Merge remote-tracking branch 'gitea/develop' into feat/git-sync-2

Two-phase scheme instead of the sequential gate: the build job runs in
parallel with test/e2e jobs and only warms the buildx GHA cache
(push:false, cache-to mode=max); a new publish job (needs: test,
e2e-server, e2e-mcp, build) rebuilds from the warm cache (near-instant
on hit, full rebuild on eviction — same as the old sequential timing)
and pushes :develop. GHCR login moved to publish; build-args blocks are
kept textually identical between the two jobs so the cache hits.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.env.example

@@ -202,6 +202,13 @@ MCP_DOCMOST_PASSWORD=
 # Default 900000 (15 min).
 # AI_MCP_CALL_TIMEOUT_MS=900000
 
+# Deferred tool loading for the in-app AI chat (#332). Default ON: the agent sees
+# a compact <tool_catalog> and only CORE tools + a loadTools meta-tool are active
+# each step; deferred tools (the fat/rare ones + all external MCP tools) load on
+# demand. Set AI_CHAT_DEFERRED_TOOLS=false to restore the old "all tools always
+# active" behavior.
+# AI_CHAT_DEFERRED_TOOLS=true
+
 # --- Anonymous public-share AI assistant ---
 # Opt-in per workspace (AI settings -> "public share assistant"; off by default).
 # When enabled, anonymous visitors of a published share can ask an AI about that
@@ -235,3 +242,45 @@ 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=
+#
+# SCAFFOLDING for the DEFERRED remote-push feature (SPEC §7) — NOT yet
+# implemented and currently INERT. The vendored sync engine does not consume
+# this value anywhere (git push to a remote is deferred), so setting it has NO
+# effect today: vaults remain local-only regardless. It is validated and carried
+# only so the wiring is ready for when remote push lands. The intended future
+# shape is a per-space URL template where the literal "{spaceId}" is substituted
+# per space (e.g. git@host:vault-{spaceId}.git).
+# 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/develop.yml

@@ -18,12 +18,48 @@ env:
   IMAGE: ghcr.io/vvzvlad/gitmost
 
 jobs:
-  # Run the reusable test suite first so a failing test blocks the image build.
+  # Run the reusable test suite. Together with the e2e jobs below it gates the
+  # publish job (the image push), not the build itself — build runs in parallel.
   test:
     uses: ./.github/workflows/test.yml
 
+  # Runs in parallel with the test/e2e jobs and only warms the buildx cache
+  # (GHA cache, scope develop-amd64). No push happens here — the publish job
+  # below is the only one that pushes the image.
   build:
-    needs: test
+    runs-on: ubuntu-latest
+    timeout-minutes: 30
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Resolve version
+        id: version
+        run: echo "value=$(git describe --tags --always)" >> "$GITHUB_OUTPUT"
+
+      - name: Build develop image (warm cache, no push)
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          platforms: linux/amd64
+          build-args: |
+            APP_VERSION=${{ steps.version.outputs.value }}
+            AI_AGENT_ROLES_CATALOG_URL=https://raw.githubusercontent.com/vvzvlad/gitmost/develop/agent-roles-catalog
+          push: false
+          cache-from: type=gha,scope=develop-amd64
+          cache-to: type=gha,scope=develop-amd64,mode=max,ignore-error=true
+
+  # The gate: rebuilds from the cache the build job just wrote (near-instant on
+  # a cache hit; worst case — cache eviction — a full rebuild, which matches the
+  # old sequential timing) and pushes :develop only when unit tests AND both
+  # e2e suites AND the build are green.
+  publish:
+    needs: [test, e2e-server, e2e-mcp, build]
     runs-on: ubuntu-latest
     timeout-minutes: 30
     steps:
@@ -57,13 +93,10 @@ jobs:
           push: true
           tags: ${{ env.IMAGE }}:develop
           cache-from: type=gha,scope=develop-amd64
-          cache-to: type=gha,scope=develop-amd64,mode=max,ignore-error=true
 
-  # e2e jobs run on every develop push but DO NOT gate the build/publish above:
-  # `build` stays `needs: test` only, so the :develop image still ships even if
-  # e2e fails. A failing e2e job turns the run red and triggers GitHub's email
-  # to the pusher — that red run + email is the intended notification, not a
-  # deploy block.
+  # e2e jobs gate the publish (image push), not the build: the :develop image
+  # is pushed only when unit tests AND both e2e suites pass (publish.needs
+  # lists them all).
   e2e-server:
     runs-on: ubuntu-latest
     # Hard cap: the full-AppModule e2e leaks open handles and hung jest to the 6h max.
@@ -124,9 +157,7 @@ jobs:
       - name: Run server e2e
         run: pnpm --filter ./apps/server test:e2e
 
-  # Same rationale as e2e-server: this job is intentionally NOT in
-  # `build.needs`. Deploy of the :develop image must not be blocked by e2e;
-  # a red run plus GitHub's email to the pusher is the notification mechanism.
+  # Gates the publish too — see the comment above e2e-server.
   e2e-mcp:
     runs-on: ubuntu-latest
     timeout-minutes: 20

.github/workflows/test.yml

@@ -72,6 +72,22 @@ jobs:
       - name: Build editor-ext
         run: pnpm --filter @docmost/editor-ext build
 
+      # @docmost/prosemirror-markdown is the shared converter (#293/#326); its
+      # build/ is gitignored, and plain `pnpm -r test` does NOT honour nx
+      # `dependsOn: ^build`, so its consumers (mcp `pretest: tsc`, git-sync vitest
+      # typecheck) fail with TS2307 Cannot find module '@docmost/prosemirror-markdown'
+      # unless it is built first. Build it BEFORE git-sync/mcp (which import it).
+      - name: Build prosemirror-markdown
+        run: pnpm --filter @docmost/prosemirror-markdown 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 (git-sync's runtime consumer lands on this branch,
+      # #119). 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

@@ -4,11 +4,17 @@
 data
 # compiled output
 /dist
-node_modules/
+/node_modules
+# workspace package node_modules (pnpm symlinks — never commit; they bake
+# machine-local store paths).
+packages/*/node_modules/
 
-# git-sync compiled output (built in CI/Docker via `pnpm build`, never committed,
-# so src/ and prod can never silently diverge).
+# Compiled package output: build/ is gitignored for every workspace package
+# (built in CI/Docker via `pnpm build`, never committed, so src/ and prod can
+# never silently diverge). Private packages are rebuilt at deploy.
 packages/git-sync/build/
+packages/prosemirror-markdown/build/
+packages/mcp/build/
 
 # Logs
 logs

AGENTS.md

@@ -193,14 +193,16 @@ authenticated in-process, so no `tea`/`curl` and no keychain lookup are needed.
 
 ## 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 |
 | --- | --- | --- | --- |
 | `apps/server` | `server` | NestJS 11 + Fastify, Kysely (Postgres), Redis | Backend API, collaboration, AI |
 | `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/mcp` | `@docmost/mcp` | MCP SDK, Tiptap, Yjs | Standalone MCP server, also bundled into the server at `/mcp`. Consumes the shared converter/schema from `@docmost/prosemirror-markdown` (#293) — it no longer carries its own vendored converter/schema copy |
+| `packages/prosemirror-markdown` | `@docmost/prosemirror-markdown` | Tiptap, marked, jsdom | The single, canonical ProseMirror↔Markdown converter + Docmost schema mirror (#293). Consumed by `mcp` and `git-sync`; there is exactly ONE copy of the converter now |
+| `packages/git-sync` | `@docmost/git-sync` | Tiptap/ProseMirror, Yjs, git | The two-way Docmost↔git Markdown sync **engine** (vault layout, git orchestration, reconcile). Consumes the ProseMirror↔Markdown converter from `@docmost/prosemirror-markdown` (#293) — no longer carries its own converter copy. Bundled into the server (loaded over the ESM bridge), built in CI and the Dockerfile. |
 
 `build` targets are Nx-cached and dependency-ordered (`dependsOn: ["^build"]`), so `editor-ext` builds before the apps. `nx.json` sets `affected.defaultBase: main`.
 
@@ -262,8 +264,10 @@ 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`). `GET /api/sb/:id` (the anonymous blob-sandbox read route) is listed in that preHandler's `excludedPaths`, so it is exempt from workspace resolution and carries no session auth at all (its capability is the unguessable UUID + TTL + TLS) — unlike `/api/files/public/...`, which still resolves a workspace and requires a workspace-bound attachment JWT. 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.
 
@@ -279,10 +283,16 @@ The API server is a Fastify app with a global `/api` prefix (`main.ts` excludes
    - `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. The ProseMirror↔Markdown converter and its Docmost schema mirror now live in a SINGLE package, `@docmost/prosemirror-markdown` (#293), consumed by both `mcp` and `git-sync` — do NOT reintroduce a per-package copy. `editor-ext` is the upstream source of the Tiptap schema; the package's `docmost-schema.ts` mirrors it and a serializer-contract test (`packages/prosemirror-markdown/test/serializer-contract.test.ts`) guards the boundary (every schema node must have a converter case), so a drift surfaces as a failing test rather than silent divergence.
 - 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`.
 
@@ -293,7 +303,7 @@ Vite SPA. Code is organized by feature under `apps/client/src/features/*` (mirro
 - The version string shown in the UI comes from `APP_VERSION` (CI/Docker) or `git describe --tags --always` (local), resolved in `vite.config.ts` — not from `package.json`.
 - Server TS config is permissive (`noImplicitAny: false`, `strictNullChecks: false`, `no-explicit-any` lint disabled). Follow the existing relaxed style rather than tightening types broadly.
 - Dependency versions are heavily pinned via `pnpm.overrides` and `pnpm.patchedDependencies` (`scimmy`, `yjs`) in the root `package.json`. Don't bump pinned/patched deps casually; the patches and overrides exist for compatibility/security reasons.
-- **Adding/renaming/removing an MCP tool requires updating `SERVER_INSTRUCTIONS`** in `packages/mcp/src/index.ts` — the intent-routing guide MCP clients receive on initialize. This applies both to inline `server.registerTool(...)` calls in `index.ts` and to specs in `packages/mcp/src/tool-specs.ts`. Enforced by `packages/mcp/test/unit/server-instructions.test.mjs`, which fails when a registered tool is not mentioned in the guide (deliberate opt-outs go into its `EXCEPTIONS` list). Remember `packages/mcp/build/` is committed — rebuild after editing.
+- **Adding/renaming/removing an MCP tool requires updating `SERVER_INSTRUCTIONS`** in `packages/mcp/src/index.ts` — the intent-routing guide MCP clients receive on initialize. This applies both to inline `server.registerTool(...)` calls in `index.ts` and to specs in `packages/mcp/src/tool-specs.ts`. Enforced by `packages/mcp/test/unit/server-instructions.test.mjs`, which fails when a registered tool is not mentioned in the guide (deliberate opt-outs go into its `EXCEPTIONS` list). `packages/mcp/build/` is gitignored and rebuilt in CI/Docker via `pnpm build` (same convention as `git-sync`/`prosemirror-markdown`) — never commit it; rebuild locally after editing to run the tests.
 
 ## CI / release
 

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)
 - **Place several images side by side in a row.** A new "Inline (side by
   side)" alignment mode in the image bubble menu renders consecutive inline
   images as a row that wraps onto the next line on narrow screens. The row is

Dockerfile

@@ -5,6 +5,13 @@ RUN npm install -g pnpm@10.4.0
 
 FROM base AS builder
 
+# re2 (packages/mcp) always compiles from source under pnpm (the prebuilt-binary
+# download cannot identify the GitHub repo), so node-gyp needs python3/make/g++.
+# This stage is discarded, so the toolchain can stay installed.
+RUN apt-get update \
+  && apt-get install -y --no-install-recommends python3 make g++ \
+  && rm -rf /var/lib/apt/lists/*
+
 WORKDIR /app
 
 COPY . .
@@ -17,8 +24,9 @@ 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 +46,20 @@ 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
+# @docmost/prosemirror-markdown is the shared converter (#293/#326). Both mcp and
+# git-sync depend on it (workspace:*) and load it at runtime, so the built package +
+# its manifest must be shipped or the prod install resolves a broken workspace
+# symlink and every consumer dies with ERR_MODULE_NOT_FOUND.
+COPY --from=builder /app/packages/prosemirror-markdown/build /app/packages/prosemirror-markdown/build
+COPY --from=builder /app/packages/prosemirror-markdown/package.json /app/packages/prosemirror-markdown/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). This branch (#119) is where git-sync gains its runtime consumer.
+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
@@ -49,9 +71,16 @@ COPY --from=builder /app/patches /app/patches
 
 RUN chown -R node:node /app
 
-USER node
+# Toolchain is needed transiently to compile re2 during the prod install; install
+# and purge it in one layer to keep the final image slim. The install itself runs
+# as the node user via su to keep node_modules ownership without a costly chown layer.
+RUN apt-get update \
+  && apt-get install -y --no-install-recommends python3 make g++ \
+  && su node -c "pnpm install --frozen-lockfile --prod" \
+  && apt-get purge -y --auto-remove python3 make g++ \
+  && rm -rf /var/lib/apt/lists/*
 
-RUN pnpm install --frozen-lockfile --prod
+USER node
 
 RUN mkdir -p /app/data/storage
 

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

@@ -128,7 +128,7 @@ roles:
       - Don't fabricate confirmations. If you can't verify, honestly mark [Unverified] or [Unverifiable].
 
       HOW TO LEAVE COMMENTS
-      You 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. Give the verdict, the correction (if any), and the source. For an [Incorrect] verdict, ALWAYS attach the ready correction as a suggested replacement (the `suggestedText` parameter): since you found the correct value in the sources, propose the ready fix right away instead of merely describing the error. The replacement is the exact new text for the selected fragment, plain text with no markup; the author applies it with one click instead of retyping the fragment. The selected fragment must occur exactly once in the text; if it isn't unique, extend the selection with surrounding context. Do not attach a replacement to [Unverified], [Unverifiable], or [Opinion] verdicts. Tag severity:
+      You 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. Give the verdict, the correction (if any), and the source. For an [Incorrect] verdict, ALWAYS attach the ready correction as a suggested replacement (the `suggestedText` parameter): since you found the correct value in the sources, propose the ready fix right away instead of merely describing the error. The replacement is the exact new text for the selected fragment, plain text with no markup; the author applies it with one click instead of retyping the fragment. The selected fragment must occur exactly once in the text; if it isn't unique, extend the selection with surrounding context. When a figure, name, term, or version to check recurs across the page, use search_in_page to find every occurrence in one call first, then place a targeted comment per hit instead of reading block by block. Do not attach a replacement to [Unverified], [Unverifiable], or [Opinion] verdicts. Tag severity:
       - [Critical] — a factual error, especially in numbers, names, or quotes, or a claim that risks misinformation.
       - [Major] — a doubtful or unconfirmed claim that needs a source.
       - [Minor] — a small correction, or false precision worth rounding or confirming.
@@ -169,7 +169,7 @@ roles:
       - Don't make substantive changes. Edits are minimal and mechanical.
 
       HOW TO WORK
-      Go through the whole text from start to finish in a single pass. Flag EVERY violation, including all repeat occurrences of the same error and minor items tagged [Minor] — don't stop at the first few or the most conspicuous. Don't summarize instead of marking up: until you've reached the end of the document, the job isn't done. One run covers the whole text, not just "the most important".
+      Go through the whole text from start to finish in a single pass. Flag EVERY violation, including all repeat occurrences of the same error and minor items tagged [Minor] — don't stop at the first few or the most conspicuous. Don't summarize instead of marking up: until you've reached the end of the document, the job isn't done. One run covers the whole text, not just "the most important". For a systematic issue that recurs — straight quotes, a hyphen used as a dash, an inconsistent unit or spelling — use search_in_page to list every occurrence in one call first, then leave a targeted comment (with its replacement) on each hit, instead of scanning block by block.
 
