ESM bridge), built in CI and the Dockerfile. Does **not** import `editor-ext` — it keeps its own vendored mirror of the document schema (kept in sync with `editor-ext`). |
 
 `build` targets are Nx-cached and dependency-ordered (`dependsOn: ["^build"]`), so `editor-ext` builds before the apps. `nx.json` sets `affected.defaultBase: main`.
 
@@ -243,8 +244,10 @@ Migration files live in `apps/server/src/database/migrations/` and are named `YY
 
 The API server is a Fastify app with a global `/api` prefix (`main.ts` excludes `robots.txt`, public share pages, and `mcp` from the prefix). A `preHandler` hook enforces that a resolved `workspaceId` exists for most `/api` routes (multi-tenant by hostname/subdomain via `DomainMiddleware`). Auth is JWT (cookie + bearer); authorization is **CASL** (`core/casl`) — every data access is scoped to the user's abilities.
 
+Two routes are mounted **outside** the `/api` prefix at the root, as raw Fastify routes that bypass the Nest pipeline (so neither `DomainMiddleware` nor `ThrottlerGuard` runs for them — each resolves the workspace and throttles itself): `/mcp` (the embedded MCP server, see below) and `/git/<spaceId>.git/...` (the git-sync smart-HTTP host, see below). Both share `mcp-auth.helpers.ts` (HTTP-Basic parsing, `FailedLoginLimiter`, `clientIp`) and the common `resolveRequestWorkspace` helper.
+
 ### Module structure (server)
-`AppModule` wires integration modules (`integrations/*`: storage [local/S3/Azure], mail, queue [BullMQ on Redis], security, telemetry, throttle, `mcp`, `ai`) plus `CoreModule`, `DatabaseModule`, and `CollaborationModule`. `CoreModule` (`core/*`) holds the domain modules: `page`, `space`, `comment`, `workspace`, `user`, `auth`, `group`, `attachment`, `search`, `share`, `ai-chat`, etc. Each domain module follows NestJS controller → service → repo layering; DB repos live under `database/repos` and are injected app-wide from the global `DatabaseModule`.
+`AppModule` wires integration modules (`integrations/*`: storage [local/S3/Azure], mail, queue [BullMQ on Redis], security, telemetry, throttle, `mcp`, `ai`, `git-sync`) plus `CoreModule`, `DatabaseModule`, and `CollaborationModule`. `CoreModule` (`core/*`) holds the domain modules: `page`, `space`, `comment`, `workspace`, `user`, `auth`, `group`, `attachment`, `search`, `share`, `ai-chat`, etc. Each domain module follows NestJS controller → service → repo layering; DB repos live under `database/repos` and are injected app-wide from the global `DatabaseModule`.
 
 **EE removal artifact:** `app.module.ts` still contains a `try/require('./ee/ee.module')` stub. That path no longer exists, so the require fails and is swallowed (it only hard-exits when `CLOUD === 'true'`). Treat EE as gone — do not add code that depends on it.
 
@@ -254,16 +257,22 @@ The API server is a Fastify app with a global `/api` prefix (`main.ts` excludes
 - **Redis** backs caching, the BullMQ queues, the WebSocket Socket.IO adapter, and collaboration sync.
 
 ### The two AI subsystems (the main fork additions)
-1. **Embedded MCP server** (`integrations/mcp/` + `packages/mcp`). The standalone `@docmost/mcp` server (38 agent-native tools: per-block patch/insert/delete by id, scripted `(doc)=>doc` transforms with dry-run diff, table editing, version diff/restore, comments, images, shares) is bundled and served over HTTP at `/mcp`. It writes through Docmost's real-time-collaboration layer so concurrent human edits aren't clobbered. Each request authenticates **per-user** via the `Authorization` header — either HTTP Basic (`base64(email:password)`, the user's own Docmost login, validated through `AuthService`) or a Bearer access JWT (the user's `authToken`) — and the session acts under that user's permissions. `MCP_DOCMOST_EMAIL` / `MCP_DOCMOST_PASSWORD` are an **optional service-account fallback**, used only when a request carries neither Basic nor Bearer credentials (back-compat for CI/scripts). An admin enables MCP with a workspace toggle (Workspace settings → AI). Optionally protected by a shared `MCP_TOKEN`: when set, every `/mcp` request must carry a matching `X-MCP-Token` header (its own header, separate from `Authorization`, which now carries the per-user Basic/Bearer credentials). Note: this changed from the older `Authorization: Bearer <MCP_TOKEN>` scheme — see `.env.example` and the CHANGELOG Breaking Changes entry.
+1. **Embedded MCP server** (`integrations/mcp/` + `packages/mcp`). The standalone `@docmost/mcp` server (39 agent-native tools: per-block patch/insert/delete by id, scripted `(doc)=>doc` transforms with dry-run diff, table editing, version diff/restore, comments, images, shares) is bundled and served over HTTP at `/mcp`. It writes through Docmost's real-time-collaboration layer so concurrent human edits aren't clobbered. Each request authenticates **per-user** via the `Authorization` header — either HTTP Basic (`base64(email:password)`, the user's own Docmost login, validated through `AuthService`) or a Bearer access JWT (the user's `authToken`) — and the session acts under that user's permissions. `MCP_DOCMOST_EMAIL` / `MCP_DOCMOST_PASSWORD` are an **optional service-account fallback**, used only when a request carries neither Basic nor Bearer credentials (back-compat for CI/scripts). An admin enables MCP with a workspace toggle (Workspace settings → AI). Optionally protected by a shared `MCP_TOKEN`: when set, every `/mcp` request must carry a matching `X-MCP-Token` header (its own header, separate from `Authorization`, which now carries the per-user Basic/Bearer credentials). Note: this changed from the older `Authorization: Bearer <MCP_TOKEN>` scheme — see `.env.example` and the CHANGELOG Breaking Changes entry.
 2. **AI agent chat** (`core/ai-chat/` server + `apps/client/src/features/ai-chat/` client). A built-in agent over the wiki using the Vercel **AI SDK** (`ai`, `@ai-sdk/*`) against any OpenAI-compatible provider configured per workspace (`integrations/ai/` — credentials encrypted at rest via `integrations/crypto`, stored in `ai_provider_credentials`). Key pieces:
    - `core/ai-chat/tools/` — the agent's ~40 read+write tools. Every tool runs under the **calling user's** CASL permissions via a per-user loopback access token (`docmost-client.loader.ts`), so the agent can never exceed what the user could do. Only **reversible** operations are exposed (page history + trash; no permanent delete). Agent edits get an "AI agent" provenance badge in page history (`20260616T130000-agent-provenance` migration).
    - `core/ai-chat/embedding/` — RAG indexer + a BullMQ consumer on `AI_QUEUE` that embeds pages into `page_embeddings` (vector search), complementing Postgres full-text search. Pages are (re)indexed on edit; `AI_EMBEDDING_TIMEOUT_MS` bounds a hung embeddings endpoint.
    - `core/ai-chat/external-mcp/` — admins can attach external MCP servers (e.g. Tavily) to give the agent web access. **`ssrf-guard.ts` validates outbound MCP URLs against SSRF** — keep that guard in the path when touching external-MCP connection logic.
 
+### Git-sync (native two-way Docmost ↔ git Markdown sync)
+`integrations/git-sync/` (`GitSyncModule`) + the vendored pure engine in `packages/git-sync`. Off by default; gated by the `GIT_SYNC_ENABLED` master switch (and `GIT_SYNC_SERVICE_USER_ID`, the account git-originated writes are attributed to). Per-space opt-in via `space.settings.gitSync.enabled`, with a second per-space toggle `space.settings.gitSync.autoMergeConflicts` that changes PUSH behavior for a still-conflicted page (one carrying `<<<<<<<`/`>>>>>>>` markers): **off (the safe default)** records a per-page failure and holds the refs so the user resolves the git conflict first (markers never reach Docmost); **on** strips the marker lines and pushes both sides' content. Each enabled space gets an on-disk working "vault" repo; the `GitSyncOrchestrator` runs a debounced + poll-backstop reconcile cycle (PULL Docmost→vault, PUSH vault→Docmost) under a per-space Redis leader lock + in-process mutex (`SpaceLockService`). Writes go through the collaboration layer (so concurrent human edits aren't clobbered) and are stamped `lastUpdatedSource = 'git-sync'` for the listener loop-guard. The in-process `setInterval` orchestration + best-effort lock (no fencing tokens) is a known multi-replica limitation — BullMQ + fencing is the documented future direction.
+
+- **`/git` smart-HTTP host** (`integrations/git-sync/http/`, gated additionally by `GIT_SYNC_HTTP_ENABLED`, which defaults to `GIT_SYNC_ENABLED`): a raw root-mounted Fastify route `/git/<spaceId>.git/...` (registered in `main.ts`, NOT under `/api`) that bridges `git clone`/`fetch`/`push` to `git http-backend`. It authenticates HTTP Basic against `AuthService` (throttled by a `FailedLoginLimiter` mirroring the `/mcp` path), authorizes via `SpaceAbilityFactory` (read = fetch, Manage = push), and gates existence so a non-member gets the SAME 404 as a missing/sync-disabled space (never 403 — that would leak space existence). A push runs the receive-pack under the space lock, then a reconcile cycle.
+- **Schema mirror:** `packages/git-sync/src/lib/docmost-schema.ts` is one of the **three** hand-synced copies of the Tiptap document schema (see Client structure) — keep it in lockstep with `editor-ext` (canonical) and `packages/mcp`.
+
 ### Client structure
 Vite SPA. Code is organized by feature under `apps/client/src/features/*` (mirrors the server domains: `page`, `space`, `comment`, `ai-chat`, `editor`, …). Conventions:
 - **TanStack Query** for server state (one `queries/` file per feature), **Jotai** atoms for local/shared UI state, **Mantine 8** + CSS modules (`*.module.css`) + `postcss-preset-mantine` for UI.
-- The editor is Tiptap; shared node/mark extensions live in `packages/editor-ext` and are imported by **both the client and the server** (collaboration, import/export) — editor schema changes often need to be made in `editor-ext`, not just the client. Note `packages/mcp` does *not* depend on `editor-ext`; it carries its own mirrored copy of the schema, so keep the two in sync manually when the document schema changes.
+- The editor is Tiptap; shared node/mark extensions live in `packages/editor-ext` and are imported by **both the client and the server** (collaboration, import/export) — editor schema changes often need to be made in `editor-ext`, not just the client. Note neither `packages/mcp` nor `packages/git-sync` depends on `editor-ext`; each carries its own mirrored copy of the schema. There are now **three** independent copies (`editor-ext` is canonical, plus `packages/mcp` and `packages/git-sync`), so keep all three in sync manually when the document schema changes.
 - API access goes through `apps/client/src/lib/api-client.ts` (axios). The `@` alias maps to `apps/client/src`.
 - Runtime config is injected at build time by `vite.config.ts` via `define` (`APP_URL`, `COLLAB_URL`, `APP_VERSION`, …) — these come from the root `.env`, not from `import.meta.env`.
 

CHANGELOG.md

@@ -12,6 +12,20 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- **Native two-way Docmost ↔ git Markdown sync.** Opt-in per space (Space
+  settings → a git-sync toggle, plus an `autoMergeConflicts` toggle that controls
+  whether a still-conflicted page is held back or pushed with its conflict
+  markers stripped): each enabled space is mirrored to an on-disk git "vault" of
+  Markdown files and reconciled in both directions (Docmost → vault and vault →
+  Docmost) on a debounced + poll-backstop cycle, under a per-space lock, writing
+  through the collaboration layer so concurrent human edits aren't clobbered.
+  Git-originated changes are attributed to a configurable service account and
+  carry a "git-sync" provenance badge in page history. Optionally exposes a `/git`
+  smart-HTTP host so you can `git clone`/`fetch`/`push` a space directly (HTTP
+  Basic auth, space-permission authorized). Off by default and configured via the
+  `GIT_SYNC_*` environment variables, including `GIT_SYNC_ENABLED`,
+  `GIT_SYNC_SERVICE_USER_ID`, and `GIT_SYNC_HTTP_ENABLED` (see `.env.example`).
+  (#119)
 - **Quick-create regular and temporary notes from the Home and Space screens.**
   The Home screen now shows a second action next to "New note" that creates a
   *temporary* note (one that auto-moves to Trash after the workspace lifetime),
@@ -41,9 +55,50 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   `AI_AGENT_ROLES_CATALOG_URL` env var — an `http(s)://` base URL to the
   catalog's raw files; the image ships a per-branch default baked in CI, and it
   can be overridden at runtime via the env var (see `.env.example`). (#222)
+- **Author footnotes inline from an agent, and deterministic server-side footnote
+  canonicalization on every non-editor write path.** A new MCP `insert_footnote`
+  tool places a footnote at a body anchor by content only — the agent supplies
+  WHERE (anchor text) and WHAT (markdown); the number and the bottom
+  `footnotesList` are derived server-side, so an agent can never assign a number,
+  edit the list, or desync, and a same-content note reuses one definition. Under
+  the hood, the editor's footnote-integrity invariant (one trailing list,
+  numbering by first reference, no orphans/duplicates, no raw `[^id]`) is now
+  enforced as a pure `canonicalizeFootnotes(doc)` on the FULL-document write paths
+  that bypass the editor's plugins: server markdown/HTML import, `PageService`
+  create and full-document (`replace`) updates, the client markdown paste, and the
+  MCP markdown page-import / `update_page` (markdown) / `update_page_json` /
+  `docmost_transform` / `insert_footnote` / `copy_page_content` paths. It is
+  idempotent (a no-op once canonical) and is deliberately NOT applied to
+  append/prepend fragments, nor to COMMENT bodies — a comment may legitimately
+  contain a standalone footnote definition, which canonicalization would drop.
+  (#228)
+
+### Changed
+
+- **Enabling a public share no longer auto-shares the whole sub-tree.** Turning
+  a page "Shared to web" now defaults to the page alone; descendant pages become
+  public only when you explicitly turn on the dedicated "Include sub-pages"
+  toggle. Previously the create call defaulted to including sub-pages, silently
+  exposing every child of a freshly shared page. (#216)
 
 ### Fixed
 
+- **Internal links in exported Markdown no longer lose their visible text.** A
+  link whose target page name had no file extension (e.g. a bare title) was
+  collapsed to empty text during export, producing an unclickable, label-less
+  link; the page name is now preserved. (#204)
+- **Deep pages no longer render a blank breadcrumb while the sidebar tree loads.**
+  The breadcrumb now falls back to the page's own ancestor chain (fetched
+  independently of the lazily-built sidebar tree) so a deep page resolves its
+  trail immediately; navigating away no longer leaves the previously-viewed
+  page's breadcrumb showing until the new one resolves. (#206, #218)
+- **Pasted GitHub-style callouts (`> [!NOTE]` …) now convert to real callouts.**
+  GitHub admonition blocks pasted as Markdown are recognized and rendered as
+  callout blocks instead of plain block-quotes. (#192)
+- **The editor stays read-only until collaboration has synced.** While a page is
+  connecting, the body is shown as a non-editable static view with a
+  "Connecting… (read-only)" banner, so edits typed before the document finishes
+  syncing can no longer be silently dropped. (#218)
 - **A shared page now keeps EXACTLY ONE custom address (`/l/:alias`).** Editing a
   page's vanity slug previously inserted a second `share_aliases` row instead of
   renaming the existing one, leaving the old `/l/<old>` link live forever and
@@ -63,6 +118,20 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   enabled, so the existing reassign-confirm flow (`409 ALIAS_REASSIGN_REQUIRED` →
   "Move custom address?") is discoverable instead of reading as terminal. (#227)
 
+### Security
+
+- **The anonymous public-share page payload is trimmed to an explicit allowlist.**
+  The `/shares/page-info` route (the only unauthenticated path serializing a
+  page + its share) now returns only the fields the public renderer needs;
+  internal metadata — creator/last-updater/contributor ids, space/workspace ids,
+  AI/source bookkeeping, lock/template flags, parent/position and raw timestamps
+  — is no longer exposed to anonymous viewers. (#218)
+- **A forged or mismatched share id can no longer render a page off its slug
+  alone.** When the public URL carries a share id/key, the page must be reachable
+  through that exact share (its own share or an ancestor `includeSubPages`
+  share); any other value now returns the generic "not found" instead of
+  serving the page. (#218)
+
 ## [0.94.0] - 2026-06-26
 
 This release makes AI chat durable and fast: assistant turns are persisted to

Dockerfile

@@ -17,8 +17,9 @@ RUN pnpm build
 
 FROM base AS installer
 
+# git: required by the git-sync VaultGit (shells out to git)
 RUN apt-get update \
-  && apt-get install -y --no-install-recommends curl bash \
+  && apt-get install -y --no-install-recommends curl bash git \
   && rm -rf /var/lib/apt/lists/*
 
 WORKDIR /app
@@ -38,6 +39,14 @@ COPY --from=builder /app/packages/editor-ext/dist /app/packages/editor-ext/dist
 COPY --from=builder /app/packages/editor-ext/package.json /app/packages/editor-ext/package.json
 COPY --from=builder /app/packages/mcp/build /app/packages/mcp/build
 COPY --from=builder /app/packages/mcp/package.json /app/packages/mcp/package.json
+# git-sync: the server loads @docmost/git-sync at runtime via the loader
+# (git-sync.loader.ts), which deliberately does NOT `require()` it — the package is
+# ESM-only, so the loader uses `require.resolve` + a dynamic `import()`. Without
+# these copied build artifacts that resolve/import fails and the server crashes on
+# first use. Built fresh by the builder's `pnpm build` (nx builds the package's tsc
+# `build` target).
+COPY --from=builder /app/packages/git-sync/build /app/packages/git-sync/build
+COPY --from=builder /app/packages/git-sync/package.json /app/packages/git-sync/package.json
 
 # Copy root package files
 COPY --from=builder /app/package.json /app/package.json

README.md

@@ -34,7 +34,7 @@ The goal of the fork is a **100% open, AGPL-only build with no Enterprise-Editio
 | --- | --- |
 | **EE code removed** | Stripped all client and server Enterprise-Edition code; ships as a clean community/AGPL build with no license checks. |
 | **Comment resolution** | Re-implemented from scratch as a community feature (resolve / re-open with Open/Resolved tabs). No EE code reused, available to anyone who can comment. |
-| **Embedded MCP server** | A community MCP server (`@docmost/mcp`, 38 tools) is served over HTTP at `/mcp` — no enterprise license required. Replaces the removed license-gated EE MCP. |
+| **Embedded MCP server** | A community MCP server (`@docmost/mcp`, 39 tools) is served over HTTP at `/mcp` — no enterprise license required. Replaces the removed license-gated EE MCP. |
 | **AI agent chat** | Built-in AI agent chat over your wiki, written from scratch as a community feature — no enterprise license. The agent reads and edits pages on your behalf (scoped to your permissions), with full-text + vector (RAG) search and optional web access via external MCP servers. |
 | **Rebranding** | App logo / name changed from *Docmost* to *Gitmost*. |
 | **Compact page tree** | Default page-tree indentation reduced from 16px to 8px per nesting level. |
@@ -44,7 +44,7 @@ The goal of the fork is a **100% open, AGPL-only build with no Enterprise-Editio
 ### Embedded MCP server
 
 Gitmost has **our own MCP server** — [docmost-mcp](https://github.com/vvzvlad/docmost-mcp),
-which we wrote — **built directly into the app** and served at `/mcp`. It exposes **38
+which we wrote — **built directly into the app** and served at `/mcp`. It exposes **39
 agent-native tools**: surgical per-block edits (patch / insert / delete by id),
 structure-preserving find/replace, scripted `(doc) => doc` transforms with a dry-run diff,
 structured table editing, version history with diff / restore, comments, images and share
@@ -60,7 +60,7 @@ every little fix. And it needs no enterprise license.
 | | **Gitmost `/mcp` (our docmost-mcp)** | Docmost's built-in MCP |
 | --- | :---: | :---: |
 | **Enterprise license** | Not required | Required |
-| **Tools** | 38, agent-native | Coarse (read Markdown, page CRUD, replace whole page) |
+| **Tools** | 39, agent-native | Coarse (read Markdown, page CRUD, replace whole page) |
 | **Per-block edits / find-replace / scripted transforms** | ✅ | — |
 | **Structured table editing, version diff / restore** | ✅ | — |
 | **Comments, images, share links** | ✅ | — |

README.ru.md

@@ -33,7 +33,7 @@
 | --- | --- |
 | **Удалён EE-код** | Вырезан весь код Enterprise-редакции на клиенте и сервере; это чистая community/AGPL-сборка без лицензионных проверок. |
 | **Резолв комментариев** | Переписан с нуля как community-функция (резолв / переоткрытие с вкладками «Открытые» / «Решённые»). EE-код не используется, доступно любому, кто может комментировать. |
-| **Встроенный MCP-сервер** | Community MCP-сервер (`@docmost/mcp`, 38 инструментов) отдаётся по HTTP на `/mcp` — без enterprise-лицензии. Заменяет удалённый лицензируемый EE MCP. |
+| **Встроенный MCP-сервер** | Community MCP-сервер (`@docmost/mcp`, 39 инструментов) отдаётся по HTTP на `/mcp` — без enterprise-лицензии. Заменяет удалённый лицензируемый EE MCP. |
 | **Чат с AI-агентом** | Встроенный чат с AI-агентом по содержимому вики, написанный с нуля как community-функция — без enterprise-лицензии. Агент читает и редактирует страницы от вашего имени (в рамках ваших прав), с полнотекстовым + векторным (RAG) поиском и опциональным доступом в интернет через внешние MCP-серверы. |
 | **Ребрендинг** | Логотип / название приложения изменены с *Docmost* на *Gitmost*. |
 | **Компактное дерево страниц** | Отступ дерева страниц по умолчанию уменьшен с 16px до 8px на уровень вложенности. |
@@ -44,7 +44,7 @@
 
 В Gitmost есть **наш собственный MCP-сервер** — [docmost-mcp](https://github.com/vvzvlad/docmost-mcp),
 который мы написали сами, — **встроенный прямо в приложение** и доступный на `/mcp`. Он даёт
-**38 agent-native инструментов**: точечное редактирование по блокам (patch / insert / delete
+**39 agent-native инструментов**: точечное редактирование по блокам (patch / insert / delete
 по id), find/replace с сохранением структуры, скриптовые трансформации `(doc) => doc` с
 предпросмотром диффа, структурное редактирование таблиц, история версий с диффом /
 восстановлением, комментарии, изображения и ссылки на шаринг — всё применяется через слой
@@ -60,7 +60,7 @@ real-time-коллаборации Docmost, поэтому запись нико
 | | **`/mcp` в Gitmost (наш docmost-mcp)** | Родной MCP у Docmost |
 | --- | :---: | :---: |
 | **Enterprise-лицензия** | Не нужна | Нужна |
-| **Инструменты** | 38, agent-native | Примитивные (Markdown, CRUD страниц, замена целиком) |
+| **Инструменты** | 39, agent-native | Примитивные (Markdown, CRUD страниц, замена целиком) |
 | **Правки по блокам / find-replace / скриптовые трансформации** | ✅ | — |
 | **Структурное редактирование таблиц, дифф / восстановление версий** | ✅ | — |
 | **Комментарии, изображения, ссылки на шаринг** | ✅ | — |

agent-roles-catalog/bundles/editorial/en.json

@@ -24,8 +24,8 @@
       "slug": "fact-checker",
       "emoji": "🔍",
       "name": "Fact-checker",
-      "description": "Verifies facts, figures, dates, names, and quotes with web search. Confirms, corrects, or flags the unverifiable — with a verdict and a source.",
-      "instructions": "You are a fact-checker at Gitmost, verifying the factual accuracy of non-fiction texts (articles, opinion pieces, technical material, blogs, documentation). You have access to web search — use it to verify. Communicate with the user in English.\n\nWHAT YOU DO\nVerify every checkable claim: names, titles, positions; dates, chronology, sequence; numbers, statistics, proportions, units; quotations and their attribution; technical facts, terms, versions, specifications; causal and logical claims, and internal consistency.\n\nRemember the weakness of machine text: an LLM does not fact-check and will confidently state falsehoods, invent non-existent terms, conflate near-neighbor entities (e.g. claim \"handwriting understanding\" where it was template-based recognition), and insert pseudo-precise numbers. Be especially wary of smoothly written but unverifiable claims.\n\nA VERDICT FOR EACH CLAIM\n- [Verified] — the fact is correct; cite the source.\n- [Incorrect] — the fact is wrong; give the correction and the source.\n- [Unverified] — probably correct but not confirmed; say what's needed to verify.\n- [Unverifiable] — the claim can't be checked in principle (no source, too vague).\n- [Opinion] — not a factual claim, not subject to checking.\n\nSource rule: rely on primary sources (original data, documentation, official site), not retellings. One primary source or two independent secondary sources is a reasonable minimum. Cite the source in the comment.\n\nWHAT YOU DON'T DO\n- Don't fix style, grammar, punctuation, structure, or typography — those are other roles.\n- Don't rewrite the text. You confirm, correct, or flag — the decision is the author's.\n- Don't judge opinions or subjective phrasing as facts.\n- Don't fabricate confirmations. If you can't verify, honestly mark [Unverified] or [Unverifiable]. Never confirm a fact you don't know.\n\nHOW TO LEAVE COMMENTS\nYou don't edit the text directly. For each checked claim, select the span via the MCP tool and leave a comment. Open the comment with the label `[Facts]`, then the verdict, the correction (if any), and the source. Tag severity:\n- [Critical] — a factual error, especially in numbers, names, or quotes, or a claim that risks misinformation.\n- [Major] — a doubtful or unconfirmed claim that needs a source.\n- [Minor] — a small correction, or false precision worth rounding or confirming.\n\nTONE\nNeutral and precise. Don't argue with the author's stance — check facts, not views.\n\nWHEN UNSURE\nBetter to honestly flag \"can't confirm\" than to give a false confirmation.",
+      "description": "Verifies facts, figures, dates, names, and quotes with web search. Finds errors and flags the doubtful or unverifiable — with a verdict and a source.",
+      "instructions": "You are a fact-checker at Gitmost, verifying the factual accuracy of non-fiction texts (articles, opinion pieces, technical material, blogs, documentation). You have access to web search — use it to verify. Communicate with the user in English.\n\nWHAT YOU DO\nVerify every checkable claim: names, titles, positions; dates, chronology, sequence; numbers, statistics, proportions, units; quotations and their attribution; technical facts, terms, versions, specifications; causal and logical claims, and internal consistency. Your job is to find errors and doubtful spots, not to confirm what is already correct.\n\nRemember the weakness of machine text: an LLM does not fact-check and will confidently state falsehoods, invent non-existent terms, conflate near-neighbor entities (e.g. claim \"handwriting understanding\" where it was template-based recognition), and insert pseudo-precise numbers. Be especially wary of smoothly written but unverifiable claims.\n\nVERDICTS (for problem claims only)\nDon't comment on correct facts — don't write or mark that a fact is right or confirmed. Leave a verdict only where there is a problem:\n- [Incorrect] — the fact is wrong; give the correction and the source.\n- [Unverified] — probably correct but not confirmed; say what's needed to verify.\n- [Unverifiable] — the claim can't be checked in principle (no source, too vague).\n- [Opinion] — not a factual claim, not subject to checking.\n\nSource rule: rely on primary sources (original data, documentation, official site), not retellings. One primary source or two independent secondary sources is a reasonable minimum. Cite the source in the comment.\n\nWHAT YOU DON'T DO\n- Don't fix style, grammar, punctuation, structure, or typography — those are other roles.\n- Don't rewrite the text. You refute or flag a problem — the decision is the author's.\n- Don't judge opinions or subjective phrasing as facts.\n- Don't write or comment that a fact is right or confirmed: your job is to find errors, not to confirm facts.\n- Don't fabricate confirmations. If you can't verify, honestly mark [Unverified] or [Unverifiable].\n\nHOW TO LEAVE COMMENTS\nYou don't edit the text directly. For each problem claim (an error, a doubt, an unverifiable statement), select the span via the MCP tool and leave a comment; leave no comment on correct facts. Open the comment with the label `[Facts]`, then the verdict, the correction (if any), and the source. Tag severity:\n- [Critical] — a factual error, especially in numbers, names, or quotes, or a claim that risks misinformation.\n- [Major] — a doubtful or unconfirmed claim that needs a source.\n- [Minor] — a small correction, or false precision worth rounding or confirming.\n\nTONE\nNeutral and precise. Don't argue with the author's stance — check facts, not views.\n\nWHEN UNSURE\nBetter to honestly flag \"can't confirm\" than to give a false confirmation.",
       "autoStart": true,
       "launchMessage": "Take the current page into work. If there is none, ask the user which page to work on."
     },

agent-roles-catalog/index.json

@@ -12,7 +12,7 @@
       "roles": [
         { "slug": "structural-editor", "version": 2 },
         { "slug": "line-editor", "version": 2 },
-        { "slug": "fact-checker", "version": 2 },
+        { "slug": "fact-checker", "version": 3 },
         { "slug": "proofreader", "version": 3 },
         { "slug": "narrator", "version": 1 }
       ]

agent-roles-catalog/scripts/content-hashes.json

@@ -1,7 +1,7 @@
 {
   "fact-checker": {
-    "version": 2,
-    "hash": "d7ad1dae07d6f4321e7d40c5b36259dbf930264d748834809c4fb77294bf72e3"
+    "version": 3,
+    "hash": "a94931fbd20272570a588c72159ac9e48a89c99bd8f718449cda5e7ca4280fdf"
   },
   "line-editor": {
     "version": 2,

apps/client/public/locales/en-US/translation.json

@@ -1217,6 +1217,8 @@
   "Ran tool {{name}}": "Ran tool {{name}}",
   "AI-agent": "AI-agent",
   "Edited by AI agent on behalf of {{name}}": "Edited by AI agent on behalf of {{name}}",
+  "Git sync": "Git sync",
+  "Synced from Git on behalf of {{name}}": "Synced from Git on behalf of {{name}}",
   "Endpoints": "Endpoints",
   "where we fetch models": "where we fetch models",
   "All endpoints are OpenAI-compatible. Point the Base URL at OpenAI, OpenRouter, a local Ollama, or any self-hosted server.": "All endpoints are OpenAI-compatible. Point the Base URL at OpenAI, OpenRouter, a local Ollama, or any self-hosted server.",
@@ -1241,6 +1243,10 @@
   "MCP server": "MCP server",
   "expose the workspace": "expose the workspace",
   "Enable MCP server": "Enable MCP server",
+  "Enable Git sync": "Enable Git sync",
+  "Sync this space's pages to a Git repository.": "Sync this space's pages to a Git repository.",
+  "Auto-merge conflicts on push": "Auto-merge conflicts on push",
+  "When off (recommended), a page whose content still has unresolved Git conflict markers is skipped on push until you resolve the conflict in Git. When on, the markers are stripped and both sides' content is pushed.": "When off (recommended), a page whose content still has unresolved Git conflict markers is skipped on push until you resolve the conflict in Git. When on, the markers are stripped and both sides' content is pushed.",
   "Exposes the workspace as an MCP server at /mcp — this provides a capability, it doesn't consume a model.": "Exposes the workspace as an MCP server at /mcp — this provides a capability, it doesn't consume a model.",
   "Resolves to {{url}}": "Resolves to {{url}}",
   "Model": "Model",
@@ -1364,5 +1370,6 @@
   "Already up to date": "Already up to date",
   "Updated to the latest version": "Updated to the latest version",
   "This role is no longer in the catalog": "This role is no longer in the catalog",
-  "This language is no longer available in the catalog": "This language is no longer available in the catalog"
+  "This language is no longer available in the catalog": "This language is no longer available in the catalog",
+  "Connecting… (read-only)": "Connecting… (read-only)"
 }

apps/client/public/locales/ru-RU/translation.json

@@ -1222,5 +1222,6 @@
   "Already up to date": "Уже актуальна",
   "Updated to the latest version": "Обновлено до последней версии",
   "This role is no longer in the catalog": "Эта роль больше не представлена в каталоге",
-  "This language is no longer available in the catalog": "Этот язык больше не доступен в каталоге"
+  "This language is no longer available in the catalog": "Этот язык больше не доступен в каталоге",
+  "Connecting… (read-only)": "Подключение… (только чтение)"
 }

apps/client/src/components/ui/git-sync-badge.tsx

@@ -0,0 +1,37 @@
+import { Badge, Tooltip } from "@mantine/core";
+import { IconGitMerge } from "@tabler/icons-react";
+import { useTranslation } from "react-i18next";
+
+interface GitSyncBadgeProps {
+  authorName?: string;
+}
+
+/**
+ * Badge marking a version produced by git-sync (provenance §8.1). The history
+ * version is created on the PUSH path — when an incoming git body is written back
+ * into the Docmost doc — not by the pull itself. Like {@link AiAgentBadge} it is
+ * ADDITIVE — shown next to the human author, never replacing them — but a git-sync
+ * edit is NOT an agent edit and has no chat to deep-link into, so it is a small,
+ * neutral, non-clickable label.
+ */
+export function GitSyncBadge({ authorName }: GitSyncBadgeProps) {
+  const { t } = useTranslation();
+
+  const tooltip = t("Synced from Git on behalf of {{name}}", {
+    name: authorName ?? "",
+  });
+
+  return (
+    <Tooltip label={tooltip} withArrow>
+      <Badge
+        size="sm"
+        variant="light"
+        color="gray"
+        radius="sm"
+        leftSection={<IconGitMerge size={12} stroke={2} />}
+      >
+        {t("Git sync")}
+      </Badge>
+    </Tooltip>
+  );
+}

apps/client/src/features/editor/components/emoji-menu/utils.test.ts

@@ -0,0 +1,100 @@
+import { describe, it, expect, beforeEach } from "vitest";
+import {
+  sortFrequentlyUsedEmoji,
+  getFrequentlyUsedEmoji,
+  LOCAL_STORAGE_FREQUENT_KEY,
+} from "./utils";
+
+describe("sortFrequentlyUsedEmoji", () => {
+  it("orders known emoji by descending usage count", async () => {
+    const result = await sortFrequentlyUsedEmoji({
+      rocket: 1,
+      joy: 9,
+      heart_eyes: 5,
+    });
+    expect(result.map((e) => e.id)).toEqual(["joy", "heart_eyes", "rocket"]);
+  });
+
+  it("caps the result at the top 5 most frequent", async () => {
+    const result = await sortFrequentlyUsedEmoji({
+      rocket: 1,
+      joy: 2,
+      heart_eyes: 3,
+      grinning: 4,
+      laughing: 5,
+      scream: 6,
+      sweat_smile: 7,
+    });
+    expect(result).toHaveLength(5);
+    // Highest counts retained, lowest (rocket:1, joy:2) dropped.
+    expect(result.map((e) => e.id)).toEqual([
+      "sweat_smile",
+      "scream",
+      "laughing",
+      "grinning",
+      "heart_eyes",
+    ]);
+  });
+
+  it("drops ids that have no matching emoji in the index", async () => {
+    const result = await sortFrequentlyUsedEmoji({
+      __definitely_not_a_real_emoji_id__: 100,
+      rocket: 1,
+    });
+    expect(result.map((e) => e.id)).toEqual(["rocket"]);
+  });
+
+  it("maps each entry to its native glyph and a command", async () => {
+    const [entry] = await sortFrequentlyUsedEmoji({ rocket: 5 });
+    expect(entry.id).toBe("rocket");
+    expect(typeof entry.emoji).toBe("string");
+    expect(entry.emoji.length).toBeGreaterThan(0);
+    expect(typeof entry.command).toBe("function");
+  });
+
+  it("returns an empty list for empty input", async () => {
+    expect(await sortFrequentlyUsedEmoji({})).toEqual([]);
+  });
+});
+
+describe("getFrequentlyUsedEmoji", () => {
+  beforeEach(() => {
+    localStorage.clear();
+  });
+
+  it("falls back to the default map when nothing is stored", () => {
+    const result = getFrequentlyUsedEmoji();
+    expect(result["+1"]).toBe(10);
+    expect(result["rocket"]).toBe(1);
+  });
+
+  it("parses a valid stored JSON map", () => {
+    localStorage.setItem(
+      LOCAL_STORAGE_FREQUENT_KEY,
+      JSON.stringify({ rocket: 42 }),
+    );
+    expect(getFrequentlyUsedEmoji()).toEqual({ rocket: 42 });
+  });
+
+  // BUG (issue #204, Phase 2): getFrequentlyUsedEmoji() does an unprotected
+  // JSON.parse() of the raw localStorage value. A corrupt value (e.g. truncated
+  // by a crash, or written by another tab/extension) makes the emoji menu throw
+  // on open instead of degrading gracefully to the default set.
+  //
+  // Documented with it.fails: this asserts the DESIRED behavior (return a sane
+  // default, never throw). It currently FAILS because the function throws —
+  // flip to `it()` once utils.ts guards the JSON.parse.
+  it.fails(
+    "should degrade to a sane default on corrupt localStorage (currently throws)",
+    () => {
+      localStorage.setItem(LOCAL_STORAGE_FREQUENT_KEY, "{not valid json");
+      let result: Record<string, number> | undefined;
+      expect(() => {
+        result = getFrequentlyUsedEmoji();
+      }).not.toThrow();
+      // Should hand back a usable, non-empty map rather than nothing.
+      expect(result).toBeTruthy();
+      expect(Object.keys(result ?? {}).length).toBeGreaterThan(0);
+    },
+  );
+});

apps/client/src/features/editor/components/table/handle/lib/sort-cells.test.ts

@@ -0,0 +1,163 @@
+import { describe, it, expect } from "vitest";
+import type { Node as ProseMirrorNode } from "@tiptap/pm/model";
+import {
+  isHeaderCell,
+  sortItems,
+  weaveItems,
+  type SortableItem,
+} from "./sort-cells";
+
+// isHeaderCell only reads node.type.name and node.attrs?.header, so a minimal
+// duck-typed node is sufficient (no real ProseMirror schema needed).
+function fakeNode(typeName: string, attrs: Record<string, unknown> = {}) {
+  return { type: { name: typeName }, attrs } as unknown as ProseMirrorNode;
+}
+
+function item<T>(
+  payload: T,
+  text: string,
+  originalOrder: number,
+  opts: { isHeader?: boolean; isEmpty?: boolean } = {},
+): SortableItem<T> {
+  return {
+    payload,
+    text,
+    originalOrder,
+    isHeader: opts.isHeader ?? false,
+    isEmpty: opts.isEmpty ?? text.trim() === "",
+  };
+}
+
+describe("isHeaderCell", () => {
+  it("recognizes the tableHeader node type", () => {
+    expect(isHeaderCell(fakeNode("tableHeader"))).toBe(true);
+  });
+
+  it("recognizes the snake_case table_header node type", () => {
+    expect(isHeaderCell(fakeNode("table_header"))).toBe(true);
+  });
+
+  it("treats a plain cell with header:true attr as a header", () => {
+    expect(isHeaderCell(fakeNode("tableCell", { header: true }))).toBe(true);
+  });
+
+  it("returns false for a regular body cell", () => {
+    expect(isHeaderCell(fakeNode("tableCell", { header: false }))).toBe(false);
+    expect(isHeaderCell(fakeNode("tableCell"))).toBe(false);
+  });
+});
+
+describe("sortItems", () => {
+  it("sorts non-empty rows ascending using a base/numeric collator", () => {
+    const data = [
+      item("c", "cherry", 0),
+      item("a", "Apple", 1),
+      item("b", "banana", 2),
+    ];
+    expect(sortItems(data, "asc").map((i) => i.payload)).toEqual([
+      "a",
+      "b",
+      "c",
+    ]);
+  });
+
+  it("sorts descending when direction is desc", () => {
+    const data = [
+      item("a", "apple", 0),
+      item("b", "banana", 1),
+      item("c", "cherry", 2),
+    ];
+    expect(sortItems(data, "desc").map((i) => i.payload)).toEqual([
+      "c",
+      "b",
+      "a",
+    ]);
+  });
+
+  it("orders numerically, not lexically (numeric collator)", () => {
+    const data = [
+      item("ten", "10", 0),
+      item("two", "2", 1),
+      item("one", "1", 2),
+    ];
+    expect(sortItems(data, "asc").map((i) => i.payload)).toEqual([
+      "one",
+      "two",
+      "ten",
+    ]);
+  });
+
+  it("always pushes empty cells to the bottom regardless of direction", () => {
+    const data = [
+      item("empty", "", 0, { isEmpty: true }),
+      item("b", "banana", 1),
+      item("a", "apple", 2),
+    ];
+    const asc = sortItems(data, "asc");
+    expect(asc.map((i) => i.payload)).toEqual(["a", "b", "empty"]);
+    const desc = sortItems(data, "desc");
+    // Empty stays last even when the rest is reversed.
+    expect(desc[desc.length - 1].payload).toBe("empty");
+  });
+
+  it("keeps empty cells in their original relative order (stable)", () => {
+    const data = [
+      item("e1", "", 5, { isEmpty: true }),
+      item("e2", "", 2, { isEmpty: true }),
+      item("a", "apple", 9),
+    ];
+    const sorted = sortItems(data, "asc");
+    // e2 (originalOrder 2) before e1 (originalOrder 5).
+    expect(sorted.map((i) => i.payload)).toEqual(["a", "e2", "e1"]);
+  });
+
+  it("does not mutate the input array", () => {
+    const data = [item("b", "banana", 0), item("a", "apple", 1)];
+    const snapshot = data.map((i) => i.payload);
+    sortItems(data, "asc");
+    expect(data.map((i) => i.payload)).toEqual(snapshot);
+  });
+});
+
+describe("weaveItems", () => {
+  it("keeps header rows pinned in place and fills body slots from sorted data", () => {
+    const header = item("H", "Name", 0, { isHeader: true });
+    const all = [
+      header,
+      item("orig-b", "b", 1),
+      item("orig-a", "a", 2),
+    ];
+    const sortedBody = [item("orig-a", "a", 2), item("orig-b", "b", 1)];
+
+    const woven = weaveItems(all, sortedBody);
+    // Header never moves out of row 0...
+    expect(woven[0]).toBe(header);
+    // ...and the body positions are filled in sorted order.
+    expect(woven.slice(1).map((i) => i.payload)).toEqual(["orig-a", "orig-b"]);
+  });
+
+  it("does not consume body data for header positions (header stays at top)", () => {
+    const header = item("H", "head", 0, { isHeader: true });
+    const all = [header, item("x", "x", 1), item("y", "y", 2)];
+    const sortedBody = [item("y", "y", 2), item("x", "x", 1)];
+    const woven = weaveItems(all, sortedBody);
+    expect(woven[0].isHeader).toBe(true);
+    expect(woven.filter((i) => !i.isHeader).map((i) => i.payload)).toEqual([
+      "y",
+      "x",
+    ]);
+  });
+
+  it("interleaves correctly when a header sits between body rows", () => {
+    const header = item("H", "head", 1, { isHeader: true });
+    const all = [
+      item("b1", "b1", 0),
+      header,
+      item("b2", "b2", 2),
+    ];
+    const sortedBody = [item("b2", "b2", 2), item("b1", "b1", 0)];
+    const woven = weaveItems(all, sortedBody);
+    expect(woven.map((i) => i.payload)).toEqual(["b2", "H", "b1"]);
+    expect(woven[1]).toBe(header);
+  });
+});

apps/client/src/features/editor/editor-sync-state.test.ts

@@ -0,0 +1,32 @@
+import { describe, it, expect } from "vitest";
+import { WebSocketStatus } from "@hocuspocus/provider";
+import { isCollabSynced, isBodyEditable } from "./editor-sync-state";
+
+describe("isCollabSynced", () => {
+  it("is true only when Connected and synced", () => {
+    expect(isCollabSynced(WebSocketStatus.Connected, true)).toBe(true);
+  });
+
+  it("is false while connecting or not yet synced", () => {
+    expect(isCollabSynced(WebSocketStatus.Connecting, true)).toBe(false);
+    expect(isCollabSynced(WebSocketStatus.Connected, false)).toBe(false);
+    expect(isCollabSynced(WebSocketStatus.Disconnected, true)).toBe(false);
+  });
+});
+
+describe("isBodyEditable (pre-sync data-loss gate, #218)", () => {
+  const base = { editable: true, inEditMode: true, showStatic: false };
+
+  it("allows editing only after the static (pre-sync) phase ends", () => {
+    expect(isBodyEditable(base)).toBe(true);
+  });
+
+  it("never editable while the static read-only editor is shown", () => {
+    expect(isBodyEditable({ ...base, showStatic: true })).toBe(false);
+  });
+
+  it("honors read-only and view mode", () => {
+    expect(isBodyEditable({ ...base, editable: false })).toBe(false);
+    expect(isBodyEditable({ ...base, inEditMode: false })).toBe(false);
+  });
+});

apps/client/src/features/editor/editor-sync-state.ts

@@ -0,0 +1,32 @@
+import { WebSocketStatus } from "@hocuspocus/provider";
+
+/**
+ * The collab document is usable only once the provider is Connected AND has
+ * synced (both the local IndexedDB replica and the remote room). Until then the
+ * in-browser Y.Doc is empty/stale, so edits would either be dropped or clobber
+ * the server's authoritative doc when it finally arrives.
+ */
+export function isCollabSynced(
+  status: WebSocketStatus | string,
+  isSynced: boolean,
+): boolean {
+  return status === WebSocketStatus.Connected && isSynced;
+}
+
+/**
+ * Whether the page BODY editor may accept edits.
+ *
+ * `showStatic` is true during the pre-sync window (a read-only static editor is
+ * shown). Gating editability on `!showStatic` guarantees the body never becomes
+ * editable before the collab doc is synced, so early keystrokes on a freshly
+ * created page can't land only in local ProseMirror and then be lost when the
+ * server's initial empty doc syncs in (#218). Read-only and view modes are
+ * still honored via `editable`/`inEditMode`.
+ */
+export function isBodyEditable(opts: {
+  editable: boolean;
+  inEditMode: boolean;
+  showStatic: boolean;
+}): boolean {
+  return opts.editable && opts.inEditMode && !opts.showStatic;
+}

apps/client/src/features/editor/extensions/markdown-clipboard.canonicalize.test.ts

@@ -0,0 +1,168 @@
+import { describe, it, expect } from "vitest";
+import { Editor } from "@tiptap/core";
+import { Document } from "@tiptap/extension-document";
+import { Paragraph } from "@tiptap/extension-paragraph";
+import { Text } from "@tiptap/extension-text";
+import { Node as PMNode, Fragment, Slice } from "@tiptap/pm/model";
+import {
+  FootnoteReference,
+  FootnotesList,
+  FootnoteDefinition,
+  FOOTNOTE_REFERENCE_NAME,
+  FOOTNOTE_DEFINITION_NAME,
+  FOOTNOTES_LIST_NAME,
+} from "@docmost/editor-ext";
+import { canonicalizePastedFootnotes } from "./markdown-clipboard";
+
+/**
+ * A markdown paste builds its ProseMirror fragment via DOM -> parseSlice and is
+ * applied with a manual transaction (handlePaste returns true), so it bypasses
+ * the editor's footnoteSyncPlugin — which never reorders an existing list. These
+ * tests pin canonicalizePastedFootnotes, the focused hook that makes a pasted
+ * out-of-order markdown footnote block come out canonical (issue #228).
+ */
+
+const extensions = [
+  Document,
+  Paragraph,
+  Text,
+  FootnoteReference,
+  FootnotesList,
+  FootnoteDefinition,
+];
+
+function makeSchema() {
+  const editor = new Editor({ extensions, content: { type: "doc", content: [] } });
+  const { schema } = editor;
+  return { editor, schema };
+}
+
+/** List footnote def ids of the (single) footnotesList in a slice, in order. */
+function listIds(slice: Slice): string[] {
+  const out: string[] = [];
+  slice.content.forEach((node: PMNode) => {
+    if (node.type.name === FOOTNOTES_LIST_NAME) {
+      node.content.forEach((def: PMNode) => {
+        if (def.type.name === FOOTNOTE_DEFINITION_NAME) out.push(def.attrs.id);
+      });
+    }
+  });
+  return out;
+}
+
+function hasList(slice: Slice): boolean {
+  let found = false;
+  slice.content.forEach((n: PMNode) => {
+    if (n.type.name === FOOTNOTES_LIST_NAME) found = true;
+  });
+  return found;
+}
+
+describe("canonicalizePastedFootnotes", () => {
+  it("reorders a pasted block to reference order, dedups reuse, drops orphans", () => {
+    const { editor, schema } = makeSchema();
+    // Body references c, a, b (and again a => reuse); definitions a, b, c, z
+    // (z is an orphan) — the exact shape a markdown paste produces.
+    const slice = new Slice(
+      Fragment.fromArray([
+        schema.nodes.paragraph.create(null, [
+          schema.text("body "),
+          schema.nodes[FOOTNOTE_REFERENCE_NAME].create({ id: "c" }),
+          schema.nodes[FOOTNOTE_REFERENCE_NAME].create({ id: "a" }),
+          schema.nodes[FOOTNOTE_REFERENCE_NAME].create({ id: "b" }),
+          schema.nodes[FOOTNOTE_REFERENCE_NAME].create({ id: "a" }),
+        ]),
+        schema.nodes[FOOTNOTES_LIST_NAME].create(null, [
+          schema.nodes[FOOTNOTE_DEFINITION_NAME].create({ id: "a" }, [
+            schema.nodes.paragraph.create(null, [schema.text("note A")]),
+          ]),
+          schema.nodes[FOOTNOTE_DEFINITION_NAME].create({ id: "b" }, [
+            schema.nodes.paragraph.create(null, [schema.text("note B")]),
+          ]),
+          schema.nodes[FOOTNOTE_DEFINITION_NAME].create({ id: "c" }, [
+            schema.nodes.paragraph.create(null, [schema.text("note C")]),
+          ]),
+          schema.nodes[FOOTNOTE_DEFINITION_NAME].create({ id: "z" }, [
+            schema.nodes.paragraph.create(null, [schema.text("orphan")]),
+          ]),
+        ]),
+      ]),
+      0,
+      0,
+    );
+
+    const out = canonicalizePastedFootnotes(slice, schema);
+    // Reference order, orphan z dropped, reused a appears once.
+    expect(listIds(out)).toEqual(["c", "a", "b"]);
+    editor.destroy();
+  });
+
+  it("leaves a reference-ONLY paste untouched (no synthesized definitions)", () => {
+    // A paste that reuses an id defined in the TARGET doc must NOT gain a
+    // synthesized empty definition here — it carries no footnotesList of its own.
+    const { editor, schema } = makeSchema();
+    const slice = new Slice(
+      Fragment.from(
+        schema.nodes.paragraph.create(null, [
+          schema.text("see "),
+          schema.nodes[FOOTNOTE_REFERENCE_NAME].create({ id: "a" }),
+        ]),
+      ),
+      0,
+      0,
+    );
+    const out = canonicalizePastedFootnotes(slice, schema);
+    expect(hasList(out)).toBe(false);
+    expect(out).toBe(slice); // returned unchanged (same reference)
+    editor.destroy();
+  });
+
+  it("leaves a definitions-ONLY paste untouched (no references -> no empty paste)", () => {
+    // A whole-block paste of ONLY definitions (a footnotesList with no matching
+    // footnoteReference anywhere in the selection). Canonicalizing it would strip
+    // the reference-less list -> an EMPTY paste, losing the pasted text. The hook
+    // must leave such a block untouched.
+    const { editor, schema } = makeSchema();
+    const slice = new Slice(
+      Fragment.fromArray([
+        schema.nodes[FOOTNOTES_LIST_NAME].create(null, [
+          schema.nodes[FOOTNOTE_DEFINITION_NAME].create({ id: "a" }, [
+            schema.nodes.paragraph.create(null, [schema.text("note A")]),
+          ]),
+          schema.nodes[FOOTNOTE_DEFINITION_NAME].create({ id: "b" }, [
+            schema.nodes.paragraph.create(null, [schema.text("note B")]),
+          ]),
+        ]),
+      ]),
+      0,
+      0,
+    );
+    const out = canonicalizePastedFootnotes(slice, schema);
+    expect(out).toBe(slice); // returned unchanged (same reference, content kept)
+    expect(listIds(out)).toEqual(["a", "b"]);
+    editor.destroy();
+  });
+
+  it("leaves an open (partial) slice untouched even if it carries a list", () => {
+    // An open slice (openStart/openEnd > 0) is a partial selection, not a
+    // standalone block, so it is returned as-is BEFORE any footnote handling.
+    const { editor, schema } = makeSchema();
+    const slice = new Slice(
+      Fragment.fromArray([
+        schema.nodes.paragraph.create(null, [
+          schema.nodes[FOOTNOTE_REFERENCE_NAME].create({ id: "a" }),
+        ]),
+        schema.nodes[FOOTNOTES_LIST_NAME].create(null, [
+          schema.nodes[FOOTNOTE_DEFINITION_NAME].create({ id: "a" }, [
+            schema.nodes.paragraph.create(null, [schema.text("A")]),
+          ]),
+        ]),
+      ]),
+      1,
+      1,
+    );
+    const out = canonicalizePastedFootnotes(slice, schema);
+    expect(out).toBe(slice);
+    editor.destroy();
+  });
+});

apps/client/src/features/editor/extensions/markdown-clipboard.test.ts

@@ -0,0 +1,126 @@
+import { describe, it, expect } from "vitest";
+import { normalizeTableColumnWidths } from "./markdown-clipboard";
+
+// normalizeTableColumnWidths mutates a DOM subtree (jsdom provides document).
+function root(html: string): HTMLElement {
+  const div = document.createElement("div");
+  div.innerHTML = html;
+  return div;
+}
+
+function firstRowColWidths(container: HTMLElement): (string | null)[] {
+  const row = container.querySelector("tr");
+  return Array.from(row?.children ?? []).map((c) =>
+    c.getAttribute("colwidth"),
+  );
+}
+
+describe("normalizeTableColumnWidths", () => {
+  // The core "squash столбцов вставленной таблицы" concern: markdown has no
+  // widths, so every pasted table would otherwise render at table-layout:fixed
+  // / 100% and squash columns. This stamps an explicit per-column px width.
+  it("stamps the default px width on every column when no widths are present", () => {
+    const container = root(
+      "<table><tbody><tr><td>a</td><td>b</td><td>c</td></tr></tbody></table>",
+    );
+    normalizeTableColumnWidths(container);
+    expect(firstRowColWidths(container)).toEqual(["150", "150", "150"]);
+  });
+
+  it("derives column widths from a colgroup", () => {
+    const container = root(
+      "<table>" +
+        '<colgroup><col style="width:200px"><col style="width:80px"></colgroup>' +
+        "<tbody><tr><td>a</td><td>b</td></tr></tbody>" +
+        "</table>",
+    );
+    normalizeTableColumnWidths(container);
+    expect(firstRowColWidths(container)).toEqual(["200", "80"]);
+  });
+
+  it("derives column widths from per-cell width attributes", () => {
+    const container = root(
+      '<table><tbody><tr><td width="120">a</td><td width="90">b</td></tr></tbody></table>',
+    );
+    normalizeTableColumnWidths(container);
+    expect(firstRowColWidths(container)).toEqual(["120", "90"]);
+  });
+
+  it("derives column widths from a cell style:width:px", () => {
+    const container = root(
+      '<table><tbody><tr><td style="width:140px">a</td><td>b</td></tr></tbody></table>',
+    );
+    normalizeTableColumnWidths(container);
+    // First cell width parsed; a fully-unmeasured column is left untouched
+    // (the 100 fallback only fills in NULL gaps inside an otherwise-measured
+    // multi-column slice, e.g. a colspan).
+    expect(firstRowColWidths(container)).toEqual(["140", null]);
+  });
+
+  it("fills a null gap inside a measured colspanned slice with 100", () => {
+    // colgroup gives [200, null]; the single colspan=2 cell spans both, so its
+    // slice is [200, null] -> the null is backfilled to 100 => "200,100".
+    const container = root(
+      "<table>" +
+        '<colgroup><col style="width:200px"><col></colgroup>' +
+        '<tbody><tr><td colspan="2">merged</td></tr></tbody>' +
+        "</table>",
+    );
+    normalizeTableColumnWidths(container);
+    expect(firstRowColWidths(container)).toEqual(["200,100"]);
+  });
+
+  it("splits a measured width across a colspanned cell", () => {
+    const container = root(
+      '<table><tbody><tr><td colspan="2" width="300">merged</td><td width="100">x</td></tr></tbody></table>',
+    );
+    normalizeTableColumnWidths(container);
+    // 300 / colspan(2) = 150 per underlying column => "150,150" on the merged cell.
+    expect(firstRowColWidths(container)).toEqual(["150,150", "100"]);
+  });
+
+  it("falls back to the default width per spanned column when nothing is measurable", () => {
+    const container = root(
+      '<table><tbody><tr><td colspan="2">merged</td><td>x</td></tr></tbody></table>',
+    );
+    normalizeTableColumnWidths(container);
+    expect(firstRowColWidths(container)).toEqual(["150,150", "150"]);
+  });
+
+  it("leaves cells that already have a colwidth untouched", () => {
+    const container = root(
+      '<table><tbody><tr><td colwidth="42">a</td><td>b</td></tr></tbody></table>',
+    );
+    normalizeTableColumnWidths(container);
+    expect(firstRowColWidths(container)).toEqual(["42", "150"]);
+  });
+
+  it("normalizes every table in the subtree", () => {
+    const container = root(
+      "<table><tbody><tr><td>a</td></tr></tbody></table>" +
+        "<table><tbody><tr><td>b</td><td>c</td></tr></tbody></table>",
+    );
+    normalizeTableColumnWidths(container);
+    const tables = container.querySelectorAll("table");
+    const widths = Array.from(tables).map((t) =>
+      Array.from(t.querySelector("tr")!.children).map((c) =>
+        c.getAttribute("colwidth"),
+      ),
+    );
+    expect(widths).toEqual([["150"], ["150", "150"]]);
+  });
+
+  it("only annotates the first row (column widths are defined once)", () => {
+    const container = root(
+      "<table><tbody>" +
+        "<tr><td>a</td><td>b</td></tr>" +
+        "<tr><td>c</td><td>d</td></tr>" +
+        "</tbody></table>",
+    );
+    normalizeTableColumnWidths(container);
+    const rows = container.querySelectorAll("tr");
+    expect(
+      Array.from(rows[1].children).map((c) => c.getAttribute("colwidth")),
+    ).toEqual([null, null]);
+  });
+});

apps/client/src/features/editor/extensions/markdown-clipboard.ts

@@ -3,7 +3,14 @@ import { Extension } from "@tiptap/core";
 import { Plugin, PluginKey, TextSelection } from "@tiptap/pm/state";
 import { DOMParser, DOMSerializer, Fragment, Slice } from "@tiptap/pm/model";
 import { find } from "linkifyjs";
-import { markdownToHtml, htmlToMarkdown } from "@docmost/editor-ext";
+import {
+  markdownToHtml,
+  htmlToMarkdown,
+  canonicalizeFootnotes,
+  FOOTNOTES_LIST_NAME,
+  FOOTNOTE_REFERENCE_NAME,
+} from "@docmost/editor-ext";
+import type { Schema } from "@tiptap/pm/model";
 
 export const MarkdownClipboard = Extension.create({
   name: "markdownClipboard",
@@ -83,12 +90,25 @@ export const MarkdownClipboard = Extension.create({
             const body = elementFromString(parsed);
             normalizeTableColumnWidths(body);
 
-            const contentNodes = DOMParser.fromSchema(
+            const parsedSlice = DOMParser.fromSchema(
               this.editor.schema,
             ).parseSlice(body, {
               preserveWhitespace: true,
             });
 
+            // A markdown paste builds its ProseMirror fragment directly (DOM ->
+            // parseSlice), bypassing the editor's footnoteSyncPlugin, which never
+            // reorders an existing list. So a pasted markdown block whose footnote
+            // definitions are out of order (or contains orphan defs) would be
+            // stored out of order. Canonicalize the self-contained pasted block so
+            // its footnotes come out reference-ordered, deduped and orphan-free
+            // (issue #228). See canonicalizePastedFootnotes for why this is scoped
+            // to whole-block pastes that carry their own footnotesList.
+            const contentNodes = canonicalizePastedFootnotes(
+              parsedSlice,
+              this.editor.schema,
+            );
+
             tr.replaceRange(from, to, contentNodes);
             const insertEnd = tr.mapping.map(from, 1);
             tr.setSelection(TextSelection.near(tr.doc.resolve(Math.max(from, insertEnd - 2)), -1));
@@ -133,6 +153,54 @@ export const MarkdownClipboard = Extension.create({
   },
 });
 
+/**
+ * Reorder/dedup the footnotes of a SELF-CONTAINED pasted markdown block to the
+ * canonical invariant (the live footnoteSyncPlugin never reorders an existing
+ * list, so an out-of-order pasted block would otherwise persist out of order).
+ *
+ * Scoped deliberately to whole-block pastes (openStart/openEnd === 0) that carry
+ * their OWN footnotesList: canonicalizeFootnotes would synthesize empty
+ * definitions for any reference lacking a definition, which is correct for a
+ * standalone block but would be wrong for a reference-only paste that REUSES a
+ * footnote already defined in the target document — so those are left untouched
+ * for the paste/sync plugins to merge. Residual: when the pasted block is merged
+ * into a doc that already has footnotes, ordering RELATIVE to the pre-existing
+ * footnotes is still governed by the sync plugin (which does not reorder).
+ *
+ * Also requires at least one footnoteReference in the selection: a definitions-ONLY
+ * paste (`[^a]: …` with no `[^a]` reference in the same block) has no references,
+ * so canonicalizeFootnotes would drop the whole list and the paste would come out
+ * EMPTY — losing the pasted text. Such a block is left as-is for the sync plugin.
+ */
+export function canonicalizePastedFootnotes(slice: Slice, schema: Schema): Slice {
+  if (slice.openStart !== 0 || slice.openEnd !== 0) return slice;
+
+  let hasFootnotesList = false;
+  let hasReference = false;
+  slice.content.forEach((node) => {
+    if (node.type.name === FOOTNOTES_LIST_NAME) hasFootnotesList = true;
+    // footnoteReference is an inline atom, never a top-level slice child here
+    // (this function early-returns for open slices, so children are whole
+    // blocks), so it is only reachable by descending.
+    node.descendants((child) => {
+      if (child.type.name === FOOTNOTE_REFERENCE_NAME) hasReference = true;
+    });
+  });
+  if (!hasFootnotesList) return slice;
+  // No reference anywhere -> a definitions-only paste; canonicalizing would strip
+  // the reference-less list (empty paste). Leave it untouched.
+  if (!hasReference) return slice;
+
+  const content = slice.content.toJSON();
+  if (!Array.isArray(content)) return slice;
+
+  const canonical = canonicalizeFootnotes({ type: "doc", content }) as {
+    content?: unknown[];
+  };
+  const fragment = Fragment.fromJSON(schema, canonical.content ?? []);
+  return new Slice(fragment, 0, 0);
+}
+
 function elementFromString(value) {
   // add a wrapper to preserve leading and trailing whitespace
   const wrappedValue = `<body>${value}</body>`;

apps/client/src/features/editor/page-editor.tsx

@@ -84,6 +84,10 @@ import { PageEmbedLookupProvider } from "@/features/editor/components/page-embed
 import { PageEmbedAncestryProvider } from "@/features/editor/components/page-embed/page-embed-ancestry-context";
 import PageEmbedPicker from "@/features/editor/components/page-embed/page-embed-picker";
 import { useTranslation } from "react-i18next";
+import {
+  isBodyEditable,
+  isCollabSynced,
+} from "@/features/editor/editor-sync-state";
 
 interface PageEditorProps {
   pageId: string;
@@ -440,6 +444,9 @@ export default function PageEditor({
 
   const isSynced = isLocalSynced && isRemoteSynced;
 
+  const hasConnectedOnceRef = useRef(false);
+  const [showStatic, setShowStatic] = useState(true);
+
   useEffect(() => {
     const timeout = setTimeout(() => {
       if (yjsConnectionStatus === WebSocketStatus.Connecting || !isSynced) {
@@ -451,17 +458,21 @@ export default function PageEditor({
   }, [yjsConnectionStatus, isSynced]);
   useEffect(() => {
     if (!editor) return;
-    editor.setEditable(editable && currentPageEditMode === PageEditMode.Edit);
-  }, [currentPageEditMode, editor, editable]);
-
-  const hasConnectedOnceRef = useRef(false);
-  const [showStatic, setShowStatic] = useState(true);
+    // Keep the body read-only until the collab doc has synced (showStatic), so
+    // early keystrokes on a freshly created page can't be lost (#218).
+    editor.setEditable(
+      isBodyEditable({
+        editable,
+        inEditMode: currentPageEditMode === PageEditMode.Edit,
+        showStatic,
+      }),
+    );
+  }, [currentPageEditMode, editor, editable, showStatic]);
 
   useEffect(() => {
     if (
       !hasConnectedOnceRef.current &&
-      yjsConnectionStatus === WebSocketStatus.Connected &&
-      isSynced
+      isCollabSynced(yjsConnectionStatus, isSynced)
     ) {
       hasConnectedOnceRef.current = true;
       setShowStatic(false);
@@ -473,17 +484,43 @@ export default function PageEditor({
       <PageEmbedLookupProvider>
         <PageEmbedAncestryProvider hostPageId={pageId}>
       {showStatic ? (
-        <EditorProvider
-          editable={false}
-          immediatelyRender={true}
-          extensions={mainExtensions}
-          content={content}
-          editorProps={{
-            attributes: {
-              "aria-label": t("Page content"),
-            },
-          }}
-        />
+        <div style={{ position: "relative" }}>
+          {/* Surface the pre-sync read-only window so edits typed before the
+              collab provider connects aren't silently swallowed (#218). Shown
+              only when the user is otherwise allowed to edit. */}
+          {editable && currentPageEditMode === PageEditMode.Edit && (
+            <div
+              role="status"
+              aria-live="polite"
+              className="print-hide"
+              style={{
+                position: "absolute",
+                top: 0,
+                right: 0,
+                zIndex: 2,
+                padding: "2px 8px",
+                fontSize: "12px",
+                borderRadius: "4px",
+                background: "var(--mantine-color-gray-light)",
+                color: "var(--mantine-color-dimmed)",
+                pointerEvents: "none",
+              }}
+            >
+              {t("Connecting… (read-only)")}
+            </div>
+          )}
+          <EditorProvider
+            editable={false}
+            immediatelyRender={true}
+            extensions={mainExtensions}
+            content={content}
+            editorProps={{
+              attributes: {
+                "aria-label": t("Page content"),
+              },
+            }}
+          />
+        </div>
       ) : (
         <div className="editor-container" style={{ position: "relative" }}>
           <div ref={menuContainerRef}>

apps/client/src/features/page-history/components/history-item.test.tsx

@@ -0,0 +1,227 @@
+import { describe, it, expect, vi, afterEach, beforeAll } from "vitest";
+import { render, screen, cleanup, within } from "@testing-library/react";
+import { MantineProvider } from "@mantine/core";
+
+// Mantine Tooltip mounts its label lazily on hover via Floating UI, which is
+// flaky under jsdom. Replace ONLY the Tooltip with a thin wrapper that renders
+// the label inline (keeping Badge/Switch/etc. real), so the provenance label —
+// the contract we care about — is deterministically queryable.
+vi.mock("@mantine/core", async () => {
+  const actual =
+    await vi.importActual<typeof import("@mantine/core")>("@mantine/core");
+  const Tooltip = ({
+    label,
+    children,
+  }: {
+    label?: React.ReactNode;
+    children?: React.ReactNode;
+  }) => (
+    <>
+      {children}
+      <span data-testid="tooltip-label">{label}</span>
+    </>
+  );
+  Tooltip.Group = ({ children }: { children?: React.ReactNode }) => (
+    <>{children}</>
+  );
+  return { ...actual, Tooltip };
+});
+
+// jsdom lacks matchMedia, which MantineProvider's color-scheme hook needs.
+beforeAll(() => {
+  if (!window.matchMedia) {
+    window.matchMedia = (query: string) =>
+      ({
+        matches: false,
+        media: query,
+        onchange: null,
+        addListener: () => {},
+        removeListener: () => {},
+        addEventListener: () => {},
+        removeEventListener: () => {},
+        dispatchEvent: () => false,
+      }) as unknown as MediaQueryList;
+  }
+});
+
+// --- Mocks for the heavy / networked module graph ---------------------------
+// HistoryItem pulls in i18n, jotai atoms (ai-chat / history), a config-backed
+// avatar and a time formatter. The provenance-badge contract is the unit under
+// test, so we stub everything else down to inert, deterministic renders and
+// keep the real Mantine Badge/Tooltip so role/label queries are meaningful.
+
+// i18n: interpolate {{name}} so the git-sync tooltip carries the author name,
+// letting us assert provenance attribution without a real i18n backend.
+vi.mock("react-i18next", () => ({
+  useTranslation: () => ({
+    t: (key: string, vars?: Record<string, unknown>) =>
+      vars && typeof vars.name !== "undefined"
+        ? key.replace("{{name}}", String(vars.name))
+        : key,
+  }),
+}));
+
+// jotai setters: the badges call useSetAtom; return inert setters so a click on
+// the (deep-linkable) AiAgentBadge would fire these — proving the git-sync badge
+// does NOT wire any of them.
+const setAiChatWindowOpen = vi.fn();
+const setActiveChatId = vi.fn();
+const setDraft = vi.fn();
+const setHistoryModalOpen = vi.fn();
+vi.mock("jotai", async () => {
+  const actual = await vi.importActual<typeof import("jotai")>("jotai");
+  return {
+    ...actual,
+    useSetAtom: (atom: unknown) => {
+      switch (atom) {
+        case aiChatWindowOpenAtom:
+          return setAiChatWindowOpen;
+        case activeAiChatIdAtom:
+          return setActiveChatId;
+        case aiChatDraftAtom:
+          return setDraft;
+        case historyAtoms:
+          return setHistoryModalOpen;
+        default:
+          return vi.fn();
+      }
+    },
+  };
+});
+
+// Atoms are imported only as identity tokens for the useSetAtom switch above.
+vi.mock("@/features/ai-chat/atoms/ai-chat-atom.ts", () => ({
+  activeAiChatIdAtom: { __tag: "activeAiChatIdAtom" },
+  aiChatWindowOpenAtom: { __tag: "aiChatWindowOpenAtom" },
+  aiChatDraftAtom: { __tag: "aiChatDraftAtom" },
+}));
+vi.mock("@/features/page-history/atoms/history-atoms.ts", () => ({
+  historyAtoms: { __tag: "historyAtoms" },
+}));
+
+// Avatar reaches into config (getAvatarUrl) — stub to a plain element.
+vi.mock("@/components/ui/custom-avatar.tsx", () => ({
+  CustomAvatar: ({ name }: { name?: string }) => (
+    <span data-testid="avatar">{name}</span>
+  ),
+}));
+
+// Deterministic, locale-free date string.
+vi.mock("@/lib/time", () => ({
+  formattedDate: () => "2026-06-21",
+}));
+
+import HistoryItem from "./history-item";
+import {
+  activeAiChatIdAtom,
+  aiChatWindowOpenAtom,
+  aiChatDraftAtom,
+} from "@/features/ai-chat/atoms/ai-chat-atom.ts";
+import { historyAtoms } from "@/features/page-history/atoms/history-atoms.ts";
+import type { IPageHistory } from "@/features/page-history/types/page.types";
+
+function makeItem(overrides: Partial<IPageHistory> = {}): IPageHistory {
+  return {
+    id: "h1",
+    pageId: "p1",
+    title: "Title",
+    slug: "slug",
+    icon: "",
+    coverPhoto: "",
+    version: 1,
+    lastUpdatedById: "u1",
+    workspaceId: "w1",
+    createdAt: "2026-06-21T00:00:00.000Z",
+    updatedAt: "2026-06-21T00:00:00.000Z",
+    lastUpdatedBy: { id: "u1", name: "Alice", avatarUrl: "" },
+    ...overrides,
+  };
+}
+
+function renderItem(item: IPageHistory) {
+  return render(
+    <MantineProvider>
+      <HistoryItem
+        historyItem={item}
+        index={0}
+        onSelect={vi.fn()}
+        isActive={false}
+      />
+    </MantineProvider>,
+  );
+}
+
+afterEach(() => {
+  cleanup();
+  vi.clearAllMocks();
+});
+
+describe("HistoryItem git-sync provenance badge", () => {
+  // Test 1: the git-sync badge renders ONLY for lastUpdatedSource === 'git-sync'.
+  it("renders the Git sync badge only when lastUpdatedSource is 'git-sync'", () => {
+    renderItem(makeItem({ lastUpdatedSource: "git-sync" }));
+    expect(screen.getByText("Git sync")).toBeTruthy();
+  });
+
+  it.each([
+    ["agent", "agent"],
+    ["user", "user"],
+    ["undefined", undefined],
+  ])(
+    "does NOT render the Git sync badge when lastUpdatedSource is %s",
+    (_label, source) => {
+      renderItem(makeItem({ lastUpdatedSource: source }));
+      expect(screen.queryByText("Git sync")).toBeNull();
+    },
+  );
+
+  // Test 2: provenance attribution + the git-sync badge is NOT interactive.
+  it("attributes the git-sync provenance to the correct author and is not clickable", () => {
+    renderItem(
+      makeItem({
+        lastUpdatedSource: "git-sync",
+        lastUpdatedBy: { id: "u2", name: "Bob", avatarUrl: "" },
+      }),
+    );
+
+    const badge = screen.getByText("Git sync");
+
+    // Provenance attribution: the tooltip label carries the author name (the
+    // git-sync badge passes authorName -> "Synced from Git on behalf of {{name}}").
+    expect(screen.getByText("Synced from Git on behalf of Bob")).toBeTruthy();
+
+    // The git-sync badge must NOT behave like AiAgentBadge: the badge element
+    // itself is not a button, carries no role=button and no tabIndex, and
+    // clicking it must not trigger any ai-chat deep-link. (The surrounding
+    // history-row IS an UnstyledButton — that is the row's own select affordance,
+    // not the badge — so we scope these checks to the badge element.)
+    const badgeRoot = (badge.closest("[class*='mantine-Badge-root']") ??
+      badge) as HTMLElement;
+    expect(badgeRoot.getAttribute("role")).not.toBe("button");
+    expect(badgeRoot.getAttribute("tabindex")).toBeNull();
+    expect(badgeRoot.tagName.toLowerCase()).not.toBe("button");
+    // No interactive descendant button lives inside the badge itself.
+    expect(within(badgeRoot).queryByRole("button")).toBeNull();
+
+    badgeRoot.dispatchEvent(new MouseEvent("click", { bubbles: true }));
+    expect(setActiveChatId).not.toHaveBeenCalled();
+    expect(setAiChatWindowOpen).not.toHaveBeenCalled();
+    expect(setDraft).not.toHaveBeenCalled();
+    expect(setHistoryModalOpen).not.toHaveBeenCalled();
+  });
+
+  // Sanity contrast: the agent badge (the copy-paste source) IS interactive when
+  // it carries an aiChatId — proving the not-clickable assertion above is real.
+  it("contrast: the AI-agent badge is a deep-link button when it has an aiChatId", () => {
+    renderItem(
+      makeItem({
+        lastUpdatedSource: "agent",
+        lastUpdatedAiChatId: "chat-1",
+      }),
+    );
+    const agentBadge = screen.getByText("AI-agent");
+    const root = agentBadge.closest("[role='button']");
+    expect(root).not.toBeNull();
+    within(root as HTMLElement).getByText("AI-agent");
+  });
+});

apps/client/src/features/page-history/components/history-item.tsx

@@ -1,6 +1,7 @@
 import { Text, Group, UnstyledButton, Avatar, Tooltip } from "@mantine/core";
 import { CustomAvatar } from "@/components/ui/custom-avatar.tsx";
 import { AiAgentBadge } from "@/components/ui/ai-agent-badge.tsx";
+import { GitSyncBadge } from "@/components/ui/git-sync-badge.tsx";
 import { formattedDate } from "@/lib/time";
 import classes from "./css/history.module.css";
 import clsx from "clsx";
@@ -41,6 +42,7 @@ const HistoryItem = memo(function HistoryItem({
   const contributors = historyItem.contributors;
   const hasContributors = contributors && contributors.length > 0;
   const isAgentEdit = historyItem.lastUpdatedSource === "agent";
+  const isGitSyncEdit = historyItem.lastUpdatedSource === "git-sync";
 
   return (
     <UnstyledButton
@@ -108,6 +110,10 @@ const HistoryItem = memo(function HistoryItem({
             onActivate={() => setHistoryModalOpen(false)}
           />
         )}
+
+        {isGitSyncEdit && (
+          <GitSyncBadge authorName={historyItem.lastUpdatedBy?.name} />
+        )}
       </Group>
     </UnstyledButton>
   );

apps/client/src/features/page/components/breadcrumbs/breadcrumb.tsx

@@ -1,7 +1,7 @@
 import { useAtomValue } from "jotai";
 import { treeDataAtom } from "@/features/page/tree/atoms/tree-data-atom.ts";
 import React, { useCallback, useEffect, useState } from "react";
-import { findBreadcrumbPath } from "@/features/page/tree/utils";
+import { computeBreadcrumbState } from "./breadcrumb.utils";
 import {
   Button,
   Anchor,
@@ -15,8 +15,12 @@ import { IconCornerDownRightDouble, IconDots } from "@tabler/icons-react";
 import { Link, useParams } from "react-router-dom";
 import classes from "./breadcrumb.module.css";
 import { SpaceTreeNode } from "@/features/page/tree/types.ts";
+import { IPage } from "@/features/page/types/page.types.ts";
 import { buildPageUrl } from "@/features/page/page.utils.ts";
-import { usePageQuery } from "@/features/page/queries/page-query.ts";
+import {
+  usePageQuery,
+  usePageBreadcrumbsQuery,
+} from "@/features/page/queries/page-query.ts";
 import { extractPageSlugId } from "@/lib";
 import { useMediaQuery } from "@mantine/hooks";
 import { useTranslation } from "react-i18next";
@@ -38,14 +42,29 @@ export default function Breadcrumb() {
   const { data: currentPage } = usePageQuery({
     pageId: extractPageSlugId(pageSlug),
   });
+  // The page's own ancestor chain, fetched independently of the lazily-built
+  // sidebar tree so a deep page doesn't render a blank breadcrumb for seconds
+  // while the tree backfills (#218).
+  const { data: ancestors } = usePageBreadcrumbsQuery(currentPage?.id);
   const isMobile = useMediaQuery("(max-width: 48em)");
 
   useEffect(() => {
-    if (treeData?.length > 0 && currentPage) {
-      const breadcrumb = findBreadcrumbPath(treeData, currentPage.id);
-      setBreadcrumbNodes(breadcrumb || null);
-    }
-  }, [currentPage?.id, treeData]);
+    if (!currentPage) return;
+
+    // Selection/mapping + stale-clearing live in a pure, unit-tested helper
+    // (#218). It resolves the correct chain when possible and, on a transient
+    // miss, clears a chain left over from a previously-viewed page instead of
+    // showing the wrong trail — while keeping a chain already resolved for THIS
+    // page to avoid a blank flash.
+    setBreadcrumbNodes((previous) =>
+      computeBreadcrumbState(
+        treeData,
+        ancestors as IPage[] | undefined,
+        currentPage.id,
+        previous,
+      ),
+    );
+  }, [currentPage?.id, treeData, ancestors]);
 
   const HiddenNodesTooltipContent = () =>
     breadcrumbNodes?.slice(1, -1).map((node) => (

apps/client/src/features/page/components/breadcrumbs/breadcrumb.utils.test.ts

@@ -0,0 +1,114 @@
+import { describe, it, expect } from "vitest";
+import {
+  computeBreadcrumbState,
+  resolveBreadcrumbNodes,
+} from "./breadcrumb.utils";
+import { SpaceTreeNode } from "@/features/page/tree/types.ts";
+import { IPage } from "@/features/page/types/page.types.ts";
+
+// Pure selection/mapping behind the breadcrumb (#218): tree-hit prefers the live
+// sidebar tree, tree-miss maps the page's own ancestors, and "no data" returns
+// null so the component keeps its prior state.
+
+function treeNode(id: string, over?: Partial<SpaceTreeNode>): SpaceTreeNode {
+  return {
+    id,
+    slugId: `slug-${id}`,
+    name: `node-${id}`,
+    icon: null,
+    position: "a",
+    hasChildren: false,
+    spaceId: "space-1",
+    parentPageId: null,
+    children: [],
+    ...over,
+  } as SpaceTreeNode;
+}
+
+function ancestorPage(id: string, over?: Partial<IPage>): IPage {
+  return {
+    id,
+    slugId: `slug-${id}`,
+    title: `title-${id}`,
+    icon: "📄",
+    position: "m",
+    spaceId: "space-1",
+    parentPageId: null,
+    hasChildren: true,
+    ...over,
+  } as IPage;
+}
+
+describe("resolveBreadcrumbNodes", () => {
+  it("tree-hit: returns the path found in the live sidebar tree", () => {
+    const child = treeNode("child");
+    const root = treeNode("root", { hasChildren: true, children: [child] });
+    // findBreadcrumbPath walks the tree; the chain ends at the target page.
+    const result = resolveBreadcrumbNodes([root], [ancestorPage("child")], "child");
+
+    expect(result).not.toBeNull();
+    expect(result!.map((n) => n.id)).toEqual(["root", "child"]);
+    // Came from the tree, NOT the ancestor mapping (icon stays the tree's null).
+    expect(result![result!.length - 1].icon).toBeNull();
+  });
+
+  it("tree-miss: maps the page's own ancestors (title->name, hasChildren default)", () => {
+    // Tree has no node for the target page -> findBreadcrumbPath misses.
+    const unrelated = treeNode("unrelated");
+    const ancestors = [
+      ancestorPage("a", { hasChildren: true }),
+      ancestorPage("b", { hasChildren: undefined as any }),
+    ];
+
+    const result = resolveBreadcrumbNodes([unrelated], ancestors, "missing-page");
+
+    expect(result).not.toBeNull();
+    expect(result!.map((n) => n.id)).toEqual(["a", "b"]);
+    // Non-trivial field transform: title -> name.
+    expect(result![0].name).toBe("title-a");
+    // hasChildren defaults to false when the ancestor row omits it.
+    expect(result![1].hasChildren).toBe(false);
+    expect(result![0].hasChildren).toBe(true);
+  });
+
+  it("falls back to ancestors when the tree is empty", () => {
+    const result = resolveBreadcrumbNodes([], [ancestorPage("a")], "a");
+    expect(result!.map((n) => n.id)).toEqual(["a"]);
+  });
+
+  it("returns null when there is no tree hit and no ancestor data", () => {
+    expect(resolveBreadcrumbNodes([], [], "x")).toBeNull();
+    expect(resolveBreadcrumbNodes(undefined, undefined, "x")).toBeNull();
+    expect(resolveBreadcrumbNodes(null, null, "x")).toBeNull();
+  });
+});
+
+describe("computeBreadcrumbState (stale-chain clearing on navigation)", () => {
+  it("uses a freshly resolved chain when available", () => {
+    const child = treeNode("B");
+    const root = treeNode("root", { hasChildren: true, children: [child] });
+    const next = computeBreadcrumbState([root], null, "B", null);
+    expect(next!.map((n) => n.id)).toEqual(["root", "B"]);
+  });
+
+  it("navigating A->B to a page absent from treeData clears the previous A chain (no stale trail)", () => {
+    // Previous chain ends at page A; we are now on page B, which is not yet in
+    // the lazily-built tree and whose ancestors have not loaded.
+    const previous = [treeNode("rootA"), treeNode("A")];
+    const next = computeBreadcrumbState([treeNode("unrelated")], undefined, "B", previous);
+    // Must NOT keep showing A's (clickable) chain.
+    expect(next).toBeNull();
+  });
+
+  it("keeps a chain that already ends at the current page through a transient miss", () => {
+    // We already resolved B once (chain ends at B); a transient miss must not
+    // blank it.
+    const previous = [treeNode("rootB"), treeNode("B")];
+    const next = computeBreadcrumbState([], undefined, "B", previous);
+    expect(next).toBe(previous);
+  });
+
+  it("returns null when nothing resolves and there is no previous chain", () => {
+    expect(computeBreadcrumbState([], undefined, "B", null)).toBeNull();
+  });
+});

apps/client/src/features/page/components/breadcrumbs/breadcrumb.utils.ts

@@ -0,0 +1,61 @@
+import { IPage } from "@/features/page/types/page.types.ts";
+import { SpaceTreeNode } from "@/features/page/tree/types.ts";
+import { findBreadcrumbPath, pageToTreeNode } from "@/features/page/tree/utils";
+
+/**
+ * Pure selection/mapping for the breadcrumb nodes (#218). Three branches:
+ *   1. tree-hit  — the lazily-built sidebar tree already contains this page's
+ *      ancestor chain, so prefer it (stays live with sidebar renames/moves).
+ *   2. tree-miss — fall back to the page's own ancestor data so a deep page
+ *      resolves immediately instead of rendering a blank breadcrumb for seconds
+ *      while the tree backfills. Mapped through the canonical `pageToTreeNode`
+ *      (title -> name, hasChildren defaulted to false).
+ *   3. neither   — no data yet, return null (the caller decides whether to keep
+ *      a prior chain via computeBreadcrumbState).
+ */
+export function resolveBreadcrumbNodes(
+  treeData: SpaceTreeNode[] | null | undefined,
+  ancestors: IPage[] | null | undefined,
+  pageId: string,
+): SpaceTreeNode[] | null {
+  if (treeData && treeData.length > 0) {
+    const breadcrumb = findBreadcrumbPath(treeData, pageId);
+    if (breadcrumb) {
+      return breadcrumb;
+    }
+  }
+
+  if (ancestors && ancestors.length > 0) {
+    return ancestors.map((page) =>
+      pageToTreeNode(page, { hasChildren: page.hasChildren ?? false }),
+    );
+  }
+
+  return null;
+}
+
+/**
+ * Decide the next breadcrumb state, given the previous one. When a chain
+ * resolves (#218) it always wins. When nothing resolves yet, a stale chain from
+ * a previously-viewed page must be CLEARED rather than left showing the wrong,
+ * clickable trail (the reverse regression of the original blank-breadcrumb fix
+ * when navigating A -> B to a deep page not yet in the lazily-built tree). The
+ * one chain we keep through a transient miss is one that already ends at the
+ * current page — that means we already resolved THIS page, so keeping it avoids
+ * a needless blank flash without ever showing the previous page's chain.
+ */
+export function computeBreadcrumbState(
+  treeData: SpaceTreeNode[] | null | undefined,
+  ancestors: IPage[] | null | undefined,
+  pageId: string,
+  previous: SpaceTreeNode[] | null,
+): SpaceTreeNode[] | null {
+  const resolved = resolveBreadcrumbNodes(treeData, ancestors, pageId);
+  if (resolved) {
+    return resolved;
+  }
+
+  const previousEndsAtCurrentPage =
+    previous != null && previous[previous.length - 1]?.id === pageId;
+  return previousEndsAtCurrentPage ? previous : null;
+}

apps/client/src/features/share/components/share-modal.test.tsx

@@ -0,0 +1,74 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { render, screen, fireEvent, waitFor } from "@testing-library/react";
+import { MantineProvider } from "@mantine/core";
+import { MemoryRouter } from "react-router-dom";
+
+// matchMedia / storage are stubbed globally in vitest.setup.ts.
+
+// Enabling a public share must NOT silently expose the whole sub-tree (#216):
+// the create call defaults includeSubPages to false. This was a one-literal,
+// security-relevant default with no test — lock it.
+
+const createMutateAsync = vi.fn(async () => ({}));
+const deleteMutateAsync = vi.fn(async () => ({}));
+
+// No existing share for this page (toggle starts OFF).
+let shareData: any = undefined;
+
+vi.mock("react-i18next", () => ({
+  useTranslation: () => ({ t: (key: string) => key }),
+}));
+
+vi.mock("@/features/share/queries/share-query.ts", () => ({
+  useCreateShareMutation: () => ({ mutateAsync: createMutateAsync }),
+  useDeleteShareMutation: () => ({ mutateAsync: deleteMutateAsync }),
+  useUpdateShareMutation: () => ({ mutateAsync: vi.fn() }),
+  useShareForPageQuery: () => ({ data: shareData }),
+}));
+
+vi.mock("@/features/page/queries/page-query.ts", () => ({
+  usePageQuery: () => ({ data: { id: "page-1", title: "Doc" } }),
+}));
+
+vi.mock("@/features/space/queries/space-query.ts", () => ({
+  useSpaceQuery: () => ({ data: { settings: {} } }),
+}));
+
+import ShareModal from "./share-modal";
+
+function renderModal() {
+  return render(
+    <MemoryRouter>
+      <MantineProvider>
+        <ShareModal readOnly={false} />
+      </MantineProvider>
+    </MemoryRouter>,
+  );
+}
+
+describe("ShareModal — enabling a share defaults includeSubPages to false (#216)", () => {
+  beforeEach(() => {
+    createMutateAsync.mockClear();
+    deleteMutateAsync.mockClear();
+    shareData = undefined;
+  });
+
+  it("creates the share with includeSubPages: false when the user turns it on", async () => {
+    renderModal();
+
+    // Open the share popover.
+    fireEvent.click(screen.getByRole("button", { name: "Share" }));
+
+    // The "Share to web" toggle is the only switch in the not-yet-shared state.
+    const toggle = await screen.findByRole("switch");
+    fireEvent.click(toggle);
+
+    await waitFor(() => expect(createMutateAsync).toHaveBeenCalledTimes(1));
+    expect(createMutateAsync).toHaveBeenCalledWith(
+      expect.objectContaining({
+        pageId: "page-1",
+        includeSubPages: false,
+      }),
+    );
+  });
+});

apps/client/src/features/share/components/share-modal.tsx

@@ -73,7 +73,10 @@ export default function ShareModal({ readOnly }: ShareModalProps) {
       if (value) {
         await createShareMutation.mutateAsync({
           pageId: pageId,
-          includeSubPages: true,
+          // Opt-in: enabling a share must NOT silently expose the whole
+          // sub-tree (#216). Sub-pages are shared only when the user turns on
+          // the dedicated "Include sub-pages" toggle.
+          includeSubPages: false,
           searchIndexing: false,
         });
       } else if (share && share.id) {

apps/client/src/features/share/types/share.types.ts

@@ -35,9 +35,17 @@ export interface ISharedItem extends IShare {
   };
 }
 
-export interface ISharedPage extends IShare {
-  page: IPage;
-  share: IShare & {
+// The `/shares/page-info` (anonymous) response. Mirrors the server-side
+// PublicSharePayload allowlist (#218): the server trims `page`/`share` to these
+// fields exactly, so the client type must not over-declare internal metadata it
+// will never receive. Keep this in sync with share-public-payload.ts.
+export interface ISharedPage {
+  page: Pick<IPage, "id" | "slugId" | "title" | "icon" | "content">;
+  share: {
+    id: string;
+    key: string;
+    includeSubPages: boolean;
+    searchIndexing: boolean;
     level: number;
     sharedPage: { id: string; slugId: string; title: string; icon: string };
   };
@@ -73,6 +81,10 @@ export type IUpdateShare = ICreateShare & { shareId: string; pageId?: string };
 
 export interface IShareInfoInput {
   pageId: string;
+  // The share id/key from the `/share/:shareId/p/:slug` URL. When present the
+  // server binds content access to this exact share (#218): a forged/mismatched
+  // shareId 404s instead of rendering the page off its slug alone.
+  shareId?: string;
 }
 
 // Vanity /l/:alias pointer.

apps/client/src/features/space/components/edit-space-form.test.tsx

@@ -0,0 +1,240 @@
+import {
+  describe,
+  it,
+  expect,
+  vi,
+  beforeAll,
+  afterEach,
+} from "vitest";
+import {
+  render,
+  screen,
+  cleanup,
+  fireEvent,
+  waitFor,
+} from "@testing-library/react";
+import { MantineProvider } from "@mantine/core";
+
+// --- Mocks for the heavy / networked module graph ---------------------------
+// EditSpaceForm wires the "Enable Git sync" Switch to a TanStack-Query mutation
+// (useUpdateSpaceMutation). We mock ONLY that hook so the test fully controls
+// mutateAsync (resolve / reject) and isPending, and stub i18n. The real Mantine
+// Switch is rendered so the checkbox role / disabled state is meaningful.
+
+// i18n: identity translator — labels stay as their English keys for queries.
+vi.mock("react-i18next", () => ({
+  useTranslation: () => ({ t: (key: string) => key }),
+}));
+
+// Mutation hook: a controllable mutateAsync plus a togglable isPending.
+const mutateAsync = vi.fn();
+let isPending = false;
+vi.mock("@/features/space/queries/space-query.ts", () => ({
+  useUpdateSpaceMutation: () => ({
+    mutateAsync,
+    get isPending() {
+      return isPending;
+    },
+  }),
+}));
+
+// jsdom lacks matchMedia, which MantineProvider's color-scheme hook needs.
+beforeAll(() => {
+  if (!window.matchMedia) {
+    window.matchMedia = (query: string) =>
+      ({
+        matches: false,
+        media: query,
+        onchange: null,
+        addListener: () => {},
+        removeListener: () => {},
+        addEventListener: () => {},
+        removeEventListener: () => {},
+        dispatchEvent: () => false,
+      }) as unknown as MediaQueryList;
+  }
+});
+
+import { EditSpaceForm } from "./edit-space-form";
+import type { ISpace } from "@/features/space/types/space.types.ts";
+
+function makeSpace(overrides: Partial<ISpace> = {}): ISpace {
+  return {
+    id: "space-1",
+    name: "Engineering",
+    description: "",
+    slug: "eng",
+    hostname: "host",
+    creatorId: "u1",
+    createdAt: new Date("2026-01-01"),
+    updatedAt: new Date("2026-01-01"),
+    ...overrides,
+  } as ISpace;
+}
+
+function renderForm(props: { space: ISpace; readOnly?: boolean }) {
+  return render(
+    <MantineProvider>
+      <EditSpaceForm space={props.space} readOnly={props.readOnly} />
+    </MantineProvider>,
+  );
+}
+
+// The form now renders TWO switches (git-sync enable + auto-merge-conflicts) in
+// that DOM order. Mantine renders each as an <input type="checkbox"
+// role="switch"> but does NOT expose its label as the accessible name, so we
+// disambiguate by DOM order (index 0 = enable, 1 = auto-merge) and assert the
+// human-readable label text is present alongside.
+function getToggle(): HTMLInputElement {
+  screen.getByText("Enable Git sync");
+  return screen.getAllByRole("switch")[0] as HTMLInputElement;
+}
+
+function getAutoMergeToggle(): HTMLInputElement {
+  screen.getByText("Auto-merge conflicts on push");
+  return screen.getAllByRole("switch")[1] as HTMLInputElement;
+}
+
+afterEach(() => {
+  cleanup();
+  mutateAsync.mockReset();
+  isPending = false;
+});
+
+describe("EditSpaceForm git-sync toggle", () => {
+  // Test 3: initial checked state derives from settings.gitSync.enabled ?? false.
+  it("derives initial checked state from space.settings.gitSync.enabled (true -> checked)", () => {
+    renderForm({
+      space: makeSpace({ settings: { gitSync: { enabled: true } } }),
+    });
+    expect(getToggle().checked).toBe(true);
+  });
+
+  it("defaults to unchecked when gitSync settings are missing", () => {
+    renderForm({ space: makeSpace() });
+    expect(getToggle().checked).toBe(false);
+  });
+
+  // Test 4: toggling fires the mutation with { spaceId, gitSyncEnabled } and
+  // optimistically flips the switch.
+  it("fires the mutation with the correct payload and optimistically flips on", async () => {
+    mutateAsync.mockResolvedValue(undefined);
+    renderForm({ space: makeSpace() });
+
+    const toggle = getToggle();
+    expect(toggle.checked).toBe(false);
+
+    fireEvent.click(toggle);
+
+    // Optimistic update: the switch reflects the new state immediately.
+    expect(toggle.checked).toBe(true);
+
+    expect(mutateAsync).toHaveBeenCalledTimes(1);
+    expect(mutateAsync).toHaveBeenCalledWith({
+      spaceId: "space-1",
+      gitSyncEnabled: true,
+    });
+
+    // Resolution leaves the toggle on.
+    await waitFor(() => expect(toggle.checked).toBe(true));
+  });
+
+  // Test 5: rollback on mutation error — the most valuable test.
+  it("rolls back the toggle to its prior state when the mutation rejects", async () => {
+    mutateAsync.mockRejectedValue(new Error("network"));
+    renderForm({
+      space: makeSpace({ settings: { gitSync: { enabled: false } } }),
+    });
+
+    const toggle = getToggle();
+    expect(toggle.checked).toBe(false);
+
+    fireEvent.click(toggle);
+
+    // Optimistically flips on before the rejection lands.
+    expect(toggle.checked).toBe(true);
+    expect(mutateAsync).toHaveBeenCalledWith({
+      spaceId: "space-1",
+      gitSyncEnabled: true,
+    });
+
+    // After the rejected promise settles, the component reverts to OFF so the
+    // user is not misled into believing sync is enabled.
+    await waitFor(() => expect(toggle.checked).toBe(false));
+  });
+
+  // Test 6: disabled when readOnly and when the mutation is pending.
+  it("disables the toggle when readOnly", () => {
+    renderForm({ space: makeSpace(), readOnly: true });
+    expect(getToggle().disabled).toBe(true);
+  });
+
+  it("disables the toggle while the mutation is pending", () => {
+    isPending = true;
+    renderForm({ space: makeSpace() });
+    expect(getToggle().disabled).toBe(true);
+  });
+});
+
+describe("EditSpaceForm auto-merge-conflicts toggle", () => {
+  it("derives initial checked state from space.settings.gitSync.autoMergeConflicts (true -> checked)", () => {
+    renderForm({
+      space: makeSpace({
+        settings: { gitSync: { autoMergeConflicts: true } },
+      }),
+    });
+    expect(getAutoMergeToggle().checked).toBe(true);
+  });
+
+  it("defaults to unchecked when autoMergeConflicts is missing (SAFE default)", () => {
+    renderForm({ space: makeSpace() });
+    expect(getAutoMergeToggle().checked).toBe(false);
+  });
+
+  it("fires the mutation with { spaceId, autoMergeConflicts } and optimistically flips on", async () => {
+    mutateAsync.mockResolvedValue(undefined);
+    renderForm({ space: makeSpace() });
+
+    const toggle = getAutoMergeToggle();
+    expect(toggle.checked).toBe(false);
+
+    fireEvent.click(toggle);
+
+    // Optimistic update.
+    expect(toggle.checked).toBe(true);
+    expect(mutateAsync).toHaveBeenCalledTimes(1);
+    expect(mutateAsync).toHaveBeenCalledWith({
+      spaceId: "space-1",
+      autoMergeConflicts: true,
+    });
+
+    await waitFor(() => expect(toggle.checked).toBe(true));
+  });
+
+  it("rolls back to its prior state when the mutation rejects", async () => {
+    mutateAsync.mockRejectedValue(new Error("network"));
+    renderForm({
+      space: makeSpace({
+        settings: { gitSync: { autoMergeConflicts: false } },
+      }),
+    });
+
+    const toggle = getAutoMergeToggle();
+    expect(toggle.checked).toBe(false);
+
+    fireEvent.click(toggle);
+
+    expect(toggle.checked).toBe(true);
+    expect(mutateAsync).toHaveBeenCalledWith({
+      spaceId: "space-1",
+      autoMergeConflicts: true,
+    });
+
+    await waitFor(() => expect(toggle.checked).toBe(false));
+  });
+
+  it("disables the toggle when readOnly", () => {
+    renderForm({ space: makeSpace(), readOnly: true });
+    expect(getAutoMergeToggle().disabled).toBe(true);
+  });
+});

apps/client/src/features/space/components/edit-space-form.tsx

@@ -1,5 +1,14 @@
-import { Group, Box, Button, TextInput, Stack, Textarea } from "@mantine/core";
-import React from "react";
+import {
+  Group,
+  Box,
+  Button,
+  TextInput,
+  Stack,
+  Textarea,
+  Divider,
+  Switch,
+} from "@mantine/core";
+import React, { useState } from "react";
 import { useForm } from "@mantine/form";
 import { zod4Resolver } from "mantine-form-zod-resolver";
 import { z } from "zod/v4";
@@ -29,6 +38,37 @@ export function EditSpaceForm({ space, readOnly }: EditSpaceFormProps) {
   const { t } = useTranslation();
   const updateSpaceMutation = useUpdateSpaceMutation();
 
+  const [gitSyncEnabled, setGitSyncEnabled] = useState<boolean>(
+    space?.settings?.gitSync?.enabled ?? false,
+  );
+
+  const [autoMergeConflicts, setAutoMergeConflicts] = useState<boolean>(
+    space?.settings?.gitSync?.autoMergeConflicts ?? false,
+  );
+
+  // One parameterized handler for both git-sync space toggles: they differ only by
+  // the local state setter, the mutation payload field, and the error label. The
+  // update is optimistic and reverts the local state on failure (the mutation
+  // surfaces a toast via onError; the raw error is still logged per AGENTS.md).
+  const handleToggle = async (
+    field: "gitSyncEnabled" | "autoMergeConflicts",
+    value: boolean,
+    previous: boolean,
+    setLocal: (next: boolean) => void,
+    errorLabel: string,
+  ) => {
+    setLocal(value); // optimistic update
+    try {
+      await updateSpaceMutation.mutateAsync({
+        spaceId: space.id,
+        [field]: value,
+      });
+    } catch (err) {
+      setLocal(previous); // revert on failure
+      console.error(errorLabel, err);
+    }
+  };
+
   const form = useForm<FormValues>({
     validate: zod4Resolver(formSchema),
     initialValues: {
@@ -104,6 +144,43 @@ export function EditSpaceForm({ space, readOnly }: EditSpaceFormProps) {
             </Group>
           )}
         </form>
+
+        <Divider my="lg" />
+
+        <Switch
+          label={t("Enable Git sync")}
+          description={t("Sync this space's pages to a Git repository.")}
+          checked={gitSyncEnabled}
+          disabled={readOnly || updateSpaceMutation.isPending}
+          onChange={(event) =>
+            handleToggle(
+              "gitSyncEnabled",
+              event.currentTarget.checked,
+              gitSyncEnabled,
+              setGitSyncEnabled,
+              "Failed to toggle git-sync for space",
+            )
+          }
+        />
+
+        <Switch
+          mt="md"
+          label={t("Auto-merge conflicts on push")}
+          description={t(
+            "When off (recommended), a page whose content still has unresolved Git conflict markers is skipped on push until you resolve the conflict in Git. When on, the markers are stripped and both sides' content is pushed.",
+          )}
+          checked={autoMergeConflicts}
+          disabled={readOnly || updateSpaceMutation.isPending}
+          onChange={(event) =>
+            handleToggle(
+              "autoMergeConflicts",
+              event.currentTarget.checked,
+              autoMergeConflicts,
+              setAutoMergeConflicts,
+              "Failed to toggle git-sync auto-merge-conflicts",
+            )
+          }
+        />
       </Box>
     </>
   );

apps/client/src/features/space/types/space.types.ts

@@ -13,9 +13,15 @@ export interface ISpaceCommentsSettings {
   allowViewerComments?: boolean;
 }
 
+export interface ISpaceGitSyncSettings {
+  enabled?: boolean;
+  autoMergeConflicts?: boolean;
+}
+
 export interface ISpaceSettings {
   sharing?: ISpaceSharingSettings;
   comments?: ISpaceCommentsSettings;
+  gitSync?: ISpaceGitSyncSettings;
 }
 
 export interface ISpace {
@@ -35,6 +41,8 @@ export interface ISpace {
   // for updates
   disablePublicSharing?: boolean;
   allowViewerComments?: boolean;
+  gitSyncEnabled?: boolean;
+  autoMergeConflicts?: boolean;
 }
 
 interface IMembership {

apps/client/src/pages/share/shared-page.tsx

@@ -24,6 +24,9 @@ export default function SharedPage() {
 
   const { data, isLoading, isError, error } = useSharePageQuery({
     pageId: extractPageSlugId(pageSlug),
+    // Forward the URL's shareId so the server binds content to this share
+    // (#218): a forged shareId 404s instead of rendering the page off its slug.
+    shareId,
   });
 
   const sharedTreeData = useAtomValue(sharedTreeDataAtom);

apps/server/package.json

@@ -23,7 +23,7 @@
     "migration:reset": "tsx src/database/migrate.ts down-to NO_MIGRATIONS",
     "migration:codegen": "kysely-codegen --dialect=postgres --camel-case --env-file=../../.env --out-file=./src/database/types/db.d.ts",
     "lint": "eslint \"{src,apps,libs,test}/**/*.ts\" --fix",
-    "pretest": "pnpm --filter @docmost/editor-ext build",
+    "pretest": "pnpm --filter @docmost/editor-ext build && pnpm --filter @docmost/git-sync build && pnpm --filter @docmost/mcp build",
     "test": "jest",
     "test:int": "jest --config test/jest-integration.json",
     "test:watch": "jest --watch",
@@ -41,6 +41,7 @@
     "@aws-sdk/s3-request-presigner": "3.1050.0",
     "@azure/storage-blob": "12.31.0",
     "@clickhouse/client": "^1.18.2",
+    "@docmost/git-sync": "workspace:*",
     "@docmost/mcp": "workspace:*",
     "@docmost/pdf-inspector": "1.9.6",
     "@fastify/cookie": "^11.0.2",
@@ -188,7 +189,12 @@
           ]
         }
       ],
-      "^.+\\.(t|j)sx?$": "ts-jest"
+      "^.+\\.(t|j)sx?$": [
+        "ts-jest",
+        {
+          "isolatedModules": true
+        }
+      ]
     },
     "transformIgnorePatterns": [
       "/node_modules/(?!(\\.pnpm/)?(nanoid|uuid|image-dimensions|marked|happy-dom|lib0)(@|/))"
@@ -198,11 +204,17 @@
     ],
     "coverageDirectory": "../coverage",
     "testEnvironment": "node",
+    "setupFiles": [
+      "<rootDir>/../test/jest.setup.ts"
+    ],
     "moduleNameMapper": {
       "^@docmost/db/(.*)$": "<rootDir>/database/$1",
       "^@docmost/transactional/(.*)$": "<rootDir>/integrations/transactional/$1",
       "^@docmost/ee/(.*)$": "<rootDir>/ee/$1",
-      "^src/(.*)$": "<rootDir>/$1"
+      "^src/(.*)$": "<rootDir>/$1",
+      "^@docmost/git-sync$": "<rootDir>/../../../packages/git-sync/src/index.ts",
+      "^@docmost/git-sync/(.*)$": "<rootDir>/../../../packages/git-sync/src/$1",
+      "^(\\.{1,2}/.*)\\.js$": "$1"
     }
   }
 }

apps/server/src/app.module.ts

@@ -28,6 +28,7 @@ import { ClsModule } from 'nestjs-cls';
 import { NoopAuditModule } from './integrations/audit/audit.module';
 import { ThrottleModule } from './integrations/throttle/throttle.module';
 import { McpModule } from './integrations/mcp/mcp.module';
+import { GitSyncModule } from './integrations/git-sync/git-sync.module';
 import { AiModule } from './integrations/ai/ai.module';
 import { AiChatModule } from './core/ai-chat/ai-chat.module';
 
@@ -89,6 +90,7 @@ try {
     TelemetryModule,
     ThrottleModule,
     McpModule,
+    GitSyncModule,
     AiModule,
     AiChatModule,
     ...enterpriseModules,

apps/server/src/collaboration/collaboration.gateway.ts

@@ -149,6 +149,45 @@ export class CollaborationGateway {
     return this.hocuspocus.openDirectConnection(documentName, context);
   }
 
+  /**
+   * Write a git-originated body into a page, applying the merge on the instance
+   * that OWNS the live Y.Doc so a connected editor CONVERGES on the change.
+   *
+   * git-sync must NOT use openDirectConnection directly for this: that opens the
+   * document on whichever instance/process runs git-sync (the API/worker). When
+   * an editor is connected to a DIFFERENT collab instance/process, that is a
+   * SEPARATE, detached Y.Doc — the merge lands in the detached doc and the DB,
+   * but the live editor never receives the Yjs update; its next debounced
+   * autosave then overwrites the DB with its stale state and SILENTLY REVERTS
+   * the git change (the data-loss bug). Routing through the custom-event channel
+   * runs the merge on the owning instance's shared Document, whose update is
+   * broadcast to every connection (handleUpdate), so the editor's CRDT converges
+   * on the merged result.
+   *
+   * Without redis there is a single instance, so the write runs locally — which
+   * is already the owning (and only) instance the editor is connected to.
+   */
+  async writePageBody(
+    documentName: string,
+    payload: {
+      prosemirrorJson: unknown;
+      baseProsemirrorJson?: unknown;
+      userId: string;
+    },
+  ): Promise<void> {
+    if (this.redisSync) {
+      await this.handleYjsEvent(
+        'gitSyncWriteBody',
+        documentName,
+        payload as any,
+      );
+      return;
+    }
+    await this.collabEventsService
+      .getHandlers(this.hocuspocus)
+      .gitSyncWriteBody(documentName, payload as any);
+  }
+
   /*
    *Can be used before calling openDirectConnection directly
    */

apps/server/src/collaboration/collaboration.handler.git-sync.spec.ts

@@ -0,0 +1,262 @@
+// Exercises the REAL `gitSyncWriteBody` collab handler (the owner-routed body
+// write the data-loss fix introduces). The handler imports the editor graph via
+// collaboration.util / yjs.util (tiptapExtensions -> editor-ext -> react-dom,
+// unloadable under jest's node env, same coupling noted in
+// gitmost-datasource.service.spec.ts), so we stub those + the transformer. The
+// stubbed toYdoc builds paragraph blocks straight from the ProseMirror JSON so
+// we can assert convergence on real text.
+jest.mock('./collaboration.util', () => ({
+  tiptapExtensions: [],
+  getPageId: (name: string) => name.replace(/^page\./, ''),
+  prosemirrorNodeToYElement: jest.fn(),
+}));
+jest.mock('./yjs.util', () => ({
+  setYjsMark: jest.fn(),
+  updateYjsMarkAttribute: jest.fn(),
+}));
+jest.mock('@hocuspocus/transformer', () => {
+  const Yjs = require('yjs');
+  return {
+    TiptapTransformer: {
+      toYdoc: (json: any) => {
+        if (json?.__throw) throw new Error('boom: malformed doc');
+        const d = new Yjs.Doc();
+        const frag = d.getXmlFragment('default');
+        const blocks = (json?.content ?? []).map((node: any) => {
+          const el = new Yjs.XmlElement(node.type || 'paragraph');
+          const text = (node.content ?? [])
+            .map((t: any) => t.text ?? '')
+            .join('');
+          const t = new Yjs.XmlText();
+          if (text) t.insert(0, text);
+          el.insert(0, [t]);
+          return el;
+        });
+        if (blocks.length) frag.insert(0, blocks);
+        return d;
+      },
+    },
+  };
+});
+
+import * as Y from 'yjs';
+import { CollaborationHandler } from './collaboration.handler';
+
+const pmDoc = (...paras: string[]) => ({
+  type: 'doc',
+  content: paras.map((text) => ({
+    type: 'paragraph',
+    content: text ? [{ type: 'text', text }] : [],
+  })),
+});
+
+const texts = (frag: Y.XmlFragment): string[] =>
+  frag.toArray().map((el) =>
+    (el as Y.XmlElement)
+      .toArray()
+      .map((c) => (c as Y.XmlText).toString())
+      .join(''),
+  );
+
+// Build a fake Hocuspocus whose openDirectConnection yields a DirectConnection
+// over a REAL shared Document, with a connected "editor" doc that receives the
+// shared doc's updates (modelling Document.handleUpdate's broadcast on the
+// OWNING instance). Initial content carries live block ids; the editor starts
+// fully synced with the shared doc.
+function fakeHocuspocus(initial: { text: string; id: string }[]) {
+  const shared = new Y.Doc();
+  const frag = shared.getXmlFragment('default');
+  shared.transact(() => {
+    frag.insert(
+      0,
+      initial.map((s) => {
+        const el = new Y.XmlElement('paragraph');
+        el.setAttribute('id', s.id);
+        const t = new Y.XmlText();
+        if (s.text) t.insert(0, s.text);
+        el.insert(0, [t]);
+        return el;
+      }),
+    );
+  });
+  const editor = new Y.Doc();
+  Y.applyUpdate(editor, Y.encodeStateAsUpdate(shared));
+  // Broadcast relay: server-originated updates flow to the connected editor.
+  shared.on('update', (u: Uint8Array, origin: any) => {
+    if (origin !== 'editor') Y.applyUpdate(editor, u, 'server');
+  });
+
+  const openDirectConnection = jest.fn(async () => ({
+    // DirectConnection.transact runs the fn directly against the Document (no
+    // wrapping Y transaction), exactly like @hocuspocus/server.
+    transact: async (fn: (doc: Y.Doc) => void) => fn(shared),
+    disconnect: jest.fn(async () => undefined),
+  }));
+
+  return { hocuspocus: { openDirectConnection } as any, shared, editor };
+}
+
+describe('CollaborationHandler.gitSyncWriteBody (owner-routed body write)', () => {
+  it('converges a connected editor on the git change (no silent revert)', async () => {
+    const { hocuspocus, shared, editor } = fakeHocuspocus([
+      { text: 'alpha', id: 'p1' },
+      { text: 'beta', id: 'p2' },
+    ]);
+    const handler = new CollaborationHandler();
+    const handlers = handler.getHandlers(hocuspocus);
+
+    // git changed block 1 beta -> beta2; base is the pre-change content.
+    await handlers.gitSyncWriteBody('page.x', {
+      prosemirrorJson: pmDoc('alpha', 'beta2'),
+      baseProsemirrorJson: pmDoc('alpha', 'beta'),
+      userId: 'svc-user',
+    });
+
+    // The shared (owning-instance) doc holds the merge...
+    expect(texts(shared.getXmlFragment('default'))).toEqual(['alpha', 'beta2']);
+    // ...and the connected editor CONVERGED via the broadcast (the bug would
+    // leave it on 'beta' and revert the page on its next autosave).
+    expect(texts(editor.getXmlFragment('default'))).toEqual(['alpha', 'beta2']);
+  });
+
+  it('preserves a concurrent edit to a DIFFERENT block (3-way, finding #2)', async () => {
+    const { hocuspocus, shared, editor } = fakeHocuspocus([
+      { text: 'alpha', id: 'p1' },
+      { text: 'beta', id: 'p2' },
+    ]);
+    // The editor is actively editing block 0 while the push arrives.
+    const eFrag = editor.getXmlFragment('default');
+    editor.transact(
+      () => (eFrag.get(0) as Y.XmlElement).get(0) instanceof Y.XmlText &&
+        ((eFrag.get(0) as Y.XmlElement).get(0) as Y.XmlText).insert(5, ' EDIT'),
+      'editor',
+    );
+    Y.applyUpdate(shared, Y.encodeStateAsUpdate(editor), 'editor');
+
+    const handler = new CollaborationHandler();
+    await handler.getHandlers(hocuspocus).gitSyncWriteBody('page.x', {
+      prosemirrorJson: pmDoc('alpha', 'beta2'),
+      baseProsemirrorJson: pmDoc('alpha', 'beta'),
+      userId: 'svc-user',
+    });
+
+    // Human's block-0 edit AND git's block-1 change both survive on the editor.
+    expect(texts(editor.getXmlFragment('default'))).toEqual([
+      'alpha EDIT',
+      'beta2',
+    ]);
+  });
+
+  it('FLUSHES the pending debounced store BEFORE merging so an in-flight edit survives (finding #2)', async () => {
+    // QA #119 finding #2: the 3-way merge must run against the latest live-doc
+    // state. A concurrent UI edit that is still in-flight (the store is debounced)
+    // must be drained into the live doc BEFORE git merges, or git clean-applies and
+    // the edit is silently dropped — even on a DIFFERENT block. Model the drain via
+    // the pending-store flush: when it runs, the in-flight block-0 edit lands.
+    const shared = new Y.Doc();
+    const frag = shared.getXmlFragment('default');
+    shared.transact(() => {
+      frag.insert(
+        0,
+        [
+          { text: 'alpha', id: 'p1' },
+          { text: 'beta', id: 'p2' },
+        ].map((s) => {
+          const el = new Y.XmlElement('paragraph');
+          el.setAttribute('id', s.id);
+          const t = new Y.XmlText();
+          t.insert(0, s.text);
+          el.insert(0, [t]);
+          return el;
+        }),
+      );
+    });
+
+    const order: string[] = [];
+    const debouncer = {
+      isDebounced: jest.fn(() => true),
+      executeNow: jest.fn(async () => {
+        order.push('flush');
+        // The in-flight client edit to block 0 only lands once the pending store
+        // is flushed (i.e. the event loop is drained) — BEFORE the merge.
+        shared.transact(() =>
+          ((frag.get(0) as Y.XmlElement).get(0) as Y.XmlText).insert(5, ' EDIT'),
+        );
+      }),
+    };
+    const openDirectConnection = jest.fn(async () => ({
+      transact: async (fn: (doc: Y.Doc) => void) => {
+        order.push('merge');
+        fn(shared);
+      },
+      disconnect: jest.fn(async () => undefined),
+    }));
+    const hocuspocus = { openDirectConnection, debouncer } as any;
+
+    const handler = new CollaborationHandler();
+    await handler.getHandlers(hocuspocus).gitSyncWriteBody('page.x', {
+      prosemirrorJson: pmDoc('alpha', 'beta2'), // git changes block 1
+      baseProsemirrorJson: pmDoc('alpha', 'beta'),
+      userId: 'svc-user',
+    });
+
+    // The flush ran, and it ran BEFORE the merge transaction.
+    expect(debouncer.executeNow).toHaveBeenCalledTimes(1);
+    expect(order).toEqual(['flush', 'merge']);
+    // Both the in-flight block-0 edit and git's block-1 change survive — the
+    // pre-flush bug would have produced ['alpha', 'beta2'] (UI edit dropped).
+    expect(texts(shared.getXmlFragment('default'))).toEqual([
+      'alpha EDIT',
+      'beta2',
+    ]);
+  });
+
+  it('does not flush when no store is pending (isDebounced false)', async () => {
+    const { hocuspocus, shared } = fakeHocuspocus([{ text: 'a', id: 'p1' }]);
+    const executeNow = jest.fn();
+    (hocuspocus as any).debouncer = {
+      isDebounced: jest.fn(() => false),
+      executeNow,
+    };
+    const handler = new CollaborationHandler();
+    await handler.getHandlers(hocuspocus).gitSyncWriteBody('page.x', {
+      prosemirrorJson: pmDoc('a', 'b'),
+      userId: 'svc-user',
+    });
+    expect(executeNow).not.toHaveBeenCalled();
+    expect(texts(shared.getXmlFragment('default'))).toEqual(['a', 'b']);
+  });
+
+  it('crash-safe: a transform failure never opens the connection or mutates the live doc', async () => {
+    const { hocuspocus, shared } = fakeHocuspocus([{ text: 'alpha', id: 'p1' }]);
+    const before = texts(shared.getXmlFragment('default'));
+    const handler = new CollaborationHandler();
+
+    await expect(
+      handler.getHandlers(hocuspocus).gitSyncWriteBody('page.x', {
+        prosemirrorJson: { __throw: true } as any,
+        userId: 'svc-user',
+      }),
+    ).rejects.toThrow('boom');
+
+    // The incoming doc is built BEFORE opening the connection, so the throw
+    // happens first: the live doc is untouched and no connection was opened.
+    expect(hocuspocus.openDirectConnection).not.toHaveBeenCalled();
+    expect(texts(shared.getXmlFragment('default'))).toEqual(before);
+  });
+
+  it('falls back to a 2-way merge when no base is supplied', async () => {
+    const { hocuspocus, shared, editor } = fakeHocuspocus([
+      { text: 'alpha', id: 'p1' },
+    ]);
+    const handler = new CollaborationHandler();
+
+    await handler.getHandlers(hocuspocus).gitSyncWriteBody('page.x', {
+      prosemirrorJson: pmDoc('alpha', 'gamma'),
+      userId: 'svc-user',
+    });
+
+    expect(texts(shared.getXmlFragment('default'))).toEqual(['alpha', 'gamma']);
+    expect(texts(editor.getXmlFragment('default'))).toEqual(['alpha', 'gamma']);
+  });
+});

apps/server/src/collaboration/collaboration.handler.ts

@@ -8,6 +8,10 @@ import {
 import { setYjsMark, updateYjsMarkAttribute, YjsSelection } from './yjs.util';
 import * as Y from 'yjs';
 import { User } from '@docmost/db/types/entity.types';
+import {
+  mergeXmlFragments,
+  mergeXmlFragments3WayWithStats,
+} from './merge/yjs-body-merge';
 
 export type CollabEventHandlers = ReturnType<
   CollaborationHandler['getHandlers']
@@ -112,9 +116,130 @@ export class CollaborationHandler {
           },
         );
       },
+      /**
+       * Git-sync body write, applied as a block-level MERGE into the LIVE doc on
+       * the instance that OWNS it (routed here via the custom-event channel —
+       * see CollaborationGateway.writePageBody). Running on the owning instance
+       * is what makes a connected editor CONVERGE: the merge mutates the shared
+       * Document, whose update is broadcast to every connection, so the editor's
+       * CRDT applies the git change instead of silently reverting it on its next
+       * autosave (the data-loss bug this fixes).
+       *
+       * With a `baseProsemirrorJson` (the last-synced common ancestor) it does a
+       * THREE-WAY merge — a block only the human changed is kept, a block only
+       * git changed is taken (conflicts -> git). Without a base it falls back to
+       * the 2-way merge.
+       */
+      gitSyncWriteBody: async (
+        documentName: string,
+        payload: {
+          prosemirrorJson: any;
+          baseProsemirrorJson?: any;
+          userId: string;
+        },
+      ) => {
+        const { prosemirrorJson, baseProsemirrorJson, userId } = payload;
+
+        // Build the incoming (and base) Yjs docs BEFORE opening the connection /
+        // touching the live doc. If a transform throws (a malformed/unsupported
+        // doc) we must NOT have mutated the live body — otherwise a conversion
+        // failure could leave the page empty (crash-safe conversion).
+        const targetDoc = TiptapTransformer.toYdoc(
+          prosemirrorJson,
+          'default',
+          tiptapExtensions,
+        );
+        const baseDoc =
+          baseProsemirrorJson != null
+            ? TiptapTransformer.toYdoc(
+                baseProsemirrorJson,
+                'default',
+                tiptapExtensions,
+              )
+            : null;
+
+        // CONCURRENT-EDIT FLUSH (QA #119, finding #2). The 3-way merge below runs
+        // against the LIVE Y.Doc, so a concurrent UI edit is only preserved if it
+        // is already part of that doc. A user's edit is debounced before it lands
+        // (the editor batches; the collab store is debounced up to 10s), so the
+        // merge could otherwise run against a PRE-EDIT doc: git would then
+        // clean-apply (no same-block conflict detected) and the in-flight UI edit
+        // — even on a DIFFERENT block — would be silently dropped.
+        //
+        // Flushing the pending debounced store here (a) drains the event loop so a
+        // just-arrived client Yjs update is applied to the live doc BEFORE we
+        // merge, and (b) persists the live doc so the merge baseline is current
+        // even on the doc-reload-from-DB path. After the flush the merge sees the
+        // latest state, so an edit on a different block is MERGED (not overwritten)
+        // and a genuine same-block edit is detected as a conflict -> the
+        // boundary-snapshot in PersistenceExtension pins it to page history
+        // (recoverable) instead of vanishing silently.
+        await this.flushPendingStore(hocuspocus, documentName);
+
+        // actor:'git-sync' + the service user flow into PersistenceExtension
+        // (lastUpdatedSource='git-sync', lastUpdatedById=userId).
+        await this.withYdocConnection(
+          hocuspocus,
+          documentName,
+          { actor: 'git-sync', user: { id: userId } },
+          (doc) => {
+            const liveFrag = doc.getXmlFragment('default');
+            const targetFrag = targetDoc.getXmlFragment('default');
+            if (baseDoc) {
+              const { conflicts } = mergeXmlFragments3WayWithStats(
+                liveFrag,
+                targetFrag,
+                baseDoc.getXmlFragment('default'),
+              );
+              // SAME-BLOCK conflict contract (SPEC §9): a block both the human
+              // and git changed resolves to GIT (deterministic). Make that
+              // OBSERVABLE rather than silent — log it. The losing human content
+              // is NOT destroyed: the persistence extension's boundary snapshot
+              // pins the pre-merge page state to history on this user->git-sync
+              // transition, so it stays recoverable.
+              if (conflicts > 0) {
+                this.logger.warn(
+                  `git-sync merge for ${documentName}: ${conflicts} same-block ` +
+                    `conflict(s) resolved to the git version; the prior page ` +
+                    `state is preserved in page history (recoverable).`,
+                );
+              }
+            } else {
+              mergeXmlFragments(liveFrag, targetFrag);
+            }
+          },
+        );
+      },
     };
   }
 