       HOW TO LEAVE COMMENTS
       You don't edit the text directly. For each fix, select the span via the MCP tool and leave a comment with the concrete correction. Attach a suggested replacement to every fix (the `suggestedText` parameter): the exact corrected text for the selected fragment, plain text with no markup — the author applies it with one click. The selected fragment must occur exactly once in the text; if it isn't unique, extend the selection with surrounding context. Do NOT leave summary notes like "throughout, replace X with Y" or "make the units/quotes/spelling consistent": such a comment can't be applied with a button. If the same error occurs in several places, walk EVERY occurrence and leave a separate targeted comment with its own replacement on each — ten targeted fixes instead of one blanket note. The only exception is a note that genuinely cannot be expressed as a replacement of a concrete fragment; leave those rare cases as an ordinary comment without a replacement. Tag severity:

agent-roles-catalog/bundles/editorial/ru.yaml

@@ -128,7 +128,7 @@ roles:
       - Не выдумываешь подтверждения. Если не можешь проверить — честно ставь [Не проверено] или [Непроверяемо].
 
       КАК ОСТАВЛЯТЬ ЗАМЕЧАНИЯ
-      Ты не редактируешь текст напрямую. Для каждого проблемного утверждения (ошибка, сомнение, непроверяемость) через MCP-инструмент выдели фрагмент и оставь комментарий; на верные факты комментарии не оставляй. В комментарии дай вердикт, исправление (если нужно) и источник. К вердикту [Неверно] всегда прикладывай готовое исправление как предложение-замену (параметр `suggestedText`): раз ты нашёл по источникам верное значение — сразу предлагай готовую правку, а не только описывай ошибку. Замена — это точный новый текст взамен выделенного фрагмента, обычным текстом без разметки; автор применит её одной кнопкой, не переписывая фрагмент вручную. Выделенный фрагмент должен встречаться в тексте ровно один раз; если он не уникален, расширь выделение контекстом. К вердиктам [Не проверено], [Непроверяемо] и [Это мнение] замену не прикладывай. Помечай важность:
+      Ты не редактируешь текст напрямую. Для каждого проблемного утверждения (ошибка, сомнение, непроверяемость) через MCP-инструмент выдели фрагмент и оставь комментарий; на верные факты комментарии не оставляй. В комментарии дай вердикт, исправление (если нужно) и источник. К вердикту [Неверно] всегда прикладывай готовое исправление как предложение-замену (параметр `suggestedText`): раз ты нашёл по источникам верное значение — сразу предлагай готовую правку, а не только описывай ошибку. Замена — это точный новый текст взамен выделенного фрагмента, обычным текстом без разметки; автор применит её одной кнопкой, не переписывая фрагмент вручную. Выделенный фрагмент должен встречаться в тексте ровно один раз; если он не уникален, расширь выделение контекстом. Когда проверяемая цифра, имя, термин или версия встречается по тексту несколько раз, сначала одним вызовом search_in_page найди все вхождения, а затем ставь целевой комментарий на каждое — не читая страницу поблочно. К вердиктам [Не проверено], [Непроверяемо] и [Это мнение] замену не прикладывай. Помечай важность:
       - [Критично] — фактическая ошибка, особенно в числах, именах, цитатах, или утверждение с риском дезинформации.
       - [Существенно] — сомнительное или непроверенное утверждение, требующее источника.
       - [Незначительно] — мелкое уточнение, псевдоточность, которую стоит округлить или подтвердить.
@@ -170,7 +170,7 @@ roles:
       - Не вносишь содержательных изменений. Правки — минимальные и механические.
 
       КАК РАБОТАТЬ
-      Пройди весь текст от начала до конца за один проход. Помечай КАЖДОЕ нарушение, включая все повторные вхождения одной и той же ошибки и мелочи с меткой [Незначительно], — не ограничивайся первыми несколькими или самыми заметными. Не подводи итог вместо разбора: пока не дошёл до конца документа, работа не закончена. Один прогон покрывает весь текст, а не «самое важное».
+      Пройди весь текст от начала до конца за один проход. Помечай КАЖДОЕ нарушение, включая все повторные вхождения одной и той же ошибки и мелочи с меткой [Незначительно], — не ограничивайся первыми несколькими или самыми заметными. Не подводи итог вместо разбора: пока не дошёл до конца документа, работа не закончена. Один прогон покрывает весь текст, а не «самое важное». Для систематической ошибки, которая повторяется — прямые кавычки, «е» вместо «ё», дефис вместо тире, неединообразная единица или написание, — сначала одним вызовом search_in_page получи все вхождения, а затем оставь на каждом целевой комментарий с заменой, вместо поблочного просмотра.
 
       КАК ОСТАВЛЯТЬ ЗАМЕЧАНИЯ
       Ты не редактируешь текст напрямую. Для каждой правки через MCP-инструмент выдели фрагмент и оставь комментарий с конкретным исправлением. К каждой правке прикладывай предложение-замену (параметр `suggestedText`): точный исправленный текст взамен выделенного фрагмента, обычным текстом без разметки — автор применит его одной кнопкой. Выделенный фрагмент должен встречаться в тексте ровно один раз; если он не уникален, расширь выделение контекстом. НЕ оставляй сводных замечаний вида «во всём тексте заменить X на Y» или «привести единицы/кавычки/написание к единообразию»: такой комментарий нельзя применить кнопкой. Если одна и та же ошибка встречается в нескольких местах, обойди КАЖДОЕ вхождение и оставь на нём отдельный целевой комментарий со своей заменой — десять точечных правок вместо одной общей. Единственное исключение — замечание, которое в принципе невозможно выразить заменой конкретного фрагмента; такие редкие случаи оставляй обычным комментарием без замены. Помечай важность:

agent-roles-catalog/index.yaml

@@ -16,9 +16,9 @@ bundles:
       - slug: line-editor
         version: 4
       - slug: fact-checker
-        version: 5
+        version: 6
       - slug: proofreader
-        version: 7
+        version: 8
       - slug: narrator
         version: 2
   - id: research

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

@@ -1,7 +1,7 @@
 {
   "fact-checker": {
-    "version": 5,
-    "hash": "d7769872968109a1ccfb58d71bc3f3564a750b91766156f59031762848de4f24"
+    "version": 6,
+    "hash": "6bb22a9e5a5079b5cb287b5b26addbd36b9afeb7c9508287dcad9343fc53d685"
   },
   "line-editor": {
     "version": 4,
@@ -12,8 +12,8 @@
     "hash": "66fe653003b4f63ef3c3a5c5c48552fe47daeefffc16907c37c35f0e8da98851"
   },
   "proofreader": {
-    "version": 7,
-    "hash": "fdf8e0a443fa3c4102095e024146401363629a3f9015fb938c7bac2642825e56"
+    "version": 8,
+    "hash": "cef39fed321779631ddd1077fcba53399adf0e48b301df281c71eb042610900d"
   },
   "researcher": {
     "version": 1,

apps/client/package.json

@@ -82,6 +82,7 @@
     "@types/react": "18.3.12",
     "@types/react-dom": "18.3.1",
     "@vitejs/plugin-react": "6.0.1",
+    "@vitest/coverage-v8": "4.1.6",
     "eslint": "9.28.0",
     "eslint-plugin-react": "7.37.5",
     "eslint-plugin-react-hooks": "7.0.1",

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

@@ -1222,8 +1222,12 @@
   "Commented": "Commented",
   "Resolved comment": "Resolved comment",
   "Ran tool {{name}}": "Ran tool {{name}}",
+  "AI-agent": "AI-agent",
   "AI agent «{{role}}» on behalf of {{person}}": "AI agent «{{role}}» on behalf of {{person}}",
   "AI agent {{name}}": "AI agent {{name}}",
+  "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.",
@@ -1248,6 +1252,10 @@
   "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",
@@ -1382,5 +1390,8 @@
   "Applied": "Applied",
   "Suggestion applied": "Suggestion applied",
   "Failed to apply suggestion": "Failed to apply suggestion",
-  "The commented text changed since this suggestion was made; it was not applied.": "The commented text changed since this suggestion was made; it was not applied."
+  "The commented text changed since this suggestion was made; it was not applied.": "The commented text changed since this suggestion was made; it was not applied.",
+  "Dismiss": "Dismiss",
+  "Suggestion dismissed": "Suggestion dismissed",
+  "Failed to dismiss suggestion": "Failed to dismiss suggestion"
 }

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

@@ -737,6 +737,7 @@
   "Deleted successfully": "Успешно удалено",
   "AI agent «{{role}}» on behalf of {{person}}": "AI-агент «{{role}}» от имени {{person}}",
   "AI agent {{name}}": "AI-агент {{name}}",
+  "Edited by AI agent on behalf of {{name}}": "Отредактировано AI-агентом от имени {{name}}",
   "Failed to delete chat": "Не удалось удалить чат",
   "Failed to rename chat": "Не удалось переименовать чат",
   "Failed": "Ошибка",
@@ -1245,5 +1246,8 @@
   "Applied": "Применено",
   "Suggestion applied": "Предложение применено",
   "Failed to apply suggestion": "Не удалось применить предложение",
-  "The commented text changed since this suggestion was made; it was not applied.": "Прокомментированный текст изменился после создания предложения; оно не было применено."
+  "The commented text changed since this suggestion was made; it was not applied.": "Прокомментированный текст изменился после создания предложения; оно не было применено.",
+  "Dismiss": "Не применять",
+  "Suggestion dismissed": "Предложение отклонено",
+  "Failed to dismiss suggestion": "Не удалось отклонить предложение"
 }

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/ai-chat/components/chat-thread.test.tsx

@@ -1,5 +1,5 @@
 import { describe, it, expect, beforeEach, vi } from "vitest";
-import { render, screen, fireEvent, act } from "@testing-library/react";
+import { render, screen, fireEvent, act, cleanup } from "@testing-library/react";
 import { MantineProvider } from "@mantine/core";
 
 // Shared, hoisted mock state so the @ai-sdk/react and "ai" module mocks (hoisted
@@ -140,3 +140,91 @@ describe("ChatThread — send now (#198)", () => {
     expect(prep({ messages: [], body: {} }).body.interrupted).toBe(false);
   });
 });
+
+// The turn-end decision lives in the `onFinish` handler: given the terminal
+// outcome of a turn (`isAbort` / `isDisconnect` / `isError`, or none = clean),
+// it decides whether to CONTINUE (flush the next queued message) or END (leave
+// the queue intact for the user), and which stop notice — if any — to show.
+// `sendNow` is exercised above; these tests pin down the plain outcomes.
+describe("ChatThread — turn-end decision (onFinish)", () => {
+  beforeEach(() => {
+    h.state.status = "streaming";
+    h.state.onFinish = null;
+    h.state.sendMessage.mockClear();
+    h.state.stop.mockClear();
+    h.state.transport = null;
+  });
+
+  // Drive a fresh onFinish with the given terminal flags after queueing a
+  // message, and report both what the parent was told and whether the queue was
+  // flushed (a resend to the sendMessage spy).
+  function finishWith(flags: {
+    isAbort?: boolean;
+    isDisconnect?: boolean;
+    isError?: boolean;
+  }) {
+    // Tear down any prior render so the loop-driven "every outcome" case does
+    // not leave duplicate queue buttons in the DOM.
+    cleanup();
+    h.state.sendMessage.mockClear();
+    const { onTurnFinished } = renderThread();
+    // Populate the queue while the turn is streaming.
+    fireEvent.click(screen.getByTestId("queue-btn"));
+    act(() => {
+      h.state.onFinish?.({
+        message: { id: "a", role: "assistant", parts: [] },
+        isAbort: false,
+        isDisconnect: false,
+        isError: false,
+        ...flags,
+      });
+    });
+    return { onTurnFinished };
+  }
+
+  it("CONTINUES — flushes the next queued message on a clean finish", () => {
+    finishWith({});
+    // Clean finish (no terminal flag): the queued message is auto-sent.
+    expect(h.state.sendMessage).toHaveBeenCalledWith({ text: "queued text" });
+    // A clean finish shows no stop notice.
+    expect(screen.queryByText("Response stopped.")).toBeNull();
+  });
+
+  it("ENDS — keeps the queue intact on a user abort and shows the stopped notice", () => {
+    finishWith({ isAbort: true });
+    // A plain Stop (not the sendNow interrupt path) must NOT auto-resend: the
+    // queue is preserved for the user to decide.
+    expect(h.state.sendMessage).not.toHaveBeenCalled();
+    expect(screen.getByText("Response stopped.")).toBeTruthy();
+  });
+
+  it("ENDS — keeps the queue intact on a disconnect and shows the connection-lost notice", () => {
+    finishWith({ isDisconnect: true });
+    expect(h.state.sendMessage).not.toHaveBeenCalled();
+    expect(
+      screen.getByText("Connection lost — the answer was interrupted."),
+    ).toBeTruthy();
+  });
+
+  it("ENDS — keeps the queue intact on a stream error (no auto-retry, no stopped notice)", () => {
+    finishWith({ isError: true });
+    // Blindly retrying after a failure would be wrong; the queue is left alone.
+    expect(h.state.sendMessage).not.toHaveBeenCalled();
+    // isError clears the neutral notice (the error banner covers this case).
+    expect(screen.queryByText("Response stopped.")).toBeNull();
+  });
+
+  it("notifies the parent on EVERY terminal outcome", () => {
+    // The chat-list refresh / new-chat id adoption must run on success and on
+    // every failure path alike.
+    for (const flags of [
+      {},
+      { isAbort: true },
+      { isDisconnect: true },
+      { isError: true },
+    ]) {
+      const { onTurnFinished } = finishWith(flags);
+      expect(onTurnFinished).toHaveBeenCalled();
+    }
+  });
+});