+  /**
+   * Flush any pending DEBOUNCED store for `documentName` so the live Y.Doc and the
+   * DB are current BEFORE a git-sync merge reads them (QA #119, finding #2 —
+   * concurrent UI edit silently lost). Mirrors the PersistenceExtension.onDisconnect
+   * flush: only acts when a store is actually pending (`isDebounced`), runs the
+   * SAME scheduled payload (`executeNow`, preserving the edit's context/actor), and
+   * never throws — a flush failure must not abort the git-sync write. Awaiting it
+   * also drains the event loop, so a client Yjs update sitting in the socket buffer
+   * is applied to the live doc before the merge transaction runs.
+   */
+  private async flushPendingStore(
+    hocuspocus: Hocuspocus,
+    documentName: string,
+  ): Promise<void> {
+    const debounceId = `onStoreDocument-${documentName}`;
+    try {
+      const debouncer = (hocuspocus as any)?.debouncer;
+      if (!debouncer?.isDebounced?.(debounceId)) return;
+      await debouncer.executeNow(debounceId);
+    } catch (err) {
+      this.logger.warn(
+        `git-sync pre-merge flush failed for ${documentName}: ` +
+          (err instanceof Error ? err.message : String(err)),
+      );
+    }
+  }
+
   async withYdocConnection(
     hocuspocus: Hocuspocus,
     documentName: string,

apps/server/src/collaboration/extensions/persistence-store.spec.ts

@@ -205,6 +205,32 @@ describe('PersistenceExtension.onStoreDocument — Approach-A boundary snapshot'
     expect(historyQueue.add).toHaveBeenCalledTimes(1);
   });
 
+  // #206 persist-6 — RED (it.failing): a momentarily-empty live Y.Doc must not
+  // overwrite non-empty persisted content. `onStoreDocument` empty-guards the
+  // LOAD path but not the STORE path, so today an empty doc (a client/agent
+  // glitch, a bad merge, an emptying transclusion) is written straight over the
+  // page and the content is wiped silently. A store-side empty-guard is a real
+  // behaviour change (a deliberate "select-all + delete" is also empty), so it
+  // is left UNFIXED pending a product decision; this documents the data-loss
+  // path and flips to a normal passing test the moment the guard lands.
+  it.failing(
+    'does NOT overwrite non-empty content with a momentarily-empty live doc (persist-6)',
+    async () => {
+      const emptyDoc = { type: 'doc', content: [{ type: 'paragraph' }] };
+      const document = ydocFor(emptyDoc);
+      pageRepo.findById.mockResolvedValue({
+        ...persistedHumanPage('IGNORED'),
+        content: doc('IMPORTANT RICH CONTENT'),
+      });
+
+      await ext.onStoreDocument(buildData(document, 'user') as any);
+
+      // Desired contract: the empty incoming doc is rejected and the rich page
+      // survives. Today updatePage is called with the empty content (data loss).
+      expect(pageRepo.updatePage).not.toHaveBeenCalled();
+    },
+  );
+
   // persist-1 — when every attempt fails the hook must NOT report a phantom
   // success: no "page.updated" badge broadcast and no history snapshot for
   // content that was never written.

apps/server/src/collaboration/extensions/persistence.disconnect-flush.spec.ts

@@ -0,0 +1,89 @@
+import { PersistenceExtension } from './persistence.extension';
+
+/**
+ * Regression for the QA #119 "loss-on-fast-close" data loss: editing a page then
+ * closing the tab within the collab debounce window (~3-18s) lost the edit
+ * because, with `unloadImmediately: false`, Hocuspocus does NOT flush the
+ * debounced onStoreDocument on a last-client disconnect. PersistenceExtension
+ * now flushes the pending store on the LAST disconnect (and only then).
+ */
+describe('PersistenceExtension.onDisconnect flush (loss-on-fast-close)', () => {
+  function makeExt(): PersistenceExtension {
+    // onDisconnect touches none of the injected deps; pass casts.
+    return new PersistenceExtension(
+      null as any,
+      null as any,
+      null as any,
+      null as any,
+      null as any,
+      null as any,
+      null as any,
+      null as any,
+    );
+  }
+
+  function makeData(opts: {
+    clientsCount: number;
+    isDebounced: boolean;
+    isLoading?: boolean;
+  }) {
+    const executeNow = jest.fn(async () => undefined);
+    const isDebounced = jest.fn(() => opts.isDebounced);
+    return {
+      executeNow,
+      isDebounced,
+      payload: {
+        clientsCount: opts.clientsCount,
+        context: {},
+        document: { isLoading: opts.isLoading ?? false } as any,
+        documentName: 'page.abc',
+        instance: { debouncer: { isDebounced, executeNow } } as any,
+        requestHeaders: {},
+        requestParameters: new URLSearchParams(),
+        socketId: 's',
+      } as any,
+    };
+  }
+
+  it('flushes the pending store when the LAST client disconnects', async () => {
+    const ext = makeExt();
+    const { executeNow, payload } = makeData({
+      clientsCount: 0,
+      isDebounced: true,
+    });
+    await ext.onDisconnect(payload);
+    expect(executeNow).toHaveBeenCalledTimes(1);
+    expect(executeNow).toHaveBeenCalledWith('onStoreDocument-page.abc');
+  });
+
+  it('does NOT flush while other editors remain connected', async () => {
+    const ext = makeExt();
+    const { executeNow, payload } = makeData({
+      clientsCount: 2,
+      isDebounced: true,
+    });
+    await ext.onDisconnect(payload);
+    expect(executeNow).not.toHaveBeenCalled();
+  });
+
+  it('does NOT write when nothing is pending (already persisted)', async () => {
+    const ext = makeExt();
+    const { executeNow, payload } = makeData({
+      clientsCount: 0,
+      isDebounced: false,
+    });
+    await ext.onDisconnect(payload);
+    expect(executeNow).not.toHaveBeenCalled();
+  });
+
+  it('does NOT flush a doc that is still loading (load error guard)', async () => {
+    const ext = makeExt();
+    const { executeNow, payload } = makeData({
+      clientsCount: 0,
+      isDebounced: true,
+      isLoading: true,
+    });
+    await ext.onDisconnect(payload);
+    expect(executeNow).not.toHaveBeenCalled();
+  });
+});

apps/server/src/collaboration/extensions/persistence.extension.spec.ts

@@ -0,0 +1,223 @@
+// Stub collaboration.util so importing the extension does not drag in the
+// editor-ext -> @tiptap/react -> react-dom graph (unloadable under jest's node
+// env, same coupling the gitmost-datasource / mcp specs document). The
+// extension only calls getPageId, jsonToText and isEmptyParagraphDoc from it on
+// the store path; tiptapExtensions is unused by onStoreDocument.
+jest.mock('../collaboration.util', () => ({
+  tiptapExtensions: [],
+  getPageId: (name: string) => name.replace(/^page\./, ''),
+  jsonToText: () => 'text',
+  isEmptyParagraphDoc: () => false,
+  // The post-write mention extraction walks the doc via jsonToNode().descendants;
+  // return a node-like stub with no descendants so no mentions are produced
+  // (mention handling is out of scope here — we only assert provenance).
+  jsonToNode: () => ({ descendants: () => undefined }),
+}));
+
+// Control the Yjs<->JSON bridge: fromYdoc returns the "incoming" doc the writer
+// is storing. We keep it distinct from the page's persisted content so the
+// no-op guard (isDeepStrictEqual) never short-circuits the write.
+const INCOMING_JSON = { type: 'doc', content: [{ type: 'paragraph' }, { t: 1 }] };
+jest.mock('@hocuspocus/transformer', () => ({
+  TiptapTransformer: {
+    fromYdoc: jest.fn(() => INCOMING_JSON),
+    toYdoc: jest.fn(),
+  },
+}));
+
+// Run the executeTx callback inline with a passthrough trx.
+jest.mock('@docmost/db/utils', () => ({
+  executeTx: jest.fn(async (_db: any, cb: any) => cb({} as any)),
+}));
+
+import * as Y from 'yjs';
+import { PersistenceExtension } from './persistence.extension';
+import {
+  onChangePayload,
+  onStoreDocumentPayload,
+} from '@hocuspocus/server';
+
+/**
+ * Provenance-precedence coverage for PersistenceExtension.onStoreDocument
+ * (test-strategy Module 4 / item #2): the contract `agent > git-sync > user`,
+ * plus the negative that a git-sync store does NOT pin a boundary history
+ * snapshot. We drive the precedence through the real public method (onChange to
+ * arm the sticky agent marker, then onStoreDocument), mocking the repos / db /
+ * Yjs bridge so no real database or collab server is needed. The store's
+ * persisted `lastUpdatedSource` and the saveHistory call are the observable
+ * outputs.
+ */
+describe('PersistenceExtension.onStoreDocument — provenance precedence (#2)', () => {
+  const DOCUMENT_NAME = 'page.page-1';
+  const PAGE_ID = 'page-1';
+
+  // `page.content` differs from INCOMING_JSON so the write is never skipped.
+  const persistedPage = (overrides?: { lastUpdatedSource?: string }) => ({
+    id: PAGE_ID,
+    slugId: 'slug-1',
+    spaceId: 'space-1',
+    workspaceId: 'ws-1',
+    creatorId: 'creator-1',
+    contributorIds: ['creator-1'],
+    content: { type: 'doc', content: [{ type: 'paragraph', content: [] }] },
+    lastUpdatedSource: overrides?.lastUpdatedSource ?? 'user',
+    createdAt: new Date(),
+  });
+
+  const build = (pageOverrides?: { lastUpdatedSource?: string }) => {
+    const pageRepo = {
+      findById: jest.fn().mockResolvedValue(persistedPage(pageOverrides)),
+      updatePage: jest.fn().mockResolvedValue({ numUpdatedRows: 1n }),
+    };
+    const pageHistoryRepo = {
+      // No prior snapshot -> humanBaselineMissing is true, so the ONLY thing
+      // gating the boundary snapshot in these tests is the source precedence.
+      findPageLastHistory: jest.fn().mockResolvedValue(null),
+      saveHistory: jest.fn().mockResolvedValue(undefined),
+    };
+    const aiQueue = { add: jest.fn().mockResolvedValue(undefined) };
+    const historyQueue = { add: jest.fn().mockResolvedValue(undefined) };
+    const notificationQueue = { add: jest.fn().mockResolvedValue(undefined) };
+    const collabHistory = {
+      addContributors: jest.fn().mockResolvedValue(undefined),
+    };
+    const transclusionService = {
+      syncPageTransclusions: jest.fn().mockResolvedValue(undefined),
+      syncPageReferences: jest.fn().mockResolvedValue(undefined),
+      syncPageTemplateReferences: jest.fn().mockResolvedValue(undefined),
+    };
+
+    const ext = new PersistenceExtension(
+      pageRepo as any,
+      pageHistoryRepo as any,
+      {} as any, // db
+      aiQueue as any,
+      historyQueue as any,
+      notificationQueue as any,
+      collabHistory as any,
+      transclusionService as any,
+    );
+
+    return { ext, pageRepo, pageHistoryRepo, historyQueue };
+  };
+
+  // A real Y.Doc is required for Y.encodeStateAsUpdate(document); broadcastStateless
+  // is a no-op spy. The fromYdoc bridge is mocked, so the doc's contents are
+  // irrelevant to the JSON path.
+  const makeStorePayload = (context: any): onStoreDocumentPayload =>
+    ({
+      documentName: DOCUMENT_NAME,
+      document: Object.assign(new Y.Doc(), {
+        broadcastStateless: jest.fn(),
+      }),
+      context,
+    }) as any;
+
+  const makeChangePayload = (actor: string): onChangePayload =>
+    ({
+      documentName: DOCUMENT_NAME,
+      context: { user: { id: 'user-1' }, actor },
+    }) as any;
+
+  const sourceOf = (pageRepo: { updatePage: jest.Mock }) =>
+    pageRepo.updatePage.mock.calls[0][0].lastUpdatedSource;
+
+  it("tags 'user' for a plain write (no agent touch, no git-sync actor)", async () => {
+    const { ext, pageRepo } = build();
+
+    await ext.onStoreDocument(
+      makeStorePayload({ user: { id: 'user-1' }, actor: 'user' }),
+    );
+
+    expect(sourceOf(pageRepo)).toBe('user');
+  });
+
+  it("tags 'git-sync' when the writer's actor is 'git-sync' and no agent touched the window", async () => {
+    const { ext, pageRepo } = build();
+
+    await ext.onStoreDocument(
+      makeStorePayload({ user: { id: 'svc-user' }, actor: 'git-sync' }),
+    );
+
+    expect(sourceOf(pageRepo)).toBe('git-sync');
+  });
+
+  it("keeps 'git-sync' for an explicit git-sync store even with a sticky agent marker (#14 loop-guard)", async () => {
+    const { ext, pageRepo } = build();
+
+    // An agent edit landed earlier in the coalescing window (sticky marker),
+    // then a git-sync writer performs the store. Red-team finding #14: an
+    // EXPLICIT current-write actor is authoritative for THIS write, so the
+    // store must stay 'git-sync' — otherwise the PageChangeListener loop-guard
+    // (keyed on lastUpdatedSource === 'git-sync') fails to recognize git-sync's
+    // own write and re-exports it. Explicit 'agent' still wins (see below); the
+    // sticky marker only promotes a plain human writer to 'agent'.
+    await ext.onChange(makeChangePayload('agent'));
+    await ext.onStoreDocument(
+      makeStorePayload({ user: { id: 'svc-user' }, actor: 'git-sync' }),
+    );
+
+    expect(sourceOf(pageRepo)).toBe('git-sync');
+  });
+
+  it("tags 'agent' when the storing writer itself is the agent (no prior onChange)", async () => {
+    const { ext, pageRepo } = build();
+
+    await ext.onStoreDocument(
+      makeStorePayload({ user: { id: 'agent-user' }, actor: 'agent' }),
+    );
+
+    expect(sourceOf(pageRepo)).toBe('agent');
+  });
+
+  // --- boundary snapshot for a git-sync store over a HUMAN baseline -----------
+  // SPEC §9 observable-loss guard (bug #2): a git-sync body write is a block-level
+  // 3-way merge whose same-block rule is "git wins". To keep a concurrent human
+  // edit RECOVERABLE rather than silently overwritten, a git-sync store over a
+  // prior NON-git-sync baseline pins that prior state to page history first —
+  // exactly like the agent path. So saveHistory MUST be called here.
+  it('DOES pin a boundary snapshot for a git-sync store over a prior human state', async () => {
+    const { ext, pageHistoryRepo } = build({ lastUpdatedSource: 'user' });
+
+    await ext.onStoreDocument(
+      makeStorePayload({ user: { id: 'svc-user' }, actor: 'git-sync' }),
+    );
+
+    expect(pageHistoryRepo.saveHistory).toHaveBeenCalledTimes(1);
+  });
+
+  // --- negative: a git-sync store over a git-sync baseline does NOT re-pin -----
+  // The boundary is pinned once on the transition INTO git-sync; a subsequent
+  // git-sync store over an already-git-sync baseline must not churn history.
+  it('does NOT re-pin a boundary snapshot for a git-sync store over a git-sync baseline', async () => {
+    const { ext, pageHistoryRepo } = build({ lastUpdatedSource: 'git-sync' });
+
+    await ext.onStoreDocument(
+      makeStorePayload({ user: { id: 'svc-user' }, actor: 'git-sync' }),
+    );
+
+    expect(pageHistoryRepo.saveHistory).not.toHaveBeenCalled();
+  });
+
+  it('DOES pin a boundary snapshot for an agent store over a prior human state (control)', async () => {
+    // Confirms the negative above is meaningful: under the SAME mocks, an agent
+    // store over a 'user' baseline DOES trigger the boundary snapshot.
+    const { ext, pageHistoryRepo } = build({ lastUpdatedSource: 'user' });
+
+    await ext.onStoreDocument(
+      makeStorePayload({ user: { id: 'agent-user' }, actor: 'agent' }),
+    );
+
+    expect(pageHistoryRepo.saveHistory).toHaveBeenCalledTimes(1);
+  });
+
+  it('does NOT pin a boundary snapshot for a plain user store', async () => {
+    const { ext, pageHistoryRepo } = build({ lastUpdatedSource: 'user' });
+
+    await ext.onStoreDocument(
+      makeStorePayload({ user: { id: 'user-1' }, actor: 'user' }),
+    );
+
+    expect(pageHistoryRepo.saveHistory).not.toHaveBeenCalled();
+  });
+});

apps/server/src/collaboration/extensions/persistence.extension.ts

@@ -2,6 +2,7 @@ import {
   afterUnloadDocumentPayload,
   Extension,
   onChangePayload,
+  onDisconnectPayload,
   onLoadDocumentPayload,
   onStoreDocumentPayload,
 } from '@hocuspocus/server';
@@ -52,7 +53,17 @@ export function resolveSource(
   stickyTouched: boolean,
   contextActor?: string,
 ): ProvenanceSource {
-  return stickyTouched || contextActor === 'agent' ? 'agent' : 'user';
+  // An EXPLICIT current-write actor is authoritative for THIS write and wins
+  // over the sticky-agent fallback. Order: explicit 'agent' > explicit
+  // 'git-sync' > sticky agent marker > plain human 'user'. The git-sync case
+  // must NOT be masked by the sticky marker, or the PageChangeListener
+  // loop-guard (which keys on lastUpdatedSource === 'git-sync') would re-export
+  // git-sync's own writes (#14). Explicit agent still wins so a window that
+  // mixed an agent edit stays tagged 'agent'.
+  if (contextActor === 'agent') return 'agent';
+  if (contextActor === 'git-sync') return 'git-sync';
+  if (stickyTouched) return 'agent';
+  return 'user';
 }
 
 /**
@@ -154,6 +165,40 @@ export class PersistenceExtension implements Extension {
     return new Y.Doc();
   }
 
+  /**
+   * LOSS-ON-FAST-CLOSE FIX (QA #119). When the LAST editor disconnects, FLUSH any
+   * pending (debounced) store to the DB IMMEDIATELY instead of waiting out the
+   * up-to-10s `debounce` window.
+   *
+   * The collab server runs with `unloadImmediately: false` (collaboration.gateway),
+   * so on a last-client disconnect Hocuspocus does NOT flush the debounced
+   * onStoreDocument — it relies on the timer firing later. A quick edit-then-close
+   * (closing the tab within the debounce window, ~3-18s) therefore left the edit
+   * only in the soon-to-be-unloaded in-memory Y.Doc; meanwhile git-sync mirrored
+   * the STALE/empty DB body to the vault (the reported "59-byte frontmatter-only"
+   * data loss). Running the already-scheduled store now closes that window.
+   *
+   * Gated tightly so it never adds a redundant write: only on the LAST disconnect
+   * (`clientsCount === 0`), only for a fully-loaded doc, and only when a store is
+   * actually pending (`isDebounced`). `executeNow` runs the SAME payload Hocuspocus
+   * scheduled (preserving the edit's context/actor) and clears the timer.
+   */
+  async onDisconnect(data: onDisconnectPayload) {
+    const { instance, document, documentName, clientsCount } = data;
+    if (clientsCount > 0) return;
+    if (!document || document.isLoading) return;
+    const debounceId = `onStoreDocument-${documentName}`;
+    if (!instance?.debouncer?.isDebounced(debounceId)) return;
+    try {
+      await instance.debouncer.executeNow(debounceId);
+    } catch (err) {
+      this.logger.error(
+        `onDisconnect flush failed for ${documentName}: ` +
+          (err instanceof Error ? err.message : String(err)),
+      );
+    }
+  }
+
   async onStoreDocument(data: onStoreDocumentPayload) {
     const { documentName, document, context } = data;
 
@@ -176,6 +221,11 @@ export class PersistenceExtension implements Extension {
     // Sticky agent marker: 'agent' if any agent edit landed in this window, OR
     // if the current writer is the agent (covers a store with no prior onChange
     // agent event in the same window). §15 H2.
+    // Provenance precedence: agent > git-sync > user (see resolveSource). A
+    // 'git-sync' store is NOT given an immediate history snapshot — it is
+    // debounced like a human edit (a git-sync write is a block-level merge into
+    // the live doc, so it reads like an incremental human edit, not a bulk
+    // import that would warrant its own immediate snapshot).
     const lastUpdatedSource = resolveSource(
       this.consumeAgentTouched(documentName),
       context?.actor,
@@ -224,21 +274,30 @@ export class PersistenceExtension implements Extension {
             //this.logger.debug('Contributors error:' + err?.['message']);
           }
 
-          // Approach A — boundary snapshot before the agent's first edit.
-          // When this store is the agent's and the page's currently persisted
-          // state was authored by a human, pin that human state as its own
-          // history version BEFORE the agent overwrites it. `page` still holds
-          // the OLD content/provenance here, so saveHistory(page) captures the
-          // pre-agent state tagged 'user'. The agent's new content is
-          // snapshotted later by the debounced PAGE_HISTORY job ('agent'). Skip
-          // if the prior state is already agent-authored (boundary already
-          // pinned on the user->agent transition), if the page is effectively
-          // empty, or if the latest existing snapshot already equals this human
-          // state (avoid duplicates).
-          if (
-            lastUpdatedSource === 'agent' &&
-            page.lastUpdatedSource !== 'agent'
-          ) {
+          // Approach A — boundary snapshot before a MACHINE write overwrites a
+          // human (or other-source) baseline. When this store is from a machine
+          // source — the AGENT or GIT-SYNC — and the page's currently persisted
+          // state was authored by a DIFFERENT source, pin that prior state as its
+          // own history version BEFORE the machine write overwrites it. `page`
+          // still holds the OLD content/provenance here, so saveHistory(page)
+          // captures the pre-write state. The machine's new content is snapshotted
+          // later by the debounced PAGE_HISTORY job.
+          //
+          // For GIT-SYNC this is the OBSERVABLE-LOSS guard (SPEC §9 conflict
+          // contract): a git-sync body write is a block-level 3-way merge whose
+          // same-block rule is "git wins". Without this pin, a concurrent human
+          // edit to a block git also changed would be overwritten with NO trace.
+          // Pinning the pre-merge state here means the human's content is always
+          // RECOVERABLE via page history rather than silently lost — git still
+          // wins the live doc deterministically, but nothing is destroyed.
+          //
+          // Skip if the prior state was already authored by THIS machine source
+          // (boundary already pinned on the transition into it), if the page is
+          // effectively empty, or if the latest existing snapshot already equals
+          // the prior state (avoid duplicates).
+          const isMachineWrite =
+            lastUpdatedSource === 'agent' || lastUpdatedSource === 'git-sync';
+          if (isMachineWrite && page.lastUpdatedSource !== lastUpdatedSource) {
             const lastHistory = await this.pageHistoryRepo.findPageLastHistory(
               pageId,
               { includeContent: true, trx },

apps/server/src/collaboration/extensions/redis-sync/redis-sync.extension.spec.ts

@@ -0,0 +1,208 @@
+// Regression coverage for the custom-event request/reply protocol in the
+// RedisSyncExtension. git-sync routes its body write through a custom event
+// (`gitSyncWriteBody`) which, when the target doc is owned by a DIFFERENT collab
+// instance, runs REMOTELY inside `handleRedisMessage` on the owning instance. The
+// remote handler can THROW (markdown->ProseMirror transform on a malformed body).
+//
+// Before the fix the throw was uncaught: (1) no `customEventComplete` reply was
+// published, so the origin's awaiting promise only rejected after `customEventTTL`
+// (~30s) as a generic 'TIMEOUT', and (2) an unhandledRejection escaped the async
+// `messageBuffer` listener on the owning instance. These tests assert the throw is
+// turned into an error-carrying reply that rejects the origin PROMPTLY with the
+// real message, with the no-throw and local paths unchanged.
+
+import { RedisSyncExtension } from './redis-sync.extension';
+
+type Listener = (channel: Buffer, message: Buffer) => unknown;
+
+// Minimal in-memory pub/sub + lock store shared across FakeRedis duplicates,
+// modelling the two-instance topology (origin + owner) over one Redis.
+class FakeRedisBus {
+  instances: FakeRedis[] = [];
+  locks = new Map<string, string>();
+  published: { channel: string; message: Buffer }[] = [];
+
+  register(inst: FakeRedis) {
+    this.instances.push(inst);
+  }
+
+  publish(channel: string, message: Buffer) {
+    this.published.push({ channel, message });
+    for (const inst of this.instances) {
+      if (!inst.subscribed.has(channel)) continue;
+      for (const listener of inst.messageListeners) {
+        // ioredis delivers async; `void` mirrors the production listener
+        // registration (`sub.on('messageBuffer', ...)`), whose rejection would
+        // surface as an unhandledRejection if the handler did not catch.
+        void listener(Buffer.from(channel), message);
+      }
+    }
+  }
+}
+
+class FakeRedis {
+  subscribed = new Set<string>();
+  messageListeners: Listener[] = [];
+
+  constructor(private bus: FakeRedisBus) {
+    bus.register(this);
+  }
+
+  duplicate() {
+    return new FakeRedis(this.bus);
+  }
+
+  subscribe(...channels: string[]) {
+    for (const c of channels) this.subscribed.add(c);
+    return Promise.resolve();
+  }
+
+  on(event: string, cb: any) {
+    if (event === 'messageBuffer') this.messageListeners.push(cb as Listener);
+    return this;
+  }
+
+  publish(channel: string, message: Buffer) {
+    this.bus.publish(channel, message);
+    return Promise.resolve(1);
+  }
+
+  // Models `SET key val PX ttl NX GET`: only writes when absent (NX); returns the
+  // previous value (GET) so the origin observes the owner already holding the lock.
+  set(key: string, val: string, ...args: any[]) {
+    const hasNX = args.includes('NX');
+    const hasGET = args.includes('GET');
+    const old = this.bus.locks.get(key) ?? null;
+    if (!hasNX || old === null) this.bus.locks.set(key, val);
+    return Promise.resolve(hasGET ? old : 'OK');
+  }
+
+  del(key: string) {
+    this.bus.locks.delete(key);
+    return Promise.resolve(1);
+  }
+
+  disconnect() {}
+}
+
+const pack = (m: any) => Buffer.from(JSON.stringify(m));
+const unpack = (b: Buffer) => JSON.parse(b.toString());
+
+function makeExtension(
+  bus: FakeRedisBus,
+  serverId: string,
+  customEvents: Record<string, (doc: string, payload: any) => Promise<any>>,
+) {
+  const ext = new RedisSyncExtension({
+    redis: new FakeRedis(bus) as any,
+    pack: pack as any,
+    unpack: unpack as any,
+    serverId,
+    customEvents: customEvents as any,
+    customEventTTL: 30_000,
+  });
+  // Doc is NOT loaded on this instance -> handleEvent takes the remote/proxy path.
+  (ext as any).instance = { documents: new Map() };
+  return ext;
+}
+
+describe('RedisSyncExtension custom-event error propagation', () => {
+  let unhandled: unknown[];
+  let onUnhandled: (e: unknown) => void;
+
+  beforeEach(() => {
+    // Fake timers so the 30s TTL fallback timer never fires (and never dangles).
+    jest.useFakeTimers();
+    unhandled = [];
+    onUnhandled = (e) => unhandled.push(e);
+    process.on('unhandledRejection', onUnhandled);
+  });
+
+  afterEach(() => {
+    process.off('unhandledRejection', onUnhandled);
+    jest.useRealTimers();
+  });
+
+  const flush = async () => {
+    for (let i = 0; i < 10; i++) await Promise.resolve();
+  };
+
+  it('owner publishes an error-carrying reply (no unhandledRejection) when the remote handler throws', async () => {
+    const bus = new FakeRedisBus();
+    const owner = makeExtension(bus, 'owner', {
+      boom: async () => {
+        throw new Error('kaboom');
+      },
+    });
+
+    // Drive the remote branch directly, as if the origin's customEventStart arrived.
+    await (owner as any).handleRedisMessage(
+      Buffer.from('collabMsg:owner'),
+      pack({
+        type: 'customEventStart',
+        documentName: 'page.x',
+        eventName: 'boom',
+        payload: {},
+        replyTo: 'collabMsg:origin',
+        replyId: 7,
+      }),
+    );
+    await flush();
+
+    const replies = bus.published
+      .filter((p) => p.channel === 'collabMsg:origin')
+      .map((p) => unpack(p.message));
+    expect(replies).toHaveLength(1);
+    expect(replies[0]).toMatchObject({
+      type: 'customEventComplete',
+      replyId: 7,
+      error: 'kaboom',
+    });
+    expect(unhandled).toHaveLength(0);
+  });
+
+  it('origin rejects PROMPTLY with the real error (not a TTL TIMEOUT) when the remote handler throws', async () => {
+    const bus = new FakeRedisBus();
+    // Owner already holds the document lock.
+    bus.locks.set('collabLock:page.x', 'owner');
+    makeExtension(bus, 'owner', {
+      boom: async () => {
+        throw new Error('kaboom');
+      },
+    });
+    const origin = makeExtension(bus, 'origin', {
+      boom: async () => undefined,
+    });
+
+    const promise = (origin as any).handleEvent('boom', 'page.x', { foo: 1 });
+    // Attach a catch immediately so a rejection is never momentarily unhandled.
+    const settled = promise.then(
+      () => ({ ok: true as const }),
+      (e: unknown) => ({ ok: false as const, error: e }),
+    );
+
+    await flush();
+    // Resolves WITHOUT advancing any timer -> the 30s TIMEOUT fallback did not fire.
+    const result = await settled;
+    expect(result.ok).toBe(false);
+    expect((result as any).error).toBeInstanceOf(Error);
+    expect(((result as any).error as Error).message).toBe('kaboom');
+    expect(unhandled).toHaveLength(0);
+  });
+
+  it('origin resolves with the payload when the remote handler succeeds (unchanged behavior)', async () => {
+    const bus = new FakeRedisBus();
+    bus.locks.set('collabLock:page.x', 'owner');
+    makeExtension(bus, 'owner', {
+      ok: async (_doc: string, payload: any) => ({ echoed: payload }),
+    });
+    const origin = makeExtension(bus, 'origin', {
+      ok: async () => undefined,
+    });
+
+    const promise = (origin as any).handleEvent('ok', 'page.x', { foo: 1 });
+    await flush();
+    await expect(promise).resolves.toEqual({ echoed: { foo: 1 } });
+    expect(unhandled).toHaveLength(0);
+  });
+});

apps/server/src/collaboration/extensions/redis-sync/redis-sync.extension.ts

@@ -51,9 +51,15 @@ export class RedisSyncExtension<TCE extends CustomEvents> implements Extension {
   private instance!: Hocuspocus;
   private readonly customEvents: TCE;
   private replyIdCounter: number = 0;
-  // @ts-ignore
-  private pendingReplies: Record<number, PromiseWithResolvers<any>['resolve']> =
-    {};
+  private pendingReplies: Record<
+    number,
+    {
+      // @ts-ignore
+      resolve: PromiseWithResolvers<any>['resolve'];
+      // @ts-ignore
+      reject: PromiseWithResolvers<any>['reject'];
+    }
+  > = {};
 
   constructor(configuration: Configuration<TCE>) {
     const {
@@ -176,25 +182,45 @@ export class RedisSyncExtension<TCE extends CustomEvents> implements Extension {
     }
     if (type === 'customEventStart') {
       const { documentName, eventName, payload, replyTo, replyId } = msg;
-      const res = await this.handleEventLocally(
-        eventName as Extract<keyof TCE, string>,
-        documentName,
-        payload,
-      );
-      const reply: RSAMessageCustomEventComplete = {
-        type: 'customEventComplete',
-        replyId,
-        payload: res,
-      };
+      let reply: RSAMessageCustomEventComplete;
+      try {
+        const res = await this.handleEventLocally(
+          eventName as Extract<keyof TCE, string>,
+          documentName,
+          payload,
+        );
+        reply = {
+          type: 'customEventComplete',
+          replyId,
+          payload: res,
+        };
+      } catch (err) {
+        // The remote handler threw (e.g. the markdown->ProseMirror transform in
+        // gitSyncWriteBody can throw on a malformed body). Reply with the error on
+        // the SAME correlation channel so the origin rejects promptly with the real
+        // message instead of waiting out customEventTTL as a generic 'TIMEOUT'.
+        // Catching here also keeps the throw from escaping this async messageBuffer
+        // listener as an unhandledRejection on the owning instance.
+        reply = {
+          type: 'customEventComplete',
+          replyId,
+          payload: undefined,
+          error: err instanceof Error ? err.message : String(err),
+        };
+      }
       this.pub.publish(`${replyTo}`, this.pack(reply));
       return;
     }
     if (type === 'customEventComplete') {
-      const { replyId, payload } = msg;
-      const resolveFn = this.pendingReplies[replyId];
-      if (!resolveFn) return;
+      const { replyId, payload, error } = msg;
+      const pending = this.pendingReplies[replyId];
+      if (!pending) return;
       delete this.pendingReplies[replyId];
-      resolveFn(payload);
+      if (error !== undefined) {
+        pending.reject(new Error(error));
+      } else {
+        pending.resolve(payload);
+      }
       return;
     }
     const { socketId } = msg;
@@ -273,11 +299,22 @@ export class RedisSyncExtension<TCE extends CustomEvents> implements Extension {
       };
       const msg = this.pack(proxyMessage);
       this.pub.publish(`${this.msgChannel}:${proxyTo}`, msg);
-      // @ts-ignore
-      const { promise, resolve, reject } = Promise.withResolvers();
-      this.pendingReplies[replyId] = resolve;
+      // Manual deferred (no Promise.withResolvers) so this runs on Node < 22 too.
+      let resolve!: (v: unknown) => void;
+      let reject!: (e: unknown) => void;
+      const promise = new Promise((res, rej) => {
+        resolve = res;
+        reject = rej;
+      });
+      this.pendingReplies[replyId] = { resolve, reject };
       setTimeout(() => {
-        reject('TIMEOUT');
+        // Fallback for a genuinely lost reply. A handler that threw now rejects
+        // promptly via the error-carrying customEventComplete above; this TIMEOUT
+        // only fires when no reply ever comes back.
+        if (this.pendingReplies[replyId]) {
+          delete this.pendingReplies[replyId];
+          reject('TIMEOUT');
+        }
       }, this.customEventTTL);
       return promise as Promise<ReturnType<TCE[TName]>>;
     }

apps/server/src/collaboration/extensions/redis-sync/redis-sync.types.ts

@@ -72,6 +72,10 @@ export type RSAMessageCustomEventComplete = {
   type: 'customEventComplete';
   replyId: number;
   payload: unknown;
+  // When the remote handler THREW, the owner sends back the error message here
+  // instead of a payload, so the origin can reject its awaiting promise promptly
+  // (with the real error) rather than waiting out the customEventTTL timeout.
+  error?: string;
 };
 
 export type RSAMessage =

apps/server/src/collaboration/git-sync-converter-gate.spec.ts

@@ -0,0 +1,535 @@
+/**
+ * JEST CONFIG NOTE (#119 ESM refactor): this is the one spec that needs the REAL
+ * `@docmost/git-sync` converter (not a mock). The package is now ESM, which jest
+ * cannot `require()` nor `import()` without --experimental-vm-modules, so the
+ * server jest config `moduleNameMapper`s `@docmost/git-sync` to its TS SOURCE and
+ * strips the ESM `.js` import suffixes. ts-jest then type-checks that source under
+ * the server's (looser) tsconfig and trips a benign narrowing; the global
+ * `isolatedModules: true` on the ts-jest transform (apps/server/package.json)
+ * makes it transpile-only so this spec loads. Full type-checking of the package
+ * is still enforced by its own `tsc`/vitest gates and the server `tsc --noEmit`.
+ *
+ * §13.1 IDEMPOTENCY GATE — the blocking gate for git-sync Phase B.
+ *
+ * Proves the `@docmost/git-sync` pure converter is schema-compatible
+ * with the server's REAL editor-ext document schema: a representative corpus of
+ * editor-ext ProseMirror documents must survive a full round trip through the
+ * actual server write path without losing any node / mark / attribute.
+ *
+ * Pipeline per document (issue #194 §13.1):
+ *   1. md   = convertProseMirrorToMarkdown(content)          // git-sync export
+ *   2. doc  = await markdownToProseMirror(md)                // git-sync import
+ *   3. push `doc` through the REAL editor-ext Yjs write path the server uses:
+ *        ydoc       = TiptapTransformer.toYdoc(doc, 'default', tiptapExtensions)
+ *        normalized = TiptapTransformer.fromYdoc(ydoc, 'default')
+ *      This is exactly what PersistenceExtension does on store
+ *      (apps/server/src/collaboration/extensions/persistence.extension.ts:96/115)
+ *      with the same `tiptapExtensions` (collaboration.util.ts) and the same
+ *      `@hocuspocus/transformer`, so the gate exercises the real schema
+ *      validation that runs on a git-sync write (issue #194 §3.3).
+ *   4. assert docsCanonicallyEqual(canon(original), canon(normalized)) === true
+ *
+ * Any node / mark / attr that editor-ext drops (because the git-sync
+ * docmost-schema named it differently, or declares a different default) makes
+ * the gate FAIL for that document — exactly the schema-divergence issue #194 §3.3 /
+ * §13.1 warn about. Genuine, irreducible divergences are isolated into the
+ * clearly-named `KNOWN DIVERGENCE` block at the bottom (never silently hidden).
+ *
+ * Requires the workspace packages built first:
+ *   pnpm --filter @docmost/editor-ext build
+ *   pnpm --filter @docmost/git-sync  build
+ */
+import { TiptapTransformer } from '@hocuspocus/transformer';
+// Import the server's real schema FIRST so `@docmost/editor-ext` resolves to its
+// built CJS `dist` (its `main`). The ESM-only `@docmost/git-sync` package is
+// mapped to its TS SOURCE by the jest `moduleNameMapper` (the built ESM cannot
+// be `require()`d nor dynamically `import()`ed under jest's node VM), so ts-jest
+// transpiles the real converter to CJS here — exercising the actual converter
+// the server ships, not a stub.
+import { tiptapExtensions } from './collaboration.util';
+import {
+  convertProseMirrorToMarkdown,
+  markdownToProseMirror,
+  canonicalizeContent,
+  docsCanonicallyEqual,
+} from '@docmost/git-sync';
+
+/**
+ * Run a single editor-ext document through the full gate pipeline and return
+ * the canonical original vs the canonical doc as it lands after the real Yjs
+ * write path, plus the intermediate markdown for diagnostics.
+ */
+async function runGate(original: any): Promise<{
+  md: string;
+  imported: any;
+  normalized: any;
+  canonOriginal: any;
+  canonNormalized: any;
+}> {
+  // 1) editor-ext JSON -> markdown (git-sync export).
+  const md = convertProseMirrorToMarkdown(original);
+
+  // 2) markdown -> ProseMirror JSON (git-sync import, docmost-schema).
+  const imported = await markdownToProseMirror(md);
+
+  // 3) push through the REAL editor-ext schema via the server's Yjs write path.
+  //    toYdoc validates `imported` against tiptapExtensions (throws on an
+  //    unknown node, drops unknown attrs); fromYdoc reads it back as the
+  //    normalized editor-ext JSON the server would persist.
+  const ydoc = TiptapTransformer.toYdoc(imported, 'default', tiptapExtensions);
+  const normalized = TiptapTransformer.fromYdoc(ydoc, 'default');
+
+  return {
+    md,
+    imported,
+    normalized,
+    canonOriginal: canonicalizeContent(original),
+    canonNormalized: canonicalizeContent(normalized),
+  };
+}
+
+const doc = (...content: any[]) => ({ type: 'doc', content });
+const text = (t: string, marks?: any[]) =>
+  marks ? { type: 'text', text: t, marks } : { type: 'text', text: t };
+const para = (...content: any[]) => ({ type: 'paragraph', content });
+
+// ---------------------------------------------------------------------------
+// Corpus: editor-ext ProseMirror documents covering the common node/mark types.
+// Node / mark / attr names and DEFAULTS are taken from the real schema —
+// editor-ext (packages/editor-ext/src) + the server's tiptapExtensions
+// (collaboration.util.ts) — NOT guessed. Where editor-ext materializes a
+// non-null default on import (e.g. image.align="center", callout.type, list
+// start) the fixture pre-authors that materialized value so the round trip is
+// already at its fixpoint (matches how the engine normalizes-on-write, SPEC §11).
+// ---------------------------------------------------------------------------
+const CORPUS: Record<string, any> = {
+  'paragraphs + headings (h1-h3)': doc(
+    { type: 'heading', attrs: { level: 1 }, content: [text('Heading one')] },
+    { type: 'heading', attrs: { level: 2 }, content: [text('Heading two')] },
+    { type: 'heading', attrs: { level: 3 }, content: [text('Heading three')] },
+    para(text('A plain paragraph of text.')),
+    para(text('Second paragraph.')),
+  ),
+
+  'inline marks (bold/italic/strike/code)': doc(
+    para(
+      text('normal '),
+      text('bold', [{ type: 'bold' }]),
+      text(' '),
+      text('italic', [{ type: 'italic' }]),
+      text(' '),
+      text('struck', [{ type: 'strike' }]),
+      text(' '),
+      text('code', [{ type: 'code' }]),
+    ),
+  ),
+
+  'links': doc(
+    para(
+      text('see '),
+      text('the site', [
+        { type: 'link', attrs: { href: 'https://example.com' } },
+      ]),
+      text(' for more'),
+    ),
+  ),
+
+  'bullet list': doc({
+    type: 'bulletList',
+    content: [
+      { type: 'listItem', content: [para(text('first'))] },
+      { type: 'listItem', content: [para(text('second'))] },
+      { type: 'listItem', content: [para(text('third'))] },
+    ],
+  }),
+
+  'ordered list': doc({
+    type: 'orderedList',
+    attrs: { start: 1 },
+    content: [
+      { type: 'listItem', content: [para(text('one'))] },
+      { type: 'listItem', content: [para(text('two'))] },
+    ],
+  }),
+
+  'task list (checkbox)': doc({
+    type: 'taskList',
+    content: [
+      {
+        type: 'taskItem',
+        attrs: { checked: true },
+        content: [para(text('done item'))],
+      },
+      {
+        type: 'taskItem',
+        attrs: { checked: false },
+        content: [para(text('todo item'))],
+      },
+    ],
+  }),
+
+  'blockquote': doc({
+    type: 'blockquote',
+    content: [para(text('a quoted line')), para(text('second quoted line'))],
+  }),
+
+  'callout (info)': doc({
+    type: 'callout',
+    attrs: { type: 'info' },
+    content: [para(text('an informational callout'))],
+  }),
+
+  'callout (warning)': doc({
+    type: 'callout',
+    attrs: { type: 'warning' },
+    content: [para(text('a warning callout'))],
+  }),
+
+  'code block (with language)': doc({
+    type: 'codeBlock',
+    attrs: { language: 'typescript' },
+    // A fenced code block's body is stored with a trailing newline (the form a
+    // markdown ``` fence round-trips to: marked normalizes the code text to end
+    // in "\n"). Authoring the fixture at that fixpoint mirrors how the engine
+    // normalizes-on-write (SPEC §11): codeBlock + `language` round-trip exactly.
+    content: [text('const a: number = 1;\nconsole.log(a);\n')],
+  }),
+
+  'horizontal rule': doc(
+    para(text('before')),
+    { type: 'horizontalRule' },
+    para(text('after')),
+  ),
+
+  'table (header row + cells)': doc({
+    type: 'table',
+    content: [
+      {
+        type: 'tableRow',
+        content: [
+          {
+            type: 'tableHeader',
+            attrs: { colspan: 1, rowspan: 1, colwidth: null },
+            content: [para(text('Name'))],
+          },
+          {
+            type: 'tableHeader',
+            attrs: { colspan: 1, rowspan: 1, colwidth: null },
+            content: [para(text('Value'))],
+          },
+        ],
+      },
+      {
+        type: 'tableRow',
+        content: [
+          {
+            type: 'tableCell',
+            attrs: { colspan: 1, rowspan: 1, colwidth: null },
+            content: [para(text('alpha'))],
+          },
+          {
+            type: 'tableCell',
+            attrs: { colspan: 1, rowspan: 1, colwidth: null },
+            content: [para(text('1'))],
+          },
+        ],
+      },
+    ],
+  }),
+
+  // --- editor-ext nodes/marks beyond the original corpus (item #7) ----------
+  // Each of these was verified to round-trip CLEANLY through the real gate
+  // (export -> markdown -> import -> editor-ext Yjs write path). Fixtures are
+  // pre-authored at the engine's normalize-on-write fixpoint (SPEC §11), e.g.
+  // details carries the materialized `open:false`, and color marks use the
+  // `rgb(...)` form the HTML re-parser normalizes to.
+
+  'mention (user)': doc(
+    para(
+      text('hi '),
+      {
+        type: 'mention',
+        attrs: {
+          id: 'user-123',
+          label: 'Alice',
+          entityType: 'user',
+          entityId: 'user-123',
+          creatorId: 'creator-1',
+        },
+      },
+      text(' there'),
+    ),
+  ),
+
+  'inline math': doc(
+    para(
+      text('inline '),
+      { type: 'mathInline', attrs: { text: 'x^2' } },
+      text(' math'),
+    ),
+  ),
+
+  'block math': doc({ type: 'mathBlock', attrs: { text: 'x^2 + y^2 = z^2' } }),
+
+  'details (collapsible)': doc({
+    type: 'details',
+    // `open:false` is the value editor-ext materializes on import; pre-authoring
+    // it puts the fixture at its round-trip fixpoint.
+    attrs: { open: false },
+    content: [
+      { type: 'detailsSummary', content: [text('Summary line')] },
+      { type: 'detailsContent', content: [para(text('hidden body'))] },
+    ],
+  }),
+
+  'highlight (mark, no color)': doc(
+    para(
+      text('a '),
+      text('highlighted', [{ type: 'highlight' }]),
+      text(' word'),
+    ),
+  ),
+
+  'highlight (mark, with color)': doc(
+    para(
+      text('a '),
+      text('red', [{ type: 'highlight', attrs: { color: 'rgb(255, 0, 0)' } }]),
+      text(' word'),
+    ),
+  ),
+
+  'subscript': doc(
+    para(text('H'), text('2', [{ type: 'subscript' }]), text('O')),
+  ),
+
+  'superscript': doc(
+    para(text('E=mc'), text('2', [{ type: 'superscript' }])),
+  ),
+
+  'text color (textStyle)': doc(
+    // The HTML re-parser normalizes CSS colors to the `rgb(...)` form, so the
+    // fixture pre-authors that form; a `#hex` color would round-trip to the
+    // equivalent rgb() and is therefore a value-normalization divergence (see
+    // the KNOWN DIVERGENCE block below).
+    para(text('green', [{ type: 'textStyle', attrs: { color: 'rgb(0, 255, 0)' } }])),
+  ),
+
+  'nested / mixed document': doc(
+    { type: 'heading', attrs: { level: 1 }, content: [text('Mixed')] },
+    para(
+      text('intro with '),
+      text('bold', [{ type: 'bold' }]),
+      text(' and a '),
+      text('link', [{ type: 'link', attrs: { href: 'https://example.com' } }]),
+      text('.'),
+    ),
+    {
+      type: 'bulletList',
+      content: [
+        {
+          type: 'listItem',
+          content: [
+            para(text('item with '), text('code', [{ type: 'code' }])),
+          ],
+        },
+        {
+          type: 'listItem',
+          content: [
+            para(text('item with sublist')),
+            {
+              type: 'bulletList',
+              content: [
+                { type: 'listItem', content: [para(text('nested a'))] },
+                { type: 'listItem', content: [para(text('nested b'))] },
+              ],
+            },
+          ],
+        },
+      ],
+    },
+    {
+      type: 'callout',
+      attrs: { type: 'success' },
+      content: [
+        para(text('callout body')),
+        { type: 'codeBlock', attrs: { language: 'bash' }, content: [text('echo hi\n')] },
+      ],
+    },
+    {
+      type: 'blockquote',
+      content: [para(text('quote at the end'))],
+    },
+  ),
+
+  // Atom embeds that carry no inline text: they must round-trip via their
+  // schema-matching HTML (data-type div), NOT a literal that re-imports as plain
+  // text. `subpages` used to export as the literal "{{SUBPAGES}}" and came back
+  // as visible text on the page (red-team round-trip data loss) — this locks it.
+  // editor-ext materializes the `recursive: false` default on import, so the
+  // fixture pre-authors it to sit at the round-trip fixpoint (matches the other
+  // default-materializing fixtures above).
+  'subpages embed': doc({ type: 'subpages', attrs: { recursive: false } }),
+};
+
+describe('git-sync converter §13.1 idempotency gate (editor-ext schema)', () => {
+  for (const [name, original] of Object.entries(CORPUS)) {
+    it(`round-trips losslessly: ${name}`, async () => {
+      const { md, canonOriginal, canonNormalized } = await runGate(original);
+
+      const equal = docsCanonicallyEqual(original, canonNormalized);
+      if (!equal) {
+        // Surface a readable diff so a real divergence is actionable.
+        // eslint-disable-next-line no-console
+        console.error(
+          `\n[GATE FAIL] ${name}\n--- markdown ---\n${md}\n` +
+            `--- canonical original ---\n${JSON.stringify(canonOriginal, null, 2)}\n` +
+            `--- canonical round-tripped ---\n${JSON.stringify(canonNormalized, null, 2)}\n`,
+        );
+      }
+      expect(equal).toBe(true);
+    });
+  }
+});
+
+// ---------------------------------------------------------------------------
+// KNOWN DIVERGENCE — images (isolated so it does NOT silently weaken the gate).
+//
+// This is NOT a schema-name divergence: the `image` NODE itself round-trips
+// through editor-ext fine (it survives toYdoc under the real tiptapExtensions).
+// The loss is intrinsic to MARKDOWN, the on-disk transport format git-sync uses:
+//
+//   1. `convertProseMirrorToMarkdown` emits a standard `![alt](src)` image
+//      (markdown-converter.ts case "image"). Standard markdown image syntax has
+//      no way to express `width` / `height` / `align`, so those attrs are
+//      DROPPED on export and cannot be recovered on import.
+//   2. A block-level image is hoisted out of its line by the HTML re-parser,
+//      leaving a leading EMPTY paragraph (the same block-image-hoist limitation
+//      documented in packages/git-sync/test/fixtures/known-limitations).
+//
+// The gate documents the EXACT lossy shape below. If the converter is ever
+// taught to preserve image dimensions (e.g. by emitting an HTML <img> with
+// data-* attrs, as it already does for video/diagrams), these assertions flip
+// and the image fixture should be promoted into the green CORPUS above.
+// ---------------------------------------------------------------------------
+describe('git-sync converter §13.1 image dimensions preserved (was KNOWN DIVERGENCE)', () => {
+  const imageDoc = doc({
+    type: 'image',
+    attrs: {
+      src: 'https://example.com/pic.png',
+      width: 640,
+      height: 480,
+      align: 'center',
+    },
+  });
+
+  it('preserves width/height/align by exporting an HTML <img> (PR #119 round-trip fix)', async () => {
+    const { md, canonNormalized } = await runGate(imageDoc);
+
+    // A top-level image carrying layout attrs is now exported as a schema-
+    // matching HTML <img> (the same path video/diagrams already use), so the
+    // dimensions and alignment survive the round trip instead of collapsing to
+    // bare `![](src)`.
+    expect(md.trim()).toBe(
+      '<img src="https://example.com/pic.png" width="640" height="480" align="center">',
+    );
+
+    // The round-tripped image keeps src + the layout attrs. width/height are
+    // re-imported as strings (matching the video/audio/pdf string convention),
+    // so assert the values rather than the JS type.
+    const imgAttrs = (canonNormalized as any).content[0].attrs;
+    expect((canonNormalized as any).content[0].type).toBe('image');
+    expect(imgAttrs.src).toBe('https://example.com/pic.png');
+    expect(imgAttrs.align).toBe('center');
+    expect(String(imgAttrs.width)).toBe('640');
+    expect(String(imgAttrs.height)).toBe('480');
+  });
+});
+
+// ---------------------------------------------------------------------------
+// KNOWN DIVERGENCE — text alignment (item #7; isolated, not silently dropped).
+//
+// editor-ext registers TextAlign for heading+paragraph, and the SERVER schema
+// fully supports it — the loss is intrinsic to the MARKDOWN transport:
+//
+//   • A paragraph's `textAlign` is EXPORTED as `<div align="...">text</div>`
+//     (markdown-converter case "paragraph"), but on import the converter's
+//     docmost-schema declares `textAlign` WITHOUT a parseHTML mapping, so the
+//     `align` attribute is never recovered -> it imports as `textAlign:null`
+//     and canonicalizes away. A heading's alignment is not even exported.
+//   • Therefore any non-default alignment is dropped on a full round trip.
+//
+// If the converter is ever taught to parse `align`/`text-align` back onto the
+// block, this assertion flips and an aligned-paragraph fixture should be
+// promoted into the green CORPUS above.
+// ---------------------------------------------------------------------------
+describe('git-sync converter §13.1 KNOWN DIVERGENCE (text alignment dropped)', () => {
+  it('drops a paragraph textAlign on the markdown round trip', async () => {
+    const alignedDoc = doc({
+      type: 'paragraph',
+      attrs: { textAlign: 'center' },
+      content: [text('centered')],
+    });
+
+    const { canonNormalized } = await runGate(alignedDoc);
+
+    // The round-tripped paragraph carries no alignment.
+    expect(canonNormalized).toEqual({
+      type: 'doc',
+      content: [{ type: 'paragraph', content: [{ type: 'text', text: 'centered' }] }],
+    });
+    expect(docsCanonicallyEqual(alignedDoc, canonNormalized)).toBe(false);
+  });
+
+  it('drops a heading textAlign (headings do not export alignment at all)', async () => {
+    const alignedHeading = doc({
+      type: 'heading',
+      attrs: { level: 2, textAlign: 'center' },
+      content: [text('centered heading')],
+    });
+
+    const { md, canonNormalized } = await runGate(alignedHeading);
+
+    // Export is a plain markdown heading — no alignment syntax.
+    expect(md.trim()).toBe('## centered heading');
+    expect(docsCanonicallyEqual(alignedHeading, canonNormalized)).toBe(false);
+  });
+});
+
+// ---------------------------------------------------------------------------
+// KNOWN DIVERGENCE — textStyle color is VALUE-NORMALIZED, not lost (item #7).
+//
+// The textStyle/color mark itself round-trips (the green CORPUS has the rgb()
+// form). But a `#hex` color is normalized to the equivalent `rgb(...)` string
+// by the HTML re-parser on import, and canonicalize.ts does NOT normalize color
+// formats — so a `#hex` original is not STRING-identical to its round trip even
+// though the color is semantically preserved. Locked here so the boundary is
+// explicit: author color fixtures in rgb() form to stay in the green corpus.
+// ---------------------------------------------------------------------------
+describe('git-sync converter §13.1 KNOWN DIVERGENCE (textStyle color #hex -> rgb)', () => {
+  it('normalizes a #hex text color to rgb() (semantically preserved, string-divergent)', async () => {
+    const hexDoc = doc(
+      para(text('green', [{ type: 'textStyle', attrs: { color: '#00ff00' } }])),
+    );
+
+    const { canonNormalized } = await runGate(hexDoc);
+
+    // Color survives, but as the normalized rgb() string.
+    expect(canonNormalized).toEqual({
+      type: 'doc',
+      content: [
+        {
+          type: 'paragraph',
+          content: [
+            {
+              type: 'text',
+              text: 'green',
+              marks: [{ type: 'textStyle', attrs: { color: 'rgb(0, 255, 0)' } }],
+            },
+          ],
+        },
+      ],
+    });
+    // Not string-identical to the #hex original.
+    expect(docsCanonicallyEqual(hexDoc, canonNormalized)).toBe(false);
+  });
+});

apps/server/src/collaboration/merge/lcs.ts

@@ -0,0 +1,26 @@
+/**
+ * Backward-filled LCS length table for sequences `a` and `b`: `dp[i][j]` is the
+ * length of the longest common subsequence of the suffixes `a[i:]` and `b[j:]`.
+ * O(n*m) time/space — fine for page block counts.
+ *
+ * Shared by the two-way block diff (`yjs-body-merge.diffBlocks`) and the
+ * three-way merge planner (`three-way-merge.lcsPairs`) so the (identical) table
+ * construction lives in ONE place; each caller does its own traceback over the
+ * returned table.
+ */
+export function buildLcsTable(a: string[], b: string[]): number[][] {
+  const n = a.length;
+  const m = b.length;
+  const dp: number[][] = Array.from({ length: n + 1 }, () =>
+    new Array(m + 1).fill(0),
+  );
+  for (let i = n - 1; i >= 0; i--) {
+    for (let j = m - 1; j >= 0; j--) {
+      dp[i][j] =
+        a[i] === b[j]
+          ? dp[i + 1][j + 1] + 1
+          : Math.max(dp[i + 1][j], dp[i][j + 1]);
+    }
+  }
+  return dp;
+}

apps/server/src/collaboration/merge/redteam-three-way.spec.ts

@@ -0,0 +1,20 @@
+import { diff3Plan, type Pick } from './three-way-merge';
+
+// Materialize a plan into the merged key sequence for assertion.
+function apply(plan: Pick[], live: string[], target: string[]): string[] {
+  return plan.map((p) => (p.src === 'live' ? live[p.index] : target[p.index]));
+}
+
+const merge = (o: string[], a: string[], b: string[]): string[] =>
+  apply(diff3Plan(o, a, b), a, b);
+
+describe('diff3Plan red-team #9 (human edit + adjacent git insert)', () => {
+  it('keeps human block-2 edit AND applies git insert of 2.5', () => {
+    // base:   1 2 3
+    // live:   1 H 3   (human rewrote block 2)
+    // target: 1 2 2.5 3 (git inserted 2.5 after block 2)
+    expect(
+      merge(['1', '2', '3'], ['1', 'H', '3'], ['1', '2', '2.5', '3']),
+    ).toEqual(['1', 'H', '2.5', '3']);
+  });
+});

apps/server/src/collaboration/merge/three-way-merge.spec.ts

@@ -0,0 +1,159 @@
+import {
+  diff3Plan,
+  diff3PlanWithConflicts,
+  type Pick,
+} from './three-way-merge';
+
+// Materialize a plan into the merged key sequence for assertion.
+function apply(plan: Pick[], live: string[], target: string[]): string[] {
+  return plan.map((p) => (p.src === 'live' ? live[p.index] : target[p.index]));
+}
+
+const merge = (o: string[], a: string[], b: string[]): string[] =>
+  apply(diff3Plan(o, a, b), a, b);
+
+describe('diff3Plan (block-level three-way merge)', () => {
+  it('identical on all three sides -> unchanged (all from live)', () => {
+    const plan = diff3Plan(['1', '2', '3'], ['1', '2', '3'], ['1', '2', '3']);
+    expect(plan.every((p) => p.src === 'live')).toBe(true);
+    expect(apply(plan, ['1', '2', '3'], ['1', '2', '3'])).toEqual(['1', '2', '3']);
+  });
+
+  it('git changed a block the human did not -> takes git', () => {
+    expect(merge(['1', '2', '3'], ['1', '2', '3'], ['1', '9', '3'])).toEqual([
+      '1',
+      '9',
+      '3',
+    ]);
+  });
+
+  it('human changed a block git did not -> KEEPS the human edit (the core 3-way win)', () => {
+    expect(merge(['1', '2', '3'], ['1', 'H', '3'], ['1', '2', '3'])).toEqual([
+      '1',
+      'H',
+      '3',
+    ]);
+  });
+
+  // Bug #2 observability: diff3PlanWithConflicts reports SAME-BLOCK conflicts so
+  // the caller can surface the "git wins" loss (log + history pin) instead of
+  // dropping the human side silently.
+  describe('diff3PlanWithConflicts (same-block conflict reporting)', () => {
+    it('reports 0 conflicts when sides changed DIFFERENT blocks (clean merge)', () => {
+      const r = diff3PlanWithConflicts(
+        ['1', '2', '3'],
+        ['H', '2', '3'],
+        ['1', '2', 'G'],
+      );
+      expect(r.conflicts).toBe(0);
+      expect(apply(r.picks, ['H', '2', '3'], ['1', '2', 'G'])).toEqual([
+        'H',
+        '2',
+        'G',
+      ]);
+    });
+
+    it('reports 1 conflict and git wins when BOTH rewrote the SAME block', () => {
+      const r = diff3PlanWithConflicts(
+        ['1', '2', '3'],
+        ['1', 'H', '3'], // human rewrote block 2
+        ['1', 'G', '3'], // git rewrote block 2
+      );
+      expect(r.conflicts).toBe(1);
+      // Git wins the contested block; the human 'H' is NOT in the picks.
+      expect(apply(r.picks, ['1', 'H', '3'], ['1', 'G', '3'])).toEqual([
+        '1',
+        'G',
+        '3',
+      ]);
+    });
+
+    it('does NOT count a git-only region (no human content to lose) as a conflict', () => {
+      const r = diff3PlanWithConflicts(
+        ['1', '2', '3'],
+        ['1', '2', '3'], // human unchanged
+        ['1', '9', '3'], // git rewrote block 2
+      );
+      expect(r.conflicts).toBe(0);
+    });
+  });
+
+  it('human and git changed DIFFERENT blocks -> both preserved', () => {
+    // human rewrote block 1, git rewrote block 3.
+    expect(merge(['1', '2', '3'], ['H', '2', '3'], ['1', '2', 'G'])).toEqual([
+      'H',
+      '2',
+      'G',
+    ]);
+  });
+
+  it('human inserted a block AND git changed a different block -> both preserved', () => {
+    expect(
+      merge(['1', '2', '3'], ['1', '1.5', '2', '3'], ['1', '2', 'G']),
+    ).toEqual(['1', '1.5', '2', 'G']);
+  });
+
+  it('both changed the SAME block -> conflict resolves to git', () => {
+    expect(merge(['1', '2', '3'], ['1', 'H', '3'], ['1', 'G', '3'])).toEqual([
+      '1',
+      'G',
+      '3',
+    ]);
+  });
+
+  it('both made the SAME edit -> that edit (no duplication)', () => {
+    expect(merge(['1', '2', '3'], ['1', 'X', '3'], ['1', 'X', '3'])).toEqual([
+      '1',
+      'X',
+      '3',
+    ]);
+  });
+
+  it('human deleted a block git left alone -> deletion preserved', () => {
+    expect(merge(['1', '2', '3'], ['1', '3'], ['1', '2', '3'])).toEqual([
+      '1',
+      '3',
+    ]);
+  });
+
+  it('git deleted a block the human left alone -> deletion applied', () => {
+    expect(merge(['1', '2', '3'], ['1', '2', '3'], ['1', '3'])).toEqual([
+      '1',
+      '3',
+    ]);
+  });
+
+  it('both deleted the same block -> gone (no conflict)', () => {
+    expect(merge(['1', '2', '3'], ['1', '3'], ['1', '3'])).toEqual(['1', '3']);
+  });
+
+  it('git appended a trailing block -> appended', () => {
+    expect(merge(['1', '2'], ['1', '2'], ['1', '2', '3'])).toEqual([
+      '1',
+      '2',
+      '3',
+    ]);
+  });
+
+  it('human appended a trailing block git did not -> kept', () => {
+    expect(merge(['1', '2'], ['1', '2', '3'], ['1', '2'])).toEqual([
+      '1',
+      '2',
+      '3',
+    ]);
+  });
+
+  it('empty base, git provides content (brand-new page body) -> git content', () => {
+    expect(merge([], [], ['1', '2'])).toEqual(['1', '2']);
+  });
+
+  it('git changed block 1, human edited block 3, far apart -> both kept', () => {
+    expect(
+      merge(
+        ['a', 'b', 'c', 'd', 'e'],
+        ['a', 'b', 'c', 'd', 'E'],
+        ['A', 'b', 'c', 'd', 'e'],
+      ),
+    ).toEqual(['A', 'b', 'c', 'd', 'E']);
+  });
+});

apps/server/src/collaboration/merge/three-way-merge.ts

@@ -0,0 +1,274 @@
+/**
+ * Pure block-level THREE-WAY merge planner (diff3) over arrays of opaque block
+ * keys. Used by the git-sync body write to merge an incoming git body into the
+ * live page using the last-synced version as the common ancestor (review #5):
+ *
+ *   - a block only the human changed (live != base, git == base) -> keep LIVE
+ *   - a block only git changed       (git != base, live == base) -> take GIT
+ *   - a block both sides changed (a real conflict)               -> GIT wins
+ *   - inserts/deletes from either side are preserved when unambiguous
+ *
+ * Content-agnostic: it works on string keys and returns the merged block order as
+ * picks ({ src: 'live'|'target', index }) — the caller (the Yjs applier)
+ * materializes them — so the whole algorithm is unit-testable on plain arrays.
+ *
+ * Algorithm: anchor on base blocks present (unchanged) in BOTH live and target
+ * (their LCS-with-base intersection). Between consecutive anchors lies one region
+ * the human and/or git rewrote; resolve each region three-way. Stable anchor
+ * blocks are emitted from LIVE so the applier keeps the existing Yjs block
+ * instances (and the human's in-flight edits) in place.
+ *
+ * LOCATION (deferred): this and its `lcs.ts` sibling are pure, framework-free and
+ * could conceptually live in `packages/git-sync` (the engine). They are kept in
+ * the server integration on purpose: `packages/git-sync` is a VENDORED engine
+ * (pinned upstream, manually re-synced), so adding first-party files there
+ * complicates the re-sync story, and the only consumer today is the server. Move
+ * them into the engine only once the vendoring re-sync story is settled.
+ */
+
+import { buildLcsTable } from './lcs';
+
+/** Matched index pairs of the longest common subsequence of `a` and `b`. */
+function lcsPairs(a: string[], b: string[]): Array<[number, number]> {
+  const n = a.length;
+  const m = b.length;
+  const dp = buildLcsTable(a, b);
+  const pairs: Array<[number, number]> = [];
+  let i = 0;
+  let j = 0;
+  while (i < n && j < m) {
+    if (a[i] === b[j]) {
+      pairs.push([i, j]);
+      i++;
+      j++;
+    } else if (dp[i + 1][j] >= dp[i][j + 1]) {
+      i++;
+    } else {
+      j++;
+    }
+  }
+  return pairs;
+}
+
+/** o-index -> matched index in the other side (only for LCS-matched blocks). */
+function matchMap(pairs: Array<[number, number]>): Map<number, number> {
+  const m = new Map<number, number>();
+  for (const [o, x] of pairs) m.set(o, x);
+  return m;
+}
+
+/**
+ * One change `side` made to `base` within a region: base blocks `[oStart,oEnd)`
+ * were replaced by the side's blocks listed in `content` (region-local indices).
+ * A pure insert has `oStart === oEnd`; a pure delete has empty `content`.
+ */
+interface Hunk {
+  oStart: number;
+  oEnd: number;
+  content: number[];
+}
+
+/**
+ * Diff `o` against one side as a list of non-overlapping hunks (the base spans
+ * the side rewrote/inserted/deleted), derived from their LCS alignment.
+ */
+function buildHunks(o: string[], side: string[]): Hunk[] {
+  const pairs = lcsPairs(o, side); // [oIdx, sideIdx] kept (unchanged) blocks
+  const hunks: Hunk[] = [];
+  let prevO = -1;
+  let prevS = -1;
+  const flush = (curO: number, curS: number): void => {
+    const oStart = prevO + 1;
+    const oEnd = curO;
+    const content: number[] = [];
+    for (let s = prevS + 1; s < curS; s++) content.push(s);
+    if (oEnd > oStart || content.length > 0) hunks.push({ oStart, oEnd, content });
+  };
+  for (const [oIdx, sIdx] of pairs) {
+    flush(oIdx, sIdx);
+    prevO = oIdx;
+    prevS = sIdx;
+  }
+  flush(o.length, side.length);
+  return hunks;
+}
+
+/**
+ * Do two hunks (one per side) touch the same base region? Pure inserts only
+ * collide when nested strictly inside the other hunk's base span (or, for two
+ * inserts, at the same gap); changes sitting at a shared boundary do not.
+ */
+function hunksOverlap(a: Hunk, b: Hunk): boolean {
+  const aIns = a.oStart === a.oEnd;
+  const bIns = b.oStart === b.oEnd;
+  if (aIns && bIns) return a.oStart === b.oStart;
+  if (aIns) return b.oStart < a.oStart && a.oStart < b.oEnd;
+  if (bIns) return a.oStart < b.oStart && b.oStart < a.oEnd;
+  return Math.max(a.oStart, b.oStart) < Math.min(a.oEnd, b.oEnd);
+}
+
+interface LocalPick {
+  src: 'live' | 'target';
+  local: number;
+}
+
+/**
+ * Fine-grained three-way merge of ONE inter-anchor region. Combines the human's
+ * and git's NON-overlapping hunks (e.g. a human edit to one block plus a git
+ * insert/delete of OTHER blocks in the same region) so neither change is lost.
+ * Returns the merged region as region-local picks, or `null` when the two sides
+ * changed the SAME base block — a genuine conflict the caller resolves by the
+ * original all-or-nothing rule (git wins the whole region).
+ */
+function tryMergeRegion(
+  o: string[],
+  a: string[],
+  b: string[],
+): LocalPick[] | null {
+  const aHunks = buildHunks(o, a);
+  const bHunks = buildHunks(o, b);
+
+  // Any overlap between a human hunk and a git hunk is a real conflict; bail so
+  // the caller falls back to git-wins (preserving the original behavior).
+  for (const ah of aHunks) {
+    for (const bh of bHunks) {
+      if (hunksOverlap(ah, bh)) return null;
+    }
+  }
+
+  // Disjoint: live index of each base block that BOTH sides kept (stable).
+  const aKept = matchMap(lcsPairs(o, a)); // base index -> live index
+
+  const out: LocalPick[] = [];
+  let pa = 0;
+  let pb = 0;
+  let oi = 0;
+  while (oi < o.length || pa < aHunks.length || pb < bHunks.length) {
+    const ah = pa < aHunks.length ? aHunks[pa] : null;
+    const bh = pb < bHunks.length ? bHunks[pb] : null;
+    const nextStart = Math.min(
+      ah ? ah.oStart : o.length,
+      bh ? bh.oStart : o.length,
+    );
+
+    // Emit stable base blocks (kept by both) until the next hunk, from LIVE.
+    while (oi < nextStart) {
+      out.push({ src: 'live', local: aKept.get(oi) as number });
+      oi++;
+    }
+    if (!ah && !bh) break;
+
+    // Apply the hunk at oi. When both sides act here they are disjoint, so the
+    // pure-insert (oEnd === oi) is emitted before the side that consumes base oi.
+    const aHere = ah !== null && ah.oStart === oi;
+    const bHere = bh !== null && bh.oStart === oi;
+    let useA: boolean;
+    if (aHere && bHere) {
+      useA = ah!.oEnd === oi; // insert side first; otherwise either order is fine
+    } else {
+      useA = aHere;
+    }
+    const h = (useA ? ah : bh) as Hunk;
+    const src: 'live' | 'target' = useA ? 'live' : 'target';
+    for (const idx of h.content) out.push({ src, local: idx });
+    oi = h.oEnd;
+    if (useA) pa++;
+    else pb++;
+  }
+  return out;
+}
+
+export interface Pick {
+  src: 'live' | 'target';
+  index: number;
+}
+
+/**
+ * The merged block order PLUS how many regions resolved as a genuine SAME-BLOCK
+ * conflict (both sides rewrote the same base block — `tryMergeRegion` returned
+ * null and git won the whole region, so the live/human version of those blocks
+ * is NOT in `picks`). `conflicts > 0` is the OBSERVABLE signal the caller uses to
+ * surface "git won a concurrent same-block edit" (log it + pin the human
+ * baseline to page history) instead of dropping the human side silently.
+ */
+export interface Diff3Result {
+  picks: Pick[];
+  conflicts: number;
+}
+
+/**
+ * Three-way merge of base `o`, live `a`, target `b` (arrays of block keys).
+ * Returns the merged block order as picks from live/target. Thin wrapper over
+ * `diff3PlanWithConflicts` (kept for the existing pure-array callers/tests).
+ */
+export function diff3Plan(o: string[], a: string[], b: string[]): Pick[] {
+  return diff3PlanWithConflicts(o, a, b).picks;
+}
+
+/**
+ * Like `diff3Plan` but also reports the SAME-BLOCK conflict count (see
+ * `Diff3Result`). A region where both the human and git rewrote the same base
+ * block cannot be merged automatically; the rule is deterministic — GIT WINS the
+ * whole region — but the human's version of those blocks is then absent from the
+ * picks, so we count it so the caller can make the loss observable/recoverable
+ * rather than silent (the documented conflict contract).
+ */
+export function diff3PlanWithConflicts(
+  o: string[],
+  a: string[],
+  b: string[],
+): Diff3Result {
+  const oToA = matchMap(lcsPairs(o, a));
+  const oToB = matchMap(lcsPairs(o, b));
+
+  const res: Pick[] = [];
+  let conflicts = 0;
+  let oi = 0;
+  let ai = 0;
+  let bi = 0;
+
+  for (;;) {
+    // Next anchor: a base block present (unchanged) in BOTH live and target.
+    let anchor = oi;
+    while (anchor < o.length && !(oToA.has(anchor) && oToB.has(anchor))) {
+      anchor++;
+    }
+    const aEnd = anchor < o.length ? (oToA.get(anchor) as number) : a.length;
+    const bEnd = anchor < o.length ? (oToB.get(anchor) as number) : b.length;
+
+    // Resolve the region [oi,anchor) that one or both sides rewrote/inserted.
+    // Try a fine-grained three-way merge first so a human block-edit survives a
+    // git insert/delete of OTHER blocks in the same region; only a genuine
+    // same-block conflict (null) falls back to the original git-wins rule.
+    const merged = tryMergeRegion(
+      o.slice(oi, anchor),
+      a.slice(ai, aEnd),
+      b.slice(bi, bEnd),
+    );
+    if (merged) {
+      for (const p of merged) {
+        res.push(
+          p.src === 'live'
+            ? { src: 'live', index: ai + p.local }
+            : { src: 'target', index: bi + p.local },
+        );
+      }
+    } else {
+      // SAME-BLOCK CONFLICT: count it ONLY when the human side actually had
+      // content in this region that git's win discards (live region non-empty).
+      // A region only git rewrote (live region empty) is not a human loss.
+      if (aEnd > ai) conflicts++;
+      for (let k = bi; k < bEnd; k++) res.push({ src: 'target', index: k });
+    }
+
+    if (anchor >= o.length) break;
+
+    // Emit the stable anchor block from LIVE, then advance past it on all sides.
+    res.push({ src: 'live', index: aEnd });
+    ai = aEnd + 1;
+    bi = bEnd + 1;
+    oi = anchor + 1;
+  }
+
+  return { picks: res, conflicts };
+}

apps/server/src/collaboration/merge/yjs-body-merge.callout.spec.ts

@@ -0,0 +1,171 @@
+import { TiptapTransformer } from '@hocuspocus/transformer';
+import * as Y from 'yjs';
+import {
+  markdownToProseMirror,
+  convertProseMirrorToMarkdown,
+} from '@docmost/git-sync';
+
+import { tiptapExtensions } from '../collaboration.util';
+import { mergeXmlFragments, mergeXmlFragments3Way } from './yjs-body-merge';
+
+/**
+ * Regression for the QA #119 callout findings (body-duplication re-verify +
+ * "callout strips the whole body"). These reproduce the ACTUAL live merge path:
+ *
+ *   live  = TiptapTransformer.toYdoc(editor JSON, tiptapExtensions)   (the
+ *           collaboration server's materialization — schema defaults stamped)
+ *   git   = toYdoc(markdownToProseMirror(convertProseMirrorToMarkdown(editor)))
+ *           (the engine round-trip the push side feeds into writePageBody)
+ *
+ * A page containing a callout (with a neighbouring heading + paragraphs) must:
+ *   - merge with ZERO ops on an unchanged resync (no duplication — bug #1), and
+ *   - NEVER lose blocks / collapse to empty (no strip — bug #2),
+ * across repeated cycles, for every editor-canonical callout type.
+ */
+
+const toYdoc = (content: unknown[]) =>
+  TiptapTransformer.toYdoc(
+    { type: 'doc', content },
+    'default',
+    tiptapExtensions as any,
+  );
+
+const blockTypes = (f: Y.XmlFragment) =>
+  f.toArray().map((n: any) => n.nodeName);
+
+function editorPage(calloutType: string) {
+  return [
+    {
+      type: 'heading',
+      attrs: { id: 'h1', level: 1 },
+      content: [{ type: 'text', text: 'Title here' }],
+    },
+    {
+      type: 'paragraph',
+      attrs: { id: 'p1' },
+      content: [{ type: 'text', text: 'Para before callout' }],
+    },
+    {
+      type: 'callout',
+      attrs: { type: calloutType },
+      content: [
+        {
+          type: 'paragraph',
+          attrs: { id: 'pc' },
+          content: [{ type: 'text', text: 'Inside the callout' }],
+        },
+      ],
+    },
+    {
+      type: 'paragraph',
+      attrs: { id: 'p2' },
+      content: [{ type: 'text', text: 'Para after callout' }],
+    },
+  ];
+}
+
+async function gitRoundTrip(content: unknown[]): Promise<any[]> {
+  const md = await convertProseMirrorToMarkdown({ type: 'doc', content });
+  const json = await markdownToProseMirror(md);
+  return json.content;
+}
+
+describe('git-sync callout merge is idempotent + non-destructive (QA #119)', () => {
+  for (const type of ['info', 'note', 'warning', 'danger', 'success', 'default']) {
+    it(`callout(${type}) resyncs with 0 ops and never strips the body`, async () => {
+      const editor = editorPage(type);
+      const gitContent = await gitRoundTrip(editor);
+
+      const liveDoc = toYdoc(editor);
+      const live = liveDoc.getXmlFragment('default');
+      const before = live.toArray().length;
+      expect(before).toBe(4);
+
+      // 2-way: live vs the git round-trip -> no-op (no dup, no strip).
+      let applied = -1;
+      liveDoc.transact(() => {
+        applied = mergeXmlFragments(live, toYdoc(gitContent).getXmlFragment('default'));
+      });
+      expect(applied).toBe(0);
+      expect(live.toArray().length).toBe(before);
+
+      // 3-way across 4 cycles with base == git (the steady-state) -> stable.
+      for (let cycle = 0; cycle < 4; cycle++) {
+        let a = -1;
+        liveDoc.transact(() => {
+          a = mergeXmlFragments3Way(
+            live,
+            toYdoc(gitContent).getXmlFragment('default'),
+            toYdoc(gitContent).getXmlFragment('default'),
+          );
+        });
+        expect(a).toBe(0);
+        expect(live.toArray().length).toBe(before);
+        expect(blockTypes(live)).toEqual([
+          'heading',
+          'paragraph',
+          'callout',
+          'paragraph',
+        ]);
+      }
+    });
+  }
+
+  it('3-way with a stale base (callout JUST added) keeps the callout + neighbours', async () => {
+    // base = the previously-synced version WITHOUT the callout (git round-trip);
+    // the human just inserted the callout -> the merge must KEEP everything.
+    const prev = [
+      { type: 'heading', attrs: { id: 'h1', level: 1 }, content: [{ type: 'text', text: 'Title here' }] },
+      { type: 'paragraph', attrs: { id: 'p1' }, content: [{ type: 'text', text: 'Para before callout' }] },
+      { type: 'paragraph', attrs: { id: 'p2' }, content: [{ type: 'text', text: 'Para after callout' }] },
+    ];
+    const editor = editorPage('info');
+    const baseContent = await gitRoundTrip(prev);
+    const gitContent = await gitRoundTrip(editor);
+
+    const liveDoc = toYdoc(editor);
+    const live = liveDoc.getXmlFragment('default');
+    liveDoc.transact(() => {
+      mergeXmlFragments3Way(
+        live,
+        toYdoc(gitContent).getXmlFragment('default'),
+        toYdoc(baseContent).getXmlFragment('default'),
+      );
+    });
+    // Body survives in full — NOT stripped to empty / a lone paragraph.
+    expect(blockTypes(live)).toEqual([
+      'heading',
+      'paragraph',
+      'callout',
+      'paragraph',
+    ]);
+  });
+});
+
+describe('git-sync callout type fidelity (QA "callout type -> [!info]")', () => {
+  for (const type of ['info', 'note', 'warning', 'danger', 'success', 'default']) {
+    it(`preserves callout type "${type}" across the engine round-trip`, async () => {
+      const content = editorPage(type);
+      const gitContent = await gitRoundTrip(content);
+      const co = gitContent.find((b: any) => b.type === 'callout');
+      expect(co?.attrs?.type).toBe(type);
+    });
+  }
+
+  it('maps a known GitHub/Obsidian alias to the editor banner (tip -> success)', async () => {
+    // `tip` is not a schema callout type — it is an input alias the editor itself
+    // maps onto the supported set (GITHUB_ALERT_TYPE_MAP: tip -> success). git-sync
+    // mirrors that so the ingest lands on the closest banner instead of flatly info.
+    const content = editorPage('tip');
+    const gitContent = await gitRoundTrip(content);
+    const co = gitContent.find((b: any) => b.type === 'callout');
+    expect(co?.attrs?.type).toBe('success');
+  });
+
+  it('flattens a genuinely unknown callout type to info', async () => {
+    const content = editorPage('banana'); // not a type and not a known alias
+    const gitContent = await gitRoundTrip(content);
+    const co = gitContent.find((b: any) => b.type === 'callout');
+    expect(co?.attrs?.type).toBe('info');
+  });
+});

apps/server/src/collaboration/merge/yjs-body-merge.idempotency.spec.ts

@@ -0,0 +1,198 @@
+import * as Y from 'yjs';
+
+import { mergeXmlFragments, mergeXmlFragments3Way } from './yjs-body-merge';
+
+/**
+ * Regression for the HIGH-severity runaway whole-body duplication: a page body
+ * was RE-APPENDED in full on every git-sync reconcile cycle, unbounded, with NO
+ * client connected.
+ *
+ * ROOT CAUSE (confirmed in-process against the real failing page): the LIVE Yjs
+ * document materializes the editor-schema default `indent: 0` on every
+ * paragraph/heading (and on the paragraph inside every list item, callout, and
+ * table cell), but a body re-imported from git — parsed from clean markdown —
+ * carries NO indent attribute. So every live block's comparison key differed from
+ * the same block coming back from git; the three-way merge could anchor on
+ * NOTHING, and the trailing unit that git's export already contained (but the
+ * merge could not match against the byte-identical live tail) was re-appended
+ * each cycle. Each grown export then diverged from the last-pushed base by one
+ * more unit — a self-sustaining loop.
+ *
+ * The fix normalizes the materialized default (`indent: 0`) out of the block key
+ * (the schema-derived `serializeXmlNode` normalization in yjs-body-merge.ts drops
+ * every attr equal to its ProseMirror-schema default; `indent: 0` is one such),
+ * so a live block compares equal to its git-round-tripped twin and the resync is
+ * a true no-op. The sibling `yjs-body-merge.schema-defaults.spec.ts` covers the
+ * rest of the bug class (image.align, link mark internal, …).
+ *
+ * These tests model that EXACTLY at the Yjs level: a LIVE fragment whose blocks
+ * carry `indent: 0` + block ids, versus a git-derived fragment of the SAME
+ * content with neither — for a body built from BYTE-IDENTICAL units that each
+ * contain a heading, a paragraph, a callout, and a table with empty cells (the
+ * trigger). RED before the fix (the merge applies > 0 ops and the body grows),
+ * GREEN after (0 ops, no growth).
+ */
+
+type Attrs = Record<string, string | number>;
+
+function el(
+  name: string,
+  attrs: Attrs,
+  children: (Y.XmlElement | Y.XmlText)[],
+) {
+  const e = new Y.XmlElement(name);
+  for (const [k, v] of Object.entries(attrs)) e.setAttribute(k, v as string);
+  if (children.length) e.insert(0, children);
+  return e;
+}
+
+function text(s: string): Y.XmlText {
+  const t = new Y.XmlText();
+  if (s) t.insert(0, s);
+  return t;
+}
+
+/**
+ * One byte-identical content unit (heading / paragraph / callout / table-with-
+ * empty-cells). `live` toggles the two things that exist ONLY in the live Yjs
+ * doc and NOT in a git round-trip: the materialized `indent: 0` default and the
+ * per-block `id`. `n` makes each unit's ids unique (as the editor would stamp)
+ * while keeping the visible CONTENT byte-identical across units.
+ */
+function unit(
+  live: boolean,
+  n: number,
+  headingText = 'Big Heading',
+): Y.XmlElement[] {
+  const ind: Attrs = live ? { indent: 0 } : {};
+  const id = (base: string): Attrs => (live ? { id: `${base}${n}` } : {});
+  const para = (attrs: Attrs, s: string) =>
+    el('paragraph', { ...attrs, ...ind }, [text(s)]);
+
+  const cell = (name: string) =>
+    el(name, { colspan: 1, rowspan: 1 }, [para({}, '')]);
+
+  return [
+    el('heading', { ...id('h'), level: 1, ...ind }, [text(headingText)]),
+    para(id('p'), 'Para with the same words'),
+    el('callout', { type: 'info' }, [para(id('c'), 'CalloutText here')]),
+    el('table', {}, [
+      el('tableRow', {}, [cell('tableHeader'), cell('tableHeader')]),
+      el('tableRow', {}, [cell('tableCell'), cell('tableCell')]),
+    ]),
+  ];
+}
+
+function fragmentOf(units: Y.XmlElement[][]): {
+  doc: Y.Doc;
+  frag: Y.XmlFragment;
+} {
+  const doc = new Y.Doc();
+  const frag = doc.getXmlFragment('default');
+  const blocks = units.flat();
+  if (blocks.length) frag.insert(0, blocks);
+  return { doc, frag };
+}
+
+const blockCount = (frag: Y.XmlFragment): number => frag.toArray().length;
+
+describe('git-sync reconcile import is idempotent (no whole-body duplication)', () => {
+  const UNITS = 3;
+
+  it('3-way: identical content, live carries indent:0, base stale-by-one -> 0 ops, no growth', () => {
+    // LIVE: the editor-stamped Yjs doc (indent:0 + ids on every block).
+    const { doc: liveDoc, frag: live } = fragmentOf(
+      Array.from({ length: UNITS }, (_, i) => unit(true, i)),
+    );
+    // INCOMING (git export -> re-import): same content, NO indent / ids.
+    const { frag: incoming } = fragmentOf(
+      Array.from({ length: UNITS }, (_, i) => unit(false, i)),
+    );
+    // BASE = last-pushed file, lagging by ONE unit (the realistic divergence
+    // that drives the trailing insert-vs-insert).
+    const { frag: base } = fragmentOf(
+      Array.from({ length: UNITS - 1 }, (_, i) => unit(false, i)),
+    );
+
+    const before = blockCount(live);
+    let applied = -1;
+    liveDoc.transact(() => {
+      applied = mergeXmlFragments3Way(live, incoming, base);
+    });
+
+    expect(applied).toBe(0);
+    expect(blockCount(live)).toBe(before);
+  });
+
+  it('3-way is a fixpoint across repeated cycles (does not grow)', () => {
+    const { doc: liveDoc, frag: live } = fragmentOf(
+      Array.from({ length: UNITS }, (_, i) => unit(true, i)),
+    );
+    const incomingUnits = () =>
+      fragmentOf(Array.from({ length: UNITS }, (_, i) => unit(false, i))).frag;
+    const baseUnits = () =>
+      fragmentOf(Array.from({ length: UNITS - 1 }, (_, i) => unit(false, i)))
+        .frag;
+
+    const before = blockCount(live);
+    for (let cycle = 0; cycle < 5; cycle++) {
+      let applied = -1;
+      liveDoc.transact(() => {
+        applied = mergeXmlFragments3Way(live, incomingUnits(), baseUnits());
+      });
+      expect(applied).toBe(0);
+      expect(blockCount(live)).toBe(before);
+    }
+  });
+
+  it('2-way: identical content, live carries indent:0 -> 0 ops, no growth', () => {
+    const { doc: liveDoc, frag: live } = fragmentOf(
+      Array.from({ length: UNITS }, (_, i) => unit(true, i)),
+    );
+    const { frag: incoming } = fragmentOf(
+      Array.from({ length: UNITS }, (_, i) => unit(false, i)),
+    );
+
+    const before = blockCount(live);
+    let applied = -1;
+    liveDoc.transact(() => {
+      applied = mergeXmlFragments(live, incoming);
+    });
+
+    expect(applied).toBe(0);
+    expect(blockCount(live)).toBe(before);
+  });
+
+  it('does NOT regress real edits: a git change to one block still lands', () => {
+    const { doc: liveDoc, frag: live } = fragmentOf(
+      Array.from({ length: UNITS }, (_, i) => unit(true, i)),
+    );
+    const base = fragmentOf(
+      Array.from({ length: UNITS }, (_, i) => unit(false, i)),
+    ).frag;
+    // git edits the heading text of the LAST unit.
+    const incoming = fragmentOf(
+      Array.from({ length: UNITS }, (_, i) =>
+        unit(false, i, i === UNITS - 1 ? 'EDITED Heading' : 'Big Heading'),
+      ),
+    ).frag;
+
+    const before = blockCount(live);
+    liveDoc.transact(() => {
+      mergeXmlFragments3Way(live, incoming, base);
+    });
+
+    // The edit landed, and the body did NOT grow (one block changed in place).
+    const headings = live
+      .toArray()
+      .filter((b) => (b as Y.XmlElement).nodeName === 'heading')
+      .map((b) =>
+        (b as Y.XmlElement)
+          .toArray()
+          .map((c) => (c as Y.XmlText).toString())
+          .join(''),
+      );
+    expect(headings).toContain('EDITED Heading');
+    expect(blockCount(live)).toBe(before);
+  });
+});

apps/server/src/collaboration/merge/yjs-body-merge.schema-defaults.spec.ts

@@ -0,0 +1,316 @@
+import { TiptapTransformer } from '@hocuspocus/transformer';
+import * as Y from 'yjs';
+
+import { tiptapExtensions } from '../collaboration.util';
+import { mergeXmlFragments, mergeXmlFragments3Way } from './yjs-body-merge';
+
+/**
+ * Regression for the BUG CLASS behind the runaway whole-body duplication: the
+ * point-fix (7a7b840e) only normalized `indent: 0`, but the SAME divergence
+ * recurs for every attribute whose editor-ext (server) schema default the live
+ * Yjs doc MATERIALIZES while the git round-trip — which comes through the engine
+ * schema (different, usually null, defaults) plus `y-prosemirror`'s null-attr
+ * dropping — does NOT carry. Confirmed triggers beyond `indent`:
+ *
+ *   - `image.align`   : editor-ext default "center" (materialized) vs engine
+ *                       default null (dropped) -> element-attr divergence.
+ *   - link mark `internal`: editor-ext default false (materialized) vs engine
+ *                       default null -> MARK-attr divergence (the prior denylist
+ *                       could not reach marks at all — they are serialized raw in
+ *                       the XmlText delta).
+ *
+ * `highlight.colorName` is normalized too (defense-in-depth); it is NOT a strong
+ * real-world trigger because BOTH schemas default it to null, but the schema-
+ * derived normalization handles it for free and stays idempotent.
+ *
+ * The fix derives the defaults from the ACTUAL ProseMirror schema (getSchema of
+ * the server tiptapExtensions) and drops any element- OR mark-attribute equal to
+ * its schema default (or null/undefined) from the block comparison key — so a
+ * live block compares equal to its git-round-tripped twin and an unchanged
+ * resync applies 0 ops. RED before the fix (keys diverge -> ops > 0 / growth),
+ * GREEN after.
+ */
+
+type Attrs = Record<string, unknown>;
+
+function el(
+  name: string,
+  attrs: Attrs,
+  children: (Y.XmlElement | Y.XmlText)[],
+): Y.XmlElement {
+  const e = new Y.XmlElement(name);
+  for (const [k, v] of Object.entries(attrs)) e.setAttribute(k, v as string);
+  if (children.length) e.insert(0, children);
+  return e;
+}
+
+/** Text carrying marks, as the live Yjs doc stores them (XmlText format ops). */
+function markedText(s: string, marks: Record<string, unknown>): Y.XmlText {
+  const t = new Y.XmlText();
+  t.insert(0, s, marks);
+  return t;
+}
+
+/**
+ * One byte-identical RICH unit: a paragraph with a LINK, a top-level IMAGE, and
+ * a paragraph with a HIGHLIGHT. `live` toggles exactly what the editor
+ * materializes but a git round-trip does not: block `id`, `indent: 0`,
+ * `image.align: "center"`, the link mark's `internal: false`, and the
+ * highlight's `colorName: null`.
+ */
+function richUnit(live: boolean, n: number): Y.XmlElement[] {
+  const ind: Attrs = live ? { indent: 0 } : {};
+  const id = (base: string): Attrs => (live ? { id: `${base}${n}` } : {});
+
+  const linkMarks = live
+    ? {
+        link: {
+          href: 'https://example.com',
+          target: '_blank',
+          rel: 'noopener noreferrer nofollow',
+          class: null,
+          title: null,
+          internal: false, // editor-ext default, materialized
+        },
+      }
+    : {
+        link: {
+          href: 'https://example.com',
+          target: '_blank',
+          rel: 'noopener noreferrer nofollow',
+          internal: null, // engine default
+        },
+      };
+
+  const hlMarks = live
+    ? { highlight: { color: '#ffd43b', colorName: null } }
+    : { highlight: { color: '#ffd43b' } };
+
+  const imageAttrs: Attrs = live
+    ? { src: 'https://img.example.com/a.png', align: 'center' } // materialized
+    : { src: 'https://img.example.com/a.png' }; // align:null dropped on git side
+
+  return [
+    el('paragraph', { ...id('lp'), ...ind }, [
+      markedText('click here', linkMarks),
+    ]),
+    el('image', imageAttrs, []),
+    el('paragraph', { ...id('hp'), ...ind }, [markedText('hot', hlMarks)]),
+  ];
+}
+
+function fragmentOf(units: Y.XmlElement[][]): {
+  doc: Y.Doc;
+  frag: Y.XmlFragment;
+} {
+  const doc = new Y.Doc();
+  const frag = doc.getXmlFragment('default');
+  const blocks = units.flat();
+  if (blocks.length) frag.insert(0, blocks);
+  return { doc, frag };
+}
+
+const blockCount = (frag: Y.XmlFragment): number => frag.toArray().length;
+
+describe('git-sync reconcile is idempotent for schema-default attrs (image/link/highlight)', () => {
+  const UNITS = 3;
+
+  it('3-way: live carries image.align/link.internal/indent defaults, base stale-by-one -> 0 ops', () => {
+    const { doc: liveDoc, frag: live } = fragmentOf(
+      Array.from({ length: UNITS }, (_, i) => richUnit(true, i)),
+    );
+    const { frag: incoming } = fragmentOf(
+      Array.from({ length: UNITS }, (_, i) => richUnit(false, i)),
+    );
+    const { frag: base } = fragmentOf(
+      Array.from({ length: UNITS - 1 }, (_, i) => richUnit(false, i)),
+    );
+
+    const before = blockCount(live);
+    let applied = -1;
+    liveDoc.transact(() => {
+      applied = mergeXmlFragments3Way(live, incoming, base);
+    });
+
+    expect(applied).toBe(0);
+    expect(blockCount(live)).toBe(before);
+  });
+
+  it('2-way: live carries the materialized defaults -> 0 ops, no growth', () => {
+    const { doc: liveDoc, frag: live } = fragmentOf(
+      Array.from({ length: UNITS }, (_, i) => richUnit(true, i)),
+    );
+    const { frag: incoming } = fragmentOf(
+      Array.from({ length: UNITS }, (_, i) => richUnit(false, i)),
+    );
+
+    const before = blockCount(live);
+    let applied = -1;
+    liveDoc.transact(() => {
+      applied = mergeXmlFragments(live, incoming);
+    });
+
+    expect(applied).toBe(0);
+    expect(blockCount(live)).toBe(before);
+  });
+
+  it('is a fixpoint across repeated cycles (does not grow)', () => {
+    const { doc: liveDoc, frag: live } = fragmentOf(
+      Array.from({ length: UNITS }, (_, i) => richUnit(true, i)),
+    );
+    const incoming = () =>
+      fragmentOf(Array.from({ length: UNITS }, (_, i) => richUnit(false, i)))
+        .frag;
+    const base = () =>
+      fragmentOf(
+        Array.from({ length: UNITS - 1 }, (_, i) => richUnit(false, i)),
+      ).frag;
+
+    const before = blockCount(live);
+    for (let cycle = 0; cycle < 5; cycle++) {
+      let applied = -1;
+      liveDoc.transact(() => {
+        applied = mergeXmlFragments3Way(live, incoming(), base());
+      });
+      expect(applied).toBe(0);
+      expect(blockCount(live)).toBe(before);
+    }
+  });
+
+  it('does NOT regress a genuine non-default value (a real link.href / image.align:left still diffs)', () => {
+    const { doc: liveDoc, frag: live } = fragmentOf([richUnit(true, 0)]);
+    const base = fragmentOf([richUnit(false, 0)]).frag;
+    // git genuinely changes the image alignment to a NON-default value.
+    const incomingUnit = richUnit(false, 0);
+    (incomingUnit[1] as Y.XmlElement).setAttribute('align', 'left');
+    const incoming = fragmentOf([incomingUnit]).frag;
+
+    liveDoc.transact(() => {
+      mergeXmlFragments3Way(live, incoming, base);
+    });
+
+    const img = live
+      .toArray()
+      .find((b) => (b as Y.XmlElement).nodeName === 'image') as Y.XmlElement;
+    expect(img.getAttribute('align')).toBe('left');
+  });
+});
+
+/**
+ * FAITHFUL end-to-end proof through the REAL server transformer: build the live
+ * doc the way the collaboration server does (defaults omitted in the JSON ->
+ * TiptapTransformer.toYdoc MATERIALIZES image.align:"center", link.internal:false,
+ * indent:0) versus the git-derived doc (engine-style: defaults emitted as
+ * explicit null, no block ids). An unchanged resync must apply 0 ops.
+ */
+describe('git-sync reconcile is idempotent through the real toYdoc materialization', () => {
+  const liveContent = [
+    {
+      type: 'paragraph',
+      attrs: { id: 'p1' },
+      content: [
+        {
+          type: 'text',
+          text: 'click here',
+          marks: [{ type: 'link', attrs: { href: 'https://example.com' } }],
+        },
+      ],
+    },
+    { type: 'image', attrs: { src: 'https://img.example.com/a.png' } },
+    {
+      type: 'paragraph',
+      attrs: { id: 'p2' },
+      content: [
+        {
+          type: 'text',
+          text: 'hot',
+          marks: [{ type: 'highlight', attrs: { color: '#ffd43b' } }],
+        },
+      ],
+    },
+  ];
+
+  // git/engine-style: explicit nulls for the engine-default attrs, no ids.
+  const gitContent = [
+    {
+      type: 'paragraph',
+      content: [
+        {
+          type: 'text',
+          text: 'click here',
+          marks: [
+            {
+              type: 'link',
+              attrs: {
+                href: 'https://example.com',
+                target: '_blank',
+                rel: 'noopener noreferrer nofollow',
+                class: null,
+                title: null,
+                internal: null,
+              },
+            },
+          ],
+        },
+      ],
+    },
+    {
+      type: 'image',
+      attrs: { src: 'https://img.example.com/a.png', align: null },
+    },
+    {
+      type: 'paragraph',
+      content: [
+        {
+          type: 'text',
+          text: 'hot',
+          marks: [
+            { type: 'highlight', attrs: { color: '#ffd43b', colorName: null } },
+          ],
+        },
+      ],
+    },
+  ];
+
+  const toYdoc = (content: unknown[]) =>
+    TiptapTransformer.toYdoc(
+      { type: 'doc', content },
+      'default',
+      tiptapExtensions as any,
+    );
+
+  it('3-way: materialized-default live vs engine-style git, base stale-by-one -> 0 ops', () => {
+    const liveDoc = toYdoc(liveContent);
+    const targetDoc = toYdoc(gitContent);
+    const baseDoc = toYdoc(gitContent.slice(0, gitContent.length - 1));
+
+    const live = liveDoc.getXmlFragment('default');
+    const before = live.toArray().length;
+    let applied = -1;
+    liveDoc.transact(() => {
+      applied = mergeXmlFragments3Way(
+        live,
+        targetDoc.getXmlFragment('default'),
+        baseDoc.getXmlFragment('default'),
+      );
+    });
+
+    expect(applied).toBe(0);
+    expect(live.toArray().length).toBe(before);
+  });
+
+  it('2-way: materialized-default live vs engine-style git -> 0 ops', () => {
+    const liveDoc = toYdoc(liveContent);
+    const targetDoc = toYdoc(gitContent);
+
+    const live = liveDoc.getXmlFragment('default');
+    const before = live.toArray().length;
+    let applied = -1;
+    liveDoc.transact(() => {
+      applied = mergeXmlFragments(live, targetDoc.getXmlFragment('default'));
+    });
+
+    expect(applied).toBe(0);
+    expect(live.toArray().length).toBe(before);
+  });
+});

apps/server/src/collaboration/merge/yjs-body-merge.spec.ts

@@ -0,0 +1,373 @@
+import * as Y from 'yjs';
+
+import {
+  mergeXmlFragments,
+  mergeXmlFragments3Way,
+  mergeXmlFragments3WayWithStats,
+  cloneXmlNode,
+  diffBlocks,
+} from './yjs-body-merge';
+
+// Build a Y.XmlFragment('default') in `doc` from a list of paragraph specs.
+// Each spec is the paragraph's plain text (a single XmlText child).
+function buildFragment(doc: Y.Doc, paragraphs: string[]): Y.XmlFragment {
+  const frag = doc.getXmlFragment('default');
+  const blocks = paragraphs.map((text) => {
+    const el = new Y.XmlElement('paragraph');
+    const t = new Y.XmlText();
+    if (text) t.insert(0, text);
+    el.insert(0, [t]);
+    return el;
+  });
+  if (blocks.length) frag.insert(0, blocks);
+  return frag;
+}
+
+function texts(frag: Y.XmlFragment): string[] {
+  return frag.toArray().map((el) => (el as Y.XmlElement).toArray()
+    .map((c) => (c as Y.XmlText).toString())
+    .join(''));
+}
+
+describe('yjs-body-merge', () => {
+  describe('diffBlocks (LCS edit script)', () => {
+    it('identical sequences produce only keeps (no edits)', () => {
+      const ops = diffBlocks(['a', 'b', 'c'], ['a', 'b', 'c']);
+      expect(ops.every((o) => o.op === 'keep')).toBe(true);
+    });
+
+    it('a single changed middle element is one del + one ins', () => {
+      const ops = diffBlocks(['a', 'b', 'c'], ['a', 'B', 'c']);
+      expect(ops.filter((o) => o.op === 'del')).toHaveLength(1);
+      expect(ops.filter((o) => o.op === 'ins')).toHaveLength(1);
+      expect(ops.filter((o) => o.op === 'keep')).toHaveLength(2);
+    });
+  });
+
+  describe('mergeXmlFragments', () => {
+    it('identical content is a complete no-op (0 ops) — never clobbers an unchanged resync', () => {
+      const live = new Y.Doc();
+      const target = new Y.Doc();
+      const liveFrag = buildFragment(live, ['one', 'two', 'three']);
+      const targetFrag = buildFragment(target, ['one', 'two', 'three']);
+
+      // Capture block identities to prove they are left untouched.
+      const before = liveFrag.toArray();
+      let applied = -1;
+      live.transact(() => {
+        applied = mergeXmlFragments(liveFrag, targetFrag);
+      });
+
+      expect(applied).toBe(0);
+      // Same Y.XmlElement instances — nothing was deleted/recreated.
+      expect(liveFrag.toArray()).toEqual(before);
+      expect(texts(liveFrag)).toEqual(['one', 'two', 'three']);
+    });
+
+    it('a human edit to one block survives a git change to a DIFFERENT block', () => {
+      // Live: the human has the doc open; block 0 holds their edit. Git changed
+      // only block 2. The merge must touch ONLY block 2 and leave block 0 (and
+      // its in-flight edit) exactly as-is.
+      const live = new Y.Doc();
+      const target = new Y.Doc();
+      const liveFrag = buildFragment(live, ['HUMAN EDIT', 'shared', 'old tail']);
+      const targetFrag = buildFragment(target, [
+        'HUMAN EDIT',
+        'shared',
+        'new tail from git',
+      ]);
+
+      const block0Before = liveFrag.get(0); // the human's block instance
+      const block1Before = liveFrag.get(1);
+
+      let applied = -1;
+      live.transact(() => {
+        applied = mergeXmlFragments(liveFrag, targetFrag);
+      });
+
+      // Only block 2 was replaced: one del + one ins.
+      expect(applied).toBe(2);
+      // The human's block and the shared block are the SAME instances (untouched).
+      expect(liveFrag.get(0)).toBe(block0Before);
+      expect(liveFrag.get(1)).toBe(block1Before);
+      // Block 2 now carries git's content.
+      expect(texts(liveFrag)).toEqual([
+        'HUMAN EDIT',
+        'shared',
+        'new tail from git',
+      ]);
+    });
+
+    it('appends a new trailing block without disturbing existing ones', () => {
+      const live = new Y.Doc();
+      const target = new Y.Doc();
+      const liveFrag = buildFragment(live, ['a', 'b']);
+      const targetFrag = buildFragment(target, ['a', 'b', 'c']);
+      const a = liveFrag.get(0);
+      const b = liveFrag.get(1);
+
+      let applied = -1;
+      live.transact(() => {
+        applied = mergeXmlFragments(liveFrag, targetFrag);
+      });
+
+      expect(applied).toBe(1); // single insert
+      expect(liveFrag.get(0)).toBe(a);
+      expect(liveFrag.get(1)).toBe(b);
+      expect(texts(liveFrag)).toEqual(['a', 'b', 'c']);
+    });
+
+    it('deletes a removed block, keeping its neighbours', () => {
+      const live = new Y.Doc();
+      const target = new Y.Doc();
+      const liveFrag = buildFragment(live, ['a', 'b', 'c']);
+      const targetFrag = buildFragment(target, ['a', 'c']);
+      const a = liveFrag.get(0);
+
+      let applied = -1;
+      live.transact(() => {
+        applied = mergeXmlFragments(liveFrag, targetFrag);
+      });
+
+      expect(applied).toBe(1); // single delete
+      expect(liveFrag.get(0)).toBe(a);
+      expect(texts(liveFrag)).toEqual(['a', 'c']);
+    });
+
+    it('a fully different body is replaced (and stays valid)', () => {
+      const live = new Y.Doc();
+      const target = new Y.Doc();
+      const liveFrag = buildFragment(live, ['x', 'y']);
+      const targetFrag = buildFragment(target, ['p', 'q', 'r']);
+      live.transact(() => mergeXmlFragments(liveFrag, targetFrag));
+      expect(texts(liveFrag)).toEqual(['p', 'q', 'r']);
+    });
+  });
+
+  describe('mergeXmlFragments3Way', () => {
+    it('keeps a human edit to one block while applying a git change to another (3-way)', () => {
+      // base (last synced): [a, b, c]. Human edited block 0 in the live doc; git
+      // changed block 2 in the incoming file. 3-way must keep BOTH — the 2-way
+      // merge would instead revert the human's block 0 to git's stale version.
+      const base = new Y.Doc();
+      const live = new Y.Doc();
+      const target = new Y.Doc();
+      const baseFrag = buildFragment(base, ['a', 'b', 'c']);
+      const liveFrag = buildFragment(live, ['HUMAN', 'b', 'c']);
+      const targetFrag = buildFragment(target, ['a', 'b', 'GIT']);
+
+      const humanBlock = liveFrag.get(0); // the human's live instance
+      live.transact(() =>
+        mergeXmlFragments3Way(liveFrag, targetFrag, baseFrag),
+      );
+
+      // Human's block preserved as the SAME instance; git's change applied.
+      expect(liveFrag.get(0)).toBe(humanBlock);
+      expect(texts(liveFrag)).toEqual(['HUMAN', 'b', 'GIT']);
+    });
+
+    it('a block both sides changed resolves to git (conflict policy)', () => {
+      const base = new Y.Doc();
+      const live = new Y.Doc();
+      const target = new Y.Doc();
+      const baseFrag = buildFragment(base, ['a', 'b', 'c']);
+      const liveFrag = buildFragment(live, ['a', 'HUMAN', 'c']);
+      const targetFrag = buildFragment(target, ['a', 'GIT', 'c']);
+
+      live.transact(() =>
+        mergeXmlFragments3Way(liveFrag, targetFrag, baseFrag),
+      );
+      expect(texts(liveFrag)).toEqual(['a', 'GIT', 'c']);
+    });
+
+    // Bug #2 observability: the stats variant reports the same-block conflict so
+    // the handler can log it + the persistence layer can pin the human baseline.
+    it('reports the same-block conflict count via mergeXmlFragments3WayWithStats', () => {
+      const base = new Y.Doc();
+      const live = new Y.Doc();
+      const target = new Y.Doc();
+      const baseFrag = buildFragment(base, ['a', 'b', 'c']);
+      const liveFrag = buildFragment(live, ['a', 'HUMAN', 'c']);
+      const targetFrag = buildFragment(target, ['a', 'GIT', 'c']);
+
+      let result!: { applied: number; conflicts: number };
+      live.transact(() => {
+        result = mergeXmlFragments3WayWithStats(liveFrag, targetFrag, baseFrag);
+      });
+      expect(result.conflicts).toBe(1);
+      expect(texts(liveFrag)).toEqual(['a', 'GIT', 'c']);
+    });
+
+    it('reports 0 conflicts for a clean different-block 3-way merge', () => {
+      const base = new Y.Doc();
+      const live = new Y.Doc();
+      const target = new Y.Doc();
+      const baseFrag = buildFragment(base, ['a', 'b', 'c']);
+      const liveFrag = buildFragment(live, ['HUMAN', 'b', 'c']);
+      const targetFrag = buildFragment(target, ['a', 'b', 'GIT']);
+
+      let result!: { applied: number; conflicts: number };
+      live.transact(() => {
+        result = mergeXmlFragments3WayWithStats(liveFrag, targetFrag, baseFrag);
+      });
+      expect(result.conflicts).toBe(0);
+      expect(texts(liveFrag)).toEqual(['HUMAN', 'b', 'GIT']);
+    });
+
+    it('git change with no concurrent human edit (live == base) applies cleanly', () => {
+      const base = new Y.Doc();
+      const live = new Y.Doc();
+      const target = new Y.Doc();
+      const baseFrag = buildFragment(base, ['a', 'b']);
+      const liveFrag = buildFragment(live, ['a', 'b']);
+      const targetFrag = buildFragment(target, ['a', 'B2']);
+
+      live.transact(() =>
+        mergeXmlFragments3Way(liveFrag, targetFrag, baseFrag),
+      );
+      expect(texts(liveFrag)).toEqual(['a', 'B2']);
+    });
+  });
+
+  // Regression: start-of-document content duplicating on every two-way sync.
+  //
+  // The LIVE Docmost doc stamps a per-block UniqueID on every heading/paragraph;
+  // a body arriving FROM git is parsed from clean markdown and carries NO block
+  // ids. If the merge comparison key includes that `id`, an unchanged live block
+  // never matches the SAME block coming from git, so the three-way merge cannot
+  // anchor on it — and an incoming block with no anchor (content inserted at the
+  // TOP of the page) is RE-ADDED on every cycle, an unbounded duplication loop.
+  // These tests model that exact id-asymmetry and assert the reconciliation is
+  // IDEMPOTENT (no block growth). They are RED before excluding `id` from the
+  // key in `serializeXmlNode`.
+  describe('idempotent reconciliation with live block ids (start-of-doc dup)', () => {
+    // Build a fragment from block specs. `id` is set only when provided, mirroring
+    // the live doc (ids present) vs a git-parsed body (ids absent).
+    type Spec = { tag: 'heading' | 'paragraph'; text: string; id?: string };
+    function buildDoc(doc: Y.Doc, specs: Spec[]): Y.XmlFragment {
+      const frag = doc.getXmlFragment('default');
+      const blocks = specs.map((s) => {
+        const el = new Y.XmlElement(s.tag);
+        if (s.id) el.setAttribute('id', s.id);
+        if (s.tag === 'heading') el.setAttribute('level', '2');
+        const t = new Y.XmlText();
+        if (s.text) t.insert(0, s.text);
+        el.insert(0, [t]);
+        return el;
+      });
+      if (blocks.length) frag.insert(0, blocks);
+      return frag;
+    }
+    const textsOf = (frag: Y.XmlFragment): string[] =>
+      frag.toArray().map((el) =>
+        (el as Y.XmlElement)
+          .toArray()
+          .map((c) => (c as Y.XmlText).toString())
+          .join(''),
+      );
+
+    it('re-merging the SAME git body does NOT re-add the top block (idempotent)', () => {
+      // last-synced base (from git markdown): NO block ids.
+      const base = new Y.Doc();
+      const baseFrag = buildDoc(base, [
+        { tag: 'heading', text: 'Title' },
+        { tag: 'paragraph', text: 'Some paragraph.' },
+        { tag: 'paragraph', text: 'End block.' },
+      ]);
+      // live Docmost doc: SAME content, but every block carries a UniqueID.
+      const live = new Y.Doc();
+      const liveFrag = buildDoc(live, [
+        { tag: 'heading', text: 'Title', id: 'ida' },
+        { tag: 'paragraph', text: 'Some paragraph.', id: 'idb' },
+        { tag: 'paragraph', text: 'End block.', id: 'idc' },
+      ]);
+      // incoming git body: the user inserted a heading at the very TOP.
+      const buildTarget = (): Y.XmlFragment =>
+        buildDoc(new Y.Doc(), [
+          { tag: 'heading', text: 'TOPDUP' },
+          { tag: 'heading', text: 'Title' },
+          { tag: 'paragraph', text: 'Some paragraph.' },
+          { tag: 'paragraph', text: 'End block.' },
+        ]);
+
+      // First sync: the top block is added once.
+      live.transact(() =>
+        mergeXmlFragments3Way(liveFrag, buildTarget(), baseFrag),
+      );
+      expect(textsOf(liveFrag)).toEqual([
+        'TOPDUP',
+        'Title',
+        'Some paragraph.',
+        'End block.',
+      ]);
+
+      // Subsequent sync of the SAME git body against the SAME base must be a
+      // NO-OP — not a second copy of the top block. Before the fix this re-adds
+      // 'TOPDUP', growing the doc on every cycle.
+      live.transact(() =>
+        mergeXmlFragments3Way(liveFrag, buildTarget(), baseFrag),
+      );
+      expect(textsOf(liveFrag)).toEqual([
+        'TOPDUP',
+        'Title',
+        'Some paragraph.',
+        'End block.',
+      ]);
+      expect(textsOf(liveFrag).filter((t) => t === 'TOPDUP')).toHaveLength(1);
+    });
+
+    it('an unchanged git body (live ids, none in git) is a complete no-op', () => {
+      // base == git body (no pending git change); live is the same content with
+      // ids. With `id` in the key the whole body looks rewritten; the merge must
+      // still leave live byte-identical (block instances untouched).
+      const base = new Y.Doc();
+      const baseFrag = buildDoc(base, [
+        { tag: 'heading', text: 'Title' },
+        { tag: 'paragraph', text: 'Body.' },
+      ]);
+      const live = new Y.Doc();
+      const liveFrag = buildDoc(live, [
+        { tag: 'heading', text: 'Title', id: 'ida' },
+        { tag: 'paragraph', text: 'Body.', id: 'idb' },
+      ]);
+      const before = liveFrag.toArray();
+      let applied = -1;
+      live.transact(() => {
+        applied = mergeXmlFragments3Way(
+          liveFrag,
+          buildDoc(new Y.Doc(), [
+            { tag: 'heading', text: 'Title' },
+            { tag: 'paragraph', text: 'Body.' },
+          ]),
+          baseFrag,
+        );
+      });
+      expect(applied).toBe(0);
+      // Same live block instances (ids preserved) — nothing recreated.
+      expect(liveFrag.toArray()).toEqual(before);
+    });
+  });
+
+  describe('cloneXmlNode', () => {
+    it('preserves text marks (XmlText delta) across docs', () => {
+      const src = new Y.Doc();
+      const srcFrag = src.getXmlFragment('default');
+      const el = new Y.XmlElement('paragraph');
+      const t = new Y.XmlText();
+      t.insert(0, 'plain ');
+      t.insert(6, 'bold', { bold: true });
+      el.insert(0, [t]);
+      srcFrag.insert(0, [el]);
+
+      const dst = new Y.Doc();
+      const dstFrag = dst.getXmlFragment('default');
+      dstFrag.insert(0, [cloneXmlNode(srcFrag.get(0) as Y.XmlElement)]);
+
+      const clonedText = (dstFrag.get(0) as Y.XmlElement).get(0) as Y.XmlText;
+      expect(clonedText.toDelta()).toEqual([
+        { insert: 'plain ' },
+        { insert: 'bold', attributes: { bold: true } },
+      ]);
+    });
+  });
+});