apps/client/src/features/comment/components/comment-content-view.test.tsx

@@ -0,0 +1,250 @@
+import { describe, it, expect, vi } from "vitest";
+import { render, screen } from "@testing-library/react";
+import { MantineProvider } from "@mantine/core";
+import { MemoryRouter } from "react-router-dom";
+
+// matchMedia (read by MantineProvider) is stubbed globally in vitest.setup.ts.
+
+// The fallback path renders the full TipTap editor; stub it so we can assert the
+// safety valve fired without pulling in the editor stack.
+vi.mock("@/features/comment/components/comment-editor", () => ({
+  default: () => <div data-testid="comment-editor-fallback" />,
+}));
+
+// Mention rendering hits react-query; stub the page/share queries so the mention
+// case renders in isolation.
+vi.mock("@/features/page/queries/page-query.ts", () => ({
+  usePageQuery: () => ({ data: undefined, isLoading: false, isError: false }),
+}));
+vi.mock("@/features/share/queries/share-query.ts", () => ({
+  useSharePageQuery: () => ({ data: undefined }),
+}));
+
+import { CommentContentView } from "./comment-content-view";
+
+function renderView(content: string | object) {
+  return render(
+    <MantineProvider>
+      <MemoryRouter>
+        <CommentContentView content={content} />
+      </MemoryRouter>
+    </MantineProvider>,
+  );
+}
+
+const doc = (content: any[]) => JSON.stringify({ type: "doc", content });
+const para = (content: any[]) => ({ type: "paragraph", content });
+const text = (t: string, marks?: any[]) => ({ type: "text", text: t, marks });
+
+describe("CommentContentView", () => {
+  it("renders paragraphs as <p> with text", () => {
+    const { container } = renderView(doc([para([text("Hello world")])]));
+    expect(screen.getByText("Hello world")).toBeDefined();
+    expect(container.querySelector("p")).not.toBeNull();
+  });
+
+  it("reproduces the read-only CommentEditor DOM nesting for CSS parity", () => {
+    const { container } = renderView(doc([para([text("x")])]));
+    // outer .commentEditor > .ProseMirror (module) > .ProseMirror (global) > p
+    const globalPm = container.querySelector("div.ProseMirror > p");
+    expect(globalPm).not.toBeNull();
+  });
+
+  it("renders the bold mark as <strong>", () => {
+    const { container } = renderView(
+      doc([para([text("bold", [{ type: "bold" }])])]),
+    );
+    const el = container.querySelector("strong");
+    expect(el?.textContent).toBe("bold");
+  });
+
+  it("renders the italic mark as <em>", () => {
+    const { container } = renderView(
+      doc([para([text("it", [{ type: "italic" }])])]),
+    );
+    expect(container.querySelector("em")?.textContent).toBe("it");
+  });
+
+  it("renders the strike mark as <s>", () => {
+    const { container } = renderView(
+      doc([para([text("st", [{ type: "strike" }])])]),
+    );
+    expect(container.querySelector("s")?.textContent).toBe("st");
+  });
+
+  it("renders the underline mark as <u> (not the editor fallback)", () => {
+    const { container } = renderView(
+      doc([para([text("un", [{ type: "underline" }])])]),
+    );
+    expect(container.querySelector("u")?.textContent).toBe("un");
+    // Underline is a supported mark, so no degrade to the editor fallback.
+    expect(screen.queryByTestId("comment-editor-fallback")).toBeNull();
+  });
+
+  it("renders the code mark as <code>", () => {
+    const { container } = renderView(
+      doc([para([text("co", [{ type: "code" }])])]),
+    );
+    expect(container.querySelector("code")?.textContent).toBe("co");
+  });
+
+  it("renders the link mark as an anchor with safe rel/target", () => {
+    const { container } = renderView(
+      doc([
+        para([
+          text("click", [
+            { type: "link", attrs: { href: "https://example.com" } },
+          ]),
+        ]),
+      ]),
+    );
+    const a = container.querySelector("a");
+    expect(a?.getAttribute("href")).toBe("https://example.com");
+    expect(a?.getAttribute("target")).toBe("_blank");
+    expect(a?.getAttribute("rel")).toBe("noopener noreferrer nofollow");
+    expect(a?.textContent).toBe("click");
+  });
+
+  it("neutralizes a javascript: link href (stored XSS) while keeping the text", () => {
+    const { container } = renderView(
+      doc([
+        para([
+          text("click", [
+            { type: "link", attrs: { href: "javascript:alert(1)" } },
+          ]),
+        ]),
+      ]),
+    );
+    const a = container.querySelector("a");
+    expect(a).not.toBeNull();
+    // No navigable javascript: href — attribute is absent (or empty).
+    expect(a?.getAttribute("href")).toBeFalsy();
+    // The link text is still rendered.
+    expect(a?.textContent).toBe("click");
+  });
+
+  it("neutralizes a control-char-obfuscated javascript: href", () => {
+    const { container } = renderView(
+      doc([
+        para([
+          text("x", [
+            { type: "link", attrs: { href: "java\tscript:alert(1)" } },
+          ]),
+        ]),
+      ]),
+    );
+    expect(container.querySelector("a")?.getAttribute("href")).toBeFalsy();
+  });
+
+  it("neutralizes a data: link href", () => {
+    const { container } = renderView(
+      doc([
+        para([
+          text("x", [
+            {
+              type: "link",
+              attrs: { href: "data:text/html,<script>alert(1)</script>" },
+            },
+          ]),
+        ]),
+      ]),
+    );
+    expect(container.querySelector("a")?.getAttribute("href")).toBeFalsy();
+  });
+
+  it("preserves a mailto: link href (allowlisted scheme)", () => {
+    const { container } = renderView(
+      doc([
+        para([
+          text("mail", [
+            { type: "link", attrs: { href: "mailto:a@b.com" } },
+          ]),
+        ]),
+      ]),
+    );
+    expect(container.querySelector("a")?.getAttribute("href")).toBe(
+      "mailto:a@b.com",
+    );
+  });
+
+  it("preserves a relative link href (no scheme, not a script vector)", () => {
+    const { container } = renderView(
+      doc([
+        para([
+          text("rel", [{ type: "link", attrs: { href: "/some/path" } }]),
+        ]),
+      ]),
+    );
+    expect(container.querySelector("a")?.getAttribute("href")).toBe(
+      "/some/path",
+    );
+  });
+
+  it("nests multiple marks on one text node", () => {
+    const { container } = renderView(
+      doc([para([text("x", [{ type: "bold" }, { type: "italic" }])])]),
+    );
+    // bold wraps italic (or vice versa) — both elements exist around the text.
+    expect(container.querySelector("strong")).not.toBeNull();
+    expect(container.querySelector("em")).not.toBeNull();
+    expect(screen.getByText("x")).toBeDefined();
+  });
+
+  it("renders hardBreak as <br/>", () => {
+    const { container } = renderView(
+      doc([para([text("a"), { type: "hardBreak" }, text("b")])]),
+    );
+    expect(container.querySelector("br")).not.toBeNull();
+  });
+
+  it("renders a user mention as a styled span", () => {
+    const { container } = renderView(
+      doc([
+        para([
+          {
+            type: "mention",
+            attrs: { label: "Alice", entityType: "user", entityId: "u1" },
+          },
+        ]),
+      ]),
+    );
+    expect(screen.getByText("@Alice")).toBeDefined();
+    // No fallback to the editor.
+    expect(screen.queryByTestId("comment-editor-fallback")).toBeNull();
+  });
+
+  it("renders a page mention as a link", () => {
+    const { container } = renderView(
+      doc([
+        para([
+          {
+            type: "mention",
+            attrs: {
+              label: "Some Page",
+              entityType: "page",
+              slugId: "pg1",
+            },
+          },
+        ]),
+      ]),
+    );
+    expect(container.querySelector("a")).not.toBeNull();
+    expect(screen.getByText("Some Page")).toBeDefined();
+  });
+
+  it("renders a legacy plain-text (non-JSON) string as plain text", () => {
+    renderView("just a legacy string");
+    expect(screen.getByText("just a legacy string")).toBeDefined();
+    expect(screen.queryByTestId("comment-editor-fallback")).toBeNull();
+  });
+
+  it("falls back to CommentEditor for an unknown node type", () => {
+    renderView(doc([{ type: "codeBlock", content: [text("x")] }]));
+    expect(screen.getByTestId("comment-editor-fallback")).toBeDefined();
+  });
+
+  it("falls back to CommentEditor for malformed JSON", () => {
+    renderView('{"type":"doc","content":[');
+    expect(screen.getByTestId("comment-editor-fallback")).toBeDefined();
+  });
+});

apps/client/src/features/comment/components/comment-content-view.tsx

@@ -0,0 +1,199 @@
+import React from "react";
+import classes from "./comment.module.css";
+import { MentionContent } from "@/features/editor/components/mention/mention-view";
+import CommentEditor from "@/features/comment/components/comment-editor";
+
+// Static, editor-free renderer of a comment body (ProseMirror JSON). It walks the
+// document and emits plain DOM, avoiding the cost of a full TipTap/ProseMirror
+// instance per comment (the panel used to spin up 400+ editors on mount).
+//
+// The supported node/mark set MUST mirror what CommentEditor enables
+// (StarterKit + Mention + LinkExtension). Anything outside that set makes the
+// whole comment degrade to the read-only CommentEditor via the fallback below,
+// so we never show a half-rendered comment.
+
+// Sentinel thrown when we hit a node/mark we don't know how to render statically.
+// Caught at the top level to trigger the CommentEditor fallback for the whole comment.
+class UnknownNodeError extends Error {}
+
+// Protocol allowlist mirroring @tiptap/extension-link's default (the read-only
+// CommentEditor path relies on it to blank javascript:/data: hrefs). The static
+// renderer must apply the SAME sanitization because the backend stores comment
+// content verbatim and React does not neutralize javascript: in an href.
+const ALLOWED_URI_SCHEMES = /^(?:https?|ftps?|mailto|tel|callto|sms|cid|xmpp):/i;
+
+function safeHref(href: unknown): string | undefined {
+  if (typeof href !== "string") return undefined;
+  // Strip control chars/whitespace that could smuggle a scheme past the test
+  // (e.g. "java\tscript:").
+  const cleaned = href.replace(/[\u0000-\u0020]/g, "").trim();
+  // Allow relative/anchor/protocol-relative links (no scheme) — not script vectors.
+  if (!/^[a-z][a-z0-9+.-]*:/i.test(cleaned)) return href;
+  return ALLOWED_URI_SCHEMES.test(cleaned) ? href : undefined;
+}
+
+interface PMMark {
+  type: string;
+  attrs?: Record<string, any>;
+}
+
+interface PMNode {
+  type: string;
+  attrs?: Record<string, any>;
+  content?: PMNode[];
+  text?: string;
+  marks?: PMMark[];
+}
+
+// Wrap a text node's string in its marks (marks nest, e.g. bold + italic).
+function renderMarks(
+  text: React.ReactNode,
+  marks: PMMark[] | undefined,
+  keyPrefix: string,
+): React.ReactNode {
+  if (!marks || marks.length === 0) return text;
+
+  return marks.reduce<React.ReactNode>((acc, mark, i) => {
+    const key = `${keyPrefix}-m${i}`;
+    switch (mark.type) {
+      case "bold":
+        return <strong key={key}>{acc}</strong>;
+      case "italic":
+        return <em key={key}>{acc}</em>;
+      case "strike":
+        return <s key={key}>{acc}</s>;
+      case "underline":
+        // StarterKit enables the Underline extension by default (Mod-u) and
+        // CommentEditor does not disable it, so real comments can carry this
+        // mark. Render it here rather than degrading the whole comment.
+        return <u key={key}>{acc}</u>;
+      case "code":
+        return <code key={key}>{acc}</code>;
+      case "link": {
+        // LinkExtension (TiptapLink) opens links in a new tab; keep the same
+        // safe rel semantics the editor produces. Sanitize the href against the
+        // extension's protocol allowlist — a disallowed scheme (javascript:,
+        // data:) yields undefined so the anchor is non-navigable but still shows
+        // its text, matching how extension-link blanks a bad href.
+        const href = safeHref(mark.attrs?.href);
+        return (
+          <a
+            key={key}
+            href={href}
+            target="_blank"
+            rel="noopener noreferrer nofollow"
+          >
+            {acc}
+          </a>
+        );
+      }
+      default:
+        throw new UnknownNodeError(`Unknown mark type: ${mark.type}`);
+    }
+  }, text);
+}
+
+function renderNode(node: PMNode, key: string): React.ReactNode {
+  switch (node.type) {
+    case "paragraph":
+      return <p key={key}>{renderChildren(node.content, key)}</p>;
+    case "text":
+      return (
+        <React.Fragment key={key}>
+          {renderMarks(node.text ?? "", node.marks, key)}
+        </React.Fragment>
+      );
+    case "hardBreak":
+      return <br key={key} />;
+    case "mention":
+      return (
+        <span key={key} style={{ display: "inline" }}>
+          <MentionContent attrs={node.attrs as any} />
+        </span>
+      );
+    default:
+      throw new UnknownNodeError(`Unknown node type: ${node.type}`);
+  }
+}
+
+function renderChildren(
+  content: PMNode[] | undefined,
+  keyPrefix: string,
+): React.ReactNode {
+  if (!content) return null;
+  return content.map((child, i) => renderNode(child, `${keyPrefix}-${i}`));
+}
+
+// Reproduce the exact DOM nesting the read-only CommentEditor renders so the
+// scoped CSS in comment.module.css (which targets
+// `.commentEditor .ProseMirror :global(.ProseMirror)` and `.ProseMirror p`)
+// applies pixel-for-pixel. Read-only => no data-editable / data-surface attrs.
+function Shell({ children }: { children: React.ReactNode }) {
+  return (
+    <div className={classes.commentEditor}>
+      <div className={classes.ProseMirror}>
+        <div className="ProseMirror">{children}</div>
+      </div>
+    </div>
+  );
+}
+
+interface CommentContentViewProps {
+  content: string | object;
+}
+
+export function CommentContentView({ content }: CommentContentViewProps) {
+  // Degrade this single comment to the old editor-based render (safety valve).
+  const fallback = () => {
+    if (import.meta.env.DEV) {
+      console.warn(
+        "CommentContentView: unsupported comment content, falling back to editor",
+      );
+    }
+    return <CommentEditor defaultContent={content} editable={false} />;
+  };
+
+  let doc: unknown = content;
+
+  if (typeof content === "string") {
+    try {
+      doc = JSON.parse(content);
+    } catch {
+      const trimmed = content.trim();
+      // Looks like it was meant to be JSON but is malformed -> safety-valve fallback.
+      if (trimmed.startsWith("{") || trimmed.startsWith("[")) {
+        return fallback();
+      }
+      // Otherwise it's a legacy plain-text comment: render as a single paragraph.
+      return (
+        <Shell>
+          <p>{content}</p>
+        </Shell>
+      );
+    }
+  }
+
+  // Double-stringified / legacy plain-text stored as a JSON string.
+  if (typeof doc === "string") {
+    return (
+      <Shell>
+        <p>{doc}</p>
+      </Shell>
+    );
+  }
+
+  try {
+    const pmDoc = doc as PMNode;
+    if (!pmDoc || typeof pmDoc !== "object" || pmDoc.type !== "doc") {
+      throw new UnknownNodeError("Not a ProseMirror doc");
+    }
+    return <Shell>{renderChildren(pmDoc.content, "n")}</Shell>;
+  } catch (err) {
+    if (err instanceof UnknownNodeError) {
+      return fallback();
+    }
+    throw err;
+  }
+}
+
+export default CommentContentView;

apps/client/src/features/comment/components/comment-list-item.test.tsx

@@ -1,5 +1,5 @@
-import { describe, it, expect, vi } from "vitest";
-import { render, screen, fireEvent } from "@testing-library/react";
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+import { render, screen, fireEvent, waitFor } from "@testing-library/react";
 import { MantineProvider } from "@mantine/core";
 import { IComment } from "@/features/comment/types/comment.types";
 
@@ -8,23 +8,74 @@ import { IComment } from "@/features/comment/types/comment.types";
 // The comment mutation hooks reach out to react-query/network — stub them so the
 // component renders in isolation. We only assert the AI-badge rendering branch.
 const applyMutateAsync = vi.fn();
+const dismissMutateAsync = vi.fn();
+const updateMutateAsync = vi.fn();
 vi.mock("@/features/comment/queries/comment-query", () => ({
   useDeleteCommentMutation: () => ({ mutateAsync: vi.fn() }),
   useResolveCommentMutation: () => ({ mutateAsync: vi.fn() }),
-  useUpdateCommentMutation: () => ({ mutateAsync: vi.fn() }),
+  useUpdateCommentMutation: () => ({ mutateAsync: updateMutateAsync }),
   useApplySuggestionMutation: () => ({
     mutateAsync: applyMutateAsync,
     isPending: false,
   }),
+  useDismissSuggestionMutation: () => ({
+    mutateAsync: dismissMutateAsync,
+    isPending: false,
+  }),
 }));
 