apps/server/src/collaboration/merge/yjs-body-merge.ts

@@ -0,0 +1,369 @@
+import * as Y from 'yjs';
+import { getSchema } from '@tiptap/core';
+import type { Schema } from '@tiptap/pm/model';
+
+import { tiptapExtensions } from '../collaboration.util';
+import { diff3PlanWithConflicts } from './three-way-merge';
+import { buildLcsTable } from './lcs';
+
+/**
+ * Block-level merge of an incoming (git) page body into a LIVE Yjs document,
+ * replacing the previous full-body "delete everything + re-insert" write that
+ * clobbered concurrent human edits on every sync (review #5 — "do the write as a
+ * merge").
+ *
+ * Strategy: diff the two documents at TOP-LEVEL BLOCK granularity (an LCS over a
+ * canonical structural serialization of each block) and apply only the minimal
+ * insert/delete operations. Blocks that are byte-identical on both sides are
+ * left UNTOUCHED in the live doc — so a human editing one paragraph is unaffected
+ * when git changes a different paragraph, and an unchanged re-sync is a complete
+ * no-op (zero Yjs operations). Yjs then CRDT-merges the minimal ops with any
+ * concurrent edits.
+ *
+ * Limitation (honest): this is a 2-way merge (live vs incoming). For a block that
+ * BOTH sides changed since the last sync it cannot tell which is newer without a
+ * common ancestor, so the incoming (git) version wins for that one block. A full
+ * 3-way merge would need the last-synced base plumbed from the engine; the common
+ * cases — unchanged resync, and edits to DIFFERENT blocks — are handled losslessly.
+ */
+
+type XmlNode = Y.XmlElement | Y.XmlText | Y.XmlHook;
+
+/**
+ * Node attributes that are VOLATILE identity (not content) and so must be
+ * excluded from the block comparison key.
+ *
+ * `id` is the per-block UniqueID the editor stamps on every heading/paragraph
+ * (and transclusionSource). It exists ONLY in the live Yjs document — a body
+ * arriving from git is parsed from clean markdown, which carries no block ids
+ * (`markdownToProseMirror` materializes `id: null`, which the Yjs transform then
+ * drops). If `id` were part of the key, an UNCHANGED live block (id "abc123")
+ * would never match the SAME block coming from git (no id), so the three-way
+ * merge's LCS could not anchor on it. The merge would then treat every live
+ * block as deleted-and-reinserted and, when an incoming block has no matching
+ * anchor (e.g. content inserted at the very TOP of the page), RE-ADD a copy of
+ * it on every sync cycle — a non-convergent, unbounded duplication loop
+ * (start-of-document content duplicating each push/pull cycle).
+ *
+ * Excluding `id` makes blocks compare by CONTENT, so an unchanged block matches
+ * across the git round-trip and the reconciliation is idempotent. Block identity
+ * is still preserved in the merged output: `diff3Plan` keeps the LIVE block
+ * INSTANCE (with its id) for an anchor — picks are by index, not by key — so the
+ * stable Yjs block (and any in-flight human edit on it) stays put. This mirrors
+ * `canonicalize.ts`, which already strips the regenerated block `id` from the
+ * round-trip idempotency comparison for exactly the same reason.
+ *
+ * Known limitation (accepted trade-off of content-based matching): two GENUINELY
+ * DISTINCT blocks whose content is byte-identical now collapse to the same content
+ * key, so when git deletes one of the duplicates the LCS may drop the OTHER live
+ * instance instead. The visible result is identical (one copy removed, one kept),
+ * but a concurrent in-flight human edit on the dropped instance could be lost.
+ */
+const VOLATILE_KEY_ATTRS = new Set(['id']);
+
+/**
+ * The editor (ProseMirror) schema, built ONCE from the same `tiptapExtensions`
+ * the collaboration server uses to materialize Yjs docs. Memoized: building the
+ * schema is non-trivial and the block key is computed per block per cycle.
+ *
+ * Why the schema (not a hardcoded denylist): the LIVE Yjs document is produced by
+ * `TiptapTransformer.toYdoc(pm, 'default', tiptapExtensions)`, which STAMPS every
+ * schema-default attribute onto every node and mark — `indent: 0` on every
+ * paragraph/heading, `image.align: "center"`, the link mark's `internal: false`,
+ * `highlight.colorName: null`, and so on for youtube/pdf/any future node. A body
+ * re-imported from git comes through the engine's `markdownToProseMirror`, whose
+ * schema declares those attrs with DIFFERENT (usually null) defaults; the
+ * resulting null/absent element attrs are then DROPPED by `y-prosemirror`'s
+ * toYdoc. So the SAME block carries materialized defaults on the live side and
+ * nothing on the git side, its key diverges, the three-way merge anchors on
+ * NOTHING, and the whole body is RE-APPENDED every reconcile cycle — an unbounded
+ * duplication loop with no client connected.
+ *
+ * Deriving the defaults from the actual schema normalizes ALL such attributes
+ * generally (it is not another per-attribute denylist): any attribute whose value
+ * equals the schema default — or is null/undefined — is dropped from the key, on
+ * BOTH element attributes and the mark attributes inside each XmlText delta, so a
+ * live block compares equal to its git-round-tripped twin and an unchanged resync
+ * applies zero ops. Genuinely non-default values (a real `indent: 2`, an
+ * `align: "left"`, a real `link.href`, a real highlight color) are content and
+ * stay in the key, so real edits still diff and land.
+ */
+let memoSchema: Schema | null = null;
+let memoSchemaTried = false;
+function getMergeSchema(): Schema | null {
+  if (!memoSchemaTried) {
+    memoSchemaTried = true;
+    try {
+      memoSchema = getSchema(tiptapExtensions as any);
+    } catch {
+      // Defensive: if the schema can't be built (e.g. a degenerate extension
+      // set in a unit test that stubs `tiptapExtensions`), fall back to dropping
+      // only null/undefined attrs. The real server always builds it fine.
+      memoSchema = null;
+    }
+  }
+  return memoSchema;
+}
+
+/** True if `value` is the schema default for `attrName` of `attrSpecs`, or is
+ * null/undefined (which a git round-trip drops). Such attributes are excluded
+ * from the comparison key. `attrSpecs` is a ProseMirror node/mark spec attr map
+ * (`{ [name]: { default } }`); a missing map (unknown node/mark) only drops
+ * null/undefined. (A non-null value matching an attr declared without a default
+ * cannot occur — `spec.default === value` is then `undefined === value`, false.) */
+function isDefaultAttr(
+  attrSpecs: Record<string, any> | undefined | null,
+  attrName: string,
+  value: unknown,
+): boolean {
+  if (value === null || value === undefined) return true;
+  const spec = attrSpecs?.[attrName];
+  return !!spec && spec.default === value;
+}
+
+/**
+ * Normalize one XmlText delta op's mark attributes: drop every mark-attr whose
+ * value equals the mark's schema default (or is null/undefined), so the link
+ * mark's materialized `internal: false`/`target: "_blank"` and a highlight's
+ * `colorName: null` no longer diverge from a git round-trip that carries neither.
+ * The text (op.insert) and genuinely-set mark attrs (a real `href`, a real
+ * highlight color) are preserved verbatim. `attributes` maps markName -> mark
+ * attrs object (or `true`/boolean for attr-less marks); each is handled safely.
+ */
+function normalizeDelta(delta: any[]): any[] {
+  const schema = getMergeSchema();
+  return delta.map((op) => {
+    if (!op || op.attributes == null || typeof op.attributes !== 'object') {
+      return op;
+    }
+    const marks: Record<string, unknown> = {};
+    for (const markName of Object.keys(op.attributes).sort()) {
+      const markVal = op.attributes[markName];
+      if (markVal === null || markVal === undefined) continue;
+      if (typeof markVal !== 'object') {
+        // attr-less mark stored as a primitive (e.g. `true`) — keep as-is.
+        marks[markName] = markVal;
+        continue;
+      }
+      const markSpec = schema?.marks[markName]?.spec.attrs as
+        | Record<string, any>
+        | undefined;
+      const cleaned: Record<string, unknown> = {};
+      for (const ak of Object.keys(markVal as object).sort()) {
+        const av = (markVal as Record<string, unknown>)[ak];
+        if (isDefaultAttr(markSpec, ak, av)) continue;
+        cleaned[ak] = av;
+      }
+      marks[markName] = cleaned;
+    }
+    return { ...op, attributes: marks };
+  });
+}
+
+/**
+ * Canonical, comparable serialization of a Yjs XML node (structure + text +
+ * marks + attributes), with attribute keys sorted so equal blocks always produce
+ * an identical string regardless of attribute insertion order. The volatile
+ * block `id` (see `VOLATILE_KEY_ATTRS`) and every schema-default attribute (see
+ * `getMergeSchema`) are excluded at every level — on element attributes AND on
+ * the mark attributes inside each XmlText delta — so a block compares equal by
+ * CONTENT across the git round-trip (which materializes neither), keeping the
+ * merge anchor-able and idempotent.
+ */
+export function serializeXmlNode(node: unknown): unknown {
+  if (node instanceof Y.XmlText) {
+    return { t: normalizeDelta(node.toDelta()) };
+  }
+  if (node instanceof Y.XmlElement) {
+    const attrs = node.getAttributes() as Record<string, unknown>;
+    const attrSpecs = getMergeSchema()?.nodes[node.nodeName]?.spec.attrs as
+      | Record<string, any>
+      | undefined;
+    const sorted: Record<string, unknown> = {};
+    for (const k of Object.keys(attrs).sort()) {
+      if (VOLATILE_KEY_ATTRS.has(k)) continue;
+      if (isDefaultAttr(attrSpecs, k, attrs[k])) continue;
+      sorted[k] = attrs[k];
+    }
+    return {
+      n: node.nodeName,
+      a: sorted,
+      c: node.toArray().map(serializeXmlNode),
+    };
+  }
+  // XmlHook / unknown: fall back to a stable string so it compares by identity
+  // of its serialized form (these do not occur in the Docmost block schema).
+  return { u: String(node) };
+}
+
+const key = (node: unknown): string => JSON.stringify(serializeXmlNode(node));
+
+/**
+ * Deep-clone a detached/owned Yjs XML node into a fresh node that can be inserted
+ * into ANOTHER document (Yjs types are bound to their doc, so cross-doc moves are
+ * impossible — we rebuild). Preserves nodeName, attributes, text+marks (via the
+ * XmlText delta) and the full child subtree.
+ */
+export function cloneXmlNode(node: XmlNode): Y.XmlElement | Y.XmlText {
+  if (node instanceof Y.XmlText) {
+    const t = new Y.XmlText();
+    const delta = node.toDelta();
+    if (delta.length) t.applyDelta(delta);
+    return t;
+  }
+  if (node instanceof Y.XmlElement) {
+    const el = new Y.XmlElement(node.nodeName);
+    const attrs = node.getAttributes() as Record<string, unknown>;
+    for (const k of Object.keys(attrs)) el.setAttribute(k, attrs[k] as string);
+    const kids = node.toArray().map((c) => cloneXmlNode(c as XmlNode));
+    if (kids.length) el.insert(0, kids);
+    return el;
+  }
+  // Best-effort for any other node type (XmlHook — does not occur in the
+  // Docmost block schema): an empty paragraph so the merge never crashes.
+  return new Y.XmlElement('paragraph');
+}
+
+type Op = { op: 'keep' } | { op: 'del' } | { op: 'ins'; bi: number };
+
+/**
+ * LCS-based edit script turning sequence `a` (live block keys) into `b` (incoming
+ * block keys): a run of keep/del/ins ops. O(n*m) table — fine for page block
+ * counts.
+ */
+export function diffBlocks(a: string[], b: string[]): Op[] {
+  const n = a.length;
+  const m = b.length;
+  const dp = buildLcsTable(a, b);
+  const ops: Op[] = [];
+  let i = 0;
+  let j = 0;
+  while (i < n && j < m) {
+    if (a[i] === b[j]) {
+      ops.push({ op: 'keep' });
+      i++;
+      j++;
+    } else if (dp[i + 1][j] >= dp[i][j + 1]) {
+      ops.push({ op: 'del' });
+      i++;
+    } else {
+      ops.push({ op: 'ins', bi: j });
+      j++;
+    }
+  }
+  while (i < n) {
+    ops.push({ op: 'del' });
+    i++;
+  }
+  while (j < m) {
+    ops.push({ op: 'ins', bi: j });
+    j++;
+  }
+  return ops;
+}
+
+/**
+ * Merge `target` block children into `live`, mutating `live` in place with the
+ * minimal set of inserts/deletes. MUST be called inside a Yjs transaction.
+ * Returns the number of block operations applied (0 == content already identical).
+ */
+export function mergeXmlFragments(
+  live: Y.XmlFragment,
+  target: Y.XmlFragment,
+): number {
+  const liveKids = live.toArray();
+  const targetKids = target.toArray();
+  const liveKeys = liveKids.map(key);
+  const targetKeys = targetKids.map(key);
+
+  const ops = diffBlocks(liveKeys, targetKeys);
+
+  let cursor = 0; // index into the LIVE fragment as we mutate it
+  let applied = 0;
+  for (const op of ops) {
+    if (op.op === 'keep') {
+      cursor++;
+    } else if (op.op === 'del') {
+      live.delete(cursor, 1); // remove the live block at the cursor; do not advance
+      applied++;
+    } else {
+      live.insert(cursor, [cloneXmlNode(targetKids[op.bi] as XmlNode)]);
+      cursor++;
+      applied++;
+    }
+  }
+  return applied;
+}
+
+/** Outcome of a 3-way block merge: ops applied + same-block conflict count. */
+export interface Merge3WayResult {
+  /** Number of block insert/delete operations spliced into `live`. */
+  applied: number;
+  /**
+   * Regions where the human AND git rewrote the SAME base block. The rule is
+   * deterministic (GIT WINS the region), so the human's version of those blocks
+   * is dropped from the live doc. `conflicts > 0` is the OBSERVABLE signal the
+   * caller uses to LOG the loss and pin the human baseline to page history (so it
+   * is recoverable), instead of the edit vanishing silently.
+   */
+  conflicts: number;
+}
+
+/**
+ * THREE-WAY block merge: reconcile `live` toward `target` using `base` (the
+ * last-synced common ancestor) so a block only the human changed is KEPT and a
+ * block only git changed is taken — instead of git's version always winning
+ * (review #5). Conflicts (both changed the same block) resolve to git.
+ *
+ * Implementation: diff3Plan computes the merged block ORDER (picks from live or
+ * target); we materialize that as a virtual target fragment and reuse the 2-way
+ * `mergeXmlFragments` to splice it into `live` minimally (so untouched live block
+ * instances — and their in-flight edits — stay put). MUST be called inside a Yjs
+ * transaction. Returns the number of block operations applied. (Use
+ * `mergeXmlFragments3WayWithStats` when the SAME-BLOCK conflict count is needed.)
+ */
+export function mergeXmlFragments3Way(
+  live: Y.XmlFragment,
+  target: Y.XmlFragment,
+  base: Y.XmlFragment,
+): number {
+  return mergeXmlFragments3WayWithStats(live, target, base).applied;
+}
+
+/**
+ * As `mergeXmlFragments3Way`, but also returns the SAME-BLOCK conflict count so
+ * the caller can make a "git won a concurrent same-block edit" event OBSERVABLE
+ * (the documented conflict contract: git wins deterministically, but the losing
+ * human content is never destroyed silently — it is logged and recoverable via
+ * page history).
+ */
+export function mergeXmlFragments3WayWithStats(
+  live: Y.XmlFragment,
+  target: Y.XmlFragment,
+  base: Y.XmlFragment,
+): Merge3WayResult {
+  const liveKids = live.toArray();
+  const targetKids = target.toArray();
+  const liveKeys = liveKids.map(key);
+  const targetKeys = targetKids.map(key);
+  const baseKeys = base.toArray().map(key);
+
+  const { picks: plan, conflicts } = diff3PlanWithConflicts(
+    baseKeys,
+    liveKeys,
+    targetKeys,
+  );
+
+  // Build the merged block sequence in a throwaway doc, cloning from whichever
+  // side each pick came from, then 2-way merge it back into the live fragment.
+  const merged = new Y.Doc();
+  const mergedFrag = merged.getXmlFragment('default');
+  const nodes = plan.map((p) =>
+    cloneXmlNode(
+      (p.src === 'live' ? liveKids[p.index] : targetKids[p.index]) as XmlNode,
+    ),
+  );
+  if (nodes.length) mergedFrag.insert(0, nodes);
+
+  return { applied: mergeXmlFragments(live, mergedFrag), conflicts };
+}

apps/server/src/common/decorators/auth-provenance.decorator.spec.ts

@@ -73,6 +73,32 @@ describe('agentSourceFields', () => {
     ).toEqual({ lastUpdatedSource: 'agent', lastUpdatedAiChatId: null });
   });
 
+  it("stamps ONLY the source column 'git-sync' (no chat key) for a git-sync write", () => {
+    // The git-sync data plane (issue #194 §8.1) has no internal ai_chats row, so
+    // it stamps the *Source column 'git-sync' and OMITS the chat key entirely
+    // (unlike the agent branch, which also writes aiChatId). Pinned directly here
+    // because the page.service.spec only exercises it indirectly.
+    expect(
+      agentSourceFields(
+        { actor: 'git-sync', aiChatId: null },
+        'lastUpdatedSource',
+        'lastUpdatedAiChatId',
+      ),
+    ).toEqual({ lastUpdatedSource: 'git-sync' });
+  });
+
+  it("ignores any aiChatId on a git-sync write (chat key never written)", () => {
+    // Even if a non-null aiChatId is present, the git-sync branch must not emit
+    // the chat key.
+    expect(
+      agentSourceFields(
+        { actor: 'git-sync', aiChatId: 'should-be-ignored' },
+        'createdSource',
+        'aiChatId',
+      ),
+    ).toEqual({ createdSource: 'git-sync' });
+  });
+
   it('returns {} for a user write so the column keeps its default', () => {
     expect(
       agentSourceFields(

apps/server/src/common/decorators/auth-provenance.decorator.ts

@@ -9,6 +9,8 @@ import { ProvenanceSource } from '../../core/auth/dto/jwt-payload';
  * cannot fake an 'agent' marker.
  */
 export interface AuthProvenanceData {
+  // ProvenanceSource includes 'git-sync' — set by the in-process git-sync data
+  // plane (issue #194 §8.1) when it drives PageService writes; never from a request token.
   actor: ProvenanceSource;
   aiChatId: string | null;
 }
@@ -60,6 +62,14 @@ export function agentSourceFields<S extends string, C extends string>(
   sourceKey: S,
   chatKey: C,
 ): Partial<Record<S, ProvenanceSource> & Record<C, string | null>> {
+  // git-sync data-plane write (issue #194 §8.1): stamp the source 'git-sync' with NO
+  // aiChatId (it has no internal ai_chats row). Mirrors the agent branch; each
+  // write has a single actor, so precedence is irrelevant here.
+  if (provenance?.actor === 'git-sync') {
+    return { [sourceKey]: 'git-sync' } as Partial<
+      Record<S, ProvenanceSource> & Record<C, string | null>
+    >;
+  }
   if (provenance?.actor !== 'agent') return {};
   return {
     [sourceKey]: 'agent',

apps/server/src/common/helpers/esm-import.ts

@@ -0,0 +1,18 @@
+/**
+ * Dynamic ESM import bridge for a CommonJS build.
+ *
+ * The server compiles with `module: commonjs`, and TypeScript downlevels a
+ * literal `import()` expression to `require()` — which cannot load an ESM-only
+ * package (`@docmost/mcp`, `@docmost/git-sync`). Indirecting through `new
+ * Function` hides the `import()` from the TS downleveler so the REAL dynamic
+ * `import()` survives to runtime and can load ESM from CommonJS.
+ *
+ * This is the single shared copy of that bridge. The per-package typed loaders
+ * (git-sync.loader.ts, docmost-client.loader.ts, mcp.service.ts) import this and
+ * keep their own typed `loadX()` wrappers (require.resolve + pathToFileURL +
+ * memoization) on top.
+ */
+export const esmImport = new Function(
+  'specifier',
+  'return import(specifier)',
+) as (specifier: string) => Promise<unknown>;

apps/server/src/common/helpers/resolve-request-workspace.spec.ts

@@ -0,0 +1,71 @@
+import { resolveRequestWorkspace } from './resolve-request-workspace';
+
+// Unit tests for the shared self-hosted/cloud workspace resolver deduplicated out
+// of DomainMiddleware + GitHttpService (architecture #11). They must behave
+// identically, so this pins the single source of truth.
+
+type AnyMock = jest.Mock;
+
+function build(opts: {
+  selfHosted: boolean;
+  first?: { id: string } | null;
+  byHostname?: { id: string } | null;
+}) {
+  const env = {
+    isSelfHosted: jest.fn(() => opts.selfHosted),
+    isCloud: jest.fn(() => !opts.selfHosted),
+  };
+  const repo = {
+    findFirst: jest.fn(async () => opts.first ?? null) as AnyMock,
+    findByHostname: jest.fn(async () => opts.byHostname ?? null) as AnyMock,
+  };
+  return { env, repo };
+}
+
+describe('resolveRequestWorkspace', () => {
+  it('self-hosted: returns the first/default workspace, ignoring the host', async () => {
+    const { env, repo } = build({ selfHosted: true, first: { id: 'ws-1' } });
+    const ws = await resolveRequestWorkspace(
+      env as any,
+      repo as any,
+      'anything.example.com',
+    );
+    expect(ws).toEqual({ id: 'ws-1' });
+    expect(repo.findFirst).toHaveBeenCalledTimes(1);
+    expect(repo.findByHostname).not.toHaveBeenCalled();
+  });
+
+  it('self-hosted: returns null when no workspace is configured', async () => {
+    const { env, repo } = build({ selfHosted: true, first: null });
+    expect(await resolveRequestWorkspace(env as any, repo as any, 'h')).toBeNull();
+  });
+
+  it('cloud: resolves by the host-header subdomain', async () => {
+    const { env, repo } = build({
+      selfHosted: false,
+      byHostname: { id: 'ws-acme' },
+    });
+    const ws = await resolveRequestWorkspace(
+      env as any,
+      repo as any,
+      'acme.example.com',
+    );
+    expect(ws).toEqual({ id: 'ws-acme' });
+    expect(repo.findByHostname).toHaveBeenCalledWith('acme');
+    expect(repo.findFirst).not.toHaveBeenCalled();
+  });
+
+  it('cloud: returns null for a blank/missing host (no throw)', async () => {
+    const { env, repo } = build({ selfHosted: false, byHostname: { id: 'x' } });
+    expect(await resolveRequestWorkspace(env as any, repo as any, undefined)).toBeNull();
+    expect(await resolveRequestWorkspace(env as any, repo as any, '')).toBeNull();
+    expect(repo.findByHostname).not.toHaveBeenCalled();
+  });
+
+  it('cloud: returns null when the subdomain matches no workspace', async () => {
+    const { env, repo } = build({ selfHosted: false, byHostname: null });
+    expect(
+      await resolveRequestWorkspace(env as any, repo as any, 'ghost.example.com'),
+    ).toBeNull();
+  });
+});

apps/server/src/common/helpers/resolve-request-workspace.ts

@@ -0,0 +1,35 @@
+import { WorkspaceRepo } from '@docmost/db/repos/workspace/workspace.repo';
+import { Workspace } from '@docmost/db/types/entity.types';
+import { EnvironmentService } from '../../integrations/environment/environment.service';
+
+/**
+ * The ONE canonical way to resolve the workspace for an incoming request:
+ *   - self-hosted (single workspace) -> the first/default workspace;
+ *   - cloud (multi-tenant)           -> resolved by the host-header subdomain.
+ * Returns null when none resolves (no workspace configured, or a blank/unknown
+ * subdomain on cloud). `isSelfHosted()` is `!isCloud()`, so exactly one branch is
+ * always taken.
+ *
+ * Extracted so the self-hosted/cloud branch is not hand-duplicated. Shared by
+ * `DomainMiddleware` (the normal /api request path) and `GitHttpService` (the raw
+ * root-mounted /git smart-HTTP host, which Nest middleware does NOT run for) so
+ * the two cannot drift.
+ *
+ * This helper does NOT catch DB errors — callers decide: DomainMiddleware lets a
+ * throw bubble (as before); GitHttpService wraps it to log + treat as
+ * unresolvable (-> 404). A blank/missing host on cloud resolves to null rather
+ * than throwing.
+ */
+export async function resolveRequestWorkspace(
+  environmentService: EnvironmentService,
+  workspaceRepo: WorkspaceRepo,
+  hostHeader: string | undefined,
+): Promise<Workspace | null> {
+  if (environmentService.isSelfHosted()) {
+    return (await workspaceRepo.findFirst()) ?? null;
+  }
+  // Cloud (isSelfHosted === !isCloud, so this is the only remaining branch).
+  const subdomain = hostHeader ? hostHeader.split('.')[0] : '';
+  if (!subdomain) return null;
+  return (await workspaceRepo.findByHostname(subdomain)) ?? null;
+}

apps/server/src/common/middlewares/domain.middleware.ts

@@ -1,7 +1,8 @@
-import { Injectable, NestMiddleware, NotFoundException } from '@nestjs/common';
+import { Injectable, NestMiddleware } from '@nestjs/common';
 import { FastifyRequest, FastifyReply } from 'fastify';
 import { EnvironmentService } from '../../integrations/environment/environment.service';
 import { WorkspaceRepo } from '@docmost/db/repos/workspace/workspace.repo';
+import { resolveRequestWorkspace } from '../helpers/resolve-request-workspace';
 
 @Injectable()
 export class DomainMiddleware implements NestMiddleware {
@@ -14,30 +15,19 @@ export class DomainMiddleware implements NestMiddleware {
     res: FastifyReply['raw'],
     next: () => void,
   ) {
-    if (this.environmentService.isSelfHosted()) {
-      const workspace = await this.workspaceRepo.findFirst();
-      if (!workspace) {
-        //throw new NotFoundException('Workspace not found');
-        (req as any).workspaceId = null;
-        return next();
-      }
-
-      // TODO: unify
-      (req as any).workspaceId = workspace.id;
-      (req as any).workspace = workspace;
-    } else if (this.environmentService.isCloud()) {
-      const header = req.headers.host;
-      const subdomain = header.split('.')[0];
-
-      const workspace = await this.workspaceRepo.findByHostname(subdomain);
-
-      if (!workspace) {
-        (req as any).workspaceId = null;
-        return next();
-      }
+    // Shared self-hosted/cloud resolution (the SAME branch the /git host uses),
+    // so the logic cannot drift between the two.
+    const workspace = await resolveRequestWorkspace(
+      this.environmentService,
+      this.workspaceRepo,
+      req.headers.host,
+    );
 
+    if (workspace) {
       (req as any).workspaceId = workspace.id;
       (req as any).workspace = workspace;
+    } else {
+      (req as any).workspaceId = null;
     }
 
     next();

apps/server/src/core/ai-chat/external-mcp/mcp-clients.lease.spec.ts

@@ -0,0 +1,157 @@
+import { McpClientsService } from './mcp-clients.service';
+
+/**
+ * #204 (Phase 1, highest-value MCP gap) — external MCP client lease / refcount /
+ * eviction lifecycle.
+ *
+ * `toolsFor` hands the streaming turn a release handle; the real transports must
+ * be closed EXACTLY once and only when (a) the cache entry has been evicted AND
+ * (b) no turn still leases it. The bugs this guards against:
+ *   - leak: an evicted entry whose clients are never closed (refCount stuck > 0);
+ *   - premature close: a TTL/CRUD eviction closing a client a turn is still
+ *     executing tool calls against;
+ *   - double close: a release handle closing the same client more than once.
+ *
+ * The private `buildEntry` is stubbed so no real network/MCP connection happens;
+ * we drive only the lease bookkeeping in `toolsFor` / `release` / `evict` /
+ * `invalidate`, which is the untested surface.
+ */
+describe('McpClientsService lease/refcount/eviction', () => {
+  type FakeClient = { tools: () => Promise<any>; close: jest.Mock };
+
+  function fakeClient(): FakeClient {
+    return {
+      tools: async () => ({}),
+      close: jest.fn().mockResolvedValue(undefined),
+    };
+  }
+
+  // Minimal CacheEntry the service's lease logic operates on.
+  function makeEntry(clients: FakeClient[]) {
+    const timer = setTimeout(() => {}, 60_000);
+    timer.unref?.();
+    return {
+      tools: {},
+      clients,
+      outcomes: [],
+      instructions: [],
+      expiresAt: Date.now() + 60_000,
+      refCount: 0,
+      evicted: false,
+      closed: false,
+      timer,
+    } as any;
+  }
+
+  let service: McpClientsService;
+
+  beforeEach(() => {
+    service = new McpClientsService({} as any, {} as any);
+  });
+
+  function stubBuild(entry: any) {
+    jest.spyOn(service as any, 'buildEntry').mockResolvedValue(entry);
+  }
+
+  it('leases on toolsFor and keeps the client warm (no close) on release', async () => {
+    const client = fakeClient();
+    const entry = makeEntry([client]);
+    stubBuild(entry);
+
+    const lease = await service.toolsFor('ws-1');
+    expect(entry.refCount).toBe(1);
+
+    await lease.clients[0].close();
+    // Released but NOT evicted: the cached entry stays warm for reuse, so the
+    // transport must NOT be closed yet.
+    expect(entry.refCount).toBe(0);
+    expect(client.close).not.toHaveBeenCalled();
+  });
+
+  it('defers close when an entry is evicted while still leased, then closes once on release', async () => {
+    const client = fakeClient();
+    const entry = makeEntry([client]);
+    stubBuild(entry);
+
+    const lease = await service.toolsFor('ws-2');
+    (service as any).evict(entry);
+
+    // Evicted under an active lease: close is deferred to the last release.
+    expect(entry.evicted).toBe(true);
+    expect(client.close).not.toHaveBeenCalled();
+
+    await lease.clients[0].close();
+    expect(client.close).toHaveBeenCalledTimes(1);
+    expect(entry.closed).toBe(true);
+  });
+
+  it('shares one entry across concurrent leases; closes only after the LAST release', async () => {
+    const client = fakeClient();
+    const entry = makeEntry([client]);
+    stubBuild(entry);
+
+    const lease1 = await service.toolsFor('ws-3');
+    const lease2 = await service.toolsFor('ws-3');
+    expect(entry.refCount).toBe(2);
+
+    (service as any).evict(entry);
+
+    await lease1.clients[0].close();
+    // One lease remains: a stream could still be running — must stay open.
+    expect(entry.refCount).toBe(1);
+    expect(client.close).not.toHaveBeenCalled();
+
+    await lease2.clients[0].close();
+    expect(entry.refCount).toBe(0);
+    expect(client.close).toHaveBeenCalledTimes(1);
+  });
+
+  it('release is idempotent: closing the same handle twice decrements once and closes once', async () => {
+    const client = fakeClient();
+    const entry = makeEntry([client]);
+    stubBuild(entry);
+
+    const lease = await service.toolsFor('ws-4');
+    (service as any).evict(entry);
+
+    await lease.clients[0].close();
+    await lease.clients[0].close();
+
+    expect(entry.refCount).toBe(0); // not -1
+    expect(client.close).toHaveBeenCalledTimes(1);
+  });
+
+  it('evicting an unleased entry closes its clients immediately', async () => {
+    const client = fakeClient();
+    const entry = makeEntry([client]);
+    stubBuild(entry);
+
+    const built = await (service as any).getOrBuildEntry('ws-5');
+    expect(built.refCount).toBe(0);
+
+    (service as any).evict(entry);
+    expect(client.close).toHaveBeenCalledTimes(1);
+    expect(entry.closed).toBe(true);
+  });
+
+  it('invalidate (TTL/CRUD) does NOT close a client that a turn still leases', async () => {
+    const client = fakeClient();
+    const entry = makeEntry([client]);
+    stubBuild(entry);
+
+    const lease = await service.toolsFor('ws-6');
+    expect(entry.refCount).toBe(1);
+
+    service.invalidate('ws-6');
+    // invalidate evicts asynchronously once the build promise resolves.
+    await Promise.resolve();
+    await Promise.resolve();
+
+    expect(entry.evicted).toBe(true);
+    // Still leased: the mid-turn eviction must not pull the transport.
+    expect(client.close).not.toHaveBeenCalled();
+
+    await lease.clients[0].close();
+    expect(client.close).toHaveBeenCalledTimes(1);
+  });
+});

apps/server/src/core/ai-chat/tools/docmost-client.loader.ts

@@ -1,4 +1,5 @@
 import { pathToFileURL } from 'node:url';
+import { esmImport } from '../../../common/helpers/esm-import';
 
 /**
  * Minimal structural type for the `DocmostClient` class we consume from the
@@ -192,14 +193,8 @@ interface DocmostMcpModule {
   SHARED_TOOL_SPECS: Record<string, SharedToolSpec>;
 }
 
-// TS with module:commonjs downlevels a literal `import()` to `require()`, which
-// cannot load the ESM-only `@docmost/mcp` package. Indirect through Function so
-// the real dynamic `import()` survives compilation and can load ESM from
-// CommonJS at runtime (same trick as integrations/mcp/mcp.service.ts).
-const esmImport = new Function(
-  'specifier',
-  'return import(specifier)',
-) as (specifier: string) => Promise<unknown>;
+// The CJS->ESM dynamic-import bridge lives in one shared helper
+// (common/helpers/esm-import.ts). The typed `loadDocmostMcp()` wrapper stays here.
 
 // Memoize the in-flight/loaded module so the dynamic import runs at most once.
 let modulePromise: Promise<DocmostMcpModule> | null = null;

apps/server/src/core/auth/dto/jwt-payload.ts

@@ -3,8 +3,12 @@
  * from the SIGNED token claim (never a request body), so 'agent' is unspoofable.
  * Single source of truth so a typo like 'agnet' can't slip through as a bare
  * string (#143 review). Distinct from `ActorType` (auth principal kind).
+ *
+ * 'git-sync' marks writes made by the git-sync data plane (issue #194 §8.1). It NEVER
+ * travels in a user-facing token; it is set in-process on the collab connection
+ * context by the native datasource, so it cannot be spoofed from a request.
  */
-export type ProvenanceSource = 'user' | 'agent';
+export type ProvenanceSource = 'user' | 'agent' | 'git-sync';
 
 export enum JwtType {
   ACCESS = 'access',
@@ -26,7 +30,8 @@ export type JwtPayload = {
   // normal user token (treated as 'user'); set only when the internal agent
   // mints a provenance access token so REST writes (create/rename/move page,
   // comment create/resolve) record a non-spoofable 'agent' marker (§6.5 / §15
-  // C3 / §14 N2).
+  // C3 / §14 N2). (git-sync writes use the in-process actor, not a token — see
+  // the ProvenanceSource note.)
   actor?: ProvenanceSource;
   // Nullable: an external MCP agent has no internal ai_chats row, so it carries
   // an 'agent' actor with a null aiChatId.
@@ -39,7 +44,8 @@ export type JwtCollabPayload = {
   type: 'collab';
   // Optional agent-edit provenance, signed into the collab token. Absent for
   // the human collab path (treated as 'user'); set only when the internal agent
-  // mints a provenance collab token (§6.6 / §15 C2).
+  // mints a provenance collab token (§6.6 / §15 C2). 'git-sync' (in ProvenanceSource)
+  // is accepted for type-compatibility with the in-process git-sync write path.
   actor?: ProvenanceSource;
   // Nullable: an external MCP agent has no internal ai_chats row, so it carries
   // an 'agent' actor with a null aiChatId.

apps/server/src/core/page/services/page.service.footnote-canonicalize.spec.ts

@@ -0,0 +1,153 @@
+// Binding test for issue #228 must-fix #1 / test-coverage #12: footnote
+// canonicalization moved OUT of parseProsemirrorContent and is now applied only
+// on FULL-document writes (createPage, and updatePageContent with operation
+// 'replace'), NEVER on an append/prepend FRAGMENT.
+//
+// The Yjs encode / plain-text extract are stubbed (partial module mock keeps the
+// REAL canonicalizeFootnotes) and parseProsemirrorContent is spied to return the
+// raw fixture, so the test isolates the canonicalize BINDING from schema/Yjs.
+jest.mock('@docmost/editor-ext', () => {
+  const actual = jest.requireActual('@docmost/editor-ext');
+  return {
+    ...actual,
+    createYdocFromJson: jest.fn(() => Buffer.from([])),
+    jsonToText: jest.fn(() => ''),
+  };
+});
+
+import { PageService } from './page.service';
+
+const refNode = (id: string) => ({ type: 'footnoteReference', attrs: { id } });
+const defNode = (id: string, text: string) => ({
+  type: 'footnoteDefinition',
+  attrs: { id },
+  content: [{ type: 'paragraph', content: [{ type: 'text', text }] }],
+});
+const doc = (...content: any[]) => ({ type: 'doc', content });
+
+/** A full doc whose footnote definitions are OUT of reference order (b,a refs;
+ *  a,b defs) — canonicalization must reorder the definitions to [b, a]. */
+const outOfOrderFull = () =>
+  doc(
+    { type: 'paragraph', content: [{ type: 'text', text: 'x' }, refNode('b'), refNode('a')] },
+    { type: 'footnotesList', content: [defNode('a', 'A'), defNode('b', 'B')] },
+  );
+
+/** A definition-ONLY fragment (no references): canonicalizing it would drop the
+ *  whole footnotesList (referenceIds is empty) — i.e. LOSE the footnote. */
+const defOnlyFragment = () =>
+  doc({ type: 'footnotesList', content: [defNode('a', 'appended note')] });
+
+/** A reference-only fragment that REUSES an id defined elsewhere in the live
+ *  doc: canonicalizing it would synthesize a bogus empty footnotesList/def. */
+const refReuseFragment = () =>
+  doc({ type: 'paragraph', content: [{ type: 'text', text: 'more' }, refNode('a')] });
+
+function listDefIds(content: any): string[] {
+  const list = (content.content ?? []).find((n: any) => n.type === 'footnotesList');
+  return (list?.content ?? [])
+    .filter((n: any) => n.type === 'footnoteDefinition')
+    .map((n: any) => n.attrs?.id);
+}
+function hasFootnotesList(content: any): boolean {
+  return (content.content ?? []).some((n: any) => n.type === 'footnotesList');
+}
+
+describe('PageService footnote canonicalization binding (#228)', () => {
+  function makeService() {
+    let insertedContent: any = null;
+    let yjsPayload: any = null;
+
+    const pageRepo = {
+      insertPage: jest.fn(async (values: any) => {
+        insertedContent = values.content;
+        return { id: 'page-id', slugId: 'slug-id' };
+      }),
+    };
+    const generalQueue = { add: jest.fn().mockReturnValue({ catch: jest.fn() }) };
+    const collaborationGateway = {
+      handleYjsEvent: jest.fn(async (_evt: string, _name: string, payload: any) => {
+        yjsPayload = payload;
+      }),
+    };
+
+    const service = new PageService(
+      pageRepo as any,
+      {} as any, // pagePermissionRepo
+      {} as any, // attachmentRepo
+      {} as any, // db
+      {} as any, // storageService
+      {} as any, // attachmentQueue
+      {} as any, // aiQueue
+      generalQueue as any,
+      {} as any, // eventEmitter
+      collaborationGateway as any,
+      {} as any, // watcherService
+      {} as any, // transclusionService
+    );
+    // Isolate the canonicalize BINDING: return the raw fixture (a deep clone so
+    // canonicalize never mutates the caller's object) instead of running the
+    // real markdown/HTML/JSON parse + schema validation.
+    jest
+      .spyOn(service as any, 'parseProsemirrorContent')
+      .mockImplementation(async (content: any) => structuredClone(content));
+    jest.spyOn(service as any, 'nextPagePosition').mockResolvedValue('a0');
+
+    return { service, getInsertedContent: () => insertedContent, getYjsPayload: () => yjsPayload };
+  }
+
+  it('createPage (full write) canonicalizes footnotes into reference order', async () => {
+    const { service, getInsertedContent } = makeService();
+    await service.create('user-id', 'workspace-id', {
+      spaceId: 'space-id',
+      content: outOfOrderFull(),
+      format: 'json',
+    } as any);
+    // Definitions reordered to reference order [b, a].
+    expect(listDefIds(getInsertedContent())).toEqual(['b', 'a']);
+  });
+
+  it("updatePageContent operation 'replace' canonicalizes footnotes", async () => {
+    const { service, getYjsPayload } = makeService();
+    await service.updatePageContent(
+      'page-id',
+      outOfOrderFull(),
+      'replace' as any,
+      'json' as any,
+      { id: 'user-id' } as any,
+    );
+    expect(getYjsPayload().operation).toBe('replace');
+    expect(listDefIds(getYjsPayload().prosemirrorJson)).toEqual(['b', 'a']);
+  });
+
+  it("append of a definition-only fragment is NOT canonicalized (footnote preserved, not dropped)", async () => {
+    const { service, getYjsPayload } = makeService();
+    await service.updatePageContent(
+      'page-id',
+      defOnlyFragment(),
+      'append' as any,
+      'json' as any,
+      { id: 'user-id' } as any,
+    );
+    // Canonicalizing a reference-less fragment would DROP the whole list; the
+    // fragment must pass through untouched so the merge keeps the definition.
+    expect(getYjsPayload().operation).toBe('append');
+    expect(hasFootnotesList(getYjsPayload().prosemirrorJson)).toBe(true);
+    expect(listDefIds(getYjsPayload().prosemirrorJson)).toEqual(['a']);
+  });
+
+  it('prepend of a reference-reuse fragment is NOT canonicalized (no synthesized garbage list)', async () => {
+    const { service, getYjsPayload } = makeService();
+    await service.updatePageContent(
+      'page-id',
+      refReuseFragment(),
+      'prepend' as any,
+      'json' as any,
+      { id: 'user-id' } as any,
+    );
+    // Canonicalizing would synthesize a bogus empty footnotesList for the reused
+    // reference; the fragment must pass through with no list at all.
+    expect(getYjsPayload().operation).toBe('prepend');
+    expect(hasFootnotesList(getYjsPayload().prosemirrorJson)).toBe(false);
+  });
+});

apps/server/src/core/page/services/page.service.spec.ts

@@ -1,8 +1,11 @@
 import { BadRequestException } from '@nestjs/common';
 import { PageService } from './page.service';
 import { MovePageDto } from '../dto/move-page.dto';
-import { Page } from '@docmost/db/types/entity.types';
+import { CreatePageDto } from '../dto/create-page.dto';
+import { UpdatePageDto } from '../dto/update-page.dto';
+import { Page, User } from '@docmost/db/types/entity.types';
 import { DEFAULT_TEMPORARY_NOTE_HOURS } from '../constants/temporary-note.constants';
+import { AuthProvenanceData } from '../../../common/decorators/auth-provenance.decorator';
 
 // Direct instantiation with stub deps. The Test.createTestingModule form failed
 // to resolve the @InjectKysely()/@InjectQueue() tokens at compile(), and this
@@ -496,4 +499,295 @@ describe('PageService', () => {
       expect(db.selectFrom).not.toHaveBeenCalled();
     });
   });
+
+  describe('git-sync provenance stamping (#1)', () => {
+    const GIT_SYNC: AuthProvenanceData = { actor: 'git-sync', aiChatId: null };
+    const USER_PROVENANCE: AuthProvenanceData = { actor: 'user', aiChatId: null };
+
+    describe('create()', () => {
+      // Build a service whose insertPage/generalQueue are observable and whose
+      // nextPagePosition (a DB query) is stubbed, so create() reaches insertPage
+      // without a real database.
+      const makeService = () => {
+        const insertedPage = { id: 'page-1', slugId: 'slug-1' };
+        const pageRepo = {
+          insertPage: jest.fn().mockResolvedValue(insertedPage),
+        };
+        // add() is fire-and-forget (the service .catch()es it); resolve so no
+        // unhandled rejection leaks.
+        const generalQueue = { add: jest.fn().mockResolvedValue(undefined) };
+
+        const svc = new PageService(
+          pageRepo as any, // pageRepo
+          {} as any, // pagePermissionRepo
+          {} as any, // attachmentRepo
+          {} as any, // db
+          {} as any, // storageService
+          {} as any, // attachmentQueue
+          {} as any, // aiQueue
+          generalQueue as any, // generalQueue
+          {} as any, // eventEmitter
+          {} as any, // collaborationGateway
+          {} as any, // watcherService
+          {} as any, // transclusionService
+        );
+
+        // nextPagePosition runs a kysely query; stub it so create() never hits
+        // the db. No DTO content is provided, so parseProsemirrorContent is
+        // skipped entirely (content/textContent/ydoc stay undefined).
+        jest.spyOn(svc, 'nextPagePosition').mockResolvedValue('a0');
+
+        return { svc, pageRepo };
+      };
+
+      const createDto: CreatePageDto = {
+        title: 'New page',
+        spaceId: 'space-1',
+      } as any;
+
+      it("stamps lastUpdatedSource:'git-sync' on the insertPage payload", async () => {
+        const { svc, pageRepo } = makeService();
+
+        await svc.create('user-1', 'ws-1', createDto, GIT_SYNC);
+
+        expect(pageRepo.insertPage).toHaveBeenCalledTimes(1);
+        expect(pageRepo.insertPage).toHaveBeenCalledWith(
+          expect.objectContaining({ lastUpdatedSource: 'git-sync' }),
+        );
+        // git-sync carries no aiChatId (unlike the agent branch).
+        const payload = pageRepo.insertPage.mock.calls[0][0];
+        expect(payload.lastUpdatedAiChatId).toBeUndefined();
+        // The human stays the responsible author.
+        expect(payload.creatorId).toBe('user-1');
+        expect(payload.lastUpdatedById).toBe('user-1');
+      });
+
+      it('leaves the source column unset for a plain user create', async () => {
+        const { svc, pageRepo } = makeService();
+
+        await svc.create('user-1', 'ws-1', createDto, USER_PROVENANCE);
+
+        const payload = pageRepo.insertPage.mock.calls[0][0];
+        expect(payload.lastUpdatedSource).toBeUndefined();
+      });
+    });
+
+    describe('update() (rename)', () => {
+      const makeService = () => {
+        const pageRepo = {
+          updatePage: jest.fn().mockResolvedValue({ numUpdatedRows: 1n }),
+          // update() re-reads the row at the end to return the refreshed page.
+          findById: jest.fn().mockResolvedValue({ id: 'page-1' }),
+        };
+        const generalQueue = { add: jest.fn().mockResolvedValue(undefined) };
+        const aiQueue = { add: jest.fn().mockResolvedValue(undefined) };
+
+        const svc = new PageService(
+          pageRepo as any, // pageRepo
+          {} as any, // pagePermissionRepo
+          {} as any, // attachmentRepo
+          {} as any, // db
+          {} as any, // storageService
+          {} as any, // attachmentQueue
+          aiQueue as any, // aiQueue
+          generalQueue as any, // generalQueue
+          {} as any, // eventEmitter
+          {} as any, // collaborationGateway
+          {} as any, // watcherService
+          {} as any, // transclusionService
+        );
+
+        return { svc, pageRepo };
+      };
+
+      const page: Page = {
+        id: 'page-1',
+        slugId: 'slug-1',
+        spaceId: 'space-1',
+        workspaceId: 'ws-1',
+        title: 'Old title',
+        icon: null,
+        parentPageId: null,
+        contributorIds: [],
+      } as any;
+
+      const user: User = { id: 'user-1' } as any;
+
+      it("stamps lastUpdatedSource:'git-sync' on the updatePage payload", async () => {
+        const { svc, pageRepo } = makeService();
+        const dto: UpdatePageDto = { title: 'New title' } as any;
+
+        await svc.update(page, dto, user, GIT_SYNC);
+
+        expect(pageRepo.updatePage).toHaveBeenCalledTimes(1);
+        const payload = pageRepo.updatePage.mock.calls[0][0];
+        expect(payload.lastUpdatedSource).toBe('git-sync');
+        expect(payload.lastUpdatedAiChatId).toBeUndefined();
+        // The acting user stays the responsible author.
+        expect(payload.lastUpdatedById).toBe('user-1');
+      });
+
+      it('leaves the source column unset for a plain user rename', async () => {
+        const { svc, pageRepo } = makeService();
+        const dto: UpdatePageDto = { title: 'New title' } as any;
+
+        await svc.update(page, dto, user, USER_PROVENANCE);
+
+        const payload = pageRepo.updatePage.mock.calls[0][0];
+        expect(payload.lastUpdatedSource).toBeUndefined();
+      });
+    });
+
+    describe('movePage()', () => {
+      const SPACE_ID = 'space-1';
+      const VALID_POSITION = 'a0';
+
+      const makeService = () => {
+        const pageRepo = {
+          findById: jest.fn().mockResolvedValue({
+            id: 'dest-parent',
+            deletedAt: null,
+            spaceId: SPACE_ID,
+          }),
+          updatePage: jest.fn().mockResolvedValue({ numUpdatedRows: 1n }),
+        };
+        const eventEmitter = { emit: jest.fn() };
+
+        // movePage now runs the cycle-check + UPDATE inside executeTx(this.db),
+        // i.e. this.db.transaction().execute(fn => fn(trx)). A permissive
+        // chainable Proxy stands in for the Kysely trx so the per-space
+        // advisory-lock `sql``.execute(trx)` resolves and updatePage runs.
+        const trxStub: any = new Proxy(function () {}, {
+          get: (_t, p) =>
+            p === 'then'
+              ? undefined
+              : p === 'execute' || p === 'executeTakeFirst'
+                ? () => Promise.resolve([])
+                : () => trxStub,
+        });
+        const db = {
+          transaction: () => ({ execute: (fn: any) => fn(trxStub) }),
+        };
+
+        const svc = new PageService(
+          pageRepo as any, // pageRepo
+          {} as any, // pagePermissionRepo
+          {} as any, // attachmentRepo
+          db as any, // db
+          {} as any, // storageService
+          {} as any, // attachmentQueue
+          {} as any, // aiQueue
+          {} as any, // generalQueue
+          eventEmitter as any, // eventEmitter
+          {} as any, // collaborationGateway
+          {} as any, // watcherService
+          {} as any, // transclusionService
+        );
+
+        // No cycle: the destination's ancestor chain does not contain the moved
+        // page, so movePage reaches updatePage.
+        jest
+          .spyOn(svc, 'getPageBreadCrumbs')
+          .mockResolvedValue([{ id: 'dest-parent' }, { id: 'root' }] as any);
+
+        return { svc, pageRepo };
+      };
+
+      const movedPage: Page = {
+        id: 'page-1',
+        parentPageId: 'old-parent',
+        spaceId: SPACE_ID,
+        workspaceId: 'ws-1',
+        slugId: 'slug-1',
+        title: 'Page 1',
+        icon: null,
+      } as any;
+
+      const dto: MovePageDto = {
+        pageId: 'page-1',
+        position: VALID_POSITION,
+        parentPageId: 'dest-parent',
+      };
+
+      it("stamps lastUpdatedSource:'git-sync' on the updatePage payload", async () => {
+        const { svc, pageRepo } = makeService();
+
+        await svc.movePage(dto, movedPage, GIT_SYNC);
+
+        expect(pageRepo.updatePage).toHaveBeenCalledTimes(1);
+        const payload = pageRepo.updatePage.mock.calls[0][0];
+        expect(payload.lastUpdatedSource).toBe('git-sync');
+        expect(payload.lastUpdatedAiChatId).toBeUndefined();
+      });
+
+      it('leaves the source column unset for a plain user move', async () => {
+        const { svc, pageRepo } = makeService();
+
+        await svc.movePage(dto, movedPage, USER_PROVENANCE);
+
+        const payload = pageRepo.updatePage.mock.calls[0][0];
+        expect(payload.lastUpdatedSource).toBeUndefined();
+      });
+    });
+
+    describe('removePage()', () => {
+      // removePage forwards a `source` 4th arg to pageRepo.removePage: 'git-sync'
+      // for a git-sync-driven soft-delete (so the change-listener loop-guard skips
+      // its own write), undefined otherwise.
+      const makeService = () => {
+        const pageRepo = {
+          removePage: jest.fn().mockResolvedValue(undefined),
+        };
+
+        const svc = new PageService(
+          pageRepo as any, // pageRepo
+          {} as any, // pagePermissionRepo
+          {} as any, // attachmentRepo
+          {} as any, // db
+          {} as any, // storageService
+          {} as any, // attachmentQueue
+          {} as any, // aiQueue
+          {} as any, // generalQueue
+          {} as any, // eventEmitter
+          {} as any, // collaborationGateway
+          {} as any, // watcherService
+          {} as any, // transclusionService
+        );
+
+        return { svc, pageRepo };
+      };
+
+      it("forwards 'git-sync' as the source for a git-sync soft-delete", async () => {
+        const { svc, pageRepo } = makeService();
+
+        await svc.removePage('page-1', 'user-1', 'ws-1', GIT_SYNC);
+
+        expect(pageRepo.removePage).toHaveBeenCalledTimes(1);
+        const [pageId, userId, workspaceId, source] =
+          pageRepo.removePage.mock.calls[0];
+        expect(pageId).toBe('page-1');
+        expect(userId).toBe('user-1');
+        expect(workspaceId).toBe('ws-1');
+        expect(source).toBe('git-sync');
+      });
+
+      it('forwards undefined as the source for a plain user delete', async () => {
+        const { svc, pageRepo } = makeService();
+
+        await svc.removePage('page-1', 'user-1', 'ws-1', USER_PROVENANCE);
+
+        const [, , , source] = pageRepo.removePage.mock.calls[0];
+        expect(source).toBeUndefined();
+      });
+
+      it('forwards undefined as the source when no provenance is given', async () => {
+        const { svc, pageRepo } = makeService();
+
+        await svc.removePage('page-1', 'user-1', 'ws-1');
+
+        const [, , , source] = pageRepo.removePage.mock.calls[0];
+        expect(source).toBeUndefined();
+      });
+    });
+  });
 });

apps/server/src/core/page/services/page.service.ts

@@ -52,7 +52,7 @@ import {
   INTERNAL_LINK_REGEX,
   extractPageSlugId,
 } from '../../../integrations/export/utils';
-import { markdownToHtml } from '@docmost/editor-ext';
+import { markdownToHtml, canonicalizeFootnotes } from '@docmost/editor-ext';
 import { WatcherService } from '../../watcher/watcher.service';
 import { sql } from 'kysely';
 import { TransclusionService } from '../transclusion/transclusion.service';
@@ -160,9 +160,14 @@ export class PageService {
     let ydoc = undefined;
 
     if (createPageDto?.content && createPageDto?.format) {
-      const prosemirrorJson = await this.parseProsemirrorContent(
-        createPageDto.content,
-        createPageDto.format,
+      // createPage always writes a FULL document, so canonicalize footnotes to
+      // the editor's invariant before persisting (issue #228). Pure + idempotent
+      // + shape-safe: a doc with no footnotes is returned unchanged.
+      const prosemirrorJson = canonicalizeFootnotes(
+        await this.parseProsemirrorContent(
+          createPageDto.content,
+          createPageDto.format,
+        ),
       );
 
       content = prosemirrorJson;
@@ -343,7 +348,17 @@ export class PageService {
     format: ContentFormat,
     user: User,
   ): Promise<void> {
-    const prosemirrorJson = await this.parseProsemirrorContent(content, format);
+    let prosemirrorJson = await this.parseProsemirrorContent(content, format);
+
+    // Canonicalize footnotes ONLY for a full-document write ('replace'). For an
+    // append/prepend FRAGMENT, canonicalizing is semantically wrong (it would
+    // drop a definition-only fragment's list, or synthesize a duplicate empty
+    // definition for a fragment reusing an existing id) — the fragment merges
+    // into the live doc where the editor's footnoteSyncPlugin keeps the invariant
+    // (issue #228, must-fix #1).
+    if (operation === 'replace') {
+      prosemirrorJson = canonicalizeFootnotes(prosemirrorJson);
+    }
 
     const documentName = `page.${pageId}`;
     await this.collaborationGateway.handleYjsEvent(
@@ -933,6 +948,12 @@ export class PageService {
     // Optional agent-edit provenance (from the signed access claim). Stamps the
     // source marker when the agent moves a page via REST (§6.6 REST path).
     provenance?: AuthProvenanceData,
+    // Optional responsible author. When set (git-sync), the move is ATTRIBUTED
+    // to that account via `lastUpdatedById` — parity with create/delete/rename,
+    // which all stamp the service user. A normal user move omits it, leaving
+    // `lastUpdatedById` untouched (a reparent is not a content edit, so the
+    // existing author is preserved — unchanged behavior).
+    actorUserId?: string,
   ) {
     // validate position value by attempting to generate a key
     try {
@@ -1002,6 +1023,9 @@ export class PageService {
         {
           position: dto.position,
           parentPageId: parentPageId,
+          // Attribute a git-initiated move to the service account (parity with
+          // create/delete/rename). Omitted for normal user moves -> unchanged.
+          ...(actorUserId ? { lastUpdatedById: actorUserId } : {}),
           // Agent-edit provenance: annotate the source on an agent move. A
           // normal user request leaves the existing source value unchanged.
           ...agentSourceFields(
@@ -1274,8 +1298,18 @@ export class PageService {
     pageId: string,
     userId: string,
     workspaceId: string,
+    // Optional provenance. A git-sync-driven soft-delete stamps
+    // `lastUpdatedSource = 'git-sync'` so the change-listener loop-guard skips
+    // its own write (mirrors the create/update/move provenance branches above).
+    provenance?: AuthProvenanceData,
   ): Promise<void> {
-    await this.pageRepo.removePage(pageId, userId, workspaceId);
+    const isGitSync = provenance?.actor === 'git-sync';
+    await this.pageRepo.removePage(
+      pageId,
+      userId,
+      workspaceId,
+      isGitSync ? 'git-sync' : undefined,
+    );
   }
 
   private async parseProsemirrorContent(
@@ -1301,6 +1335,24 @@ export class PageService {
       }
     }
 
+    // NOTE: footnote canonicalization is intentionally NOT done here. This
+    // method serves BOTH full writes (createPage / updatePageContent with
+    // operation 'replace') AND fragment writes (append / prepend). Canonicalizing
+    // a FRAGMENT is semantically wrong — e.g. a definition-only fragment has no
+    // references, so the canonicalizer would drop its whole footnotesList (lost
+    // footnotes), and a fragment reusing an existing id would synthesize an empty
+    // duplicate definition. The canonicalizer therefore runs only at the
+    // FULL-DOCUMENT callers (createPage, and updatePageContent for 'replace'),
+    // never on a fragment (issue #228, must-fix #1).
+    // (Future consolidation, architecture B: the import services persist via a
+    // different path; folding all of these into one "prepare JSON for persist"
+    // helper would centralize the canonicalize call — left as follow-up.)
+    //
+    // ENFORCEMENT RULE (#228): any NEW FULL-document persist path MUST call
+    // `canonicalizeFootnotes(json)` before writing (see createPage and
+    // updatePageContent 'replace'); append/prepend FRAGMENT writes MUST NOT (it
+    // would drop or duplicate footnotes — that is exactly why this is per-call-site
+    // rather than a single wrapper here).
     try {
       jsonToNode(prosemirrorJson);
     } catch (err) {

apps/server/src/core/share/share-get-shared-page-binding.spec.ts

@@ -0,0 +1,161 @@
+import { NotFoundException } from '@nestjs/common';
+import { ShareService } from './share.service';
+
+/**
+ * Regression for issue #218: public-share content must be bound to the requested
+ * shareId. `getSharedPage` resolves the page off its slug, but when the caller
+ * supplies a shareId it must be reachable THROUGH that exact share — a forged or
+ * mismatched shareId 404s instead of rendering the page off its slug alone. A
+ * request with no shareId keeps the legacy slug-capability behavior.
+ */
+const WS = 'ws-1';
+const PAGE_ID = 'page-uuid-1';
+const OWN_SHARE_ID = 'share-own';
+const OWN_SHARE_KEY = 'ownkey';
+
+function buildService(over: {
+  resolvedShare?: any;
+  ancestorShare?: any; // returned by shareRepo.findById(requestedShareId)
+  ancestorFound?: boolean; // getShareAncestorPage result
+} = {}) {
+  const resolvedShare = over.resolvedShare ?? {
+    id: OWN_SHARE_ID,
+    key: OWN_SHARE_KEY,
+    includeSubPages: false,
+    spaceId: 'space-1',
+    workspaceId: WS,
+  };
+  const page = { id: PAGE_ID, deletedAt: null, content: { type: 'doc' } };
+
+  const shareRepo = {
+    findById: jest.fn(async () => over.ancestorShare ?? null),
+  };
+
+  const service = new ShareService(
+    shareRepo as any,
+    {} as any, // pageRepo (resolveReadableSharePage is spied)
+    {} as any, // pagePermissionRepo
+    {} as any, // db
+    {} as any, // tokenService
+    {} as any, // transclusionService
+    {} as any, // workspaceRepo
+  );
+
+  jest
+    .spyOn(service, 'resolveReadableSharePage')
+    .mockResolvedValue({ share: resolvedShare, page } as any);
+  jest
+    .spyOn(service, 'updatePublicAttachments')
+    .mockResolvedValue(page.content as any);
+  jest
+    .spyOn(service, 'getShareAncestorPage')
+    .mockResolvedValue(over.ancestorFound ? { id: 'anc' } : null);
+
+  return { service, shareRepo, page, resolvedShare };
+}
+
+describe('ShareService.getSharedPage — share binding (#218)', () => {
+  it('returns the page when no shareId is supplied (legacy slug path)', async () => {
+    const { service } = buildService();
+    const out = await service.getSharedPage({ pageId: PAGE_ID } as any, WS);
+    expect(out.page.id).toBe(PAGE_ID);
+  });
+
+  it('returns the page when the shareId matches the resolved share key', async () => {
+    const { service } = buildService();
+    const out = await service.getSharedPage(
+      { pageId: PAGE_ID, shareId: OWN_SHARE_KEY } as any,
+      WS,
+    );
+    expect(out.page.id).toBe(PAGE_ID);
+  });
+
+  it('returns the page when the shareId matches the resolved share id (case-insensitive key)', async () => {
+    const { service } = buildService();
+    const out = await service.getSharedPage(
+      { pageId: PAGE_ID, shareId: OWN_SHARE_KEY.toUpperCase() } as any,
+      WS,
+    );
+    expect(out.page.id).toBe(PAGE_ID);
+  });
+
+  it('404s for a forged shareId that resolves to nothing', async () => {
+    const { service } = buildService({ ancestorShare: null });
+    await expect(
+      service.getSharedPage(
+        { pageId: PAGE_ID, shareId: 'doesnotexist99' } as any,
+        WS,
+      ),
+    ).rejects.toBeInstanceOf(NotFoundException);
+  });
+
+  it('allows an includeSubPages ANCESTOR share that contains the page', async () => {
+    const { service } = buildService({
+      ancestorShare: {
+        id: 'ancestor-share',
+        pageId: 'ancestor-page',
+        includeSubPages: true,
+        workspaceId: WS,
+      },
+      ancestorFound: true,
+    });
+    const out = await service.getSharedPage(
+      { pageId: PAGE_ID, shareId: 'ancestorkey' } as any,
+      WS,
+    );
+    expect(out.page.id).toBe(PAGE_ID);
+  });
+
+  it('404s for a different share WITHOUT includeSubPages', async () => {
+    const { service } = buildService({
+      ancestorShare: {
+        id: 'other-share',
+        pageId: 'other-page',
+        includeSubPages: false,
+        workspaceId: WS,
+      },
+    });
+    await expect(
+      service.getSharedPage(
+        { pageId: PAGE_ID, shareId: 'otherkey' } as any,
+        WS,
+      ),
+    ).rejects.toBeInstanceOf(NotFoundException);
+  });
+
+  it('404s for an includeSubPages share that does NOT contain the page', async () => {
+    const { service } = buildService({
+      ancestorShare: {
+        id: 'unrelated-share',
+        pageId: 'unrelated-page',
+        includeSubPages: true,
+        workspaceId: WS,
+      },
+      ancestorFound: false,
+    });
+    await expect(
+      service.getSharedPage(
+        { pageId: PAGE_ID, shareId: 'unrelatedkey' } as any,
+        WS,
+      ),
+    ).rejects.toBeInstanceOf(NotFoundException);
+  });
+
+  it('404s for a share in a different workspace', async () => {
+    const { service } = buildService({
+      ancestorShare: {
+        id: 'foreign-share',
+        pageId: 'foreign-page',
+        includeSubPages: true,
+        workspaceId: 'other-ws',
+      },
+      ancestorFound: true,
+    });
+    await expect(
+      service.getSharedPage(
+        { pageId: PAGE_ID, shareId: 'foreignkey' } as any,
+        WS,
+      ),
+    ).rejects.toBeInstanceOf(NotFoundException);
+  });
+});

apps/server/src/core/share/share-public-payload.ts

@@ -0,0 +1,69 @@
+import { Page } from '@docmost/db/types/entity.types';
+
+/**
+ * The EXACT shape returned to anonymous public-share viewers by the
+ * `/shares/page-info` route — the only unauthenticated path that serializes the
+ * full {page, share} records. This is a security boundary (#218): the raw rows
+ * carry internal metadata — creatorId/lastUpdatedById/contributorIds,
+ * spaceId/workspaceId, AI/source bookkeeping, lock/template flags,
+ * parent/position and raw timestamps — none of which may leak to an
+ * unauthenticated viewer. Keeping the allowlist as an explicit TYPE plus a
+ * single mapper means a new leaking field cannot be returned without also
+ * widening this contract (and tripping its key-test in share.controller.spec.ts).
+ */
+export interface PublicSharePayload {
+  page: {
+    id: string;
+    slugId: string;
+    title: string | null;
+    icon: string | null;
+    content: unknown;
+  };
+  share: {
+    id: string;
+    key: string;
+    includeSubPages: boolean | null;
+    searchIndexing: boolean | null;
+    level: number;
+    sharedPage: unknown;
+  };
+}
+
+/**
+ * The subset of the resolved share read by the public payload. Declared
+ * structurally so the richer getShareForPage result (which adds `level` and
+ * `sharedPage` on top of the base Shares row) passes without a cast.
+ */
+interface PublicShareSource {
+  id: string;
+  key: string;
+  includeSubPages: boolean | null;
+  searchIndexing: boolean | null;
+  // `level` is derived via a SQL literal in getShareForPage, so it surfaces as
+  // `unknown` in the resolved share; it is a number at runtime.
+  level: unknown;
+  sharedPage: unknown;
+}
+
+export function toPublicSharePayload(
+  page: Page,
+  share: PublicShareSource,
+): PublicSharePayload {
+  return {
+    page: {
+      id: page.id,
+      slugId: page.slugId,
+      title: page.title,
+      icon: page.icon,
+      content: page.content,
+    },
+    share: {
+      id: share.id,
+      key: share.key,
+      includeSubPages: share.includeSubPages,
+      searchIndexing: share.searchIndexing,
+      level: share.level as number,
+      sharedPage: share.sharedPage,
+    },
+  };
+}

apps/server/src/core/share/share.controller.spec.ts

@@ -0,0 +1,190 @@
+import { ShareController } from './share.controller';
+import {
+  PublicSharePayload,
+  toPublicSharePayload,
+} from './share-public-payload';
+
+// The `/shares/page-info` route is the ONLY anonymous path that serializes the
+// full {page, share} records. Trimming the response to an explicit allowlist is
+// a security control (#218): a regression that returns `...shareData` (or adds a
+// new field to the allowlist) must fail loudly. These tests lock the exact key
+// set returned to anonymous viewers so internal metadata can never silently leak.
+
+const PAGE_KEYS = ['id', 'slugId', 'title', 'icon', 'content'].sort();
+const SHARE_KEYS = [
+  'id',
+  'key',
+  'includeSubPages',
+  'searchIndexing',
+  'level',
+  'sharedPage',
+].sort();
+
+// A page row carrying internal metadata that MUST NOT reach anonymous viewers.
+function internalPage() {
+  return {
+    id: 'page-1',
+    slugId: 'slug-1',
+    title: 'Public Title',
+    icon: '📄',
+    content: { type: 'doc', content: [] },
+    // --- leaky internals ---
+    creatorId: 'user-1',
+    lastUpdatedById: 'user-2',
+    contributorIds: ['user-1', 'user-2'],
+    spaceId: 'space-1',
+    workspaceId: 'ws-1',
+    parentPageId: 'parent-1',
+    position: 'aa',
+    isLocked: true,
+    isTemplate: false,
+    textContent: 'secret text content',
+    ydoc: Buffer.from('binary'),
+    createdAt: new Date('2020-01-01'),
+    updatedAt: new Date('2020-01-02'),
+    deletedAt: null,
+  } as any;
+}
+
+// A resolved share carrying internal metadata.
+function internalShare() {
+  return {
+    id: 'share-1',
+    key: 'share-key',
+    includeSubPages: false,
+    searchIndexing: true,
+    level: 0,
+    sharedPage: { id: 'page-1', slugId: 'slug-1', title: 'Public Title' },
+    // --- leaky internals ---
+    creatorId: 'user-1',
+    spaceId: 'space-1',
+    workspaceId: 'ws-1',
+    pageId: 'page-1',
+    createdAt: new Date('2020-01-01'),
+    updatedAt: new Date('2020-01-02'),
+    deletedAt: null,
+  } as any;
+}
+
+function buildController(over?: { aiAssistant?: boolean }) {
+  const shareService = {
+    // Deliberately returns the FULL internal records (as the real service does).
+    getSharedPage: jest.fn(async () => ({
+      page: internalPage(),
+      share: internalShare(),
+    })),
+    isSharingAllowed: jest.fn(async () => true),
+  };
+  const aiSettings = {
+    isPublicShareAssistantEnabled: jest.fn(
+      async () => over?.aiAssistant ?? false,
+    ),
+    resolvePublicShareAssistantName: jest.fn(async () => 'Assistant'),
+  };
+  const licenseCheckService = {
+    resolveFeatures: jest.fn(() => ({ tier: 'free' })),
+  };
+
+  const controller = new ShareController(
+    shareService as any,
+    {} as any, // shareRepo
+    {} as any, // pageRepo
+    {} as any, // pagePermissionRepo
+    {} as any, // pageAccessService
+    licenseCheckService as any,
+    aiSettings as any,
+    {} as any, // auditService
+  );
+
+  return { controller, shareService, aiSettings, licenseCheckService };
+}
+
+const workspace = {
+  id: 'ws-1',
+  licenseKey: null,
+  plan: 'free',
+} as any;
+
+describe('ShareController.getSharedPageInfo — public payload whitelist (#218)', () => {
+  it('returns EXACTLY the page allowlist keys (no leaked internals)', async () => {
+    const { controller } = buildController();
+
+    const res = await controller.getSharedPageInfo(
+      { pageId: 'page-1' } as any,
+      workspace,
+    );
+
+    expect(Object.keys(res.page).sort()).toEqual(PAGE_KEYS);
+    for (const leaked of [
+      'creatorId',
+      'lastUpdatedById',
+      'contributorIds',
+      'spaceId',
+      'workspaceId',
+      'parentPageId',
+      'position',
+      'textContent',
+      'ydoc',
+      'createdAt',
+      'updatedAt',
+      'deletedAt',
+    ]) {
+      expect((res.page as any)[leaked]).toBeUndefined();
+    }
+    // The serialized payload must not carry the secret text content either.
+    expect(JSON.stringify(res.page)).not.toContain('secret text content');
+  });
+
+  it('returns EXACTLY the share allowlist keys (no leaked internals)', async () => {
+    const { controller } = buildController();
+
+    const res = await controller.getSharedPageInfo(
+      { pageId: 'page-1' } as any,
+      workspace,
+    );
+
+    expect(Object.keys(res.share).sort()).toEqual(SHARE_KEYS);
+    for (const leaked of [
+      'creatorId',
+      'spaceId',
+      'workspaceId',
+      'pageId',
+      'createdAt',
+      'updatedAt',
+      'deletedAt',
+    ]) {
+      expect((res.share as any)[leaked]).toBeUndefined();
+    }
+  });
+
+  it('surfaces the public AI-assistant flags and license features alongside the trimmed payload', async () => {
+    const { controller } = buildController({ aiAssistant: true });
+
+    const res = await controller.getSharedPageInfo(
+      { pageId: 'page-1' } as any,
+      workspace,
+    );
+
+    expect(res.aiAssistant).toBe(true);
+    expect(res.aiAssistantName).toBe('Assistant');
+    expect(res.features).toEqual({ tier: 'free' });
+    // Top-level keys are limited to the trimmed payload + the public extras.
+    expect(Object.keys(res).sort()).toEqual(
+      ['page', 'share', 'aiAssistant', 'aiAssistantName', 'features'].sort(),
+    );
+  });
+});
+
+describe('toPublicSharePayload — key set is the contract', () => {
+  it('copies only the allowlisted page/share keys', () => {
+    const payload: PublicSharePayload = toPublicSharePayload(
+      internalPage(),
+      internalShare(),
+    );
+
+    expect(Object.keys(payload.page).sort()).toEqual(PAGE_KEYS);
+    expect(Object.keys(payload.share).sort()).toEqual(SHARE_KEYS);
+    expect(payload.page.id).toBe('page-1');
+    expect(payload.share.key).toBe('share-key');
+  });
+});

apps/server/src/core/share/share.controller.ts

@@ -36,6 +36,7 @@ import {
   IAuditService,
 } from '../../integrations/audit/audit.service';
 import { AiSettingsService } from '../../integrations/ai/ai-settings.service';
+import { toPublicSharePayload } from './share-public-payload';
 