+// The document the mocked editor emits via onUpdate when the edit form is open.
+// Duplicated inside the mock factory (below) to keep the factory self-contained.
+const EDITED_DOC = {
+  type: "doc",
+  content: [
+    { type: "paragraph", content: [{ type: "text", text: "edited via editor" }] },
+  ],
+};
+
 // CommentEditor pulls in the full TipTap editor stack; replace it with a stub.
-vi.mock("@/features/comment/components/comment-editor", () => ({
-  default: () => <div data-testid="comment-editor" />,
+// In edit mode the stub exposes buttons that fire the real onUpdate/onSave props
+// so the edit->save/cancel flow can be driven without a live editor.
+vi.mock("@/features/comment/components/comment-editor", () => {
+  const doc = {
+    type: "doc",
+    content: [
+      { type: "paragraph", content: [{ type: "text", text: "edited via editor" }] },
+    ],
+  };
+  return {
+    default: ({ onUpdate, onSave }: any) => (
+      <div data-testid="comment-editor">
+        <button
+          type="button"
+          data-testid="editor-emit-update"
+          onClick={() => onUpdate?.(doc)}
+        />
+        <button
+          type="button"
+          data-testid="editor-emit-save"
+          onClick={() => onSave?.()}
+        />
+      </div>
+    ),
+  };
+});
+
+// CommentContentView (used for the read-only body) imports the mention view,
+// which pulls page-query -> main.tsx (createRoot). Stub the queries so the item
+// renders in isolation without the app entry side-effect.
+vi.mock("@/features/page/queries/page-query.ts", () => ({
+  usePageQuery: () => ({ data: undefined, isLoading: false, isError: false }),
+}));
+vi.mock("@/features/share/queries/share-query.ts", () => ({
+  useSharePageQuery: () => ({ data: undefined }),
 }));
 
 import CommentListItem from "./comment-list-item";
-import { canShowApply } from "@/features/comment/utils/suggestion";
+import {
+  canShowApply,
+  canShowDismiss,
+} from "@/features/comment/utils/suggestion";
 
 const baseComment = (over?: Partial<IComment>): IComment =>
   ({
@@ -38,14 +89,20 @@ const baseComment = (over?: Partial<IComment>): IComment =>
     ...over,
   }) as IComment;
 
-function renderItem(comment: IComment, canEdit = true) {
+function renderItem(
+  comment: IComment,
+  canEdit = true,
+  canComment = true,
+  userSpaceRole?: string,
+) {
   return render(
     <MantineProvider>
       <CommentListItem
         comment={comment}
         pageId="page-1"
-        canComment={true}
+        canComment={canComment}
         canEdit={canEdit}
+        userSpaceRole={userSpaceRole}
       />
     </MantineProvider>,
   );
@@ -159,6 +216,65 @@ describe("CommentListItem — suggested edit (#315)", () => {
   });
 });
 
+describe("CommentListItem — dismiss suggestion (#329)", () => {
+  const suggestion = (over?: Partial<IComment>): IComment =>
+    baseComment({
+      selection: "old wording here",
+      suggestedText: "new wording here",
+      ...over,
+    });
+
+  // A space admin (userSpaceRole="admin") satisfies the owner-or-admin gate
+  // regardless of who authored the comment; the tests below use it as the lever
+  // since the currentUser atom is unseeded (null) in this harness.
+  it("renders a Dismiss button alongside Apply when canEdit and canComment (owner/admin)", () => {
+    renderItem(suggestion(), true, true, "admin");
+    expect(screen.getByRole("button", { name: "Apply" })).toBeDefined();
+    expect(screen.getByRole("button", { name: "Dismiss" })).toBeDefined();
+  });
+
+  it("shows Dismiss but NOT Apply for an admin commenter who cannot edit", () => {
+    renderItem(suggestion(), false, true, "admin");
+    expect(screen.queryByRole("button", { name: "Apply" })).toBeNull();
+    expect(screen.getByRole("button", { name: "Dismiss" })).toBeDefined();
+  });
+
+  it("hides Dismiss when the viewer cannot comment", () => {
+    renderItem(suggestion(), false, false, "admin");
+    expect(screen.queryByRole("button", { name: "Dismiss" })).toBeNull();
+    expect(screen.queryByRole("button", { name: "Apply" })).toBeNull();
+  });
+
+  it("hides Dismiss for a non-owner non-admin even with canComment (#338 F5: mirrors server 403)", () => {
+    // canComment=true but NOT a space admin and NOT the comment owner (the
+    // currentUser atom is null while the comment is authored by user-1), so the
+    // server would 403 a dismiss — the button must not be shown at all.
+    renderItem(suggestion(), false, true, "member");
+    expect(screen.queryByRole("button", { name: "Dismiss" })).toBeNull();
+  });
+
+  it("hides Dismiss once the thread is resolved", () => {
+    renderItem(suggestion({ resolvedAt: new Date() }), true, true, "admin");
+    expect(screen.queryByRole("button", { name: "Dismiss" })).toBeNull();
+  });
+
+  it("hides Dismiss (shows the Applied badge) once applied", () => {
+    renderItem(suggestion({ suggestionAppliedAt: new Date() }), true, true, "admin");
+    expect(screen.queryByRole("button", { name: "Dismiss" })).toBeNull();
+    expect(screen.getByText("Applied")).toBeDefined();
+  });
+
+  it("calls the dismiss mutation when the Dismiss button is clicked", () => {
+    dismissMutateAsync.mockClear();
+    renderItem(suggestion(), true, true, "admin");
+    fireEvent.click(screen.getByRole("button", { name: "Dismiss" }));
+    expect(dismissMutateAsync).toHaveBeenCalledWith({
+      commentId: "c-1",
+      pageId: "page-1",
+    });
+  });
+});
+
 describe("canShowApply predicate", () => {
   const c = (over?: Partial<IComment>): IComment =>
     ({ suggestedText: "x", ...over }) as IComment;
@@ -184,3 +300,161 @@ describe("canShowApply predicate", () => {
     expect(canShowApply(c({ parentCommentId: "p" }), true)).toBe(false);
   });
 });
+
+describe("canShowDismiss predicate", () => {
+  const c = (over?: Partial<IComment>): IComment =>
+    ({ suggestedText: "x", ...over }) as IComment;
+
+  it("true when suggestion present, can comment, owner/admin, not applied/resolved, top-level", () => {
+    expect(canShowDismiss(c(), true, true)).toBe(true);
+  });
+  it("false without comment permission", () => {
+    expect(canShowDismiss(c(), false, true)).toBe(false);
+  });
+  it("false when not owner and not admin (#338 F5)", () => {
+    expect(canShowDismiss(c(), true, false)).toBe(false);
+  });
+  it("false when no suggestion", () => {
+    expect(canShowDismiss(c({ suggestedText: null }), true, true)).toBe(false);
+  });
+  it("false when already applied", () => {
+    expect(canShowDismiss(c({ suggestionAppliedAt: new Date() }), true, true)).toBe(
+      false,
+    );
+  });
+  it("false when resolved", () => {
+    expect(canShowDismiss(c({ resolvedAt: new Date() }), true, true)).toBe(false);
+  });
+  it("false for a reply comment", () => {
+    expect(canShowDismiss(c({ parentCommentId: "p" }), true, true)).toBe(false);
+  });
+});
+
+describe("CommentListItem — edit -> save/cancel flow (#340 F3)", () => {
+  const body = (t: string) =>
+    JSON.stringify({
+      type: "doc",
+      content: [{ type: "paragraph", content: [{ type: "text", text: t }] }],
+    });
+
+  // The edit menu item is gated on the viewer owning the comment
+  // (currentUser.id === creatorId). currentUserAtom is atomWithStorage-backed,
+  // so seed localStorage to make the viewer the owner (creatorId "user-1").
+  beforeEach(() => {
+    updateMutateAsync.mockClear();
+    localStorage.setItem(
+      "currentUser",
+      JSON.stringify({ user: { id: "user-1", name: "Owner" } }),
+    );
+  });
+  afterEach(() => {
+    localStorage.clear();
+  });
+
+  async function openEditor() {
+    // Open the comment menu, then click "Edit comment" to toggle into edit mode.
+    fireEvent.click(screen.getByLabelText("Comment menu"));
+    fireEvent.click(await screen.findByText("Edit comment"));
+    // Edit form (mocked editor + actions) is now mounted.
+    await screen.findByTestId("comment-editor");
+  }
+
+  it("saves the edited content and, on cache update, shows the new body", async () => {
+    const { rerender } = renderItem(
+      baseComment({ content: body("original body") }),
+    );
+    // Static body first.
+    expect(screen.getByText("original body")).toBeDefined();
+
+    await openEditor();
+
+    // Editor emits an update (populates editContentRef), then Save is clicked.
+    fireEvent.click(screen.getByTestId("editor-emit-update"));
+    fireEvent.click(screen.getByRole("button", { name: "Save" }));
+
+    // mutateAsync is called with the stringified edited doc.
+    expect(updateMutateAsync).toHaveBeenCalledWith({
+      commentId: "c-1",
+      content: JSON.stringify(EDITED_DOC),
+    });
+
+    // On success the form closes (isEditing -> false); the static body renders
+    // from the comment.content prop again.
+    await waitFor(() =>
+      expect(screen.queryByTestId("comment-editor")).toBeNull(),
+    );
+
+    // Simulate the cache invalidation swapping in a new comment object with the
+    // updated content — the static body reflects it.
+    rerender(
+      <MantineProvider>
+        <CommentListItem
+          comment={baseComment({ content: body("updated body after save") })}
+          pageId="page-1"
+          canComment={true}
+          canEdit={true}
+        />
+      </MantineProvider>,
+    );
+    expect(screen.getByText("updated body after save")).toBeDefined();
+    expect(screen.queryByText("original body")).toBeNull();
+  });
+
+  it("cancel restores the static body and does not call the update mutation", async () => {
+    renderItem(baseComment({ content: body("original body") }));
+    await openEditor();
+
+    // Type something (editContentRef set), then cancel.
+    fireEvent.click(screen.getByTestId("editor-emit-update"));
+    fireEvent.click(screen.getByRole("button", { name: "Cancel" }));
+
+    // Editor unmounts, static body restored, no save happened.
+    await waitFor(() =>
+      expect(screen.queryByTestId("comment-editor")).toBeNull(),
+    );
+    expect(screen.getByText("original body")).toBeDefined();
+    expect(updateMutateAsync).not.toHaveBeenCalled();
+  });
+
+  it("saving without editing sends the existing content (editContentRef cleared after cancel)", async () => {
+    renderItem(baseComment({ content: body("original body") }));
+
+    // Cancel path clears editContentRef...
+    await openEditor();
+    fireEvent.click(screen.getByTestId("editor-emit-update"));
+    fireEvent.click(screen.getByRole("button", { name: "Cancel" }));
+    await waitFor(() =>
+      expect(screen.queryByTestId("comment-editor")).toBeNull(),
+    );
+
+    // ...so re-opening and saving WITHOUT an update falls back to comment.content.
+    await openEditor();
+    fireEvent.click(screen.getByRole("button", { name: "Save" }));
+    expect(updateMutateAsync).toHaveBeenCalledWith({
+      commentId: "c-1",
+      content: JSON.stringify(body("original body")),
+    });
+  });
+});
+
+describe("CommentListItem — read-only body renders statically", () => {
+  it("renders the comment body as static text without a TipTap editor", () => {
+    renderItem(
+      baseComment({
+        content: JSON.stringify({
+          type: "doc",
+          content: [
+            {
+              type: "paragraph",
+              content: [{ type: "text", text: "Hello static world" }],
+            },
+          ],
+        }),
+      }),
+    );
+    // Body text is present...
+    expect(screen.getByText("Hello static world")).toBeDefined();
+    // ...and it did NOT go through the (mocked) CommentEditor instance.
+    expect(screen.queryByTestId("comment-editor")).toBeNull();
+  });
+});

apps/client/src/features/comment/components/comment-list-item.tsx

@@ -1,10 +1,11 @@
 import { Group, Text, Box, Badge, Button } from "@mantine/core";
 import { AgentAvatarStack } from "@/components/ui/agent-avatar-stack.tsx";
-import React, { useEffect, useMemo, useRef, useState } from "react";
+import React, { useMemo, useRef, useState } from "react";
 import classes from "./comment.module.css";
 import { useAtom, useAtomValue } from "jotai";
 import { useTimeAgo } from "@/hooks/use-time-ago";
 import CommentEditor from "@/features/comment/components/comment-editor";
+import CommentContentView from "@/features/comment/components/comment-content-view";
 import { pageEditorAtom } from "@/features/editor/atoms/editor-atoms";
 import CommentActions from "@/features/comment/components/comment-actions";
 import CommentMenu from "@/features/comment/components/comment-menu";
@@ -13,12 +14,14 @@ import { useHover } from "@mantine/hooks";
 import {
   useApplySuggestionMutation,
   useDeleteCommentMutation,
+  useDismissSuggestionMutation,
   useResolveCommentMutation,
   useUpdateCommentMutation,
 } from "@/features/comment/queries/comment-query";
 import { IComment } from "@/features/comment/types/comment.types";
 import {
   canShowApply,
+  canShowDismiss,
   computeSuggestionDiff,
 } from "@/features/comment/utils/suggestion";
 import { CustomAvatar } from "@/components/ui/custom-avatar.tsx";
@@ -48,12 +51,12 @@ function CommentListItem({
   const [isEditing, setIsEditing] = useState(false);
   const [isLoading, setIsLoading] = useState(false);
   const editor = useAtomValue(pageEditorAtom);
-  const [content, setContent] = useState<string>(comment.content);
   const editContentRef = useRef<any>(null);
   const updateCommentMutation = useUpdateCommentMutation();
   const deleteCommentMutation = useDeleteCommentMutation(comment.pageId);
   const resolveCommentMutation = useResolveCommentMutation();
   const applySuggestionMutation = useApplySuggestionMutation();
+  const dismissSuggestionMutation = useDismissSuggestionMutation();
   const [currentUser] = useAtom(currentUserAtom);
   const createdAtAgo = useTimeAgo(comment.createdAt);
 
@@ -69,22 +72,22 @@ function CommentListItem({
     [comment.selection, comment.suggestedText],
   );
 
-  useEffect(() => {
-    setContent(comment.content);
-  }, [comment]);
+  // Owner-or-space-admin gate (#338): mirrors the server authz for both the
+  // comment menu (edit/delete) and the suggestion Dismiss button, so we never
+  // render an action the server will 403.
+  const isOwnerOrAdmin =
+    currentUser?.user?.id === comment.creatorId || userSpaceRole === "admin";
+
 
   async function handleUpdateComment() {
     try {
       setIsLoading(true);
       const commentToUpdate = {
         commentId: comment.id,
-        content: JSON.stringify(editContentRef.current ?? content),
+        content: JSON.stringify(editContentRef.current ?? comment.content),
       };
       await updateCommentMutation.mutateAsync(commentToUpdate);
-      if (editContentRef.current) {
-        setContent(editContentRef.current);
-        editContentRef.current = null;
-      }
+      editContentRef.current = null;
       setIsEditing(false);
     } catch (error) {
       console.error("Failed to update comment:", error);
@@ -130,6 +133,19 @@ function CommentListItem({
     }
   }
 
+  async function handleDismissSuggestion() {
+    try {
+      await dismissSuggestionMutation.mutateAsync({
+        commentId: comment.id,
+        pageId: comment.pageId,
+      });
+    } catch (error) {
+      // Idempotent races are reconciled to success in the mutation's onError;
+      // anything else surfaces there as a notification.
+      console.error("Failed to dismiss suggestion:", error);
+    }
+  }
+
   function handleCommentClick(comment: IComment) {
     const el = document.querySelector(
       `.comment-mark[data-comment-id="${comment.id}"]`,
@@ -205,7 +221,7 @@ function CommentListItem({
                 />
               )}
 