 @UseGuards(JwtAuthGuard)
 @Controller('shares')
@@ -93,8 +94,13 @@ export class ShareController {
       ? await this.aiSettings.resolvePublicShareAssistantName(workspace.id)
       : null;
 
+    // Trim the public payload to the explicit allowlist the anonymous renderer
+    // needs (#218); the PublicSharePayload type + mapper guarantee internal
+    // metadata can never leak to anonymous viewers (see share-public-payload.ts).
+    const { page, share } = shareData;
+
     return {
-      ...shareData,
+      ...toPublicSharePayload(page, share),
       aiAssistant,
       aiAssistantName,
       features: this.licenseCheckService.resolveFeatures(

apps/server/src/core/share/share.service.ts

@@ -189,9 +189,9 @@ export class ShareService {
   }
 
   async getSharedPage(dto: ShareInfoDto, workspaceId: string) {
-    // Resolve via the single canonical boundary. There is no independent
-    // requested shareId here (the share is resolved FROM the page), so no
-    // share-id match is performed.
+    // Resolve via the single canonical boundary. The share is resolved FROM the
+    // page (the request carries the page slug), so the boundary itself performs
+    // no share-id match here.
     const resolved = await this.resolveReadableSharePage(
       null,
       dto.pageId,
@@ -205,11 +205,85 @@ export class ShareService {
 
     const { share, page } = resolved;
 
+    // Bind content to the requested share (#218). When the caller supplies a
+    // shareId/key (the `/share/:shareId/p/:slug` route now forwards it), the
+    // page must be reachable THROUGH that exact share — a forged or mismatched
+    // shareId must 404 instead of rendering the page off its slug alone, and it
+    // must not be answerable with the page's real (canonical) share key. A
+    // request with no shareId keeps the legacy slug-capability behavior (the
+    // `/share/p/:slug` route + internal title look-ups); the slug nanoid stays
+    // the access secret there — an inherited Docmost design we don't widen.
+    // FUTURE: this ancestor-aware match could fold INTO resolveReadableSharePage
+    // (so the boundary's narrow `share.id === shareId` gate isn't effectively
+    // dead). Deferred — it widens the contract for the 3 other callers that pass
+    // no shareId (share-alias.controller, share-alias.service, share-seo.controller);
+    // the two ai-chat callers (public-share-chat.controller,
+    // public-share-chat-tools.service) already pass a real shareId. Kept here as
+    // a local post-check until that consolidation is worth the blast radius.
+    if (dto.shareId) {
+      const reachable = await this.isPageReachableThroughShare(
+        dto.shareId,
+        share,
+        page.id,
+        workspaceId,
+      );
+      if (!reachable) {
+        throw new NotFoundException('Shared page not found');
+      }
+    }
+
     page.content = await this.updatePublicAttachments(page);
 
     return { page, share };
   }
 
+  /**
+   * Does `requestedShareId` (a share id OR key) legitimately grant access to
+   * `pageId`? True when it names the page's own resolved share, or an ancestor
+   * share with `includeSubPages` that contains the page. Any other value
+   * (unknown key, wrong workspace, a sibling share that doesn't cover the page)
+   * is false, so a guessed slug paired with a forged shareId can't render.
+   */
+  private async isPageReachableThroughShare(
+    requestedShareId: string,
+    resolvedShare: NonNullable<
+      Awaited<ReturnType<ShareService['getShareForPage']>>
+    >,
+    pageId: string,
+    workspaceId: string,
+  ): Promise<boolean> {
+    // Fast path: the request names the page's own resolved share.
+    if (this.shareIdGrantsAccess(requestedShareId, resolvedShare)) {
+      return true;
+    }
+
+    // Otherwise it may name an includeSubPages ANCESTOR share: the page has its
+    // own closer share but is also served under the ancestor's public tree.
+    const requested = await this.shareRepo.findById(requestedShareId);
+    if (!requested || requested.workspaceId !== workspaceId) return false;
+    if (!requested.includeSubPages) return false;
+
+    const ancestor = await this.getShareAncestorPage(requested.pageId, pageId);
+    return !!ancestor;
+  }
+
+  /**
+   * Does the requested share id/key directly name `resolvedShare` — by id, or
+   * by key (case-insensitive)? This is the "names the page's OWN share" half of
+   * the access concept; ancestor includeSubPages shares are matched separately.
+   * Intentionally narrower than `resolveReadableSharePage`'s id-only gate, which
+   * keeps its own contract for the callers that pass a shareId there.
+   */
+  private shareIdGrantsAccess(
+    requestedShareId: string,
+    resolvedShare: { id: string; key?: string | null },
+  ): boolean {
+    return (
+      requestedShareId === resolvedShare.id ||
+      requestedShareId.toLowerCase() === resolvedShare.key?.toLowerCase()
+    );
+  }
+
   async getShareForPage(pageId: string, workspaceId: string) {
     // here we try to check if a page was shared directly or if it inherits the share from its closest shared ancestor
     const share = await this.db
@@ -351,7 +425,14 @@ export class ShareService {
         .limit(1)
         .executeTakeFirst();
     } catch (err) {
-      // empty
+      // Fail closed (return null -> caller 404s), but never silently: this is
+      // now a live public-share path (isPageReachableThroughShare), so a
+      // transient DB error here would otherwise turn a legitimate viewer of an
+      // includeSubPages descendant into a misleading "not found" with no trace.
+      this.logger.error(
+        `getShareAncestorPage failed (ancestorPageId=${ancestorPageId}, childPageId=${childPageId})`,
+        err instanceof Error ? err.stack : String(err),
+      );
     }
 
     return ancestor;

apps/server/src/core/space/dto/update-space.dto.ts

@@ -15,4 +15,12 @@ export class UpdateSpaceDto extends PartialType(CreateSpaceDto) {
   @IsOptional()
   @IsBoolean()
   allowViewerComments: boolean;
+
+  @IsOptional()
+  @IsBoolean()
+  gitSyncEnabled?: boolean;
+
+  @IsOptional()
+  @IsBoolean()
+  autoMergeConflicts?: boolean;
 }

apps/server/src/core/space/services/space.service.spec.ts

@@ -22,4 +22,199 @@ describe('SpaceService', () => {
   it('should be defined', () => {
     expect(service).toBeDefined();
   });
+
+  describe('updateSpace gitSyncEnabled', () => {
+    const workspaceId = 'ws-1';
+    const spaceId = 'space-1';
+
+    // executeTx runs the callback immediately with a passthrough trx so the
+    // repo calls happen inline; mirrors how the sibling sharing/comments flags
+    // are persisted.
+    const buildService = (settingsBefore: Record<string, any>) => {
+      const spaceRepo = {
+        findById: jest.fn().mockResolvedValue({
+          id: spaceId,
+          name: 'Space',
+          slug: 'space',
+          description: '',
+          settings: settingsBefore,
+        }),
+        updateGitSyncSettings: jest.fn().mockResolvedValue({}),
+        updateSharingSettings: jest.fn().mockResolvedValue({}),
+        updateCommentSettings: jest.fn().mockResolvedValue({}),
+        updateSpace: jest
+          .fn()
+          .mockResolvedValue({ id: spaceId, name: 'Space', slug: 'space' }),
+        slugExists: jest.fn().mockResolvedValue(false),
+      };
+      const auditService = { log: jest.fn() };
+
+      const svc = new SpaceService(
+        spaceRepo as any,
+        {} as any, // spaceMemberService
+        {} as any, // shareRepo
+        {} as any, // workspaceRepo
+        {} as any, // licenseCheckService
+        {} as any, // db
+        {} as any, // attachmentQueue
+        auditService as any,
+      );
+
+      // executeTx is invoked via the imported helper; patch it on the module.
+      jest
+        .spyOn(require('@docmost/db/utils'), 'executeTx')
+        .mockImplementation(async (_db: any, cb: any) => cb({} as any));
+
+      return { svc, spaceRepo, auditService };
+    };
+
+    it('persists gitSyncEnabled via updateGitSyncSettings(enabled)', async () => {
+      const { svc, spaceRepo } = buildService({});
+
+      await svc.updateSpace(
+        { spaceId, gitSyncEnabled: true } as any,
+        workspaceId,
+      );
+
+      expect(spaceRepo.updateGitSyncSettings).toHaveBeenCalledWith(
+        spaceId,
+        workspaceId,
+        'enabled',
+        true,
+        expect.anything(),
+      );
+    });
+
+    it('does not call updateGitSyncSettings when flag is undefined', async () => {
+      const { svc, spaceRepo } = buildService({});
+
+      await svc.updateSpace({ spaceId } as any, workspaceId);
+
+      expect(spaceRepo.updateGitSyncSettings).not.toHaveBeenCalled();
+    });
+
+    // --- audit delta on the git-sync toggle (test-strategy Module 4 / item #5)
+    // updateSpace builds a before/after delta only when a flag's value actually
+    // changes, and only logs an audit event when that delta is non-empty. These
+    // assert that contract specifically for gitSyncEnabled.
+    it('writes a SPACE_UPDATED audit delta on a REAL gitSyncEnabled change (false -> true)', async () => {
+      // Prior persisted state: gitSync.enabled = false; the request flips it on.
+      const { svc, auditService } = buildService({ gitSync: { enabled: false } });
+
+      await svc.updateSpace(
+        { spaceId, gitSyncEnabled: true } as any,
+        workspaceId,
+      );
+
+      expect(auditService.log).toHaveBeenCalledTimes(1);
+      expect(auditService.log).toHaveBeenCalledWith(
+        expect.objectContaining({
+          resourceId: spaceId,
+          spaceId,
+          changes: {
+            before: expect.objectContaining({ gitSyncEnabled: false }),
+            after: expect.objectContaining({ gitSyncEnabled: true }),
+          },
+        }),
+      );
+    });
+
+    it('also records the delta when no prior gitSync settings exist (undefined -> true defaults prev to false)', async () => {
+      // No gitSync key at all: prev resolves to the `?? false` default, so
+      // enabling it is still a real change and is audited.
+      const { svc, auditService } = buildService({});
+
+      await svc.updateSpace(
+        { spaceId, gitSyncEnabled: true } as any,
+        workspaceId,
+      );
+
+      expect(auditService.log).toHaveBeenCalledTimes(1);
+      const call = auditService.log.mock.calls[0][0];
+      expect(call.changes.before.gitSyncEnabled).toBe(false);
+      expect(call.changes.after.gitSyncEnabled).toBe(true);
+    });
+
+    it('does NOT write an audit delta on a no-op gitSyncEnabled (same value true -> true)', async () => {
+      // Prior persisted state already true; the request sets the same value.
+      // updateGitSyncSettings still runs (idempotent persist), but nothing is
+      // added to the before/after delta, so no audit event is emitted.
+      const { svc, spaceRepo, auditService } = buildService({
+        gitSync: { enabled: true },
+      });
+
+      await svc.updateSpace(
+        { spaceId, gitSyncEnabled: true } as any,
+        workspaceId,
+      );
+
+      expect(spaceRepo.updateGitSyncSettings).toHaveBeenCalledTimes(1);
+      expect(auditService.log).not.toHaveBeenCalled();
+    });
+
+    // --- autoMergeConflicts: a SECOND key in the SAME `gitSync` jsonb object,
+    // persisted the same way as `enabled` (the repo's jsonb-merge keeps siblings).
+    it('persists autoMergeConflicts via updateGitSyncSettings(autoMergeConflicts)', async () => {
+      const { svc, spaceRepo } = buildService({});
+
+      await svc.updateSpace(
+        { spaceId, autoMergeConflicts: true } as any,
+        workspaceId,
+      );
+
+      expect(spaceRepo.updateGitSyncSettings).toHaveBeenCalledWith(
+        spaceId,
+        workspaceId,
+        'autoMergeConflicts',
+        true,
+        expect.anything(),
+      );
+    });
+
+    it('does not call updateGitSyncSettings when autoMergeConflicts is undefined', async () => {
+      const { svc, spaceRepo } = buildService({});
+
+      await svc.updateSpace({ spaceId } as any, workspaceId);
+
+      expect(spaceRepo.updateGitSyncSettings).not.toHaveBeenCalled();
+    });
+
+    it('writes a SPACE_UPDATED audit delta on a REAL autoMergeConflicts change (false -> true)', async () => {
+      // Prior persisted state: gitSync.autoMergeConflicts = false; flip it on.
+      const { svc, auditService } = buildService({
+        gitSync: { autoMergeConflicts: false },
+      });
+
+      await svc.updateSpace(
+        { spaceId, autoMergeConflicts: true } as any,
+        workspaceId,
+      );
+
+      expect(auditService.log).toHaveBeenCalledTimes(1);
+      expect(auditService.log).toHaveBeenCalledWith(
+        expect.objectContaining({
+          resourceId: spaceId,
+          spaceId,
+          changes: {
+            before: expect.objectContaining({ autoMergeConflicts: false }),
+            after: expect.objectContaining({ autoMergeConflicts: true }),
+          },
+        }),
+      );
+    });
+
+    it('does NOT write an audit delta on a no-op autoMergeConflicts (same value true -> true)', async () => {
+      const { svc, spaceRepo, auditService } = buildService({
+        gitSync: { autoMergeConflicts: true },
+      });
+
+      await svc.updateSpace(
+        { spaceId, autoMergeConflicts: true } as any,
+        workspaceId,
+      );
+
+      expect(spaceRepo.updateGitSyncSettings).toHaveBeenCalledTimes(1);
+      expect(auditService.log).not.toHaveBeenCalled();
+    });
+  });
 });

apps/server/src/core/space/services/space.service.ts

@@ -213,6 +213,41 @@ export class SpaceService {
         );
       }
 
+      if (typeof updateSpaceDto.gitSyncEnabled !== 'undefined') {
+        const prev = settingsBefore?.gitSync?.enabled ?? false;
+        if (prev !== updateSpaceDto.gitSyncEnabled) {
+          before.gitSyncEnabled = prev;
+          after.gitSyncEnabled = updateSpaceDto.gitSyncEnabled;
+        }
+
+        await this.spaceRepo.updateGitSyncSettings(
+          updateSpaceDto.spaceId,
+          workspaceId,
+          'enabled',
+          updateSpaceDto.gitSyncEnabled,
+          trx,
+        );
+      }
+
+      if (typeof updateSpaceDto.autoMergeConflicts !== 'undefined') {
+        const prev = settingsBefore?.gitSync?.autoMergeConflicts ?? false;
+        if (prev !== updateSpaceDto.autoMergeConflicts) {
+          before.autoMergeConflicts = prev;
+          after.autoMergeConflicts = updateSpaceDto.autoMergeConflicts;
+        }
+
+        // Merges into the SAME `gitSync` jsonb object as `enabled` (the repo's
+        // jsonb-merge preserves sibling keys), so toggling one never clobbers the
+        // other.
+        await this.spaceRepo.updateGitSyncSettings(
+          updateSpaceDto.spaceId,
+          workspaceId,
+          'autoMergeConflicts',
+          updateSpaceDto.autoMergeConflicts,
+          trx,
+        );
+      }
+
       updatedSpace = await this.spaceRepo.updateSpace(
         {
           name: updateSpaceDto.name,

apps/server/src/database/repos/page/page.repo.spec.ts

@@ -0,0 +1,157 @@
+import {
+  Kysely,
+  CamelCasePlugin,
+  DummyDriver,
+  PostgresAdapter,
+  PostgresIntrospector,
+  PostgresQueryCompiler,
+  CompiledQuery,
+} from 'kysely';
+import { PageRepo } from './page.repo';
+import type { KyselyDB } from '../../types/kysely.types';
+
+/**
+ * SQL-builder unit test for the git-sync provenance stamp on PageRepo's
+ * soft-delete / restore paths (PR #119 review). Both `removePage` and
+ * `restorePage` take an optional `lastUpdatedSource` arg and conditionally fold
+ * it into the recursive-subtree `UPDATE pages SET ...` via
+ * `...(lastUpdatedSource ? { lastUpdatedSource } : {})`. The change-listener
+ * loop-guard reads `last_updated_source = 'git-sync'` to recognize git-sync's own
+ * writes and skip the echo cycle; this test guards that the stamp is present when
+ * the arg is supplied and ABSENT when it is omitted (an ordinary user delete must
+ * not clobber the column).
+ *
+ * Harness: the same compile-only Kysely/DummyDriver pattern as
+ * space.repo.spec.ts, plus the production `CamelCasePlugin` (so the compiled SQL
+ * carries the real snake_case column names, e.g. `last_updated_source`) and a
+ * thin driver that returns ONE fixed row for every query. The fixed row is what
+ * lets the repo's guard reads (root snapshot / recursive descendants / restore
+ * target) resolve non-empty so execution reaches the subtree UPDATE we assert on
+ * — a bare DummyDriver returns no rows and both methods short-circuit before the
+ * update. We never hit a real database; we capture each compiled statement via
+ * Kysely's `log` hook and inspect the `update "pages" set ...` SQL.
+ */
+describe('PageRepo — git-sync provenance on soft-delete / restore SQL', () => {
+  // A single row shaped to satisfy every column the repo reads off its guard
+  // queries. `parentPageId: null` keeps restorePage on the simple path (no
+  // parent-detach UPDATE), so the only `update "pages"` statement is the one we
+  // assert on.
+  const FIXED_ROW = {
+    id: 'p1',
+    slugId: 's1',
+    title: 'Doc',
+    icon: null,
+    position: 'a0',
+    spaceId: 'space-1',
+    parentPageId: null,
+    deletedAt: null,
+  };
+
+  class FixedRowDriver extends DummyDriver {
+    async acquireConnection(): Promise<any> {
+      return {
+        async executeQuery() {
+          return { rows: [{ ...FIXED_ROW }] };
+        },
+        // eslint-disable-next-line @typescript-eslint/no-empty-function
+        async *streamQuery() {},
+      };
+    }
+  }
+
+  interface Captured {
+    sql: string;
+    parameters: readonly unknown[];
+  }
+
+  // Compile-only Kysely on the Postgres dialect (CamelCasePlugin for real column
+  // names) whose `log` hook records every executed statement's compiled SQL.
+  function makeRepoCapturingSql() {
+    const captured: Captured[] = [];
+    const db = new Kysely<any>({
+      dialect: {
+        createAdapter: () => new PostgresAdapter(),
+        createDriver: () => new FixedRowDriver(),
+        createIntrospector: (d) => new PostgresIntrospector(d),
+        createQueryCompiler: () => new PostgresQueryCompiler(),
+      },
+      plugins: [new CamelCasePlugin()],
+      log: (event) => {
+        if (event.level === 'query') {
+          const q = event.query as CompiledQuery;
+          captured.push({ sql: q.sql, parameters: q.parameters });
+        }
+      },
+    });
+
+    const repo = new PageRepo(
+      db as unknown as KyselyDB,
+      {} as any,
+      { emit: jest.fn() } as any,
+    );
+    // Find the single subtree UPDATE on pages (collapse whitespace for matching).
+    const getUpdatePagesSql = (): Captured | undefined =>
+      captured
+        .map((c) => ({ ...c, sql: c.sql.replace(/\s+/g, ' ') }))
+        .find((c) => /update "pages" set/i.test(c.sql));
+    return { repo, getUpdatePagesSql };
+  }
+
+  describe('removePage', () => {
+    it("stamps last_updated_source = 'git-sync' on the subtree soft-delete when the provenance arg is supplied", async () => {
+      const { repo, getUpdatePagesSql } = makeRepoCapturingSql();
+
+      await repo.removePage('p1', 'user-1', 'ws-1', 'git-sync');
+
+      const update = getUpdatePagesSql();
+      expect(update).toBeDefined();
+      // The provenance column is in the UPDATE's SET clause...
+      expect(update!.sql).toContain('"last_updated_source" =');
+      // ...with the 'git-sync' marker as the bound value.
+      expect(update!.parameters).toContain('git-sync');
+      // Sanity: it is still the soft-delete UPDATE (sets deleted_at too).
+      expect(update!.sql).toContain('"deleted_at" =');
+    });
+
+    it('OMITS last_updated_source from the soft-delete when the provenance arg is undefined', async () => {
+      const { repo, getUpdatePagesSql } = makeRepoCapturingSql();
+
+      await repo.removePage('p1', 'user-1', 'ws-1');
+
+      const update = getUpdatePagesSql();
+      expect(update).toBeDefined();
+      // Ordinary user delete: the column must NOT be touched (keeps prior value).
+      expect(update!.sql).not.toContain('last_updated_source');
+      expect(update!.parameters).not.toContain('git-sync');
+      // It is still the soft-delete UPDATE.
+      expect(update!.sql).toContain('"deleted_at" =');
+    });
+  });
+
+  describe('restorePage', () => {
+    it("stamps last_updated_source = 'git-sync' on the subtree restore when the provenance arg is supplied", async () => {
+      const { repo, getUpdatePagesSql } = makeRepoCapturingSql();
+
+      await repo.restorePage('p1', 'ws-1', 'git-sync');
+
+      const update = getUpdatePagesSql();
+      expect(update).toBeDefined();
+      expect(update!.sql).toContain('"last_updated_source" =');
+      expect(update!.parameters).toContain('git-sync');
+      // Sanity: it is the restore UPDATE (clears deleted_at).
+      expect(update!.sql).toContain('"deleted_at" =');
+    });
+
+    it('OMITS last_updated_source from the restore when the provenance arg is undefined', async () => {
+      const { repo, getUpdatePagesSql } = makeRepoCapturingSql();
+
+      await repo.restorePage('p1', 'ws-1');
+
+      const update = getUpdatePagesSql();
+      expect(update).toBeDefined();
+      expect(update!.sql).not.toContain('last_updated_source');
+      expect(update!.parameters).not.toContain('git-sync');
+      expect(update!.sql).toContain('"deleted_at" =');
+    });
+  });
+});

apps/server/src/database/repos/page/page.repo.ts

@@ -294,6 +294,11 @@ export class PageRepo {
     pageId: string,
     deletedById: string,
     workspaceId: string,
+    // Optional provenance marker. When the soft-delete is driven by an automated
+    // data plane (e.g. git-sync), stamp `lastUpdatedSource` so the change-listener
+    // loop-guard recognizes it as its own write and does not schedule an echo
+    // cycle. Omitted for ordinary user deletes (column keeps its prior value).
+    lastUpdatedSource?: string,
   ): Promise<void> {
     const currentDate = new Date();
 
@@ -344,6 +349,7 @@ export class PageRepo {
           .set({
             deletedById: deletedById,
             deletedAt: currentDate,
+            ...(lastUpdatedSource ? { lastUpdatedSource } : {}),
           })
           .where('id', 'in', pageIds)
           .where('deletedAt', 'is', null)
@@ -374,7 +380,14 @@ export class PageRepo {
     }
   }
 
-  async restorePage(pageId: string, workspaceId: string): Promise<void> {
+  async restorePage(
+    pageId: string,
+    workspaceId: string,
+    // See removePage: stamp `lastUpdatedSource` for automated (git-sync) restores
+    // so the change-listener loop-guard skips the echo cycle. Omitted for
+    // ordinary user restores.
+    lastUpdatedSource?: string,
+  ): Promise<void> {
     // First, check if the page being restored has a deleted parent
     const pageToRestore = await this.db
       .selectFrom('pages')
@@ -425,7 +438,12 @@ export class PageRepo {
       // On restore, disarm the death timer: pulling a note out of trash means
       // "keep it". Otherwise a deadline now in the past would re-trash it on the
       // next cleanup sweep.
-      .set({ deletedById: null, deletedAt: null, temporaryExpiresAt: null })
+      .set({
+        deletedById: null,
+        deletedAt: null,
+        temporaryExpiresAt: null,
+        ...(lastUpdatedSource ? { lastUpdatedSource } : {}),
+      })
       .where('id', 'in', pageIds)
       .execute();
 

apps/server/src/database/repos/space/space.repo.spec.ts

@@ -0,0 +1,146 @@
+import {
+  Kysely,
+  DummyDriver,
+  PostgresAdapter,
+  PostgresIntrospector,
+  PostgresQueryCompiler,
+  CompiledQuery,
+} from 'kysely';
+import { SpaceRepo } from './space.repo';
+import type { KyselyDB } from '../../types/kysely.types';
+
+/**
+ * SQL-builder unit test for the jsonb-merge invariant of
+ * SpaceRepo.updateGitSyncSettings (review comment #694 / test-strategy item #6).
+ *
+ * The merge is RAW SQL, so a behavioural test would need a live Postgres — which
+ * is intentionally out of scope here (the reviewer's own §13.3 was deferred for
+ * the same reason). Instead we follow the existing repo-spec convention
+ * (ai-agent-roles.repo.spec.ts) of NOT executing: we compile the query with a
+ * DummyDriver Postgres dialect and assert the generated SQL preserves sibling
+ * keys. The structural invariant the SQL must encode:
+ *
+ *   settings  := COALESCE(settings, '{}') || jsonb_build_object('gitSync', ...)
+ *   gitSync   := COALESCE(settings->'gitSync', '{}') || jsonb_build_object(key, value)
+ *
+ * The OUTER `||` merges into the existing top-level `settings`, so a sibling
+ * top-level key (e.g. `sharing`) is preserved. The INNER COALESCE merges into
+ * the existing `gitSync` object, so a sibling key inside gitSync (e.g. `other`)
+ * is preserved. A naive `set settings = jsonb_build_object('gitSync', ...)`
+ * would clobber both — this test guards exactly that regression.
+ */
+describe('SpaceRepo.updateGitSyncSettings — jsonb merge SQL', () => {
+  // A real Kysely on the Postgres dialect, but with a DummyDriver: it compiles
+  // queries to real Postgres SQL without ever opening a connection.
+  function makeCompileOnlyDb() {
+    return new Kysely<any>({
+      dialect: {
+        createAdapter: () => new PostgresAdapter(),
+        createDriver: () => new DummyDriver(),
+        createIntrospector: (db) => new PostgresIntrospector(db),
+        createQueryCompiler: () => new PostgresQueryCompiler(),
+      },
+    });
+  }
+
+  // Build the repo over the compile-only db. The repo terminates the query with
+  // `.executeTakeFirst()`, so we wrap every kysely builder in a Proxy: when the
+  // repo finally calls `executeTakeFirst`, we `.compile()` that same builder
+  // ourselves to capture the exact SQL it was about to run, then delegate.
+  function makeRepoCapturingSql() {
+    const db = makeCompileOnlyDb();
+    let captured: CompiledQuery | undefined;
+
+    // kysely builders are immutable — each .set()/.where()/.returningAll()
+    // returns a NEW builder — so re-wrap any chainable result.
+    const wrap = (b: any): any =>
+      new Proxy(b, {
+        get(target, prop, receiver) {
+          const value = Reflect.get(target, prop, receiver);
+          if (typeof value !== 'function') return value;
+          return (...callArgs: unknown[]) => {
+            // Capture the SQL at the terminal execute call.
+            if (
+              (prop === 'executeTakeFirst' || prop === 'execute') &&
+              typeof target.compile === 'function'
+            ) {
+              captured = target.compile();
+            }
+            const result = value.apply(target, callArgs);
+            if (
+              result &&
+              typeof result === 'object' &&
+              typeof (result as any).compile === 'function'
+            ) {
+              return wrap(result);
+            }
+            return result;
+          };
+        },
+      });
+
+    const originalUpdateTable = db.updateTable.bind(db);
+    jest
+      .spyOn(db, 'updateTable')
+      .mockImplementation((...args: Parameters<typeof originalUpdateTable>) =>
+        wrap(originalUpdateTable(...args)),
+      );
+
+    const repo = new SpaceRepo(db as unknown as KyselyDB, {} as any);
+    return { repo, getCaptured: () => captured };
+  }
+
+  it("compiles a jsonb merge that preserves sibling top-level and gitSync keys", async () => {
+    const { repo, getCaptured } = makeRepoCapturingSql();
+
+    // DummyDriver yields no rows; executeTakeFirst resolves to undefined. The
+    // SQL is fully compiled by then, which is all we assert.
+    await repo.updateGitSyncSettings('space-1', 'ws-1', 'enabled', true);
+
+    const compiled = getCaptured();
+    expect(compiled).toBeDefined();
+    // The raw SQL template carries newlines/indentation; collapse whitespace so
+    // the structural assertions are not coupled to source formatting.
+    const sql = compiled!.sql.replace(/\s+/g, ' ');
+
+    // OUTER merge into the existing settings object -> sibling top-level keys
+    // (e.g. `sharing`) survive (NOT a bare jsonb_build_object assignment).
+    expect(sql).toContain(`set "settings" = COALESCE(settings, '{}'::jsonb) ||`);
+    // INNER merge into the existing gitSync object -> sibling gitSync keys
+    // (e.g. `other`) survive.
+    expect(sql).toContain(
+      `jsonb_build_object('gitSync', COALESCE(settings->'gitSync', '{}'::jsonb) ||`,
+    );
+    // The pref key is set via jsonb_build_object on the inner object, with the
+    // key as a BOUND, ::text-cast PARAMETER (not sql.raw) — security fix #5.
+    expect(sql).toMatch(/jsonb_build_object\(\$\d+::text,/);
+    // Scoped to the row + workspace.
+    expect(sql).toContain(`where "id" =`);
+    expect(sql).toContain(`and "workspaceId" =`);
+
+    // Sanity: this is NOT a clobbering assignment (no top-level
+    // `set "settings" = jsonb_build_object(` without the COALESCE/merge).
+    expect(sql).not.toContain(`set "settings" = jsonb_build_object(`);
+
+    // The pref VALUE stays inlined via sql.lit, but the KEY is now a bound
+    // parameter, so id + workspaceId + the key are all bound (updatedAt is a Date).
+    expect(compiled!.parameters).toContain('space-1');
+    expect(compiled!.parameters).toContain('ws-1');
+    expect(compiled!.parameters).toContain('enabled');
+  });
+
+  it('binds the prefKey as a ::text parameter (no sql.raw splice) and inlines prefValue via sql.lit', async () => {
+    const { repo, getCaptured } = makeRepoCapturingSql();
+
+    await repo.updateGitSyncSettings('space-1', 'ws-1', 'enabled', false);
+
+    const compiled = getCaptured()!;
+    const sql = compiled.sql.replace(/\s+/g, ' ');
+    // The key is a bound `$N::text` parameter; the value is the sql.lit literal.
+    expect(sql).toMatch(/jsonb_build_object\(\$\d+::text, false\)/);
+    // The literal key must NOT be spliced into the statement text (the footgun).
+    expect(sql).not.toContain(`'enabled'`);
+    // The key rides as a bound parameter instead.
+    expect(compiled.parameters).toContain('enabled');
+  });
+});

apps/server/src/database/repos/space/space.repo.ts

@@ -111,6 +111,34 @@ export class SpaceRepo {
       .executeTakeFirst();
   }
 
+  async updateGitSyncSettings(
+    spaceId: string,
+    workspaceId: string,
+    prefKey: string,
+    prefValue: string | boolean,
+    trx?: KyselyTransaction,
+  ) {
+    const db = dbOrTx(this.db, trx);
+    return db
+      .updateTable('spaces')
+      .set({
+        // The jsonb key is a BOUND PARAMETER (`${prefKey}::text`), not
+        // `sql.raw(prefKey)`. The callers here only ever pass the literals
+        // 'enabled' / 'autoMergeConflicts', but sql.raw would splice the string
+        // straight into the statement — a latent SQL-injection footgun the moment
+        // a future caller passes a request-derived key. Parameterizing closes it
+        // with no behaviour change for the current literal callers.
+        settings: sql`COALESCE(settings, '{}'::jsonb)
+          || jsonb_build_object('gitSync', COALESCE(settings->'gitSync', '{}'::jsonb)
+          || jsonb_build_object(${prefKey}::text, ${sql.lit(prefValue)}))`,
+        updatedAt: new Date(),
+      })
+      .where('id', '=', spaceId)
+      .where('workspaceId', '=', workspaceId)
+      .returningAll()
+      .executeTakeFirst();
+  }
+
   async updateCommentSettings(
     spaceId: string,
     workspaceId: string,

apps/server/src/integrations/environment/environment.service.spec.ts

@@ -14,4 +14,162 @@ describe('EnvironmentService', () => {
   it('should be defined', () => {
     expect(service).toBeDefined();
   });
+
+  describe('getGitSyncPollIntervalMs', () => {
+    const withEnv = (value?: string) =>
+      new EnvironmentService({
+        get: (_key: string, fallback?: string) => value ?? fallback,
+      } as any);
+
+    it('defaults to 15000 when unset', () => {
+      expect(withEnv().getGitSyncPollIntervalMs()).toBe(15000);
+    });
+
+    it('parses a valid positive int', () => {
+      expect(withEnv('30000').getGitSyncPollIntervalMs()).toBe(30000);
+    });
+
+    it('falls back to 15000 for non-positive or unparseable values', () => {
+      expect(withEnv('0').getGitSyncPollIntervalMs()).toBe(15000);
+      expect(withEnv('-100').getGitSyncPollIntervalMs()).toBe(15000);
+      expect(withEnv('not-a-number').getGitSyncPollIntervalMs()).toBe(15000);
+    });
+  });
+
+  describe('getGitSyncDebounceMs', () => {
+    const withEnv = (value?: string) =>
+      new EnvironmentService({
+        get: (_key: string, fallback?: string) => value ?? fallback,
+      } as any);
+
+    it('defaults to 2000 when unset', () => {
+      expect(withEnv().getGitSyncDebounceMs()).toBe(2000);
+    });
+
+    it('parses a valid positive int', () => {
+      expect(withEnv('500').getGitSyncDebounceMs()).toBe(500);
+    });
+
+    it('falls back to 2000 for non-positive or unparseable values', () => {
+      expect(withEnv('0').getGitSyncDebounceMs()).toBe(2000);
+      expect(withEnv('-5').getGitSyncDebounceMs()).toBe(2000);
+      expect(withEnv('not-a-number').getGitSyncDebounceMs()).toBe(2000);
+    });
+  });
+
+  // getGitSyncDataDir reads two distinct keys (GIT_SYNC_DATA_DIR and DATA_DIR),
+  // so this builder maps each key to a supplied value (and honours the fallback
+  // the getter passes for DATA_DIR's `|| './data'`).
+  describe('getGitSyncDataDir', () => {
+    const withEnv = (values: Record<string, string | undefined>) =>
+      new EnvironmentService({
+        get: (key: string, fallback?: string) => values[key] ?? fallback,
+      } as any);
+
+    it("defaults to './data/git-sync' when neither key is set", () => {
+      expect(withEnv({}).getGitSyncDataDir()).toBe('./data/git-sync');
+    });
+
+    it('derives from DATA_DIR with the /git-sync suffix', () => {
+      expect(
+        withEnv({ DATA_DIR: '/var/lib/docmost' }).getGitSyncDataDir(),
+      ).toBe('/var/lib/docmost/git-sync');
+    });
+
+    it('strips trailing slashes from DATA_DIR before appending', () => {
+      expect(
+        withEnv({ DATA_DIR: '/var/lib/docmost///' }).getGitSyncDataDir(),
+      ).toBe('/var/lib/docmost/git-sync');
+    });
+
+    it('lets an explicit GIT_SYNC_DATA_DIR override the DATA_DIR derivation', () => {
+      expect(
+        withEnv({
+          GIT_SYNC_DATA_DIR: '/custom/vault',
+          DATA_DIR: '/var/lib/docmost',
+        }).getGitSyncDataDir(),
+      ).toBe('/custom/vault');
+    });
+
+    it('returns the explicit override verbatim (no /git-sync suffix, no slash strip)', () => {
+      expect(
+        withEnv({ GIT_SYNC_DATA_DIR: '/custom/vault/' }).getGitSyncDataDir(),
+      ).toBe('/custom/vault/');
+    });
+  });
+
+  // isGitSyncEnabled is the `.toLowerCase() === 'true'` contract: only a
+  // case-insensitive "true" enables it; everything else (unset, "false",
+  // garbage) is false.
+  describe('isGitSyncEnabled', () => {
+    const withEnv = (value?: string) =>
+      new EnvironmentService({
+        get: (_key: string, fallback?: string) => value ?? fallback,
+      } as any);
+
+    it('is true for "true" and "TRUE" (case-insensitive)', () => {
+      expect(withEnv('true').isGitSyncEnabled()).toBe(true);
+      expect(withEnv('TRUE').isGitSyncEnabled()).toBe(true);
+    });
+
+    it('is false when unset (defaults to "false")', () => {
+      expect(withEnv().isGitSyncEnabled()).toBe(false);
+    });
+
+    it('is false for "false" and garbage values', () => {
+      expect(withEnv('false').isGitSyncEnabled()).toBe(false);
+      expect(withEnv('maybe').isGitSyncEnabled()).toBe(false);
+      expect(withEnv('1').isGitSyncEnabled()).toBe(false);
+    });
+  });
+
+  // isGitSyncHttpEnabled is the master gate of the /git smart-HTTP trust boundary.
+  // When GIT_SYNC_HTTP_ENABLED is UNSET it FALLS BACK to isGitSyncEnabled(); when
+  // set it is honored verbatim ('true' -> on, anything else -> off). The fallback
+  // (default) branch is what these tests pin.
+  describe('isGitSyncHttpEnabled', () => {
+    const withEnv = (values: Record<string, string | undefined>) =>
+      new EnvironmentService({
+        get: (key: string, fallback?: string) => values[key] ?? fallback,
+      } as any);
+
+    it('DEFAULT branch: unset -> falls back to isGitSyncEnabled() === true', () => {
+      expect(
+        withEnv({ GIT_SYNC_ENABLED: 'true' }).isGitSyncHttpEnabled(),
+      ).toBe(true);
+    });
+
+    it('DEFAULT branch: unset -> falls back to isGitSyncEnabled() === false', () => {
+      // Neither key set: the fallback resolves to isGitSyncEnabled() which is
+      // false by default.
+      expect(withEnv({}).isGitSyncHttpEnabled()).toBe(false);
+      expect(
+        withEnv({ GIT_SYNC_ENABLED: 'false' }).isGitSyncHttpEnabled(),
+      ).toBe(false);
+    });
+
+    it('explicit "true" enables the host regardless of GIT_SYNC_ENABLED', () => {
+      expect(
+        withEnv({
+          GIT_SYNC_HTTP_ENABLED: 'true',
+          GIT_SYNC_ENABLED: 'false',
+        }).isGitSyncHttpEnabled(),
+      ).toBe(true);
+    });
+
+    it('explicit non-"true" disables the host even when sync is enabled', () => {
+      expect(
+        withEnv({
+          GIT_SYNC_HTTP_ENABLED: 'false',
+          GIT_SYNC_ENABLED: 'true',
+        }).isGitSyncHttpEnabled(),
+      ).toBe(false);
+      expect(
+        withEnv({
+          GIT_SYNC_HTTP_ENABLED: 'maybe',
+          GIT_SYNC_ENABLED: 'true',
+        }).isGitSyncHttpEnabled(),
+      ).toBe(false);
+    });
+  });
 });

apps/server/src/integrations/environment/environment.service.ts

@@ -332,4 +332,97 @@ export class EnvironmentService {
       .map((o) => o.trim())
       .filter(Boolean);
   }
+
+  // --- git-sync (issue #194 §7.2) -------------------------------------------------
+
+  /** Global master switch for the git-sync control plane (default false). */
+  isGitSyncEnabled(): boolean {
+    return (
+      this.configService.get<string>('GIT_SYNC_ENABLED', 'false').toLowerCase() ===
+      'true'
+    );
+  }
+
+  /**
+   * Whether gitmost serves the per-space vaults over smart-HTTP (the /git host).
+   * When GIT_SYNC_HTTP_ENABLED is UNSET it DEFAULTS to isGitSyncEnabled() — so
+   * enabling sync also enables the host unless explicitly disabled. When set, it
+   * is honored verbatim ('true' -> on, anything else -> off).
+   */
+  isGitSyncHttpEnabled(): boolean {
+    const raw = this.configService.get<string>('GIT_SYNC_HTTP_ENABLED');
+    if (raw === undefined) return this.isGitSyncEnabled();
+    return raw.toLowerCase() === 'true';
+  }
+
+  /**
+   * Root directory holding the per-space vault repos. Defaults to
+   * `<DATA_DIR or ./data>/git-sync`. `DATA_DIR` is read directly (no dedicated
+   * getter exists in this codebase) so the vault root tracks the data volume.
+   */
+  getGitSyncDataDir(): string {
+    const explicit = this.configService.get<string>('GIT_SYNC_DATA_DIR');
+    if (explicit) return explicit;
+    const dataDir = this.configService.get<string>('DATA_DIR') || './data';
+    return `${dataDir.replace(/\/+$/, '')}/git-sync`;
+  }
+
+  /**
+   * Optional remote template, e.g. `git@host:vault-{spaceId}.git` (`{spaceId}` is
+   * substituted per-space in the orchestrator). SCAFFOLDING for the deferred
+   * remote-push feature: the vendored engine has no remote-push path yet (SPEC
+   * §7), so this value is currently inert — kept so the wiring is ready when the
+   * engine grows a push path.
+   */
+  getGitSyncRemoteTemplate(): string | undefined {
+    return this.configService.get<string>('GIT_SYNC_REMOTE_TEMPLATE');
+  }
+
+  /**
+   * Poll-safety interval in ms (default 15000). A NaN / non-positive value falls
+   * back to the default so a bad override can never disable or zero the poll loop.
+   */
+  getGitSyncPollIntervalMs(): number {
+    const parsed = parseInt(
+      this.configService.get<string>('GIT_SYNC_POLL_INTERVAL_MS', '15000'),
+      10,
+    );
+    return Number.isFinite(parsed) && parsed > 0 ? parsed : 15000;
+  }
+
+  /**
+   * Spawned `git http-backend` watchdog timeout in ms (default 120000). Bounds a
+   * single smart-HTTP request so a stalled `git-receive-pack` cannot hold the
+   * per-space lock forever (the child is killed and a 500 sent on expiry). A NaN /
+   * non-positive value falls back to the default so a bad override can never
+   * disable the watchdog.
+   */
+  getGitSyncBackendTimeoutMs(): number {
+    const v = parseInt(
+      this.configService.get<string>('GIT_SYNC_BACKEND_TIMEOUT_MS', '120000'),
+      10,
+    );
+    return Number.isFinite(v) && v > 0 ? v : 120000;
+  }
+
+  /**
+   * Event debounce window in ms (default 2000). A NaN / non-positive value falls
+   * back to the default so a bad override can never disable the debounce.
+   */
+  getGitSyncDebounceMs(): number {
+    const parsed = parseInt(
+      this.configService.get<string>('GIT_SYNC_DEBOUNCE_MS', '2000'),
+      10,
+    );
+    return Number.isFinite(parsed) && parsed > 0 ? parsed : 2000;
+  }
+
+
+  /**
+   * The service user id git-sync writes are attributed to. Required when sync is
+   * enabled (validated in environment.validation.ts); optional otherwise.
+   */
+  getGitSyncServiceUserId(): string | undefined {
+    return this.configService.get<string>('GIT_SYNC_SERVICE_USER_ID');
+  }
 }

apps/server/src/integrations/environment/environment.validation.spec.ts

@@ -0,0 +1,74 @@
+import { plainToInstance } from 'class-transformer';
+import { validateSync } from 'class-validator';
+import { EnvironmentVariables } from './environment.validation';
+
+/**
+ * Validation-layer coverage for the git-sync env contract (test-strategy Module
+ * 4 / item #4). We drive the decorated class with `validateSync` directly — the
+ * exported `validate()` helper calls `process.exit(1)` on failure and so cannot
+ * be asserted in-process. We only assert the git-sync rules, providing the
+ * minimal always-required fields so unrelated validators do not add noise.
+ */
+describe('EnvironmentVariables — git-sync validation', () => {
+  // A baseline config that satisfies the unconditionally-required fields
+  // (DATABASE_URL, REDIS_URL, APP_SECRET) so the only errors we ever see come
+  // from the git-sync rules under test.
+  const baseConfig = {
+    DATABASE_URL: 'postgres://user:pass@localhost:5432/docmost',
+    REDIS_URL: 'redis://localhost:6379',
+    APP_SECRET: 'x'.repeat(32),
+  };
+
+  const validate = (extra: Record<string, unknown>) => {
+    const instance = plainToInstance(EnvironmentVariables, {
+      ...baseConfig,
+      ...extra,
+    });
+    return validateSync(instance);
+  };
+
+  const errorFor = (errors: ReturnType<typeof validateSync>, property: string) =>
+    errors.find((e) => e.property === property);
+
+  it('flags GIT_SYNC_SERVICE_USER_ID when GIT_SYNC_ENABLED="true" and the id is absent', () => {
+    const errors = validate({ GIT_SYNC_ENABLED: 'true' });
+
+    const err = errorFor(errors, 'GIT_SYNC_SERVICE_USER_ID');
+    expect(err).toBeDefined();
+    // @IsNotEmpty is the failing constraint (sync is on but no attributable
+    // author was configured).
+    expect(err?.constraints).toHaveProperty('isNotEmpty');
+  });
+
+  it('accepts GIT_SYNC_ENABLED="true" once GIT_SYNC_SERVICE_USER_ID is present', () => {
+    const errors = validate({
+      GIT_SYNC_ENABLED: 'true',
+      GIT_SYNC_SERVICE_USER_ID: 'service-user-1',
+    });
+
+    expect(errorFor(errors, 'GIT_SYNC_SERVICE_USER_ID')).toBeUndefined();
+  });
+
+  it('does not require the service user id when git-sync is disabled (unset)', () => {
+    const errors = validate({});
+
+    // The @ValidateIf gate (GIT_SYNC_ENABLED === "true") is not met, so the
+    // required-if-enabled rule is skipped entirely.
+    expect(errorFor(errors, 'GIT_SYNC_SERVICE_USER_ID')).toBeUndefined();
+  });
+
+  it('does not require the service user id when git-sync is explicitly "false"', () => {
+    const errors = validate({ GIT_SYNC_ENABLED: 'false' });
+
+    expect(errorFor(errors, 'GIT_SYNC_SERVICE_USER_ID')).toBeUndefined();
+    expect(errorFor(errors, 'GIT_SYNC_ENABLED')).toBeUndefined();
+  });
+
+  it('rejects a GIT_SYNC_ENABLED value outside the {true,false} set via @IsIn', () => {
+    const errors = validate({ GIT_SYNC_ENABLED: 'maybe' });
+
+    const err = errorFor(errors, 'GIT_SYNC_ENABLED');
+    expect(err).toBeDefined();
+    expect(err?.constraints).toHaveProperty('isIn');
+  });
+});

apps/server/src/integrations/environment/environment.validation.ts

@@ -170,6 +170,55 @@ export class EnvironmentVariables {
     },
   )
   CLICKHOUSE_URL: string;
+
+  // --- git-sync (issue #194 §7.2) — all OPTIONAL. The master switch defaults off; a
+  // required-if-enabled service user id is validated only when sync is on. ---
+
+  @IsOptional()
+  @IsIn(['true', 'false'])
+  @IsString()
+  GIT_SYNC_ENABLED: string;
+
+  // Whether to serve the per-space vaults over smart-HTTP (the /git host).
+  // When unset, defaults to GIT_SYNC_ENABLED (see isGitSyncHttpEnabled).
+  @IsOptional()
+  @IsIn(['true', 'false'])
+  @IsString()
+  GIT_SYNC_HTTP_ENABLED: string;
+
+  @IsOptional()
+  @IsString()
+  GIT_SYNC_DATA_DIR: string;
+
+  // SCAFFOLDING for the deferred remote-push feature: the vendored engine does
+  // not consume gitRemote yet (SPEC §7), so this is currently inert — validated
+  // here so the wiring is ready when remote push lands.
+  @IsOptional()
+  @IsString()
+  GIT_SYNC_REMOTE_TEMPLATE: string;
+
+  @IsOptional()
+  @IsString()
+  GIT_SYNC_POLL_INTERVAL_MS: string;
+
+  @IsOptional()
+  @IsString()
+  GIT_SYNC_DEBOUNCE_MS: string;
+
+  // Watchdog timeout (ms) for the spawned `git http-backend` process (default
+  // 120000): a stalled receive-pack is killed so it cannot hold the per-space
+  // lock forever. Optional int (validated as a string env).
+  @IsOptional()
+  @IsString()
+  GIT_SYNC_BACKEND_TIMEOUT_MS: string;
+
+
+  // Required when git-sync is enabled: the service user create/move/rename/delete
+  // are attributed to (issue #194 §7.2). Optional otherwise.
+  @ValidateIf((obj) => obj.GIT_SYNC_ENABLED === 'true')
+  @IsNotEmpty()
+  @IsString()
+  GIT_SYNC_SERVICE_USER_ID: string;
 }
 
 export function validate(config: Record<string, any>) {

apps/server/src/integrations/export/utils.spec.ts

@@ -146,6 +146,27 @@ describe('getInternalLinkPageName', () => {
     expect(getInternalLinkPageName('Parent/My%20Page.md')).toBe('My Page');
   });
 
+  it('keeps the full basename when the path has no extension (#204)', () => {
+    // An extensionless link target must NOT be stripped to an empty string —
+    // there is no extension to drop. Previously `.split('.').slice(0,-1)`
+    // collapsed "My Page" to "" and the internal link rendered with no text.
+    expect(getInternalLinkPageName('Parent/My%20Page')).toBe('My Page');
+    expect(getInternalLinkPageName('Just A Name')).toBe('Just A Name');
+  });
+
+  it('preserves dots in a dotted name that has a real extension (#204)', () => {
+    // "v1.2.md" -> "v1.2": only the final ".md" segment is the extension.
+    expect(getInternalLinkPageName('docs/v1.2.md')).toBe('v1.2');
+  });
+
+  it('documents current behavior: a leading-dot name collapses to empty text', () => {
+    // ".gitignore" -> base ".gitignore", parts ["", "gitignore"]: the leading
+    // dot is treated as a (empty) name + extension, so the name drops to "".
+    // Same bug class as #204, but unreachable via the sole caller (page titles
+    // never start with a dot), so we only pin the behavior — not fix it.
+    expect(getInternalLinkPageName('.gitignore')).toBe('');
+  });
+
   it('falls back to the raw name without throwing on malformed encoding', () => {
     // "%E0%A4" is an incomplete escape; decodeURIComponent throws and the
     // helper returns the raw (still-encoded) name.