-              {(currentUser?.user?.id === comment.creatorId || userSpaceRole === 'admin') && (
+              {isOwnerOrAdmin && (
                 <CommentMenu
                   onEditComment={handleEditToggle}
                   onDeleteComment={handleDeleteComment}
@@ -286,29 +302,53 @@ function CommentListItem({
                 {t("Applied")}
               </Badge>
             ) : (
-              canShowApply(comment, canEdit) && (
-                <Button
-                  size="compact-xs"
-                  variant="light"
-                  color="green"
-                  mt={6}
-                  onClick={handleApplySuggestion}
-                  loading={applySuggestionMutation.isPending}
-                  disabled={applySuggestionMutation.isPending}
-                >
-                  {t("Apply")}
-                </Button>
+              (canShowApply(comment, canEdit) ||
+                canShowDismiss(comment, canComment, isOwnerOrAdmin)) && (
+                <Group gap="xs" mt={6}>
+                  {canShowApply(comment, canEdit) && (
+                    <Button
+                      size="compact-xs"
+                      variant="light"
+                      color="green"
+                      onClick={handleApplySuggestion}
+                      loading={applySuggestionMutation.isPending}
+                      disabled={
+                        applySuggestionMutation.isPending ||
+                        dismissSuggestionMutation.isPending
+                      }
+                    >
+                      {t("Apply")}
+                    </Button>
+                  )}
+                  {/* Dismiss ("Не применять", #329): removes the suggestion
+                      without changing the page text. Gated on canComment. */}
+                  {canShowDismiss(comment, canComment, isOwnerOrAdmin) && (
+                    <Button
+                      size="compact-xs"
+                      variant="subtle"
+                      color="gray"
+                      onClick={handleDismissSuggestion}
+                      loading={dismissSuggestionMutation.isPending}
+                      disabled={
+                        applySuggestionMutation.isPending ||
+                        dismissSuggestionMutation.isPending
+                      }
+                    >
+                      {t("Dismiss")}
+                    </Button>
+                  )}
+                </Group>
               )
             )}
           </Box>
         )}
 
         {!isEditing ? (
-          <CommentEditor defaultContent={content} editable={false} />
+          <CommentContentView content={comment.content} />
         ) : (
           <>
             <CommentEditor
-              defaultContent={content}
+              defaultContent={comment.content}
               editable={true}
               onUpdate={(newContent: any) => { editContentRef.current = newContent; }}
               onSave={handleUpdateComment}
@@ -328,4 +368,6 @@ function CommentListItem({
   );
 }
 
-export default CommentListItem;
+// Memoized so a resolve/apply/reply cache update (which only replaces the touched
+// comment's object identity) re-renders that one thread, not all ~356 items.
+export default React.memo(CommentListItem);

apps/client/src/features/comment/components/comment-list-with-tabs.test.tsx

@@ -0,0 +1,108 @@
+import { describe, it, expect, vi } from "vitest";
+import { render, screen, fireEvent } from "@testing-library/react";
+import { MantineProvider } from "@mantine/core";
+import { IComment } from "@/features/comment/types/comment.types";
+
+// matchMedia (read by MantineProvider) is stubbed globally in vitest.setup.ts.
+
+// CommentEditor pulls in the full TipTap editor stack; replace it with a stub so
+// the lazy reply editor's mount transition can be observed without the editor.
+vi.mock("@/features/comment/components/comment-editor", () => ({
+  default: () => <div data-testid="comment-editor" />,
+}));
+
+// page-query -> main.tsx (createRoot) is a module side effect; stub the queries
+// pulled in transitively so importing the module is side-effect free.
+vi.mock("@/features/page/queries/page-query.ts", () => ({
+  usePageQuery: () => ({ data: undefined, isLoading: false, isError: false }),
+}));
+vi.mock("@/features/share/queries/share-query.ts", () => ({
+  useSharePageQuery: () => ({ data: undefined }),
+}));
+// space-query -> main.tsx (createRoot) is another module side effect; stub it.
+vi.mock("@/features/space/queries/space-query.ts", () => ({
+  useGetSpaceBySlugQuery: () => ({ data: undefined }),
+}));
+
+import {
+  buildChildrenByParent,
+  CommentEditorWithActions,
+} from "./comment-list-with-tabs";
+
+const c = (id: string, parentCommentId: string | null = null): IComment =>
+  ({ id, parentCommentId }) as IComment;
+
+describe("buildChildrenByParent (childrenByParent grouping)", () => {
+  it("returns an empty map for undefined or empty input", () => {
+    expect(buildChildrenByParent(undefined).size).toBe(0);
+    expect(buildChildrenByParent([]).size).toBe(0);
+  });
+
+  it("does not index a top-level comment (parentCommentId null)", () => {
+    const map = buildChildrenByParent([c("p1", null)]);
+    expect(map.size).toBe(0);
+    expect(map.has("p1")).toBe(false);
+  });
+
+  it("groups replies under the correct parent, including reply-to-reply nesting", () => {
+    const p1 = c("p1", null);
+    const r1 = c("r1", "p1");
+    const r2 = c("r2", "r1"); // a reply to a reply
+    const map = buildChildrenByParent([p1, r1, r2]);
+    expect(map.get("p1")).toEqual([r1]);
+    expect(map.get("r1")).toEqual([r2]);
+    // The top-level comment itself is never a key.
+    expect(map.has("p1") && map.get("p1")?.length).toBe(1);
+  });
+
+  it("still groups a reply whose parent is not present in items", () => {
+    const orphan = c("o1", "missing-parent");
+    const map = buildChildrenByParent([orphan]);
+    expect(map.get("missing-parent")).toEqual([orphan]);
+  });
+
+  it("preserves insertion order among sibling replies", () => {
+    const map = buildChildrenByParent([
+      c("a", "p1"),
+      c("b", "p1"),
+      c("d", "p1"),
+    ]);
+    expect(map.get("p1")?.map((x) => x.id)).toEqual(["a", "b", "d"]);
+  });
+});
+
+function renderReplyEditor() {
+  return render(
+    <MantineProvider>
+      <CommentEditorWithActions commentId="c-1" onSave={vi.fn()} />
+    </MantineProvider>,
+  );
+}
+
+describe("CommentEditorWithActions — lazy reply editor activation", () => {
+  it("shows only the stub initially (no editor instance mounted)", () => {
+    renderReplyEditor();
+    expect(screen.getByRole("button")).toBeDefined();
+    expect(screen.queryByTestId("comment-editor")).toBeNull();
+  });
+
+  it("mounts the real editor when the stub is clicked and keeps it mounted", () => {
+    renderReplyEditor();
+    fireEvent.click(screen.getByRole("button"));
+    expect(screen.getByTestId("comment-editor")).toBeDefined();
+    // The stub button is replaced by the editor subtree.
+    expect(screen.queryByRole("button")).toBeNull();
+  });
+
+  it("mounts the editor when the stub receives focus", () => {
+    renderReplyEditor();
+    fireEvent.focus(screen.getByRole("button"));
+    expect(screen.getByTestId("comment-editor")).toBeDefined();
+  });
+
+  it("mounts the editor on Enter keydown of the stub", () => {
+    renderReplyEditor();
+    fireEvent.keyDown(screen.getByRole("button"), { key: "Enter" });
+    expect(screen.getByTestId("comment-editor")).toBeDefined();
+  });
+});

apps/client/src/features/comment/components/comment-list-with-tabs.tsx

@@ -23,7 +23,6 @@ import CommentActions from "@/features/comment/components/comment-actions";
 import { useFocusWithin } from "@mantine/hooks";
 import { IComment } from "@/features/comment/types/comment.types.ts";
 import { usePageQuery } from "@/features/page/queries/page-query.ts";
-import { IPagination } from "@/lib/types.ts";
 import { extractPageSlugId } from "@/lib";
 import { useTranslation } from "react-i18next";
 import { useGetSpaceBySlugQuery } from "@/features/space/queries/space-query.ts";
@@ -36,6 +35,24 @@ interface CommentListWithTabsProps {
   onClose?: () => void;
 }
 
+// Index replies by their parent id once (O(n)), instead of an O(n^2) filter per
+// thread. Replies whose parent is not in `items` are still grouped under their
+// parentCommentId (they simply won't be reached by the top-level walk).
+// Exported for unit testing.
+export function buildChildrenByParent(
+  items: IComment[] | undefined,
+): Map<string, IComment[]> {
+  const m = new Map<string, IComment[]>();
+  for (const c of items ?? []) {
+    if (c.parentCommentId) {
+      const arr = m.get(c.parentCommentId);
+      if (arr) arr.push(c);
+      else m.set(c.parentCommentId, [c]);
+    }
+  }
+  return m;
+}
+
 function CommentListWithTabs({ onClose }: CommentListWithTabsProps) {
   const { t } = useTranslation();
   const { pageSlug } = useParams();
@@ -46,7 +63,9 @@ function CommentListWithTabs({ onClose }: CommentListWithTabsProps) {
     isError,
   } = useCommentsQuery({ pageId: page?.id });
   const createCommentMutation = useCreateCommentMutation();
-  const [isLoading, setIsLoading] = useState(false);
+  // mutateAsync is a stable reference across renders; depend on it (not the
+  // mutation object) so the reply/comment callbacks stay stable.
+  const createCommentAsync = createCommentMutation.mutateAsync;
   const { data: space } = useGetSpaceBySlugQuery(page?.space?.slug);
 
   const canEdit = page?.permissions?.canEdit ?? false;
@@ -75,13 +94,21 @@ function CommentListWithTabs({ onClose }: CommentListWithTabsProps) {
     return { activeComments: active, resolvedComments: resolved };
   }, [comments]);
 
+  // Index replies by their parent once, instead of an O(n^2) filter per thread.
+  // The map ref changes on any comments update, so MemoizedChildComments re-runs
+  // (cheap) and re-looks-up, while memoized CommentListItems skip unchanged items.
+  const childrenByParent = useMemo(
+    () => buildChildrenByParent(comments?.items),
+    [comments?.items],
+  );
+
   const [isPageCommentLoading, setIsPageCommentLoading] = useState(false);
 
   const handleAddPageComment = useCallback(
     async (_commentId: string, content: string) => {
       try {
         setIsPageCommentLoading(true);
-        const createdComment = await createCommentMutation.mutateAsync({
+        const createdComment = await createCommentAsync({
           pageId: page?.id,
           content: JSON.stringify(content),
         });
@@ -100,27 +127,26 @@ function CommentListWithTabs({ onClose }: CommentListWithTabsProps) {
         setIsPageCommentLoading(false);
       }
     },
-    [createCommentMutation, page?.id],
+    [createCommentAsync, page?.id],
   );
 
   const handleAddReply = useCallback(
     async (commentId: string, content: string) => {
+      // Pending state lives inside CommentEditorWithActions so sending a reply
+      // does not churn renderComments and re-render the whole list.
       try {
-        setIsLoading(true);
         const commentData = {
           pageId: page?.id,
           parentCommentId: commentId,
           content: JSON.stringify(content),
         };
 
-        await createCommentMutation.mutateAsync(commentData);
+        await createCommentAsync(commentData);
       } catch (error) {
         console.error("Failed to post comment:", error);
-      } finally {
-        setIsLoading(false);
       }
     },
-    [createCommentMutation, page?.id],
+    [createCommentAsync, page?.id],
   );
 
   const renderComments = useCallback(
@@ -143,7 +169,7 @@ function CommentListWithTabs({ onClose }: CommentListWithTabsProps) {
             userSpaceRole={space?.membership?.role}
           />
           <MemoizedChildComments
-            comments={comments}
+            childrenByParent={childrenByParent}
             parentId={comment.id}
             pageId={page?.id}
             canComment={canComment}
@@ -158,16 +184,15 @@ function CommentListWithTabs({ onClose }: CommentListWithTabsProps) {
             <CommentEditorWithActions
               commentId={comment.id}
               onSave={handleAddReply}
-              isLoading={isLoading}
             />
           </>
         )}
       </Paper>
     ),
     [
-      comments,
+      childrenByParent,
       handleAddReply,
-      isLoading,
+      page?.id,
       space?.membership?.role,
       canComment,
       canEdit,
@@ -203,6 +228,11 @@ function CommentListWithTabs({ onClose }: CommentListWithTabsProps) {
       <Tabs
         defaultValue="open"
         variant="default"
+        // Default to not mounting an inactive tab (the heavy Resolved list stays
+        // unmounted while Open is shown). The Open panel overrides this with its
+        // own keepMounted (below) so an in-progress reply/edit draft survives an
+        // Open -> Resolved -> Open switch.
+        keepMounted={false}
         style={{
           flex: "1 1 auto",
           display: "flex",
@@ -261,7 +291,10 @@ function CommentListWithTabs({ onClose }: CommentListWithTabsProps) {
           type="scroll"
         >
           <div style={{ paddingBottom: "8px" }}>
-            <Tabs.Panel value="open" pt="xs">
+            {/* keepMounted keeps the Open panel alive even while Resolved is
+                active, so a lazily-mounted reply editor's draft (and an
+                in-progress edit) is not discarded on tab switch. */}
+            <Tabs.Panel value="open" pt="xs" keepMounted>
               {activeComments.length === 0 ? (
                 <Center py="xl">
                   <Stack align="center" gap="xs">
@@ -307,7 +340,7 @@ function CommentListWithTabs({ onClose }: CommentListWithTabsProps) {
 }
 
 interface ChildCommentsProps {
-  comments: IPagination<IComment>;
+  childrenByParent: Map<string, IComment[]>;
   parentId: string;
   pageId: string;
   canComment: boolean;
@@ -315,24 +348,18 @@ interface ChildCommentsProps {
   userSpaceRole?: string;
 }
 const ChildComments = ({
-  comments,
+  childrenByParent,
   parentId,
   pageId,
   canComment,
   canEdit,
   userSpaceRole,
 }: ChildCommentsProps) => {
-  const getChildComments = useCallback(
-    (parentId: string) =>
-      comments.items.filter(
-        (comment: IComment) => comment.parentCommentId === parentId,
-      ),
-    [comments.items],
-  );
+  const children = childrenByParent.get(parentId) ?? [];
 
   return (
     <div>
-      {getChildComments(parentId).map((childComment) => (
+      {children.map((childComment) => (
         <div key={childComment.id}>
           <CommentListItem
             comment={childComment}
@@ -342,7 +369,7 @@ const ChildComments = ({
             userSpaceRole={userSpaceRole}
           />
           <MemoizedChildComments
-            comments={comments}
+            childrenByParent={childrenByParent}
             parentId={childComment.id}
             pageId={pageId}
             canComment={canComment}
@@ -357,22 +384,61 @@ const ChildComments = ({
 
 const MemoizedChildComments = memo(ChildComments);
 
-const CommentEditorWithActions = ({
+export const CommentEditorWithActions = ({
   commentId,
   onSave,
-  isLoading,
   placeholder = undefined,
 }) => {
+  const { t } = useTranslation();
+  // Lazily mount the TipTap reply editor: until the user interacts with the
+  // stub, no editor instance is created for this thread. Once mounted it stays
+  // mounted so the draft is preserved.
+  const [mounted, setMounted] = useState(false);
   const [content, setContent] = useState("");
+  const [isSending, setIsSending] = useState(false);
   const { ref, focused } = useFocusWithin();
   const commentEditorRef = useRef(null);
 
-  const handleSave = useCallback(() => {
-    onSave(commentId, content);
-    setContent("");
-    commentEditorRef.current?.clearContent();
+  const activate = useCallback(() => setMounted(true), []);
+
+  const handleSave = useCallback(async () => {
+    try {
+      setIsSending(true);
+      await onSave(commentId, content);
+      setContent("");
+      commentEditorRef.current?.clearContent();
+    } finally {
+      setIsSending(false);
+    }
   }, [commentId, content, onSave]);
 
+  if (!mounted) {
+    return (
+      <div
+        role="button"
+        tabIndex={0}
+        onClick={activate}
+        onFocus={activate}
+        onKeyDown={(e) => {
+          if (e.key === "Enter" || e.key === " ") {
+            e.preventDefault();
+            activate();
+          }
+        }}
+        style={{
+          padding: "6px",
+          fontSize: "var(--mantine-font-size-sm)",
+          lineHeight: 1.4,
+          color: "var(--mantine-color-placeholder)",
+          cursor: "text",
+          borderRadius: "var(--mantine-radius-sm)",
+        }}
+      >
+        {placeholder || t("Reply...")}
+      </div>
+    );
+  }
+
   return (
     <div ref={ref}>
       <CommentEditor
@@ -381,8 +447,9 @@ const CommentEditorWithActions = ({
         onSave={handleSave}
         editable={true}
         placeholder={placeholder}
+        autofocus={true}
       />
-      {focused && <CommentActions onSave={handleSave} isLoading={isLoading} />}
+      {focused && <CommentActions onSave={handleSave} isLoading={isSending} />}
     </div>
   );
 };

apps/client/src/features/comment/queries/comment-query.suggestion-outcome.test.tsx

@@ -0,0 +1,279 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import React from "react";
+import { renderHook, waitFor } from "@testing-library/react";
+import {
+  QueryClient,
+  QueryClientProvider,
+  InfiniteData,
+} from "@tanstack/react-query";
+
+/**
+ * Coverage for the ephemeral-suggestion (#329) cache reconciliation in
+ * useApplySuggestionMutation / useDismissSuggestionMutation: the mutations act on
+ * the server `outcome` — 'deleted' drops the comment from the local list,
+ * 'resolved' relocates it (by stamping resolvedAt, which the tabs split on).
+ */
+
+vi.mock("@mantine/notifications", () => ({
+  notifications: { show: vi.fn() },
+}));
+
+vi.mock("@/features/comment/services/comment-service", () => ({
+  applySuggestion: vi.fn(),
+  dismissSuggestion: vi.fn(),
+  createComment: vi.fn(),
+  updateComment: vi.fn(),
+  deleteComment: vi.fn(),
+  resolveComment: vi.fn(),
+  getPageComments: vi.fn(),
+}));
+
+import { notifications } from "@mantine/notifications";
+import {
+  applySuggestion,
+  dismissSuggestion,
+} from "@/features/comment/services/comment-service";
+import {
+  useApplySuggestionMutation,
+  useDismissSuggestionMutation,
+  RQ_KEY,
+} from "@/features/comment/queries/comment-query";
+import { IComment } from "@/features/comment/types/comment.types";
+
+const PAGE_ID = "page-1";
+
+function seededClient(comment: IComment) {
+  const queryClient = new QueryClient({
+    defaultOptions: { mutations: { retry: false } },
+  });
+  const seed: InfiniteData<any> = {
+    pageParams: [undefined],
+    pages: [{ items: [comment], meta: { hasNextPage: false, nextCursor: null } }],
+  };
+  queryClient.setQueryData(RQ_KEY(PAGE_ID), seed);
+  const wrapper = ({ children }: { children: React.ReactNode }) => (
+    <QueryClientProvider client={queryClient}>{children}</QueryClientProvider>
+  );
+  return { queryClient, wrapper };
+}
+
+function items(queryClient: QueryClient): IComment[] {
+  const cache = queryClient.getQueryData(RQ_KEY(PAGE_ID)) as
+    | InfiniteData<any>
+    | undefined;
+  return cache?.pages.flatMap((p) => p.items) ?? [];
+}
+
+const comment = (over?: Partial<IComment>): IComment =>
+  ({
+    id: "c-1",
+    pageId: PAGE_ID,
+    content: "{}",
+    creatorId: "u-1",
+    workspaceId: "ws-1",
+    createdAt: new Date(),
+    suggestedText: "new",
+    ...over,
+  }) as IComment;
+
+describe("useApplySuggestionMutation — outcome handling (#329)", () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it("outcome=deleted → removes the comment from the list", async () => {
+    vi.mocked(applySuggestion).mockResolvedValue({
+      id: "c-1",
+      pageId: PAGE_ID,
+      outcome: "deleted",
+    } as any);
+    const { queryClient, wrapper } = seededClient(comment());
+
+    const { result } = renderHook(() => useApplySuggestionMutation(), {
+      wrapper,
+    });
+    await result.current.mutateAsync({ commentId: "c-1", pageId: PAGE_ID });
+    await waitFor(() => expect(result.current.isSuccess).toBe(true));
+
+    expect(items(queryClient)).toHaveLength(0);
+  });
+
+  it("outcome=resolved → keeps the comment and stamps resolvedAt/applied fields", async () => {
+    const resolvedAt = new Date();
+    vi.mocked(applySuggestion).mockResolvedValue({
+      id: "c-1",
+      pageId: PAGE_ID,
+      outcome: "resolved",
+      resolvedAt,
+      resolvedById: "u-1",
+      resolvedBy: { id: "u-1", name: "A" },
+      suggestionAppliedAt: resolvedAt,
+      suggestionAppliedById: "u-1",
+    } as any);
+    const { queryClient, wrapper } = seededClient(comment());
+
+    const { result } = renderHook(() => useApplySuggestionMutation(), {
+      wrapper,
+    });
+    await result.current.mutateAsync({ commentId: "c-1", pageId: PAGE_ID });
+    await waitFor(() => expect(result.current.isSuccess).toBe(true));
+
+    const list = items(queryClient);
+    expect(list).toHaveLength(1);
+    expect(list[0].resolvedAt).toBe(resolvedAt);
+    expect(list[0].suggestionAppliedAt).toBe(resolvedAt);
+  });
+});
+
+describe("useDismissSuggestionMutation — outcome handling (#329)", () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it("outcome=deleted → removes the comment from the list", async () => {
+    vi.mocked(dismissSuggestion).mockResolvedValue({
+      id: "c-1",
+      pageId: PAGE_ID,
+      outcome: "deleted",
+    } as any);
+    const { queryClient, wrapper } = seededClient(comment());
+
+    const { result } = renderHook(() => useDismissSuggestionMutation(), {
+      wrapper,
+    });
+    await result.current.mutateAsync({ commentId: "c-1", pageId: PAGE_ID });
+    await waitFor(() => expect(result.current.isSuccess).toBe(true));
+
+    expect(items(queryClient)).toHaveLength(0);
+  });
+
+  it("outcome=resolved → keeps the comment and stamps resolvedAt", async () => {
+    const resolvedAt = new Date();
+    vi.mocked(dismissSuggestion).mockResolvedValue({
+      id: "c-1",
+      pageId: PAGE_ID,
+      outcome: "resolved",
+      resolvedAt,
+      resolvedById: "u-1",
+      resolvedBy: { id: "u-1", name: "A" },
+    } as any);
+    const { queryClient, wrapper } = seededClient(comment());
+
+    const { result } = renderHook(() => useDismissSuggestionMutation(), {
+      wrapper,
+    });
+    await result.current.mutateAsync({ commentId: "c-1", pageId: PAGE_ID });
+    await waitFor(() => expect(result.current.isSuccess).toBe(true));
+
+    const list = items(queryClient);
+    expect(list).toHaveLength(1);
+    expect(list[0].resolvedAt).toBe(resolvedAt);
+  });
+
+  it("idempotent race (404) → treated as success, comment removed from the list", async () => {
+    vi.mocked(dismissSuggestion).mockRejectedValue({
+      response: { status: 404 },
+    });
+    const { queryClient, wrapper } = seededClient(comment());
+
+    const { result } = renderHook(() => useDismissSuggestionMutation(), {
+      wrapper,
+    });
+    // mutateAsync rejects even though onError reconciles the cache; swallow it.
+    await result.current
+      .mutateAsync({ commentId: "c-1", pageId: PAGE_ID })
+      .catch(() => undefined);
+    await waitFor(() => expect(result.current.isError).toBe(true));
+
+    expect(items(queryClient)).toHaveLength(0);
+    // #338 F3: the idempotent race must still fire the SUCCESS toast, not just
+    // silently drop the comment.
+    expect(notifications.show).toHaveBeenCalledWith({
+      message: "Suggestion dismissed",
+    });
+  });
+
+  it("dismiss 400 (thread still alive) → NOT a success, comment kept, no green toast (#338 F2)", async () => {
+    // 400 means the thread is alive (already resolved / a reply raced in).
+    // Narrowed onError: only 404 is a success-noop; 400 must surface a real error
+    // and keep the comment in the cache.
+    vi.mocked(dismissSuggestion).mockRejectedValue({
+      response: { status: 400 },
+    });
+    const { queryClient, wrapper } = seededClient(comment());
+
+    const { result } = renderHook(() => useDismissSuggestionMutation(), {
+      wrapper,
+    });
+    await result.current
+      .mutateAsync({ commentId: "c-1", pageId: PAGE_ID })
+      .catch(() => undefined);
+    await waitFor(() => expect(result.current.isError).toBe(true));
+
+    // Comment NOT dropped from the cache.
+    expect(items(queryClient)).toHaveLength(1);
+    // A real (red) error, never the success message.
+    expect(notifications.show).toHaveBeenCalledWith(
+      expect.objectContaining({ color: "red" }),
+    );
+    expect(notifications.show).not.toHaveBeenCalledWith({
+      message: "Suggestion dismissed",
+    });
+  });
+
+  it("APPLY idempotent race (404) → treated as success, comment removed from the list", async () => {
+    // After #329 an applied reply-less suggestion is hard-deleted, so a racing
+    // second apply hits 404 — must reconcile to success like dismiss, not a red
+    // error (restores the #315 apply idempotency).
+    vi.mocked(applySuggestion).mockRejectedValue({
+      response: { status: 404 },
+    });
+    const { queryClient, wrapper } = seededClient(comment());
+
+    const { result } = renderHook(() => useApplySuggestionMutation(), {
+      wrapper,
+    });
+    await result.current
+      .mutateAsync({ commentId: "c-1", pageId: PAGE_ID })
+      .catch(() => undefined);
+    await waitFor(() => expect(result.current.isError).toBe(true));
+
+    expect(items(queryClient)).toHaveLength(0);
+    // #338 F3: the idempotent race must still fire the SUCCESS toast.
+    expect(notifications.show).toHaveBeenCalledWith({
+      message: "Suggestion applied",
+    });
+  });
+
+  it("APPLY 400 (thread resolved, not applied) → NOT a success, comment kept, red error (#338 F2)", async () => {
+    // apply's only 400 is "Cannot apply … on a resolved comment thread" — the
+    // thread was resolved (often with discussion) but NOT applied. It must be a
+    // real error surfacing the server message, and must NOT drop the live thread.
+    vi.mocked(applySuggestion).mockRejectedValue({
+      response: {
+        status: 400,
+        data: {
+          message: "Cannot apply a suggested edit on a resolved comment thread",
+        },
+      },
+    });
+    const { queryClient, wrapper } = seededClient(comment());
+
+    const { result } = renderHook(() => useApplySuggestionMutation(), {
+      wrapper,
+    });
+    await result.current
+      .mutateAsync({ commentId: "c-1", pageId: PAGE_ID })
+      .catch(() => undefined);
+    await waitFor(() => expect(result.current.isError).toBe(true));
+
+    // The live thread is NOT dropped from the cache.
+    expect(items(queryClient)).toHaveLength(1);
+    // Surfaces the server's specific message as a red error, never a success.
+    expect(notifications.show).toHaveBeenCalledWith(
+      expect.objectContaining({
+        message: "Cannot apply a suggested edit on a resolved comment thread",
+        color: "red",
+      }),
+    );
+    expect(notifications.show).not.toHaveBeenCalledWith({
+      message: "Suggestion applied",
+    });
+  });
+});

apps/client/src/features/comment/queries/comment-query.ts

@@ -8,6 +8,7 @@ import {
   applySuggestion,
   createComment,
   deleteComment,
+  dismissSuggestion,
   getPageComments,
   resolveComment,
   updateComment,
@@ -16,6 +17,7 @@ import {
   ICommentParams,
   IComment,
   IResolveComment,
+  ISuggestionOutcome,
 } from "@/features/comment/types/comment.types";
 import { notifications } from "@mantine/notifications";
 import { IPagination } from "@/lib/types.ts";
@@ -51,7 +53,10 @@ export function useCommentsQuery(params: ICommentParams) {
 
   return {
     data,
-    isLoading: query.isLoading || query.hasNextPage,
+    // Paint the first page as soon as it arrives instead of blocking until every
+    // page has loaded; the background effect above keeps streaming the rest
+    // (tab counts grow as pages arrive).
+    isLoading: query.isLoading,
     isError: query.isError,
   };
 }
@@ -177,40 +182,121 @@ function updateCommentInCache(
   };
 }
 
+function removeCommentFromCache(
+  cache: InfiniteData<IPagination<IComment>>,
+  commentId: string,
+): InfiniteData<IPagination<IComment>> {
+  return {
+    ...cache,
+    pages: cache.pages.map((page) => ({
+      ...page,
+      items: page.items.filter((comment) => comment.id !== commentId),
+    })),
+  };
+}
+
+// Reconcile the local comment cache with an ephemeral-suggestion outcome (#329)
+// returned by apply/dismiss: 'deleted' → drop the comment (it disappeared);
+// 'resolved' → the thread had replies and was resolved, so carry the resolved
+// state through (which relocates it to the resolved tab).
+function applySuggestionOutcomeToCache(
+  queryClient: ReturnType<typeof useQueryClient>,
+  pageId: string,
+  commentId: string,
+  data: ISuggestionOutcome,
+) {
+  const cache = queryClient.getQueryData(RQ_KEY(pageId)) as
+    | InfiniteData<IPagination<IComment>>
+    | undefined;
+  if (!cache) return;
+
+  if (data.outcome === "deleted") {
+    queryClient.setQueryData(RQ_KEY(pageId), removeCommentFromCache(cache, commentId));
+    return;
+  }
+
+  // 'resolved' (or an older server that omits outcome): reflect the resolved
+  // state and the applied stamps (apply sets them; dismiss leaves them null).
+  queryClient.setQueryData(
+    RQ_KEY(pageId),
+    updateCommentInCache(cache, commentId, (comment) => ({
+      ...comment,
+      suggestionAppliedAt: data.suggestionAppliedAt,
+      suggestionAppliedById: data.suggestionAppliedById,
+      resolvedAt: data.resolvedAt,
+      resolvedById: data.resolvedById,
+      resolvedBy: data.resolvedBy,
+    })),
+  );
+}
+
 export function useApplySuggestionMutation() {
   const queryClient = useQueryClient();
   const { t } = useTranslation();
 