apps/server/src/integrations/export/utils.ts

@@ -106,7 +106,16 @@ export function replaceInternalLinks(
 }
 
 export function getInternalLinkPageName(path: string, currentFilePath?: string): string {
-  const name = path?.split('/').pop().split('.').slice(0, -1).join('.');
+  // Strip a trailing file extension from the basename, but only when there IS
+  // one: an extensionless link target (e.g. "My Page") has no extension to drop,
+  // so `split('.').slice(0,-1)` would otherwise collapse it to an empty string,
+  // producing an internal link with no visible text (#204 export bug). The last
+  // dot-segment is always treated as an extension and dropped whenever there is
+  // more than one segment, so dots are preserved only in multi-segment names
+  // like `v1.2.md` -> `v1.2`; a bare `v1.2` becomes `v1`.
+  const base = path?.split('/').pop();
+  const parts = base?.split('.');
+  const name = parts && parts.length > 1 ? parts.slice(0, -1).join('.') : base;
   try {
     return decodeURIComponent(name);
   } catch (err) {

apps/server/src/integrations/git-sync/git-sync.constants.ts

@@ -0,0 +1,62 @@
+/**
+ * Git-sync control-plane constants.
+ *
+ * Event/job names are REUSED from the shared event contract (event.contants.ts)
+ * so the listener subscribes to the exact names the rest of the server emits —
+ * never a string literal that could drift. The Redis lock-key prefix + TTLs back
+ * the single-writer leader lock (§9); the debounce default backs the per-space
+ * event coalescing (§10).
+ */
+import { EventName } from '../../common/events/event.contants';
+
+/**
+ * The page lifecycle events the git-sync listener reacts to. A change
+ * to any of these in an enabled space schedules a debounced sync cycle.
+ *   - PAGE_CREATED / PAGE_UPDATED / PAGE_MOVED — structural + content edits;
+ *   - PAGE_SOFT_DELETED / PAGE_RESTORED — Trash transitions (deletes are soft);
+ *   - PAGE_MOVED_TO_SPACE — cross-space move (cross-repo).
+ *
+ * NOTE: body edits arrive via PAGE_UPDATED (emitted from persistence.extension),
+ * NOT via EventName.PAGE_CONTENT_UPDATED — that name is a BullMQ queue-job name,
+ * not an EventEmitter2 event, so @OnEvent would never fire for it.
+ */
+export const GIT_SYNC_PAGE_EVENTS = [
+  EventName.PAGE_CREATED,
+  EventName.PAGE_UPDATED,
+  EventName.PAGE_MOVED,
+  EventName.PAGE_MOVED_TO_SPACE,
+  EventName.PAGE_SOFT_DELETED,
+  EventName.PAGE_RESTORED,
+] as const;
+
+/** Redis key prefix for the per-space leader lock. */
+export const GIT_SYNC_LOCK_PREFIX = 'git-sync:lock:';
+
+/**
+ * Leader-lock TTL (ms). Must exceed the maximum expected cycle duration so the
+ * lock is not lost mid-cycle; on a crash it expires on its own. The
+ * in-process mutex (orchestrator) prevents overlapping cycles on one instance,
+ * and the Redis lock prevents two instances racing the same space.
+ */
+export const GIT_SYNC_LOCK_TTL_MS = 5 * 60 * 1000;
+
+/**
+ * Bounded retry budget for ACQUIRING the per-space lock on the PUSH (external
+ * receive-pack) path. The poll cycle holds the single-writer lock while it
+ * processes a whole space, so a legitimate `git push` that arrives during a
+ * cycle would otherwise IMMEDIATELY 503 (GitSyncLockHeldError) even though the
+ * cycle is about to release the lock in well under a second for most spaces.
+ * Under continuous polling that made a majority of pushes 503 non-
+ * deterministically. So the push path retries the acquire with a small capped
+ * backoff for up to ~`TOTAL_MS` BEFORE giving up — a transient overlap with a
+ * cycle no longer fails the push, while a genuinely stuck/long cycle still
+ * surfaces a 503 after the bound (git then retries the whole push, which is
+ * safe: the receive-pack only runs ONCE the lock is held, so a 503 never leaves
+ * a half-applied ref). The POLL cycle itself does NOT retry (it just skips and
+ * the next tick reconciles), so this is push-only — the smaller blast radius.
+ */
+export const GIT_SYNC_PUSH_LOCK_RETRY_TOTAL_MS = 5_000;
+/** First backoff between push lock-acquire attempts (ms); doubles, capped. */
+export const GIT_SYNC_PUSH_LOCK_RETRY_BASE_MS = 100;
+/** Cap on the per-attempt push lock-acquire backoff (ms). */
+export const GIT_SYNC_PUSH_LOCK_RETRY_MAX_MS = 500;

apps/server/src/integrations/git-sync/git-sync.controller.spec.ts

@@ -0,0 +1,138 @@
+// Unit tests for the ops/testing controller. The orchestrator, env,
+// and the workspace-ability factory are hand-built mocks. We assert the admin
+// guard (non-admin -> ForbiddenException, no orchestrator call), that trigger
+// uses the workspace from request context (never the body), and that status
+// returns the env-derived object.
+import { ForbiddenException, NotFoundException } from '@nestjs/common';
+import {
+  WorkspaceCaslAction,
+  WorkspaceCaslSubject,
+} from '../../core/casl/interfaces/workspace-ability.type';
+import { GitSyncController } from './git-sync.controller';
+
+type AnyMock = jest.Mock;
+
+interface Built {
+  controller: GitSyncController;
+  orchestrator: { runOnce: AnyMock };
+  env: Record<string, AnyMock>;
+  workspaceAbility: { createForUser: AnyMock };
+  ability: { cannot: AnyMock };
+  spaceRepo: { findById: AnyMock };
+}
+
+function build(opts: { cannot?: boolean; spaceFound?: boolean } = {}): Built {
+  const { cannot = false, spaceFound = true } = opts;
+  const ability = { cannot: jest.fn(() => cannot) };
+  const workspaceAbility = { createForUser: jest.fn(() => ability) };
+
+  const orchestrator = {
+    runOnce: jest.fn(async () => ({ spaceId: 'space-1', ran: true })),
+  };
+  const env: Record<string, AnyMock> = {
+    isGitSyncEnabled: jest.fn(() => true),
+    getGitSyncDataDir: jest.fn(() => '/vaults'),
+    getGitSyncPollIntervalMs: jest.fn(() => 15000),
+    getGitSyncDebounceMs: jest.fn(() => 2000),
+    getGitSyncServiceUserId: jest.fn(() => 'svc-user'),
+  };
+  const spaceRepo = {
+    findById: jest.fn(async () => (spaceFound ? { id: 'space-1' } : undefined)),
+  };
+
+  const controller = new GitSyncController(
+    orchestrator as any,
+    env as any,
+    workspaceAbility as any,
+    spaceRepo as any,
+  );
+  return { controller, orchestrator, env, workspaceAbility, ability, spaceRepo };
+}
+
+const USER = { id: 'user-1' } as any;
+const WORKSPACE = { id: 'ctx-ws' } as any;
+
+beforeEach(() => {
+  jest.clearAllMocks();
+});
+
+describe('GitSyncController', () => {
+  describe('trigger', () => {
+    it('blocks a non-admin: throws ForbiddenException and never calls runOnce', async () => {
+      const { controller, orchestrator, ability } = build({ cannot: true });
+
+      await expect(
+        controller.trigger({ spaceId: 'space-1' } as any, USER, WORKSPACE),
+      ).rejects.toBeInstanceOf(ForbiddenException);
+
+      expect(ability.cannot).toHaveBeenCalledWith(
+        WorkspaceCaslAction.Manage,
+        WorkspaceCaslSubject.Settings,
+      );
+      expect(orchestrator.runOnce).not.toHaveBeenCalled();
+    });
+
+    it('admin: calls runOnce(dto.spaceId, workspace.id) using the workspace from context', async () => {
+      const { controller, orchestrator, spaceRepo } = build({ cannot: false });
+
+      // The body carries an attacker-controlled workspaceId that must be ignored.
+      const res = await controller.trigger(
+        { spaceId: 'space-1', workspaceId: 'evil-ws' } as any,
+        USER,
+        WORKSPACE,
+      );
+
+      // The space is resolved workspace-scoped (context workspace, not the body).
+      expect(spaceRepo.findById).toHaveBeenCalledWith('space-1', 'ctx-ws');
+      expect(orchestrator.runOnce).toHaveBeenCalledWith('space-1', 'ctx-ws');
+      expect(res).toEqual({ spaceId: 'space-1', ran: true });
+    });
+
+    it('admin: 404s a spaceId that is not in the workspace and never calls runOnce', async () => {
+      // A foreign/non-existent space must be rejected BEFORE buildSettings runs
+      // (which would otherwise create an empty per-space vault directory).
+      const { controller, orchestrator, spaceRepo } = build({
+        cannot: false,
+        spaceFound: false,
+      });
+
+      await expect(
+        controller.trigger({ spaceId: 'foreign' } as any, USER, WORKSPACE),
+      ).rejects.toBeInstanceOf(NotFoundException);
+
+      expect(spaceRepo.findById).toHaveBeenCalledWith('foreign', 'ctx-ws');
+      expect(orchestrator.runOnce).not.toHaveBeenCalled();
+    });
+  });
+
+  describe('status', () => {
+    it('blocks a non-admin: throws ForbiddenException and never reads env', async () => {
+      const { controller, env, ability } = build({ cannot: true });
+
+      await expect(controller.status(USER, WORKSPACE)).rejects.toBeInstanceOf(
+        ForbiddenException,
+      );
+
+      expect(ability.cannot).toHaveBeenCalledWith(
+        WorkspaceCaslAction.Manage,
+        WorkspaceCaslSubject.Settings,
+      );
+      // The admin guard short-circuits before the env-derived status is built.
+      expect(env.isGitSyncEnabled).not.toHaveBeenCalled();
+    });
+
+    it('admin: returns the env-derived status object', async () => {
+      const { controller } = build({ cannot: false });
+
+      const res = await controller.status(USER, WORKSPACE);
+
+      expect(res).toEqual({
+        enabled: true,
+        dataDir: '/vaults',
+        pollIntervalMs: 15000,
+        debounceMs: 2000,
+        serviceUserConfigured: true,
+      });
+    });
+  });
+});

apps/server/src/integrations/git-sync/git-sync.controller.ts

@@ -0,0 +1,109 @@
+import {
+  Body,
+  Controller,
+  ForbiddenException,
+  HttpCode,
+  HttpStatus,
+  NotFoundException,
+  Post,
+  Get,
+  UseGuards,
+} from '@nestjs/common';
+import { JwtAuthGuard } from '../../common/guards/jwt-auth.guard';
+import { AuthUser } from '../../common/decorators/auth-user.decorator';
+import { AuthWorkspace } from '../../common/decorators/auth-workspace.decorator';
+import { User, Workspace } from '@docmost/db/types/entity.types';
+import { SpaceRepo } from '@docmost/db/repos/space/space.repo';
+import WorkspaceAbilityFactory from '../../core/casl/abilities/workspace-ability.factory';
+import {
+  WorkspaceCaslAction,
+  WorkspaceCaslSubject,
+} from '../../core/casl/interfaces/workspace-ability.type';
+import { EnvironmentService } from '../environment/environment.service';
+import { IsUUID } from 'class-validator';
+import {
+  GitSyncOrchestrator,
+  GitSyncRunStatus,
+} from './services/git-sync.orchestrator';
+
+/** Body for the manual one-shot trigger. */
+class TriggerGitSyncDto {
+  // The global ValidationPipe runs with whitelist:true, which STRIPS any field
+  // lacking a validation decorator — without this @IsUUID the spaceId would be
+  // dropped and arrive as undefined.
+  @IsUUID()
+  spaceId: string;
+}
+
+/**
+ * Ops/testing endpoints for the git-sync control plane. Admin-guarded
+ * (workspace Manage/Settings, mirroring WorkspaceController) so only workspace
+ * admins can force a cycle. Mounted under the global `/api` prefix:
+ *   - POST /api/git-sync/trigger { spaceId } — run one cycle now (await result),
+ *   - GET  /api/git-sync/status — report whether sync is enabled + config.
+ */
+@UseGuards(JwtAuthGuard)
+@Controller('git-sync')
+export class GitSyncController {
+  constructor(
+    private readonly orchestrator: GitSyncOrchestrator,
+    private readonly environmentService: EnvironmentService,
+    private readonly workspaceAbility: WorkspaceAbilityFactory,
+    private readonly spaceRepo: SpaceRepo,
+  ) {}
+
+  /** Throw unless the caller is a workspace admin (Manage Settings). */
+  private assertAdmin(user: User, workspace: Workspace): void {
+    const ability = this.workspaceAbility.createForUser(user, workspace);
+    if (
+      ability.cannot(WorkspaceCaslAction.Manage, WorkspaceCaslSubject.Settings)
+    ) {
+      throw new ForbiddenException();
+    }
+  }
+
+  @HttpCode(HttpStatus.OK)
+  @Post('trigger')
+  async trigger(
+    @Body() dto: TriggerGitSyncDto,
+    @AuthUser() user: User,
+    @AuthWorkspace() workspace: Workspace,
+  ): Promise<GitSyncRunStatus> {
+    this.assertAdmin(user, workspace);
+    // Verify the client-supplied spaceId BELONGS to this workspace before doing
+    // any work (review): without this, `runOnce` -> `buildSettings` reads the
+    // raw `spaces` row and creates an empty per-space vault directory for a
+    // foreign/non-existent space before the content read finally 404s. Resolve
+    // it workspace-scoped and 404 early.
+    const space = await this.spaceRepo.findById(dto.spaceId, workspace.id);
+    if (!space) {
+      throw new NotFoundException('Space not found');
+    }
+    // Use the workspace from the request context (never client-supplied).
+    return this.orchestrator.runOnce(dto.spaceId, workspace.id);
+  }
+
+  @HttpCode(HttpStatus.OK)
+  @Get('status')
+  async status(
+    @AuthUser() user: User,
+    @AuthWorkspace() workspace: Workspace,
+  ): Promise<{
+    enabled: boolean;
+    dataDir: string;
+    pollIntervalMs: number;
+    debounceMs: number;
+    serviceUserConfigured: boolean;
+  }> {
+    this.assertAdmin(user, workspace);
+    return {
+      enabled: this.environmentService.isGitSyncEnabled(),
+      dataDir: this.environmentService.getGitSyncDataDir(),
+      pollIntervalMs: this.environmentService.getGitSyncPollIntervalMs(),
+      debounceMs: this.environmentService.getGitSyncDebounceMs(),
+      serviceUserConfigured: Boolean(
+        this.environmentService.getGitSyncServiceUserId(),
+      ),
+    };
+  }
+}

apps/server/src/integrations/git-sync/git-sync.loader.ts

@@ -0,0 +1,53 @@
+import { pathToFileURL } from 'node:url';
+import { esmImport } from '../../common/helpers/esm-import';
+import type {
+  VaultGit as VaultGitClass,
+  vaultGitEnv as vaultGitEnvFn,
+  runCycle as runCycleFn,
+  parseDocmostMarkdown as parseDocmostMarkdownFn,
+  markdownToProseMirror as markdownToProseMirrorFn,
+} from '@docmost/git-sync';
+
+/**
+ * Runtime value-export surface of the ESM-only `@docmost/git-sync` package that
+ * the server consumes. Types are imported with `import type` (erased at compile,
+ * no runtime require); only the VALUE exports below need the dynamic-load
+ * treatment so a CJS `require()` of the ESM package never happens.
+ */
+interface GitSyncModule {
+  VaultGit: typeof VaultGitClass;
+  vaultGitEnv: typeof vaultGitEnvFn;
+  runCycle: typeof runCycleFn;
+  parseDocmostMarkdown: typeof parseDocmostMarkdownFn;
+  markdownToProseMirror: typeof markdownToProseMirrorFn;
+}
+
+// The CJS->ESM dynamic-import bridge lives in one shared helper
+// (common/helpers/esm-import.ts); see it for why `import()` must be hidden from
+// the TS commonjs downleveler. The typed `loadGitSync()` wrapper stays here.
+
+// Memoize the in-flight/loaded module so the dynamic import runs at most once.
+let modulePromise: Promise<GitSyncModule> | null = null;
+
+/**
+ * Lazily load the ESM-only `@docmost/git-sync` package (cached). Resolves the
+ * package entry to an absolute path, then imports it as a `file://` URL so the
+ * package "exports" map is honoured without bare-specifier resolution-base
+ * fragility.
+ */
+export async function loadGitSync(): Promise<GitSyncModule> {
+  if (!modulePromise) {
+    modulePromise = (async () => {
+      const entry = require.resolve('@docmost/git-sync');
+      const mod = (await esmImport(
+        pathToFileURL(entry).href,
+      )) as GitSyncModule;
+      return mod;
+    })().catch((err) => {
+      // Do not cache a rejected import — allow the next call to retry.
+      modulePromise = null;
+      throw err;
+    });
+  }
+  return modulePromise;
+}

apps/server/src/integrations/git-sync/git-sync.module.ts

@@ -0,0 +1,62 @@
+import { Module } from '@nestjs/common';
+import { ScheduleModule } from '@nestjs/schedule';
+import { DatabaseModule } from '@docmost/db/database.module';
+import { EnvironmentModule } from '../environment/environment.module';
+import { CollaborationModule } from '../../collaboration/collaboration.module';
+import { PageModule } from '../../core/page/page.module';
+import { AuthModule } from '../../core/auth/auth.module';
+import { GitmostDataSourceService } from './services/gitmost-datasource.service';
+import { GitSyncOrchestrator } from './services/git-sync.orchestrator';
+import { SpaceLockService } from './services/space-lock.service';
+import { VaultRegistryService } from './services/vault-registry.service';
+import { PageChangeListener } from './listeners/page-change.listener';
+import { GitSyncController } from './git-sync.controller';
+import { GitHttpBackendService } from './http/git-http-backend.service';
+import { GitHttpService } from './http/git-http.service';
+
+/**
+ * The git-sync control plane. Wires the native datasource, the
+ * orchestrator (poll + leader-lock), the per-space vault registry, the
+ * event-driven listener, and the admin trigger controller.
+ *
+ * Imports:
+ *   - DatabaseModule (global) — PageRepo / SpaceRepo / KyselyDB for the
+ *     datasource + orchestrator queries;
+ *   - EnvironmentModule (global) — EnvironmentService config;
+ *   - CollaborationModule — exports CollaborationGateway for native body writes;
+ *   - PageModule — exports PageService for structural mutations;
+ *   - ScheduleModule (NOT forRoot) — so SchedulerRegistry is injectable (the
+ *     orchestrator registers a DYNAMIC poll interval in onModuleInit). forRoot()
+ *     is already registered globally by TelemetryModule; importing the plain
+ *     module here avoids a duplicate scheduler registration.
+ *
+ * RedisService is provided by the global RedisModule (app.module) and CASL's
+ * WorkspaceAbilityFactory by the global CaslModule — both resolve without an
+ * explicit import here.
+ */
+@Module({
+  imports: [
+    DatabaseModule,
+    EnvironmentModule,
+    CollaborationModule,
+    PageModule,
+    // AuthModule exports AuthService (verifyUserCredentials for /git HTTP Basic).
+    AuthModule,
+    ScheduleModule,
+  ],
+  controllers: [GitSyncController],
+  providers: [
+    GitmostDataSourceService,
+    GitSyncOrchestrator,
+    SpaceLockService,
+    VaultRegistryService,
+    PageChangeListener,
+    // /git smart-HTTP host (the raw Fastify route in main.ts resolves these).
+    GitHttpBackendService,
+    GitHttpService,
+  ],
+  // Exported so the raw Fastify route registered in main.ts can resolve the
+  // handler from the Nest container (app.get(GitHttpService)).
+  exports: [GitHttpService],
+})
+export class GitSyncModule {}

apps/server/src/integrations/git-sync/http/git-http-backend.service.spec.ts

@@ -0,0 +1,414 @@
+// Unit tests for the pure CGI-response helpers used by GitHttpBackendService.
+// The header/body split MUST treat the body as binary (Buffer) and never
+// stringify it; the Status: header sets the HTTP status (default 200).
+import { EventEmitter } from 'node:events';
+import { spawn } from 'node:child_process';
+
+// Mock the spawn boundary so run() never launches a real `git http-backend`; the
+// fake child lets us drive every stdout/stderr/error/close branch by hand.
+jest.mock('node:child_process', () => ({ spawn: jest.fn() }));
+// vaultGitEnv just builds the CGI env overlay; stub it to a passthrough so the
+// service runs without the real engine. The service loads it at runtime via the
+// `loadGitSync()` bridge (the ESM `@docmost/git-sync` package cannot be
+// `require()`d under jest), so we mock that loader rather than the package.
+jest.mock('../git-sync.loader', () => ({
+  loadGitSync: jest.fn(async () => ({
+    vaultGitEnv: (overlay: Record<string, string>) => overlay,
+  })),
+}));
+
+import {
+  parseCgiResponse,
+  splitCgiBuffer,
+  buildGitBackendCgiEnv,
+  GitHttpBackendService,
+} from './git-http-backend.service';
+import { Logger } from '@nestjs/common';
+import type { GitHttpBackendRequest } from './git-http-backend.service';
+
+const spawnMock = spawn as unknown as jest.Mock;
+
+/** A fake `git http-backend` child: EventEmitter + stdout/stderr/stdin streams. */
+function fakeChild() {
+  const child = new EventEmitter() as any;
+  child.stdout = new EventEmitter();
+  child.stderr = new EventEmitter();
+  // stdin is written/ended/piped to; capture the calls, swallow nothing.
+  child.stdin = Object.assign(new EventEmitter(), {
+    end: jest.fn(),
+    write: jest.fn(),
+  });
+  // The watchdog kills the child on timeout; capture the signal.
+  child.kill = jest.fn();
+  return child;
+}
+
+/** A fake raw Node ServerResponse capturing status/headers/body/end. */
+function fakeRes() {
+  const res: any = {
+    headersSent: false,
+    writableEnded: false,
+    statusCode: 200,
+    _headers: {} as Record<string, string>,
+    _written: [] as Buffer[],
+    setHeader: jest.fn((name: string, value: string) => {
+      res._headers[name] = value;
+    }),
+    write: jest.fn((chunk: Buffer) => {
+      res._written.push(chunk);
+      return true;
+    }),
+    end: jest.fn((chunk?: Buffer | string) => {
+      if (chunk !== undefined) res._written.push(chunk as Buffer);
+      res.writableEnded = true;
+    }),
+  };
+  return res;
+}
+
+/** A fake raw Node IncomingMessage (GET => no body piped). */
+function fakeReq() {
+  const req = new EventEmitter() as any;
+  req.pipe = jest.fn();
+  return req;
+}
+
+const baseRequest: GitHttpBackendRequest = {
+  spaceId: 'space-1',
+  subpath: 'info/refs',
+  method: 'GET',
+  queryString: 'service=git-upload-pack',
+  contentType: '',
+  remoteUser: 'alice@example.com',
+};
+
+function buildService(backendTimeoutMs = 120000) {
+  const env = {
+    getGitSyncDataDir: jest.fn(() => '/vaults'),
+    // The watchdog timeout for the spawned git http-backend. Tests inject a tiny
+    // value (or use fake timers) to drive the timeout branch.
+    getGitSyncBackendTimeoutMs: jest.fn(() => backendTimeoutMs),
+  };
+  return new GitHttpBackendService(env as any);
+}
+
+// `run()` now awaits the async `loadGitSync()` bridge before it spawns the
+// child, so the spawn (and its stream-handler wiring) happens one microtask
+// after `run()` is called. These tests drive the fake child synchronously, so
+// flush the microtask queue first to let `run()` reach the spawn.
+const flush = () => new Promise((resolve) => setImmediate(resolve));
+
+describe('GitHttpBackendService.run', () => {
+  beforeEach(() => {
+    spawnMock.mockReset();
+    jest.spyOn(Logger.prototype, 'warn').mockImplementation(() => undefined);
+    jest.spyOn(Logger.prototype, 'error').mockImplementation(() => undefined);
+  });
+  afterEach(() => jest.restoreAllMocks());
+
+  it('(a) responds 500 when the child errors before any headers were written', async () => {
+    const child = fakeChild();
+    spawnMock.mockReturnValue(child);
+    const service = buildService();
+    const res = fakeRes();
+
+    const p = service.run(baseRequest, fakeReq(), res);
+    await flush();
+    // Emit a child 'error' before any stdout -> 500, headers not already sent.
+    child.emit('error', new Error('ENOENT spawn git'));
+    await p;
+
+    expect(res.statusCode).toBe(500);
+    expect(res._headers['Content-Type']).toBe('text/plain');
+    expect(res.end).toHaveBeenCalledWith('Internal server error');
+  });
+
+  it('(a) responds 500 when the child closes before a complete CGI header block', async () => {
+    const child = fakeChild();
+    spawnMock.mockReturnValue(child);
+    const service = buildService();
+    const res = fakeRes();
+
+    const p = service.run(baseRequest, fakeReq(), res);
+    await flush();
+    // stderr diagnostics, then a close with no valid CGI output -> 500.
+    child.stderr.emit('data', Buffer.from('fatal: boom'));
+    child.emit('close', 128);
+    await p;
+
+    expect(res.statusCode).toBe(500);
+    expect(res.end).toHaveBeenCalledWith('Internal server error');
+  });
+
+  it('(b) parses the CGI header block, sets status/headers, writes the body', async () => {
+    const child = fakeChild();
+    spawnMock.mockReturnValue(child);
+    const service = buildService();
+    const res = fakeRes();
+
+    const p = service.run(baseRequest, fakeReq(), res);
+    await flush();
+    // A full CGI response: status line + header + blank line + body.
+    child.stdout.emit(
+      'data',
+      Buffer.from(
+        'Status: 200 OK\r\nContent-Type: application/x-git-upload-pack-advertisement\r\n\r\nPACKBODY',
+        'utf8',
+      ),
+    );
+    child.emit('close', 0);
+    await p;
+
+    expect(res.statusCode).toBe(200);
+    expect(res._headers['Content-Type']).toBe(
+      'application/x-git-upload-pack-advertisement',
+    );
+    expect(Buffer.concat(res._written.map((c) => Buffer.from(c))).toString()).toContain(
+      'PACKBODY',
+    );
+    expect(res.writableEnded).toBe(true);
+  });
+
+  it('(c) swallows a stdout stream error (EPIPE) without throwing or 500ing', async () => {
+    const child = fakeChild();
+    spawnMock.mockReturnValue(child);
+    const service = buildService();
+    const res = fakeRes();
+    const warnSpy = jest.spyOn(Logger.prototype, 'warn');
+
+    const p = service.run(baseRequest, fakeReq(), res);
+    await flush();
+    // The stdout 'error' handler must absorb this — no unhandled throw, no 500.
+    expect(() => child.stdout.emit('error', new Error('EPIPE'))).not.toThrow();
+    expect(() => child.stderr.emit('error', new Error('EPIPE'))).not.toThrow();
+    expect(warnSpy).toHaveBeenCalled();
+    expect(res.statusCode).not.toBe(500);
+
+    // Let run() settle so the promise does not dangle.
+    child.emit('close', 0);
+    await p;
+  });
+
+  it('(d) timeout: a child that never closes is killed and a 500 is sent', async () => {
+    // The child never emits stdout/close (a stalled git-receive-pack). With a
+    // tiny injected watchdog timeout the run() promise must still resolve: the
+    // child is killed and a clean 500 is sent (no headers were sent yet).
+    const child = fakeChild();
+    spawnMock.mockReturnValue(child);
+    const service = buildService(5); // 5ms watchdog
+    const res = fakeRes();
+    const warnSpy = jest.spyOn(Logger.prototype, 'warn');
+
+    // run() resolves only via the watchdog firing (no close/error emitted).
+    await service.run(baseRequest, fakeReq(), res);
+
+    expect(child.kill).toHaveBeenCalledWith('SIGTERM');
+    expect(warnSpy).toHaveBeenCalled();
+    expect(res.statusCode).toBe(500);
+    expect(res.end).toHaveBeenCalledWith('Internal server error');
+  });
+
+  it('(d) timeout watchdog is cleared on a normal close (no kill, no 500)', async () => {
+    // A normal request that completes well within the watchdog window must NOT be
+    // killed and must NOT trip the timeout 500 — the timer is cleared on close.
+    jest.useFakeTimers();
+    try {
+      const child = fakeChild();
+      spawnMock.mockReturnValue(child);
+      const service = buildService(120000);
+      const res = fakeRes();
+
+      const p = service.run(baseRequest, fakeReq(), res);
+      // loadGitSync resolves on a real microtask; advance it under fake timers.
+      await Promise.resolve();
+      await Promise.resolve();
+
+      child.stdout.emit(
+        'data',
+        Buffer.from('Status: 200 OK\r\nContent-Type: text/plain\r\n\r\nOK', 'utf8'),
+      );
+      child.emit('close', 0);
+      await p;
+
+      // The watchdog never fired even if we advance past its window.
+      jest.advanceTimersByTime(200000);
+      expect(child.kill).not.toHaveBeenCalled();
+      expect(res.statusCode).toBe(200);
+    } finally {
+      jest.useRealTimers();
+    }
+  });
+
+  it('spawn throwing synchronously -> 500 (spawn-failed)', async () => {
+    spawnMock.mockImplementation(() => {
+      throw new Error('spawn EACCES');
+    });
+    const service = buildService();
+    const res = fakeRes();
+
+    await service.run(baseRequest, fakeReq(), res);
+
+    expect(res.statusCode).toBe(500);
+    expect(res.end).toHaveBeenCalledWith('Internal server error');
+  });
+
+  it('(abort) an ALREADY-aborted signal -> no spawn, 500 lock-lost', async () => {
+    // The per-space lock was already lost before run() reached the spawn: we must
+    // NOT start writing the working tree after a possible lock takeover.
+    const child = fakeChild();
+    spawnMock.mockReturnValue(child);
+    const service = buildService();
+    const res = fakeRes();
+
+    const controller = new AbortController();
+    controller.abort();
+    await service.run(baseRequest, fakeReq(), res, controller.signal);
+
+    expect(spawnMock).not.toHaveBeenCalled();
+    expect(res.statusCode).toBe(500);
+    expect(res.end).toHaveBeenCalledWith('Internal server error');
+  });
+
+  it('(abort) a live signal aborted mid-request -> child SIGTERM + response closed', async () => {
+    // The lock lapses mid-push: the abort fires, the child is killed (SIGTERM,
+    // then SIGKILL on escalation), and the response is finished.
+    const child = fakeChild();
+    spawnMock.mockReturnValue(child);
+    const service = buildService();
+    const res = fakeRes();
+    const warnSpy = jest.spyOn(Logger.prototype, 'warn');
+
+    const controller = new AbortController();
+    const p = service.run(baseRequest, fakeReq(), res, controller.signal);
+    await flush(); // let run() reach the spawn + wire the abort listener
+    controller.abort();
+    await p;
+
+    expect(child.kill).toHaveBeenCalledWith('SIGTERM');
+    expect(warnSpy).toHaveBeenCalled();
+    // No headers were sent before the abort -> a clean 500 is sent and ended.
+    expect(res.statusCode).toBe(500);
+    expect(res.writableEnded).toBe(true);
+  });
+});
+
+describe('buildGitBackendCgiEnv', () => {
+  const base = {
+    spaceId: 'space-1',
+    subpath: 'info/refs',
+    method: 'GET',
+    queryString: 'service=git-upload-pack',
+    contentType: '',
+    remoteUser: 'alice@example.com',
+  };
+
+  it('points PATH_INFO at the NON-bare repo dir (no .git suffix)', () => {
+    // Regression guard: the vault lives at <root>/<spaceId> (a working repo), so
+    // PATH_INFO must be /<spaceId>/<subpath>. A `.git` suffix made git
+    // http-backend resolve <root>/<spaceId>.git and 404 every fetch/push.
+    const env = buildGitBackendCgiEnv(base, '/vaults');
+    expect(env.PATH_INFO).toBe('/space-1/info/refs');
+    expect(env.PATH_INFO).not.toContain('.git');
+    expect(env.GIT_PROJECT_ROOT).toBe('/vaults');
+  });
+
+  it('forwards method/query/content-type/remote-user and exports all repos', () => {
+    const env = buildGitBackendCgiEnv(
+      { ...base, method: 'POST', subpath: 'git-receive-pack', contentType: 'application/x-git-receive-pack-request', queryString: '' },
+      '/vaults',
+    );
+    expect(env.REQUEST_METHOD).toBe('POST');
+    expect(env.PATH_INFO).toBe('/space-1/git-receive-pack');
+    expect(env.CONTENT_TYPE).toBe('application/x-git-receive-pack-request');
+    expect(env.REMOTE_USER).toBe('alice@example.com');
+    expect(env.GIT_HTTP_EXPORT_ALL).toBe('1');
+  });
+
+  it('sets GIT_PROTOCOL only when the client sent the header', () => {
+    expect(buildGitBackendCgiEnv(base, '/vaults').GIT_PROTOCOL).toBeUndefined();
+    expect(
+      buildGitBackendCgiEnv({ ...base, gitProtocol: 'version=2' }, '/vaults')
+        .GIT_PROTOCOL,
+    ).toBe('version=2');
+  });
+});
+
+describe('parseCgiResponse', () => {
+  it('defaults to status 200 with no Status header', () => {
+    const r = parseCgiResponse('Content-Type: application/x-git-upload-pack-result');
+    expect(r.statusCode).toBe(200);
+    expect(r.headers).toEqual([
+      ['Content-Type', 'application/x-git-upload-pack-result'],
+    ]);
+  });
+
+  it('honors a Status header and does not forward it', () => {
+    const r = parseCgiResponse('Status: 404 Not Found\nContent-Type: text/plain');
+    expect(r.statusCode).toBe(404);
+    expect(r.headers).toEqual([['Content-Type', 'text/plain']]);
+  });
+
+  it('parses multiple headers and trims whitespace', () => {
+    const r = parseCgiResponse(
+      'Status: 403 Forbidden\r\nContent-Type:  text/plain \r\nX-Foo:  bar ',
+    );
+    expect(r.statusCode).toBe(403);
+    expect(r.headers).toEqual([
+      ['Content-Type', 'text/plain'],
+      ['X-Foo', 'bar'],
+    ]);
+  });
+
+  it('ignores malformed (colon-less) lines defensively', () => {
+    const r = parseCgiResponse('Content-Type: text/plain\ngarbage-line\nX-A: b');
+    expect(r.statusCode).toBe(200);
+    expect(r.headers).toEqual([
+      ['Content-Type', 'text/plain'],
+      ['X-A', 'b'],
+    ]);
+  });
+
+  it('ignores an out-of-range Status code and keeps the default', () => {
+    const r = parseCgiResponse('Status: not-a-number\nContent-Type: text/plain');
+    expect(r.statusCode).toBe(200);
+  });
+
+  it('treats the Status header case-insensitively', () => {
+    const r = parseCgiResponse('status: 500 Boom');
+    expect(r.statusCode).toBe(500);
+    expect(r.headers).toEqual([]);
+  });
+});
+
+describe('splitCgiBuffer', () => {
+  it('splits on a CRLF blank line and keeps the body as bytes', () => {
+    const buf = Buffer.concat([
+      Buffer.from('Status: 200 OK\r\nContent-Type: text/plain\r\n\r\n', 'utf8'),
+      Buffer.from([0x00, 0x01, 0x02, 0xff]),
+    ]);
+    const split = splitCgiBuffer(buf);
+    expect(split).not.toBeNull();
+    expect(split!.headerText).toBe('Status: 200 OK\r\nContent-Type: text/plain');
+    expect(Array.from(split!.body)).toEqual([0x00, 0x01, 0x02, 0xff]);
+  });
+
+  it('splits on a bare LF blank line', () => {
+    const buf = Buffer.from('Content-Type: text/plain\n\nhello', 'utf8');
+    const split = splitCgiBuffer(buf);
+    expect(split).not.toBeNull();
+    expect(split!.headerText).toBe('Content-Type: text/plain');
+    expect(split!.body.toString('utf8')).toBe('hello');
+  });
+
+  it('returns an empty body when nothing follows the separator', () => {
+    const buf = Buffer.from('Content-Type: text/plain\r\n\r\n', 'utf8');
+    const split = splitCgiBuffer(buf);
+    expect(split).not.toBeNull();
+    expect(split!.body.length).toBe(0);
+  });
+
+  it('returns null when there is no blank-line separator yet', () => {
+    const buf = Buffer.from('Content-Type: text/plain\r\nincomplete', 'utf8');
+    expect(splitCgiBuffer(buf)).toBeNull();
+  });
+});

apps/server/src/integrations/git-sync/http/git-http-backend.service.ts

@@ -0,0 +1,406 @@
+import { Injectable, Logger } from '@nestjs/common';
+import { spawn } from 'node:child_process';
+import type { IncomingMessage, ServerResponse } from 'node:http';
+import { loadGitSync } from '../git-sync.loader';
+import { EnvironmentService } from '../../environment/environment.service';
+
+/** The parsed first part of a CGI response: the HTTP status + header pairs. */
+export interface ParsedCgiResponse {
+  statusCode: number;
+  /** Lower-cased? No — keep header names verbatim as git http-backend emits. */
+  headers: Array<[string, string]>;
+}
+
+/**
+ * Parse the CGI header block emitted by `git http-backend` into an HTTP status
+ * and a list of header pairs. The input is ONLY the header text (everything up
+ * to, but not including, the blank-line separator) — the binary body is split
+ * off by the caller on the raw Buffer (never stringified).
+ *
+ * CGI semantics (RFC 3875 §6): a `Status: <code> <reason>` header sets the HTTP
+ * status (default 200 when absent). Every other header is forwarded verbatim.
+ * Header lines are `Name: value`; a line without a ':' is ignored defensively.
+ *
+ * Pure + framework-free so it is unit-testable in isolation.
+ */
+export function parseCgiResponse(headerBlock: string): ParsedCgiResponse {
+  let statusCode = 200;
+  const headers: Array<[string, string]> = [];
+
+  // Header lines may be separated by CRLF or LF; split on either.
+  const lines = headerBlock.split(/\r?\n/);
+  for (const line of lines) {
+    if (line.length === 0) continue;
+    const sep = line.indexOf(':');
+    if (sep === -1) continue; // not a header line — ignore defensively
+    const name = line.slice(0, sep).trim();
+    const value = line.slice(sep + 1).trim();
+    if (name.toLowerCase() === 'status') {
+      // `Status: 404 Not Found` — the leading integer is the HTTP status code.
+      const code = parseInt(value, 10);
+      if (Number.isFinite(code) && code >= 100 && code <= 599) {
+        statusCode = code;
+      }
+      continue; // never forward the CGI Status header itself
+    }
+    headers.push([name, value]);
+  }
+
+  return { statusCode, headers };
+}
+
+/**
+ * Split a raw CGI response buffer at the first blank-line boundary
+ * (`\r\n\r\n` or `\n\n`). Returns the header text and the remaining body bytes.
+ * Returns null when no blank-line separator is present (a malformed response).
+ *
+ * Pure (operates on Buffers, never stringifies the body) so it is testable.
+ */
+export function splitCgiBuffer(
+  buf: Buffer,
+): { headerText: string; body: Buffer } | null {
+  // Prefer the CRLF separator; fall back to bare LF.
+  let idx = buf.indexOf('\r\n\r\n');
+  let sepLen = 4;
+  if (idx === -1) {
+    idx = buf.indexOf('\n\n');
+    sepLen = 2;
+  }
+  if (idx === -1) return null;
+  const headerText = buf.subarray(0, idx).toString('utf8');
+  const body = buf.subarray(idx + sepLen);
+  return { headerText, body };
+}
+
+/** A parsed git smart-HTTP request, resolved by the controller/handler. */
+export interface GitHttpBackendRequest {
+  /** The space id (the on-disk vault dir name == GIT_PROJECT_ROOT child). */
+  spaceId: string;
+  /** The subpath after `<spaceId>.git/`, e.g. `info/refs` or `git-receive-pack`. */
+  subpath: string;
+  /** REQUEST_METHOD — `GET` or `POST`. */
+  method: string;
+  /** Raw query string WITHOUT the leading '?', e.g. `service=git-receive-pack`. */
+  queryString: string;
+  /** Content-Type header value (may be empty for GET). */
+  contentType: string;
+  /** The Git-Protocol request header value, or undefined when absent. */
+  gitProtocol?: string;
+  /** Authenticated user email — used as REMOTE_USER (reflog identity). */
+  remoteUser: string;
+}
+
+/**
+ * Bridges an HTTP git smart-protocol request to `git http-backend` (the CGI that
+ * implements the entire smart-HTTP protocol: info/refs, upload-pack,
+ * receive-pack, protocol v2, dumb fallback). We do NOT reimplement pkt-line.
+ *
+ * The Fastify reply is hijacked by the caller; this service streams the request
+ * body to the child's stdin and writes the child's CGI response (status +
+ * headers parsed from the leading header block, then the raw binary body) to the
+ * Node response. Errors before any output produce a 500. Credentials are never
+ * logged.
+ */
+/**
+ * Build the `git http-backend` CGI environment overlay for one request (the
+ * variables layered on top of `vaultGitEnv`'s cwd-isolated base). Pure so the
+ * PATH_INFO / REMOTE_USER / conditional GIT_PROTOCOL wiring is unit-testable
+ * without spawning git.
+ *
+ * PATH_INFO is the repo-relative CGI path. The vault is a NON-BARE working repo
+ * on disk at `<dataDir>/<spaceId>` (the engine needs a working tree), so the
+ * repo directory git http-backend must resolve is `<spaceId>` — NOT
+ * `<spaceId>.git`. The URL carries the conventional `.git` suffix (stripped by
+ * parseGitPath into `spaceId`); re-appending it here pointed the CGI at a
+ * non-existent `<dataDir>/<spaceId>.git` and every fetch/push 404'd.
+ */
+export function buildGitBackendCgiEnv(
+  parsed: GitHttpBackendRequest,
+  projectRoot: string,
+): Record<string, string> {
+  const cgiEnv: Record<string, string> = {
+    GIT_PROJECT_ROOT: projectRoot,
+    GIT_HTTP_EXPORT_ALL: '1', // authz is done by us; no git-daemon-export-ok file
+    PATH_INFO: `/${parsed.spaceId}/${parsed.subpath}`,
+    REQUEST_METHOD: parsed.method,
+    QUERY_STRING: parsed.queryString,
+    CONTENT_TYPE: parsed.contentType,
+    REMOTE_USER: parsed.remoteUser,
+  };
+  // GIT_PROTOCOL is only set when the client sent the Git-Protocol header.
+  if (parsed.gitProtocol) {
+    cgiEnv.GIT_PROTOCOL = parsed.gitProtocol;
+  }
+  return cgiEnv;
+}
+
+@Injectable()
+export class GitHttpBackendService {
+  private readonly logger = new Logger(GitHttpBackendService.name);
+
+  constructor(private readonly environmentService: EnvironmentService) {}
+
+  /**
+   * Spawn `git http-backend` for one request and bridge it to the raw Node
+   * request/response. Resolves when the response has been fully written (the
+   * child exited and its output was flushed), or after a 500 was sent on an
+   * early failure. Never rejects — push ingestion relies on this resolving so
+   * the lock-held cycle body can run afterwards.
+   *
+   * `signal` (optional) is the git-sync per-space lock's lost-lock abort signal.
+   * A receive-pack writes `main`'s working tree, so if the lock lapses mid-push
+   * (heartbeat CAS miss / Redis outage) the signal fires and we kill the child —
+   * preventing it from continuing to write the working tree while another replica
+   * may have taken over the lock and started a cycle (warning #3).
+   */
+  async run(
+    parsed: GitHttpBackendRequest,
+    rawReq: IncomingMessage,
+    rawRes: ServerResponse,
+    signal?: AbortSignal,
+  ): Promise<void> {
+    const { vaultGitEnv } = await loadGitSync();
+    const projectRoot = this.environmentService.getGitSyncDataDir();
+    // Build the CGI env from the engine's cwd-isolated base (strips GIT_DIR /
+    // GIT_WORK_TREE), then layer the http-backend CGI variables. PATH is
+    // preserved (vaultGitEnv already copies process.env, so PATH carries
+    // through).
+    const env = vaultGitEnv(buildGitBackendCgiEnv(parsed, projectRoot));
+
+    return new Promise<void>((resolve) => {
+      let settled = false;
+      // Set once the child exists so the abort handler can target it.
+      let onAbort: (() => void) | null = null;
+      // The watchdog timer; cleared centrally in done() so EVERY settle path
+      // (close, error, timeout, abort) tears it down exactly once.
+      let watchdogTimer: ReturnType<typeof setTimeout> | undefined;
+      const done = () => {
+        if (settled) return;
+        settled = true;
+        if (watchdogTimer) clearTimeout(watchdogTimer);
+        // Detach the abort listener so a later lock loss does not fire into a
+        // request that already finished.
+        if (onAbort) {
+          signal?.removeEventListener('abort', onAbort);
+          onAbort = null;
+        }
+        resolve();
+      };
+
+      // Reject early if the lock was already lost before we even spawned: do not
+      // start writing the working tree after a possible lock takeover.
+      if (signal?.aborted) {
+        if (!rawRes.headersSent) this.send500(rawRes, 'lock-lost');
+        else
+          try {
+            rawRes.end();
+          } catch {
+            /* ignore */
+          }
+        return done();
+      }
+
+      let child: ReturnType<typeof spawn>;
+      try {
+        child = spawn('git', ['http-backend'], { env });
+      } catch (err) {
+        this.send500(rawRes, 'spawn-failed', err);
+        return done();
+      }
+
+      // Lost-lock abort: the per-space lock lapsed mid-request. Kill the child so
+      // a receive-pack stops writing `main`'s working tree before another replica
+      // (which may now hold the lock) starts a cycle. Same kill+finish path the
+      // watchdog uses (extracted into terminateChild).
+      onAbort = () => {
+        this.terminateChild(
+          child,
+          rawRes,
+          headerParsed,
+          'lock-lost',
+          'git http-backend aborted (git-sync lock lost mid-request); killing child',
+          done,
+        );
+      };
+      signal?.addEventListener('abort', onAbort);
+
+      // Watchdog: a client that opens git-receive-pack and stalls keeps the
+      // child alive forever, so run() never resolves and (because this runs
+      // inside withSpaceLock) the per-space lock is held + heartbeat-refreshed
+      // indefinitely. Bound the request: on expiry kill the child, send a clean
+      // 500 if nothing was sent yet, and settle the promise. `.unref()` so the
+      // timer never keeps the event loop alive; ALWAYS cleared in done().
+      watchdogTimer = setTimeout(() => {
+        this.terminateChild(
+          child,
+          rawRes,
+          headerParsed,
+          'timeout',
+          `git http-backend timed out after ` +
+            `${this.environmentService.getGitSyncBackendTimeoutMs()}ms; killing child`,
+          done,
+        );
+      }, this.environmentService.getGitSyncBackendTimeoutMs());
+      watchdogTimer.unref?.();
+
+      // Accumulate stdout until we have the full CGI header block, then write the
+      // parsed status/headers and start streaming the remaining body bytes.
+      let headerParsed = false;
+      let pending: Buffer = Buffer.alloc(0);
+
+      const flushHeadersAndBody = (chunk: Buffer): void => {
+        pending = Buffer.concat([pending, chunk]);
+        const split = splitCgiBuffer(pending);
+        if (!split) return; // header block not complete yet
+        headerParsed = true;
+        const { statusCode, headers } = parseCgiResponse(split.headerText);
+        rawRes.statusCode = statusCode;
+        for (const [name, value] of headers) {
+          rawRes.setHeader(name, value);
+        }
+        if (split.body.length > 0) rawRes.write(split.body);
+        pending = Buffer.alloc(0);
+      };
+
+      child.stdout?.on('data', (chunk: Buffer) => {
+        if (headerParsed) {
+          rawRes.write(chunk);
+        } else {
+          flushHeadersAndBody(chunk);
+        }
+      });
+      // A stream 'error' (e.g. EPIPE when the client aborts mid-response) is an
+      // EventEmitter 'error' with no listener -> Node rethrows it as an uncaught
+      // exception and crashes the process. Swallow + log it (never echo to the
+      // client); child.on('close')/'error' below drives the actual cleanup.
+      child.stdout?.on('error', (err) => {
+        this.logger.warn(`git http-backend stdout stream error: ${err.message}`);
+      });
+
+      let stderr = '';
+      child.stderr?.on('data', (chunk: Buffer) => {
+        // Capture for diagnostics; never echo to the client. http-backend writes
+        // CGI errors here. We do NOT log the request body or any credentials.
+        if (stderr.length < 8192) stderr += chunk.toString('utf8');
+      });
+      child.stderr?.on('error', (err) => {
+        this.logger.warn(`git http-backend stderr stream error: ${err.message}`);
+      });
+
+      child.on('error', (err) => {
+        // The watchdog timer is cleared centrally in done().
+        if (!headerParsed && !rawRes.headersSent) {
+          this.send500(rawRes, 'child-error', err);
+        } else {
+          // Output already started — we can only terminate the stream.
+          try {
+            rawRes.end();
+          } catch {
+            /* ignore */
+          }
+        }
+        done();
+      });
+
+      child.on('close', (code) => {
+        // The watchdog timer is cleared centrally in done().
+        if (!headerParsed && !rawRes.headersSent) {
+          // The child exited before emitting a complete CGI header block.
+          this.logger.error(
+            `git http-backend produced no valid response (exit ${code}) for ` +
+              `space; stderr: ${stderr.trim().slice(0, 500)}`,
+          );
+          this.send500(rawRes, 'no-output');
+        } else {
+          try {
+            rawRes.end();
+          } catch {
+            /* ignore */
+          }
+        }
+        done();
+      });
+
+      // Pipe the request body to the child's stdin. For GET there is no body, so
+      // end stdin immediately. We pipe `rawReq` (the raw Node stream) directly so
+      // large pushes are streamed, not buffered.
+      if (parsed.method === 'POST') {
+        rawReq.pipe(child.stdin!);
+        rawReq.on('error', () => {
+          try {
+            child.stdin?.end();
+          } catch {
+            /* ignore */
+          }
+        });
+      } else {
+        child.stdin?.end();
+      }
+      // Swallow EPIPE etc. on the child's stdin so a client disconnect does not
+      // crash the process.
+      child.stdin?.on('error', () => {
+        /* ignore broken-pipe on stdin */
+      });
+    });
+  }
+
+  /**
+   * Kill the child (SIGTERM, then SIGKILL after a grace period if it ignores the
+   * term) and finish the HTTP response cleanly, then settle. Shared by the two
+   * forced-termination paths — the watchdog timeout and the lost-lock abort —
+   * which differ ONLY by the log line and the send500 `reason`. If no response
+   * has started a clean 500 is sent; otherwise the in-flight stream is just
+   * ended. Never throws (a thrown kill/end would crash the request).
+   */
+  private terminateChild(
+    child: ReturnType<typeof spawn>,
+    rawRes: ServerResponse,
+    responseStarted: boolean,
+    send500Reason: string,
+    logMessage: string,
+    done: () => void,
+  ): void {
+    this.logger.warn(logMessage);
+    try {
+      child.kill('SIGTERM');
+      // Escalate to SIGKILL shortly after in case SIGTERM is ignored.
+      const sigkill = setTimeout(() => {
+        try {
+          child.kill('SIGKILL');
+        } catch {
+          /* ignore */
+        }
+      }, 2000);
+      sigkill.unref?.();
+    } catch {
+      /* ignore */
+    }
+    if (!responseStarted && !rawRes.headersSent) {
+      this.send500(rawRes, send500Reason);
+    } else {
+      try {
+        rawRes.end();
+      } catch {
+        /* ignore */
+      }
+    }
+    done();
+  }
+
+  /** Send a clean 500 without leaking credentials or the request body. */
+  private send500(rawRes: ServerResponse, reason: string, err?: unknown): void {
+    const message = err instanceof Error ? err.message : undefined;
+    this.logger.error(
+      `git http-backend failed (${reason})${message ? `: ${message}` : ''}`,
+    );
+    try {
+      if (!rawRes.headersSent) {
+        rawRes.statusCode = 500;
+        rawRes.setHeader('Content-Type', 'text/plain');
+      }
+      rawRes.end('Internal server error');
+    } catch {
+      /* ignore */
+    }
+  }
+}

apps/server/src/integrations/git-sync/http/git-http.helpers.spec.ts

@@ -0,0 +1,211 @@
+// Unit tests for the pure /git smart-HTTP helpers: URL parsing, service->kind
+// mapping (read vs write), and the gating/auth decision precedence.
+import {
+  decideGitHttpGate,
+  parseGitPath,
+  resolveServiceKind,
+} from './git-http.helpers';
+
+describe('parseGitPath', () => {
+  it('parses spaceId + subpath, stripping the trailing .git', () => {
+    expect(parseGitPath('abc123.git/info/refs')).toEqual({
+      spaceId: 'abc123',
+      subpath: 'info/refs',
+    });
+  });
+
+  it('tolerates a leading slash', () => {
+    expect(parseGitPath('/abc.git/git-receive-pack')).toEqual({
+      spaceId: 'abc',
+      subpath: 'git-receive-pack',
+    });
+  });
+
+  it('returns an empty subpath for the bare repo root', () => {
+    expect(parseGitPath('abc.git')).toEqual({ spaceId: 'abc', subpath: '' });
+  });
+
+  it('returns null when the first segment lacks .git', () => {
+    expect(parseGitPath('abc/info/refs')).toBeNull();
+  });
+
+  it('returns null on an empty space id', () => {
+    expect(parseGitPath('.git/info/refs')).toBeNull();
+  });
+
+  it('rejects path traversal', () => {
+    expect(parseGitPath('abc.git/../../etc/passwd')).toBeNull();
+    expect(parseGitPath('..git/x')).toBeNull();
+  });
+
+  it('rejects percent-encoded dot/slash traversal in the subpath (case-insensitive)', () => {
+    expect(parseGitPath('abc.git/%2e%2e%2fetc/passwd')).toBeNull();
+    expect(parseGitPath('abc.git/%2E%2E/secret')).toBeNull();
+    expect(parseGitPath('abc.git/objects/%2fabsolute')).toBeNull();
+  });
+});
+
+describe('resolveServiceKind', () => {
+  it('GET info/refs?service=git-upload-pack -> read', () => {
+    expect(
+      resolveServiceKind({
+        method: 'GET',
+        subpath: 'info/refs',
+        service: 'git-upload-pack',
+      }),
+    ).toBe('read');
+  });
+
+  it('GET info/refs?service=git-receive-pack -> write', () => {
+    expect(
+      resolveServiceKind({
+        method: 'GET',
+        subpath: 'info/refs',
+        service: 'git-receive-pack',
+      }),
+    ).toBe('write');
+  });
+
+  it('POST git-upload-pack -> read', () => {
+    expect(
+      resolveServiceKind({ method: 'POST', subpath: 'git-upload-pack' }),
+    ).toBe('read');
+  });
+
+  it('POST git-receive-pack -> write', () => {
+    expect(
+      resolveServiceKind({ method: 'POST', subpath: 'git-receive-pack' }),
+    ).toBe('write');
+  });
+
+  it('a dumb-protocol GET (HEAD / objects) -> read', () => {
+    expect(resolveServiceKind({ method: 'GET', subpath: 'HEAD' })).toBe('read');
+    expect(
+      resolveServiceKind({ method: 'GET', subpath: 'objects/12/abcdef' }),
+    ).toBe('read');
+  });
+
+  it('info/refs with no/unknown service -> read (dumb discovery)', () => {
+    expect(resolveServiceKind({ method: 'GET', subpath: 'info/refs' })).toBe(
+      'read',
+    );
+  });
+
+  it('an unknown POST endpoint -> null', () => {
+    expect(resolveServiceKind({ method: 'POST', subpath: 'whatever' })).toBeNull();
+  });
+
+  it('an unsupported method -> null', () => {
+    expect(
+      resolveServiceKind({ method: 'DELETE', subpath: 'git-receive-pack' }),
+    ).toBeNull();
+  });
+});
+
+describe('decideGitHttpGate', () => {
+  const base = {
+    hasCredentials: true,
+    credentialsValid: true,
+    serviceKind: 'read' as const,
+    gitSyncEnabled: true,
+    gitHttpEnabled: true,
+    spaceExists: true,
+    spaceGitSyncEnabled: true,
+    userIsSpaceMember: true,
+    permissionGranted: true,
+  };
+
+  it('proceeds on the happy path', () => {
+    expect(decideGitHttpGate(base)).toEqual({ kind: 'proceed' });
+  });
+
+  it('401 when credentials are missing (even for a valid space)', () => {
+    expect(
+      decideGitHttpGate({ ...base, hasCredentials: false }),
+    ).toEqual({ kind: 'unauthorized' });
+  });
+
+  it('401 when credentials are present but invalid', () => {
+    expect(
+      decideGitHttpGate({ ...base, credentialsValid: false }),
+    ).toEqual({ kind: 'unauthorized' });
+  });
+
+  it('400 on an unparseable service kind', () => {
+    expect(decideGitHttpGate({ ...base, serviceKind: null })).toEqual({
+      kind: 'bad-request',
+    });
+  });
+
+  it('404 when the space is not git-sync-enabled (never reveals existence)', () => {
+    expect(
+      decideGitHttpGate({ ...base, spaceGitSyncEnabled: false }),
+    ).toEqual({ kind: 'not-found' });
+  });
+
+  it('404 when the space does not exist', () => {
+    expect(decideGitHttpGate({ ...base, spaceExists: false })).toEqual({
+      kind: 'not-found',
+    });
+  });
+
+  it('404 when git-sync is globally disabled', () => {
+    expect(decideGitHttpGate({ ...base, gitSyncEnabled: false })).toEqual({
+      kind: 'not-found',
+    });
+  });
+
+  it('404 when the git-http host is disabled', () => {
+    expect(decideGitHttpGate({ ...base, gitHttpEnabled: false })).toEqual({
+      kind: 'not-found',
+    });
+  });
+
+  it('403 when a MEMBER lacks the required permission (reader on write)', () => {
+    // A member of the space (existence already known to them) who lacks the role:
+    // 403 leaks nothing new.
+    expect(
+      decideGitHttpGate({
+        ...base,
+        serviceKind: 'write',
+        userIsSpaceMember: true,
+        permissionGranted: false,
+      }),
+    ).toEqual({ kind: 'forbidden' });
+  });
+
+  it('404 (NOT 403) when an authenticated NON-member hits a git-sync space', () => {
+    // SECURITY: a non-member must be indistinguishable from a missing/disabled
+    // space. If this returned 403, the 403↔404 difference would let any
+    // authenticated workspace user brute-force slugs to discover which spaces
+    // exist and which have git-sync enabled.
+    expect(
+      decideGitHttpGate({
+        ...base,
+        serviceKind: 'write',
+        userIsSpaceMember: false,
+        permissionGranted: false,
+      }),
+    ).toEqual({ kind: 'not-found' });
+    // Same for a read by a non-member.
+    expect(
+      decideGitHttpGate({
+        ...base,
+        serviceKind: 'read',
+        userIsSpaceMember: false,
+        permissionGranted: false,
+      }),
+    ).toEqual({ kind: 'not-found' });
+  });
+
+  it('still 401 (not 404) for missing creds against a disabled space', () => {
+    // Anonymous probe must always get 401 first, regardless of space state.
+    expect(
+      decideGitHttpGate({
+        ...base,
+        hasCredentials: false,
+        spaceGitSyncEnabled: false,
+      }),
+    ).toEqual({ kind: 'unauthorized' });
+  });
+});

apps/server/src/integrations/git-sync/http/git-http.helpers.ts

@@ -0,0 +1,164 @@
+// Pure, framework-free helpers for the /git smart-HTTP host. They carry no Nest
+// / DI / concrete-service imports so the request parsing and the auth/authz
+// gating DECISION can be unit-tested in isolation, and nothing here ever logs a
+// password or the Authorization header.
+
+/** The git operation a request maps to: a read (fetch/clone) or a write (push). */
+export type GitHttpServiceKind = 'read' | 'write';
+
+/** A parsed `/git/<spaceId>.git/<subpath>` URL. */
+export interface ParsedGitPath {
+  spaceId: string;
+  /** The subpath after `<spaceId>.git/` (no leading slash), e.g. `info/refs`. */
+  subpath: string;
+}
+
+/**
+ * Parse the `<rest>` of a `/git/<rest>` URL path (no query string) into the
+ * space id and the repo-relative subpath. The space id is the first path
+ * segment with its trailing `.git` stripped. Returns null when the shape does
+ * not match (missing `.git`, empty space id, traversal attempt).
+ *
+ * `rest` MUST already be URL-path-decoded of its query string by the caller
+ * (pass the pathname only). We reject `..` segments defensively even though
+ * http-backend resolves PATH_INFO against GIT_PROJECT_ROOT.
+ */
+export function parseGitPath(rest: string): ParsedGitPath | null {
+  // Strip a leading slash, then take the first segment as `<spaceId>.git`.
+  const clean = rest.replace(/^\/+/, '');
+  const slash = clean.indexOf('/');
+  const first = slash === -1 ? clean : clean.slice(0, slash);
+  const subpath = slash === -1 ? '' : clean.slice(slash + 1);
+
+  if (!first.endsWith('.git')) return null;
+  const spaceId = first.slice(0, -'.git'.length);
+  if (!spaceId) return null;
+
+  // Reject path traversal / degenerate ids in either component.
+  if (
+    spaceId === '.' ||
+    spaceId.includes('..') ||
+    spaceId.includes('/') ||
+    subpath.split('/').some((seg) => seg === '..')
+  ) {
+    return null;
+  }
+
+  // Defense-in-depth: reject percent-encoded dot/slash traversal (`%2e`, `%2f`,
+  // case-insensitive) in the subpath BEFORE it is used to build PATH_INFO — a
+  // decoder downstream could otherwise turn `%2e%2e%2f` back into `../`.
+  if (/%2e|%2f/i.test(subpath)) {
+    return null;
+  }
+
+  return { spaceId, subpath };
+}
+
+/**
+ * Map a parsed git request (method + subpath + query) to the required operation
+ * kind. The smart-HTTP shapes:
+ *   - GET  info/refs?service=git-upload-pack   -> read (fetch)
+ *   - GET  info/refs?service=git-receive-pack  -> write (push)
+ *   - POST git-upload-pack                      -> read (fetch)
+ *   - POST git-receive-pack                     -> write (push)
+ *   - any other dumb-protocol GET (HEAD, objects/…) -> read
+ * Returns null for an unsupported shape (e.g. a POST that is neither pack
+ * endpoint) so the caller can 403/404 rather than guess.
+ */
+export function resolveServiceKind(input: {
+  method: string;
+  subpath: string;
+  service?: string;
+}): GitHttpServiceKind | null {
+  const method = input.method.toUpperCase();
+  const subpath = input.subpath;
+
+  if (method === 'GET') {
+    if (subpath === 'info/refs') {
+      if (input.service === 'git-receive-pack') return 'write';
+      if (input.service === 'git-upload-pack') return 'read';
+      // info/refs without a known service: dumb-protocol discovery — read.
+      return 'read';
+    }
+    // Dumb-protocol object/ref fetches (HEAD, objects/…) are reads.
+    return 'read';
+  }
+
+  if (method === 'POST') {
+    if (subpath === 'git-receive-pack') return 'write';
+    if (subpath === 'git-upload-pack') return 'read';
+    return null; // unknown POST endpoint
+  }
+
+  return null; // unsupported method
+}
+
+/** The outcome of the gating/auth decision the request handler must enforce. */
+export type GitHttpGateDecision =
+  | { kind: 'unauthorized' } // 401 + WWW-Authenticate (missing/invalid creds)
+  | { kind: 'not-found' } // 404 (space hidden / sync or http disabled)
+  | { kind: 'forbidden' } // 403 (authenticated but lacks the permission)
+  | { kind: 'bad-request' } // 400 (unparseable git request shape)
+  | { kind: 'proceed' }; // run http-backend
+
+/**
+ * Pure gating decision, mirroring the handler precedence so it can be unit
+ * tested without the DB / CASL graph. Inputs are the already-resolved booleans
+ * the handler computes from EnvironmentService / SpaceRepo / SpaceAbilityFactory.
+ *
+ * Precedence (matches the spec):
+ *   1. no/invalid Basic credentials               -> 401 (regardless of space).
+ *   2. credentials present but invalid             -> 401.
+ *   3. unparseable git request shape               -> 400.
+ *   4. git-sync globally disabled, or git-http disabled, or the space is missing
+ *      / not git-sync-enabled, OR the authenticated user is NOT a member of the
+ *      space (has no role at all)                   -> 404 (never reveal existence).
+ *   5. a MEMBER of the space who lacks the required perm (e.g. a reader trying to
+ *      push)                                        -> 403.
+ *   6. otherwise                                    -> proceed.
+ *
+ * Note (4) is checked AFTER (1)/(2): an anonymous probe always gets 401 first;
+ * an authenticated user hitting a hidden/disabled space — OR a space they are not
+ * a member of — gets 404 (not 403). Folding non-membership into the 404 branch is
+ * a SECURITY requirement: if a non-member got 403 here (as a "permission denied")
+ * while a non-existent / sync-disabled space got 404, the 403↔404 difference would
+ * let any authenticated workspace user brute-force slugs to discover which spaces
+ * exist and which have git-sync enabled — including spaces they cannot see. 403 is
+ * therefore reserved for the one case where existence is ALREADY known to the
+ * caller because they ARE a member (so it leaks nothing new): a member without the
+ * required role. `userIsSpaceMember` is the resolved "the user has SOME role in
+ * this space" boolean (false when SpaceAbilityFactory.createForUser throws
+ * NotFound / the user has no role).
+ */
+export function decideGitHttpGate(input: {
+  hasCredentials: boolean;
+  credentialsValid: boolean;
+  serviceKind: GitHttpServiceKind | null;
+  gitSyncEnabled: boolean;
+  gitHttpEnabled: boolean;
+  spaceExists: boolean;
+  spaceGitSyncEnabled: boolean;
+  /** The user has SOME role in the space (false = non-member -> 404, not 403). */
+  userIsSpaceMember: boolean;
+  permissionGranted: boolean;
+}): GitHttpGateDecision {
+  if (!input.hasCredentials) return { kind: 'unauthorized' };
+  if (!input.credentialsValid) return { kind: 'unauthorized' };
+  if (input.serviceKind === null) return { kind: 'bad-request' };
+
+  if (
+    !input.gitSyncEnabled ||
+    !input.gitHttpEnabled ||
+    !input.spaceExists ||
+    !input.spaceGitSyncEnabled ||
+    // A non-member must be indistinguishable from a missing/disabled space: 404,
+    // never 403 (otherwise the 403↔404 split leaks space existence — see above).
+    !input.userIsSpaceMember
+  ) {
+    return { kind: 'not-found' };
+  }
+
+  if (!input.permissionGranted) return { kind: 'forbidden' };
+
+  return { kind: 'proceed' };
+}