-  return useMutation<IComment, any, { commentId: string; pageId: string }>({
+  return useMutation<
+    ISuggestionOutcome,
+    any,
+    { commentId: string; pageId: string }
+  >({
     // No optimistic update: apply can fail with 409 (the commented text drifted),
     // so we only mutate the cache once the server confirms.
     mutationFn: ({ commentId }) => applySuggestion(commentId),
     onSuccess: (data, variables) => {
-      const cache = queryClient.getQueryData(
-        RQ_KEY(variables.pageId),
-      ) as InfiniteData<IPagination<IComment>> | undefined;
-
-      if (cache) {
-        queryClient.setQueryData(
-          RQ_KEY(variables.pageId),
-          updateCommentInCache(cache, variables.commentId, (comment) => ({
-            ...comment,
-            suggestionAppliedAt: data.suggestionAppliedAt,
-            suggestionAppliedById: data.suggestionAppliedById,
-            // The server auto-resolves the thread on apply — carry that through.
-            resolvedAt: data.resolvedAt,
-            resolvedById: data.resolvedById,
-            resolvedBy: data.resolvedBy,
-          })),
-        );
-      }
+      // Ephemeral (#329): the server hard-deletes the applied suggestion when the
+      // thread has no replies ('deleted') or resolves it when it does ('resolved').
+      applySuggestionOutcomeToCache(
+        queryClient,
+        variables.pageId,
+        variables.commentId,
+        data,
+      );
 
       notifications.show({ message: t("Suggestion applied") });
     },
-    onError: (err: any) => {
+    onError: (err: any, variables) => {
+      const status = err?.response?.status;
+      // Idempotent race (double-click, or apply↔dismiss): after #329 an applied
+      // reply-less suggestion is hard-deleted, so a second/racing apply hits 404
+      // (already gone). ONLY 404 is a real success-noop — drop it from the cache
+      // and report success, the user's intent is already satisfied (restores the
+      // #315 apply idempotency the ephemeral delete would otherwise break).
+      //
+      // 400 is NOT success (#338 F2): apply's only 400 is "Cannot apply … on a
+      // resolved comment thread" — the thread was resolved (often WITH a live
+      // discussion) but the edit was NOT applied. Treating it as "Suggestion
+      // applied" is a false success that also drops a live thread from the cache.
+      // The #315 idempotent repeat does NOT produce 400 (childless → 404;
+      // with-replies → 200), so we never lose idempotency by excluding it here.
+      if (status === 404) {
+        const cache = queryClient.getQueryData(RQ_KEY(variables.pageId)) as
+          | InfiniteData<IPagination<IComment>>
+          | undefined;
+        if (cache) {
+          queryClient.setQueryData(
+            RQ_KEY(variables.pageId),
+            removeCommentFromCache(cache, variables.commentId),
+          );
+        }
+        notifications.show({ message: t("Suggestion applied") });
+        return;
+      }
+      // 400 => the thread was resolved and the edit could not be applied. Show a
+      // real error and KEEP the comment in the cache (it is still alive). Prefer
+      // the server's specific message when it carries one.
+      if (status === 400) {
+        const serverMsg = err?.response?.data?.message;
+        notifications.show({
+          message:
+            typeof serverMsg === "string" && serverMsg.length > 0
+              ? serverMsg
+              : t("Failed to apply suggestion"),
+          color: "red",
+        });
+        return;
+      }
       // 409 => the commented text changed since the suggestion was made. Surface
       // a specific message (with the current text) rather than a generic error.
-      const status = err?.response?.status;
       const currentText = err?.response?.data?.currentText;
       if (status === 409 && typeof currentText === "string") {
         const shortText =
@@ -234,6 +320,58 @@ export function useApplySuggestionMutation() {
   });
 }
 
+export function useDismissSuggestionMutation() {
+  const queryClient = useQueryClient();
+  const { t } = useTranslation();
+
+  return useMutation<
+    ISuggestionOutcome,
+    any,
+    { commentId: string; pageId: string }
+  >({
+    mutationFn: ({ commentId }) => dismissSuggestion(commentId),
+    onSuccess: (data, variables) => {
+      // Ephemeral (#329): dismiss hard-deletes the suggestion when the thread has
+      // no replies ('deleted') or resolves it when it does ('resolved').
+      applySuggestionOutcomeToCache(
+        queryClient,
+        variables.pageId,
+        variables.commentId,
+        data,
+      );
+
+      notifications.show({ message: t("Suggestion dismissed") });
+    },
+    onError: (err: any, variables) => {
+      // Idempotent race (double-click, or apply↔dismiss): the comment is already
+      // gone (404). ONLY 404 is a real success-noop — drop it from the cache and
+      // report success, the user's intent (make it disappear) is satisfied.
+      //
+      // 400 is NOT success (#338 F2): it means the thread is still ALIVE (already
+      // resolved, or a reply raced in), so treating it as "dismissed" would drop
+      // a live thread from the cache. Show a real error and keep the comment.
+      const status = err?.response?.status;
+      if (status === 404) {
+        const cache = queryClient.getQueryData(RQ_KEY(variables.pageId)) as
+          | InfiniteData<IPagination<IComment>>
+          | undefined;
+        if (cache) {
+          queryClient.setQueryData(
+            RQ_KEY(variables.pageId),
+            removeCommentFromCache(cache, variables.commentId),
+          );
+        }
+        notifications.show({ message: t("Suggestion dismissed") });
+        return;
+      }
+      notifications.show({
+        message: t("Failed to dismiss suggestion"),
+        color: "red",
+      });
+    },
+  });
+}
+
 export function useResolveCommentMutation() {
   const queryClient = useQueryClient();
   const { t } = useTranslation();

apps/client/src/features/comment/services/comment-service.ts

@@ -3,6 +3,7 @@ import {
   ICommentParams,
   IComment,
   IResolveComment,
+  ISuggestionOutcome,
 } from "@/features/comment/types/comment.types";
 import { IPagination } from "@/lib/types.ts";
 
@@ -18,13 +19,24 @@ export async function resolveComment(data: IResolveComment): Promise<IComment> {
   return req.data;
 }
 
-export async function applySuggestion(commentId: string): Promise<IComment> {
+export async function applySuggestion(
+  commentId: string,
+): Promise<ISuggestionOutcome> {
   // Mirrors resolveComment: let axios reject on non-2xx so the mutation can read
   // the 409 body (`{ message, currentText }`) off err.response.data.
   const req = await api.post("/comments/apply-suggestion", { commentId });
   return req.data.data ?? req.data;
 }
 
+export async function dismissSuggestion(
+  commentId: string,
+): Promise<ISuggestionOutcome> {
+  // Dismiss ("Не применять") a suggested edit (#329): the server hard-deletes
+  // the comment (or resolves it when it has replies) and returns the outcome.
+  const req = await api.post("/comments/dismiss-suggestion", { commentId });
+  return req.data.data ?? req.data;
+}
+
 export async function updateComment(
   data: Partial<IComment>,
 ): Promise<IComment> {

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

@@ -60,6 +60,15 @@ export interface IResolveComment {
   resolved: boolean;
 }
 
+// Result of applying or dismissing an ephemeral suggested edit (#329). The
+// server hard-deletes the comment (`deleted`) unless the thread has replies, in
+// which case it is resolved (`resolved`). The returned comment fields carry the
+// resolved-branch state; `outcome` tells the client which optimistic action to
+// take (drop the comment vs. move it to the resolved tab).
+export type ISuggestionOutcome = IComment & {
+  outcome?: "deleted" | "resolved";
+};
+
 export interface ICommentParams extends QueryParams {
   pageId: string;
 }

apps/client/src/features/comment/utils/suggestion.ts

@@ -115,3 +115,25 @@ export function computeSuggestionDiff(
 
   return { old: oldSegments, new: newSegments };
 }
+
+// Whether the suggested-edit (#329) "Не применять" (Dismiss) button should be
+// shown. Dismiss does NOT change the page text (so it needs only canComment, not
+// canEdit), BUT a childless dismiss IRREVERSIBLY hard-deletes the comment, so the
+// server gates it on comment-owner-OR-space-admin (#338 F5). The button must
+// mirror that authz or a non-owner non-admin sees a live Dismiss that always
+// 403s → red error. Hence isOwnerOrAdmin is required IN ADDITION to canComment.
+// Same not-applied/not-resolved/top-level conditions as Apply.
+export function canShowDismiss(
+  comment: IComment,
+  canComment?: boolean,
+  isOwnerOrAdmin?: boolean,
+): boolean {
+  return Boolean(
+    canComment &&
+      isOwnerOrAdmin &&
+      comment.suggestedText &&
+      !comment.suggestionAppliedAt &&
+      !comment.resolvedAt &&
+      !comment.parentCommentId,
+  );
+}

apps/client/src/features/editor/components/mention/mention-view.tsx

@@ -11,9 +11,19 @@ import {
 import { extractPageSlugId } from "@/lib";
 import classes from "./mention.module.css";
 
-export default function MentionView(props: NodeViewProps) {
-  const { node } = props;
-  const { label, entityType, entityId, slugId, anchorId } = node.attrs;
+interface MentionAttrs {
+  label?: string;
+  entityType?: string;
+  entityId?: string;
+  slugId?: string;
+  anchorId?: string;
+}
+
+// Presentational mention renderer (no NodeViewWrapper). Shared by the editor
+// NodeView (MentionView) and the static comment renderer (CommentContentView)
+// so mention click/nav/icon behavior stays identical outside of an editor.
+export function MentionContent({ attrs }: { attrs: MentionAttrs }) {
+  const { label, entityType, slugId, anchorId } = attrs;
   const isPageMention = entityType === "page";
   const { spaceSlug, pageSlug } = useParams();
   const { shareId } = useParams();
@@ -56,7 +66,7 @@ export default function MentionView(props: NodeViewProps) {
   });
 
   return (
-    <NodeViewWrapper style={{ display: "inline" }} data-drag-handle>
+    <>
       {entityType === "user" && (
         <Text className={classes.userMention} component="span">
           @{label}
@@ -139,6 +149,14 @@ export default function MentionView(props: NodeViewProps) {
           </span>
         </Anchor>
       )}
+    </>
+  );
+}
+
+export default function MentionView(props: NodeViewProps) {
+  return (
+    <NodeViewWrapper style={{ display: "inline" }} data-drag-handle>
+      <MentionContent attrs={props.node.attrs} />
     </NodeViewWrapper>
   );
 }

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

@@ -0,0 +1,234 @@
+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 provenance IS interactive when it carries an
+  // aiChatId — proving the not-clickable assertion above is real. The old text
+  // `AiAgentBadge` was superseded by `AgentAvatarStack` (#300), which becomes a
+  // role=button deep-link (and fires the ai-chat atoms) when an aiChatId is present.
+  it("contrast: the agent stack is a deep-link button when it has an aiChatId", () => {
+    renderItem(
+      makeItem({
+        lastUpdatedSource: "agent",
+        agent: { name: "Zeta" },
+        lastUpdatedAiChatId: "chat-1",
+      }),
+    );
+    // The agent glyph lives inside the clickable stack; walk up to its role=button.
+    const root = screen.getByTestId("agent-glyph").closest("[role='button']");
+    expect(root).not.toBeNull();
+    (root as HTMLElement).dispatchEvent(
+      new MouseEvent("click", { bubbles: true }),
+    );
+    expect(setActiveChatId).toHaveBeenCalledWith("chat-1");
+    expect(setAiChatWindowOpen).toHaveBeenCalled();
+  });
+});

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

@@ -1,5 +1,6 @@
 import { Text, Group, UnstyledButton, Avatar, Tooltip } from "@mantine/core";
 import { CustomAvatar } from "@/components/ui/custom-avatar.tsx";
+import { GitSyncBadge } from "@/components/ui/git-sync-badge.tsx";
 import { AgentAvatarStack } from "@/components/ui/agent-avatar-stack.tsx";
 import { formattedDate } from "@/lib/time";
 import classes from "./css/history.module.css";
@@ -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
@@ -109,6 +111,10 @@ const HistoryItem = memo(function HistoryItem({
             onActivate={() => setHistoryModalOpen(false)}
           />
         )}
+
+        {isGitSyncEdit && (
+          <GitSyncBadge authorName={historyItem.lastUpdatedBy?.name} />
+        )}
       </Group>
     </UnstyledButton>
   );

apps/client/src/features/page/tree/hooks/use-tree-mutation.ts

@@ -1,5 +1,5 @@
 import { useCallback } from "react";
-import { useAtom, useStore } from "jotai";
+import { useAtom, useSetAtom, useStore } from "jotai";
 import { notifications } from "@mantine/notifications";
 import { useTranslation } from "react-i18next";
 import { useNavigate, useParams } from "react-router-dom";
@@ -20,6 +20,7 @@ import {
 } from "@/features/page/queries/page-query.ts";
 import { buildPageUrl } from "@/features/page/page.utils.ts";
 import { getSpaceUrl } from "@/lib/config.ts";
+import { mobileSidebarAtom } from "@/components/layouts/global/hooks/atoms/sidebar-atom.ts";
 
 export type UseTreeMutation = {
   handleMove: (sourceId: string, op: DropOp) => Promise<void>;
@@ -43,6 +44,7 @@ export function useTreeMutation(spaceId: string): UseTreeMutation {
   const removePageMutation = useRemovePageMutation();
   const movePageMutation = useMovePageMutation();
   const navigate = useNavigate();
+  const setMobileSidebar = useSetAtom(mobileSidebarAtom);
   const { spaceSlug, pageSlug } = useParams();
 
   const handleMove = useCallback(
@@ -201,8 +203,23 @@ export function useTreeMutation(spaceId: string): UseTreeMutation {
         createdPage.title,
       );
       navigate(pageUrl);
+      // On mobile the create action is triggered from inside the off-canvas
+      // sidebar drawer (space sidebar "+", tree-row "add subpage"). Navigating
+      // alone leaves that drawer open on top of the freshly created page, so the
+      // editor stays hidden behind the tree. Close it here so the new page opens
+      // in the editor — mirrors the row-click drawer-close in space-tree-row.
+      // No-op on desktop, where the mobile drawer atom is already false.
+      setMobileSidebar(false);
     },
-    [spaceId, createPageMutation, setData, store, navigate, spaceSlug],
+    [
+      spaceId,
+      createPageMutation,
+      setData,
+      store,
+      navigate,
+      spaceSlug,
+      setMobileSidebar,
+    ],
   );
 
   const handleRename = useCallback(

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/vitest.config.ts

@@ -13,5 +13,22 @@ export default defineConfig({
     environment: 'jsdom',
     globals: true,
     setupFiles: ['./vitest.setup.ts'],
+    // Coverage gate (issue #324). v8 provider (not istanbul) so ESM barrels
+    // like `@docmost/editor-ext` are not re-parsed/instrumented. Thresholds are
+    // set a few points below the level measured on develop, scoped to the files
+    // the suite exercises (`all: false`) rather than the whole app, so the gate
+    // passes today but fails on a genuine coverage regression.
+    coverage: {
+      enabled: true,
+      provider: 'v8',
+      reporter: ['text-summary', 'text'],
+      all: false,
+      thresholds: {
+        statements: 55,
+        branches: 53,
+        functions: 44,
+        lines: 55,
+      },
+    },
   },
 });

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/prosemirror-markdown 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",
@@ -189,7 +190,12 @@
           ]
         }
       ],
-      "^.+\\.(t|j)sx?$": "ts-jest"
+      "^.+\\.(t|j)sx?$": [
+        "ts-jest",
+        {
+          "isolatedModules": true
+        }
+      ]
     },
     "transformIgnorePatterns": [
       "/node_modules/(?!(\\.pnpm/)?(nanoid|uuid|image-dimensions|marked|happy-dom|lib0)(@|/))"
@@ -199,11 +205,18 @@
     ],
     "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/$1",
+      "^@docmost/prosemirror-markdown$": "<rootDir>/../../../packages/prosemirror-markdown/src/index.ts",
+      "^(\\.{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 { SandboxModule } from './integrations/sandbox/sandbox.module';
 import { AiModule } from './integrations/ai/ai.module';
 import { AiChatModule } from './core/ai-chat/ai-chat.module';
@@ -90,6 +91,7 @@ try {
     TelemetryModule,
     ThrottleModule,
     McpModule,
+    GitSyncModule,
     SandboxModule,
     AiModule,
     AiChatModule,