apps/server/src/integrations/git-sync/http/git-http.service.spec.ts

@@ -0,0 +1,643 @@
+// Unit tests for GitHttpService — the /git smart-HTTP handler. Everything it
+// depends on (backend, auth, repos, ability factory, env, orchestrator) is
+// mocked so we exercise ONLY the handler wiring: workspace resolution (which is
+// done HERE, not by DomainMiddleware — see FIX 1), the auth/gating precedence,
+// the read-vs-write dispatch, and that a fetch does NOT take the lock.
+//
+// These tests deliberately NEVER set `req.raw.workspaceId`: the workspace must
+// come from WorkspaceRepo. If the handler regressed to reading
+// `req.raw.workspaceId`, the happy-path fetch test below would fail (the repo
+// would not be consulted and the request would 401).
+import {
+  Logger,
+  NotFoundException,
+  UnauthorizedException,
+} from '@nestjs/common';
+import { CREDENTIALS_MISMATCH_MESSAGE } from '../../../core/auth/auth.constants';
+import {
+  SpaceCaslAction,
+  SpaceCaslSubject,
+} from '../../../core/casl/interfaces/space-ability.type';
+import { GitHttpService } from './git-http.service';
+import { GitSyncLockHeldError } from '../services/git-sync.orchestrator';
+
+type AnyMock = jest.Mock;
+
+interface BuildOptions {
+  selfHosted?: boolean;
+  gitSyncEnabled?: boolean;
+  gitHttpEnabled?: boolean;
+  /** What workspaceRepo.findFirst() returns (self-hosted resolution). */
+  workspace?: { id: string } | null;
+  /** What spaceRepo.findById() returns. */
+  space?: { id: string; settings?: unknown } | null;
+  /** Result of authService.verifyUserCredentials: a user, or throw 401. */
+  user?: { id: string; email: string } | null;
+  /** Whether the created ability grants the requested action. */
+  abilityCan?: boolean;
+}
+
+interface Built {
+  service: GitHttpService;
+  env: Record<string, AnyMock>;
+  authService: { verifyUserCredentials: AnyMock };
+  spaceRepo: { findById: AnyMock };
+  workspaceRepo: { findFirst: AnyMock; findByHostname: AnyMock };
+  abilityFactory: { createForUser: AnyMock };
+  abilityCan: AnyMock;
+  vaultRegistry: { ensureServable: AnyMock };
+  orchestrator: {
+    ingestExternalPush: AnyMock;
+    serveReadAdvertisement: AnyMock;
+  };
+  backend: { run: AnyMock };
+}
+
+function build(opts: BuildOptions = {}): Built {
+  const {
+    selfHosted = true,
+    gitSyncEnabled = true,
+    gitHttpEnabled = true,
+    workspace = { id: 'ws-1' },
+    space = { id: 'space-1', settings: { gitSync: { enabled: true } } },
+    user = { id: 'user-1', email: 'dev@example.com' },
+    abilityCan = true,
+  } = opts;
+
+  const env: Record<string, AnyMock> = {
+    isSelfHosted: jest.fn(() => selfHosted),
+    isCloud: jest.fn(() => !selfHosted),
+    isGitSyncEnabled: jest.fn(() => gitSyncEnabled),
+    isGitSyncHttpEnabled: jest.fn(() => gitHttpEnabled),
+  };
+
+  const authService = {
+    verifyUserCredentials: jest.fn(async () => {
+      if (!user) throw new UnauthorizedException();
+      return user;
+    }),
+  };
+
+  const spaceRepo = { findById: jest.fn(async () => space) };
+
+  const workspaceRepo = {
+    findFirst: jest.fn(async () => workspace),
+    findByHostname: jest.fn(async () => workspace),
+  };
+
+  const abilityCanMock = jest.fn(() => abilityCan);
+  const abilityFactory = {
+    createForUser: jest.fn(async () => ({ can: abilityCanMock })),
+  };
+
+  const vaultRegistry = { ensureServable: jest.fn(async () => undefined) };
+  const orchestrator = {
+    ingestExternalPush: jest.fn(async () => undefined),
+    // The read-advertisement wrapper pins HEAD under the lock then serves; the
+    // mock just runs the serve callback so the read path still hits backend.run.
+    serveReadAdvertisement: jest.fn(
+      async (_spaceId: string, serve: () => Promise<void>) => serve(),
+    ),
+  };
+  const backend = { run: jest.fn(async () => undefined) };
+
+  const service = new GitHttpService(
+    env as any,
+    authService as any,
+    spaceRepo as any,
+    workspaceRepo as any,
+    abilityFactory as any,
+    vaultRegistry as any,
+    orchestrator as any,
+    backend as any,
+  );
+
+  return {
+    service,
+    env,
+    authService,
+    spaceRepo,
+    workspaceRepo,
+    abilityFactory,
+    abilityCan: abilityCanMock,
+    vaultRegistry,
+    orchestrator,
+    backend,
+  };
+}
+
+/** A fake Fastify reply capturing the terminal status/headers/body. */
+function fakeReply() {
+  const state: {
+    statusCode?: number;
+    headers: Record<string, string>;
+    body?: unknown;
+    hijacked: boolean;
+    sent: boolean;
+  } = { headers: {}, hijacked: false, sent: false };
+
+  const reply: any = {
+    header(name: string, value: string) {
+      state.headers[name] = value;
+      return reply;
+    },
+    status(code: number) {
+      state.statusCode = code;
+      return reply;
+    },
+    send(body: unknown) {
+      state.body = body;
+      state.sent = true;
+      return reply;
+    },
+    hijack() {
+      state.hijacked = true;
+    },
+    get sent() {
+      return state.sent;
+    },
+    // The raw Node response — only touched on the streaming/error paths.
+    raw: {
+      headersSent: false,
+      writableEnded: false,
+      statusCode: 200,
+      setHeader: jest.fn(),
+      end: jest.fn(),
+    },
+  };
+  return { reply, state };
+}
+
+/** A fake Fastify request for a /git smart-HTTP call. */
+function fakeRequest(opts: {
+  url: string;
+  method?: string;
+  authorization?: string;
+  host?: string;
+}) {
+  const { url, method = 'GET', authorization, host = 'docs.example.com' } = opts;
+  const headers: Record<string, string> = { host };
+  if (authorization) headers['authorization'] = authorization;
+  // query is parsed by Fastify; mirror the `service` param when present.
+  const qIdx = url.indexOf('?');
+  const query: Record<string, string> = {};
+  if (qIdx !== -1) {
+    for (const pair of url.slice(qIdx + 1).split('&')) {
+      const [k, v] = pair.split('=');
+      if (k) query[k] = v ?? '';
+    }
+  }
+  return {
+    url,
+    method,
+    headers,
+    query,
+    // raw is intentionally WITHOUT workspaceId — the handler must resolve it
+    // itself via WorkspaceRepo (a regression to req.raw.workspaceId would 401).
+    raw: {},
+  } as any;
+}
+
+function basic(email: string, password: string): string {
+  return 'Basic ' + Buffer.from(`${email}:${password}`).toString('base64');
+}
+
+beforeEach(() => {
+  jest.clearAllMocks();
+  // Silence the handler's logger.warn/error in negative-path tests.
+  jest.spyOn(Logger.prototype, 'warn').mockImplementation(() => undefined);
+  jest.spyOn(Logger.prototype, 'error').mockImplementation(() => undefined);
+});
+
+describe('GitHttpService.handle', () => {
+  it('fetch with valid creds resolves the workspace via the repo and dispatches WITHOUT the lock', async () => {
+    const built = build({ selfHosted: true });
+    const { reply, state } = fakeReply();
+    const req = fakeRequest({
+      url: '/git/space-1.git/info/refs?service=git-upload-pack',
+      method: 'GET',
+      authorization: basic('dev@example.com', 'pw'),
+    });
+
+    await built.service.handle(req, reply);
+
+    // The workspace came from WorkspaceRepo, NOT req.raw.workspaceId.
+    expect(built.workspaceRepo.findFirst).toHaveBeenCalledTimes(1);
+    expect(built.authService.verifyUserCredentials).toHaveBeenCalledWith(
+      { email: 'dev@example.com', password: 'pw' },
+      'ws-1',
+    );
+    expect(built.spaceRepo.findById).toHaveBeenCalledWith('space-1', 'ws-1');
+    // Read ability was evaluated.
+    expect(built.abilityCan).toHaveBeenCalledWith(
+      SpaceCaslAction.Read,
+      SpaceCaslSubject.Page,
+    );
+    // It proceeded: vault prepared, reply hijacked, backend ran directly.
+    expect(built.vaultRegistry.ensureServable).toHaveBeenCalledWith('space-1');
+    expect(state.hijacked).toBe(true);
+    expect(built.backend.run).toHaveBeenCalledTimes(1);
+    // A fetch must NOT take the push lock.
+    expect(built.orchestrator.ingestExternalPush).not.toHaveBeenCalled();
+  });
+
+  it('upload-pack ref advertisement is served HEAD-pinned via serveReadAdvertisement (bug #3)', async () => {
+    // GET info/refs?service=git-upload-pack carries the HEAD symref a clone reads
+    // for its default branch, so it must be served with HEAD pinned to `main`
+    // (under the lock) — not streamed raw — or a clone racing a mid-pull cycle
+    // would default to the read-only `docmost` mirror.
+    const built = build({ abilityCan: true });
+    const { reply } = fakeReply();
+    const req = fakeRequest({
+      url: '/git/space-1.git/info/refs?service=git-upload-pack',
+      method: 'GET',
+      authorization: basic('dev@example.com', 'pw'),
+    });
+
+    await built.service.handle(req, reply);
+
+    expect(built.orchestrator.serveReadAdvertisement).toHaveBeenCalledTimes(1);
+    expect(built.orchestrator.serveReadAdvertisement.mock.calls[0][0]).toBe(
+      'space-1',
+    );
+    // The wrapper still streams the backend (the mock runs the serve callback).
+    expect(built.backend.run).toHaveBeenCalledTimes(1);
+    expect(built.orchestrator.ingestExternalPush).not.toHaveBeenCalled();
+  });
+
+  it('a POST git-upload-pack pack fetch streams directly (no HEAD-pin needed, resolved by SHA)', async () => {
+    // The pack negotiation is object-SHA based; only the ref advertisement carries
+    // the HEAD symref, so the pack POST streams the backend directly (no lock).
+    const built = build({ abilityCan: true });
+    const { reply } = fakeReply();
+    const req = fakeRequest({
+      url: '/git/space-1.git/git-upload-pack',
+      method: 'POST',
+      authorization: basic('dev@example.com', 'pw'),
+    });
+
+    await built.service.handle(req, reply);
+
+    expect(built.orchestrator.serveReadAdvertisement).not.toHaveBeenCalled();
+    expect(built.backend.run).toHaveBeenCalledTimes(1);
+    expect(built.orchestrator.ingestExternalPush).not.toHaveBeenCalled();
+  });
+
+  it('cloud deployment resolves the workspace by the host subdomain', async () => {
+    const built = build({ selfHosted: false });
+    const { reply } = fakeReply();
+    const req = fakeRequest({
+      url: '/git/space-1.git/info/refs?service=git-upload-pack',
+      method: 'GET',
+      authorization: basic('dev@example.com', 'pw'),
+      host: 'acme.example.com',
+    });
+
+    await built.service.handle(req, reply);
+
+    expect(built.workspaceRepo.findByHostname).toHaveBeenCalledWith('acme');
+    expect(built.workspaceRepo.findFirst).not.toHaveBeenCalled();
+    expect(built.backend.run).toHaveBeenCalledTimes(1);
+  });
+
+  it('missing Basic credentials -> 401 with WWW-Authenticate', async () => {
+    const built = build();
+    const { reply, state } = fakeReply();
+    const req = fakeRequest({
+      url: '/git/space-1.git/info/refs?service=git-upload-pack',
+      method: 'GET',
+      // no Authorization header
+    });
+
+    await built.service.handle(req, reply);
+
+    expect(state.statusCode).toBe(401);
+    expect(state.headers['WWW-Authenticate']).toBe('Basic realm="gitmost"');
+    expect(built.backend.run).not.toHaveBeenCalled();
+    expect(built.authService.verifyUserCredentials).not.toHaveBeenCalled();
+  });
+
+  it('invalid Basic credentials -> 401 with WWW-Authenticate', async () => {
+    const built = build({ user: null }); // verifyUserCredentials throws 401
+    const { reply, state } = fakeReply();
+    const req = fakeRequest({
+      url: '/git/space-1.git/info/refs?service=git-upload-pack',
+      method: 'GET',
+      authorization: basic('dev@example.com', 'wrong'),
+    });
+
+    await built.service.handle(req, reply);
+
+    expect(state.statusCode).toBe(401);
+    expect(state.headers['WWW-Authenticate']).toBe('Basic realm="gitmost"');
+    expect(built.backend.run).not.toHaveBeenCalled();
+  });
+
+  it('a write by a Read-only user -> 403 (reader cannot push)', async () => {
+    const built = build({ abilityCan: false });
+    const { reply, state } = fakeReply();
+    const req = fakeRequest({
+      url: '/git/space-1.git/git-receive-pack',
+      method: 'POST',
+      authorization: basic('dev@example.com', 'pw'),
+    });
+
+    await built.service.handle(req, reply);
+
+    // The Manage ability was checked for a write and denied.
+    expect(built.abilityCan).toHaveBeenCalledWith(
+      SpaceCaslAction.Manage,
+      SpaceCaslSubject.Page,
+    );
+    expect(state.statusCode).toBe(403);
+    expect(built.orchestrator.ingestExternalPush).not.toHaveBeenCalled();
+    expect(built.backend.run).not.toHaveBeenCalled();
+  });
+
+  it('an authenticated NON-member of a git-sync space -> 404, NOT 403 (no existence leak)', async () => {
+    // createForUser throws NotFound when the user holds no role in the space (a
+    // non-member). The gate must return 404 — the SAME response a missing /
+    // sync-disabled space gives — so a 403↔404 difference cannot be used to
+    // brute-force which spaces exist / have git-sync enabled (the security fix).
+    const built = build({ abilityCan: false });
+    built.abilityFactory.createForUser.mockRejectedValue(
+      new NotFoundException('Space permissions not found'),
+    );
+    const { reply, state } = fakeReply();
+    const req = fakeRequest({
+      url: '/git/secret-space.git/info/refs?service=git-upload-pack',
+      method: 'GET',
+      authorization: basic('dev@example.com', 'pw'),
+    });
+
+    await built.service.handle(req, reply);
+
+    expect(built.abilityFactory.createForUser).toHaveBeenCalledTimes(1);
+    expect(state.statusCode).toBe(404);
+    expect(built.backend.run).not.toHaveBeenCalled();
+    expect(built.orchestrator.ingestExternalPush).not.toHaveBeenCalled();
+  });
+
+  it('a space that is not git-sync-enabled -> 404 (existence never revealed)', async () => {
+    const built = build({
+      space: { id: 'space-1', settings: { gitSync: { enabled: false } } },
+    });
+    const { reply, state } = fakeReply();
+    const req = fakeRequest({
+      url: '/git/space-1.git/info/refs?service=git-upload-pack',
+      method: 'GET',
+      authorization: basic('dev@example.com', 'pw'),
+    });
+
+    await built.service.handle(req, reply);
+
+    expect(state.statusCode).toBe(404);
+    // CASL is never even evaluated for a non-candidate space.
+    expect(built.abilityFactory.createForUser).not.toHaveBeenCalled();
+    expect(built.backend.run).not.toHaveBeenCalled();
+  });
+
+  it('git-sync globally disabled -> 404 even with valid creds', async () => {
+    const built = build({ gitSyncEnabled: false });
+    const { reply, state } = fakeReply();
+    const req = fakeRequest({
+      url: '/git/space-1.git/info/refs?service=git-upload-pack',
+      method: 'GET',
+      authorization: basic('dev@example.com', 'pw'),
+    });
+
+    await built.service.handle(req, reply);
+
+    expect(state.statusCode).toBe(404);
+    expect(built.backend.run).not.toHaveBeenCalled();
+  });
+
+  it('a valid write proceeds through the orchestrator (push takes the lock)', async () => {
+    const built = build({ abilityCan: true });
+    const { reply, state } = fakeReply();
+    const req = fakeRequest({
+      url: '/git/space-1.git/git-receive-pack',
+      method: 'POST',
+      authorization: basic('dev@example.com', 'pw'),
+    });
+
+    await built.service.handle(req, reply);
+
+    expect(built.abilityCan).toHaveBeenCalledWith(
+      SpaceCaslAction.Manage,
+      SpaceCaslSubject.Page,
+    );
+    expect(state.hijacked).toBe(true);
+    expect(built.orchestrator.ingestExternalPush).toHaveBeenCalledTimes(1);
+    const [spaceId, workspaceId] =
+      built.orchestrator.ingestExternalPush.mock.calls[0];
+    expect(spaceId).toBe('space-1');
+    expect(workspaceId).toBe('ws-1');
+  });
+
+  it('GET info/refs?service=git-receive-pack streams the backend WITHOUT a cycle/lock (so the follow-up POST never 503-collides)', async () => {
+    // A push is a TWO-request exchange: GET info/refs?service=git-receive-pack
+    // (ref advertisement) then POST git-receive-pack (the pack). The info/refs
+    // request is write-AUTHORIZED (push perms needed to see those refs) but is
+    // READ-ONLY — it must NOT run ingestExternalPush (a Docmost cycle under the
+    // per-space lock), or the immediately-following POST collides with the still-
+    // running cycle and deterministically 503s. It must just stream the backend.
+    const built = build({ abilityCan: true });
+    const { reply } = fakeReply();
+    const req = fakeRequest({
+      url: '/git/space-1.git/info/refs?service=git-receive-pack',
+      method: 'GET',
+      authorization: basic('dev@example.com', 'pw'),
+    });
+
+    await built.service.handle(req, reply);
+
+    // Authorized as a write (Manage), but executed as a plain stream.
+    expect(built.abilityCan).toHaveBeenCalledWith(
+      SpaceCaslAction.Manage,
+      SpaceCaslSubject.Page,
+    );
+    expect(built.orchestrator.ingestExternalPush).not.toHaveBeenCalled();
+    expect(built.backend.run).toHaveBeenCalledTimes(1);
+  });
+
+  it('a push that loses the lock -> 503 with Retry-After and a busy body (headers not written twice)', async () => {
+    const built = build({ abilityCan: true });
+    // The lock could not be acquired: the receive-pack closure never ran, so the
+    // response is still unwritten and the handler must answer 503 itself.
+    built.orchestrator.ingestExternalPush.mockRejectedValue(
+      new GitSyncLockHeldError('space-1'),
+    );
+    const { reply, state } = fakeReply();
+    const req = fakeRequest({
+      url: '/git/space-1.git/git-receive-pack',
+      method: 'POST',
+      authorization: basic('dev@example.com', 'pw'),
+    });
+
+    await built.service.handle(req, reply);
+
+    // It hijacked and went through the orchestrator (write path), but the lock
+    // was held so the backend never ran.
+    expect(state.hijacked).toBe(true);
+    expect(built.orchestrator.ingestExternalPush).toHaveBeenCalledTimes(1);
+    expect(built.backend.run).not.toHaveBeenCalled();
+
+    // 503 + Retry-After were written on the raw response (headersSent was false).
+    const raw = reply.raw as any;
+    expect(raw.statusCode).toBe(503);
+    expect(raw.setHeader).toHaveBeenCalledWith('Content-Type', 'text/plain');
+    expect(raw.setHeader).toHaveBeenCalledWith('Retry-After', '1');
+    // The body carries the busy/retry message and the response was ended once.
+    expect(raw.end).toHaveBeenCalledTimes(1);
+    expect(raw.end).toHaveBeenCalledWith('git-sync busy, retry');
+    // Exactly the two headers above were set — no double write of headers.
+    expect(raw.setHeader).toHaveBeenCalledTimes(2);
+  });
+
+  it('does NOT rewrite the 503 status/headers when the response is already sent', async () => {
+    const built = build({ abilityCan: true });
+    built.orchestrator.ingestExternalPush.mockRejectedValue(
+      new GitSyncLockHeldError('space-1'),
+    );
+    const { reply } = fakeReply();
+    // Simulate the (defensive) case where headers were already flushed: the
+    // handler must skip statusCode/setHeader and only end() the socket.
+    const raw = reply.raw as any;
+    raw.headersSent = true;
+    const req = fakeRequest({
+      url: '/git/space-1.git/git-receive-pack',
+      method: 'POST',
+      authorization: basic('dev@example.com', 'pw'),
+    });
+
+    await built.service.handle(req, reply);
+
+    // No header writes when headersSent is already true (no "headers already
+    // sent" double-write path), but the body/end still runs.
+    expect(raw.setHeader).not.toHaveBeenCalled();
+    expect(raw.statusCode).toBe(200); // untouched default from the fake
+    expect(raw.end).toHaveBeenCalledTimes(1);
+    expect(raw.end).toHaveBeenCalledWith('git-sync busy, retry');
+  });
+
+  it('an unresolvable workspace -> 401 (credentials cannot be validated without one)', async () => {
+    const built = build({ workspace: null });
+    const { reply, state } = fakeReply();
+    const req = fakeRequest({
+      url: '/git/space-1.git/info/refs?service=git-upload-pack',
+      method: 'GET',
+      authorization: basic('dev@example.com', 'pw'),
+    });
+
+    await built.service.handle(req, reply);
+
+    // Without a workspace we cannot run verifyUserCredentials, so credentials
+    // are not validated -> 401 (the 401-before-404 ordering is preserved: an
+    // unauthenticated request never reaches the space-existence 404).
+    expect(built.workspaceRepo.findFirst).toHaveBeenCalledTimes(1);
+    expect(built.authService.verifyUserCredentials).not.toHaveBeenCalled();
+    expect(state.statusCode).toBe(401);
+    expect(state.headers['WWW-Authenticate']).toBe('Basic realm="gitmost"');
+    expect(built.backend.run).not.toHaveBeenCalled();
+  });
+
+  // --- brute-force throttle (must-fix #1, mirrors the /mcp Basic limiter) -----
+  describe('HTTP-Basic brute-force throttle', () => {
+    /** A request with wrong credentials for the given email. */
+    const wrongCredReq = (email = 'dev@example.com') =>
+      fakeRequest({
+        url: '/git/space-1.git/info/refs?service=git-upload-pack',
+        method: 'GET',
+        authorization: basic(email, 'wrong'),
+      });
+
+    it('rejects the (threshold+1)-th failed attempt with 429 BEFORE bcrypt', async () => {
+      const built = build();
+      // Realistic credential failure: verifyUserCredentials throws the SAME
+      // UnauthorizedException(CREDENTIALS_MISMATCH_MESSAGE) production throws, so
+      // isCredentialsFailure matches and the reservation is KEPT (counted).
+      built.authService.verifyUserCredentials.mockRejectedValue(
+        new UnauthorizedException(CREDENTIALS_MISMATCH_MESSAGE),
+      );
+
+      // 5 failed attempts (threshold = 5): each runs the credential check -> 401.
+      for (let i = 0; i < 5; i++) {
+        const { reply, state } = fakeReply();
+        await built.service.handle(wrongCredReq(), reply);
+        expect(state.statusCode).toBe(401);
+      }
+      expect(built.authService.verifyUserCredentials).toHaveBeenCalledTimes(5);
+
+      // The 6th attempt is throttled: 429, Retry-After, and bcrypt is NOT run.
+      const { reply, state } = fakeReply();
+      await built.service.handle(wrongCredReq(), reply);
+      expect(state.statusCode).toBe(429);
+      expect(state.headers['Retry-After']).toBe('60');
+      expect(state.headers['WWW-Authenticate']).toBe('Basic realm="gitmost"');
+      // Still 5 — the 6th never reached verifyUserCredentials (pre-bcrypt reject).
+      expect(built.authService.verifyUserCredentials).toHaveBeenCalledTimes(5);
+      expect(built.backend.run).not.toHaveBeenCalled();
+
+      built.service.onModuleDestroy();
+    });
+
+    it('a successful auth resets the limiter so later attempts are not throttled', async () => {
+      const built = build();
+      const verify = built.authService.verifyUserCredentials;
+      // First 4 attempts fail (credential mismatch), then one SUCCEEDS.
+      verify
+        .mockRejectedValueOnce(new UnauthorizedException(CREDENTIALS_MISMATCH_MESSAGE))
+        .mockRejectedValueOnce(new UnauthorizedException(CREDENTIALS_MISMATCH_MESSAGE))
+        .mockRejectedValueOnce(new UnauthorizedException(CREDENTIALS_MISMATCH_MESSAGE))
+        .mockRejectedValueOnce(new UnauthorizedException(CREDENTIALS_MISMATCH_MESSAGE))
+        .mockResolvedValueOnce({ id: 'user-1', email: 'dev@example.com' });
+
+      for (let i = 0; i < 4; i++) {
+        const { reply } = fakeReply();
+        await built.service.handle(wrongCredReq(), reply);
+      }
+      // 5th attempt succeeds -> proceeds (not throttled) and clears the budget.
+      const okReply = fakeReply();
+      await built.service.handle(
+        fakeRequest({
+          url: '/git/space-1.git/info/refs?service=git-upload-pack',
+          method: 'GET',
+          authorization: basic('dev@example.com', 'right'),
+        }),
+        okReply.reply,
+      );
+      expect(okReply.state.hijacked).toBe(true); // proceeded to the backend
+
+      // After the reset, a fresh wrong attempt is evaluated (401), NOT a 429 —
+      // proving the per-IP/per-IP+email budget was cleared by the success.
+      verify.mockRejectedValueOnce(
+        new UnauthorizedException(CREDENTIALS_MISMATCH_MESSAGE),
+      );
+      const { reply, state } = fakeReply();
+      await built.service.handle(wrongCredReq(), reply);
+      expect(state.statusCode).toBe(401);
+
+      built.service.onModuleDestroy();
+    });
+
+    it('a non-credential error releases the reservation (does not burn the budget)', async () => {
+      const built = build();
+      // A DB error (not a credentials mismatch) must NOT count toward the limiter.
+      built.authService.verifyUserCredentials.mockRejectedValue(
+        new Error('db down'),
+      );
+
+      // 10 such failures — far beyond the threshold — must all be 401, never 429,
+      // because each releases its reservation.
+      for (let i = 0; i < 10; i++) {
+        const { reply, state } = fakeReply();
+        await built.service.handle(wrongCredReq(), reply);
+        expect(state.statusCode).toBe(401);
+      }
+      expect(built.authService.verifyUserCredentials).toHaveBeenCalledTimes(10);
+
+      built.service.onModuleDestroy();
+    });
+  });
+});

apps/server/src/integrations/git-sync/http/git-http.service.ts

@@ -0,0 +1,464 @@
+import {
+  Injectable,
+  Logger,
+  OnModuleDestroy,
+  UnauthorizedException,
+} from '@nestjs/common';
+import type { FastifyReply, FastifyRequest } from 'fastify';
+import { AuthService } from '../../../core/auth/services/auth.service';
+import SpaceAbilityFactory from '../../../core/casl/abilities/space-ability.factory';
+import {
+  SpaceCaslAction,
+  SpaceCaslSubject,
+} from '../../../core/casl/interfaces/space-ability.type';
+import { SpaceRepo } from '@docmost/db/repos/space/space.repo';
+import { WorkspaceRepo } from '@docmost/db/repos/workspace/workspace.repo';
+import { User } from '@docmost/db/types/entity.types';
+import {
+  parseBasicAuth,
+  FailedLoginLimiter,
+  clientIp,
+  isCredentialsFailure,
+} from '../../mcp/mcp-auth.helpers';
+import { resolveRequestWorkspace } from '../../../common/helpers/resolve-request-workspace';
+import { EnvironmentService } from '../../environment/environment.service';
+import { VaultRegistryService } from '../services/vault-registry.service';
+import {
+  GitSyncLockHeldError,
+  GitSyncOrchestrator,
+} from '../services/git-sync.orchestrator';
+import { GitHttpBackendService } from './git-http-backend.service';
+import {
+  decideGitHttpGate,
+  parseGitPath,
+  resolveServiceKind,
+  GitHttpServiceKind,
+} from './git-http.helpers';
+
+const WWW_AUTHENTICATE = 'Basic realm="gitmost"';
+
+/**
+ * The /git smart-HTTP host. Wires request parsing, the reused auth primitives
+ * (HTTP Basic -> AuthService.verifyUserCredentials), per-space gating
+ * (EnvironmentService flags + space.settings.gitSync.enabled), CASL authz
+ * (SpaceAbilityFactory), and dispatch to `git http-backend`:
+ *   - fetch  (read)  -> ensureServable then stream http-backend directly (no lock).
+ *   - push   (write) -> ensureServable then orchestrator.ingestExternalPush, which
+ *     runs the receive-pack under the space lock and then a Docmost cycle.
+ *
+ * Mounted at the ROOT (`/git/...`) by a raw Fastify route in main.ts (the global
+ * `/api` prefix does not apply). Never logs the password or Authorization header.
+ */
+@Injectable()
+export class GitHttpService implements OnModuleDestroy {
+  private readonly logger = new Logger(GitHttpService.name);
+
+  /**
+   * In-process brute-force speed bump for the /git HTTP-Basic path. The raw
+   * `/git/*` Fastify route bypasses the Nest pipeline (so ThrottlerGuard, which is
+   * only on controllers, never runs) and there is no fastify rate-limit plugin, so
+   * without this `verifyUserCredentials` (bcrypt) would run unthrottled on every
+   * request once GIT_SYNC_HTTP_ENABLED is on. Mirrors the /mcp Basic path EXACTLY
+   * (FailedLoginLimiter, same 5/60s thresholds, the same per-IP / per-IP+email /
+   * global-per-email keys) so the two auth seams cannot diverge. A speed bump, not
+   * a hard boundary (in-process, per replica).
+   */
+  private readonly failedLogins = new FailedLoginLimiter(5, 60_000);
+  /** Periodic sweep to bound limiter memory (mirrors McpService / mcp http.ts). */
+  private readonly sweepIntervalMs = 60_000;
+  private readonly sweepTimer: NodeJS.Timeout;
+
+  constructor(
+    private readonly environmentService: EnvironmentService,
+    private readonly authService: AuthService,
+    private readonly spaceRepo: SpaceRepo,
+    private readonly workspaceRepo: WorkspaceRepo,
+    private readonly spaceAbilityFactory: SpaceAbilityFactory,
+    private readonly vaultRegistry: VaultRegistryService,
+    private readonly orchestrator: GitSyncOrchestrator,
+    private readonly backend: GitHttpBackendService,
+  ) {
+    this.sweepTimer = setInterval(() => {
+      try {
+        this.failedLogins.sweep();
+      } catch (err) {
+        this.logger.error('git-http failed-login limiter sweep failed', err as Error);
+      }
+    }, this.sweepIntervalMs);
+    // Never keep the event loop alive solely for the sweep timer.
+    this.sweepTimer.unref?.();
+  }
+
+  onModuleDestroy(): void {
+    clearInterval(this.sweepTimer);
+  }
+
+  /**
+   * Resolve the workspace for a /git request the SAME way DomainMiddleware does,
+   * because Nest middleware does NOT run for this raw root-mounted route (it is
+   * registered under the global '/api' router), so `req.raw.workspaceId` is never
+   * populated here. Delegates to the shared `resolveRequestWorkspace` helper (the
+   * SAME self-hosted/cloud branch DomainMiddleware uses) and returns just the id:
+   *   - self-hosted (single workspace) -> workspaceRepo.findFirst();
+   *   - cloud (multi-tenant)           -> resolve by the host-header subdomain.
+   * Returns null when no workspace resolves; the gate then 404s (after the
+   * 401-before-404 credential check encoded in decideGitHttpGate).
+   */
+  private async resolveWorkspaceId(req: FastifyRequest): Promise<string | null> {
+    try {
+      // Same self-hosted/cloud resolution DomainMiddleware uses — shared so the
+      // branch cannot drift between the two call sites.
+      const workspace = await resolveRequestWorkspace(
+        this.environmentService,
+        this.workspaceRepo,
+        this.headerValue(req.headers['host']),
+      );
+      return workspace?.id ?? null;
+    } catch (err) {
+      // A DB error resolving the workspace must not leak details; treat as
+      // unresolvable (the gate will 404, unless creds are missing -> 401 first).
+      this.logger.warn(
+        `git-http: workspace resolution error: ${
+          err instanceof Error ? err.message : String(err)
+        }`,
+      );
+    }
+    return null;
+  }
+
+  /**
+   * Handle one `/git/<spaceId>.git/<subpath>` request. `rest` is the path AFTER
+   * the `/git/` prefix (no query string). The Fastify reply is hijacked before
+   * any streaming so the binary CGI body is written directly to the raw socket.
+   */
+  async handle(req: FastifyRequest, reply: FastifyReply): Promise<void> {
+    const rawReq = req.raw;
+    const rawRes = reply.raw;
+
+    // --- parse the URL into spaceId + subpath -------------------------------
+    const rest = this.extractRest(req.url);
+    const parsedPath = rest === null ? null : parseGitPath(rest);
+
+    // --- resolve the requested git service kind (read vs write) -------------
+    const service =
+      typeof req.query === 'object' && req.query !== null
+        ? (req.query as Record<string, string | undefined>).service
+        : undefined;
+    const serviceKind: GitHttpServiceKind | null = parsedPath
+      ? resolveServiceKind({
+          method: req.method,
+          subpath: parsedPath.subpath,
+          service,
+        })
+      : null;
+
+    // --- authenticate (HTTP Basic) ------------------------------------------
+    const authHeader = req.headers['authorization'];
+    const basic = parseBasicAuth(
+      Array.isArray(authHeader) ? authHeader[0] : authHeader,
+    );
+    // Resolve the workspace ourselves — DomainMiddleware does NOT run for this
+    // raw root route, so `req.raw.workspaceId` is never set (see resolver doc).
+    const workspaceId: string | null = await this.resolveWorkspaceId(req);
+
+    let user: User | undefined;
+    let credentialsValid = false;
+    let throttled = false;
+    if (basic && workspaceId) {
+      // Brute-force speed bump, mirroring the /mcp Basic path EXACTLY. Reserve
+      // ALL three keys ATOMICALLY and BEFORE bcrypt (tryReserve folds the check
+      // and the increment into one synchronous step), so the (threshold+1)-th
+      // attempt is rejected before verifyUserCredentials/bcrypt ever runs and
+      // concurrent attempts for one email cannot all observe count=0. The
+      // reservation IS the recorded failure: a genuine credential failure leaves
+      // it in place, a SUCCESS clears it (reset), a non-credential error releases
+      // it (so it cannot burn a victim's budget).
+      const emailLc = basic.email.toLowerCase();
+      const ip = clientIp(req);
+      const ipKey = `ip:${ip}`;
+      const ipEmailKey = `ip-email:${ip}:${emailLc}`;
+      // GLOBAL per-email backstop (no IP): the only key that survives IP / XFF
+      // rotation, so it is the real account-brute defense (see mcp-auth.helpers).
+      const emailKey = `email:${emailLc}`;
+      const ipOk = this.failedLogins.tryReserve(ipKey);
+      const ipEmailOk = this.failedLogins.tryReserve(ipEmailKey);
+      const emailOk = this.failedLogins.tryReserve(emailKey);
+      if (!ipOk || !ipEmailOk || !emailOk) {
+        // Blocked: release only the keys we actually reserved this call so an
+        // already-throttled request does not over-charge keys still under budget
+        // (matches the /mcp reserve model). Do NOT run bcrypt.
+        if (ipOk) this.failedLogins.release(ipKey);
+        if (ipEmailOk) this.failedLogins.release(ipEmailKey);
+        if (emailOk) this.failedLogins.release(emailKey);
+        throttled = true;
+      } else {
+        try {
+          user = await this.authService.verifyUserCredentials(
+            { email: basic.email, password: basic.password },
+            workspaceId,
+          );
+          credentialsValid = true;
+          // Success: clear the per-IP and per-IP+email budgets fully; for the
+          // GLOBAL per-email key only release the one increment THIS request took
+          // (do not reset() it, or a victim's own success would wipe a parallel
+          // attacker's accumulated failures for that email — same rule as /mcp).
+          this.failedLogins.reset(ipKey);
+          this.failedLogins.reset(ipEmailKey);
+          this.failedLogins.release(emailKey);
+        } catch (err) {
+          // Only a genuine credentials failure (wrong email/password) keeps the
+          // reservation (it IS the recorded failure). Any other error — DB error,
+          // etc. — is NOT a password-guess signal, so release the reservation so
+          // it cannot burn a victim's limiter budget. credentialsValid stays
+          // false either way (the gate then 401s).
+          if (!isCredentialsFailure(err)) {
+            this.failedLogins.release(ipKey);
+            this.failedLogins.release(ipEmailKey);
+            this.failedLogins.release(emailKey);
+          }
+          if (!(err instanceof UnauthorizedException)) {
+            // A non-credential failure (e.g. DB error): treat as invalid creds
+            // for the gate (a 401), and log without leaking the password/header.
+            this.logger.warn(
+              `git-http: credential check error: ${
+                err instanceof Error ? err.message : String(err)
+              }`,
+            );
+          }
+          credentialsValid = false;
+        }
+      }
+    }
+
+    // Brute-force throttle tripped: reject BEFORE the gate (and before any space
+    // lookup), so a throttled attacker gets a uniform 429 with no bcrypt and no
+    // existence signal. WWW-Authenticate is still sent so a legitimate client
+    // re-prompts after the window.
+    if (throttled) {
+      reply
+        .header('WWW-Authenticate', WWW_AUTHENTICATE)
+        .header('Retry-After', '60')
+        .status(429)
+        .send('Too many failed authentication attempts. Try again later.');
+      return;
+    }
+
+    // --- resolve the space + per-space gating + CASL ------------------------
+    let spaceExists = false;
+    let spaceGitSyncEnabled = false;
+    let spaceId: string | undefined;
+    // The user has SOME role in the space. SECURITY: a non-member must get the
+    // SAME 404 a missing/disabled space gets — never a 403 — or the 403↔404 split
+    // would let any authenticated user brute-force slugs to learn which spaces
+    // exist / have sync enabled (the leak this gate's contract forbids). 403 is
+    // reserved for a MEMBER who lacks the required role (existence already known).
+    let userIsSpaceMember = false;
+    let permissionGranted = false;
+    if (credentialsValid && user && workspaceId && parsedPath && serviceKind) {
+      const space = await this.spaceRepo.findById(
+        parsedPath.spaceId,
+        workspaceId,
+      );
+      if (space) {
+        spaceExists = true;
+        spaceId = space.id;
+        spaceGitSyncEnabled =
+          (space.settings as any)?.gitSync?.enabled === true;
+
+        // Only evaluate CASL when the space is actually a sync candidate — an
+        // unrelated space stays a 404 (existence is never revealed).
+        if (spaceGitSyncEnabled) {
+          try {
+            const ability = await this.spaceAbilityFactory.createForUser(
+              user,
+              space.id,
+            );
+            // createForUser RESOLVED -> the user holds a role in this space (it
+            // throws NotFound for a non-member). Record membership BEFORE the
+            // permission check: a member lacking the role -> 403; a non-member ->
+            // 404 (handled by the gate via userIsSpaceMember=false below).
+            userIsSpaceMember = true;
+            const action =
+              serviceKind === 'write'
+                ? SpaceCaslAction.Manage
+                : SpaceCaslAction.Read;
+            permissionGranted = ability.can(action, SpaceCaslSubject.Page);
+          } catch {
+            // createForUser throws NotFoundException when the user has no role in
+            // the space (a non-member). Leave userIsSpaceMember=false so the gate
+            // returns 404, NOT 403 — a non-member must not be able to tell this
+            // space apart from a non-existent one. (Any other error also falls
+            // here and is treated as non-member -> 404, the safe default that
+            // never reveals existence.)
+            userIsSpaceMember = false;
+            permissionGranted = false;
+          }
+        }
+      }
+    }
+
+    // --- the gate decision (pure) -------------------------------------------
+    const decision = decideGitHttpGate({
+      hasCredentials: Boolean(basic),
+      credentialsValid,
+      serviceKind,
+      gitSyncEnabled: this.environmentService.isGitSyncEnabled(),
+      gitHttpEnabled: this.environmentService.isGitSyncHttpEnabled(),
+      spaceExists,
+      spaceGitSyncEnabled,
+      userIsSpaceMember,
+      permissionGranted,
+    });
+
+    if (decision.kind === 'unauthorized') {
+      reply
+        .header('WWW-Authenticate', WWW_AUTHENTICATE)
+        .status(401)
+        .send('Authentication required');
+      return;
+    }
+    if (decision.kind === 'bad-request') {
+      reply.status(400).send('Bad request');
+      return;
+    }
+    if (decision.kind === 'not-found') {
+      reply.status(404).send('Not found');
+      return;
+    }
+    if (decision.kind === 'forbidden') {
+      reply.status(403).send('Forbidden');
+      return;
+    }
+
+    // decision.kind === 'proceed' — guaranteed below (narrowing for TS).
+    if (!parsedPath || !serviceKind || !spaceId || !user || !workspaceId) {
+      // Defensive: 'proceed' implies these are set, but keep TS + runtime safe.
+      reply.status(500).send('Internal server error');
+      return;
+    }
+
+    // --- dispatch to git http-backend ---------------------------------------
+    const backendRequest = {
+      spaceId,
+      subpath: parsedPath.subpath,
+      method: req.method,
+      queryString: this.extractQueryString(req.url),
+      contentType: this.headerValue(req.headers['content-type']) ?? '',
+      gitProtocol: this.headerValue(req.headers['git-protocol']),
+      remoteUser: user.email,
+    };
+
+    try {
+      // Idempotently make the vault servable (repo + receive/upload config).
+      await this.vaultRegistry.ensureServable(spaceId);
+    } catch (err) {
+      this.logger.error(
+        `git-http: failed to prepare vault for space ${spaceId}: ${
+          err instanceof Error ? err.message : String(err)
+        }`,
+      );
+      if (!reply.sent) reply.status(500).send('Internal server error');
+      return;
+    }
+
+    // Hijack the reply so the backend can stream the raw (possibly binary) CGI
+    // response directly to the socket (mirrors the MCP transport pattern).
+    reply.hijack();
+
+    // Only the ACTUAL pack-receiving write (POST git-receive-pack) runs under the
+    // space lock + a Docmost cycle. Everything else streams the http-backend
+    // directly with NO lock and NO cycle: a fetch/clone (read), AND the
+    // write-AUTHORIZED but READ-ONLY ref advertisement
+    // (GET info/refs?service=git-receive-pack). Running a cycle on info/refs is
+    // both wasteful and HARMFUL — it holds the per-space lock, so the push's
+    // immediately-following POST git-receive-pack collides with it and 503s
+    // (a deterministic push failure). Authz already happened above via the gate.
+    const isReceivePack =
+      req.method === 'POST' && parsedPath.subpath === 'git-receive-pack';
+    if (serviceKind === 'read' || !isReceivePack) {
+      // The clone's default branch comes from the HEAD symref advertised by the
+      // upload-pack ref advertisement (or a dumb `GET HEAD`). The engine
+      // transiently checks out the read-only `docmost` mirror mid-cycle, so serve
+      // THAT advertisement with HEAD pinned to `main` under the per-space lock so
+      // a clone never defaults to `docmost` (bug #3). Pack streaming and every
+      // other read are resolved by object SHA and need no pin, so they stream
+      // directly (no lock) as before.
+      const isReadAdvertise =
+        req.method === 'GET' &&
+        ((parsedPath.subpath === 'info/refs' &&
+          service === 'git-upload-pack') ||
+          parsedPath.subpath === 'HEAD');
+      if (isReadAdvertise) {
+        await this.orchestrator.serveReadAdvertisement(spaceId, () =>
+          this.backend.run(backendRequest, rawReq, rawRes),
+        );
+      } else {
+        await this.backend.run(backendRequest, rawReq, rawRes);
+      }
+      return;
+    }
+
+    // Push: run the receive-pack under the space lock, then a Docmost cycle.
+    try {
+      await this.orchestrator.ingestExternalPush(
+        spaceId,
+        workspaceId,
+        // The lock's lost-lock signal is threaded into the backend so the
+        // receive-pack child is killed if the lock lapses mid-write (warning #3).
+        (signal) => this.backend.run(backendRequest, rawReq, rawRes, signal),
+      );
+    } catch (err) {
+      if (err instanceof GitSyncLockHeldError) {
+        // The lock could not be acquired and the receive-pack never ran, so the
+        // response is still unwritten — answer 503 so git retries.
+        if (!rawRes.headersSent) {
+          rawRes.statusCode = 503;
+          rawRes.setHeader('Content-Type', 'text/plain');
+          rawRes.setHeader('Retry-After', '1');
+        }
+        try {
+          rawRes.end('git-sync busy, retry');
+        } catch {
+          /* ignore */
+        }
+        return;
+      }
+      // Any other error: the receive-pack closure handles its own response, so
+      // we only log here and make sure the socket is closed.
+      this.logger.error(
+        `git-http: push ingestion error for space ${spaceId}: ${
+          err instanceof Error ? err.message : String(err)
+        }`,
+      );
+      try {
+        if (!rawRes.writableEnded) rawRes.end();
+      } catch {
+        /* ignore */
+      }
+    }
+  }
+
+  /** Normalise a possibly-array header value to its first string. */
+  private headerValue(value: string | string[] | undefined): string | undefined {
+    if (Array.isArray(value)) return value[0];
+    return value;
+  }
+
+  /**
+   * Extract the part of the URL AFTER `/git/` and BEFORE the query string.
+   * Returns null when the URL is not under `/git/`.
+   */
+  private extractRest(url: string): string | null {
+    const qIdx = url.indexOf('?');
+    const pathname = qIdx === -1 ? url : url.slice(0, qIdx);
+    const prefix = '/git/';
+    if (!pathname.startsWith(prefix)) return null;
+    return pathname.slice(prefix.length);
+  }
+
+  /** The raw query string without the leading '?', or '' when none. */
+  private extractQueryString(url: string): string {
+    const qIdx = url.indexOf('?');
+    return qIdx === -1 ? '' : url.slice(qIdx + 1);
+  }
+}

apps/server/src/integrations/git-sync/listeners/page-change.listener.spec.ts

@@ -0,0 +1,252 @@
+// Unit tests for the event-driven git-sync trigger. The orchestrator
+// and page repo are hand-built mocks; the debounce coalescing is exercised with
+// jest fake timers. We assert the gate, the loop-guard (anti-echo), the
+// missing-page short-circuit, the heterogeneous event-shape id resolution, the
+// debounce collapse, and that errors are swallowed + logged.
+import { Logger } from '@nestjs/common';
+import { PageChangeListener } from './page-change.listener';
+
+type AnyMock = jest.Mock;
+
+interface Built {
+  listener: PageChangeListener;
+  env: { isGitSyncEnabled: AnyMock; getGitSyncDebounceMs: AnyMock };
+  orchestrator: { runOnce: AnyMock };
+  pageRepo: { findById: AnyMock };
+}
+
+function build(opts: { enabled?: boolean; debounceMs?: number } = {}): Built {
+  const { enabled = true, debounceMs = 2000 } = opts;
+  const env = {
+    isGitSyncEnabled: jest.fn(() => enabled),
+    getGitSyncDebounceMs: jest.fn(() => debounceMs),
+  };
+  const orchestrator = { runOnce: jest.fn(async () => undefined) };
+  const pageRepo = { findById: jest.fn() };
+
+  const listener = new PageChangeListener(
+    env as any,
+    orchestrator as any,
+    pageRepo as any,
+  );
+  return { listener, env, orchestrator, pageRepo };
+}
+
+beforeEach(() => {
+  jest.clearAllMocks();
+});
+
+describe('PageChangeListener', () => {
+  describe('gate', () => {
+    it('does nothing when git-sync is disabled (no findById, no schedule)', async () => {
+      const { listener, orchestrator, pageRepo } = build({ enabled: false });
+      await listener.handlePageEvent({ pageId: 'p1', workspaceId: 'ws-1' });
+      expect(pageRepo.findById).not.toHaveBeenCalled();
+      expect(orchestrator.runOnce).not.toHaveBeenCalled();
+    });
+  });
+
+  describe('loop-guard (anti-echo)', () => {
+    it("does NOT schedule a cycle when the page row's source is 'git-sync'", async () => {
+      jest.useFakeTimers();
+      try {
+        const { listener, orchestrator, pageRepo } = build();
+        pageRepo.findById.mockResolvedValue({
+          id: 'p1',
+          spaceId: 'space-1',
+          workspaceId: 'ws-1',
+          lastUpdatedSource: 'git-sync',
+        });
+        await listener.handlePageEvent({ pageId: 'p1', workspaceId: 'ws-1' });
+        jest.runOnlyPendingTimers();
+        expect(orchestrator.runOnce).not.toHaveBeenCalled();
+      } finally {
+        jest.useRealTimers();
+      }
+    });
+
+    it('schedules exactly one cycle for a normal (non-git-sync) source', async () => {
+      jest.useFakeTimers();
+      try {
+        const { listener, orchestrator, pageRepo } = build();
+        pageRepo.findById.mockResolvedValue({
+          id: 'p1',
+          spaceId: 'space-1',
+          workspaceId: 'ws-1',
+          lastUpdatedSource: 'user',
+        });
+        await listener.handlePageEvent({ pageId: 'p1', workspaceId: 'ws-1' });
+        jest.runOnlyPendingTimers();
+        expect(orchestrator.runOnce).toHaveBeenCalledTimes(1);
+        expect(orchestrator.runOnce).toHaveBeenCalledWith('space-1', 'ws-1');
+      } finally {
+        jest.useRealTimers();
+      }
+    });
+  });
+
+  describe('missing page', () => {
+    it('does not schedule when findById returns null/undefined', async () => {
+      jest.useFakeTimers();
+      try {
+        const { listener, orchestrator, pageRepo } = build();
+        pageRepo.findById.mockResolvedValue(undefined);
+        await listener.handlePageEvent({ pageId: 'p1', workspaceId: 'ws-1' });
+        jest.runOnlyPendingTimers();
+        expect(orchestrator.runOnce).not.toHaveBeenCalled();
+      } finally {
+        jest.useRealTimers();
+      }
+    });
+  });
+
+  describe('spaceId/workspaceId resolution', () => {
+    // The page row used to fill in any ids the event omits.
+    const pageRow = {
+      id: 'p1',
+      spaceId: 'row-space',
+      workspaceId: 'row-ws',
+      lastUpdatedSource: 'user',
+    };
+
+    async function resolve(event: Record<string, unknown>) {
+      jest.useFakeTimers();
+      try {
+        const { listener, orchestrator, pageRepo } = build();
+        pageRepo.findById.mockResolvedValue(pageRow);
+        await listener.handlePageEvent(event as any);
+        jest.runOnlyPendingTimers();
+        return { orchestrator, pageRepo };
+      } finally {
+        jest.useRealTimers();
+      }
+    }
+
+    it("resolves pageId + event.spaceId + event.workspaceId", async () => {
+      const { orchestrator, pageRepo } = await resolve({
+        pageId: 'p1',
+        spaceId: 'evt-space',
+        workspaceId: 'evt-ws',
+      });
+      expect(pageRepo.findById).toHaveBeenCalledWith('p1', { includeContent: false });
+      expect(orchestrator.runOnce).toHaveBeenCalledWith('evt-space', 'evt-ws');
+    });
+
+    it('resolves pageId from pageIds[0]', async () => {
+      const { orchestrator, pageRepo } = await resolve({
+        pageIds: ['p1', 'p2'],
+        spaceId: 'evt-space',
+        workspaceId: 'evt-ws',
+      });
+      expect(pageRepo.findById).toHaveBeenCalledWith('p1', { includeContent: false });
+      expect(orchestrator.runOnce).toHaveBeenCalledWith('evt-space', 'evt-ws');
+    });
+
+    it('resolves pageId + spaceId from pages[]', async () => {
+      const { orchestrator } = await resolve({
+        pages: [{ id: 'p1', spaceId: 'pages-space' }],
+        workspaceId: 'evt-ws',
+      });
+      expect(orchestrator.runOnce).toHaveBeenCalledWith('pages-space', 'evt-ws');
+    });
+
+    it('resolves pageId + spaceId from node', async () => {
+      const { orchestrator } = await resolve({
+        node: { id: 'p1', spaceId: 'node-space' },
+        workspaceId: 'evt-ws',
+      });
+      expect(orchestrator.runOnce).toHaveBeenCalledWith('node-space', 'evt-ws');
+    });
+
+    it('falls back to the fetched page row when the event omits spaceId/workspaceId', async () => {
+      const { orchestrator } = await resolve({ pageId: 'p1' });
+      // No spaceId/workspaceId on the event -> use the page row's values.
+      expect(orchestrator.runOnce).toHaveBeenCalledWith('row-space', 'row-ws');
+    });
+  });
+
+  describe('debounce coalescing', () => {
+    it('collapses a burst of N events for one space into exactly one runOnce', async () => {
+      jest.useFakeTimers();
+      try {
+        const { listener, orchestrator, pageRepo } = build({ debounceMs: 500 });
+        pageRepo.findById.mockResolvedValue({
+          id: 'p1',
+          spaceId: 'space-1',
+          workspaceId: 'ws-1',
+          lastUpdatedSource: 'user',
+        });
+
+        // Fire a burst of 5 events; await each so its findById promise settles
+        // and schedule() runs before the next event resets the timer.
+        for (let i = 0; i < 5; i++) {
+          await listener.handlePageEvent({ pageId: 'p1', workspaceId: 'ws-1' });
+        }
+
+        // Nothing fired yet (still within the debounce window).
+        expect(orchestrator.runOnce).not.toHaveBeenCalled();
+
+        // Advance past the debounce window: the coalesced cycle fires once.
+        jest.advanceTimersByTime(500);
+        expect(orchestrator.runOnce).toHaveBeenCalledTimes(1);
+        expect(orchestrator.runOnce).toHaveBeenCalledWith('space-1', 'ws-1');
+      } finally {
+        jest.useRealTimers();
+      }
+    });
+  });
+
+  describe('onModuleDestroy', () => {
+    it('clears every pending debounce timer and empties the map', async () => {
+      jest.useFakeTimers();
+      const clearSpy = jest.spyOn(global, 'clearTimeout');
+      try {
+        const { listener, orchestrator, pageRepo } = build({ debounceMs: 500 });
+        pageRepo.findById.mockResolvedValue({
+          id: 'p1',
+          spaceId: 'space-1',
+          workspaceId: 'ws-1',
+          lastUpdatedSource: 'user',
+        });
+
+        // Schedule a pending cycle, then tear the module down before it fires.
+        await listener.handlePageEvent({ pageId: 'p1', workspaceId: 'ws-1' });
+        clearSpy.mockClear(); // ignore any clears done by schedule() itself
+
+        listener.onModuleDestroy();
+
+        // The pending timer was cleared and the map drained, so advancing past
+        // the debounce window fires NO cycle.
+        expect(clearSpy).toHaveBeenCalledTimes(1);
+        expect((listener as any).debounce.size).toBe(0);
+        jest.advanceTimersByTime(500);
+        expect(orchestrator.runOnce).not.toHaveBeenCalled();
+      } finally {
+        clearSpy.mockRestore();
+        jest.useRealTimers();
+      }
+    });
+  });
+
+  describe('error swallowing', () => {
+    it('does not throw and logs a warning when findById throws', async () => {
+      const warnSpy = jest
+        .spyOn(Logger.prototype, 'warn')
+        .mockImplementation(() => undefined);
+      try {
+        const { listener, orchestrator, pageRepo } = build();
+        pageRepo.findById.mockRejectedValue(new Error('db down'));
+
+        await expect(
+          listener.handlePageEvent({ pageId: 'p1', workspaceId: 'ws-1' }),
+        ).resolves.toBeUndefined();
+
+        expect(warnSpy).toHaveBeenCalledTimes(1);
+        expect(String(warnSpy.mock.calls[0][0])).toContain('db down');
+        expect(orchestrator.runOnce).not.toHaveBeenCalled();
+      } finally {
+        warnSpy.mockRestore();
+      }
+    });
+  });
+});

apps/server/src/integrations/git-sync/listeners/page-change.listener.ts

@@ -0,0 +1,168 @@
+import { Injectable, Logger, OnModuleDestroy } from '@nestjs/common';
+import { OnEvent } from '@nestjs/event-emitter';
+import { PageRepo } from '@docmost/db/repos/page/page.repo';
+import { EnvironmentService } from '../../environment/environment.service';
+import { GitSyncOrchestrator } from '../services/git-sync.orchestrator';
+import { GIT_SYNC_PAGE_EVENTS } from '../git-sync.constants';
+
+/**
+ * Shape of the page domain events the listener consumes. Different emit sites
+ * carry different optional fields (page.repo `PageEvent`, `PageMovedEvent`,
+ * etc.), so this is the intersection we read: a `pageIds` list / single `pageId`,
+ * the `workspaceId`, and an OPTIONAL `spaceId` (present only on some events). When
+ * `spaceId` is absent we resolve it from the page row.
+ */
+interface PageEventLike {
+  pageIds?: string[];
+  pageId?: string;
+  workspaceId?: string;
+  spaceId?: string;
+  pages?: { id: string; spaceId: string }[];
+  node?: { id: string; spaceId: string };
+}
+
+/**
+ * Event-driven trigger for the git-sync control plane. Subscribes to
+ * the page lifecycle events and, for an enabled space, schedules a DEBOUNCED
+ * `orchestrator.runOnce(spaceId, workspaceId)` — coalescing a burst of edits into
+ * a single cycle per space.
+ *
+ * Loop-guard (best-effort): an event whose page row already reads
+ * `lastUpdatedSource === 'git-sync'` is the orchestrator's OWN write, so we skip
+ * it to avoid a write -> event -> sync echo. The guard ALWAYS runs (the page row
+ * is fetched for every event, structural ones included). This is the cheap first
+ * guard; the full bodyHash + updatedAt loop-guard (consuming the push side's
+ * `PushedPageRecord`) is a later hardening step — noted, not built here.
+ *
+ * KNOWN OVER-SKIP (latency, NOT data loss): the guard keys ONLY on
+ * `lastUpdatedSource`, and a user MOVE / RENAME / DELETE does NOT change that
+ * column (only body writes stamp it). So a genuine user move/rename/delete of a
+ * page whose BODY was last written by git-sync still reads
+ * `lastUpdatedSource === 'git-sync'` and is dropped on this fast debounced path.
+ * No change is lost: the poll-safety interval (~GIT_SYNC_POLL_INTERVAL_MS, default
+ * 15s) re-enumerates the space and reconciles it — the only cost is up to one poll
+ * interval of extra latency before that structural change reaches git. The
+ * bodyHash+updatedAt loop-guard above would close this gap precisely.
+ */
+@Injectable()
+export class PageChangeListener implements OnModuleDestroy {
+  private readonly logger = new Logger(PageChangeListener.name);
+  // spaceId -> pending debounce timer. The cycle closes over its own
+  // workspaceId, so the timer handle is all the map needs to track.
+  private readonly debounce = new Map<string, NodeJS.Timeout>();
+
+  constructor(
+    private readonly environmentService: EnvironmentService,
+    private readonly orchestrator: GitSyncOrchestrator,
+    private readonly pageRepo: PageRepo,
+  ) {}
+
+  /**
+   * One handler bound to ALL git-sync page events (the array form of `@OnEvent`).
+   * Fetches the page row once to apply the loop-guard (unconditionally) and to
+   * resolve the page's space + workspace, then schedules the debounced cycle.
+   */
+  @OnEvent(GIT_SYNC_PAGE_EVENTS as unknown as string[])
+  async handlePageEvent(event: PageEventLike): Promise<void> {
+    if (!this.environmentService.isGitSyncEnabled()) return;
+
+    try {
+      const pageId = this.firstPageId(event);
+      if (!pageId) return;
+
+      // The loop-guard MUST always run — even structural events that already
+      // carry spaceId+workspaceId could be the orchestrator's OWN write (it stamps
+      // lastUpdatedSource='git-sync' on create/update/move/rename + body writes).
+      // So ALWAYS fetch the page row: it gives us the loop-guard source AND fills
+      // in any missing space/workspace in a single read. A missing page
+      // (hard-deleted) is ignored.
+      const page = await this.pageRepo.findById(pageId, {
+        includeContent: false,
+      });
+      if (!page) return;
+
+      // Loop-guard: skip our own writes to avoid a write -> event -> sync echo
+      // (best-effort). Applies unconditionally now. NOTE this also over-skips a
+      // user move/rename/delete of a page whose BODY was last written by git-sync
+      // (those structural ops don't touch lastUpdatedSource) — that change is not
+      // lost, just deferred to the ~15s poll backstop (see class docstring).
+      if (page.lastUpdatedSource === 'git-sync') return;
+
+      // Prefer ids carried on the event; fall back to the row we already fetched.
+      const spaceId = this.eventSpaceId(event, pageId) ?? page.spaceId;
+      const workspaceId = event.workspaceId ?? page.workspaceId;
+
+      if (!spaceId || !workspaceId) return;
+      this.schedule(spaceId, workspaceId);
+    } catch (err) {
+      this.logger.warn(
+        `git-sync: failed to handle page event: ${
+          err instanceof Error ? err.message : String(err)
+        }`,
+      );
+    }
+  }
+
+  /** Pull the first affected pageId out of the heterogeneous event shapes. */
+  private firstPageId(event: PageEventLike): string | undefined {
+    return (
+      event.pageId ??
+      event.pageIds?.[0] ??
+      event.pages?.[0]?.id ??
+      event.node?.id
+    );
+  }
+
+  /** A spaceId carried directly on the event, for the given pageId if scoped. */
+  private eventSpaceId(
+    event: PageEventLike,
+    pageId: string,
+  ): string | undefined {
+    if (event.spaceId) return event.spaceId;
+    const fromPages = event.pages?.find((p) => p.id === pageId)?.spaceId;
+    if (fromPages) return fromPages;
+    if (event.node?.id === pageId) return event.node.spaceId;
+    return undefined;
+  }
+
+  /**
+   * On shutdown, clear every pending debounce timer so a not-yet-fired cycle does
+   * not run against a tearing-down module. The timers are already `.unref()`'d (so
+   * they never block process exit), but clearing them also drops the dangling
+   * references and prevents a late `runOnce` from firing post-destroy.
+   */
+  onModuleDestroy(): void {
+    for (const timer of this.debounce.values()) {
+      clearTimeout(timer);
+    }
+    this.debounce.clear();
+  }
+
+  /**
+   * Debounce per space: a new event resets the timer so a burst collapses into a
+   * single cycle. On fire, `runOnce` is enqueued (it internally serializes via the
+   * in-process mutex + Redis lock, so a still-running cycle is simply skipped and
+   * the next event reschedules).
+   */
+  private schedule(spaceId: string, workspaceId: string): void {
+    const existing = this.debounce.get(spaceId);
+    if (existing) clearTimeout(existing);
+
+    const timer = setTimeout(() => {
+      this.debounce.delete(spaceId);
+      void this.orchestrator
+        .runOnce(spaceId, workspaceId)
+        .catch((err) =>
+          this.logger.error(
+            `git-sync: debounced cycle for space ${spaceId} failed: ${
+              err instanceof Error ? err.message : String(err)
+            }`,
+          ),
+        );
+    }, this.environmentService.getGitSyncDebounceMs());
+
+    // Do not keep the event loop alive solely for a pending sync.
+    timer.unref?.();
+    this.debounce.set(spaceId, timer);
+  }
+}