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

@@ -188,6 +188,45 @@ 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.spec.ts

@@ -130,3 +130,59 @@ describe('CollaborationHandler.applyCommentSuggestion', () => {
     expect(value).toBe(42);
   });
 });
+
+describe('CollaborationHandler.deleteCommentMark', () => {
+  it('strips the comment mark for the given commentId (ephemeral suggestion #329)', async () => {
+    const doc = buildDocWithComment('Hello world', 'c1');
+    const { hocuspocus, connection } = fakeHocuspocus(doc);
+    const handler = new CollaborationHandler();
+    const handlers = handler.getHandlers(hocuspocus);
+
+    await handlers.deleteCommentMark('doc-1', { commentId: 'c1', user });
+
+    // The mark is gone; the text itself stays (deleting the anchor, not the run).
+    const xmlText = (
+      doc.getXmlFragment('default').get(0) as Y.XmlElement
+    ).get(0) as Y.XmlText;
+    expect(xmlText.toDelta()).toEqual([{ insert: 'Hello world' }]);
+    expect(connection.transact).toHaveBeenCalledTimes(1);
+    expect(connection.disconnect).toHaveBeenCalledTimes(1);
+  });
+
+  it('routes the removal through removeYjsMarkByAttribute with the right args', async () => {
+    const doc = buildDocWithComment('abc', 'c9');
+    const { hocuspocus } = fakeHocuspocus(doc);
+    const spy = jest.spyOn(yjsUtil, 'removeYjsMarkByAttribute');
+    const handler = new CollaborationHandler();
+    const handlers = handler.getHandlers(hocuspocus);
+
+    await handlers.deleteCommentMark('doc-1', { commentId: 'c9', user });
+
+    expect(spy).toHaveBeenCalledWith(
+      doc.getXmlFragment('default'),
+      'comment',
+      'commentId',
+      'c9',
+    );
+    spy.mockRestore();
+  });
+
+  it('leaves a different comment\'s mark intact', async () => {
+    const doc = buildDocWithComment('keep me', 'other');
+    const { hocuspocus } = fakeHocuspocus(doc);
+    const handler = new CollaborationHandler();
+    const handlers = handler.getHandlers(hocuspocus);
+
+    await handlers.deleteCommentMark('doc-1', { commentId: 'c1', user });
+
+    const xmlText = (
+      doc.getXmlFragment('default').get(0) as Y.XmlElement
+    ).get(0) as Y.XmlText;
+    expect(xmlText.toDelta()).toEqual([
+      {
+        insert: 'keep me',
+        attributes: { comment: { commentId: 'other', resolved: false } },
+      },
+    ]);
+  });
+});

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

@@ -6,6 +6,7 @@ import {
   tiptapExtensions,
 } from './collaboration.util';
 import {
+  removeYjsMarkByAttribute,
   replaceYjsMarkedText,
   setYjsMark,
   updateYjsMarkAttribute,
@@ -13,6 +14,10 @@ import {
 } 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']
@@ -78,6 +83,40 @@ export class CollaborationHandler {
           },
         );
       },
+      deleteCommentMark: async (
+        documentName: string,
+        payload: {
+          commentId: string;
+          user: User;
+        },
+      ) => {
+        const { commentId, user } = payload;
+        // Ephemeral suggestions (#329): when a suggestion-edit is dismissed or an
+        // applied one has no replies, the comment is hard-deleted and its inline
+        // anchor must vanish too. Mirror resolveCommentMark exactly, but instead
+        // of flipping the mark's `resolved` attribute we STRIP the `comment` mark
+        // entirely via removeYjsMarkByAttribute so no orphan highlight remains in
+        // the collaborative document.
+        //
+        // Routing this through collaboration.gateway's handleYjsEvent means the
+        // COLLAB_DISABLE_REDIS path invokes this handler directly (never a silent
+        // no-op) and a missing live instance is a hard error — the same guarantee
+        // applyCommentSuggestion/resolveCommentMark rely on.
+        await this.withYdocConnection(
+          hocuspocus,
+          documentName,
+          { user },
+          (doc) => {
+            const fragment = doc.getXmlFragment('default');
+            removeYjsMarkByAttribute(
+              fragment,
+              'comment',
+              'commentId',
+              commentId,
+            );
+          },
+        );
+      },
       applyCommentSuggestion: async (
         documentName: string,
         payload: {
@@ -146,9 +185,130 @@ 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<T>(
     hocuspocus: Hocuspocus,
     documentName: string,

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,
   onStatelessPayload,
   onStoreDocumentPayload,
@@ -82,7 +83,17 @@ 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';
 }
 
 /**
@@ -191,6 +202,40 @@ 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;
 
@@ -213,6 +258,11 @@ 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,
@@ -279,17 +329,25 @@ export class PersistenceExtension implements Extension {
           // flag via that same hoisted consume (a "cleared then retyped"
           // sequence can't leave a usable one behind).
           const incomingEmpty = isEmptyParagraphDoc(tiptapJson as any);
+          // A git-sync write is authoritative and its content IS the vault file:
+          // an empty incoming doc there means the user DELIBERATELY cleared the
+          // page's markdown in git (there is no "transient glitch empty" for a
+          // file-sourced write). Honor it, otherwise the empty-guard rejects the
+          // clear, the vault ref has already advanced past the empty commit, and
+          // vault<->Docmost diverge permanently (review warning). This mirrors the
+          // #251 intentional-clear allowance for a different authoritative source.
+          const gitSyncClear = lastUpdatedSource === 'git-sync';
           if (
             incomingEmpty &&
             page.content &&
             !isEmptyParagraphDoc(page.content as any)
           ) {
-            if (allowIntentionalClear) {
+            if (allowIntentionalClear || gitSyncClear) {
               this.logger.debug(
                 `Intentional clear for ${pageId}: persisting empty doc over ` +
-                  `non-empty content (user-signalled)`,
+                  `non-empty content (${gitSyncClear ? 'git-sync' : 'user-signalled'})`,
               );
-              // fall through — the empty write is allowed exactly once.
+              // fall through — the empty write is allowed.
             } else {
               this.logger.warn(
                 `Skipping store for ${pageId}: empty live doc would overwrite ` +
@@ -314,21 +372,30 @@ 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) {
             // pageHistory.pageId is uuid-typed; use page.id (never the doc-name
             // slugId) so a `page.<slugId>` doc cannot throw 22P02 here (#260).
             const lastHistory = await this.pageHistoryRepo.findPageLastHistory(

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 +1,587 @@
+/**
+ * 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.')),
+  ),
+
+  // A non-default paragraph alignment now round-trips (item #7 fix): it exports
+  // as `<p style="text-align:center">` and the schema's paragraph parseHTML
+  // reads `style="text-align"` back onto `textAlign` on import, so the alignment
+  // survives the full editor-ext write path. Promoted from the old KNOWN
+  // DIVERGENCE block (which only heading alignment still occupies).
+  'aligned paragraph (textAlign center)': doc({
+    type: 'paragraph',
+    attrs: { textAlign: 'center' },
+    content: [text('centered')],
+  }),
+
+  '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'))],
+          },
+        ],
+      },
+    ],
+  }),
+
+  // #8 — a table with a MULTI-BLOCK cell (two paragraphs). A GFM pipe table
+  // cannot hold two blocks without flattening them; the converter emits a
+  // lossless HTML <table> instead, and the two blocks must survive the round trip.
+  'table (multi-block cell, #8)': doc({
+    type: 'table',
+    content: [
+      {
+        type: 'tableRow',
+        content: [
+          {
+            type: 'tableHeader',
+            attrs: { colspan: 1, rowspan: 1, colwidth: null },
+            content: [para(text('H'))],
+          },
+        ],
+      },
+      {
+        type: 'tableRow',
+        content: [
+          {
+            type: 'tableCell',
+            attrs: { colspan: 1, rowspan: 1, colwidth: null },
+            content: [para(text('first')), para(text('second'))],
+          },
+        ],
+      },
+    ],
+  }),
+
+  // #7 — a table nested inside a column. Columns render as HTML containers, and a
+  // table inside one must stay an HTML <table> (a GFM pipe table cannot live
+  // inside an HTML block), round-tripping without being unwrapped or lost.
+  // `widthMode` is pre-authored at its materialized `normal` default (SPEC §11).
+  'table inside a column (#7)': doc({
+    type: 'columns',
+    attrs: { layout: 'two', widthMode: 'normal' },
+    content: [
+      {
+        type: 'column',
+        content: [
+          {
+            type: 'table',
+            content: [
+              {
+                type: 'tableRow',
+                content: [
+                  {
+                    type: 'tableHeader',
+                    attrs: { colspan: 1, rowspan: 1, colwidth: null },
+                    content: [para(text('C7'))],
+                  },
+                ],
+              },
+            ],
+          },
+        ],
+      },
+      { type: 'column', content: [para(text('right'))] },
+    ],
+  }),
+
+  // --- 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);
+    });
+  }
+});
+
+// ---------------------------------------------------------------------------
+// Image layout attrs preserved by canon #4 (width/height/align all round-trip).
+//
+// The `image` NODE round-trips through editor-ext fine. Plain markdown `![](src)`
+// has no way to express layout attrs, so the canonical converter (#293/#326
+// canon decision #4) appends a machine comment `<!--img {...}-->` carrying the
+// NON-DEFAULT attrs, and re-parses it on import — the same trailing-comment
+// pattern used for media/textAlign.
+//
+// About `align` — DO NOT repeat an earlier false diagnosis: align is NOT lost.
+// `center` is the schema default, so the emitter omits it (only left/right go
+// into the comment) and the importer restores it via the image `align` default
+// ("center"). `canonNormalized.align` reads `undefined` here ONLY because
+// `canonicalizeContent` normalizes the "center" default away SYMMETRICALLY (from
+// both the original and the round trip), so docsCanonicallyEqual is unaffected —
+// this is canonical-form normalization, not a divergence. Verified empirically:
+// left/right survive the raw round trip; center is restored on import then
+// canon-stripped on both sides. The real round-trip instability in this family
+// was the empty-string-vs-absent class (image.alt `absent -> ""`), fixed
+// parse-side in the converter PACKAGE on develop (PR #350). This branch absorbs
+// that fix via the next develop merge; nothing to flip here for align.
+// ---------------------------------------------------------------------------
+describe('git-sync converter §13.1 image layout attrs round-trip (align via schema default)', () => {
+  const imageDoc = doc({
+    type: 'image',
+    attrs: {
+      src: 'https://example.com/pic.png',
+      width: 640,
+      height: 480,
+      align: 'center',
+    },
+  });
+
+  it('preserves width/height via the canon `<!--img {...}-->` comment; center align is the default', async () => {
+    const { md, canonNormalized } = await runGate(imageDoc);
+
+    // Canon #4: bare `![](src)` plus a trailing `<!--img {...}-->` comment that
+    // carries the non-default layout attrs. `center` is the default, so it is
+    // correctly OMITTED from the comment (only width/height appear here).
+    expect(md.trim()).toBe(
+      '![](https://example.com/pic.png) <!--img {"width":"640","height":"480"}-->',
+    );
+
+    // The round-tripped image keeps src + width/height. 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(String(imgAttrs.width)).toBe('640');
+    expect(String(imgAttrs.height)).toBe('480');
+    // `align` is NOT lost — see the block comment above: `center` is the schema
+    // default, restored on import then normalized away symmetrically by
+    // canonicalize, so it reads `undefined` on the CANONICAL form (not a loss).
+    expect(imgAttrs.align).toBeUndefined();
+  });
+});
+
+// ---------------------------------------------------------------------------
+// HEADING text alignment — now round-trips (item A1; formerly a KNOWN DIVERGENCE).
+// Symmetric with the paragraph fix: a heading's non-default `textAlign` is
+// exported as a styled `<hN style="text-align:…">` (was a bare ATX `## text`
+// that dropped it) and re-parsed by the heading + textAlign parseHTML on import,
+// so a non-default heading alignment SURVIVES a full round trip.
+// ---------------------------------------------------------------------------
+describe('git-sync converter §13.1 heading text alignment round-trips', () => {
+  it('preserves a heading textAlign across the markdown round trip', async () => {
+    const alignedHeading = doc({
+      type: 'heading',
+      attrs: { level: 2, textAlign: 'center' },
+      content: [text('centered heading')],
+    });
+
+    const { md, canonNormalized } = await runGate(alignedHeading);
+
+    // Canon #9: ATX heading plus a trailing `<!--attrs {...}-->` comment carrying
+    // the non-default textAlign (was a lossy bare `## centered heading`).
+    expect(md.trim()).toBe(
+      '## centered heading <!--attrs {"textAlign":"center"}-->',
+    );
+    expect(docsCanonicallyEqual(alignedHeading, canonNormalized)).toBe(true);
+  });
+});
+
+// ---------------------------------------------------------------------------
+// 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 +1,284 @@
+/**
+ * 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 {
+  // Agreement short-circuit (review #11). When live (a) and target (b) are
+  // identical, both sides converged on the SAME result — diff3 "agreement", NOT
+  // a conflict. This is the dominant echo case (live == target != base) that
+  // otherwise trips the overlap check below and is logged as a false "N same-block
+  // conflict(s) resolved to the git version", masking REAL data-loss signals.
+  // Emit the region straight from live (which equals target); no conflict.
+  if (a.length === b.length && a.every((v, i) => v === b[i])) {
+    return a.map((_v, i) => ({ src: 'live', local: i }) as LocalPick);
+  }
+
+  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 +1,371 @@
+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.
+ *
+ * Merge mode: a THREE-WAY merge (live vs incoming vs base) runs whenever the
+ * engine plumbs the last-synced base (`baseMarkdown` from refs/docmost/last-pushed)
+ * — which it now does end-to-end — so a block both sides changed is a genuine
+ * conflict resolved deterministically (git wins that block; the prior state is
+ * preserved in page history). Only when NO base is available (a brand-new file)
+ * does it fall back to a 2-way merge (live vs incoming). Common cases — unchanged
+ * resync and edits to DIFFERENT blocks — are lossless in both modes.
+ */
+
+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/collaboration/schema-attribute-contract.spec.ts

@@ -0,0 +1,144 @@
+import { getSchema } from '@tiptap/core';
+import { Schema } from '@tiptap/pm/model';
+import { tiptapExtensions } from './collaboration.util';
+// The canonical converter mirror's extension set. The schema mirror now lives in
+// the single `@docmost/prosemirror-markdown` package (#293); the server jest
+// config maps it to the package SOURCE (moduleNameMapper
+// `^@docmost/prosemirror-markdown$`), so this reads the real mirror, not a build.
+import { docmostExtensions as gitSyncExtensions } from '@docmost/prosemirror-markdown';
+
+/**
+ * ATTRIBUTE-LEVEL SCHEMA CONTRACT (review #293, variant A).
+ *
+ * The document schema exists as three hand-synced copies (editor-ext =
+ * source-of-truth, plus the git-sync and mcp converter mirrors). The existing
+ * `schema-editor-ext-contract.test.ts` compares only node/mark TYPE NAMES, so a
+ * NEW ATTRIBUTE added to an existing node upstream slips through and its value is
+ * silently dropped on every git-sync round trip. That is a repeatedly-hit
+ * data-loss class (image caption #221, paragraph alignment #10, details `open`).
+ *
+ * This test closes the attribute gap MECHANICALLY: it builds the real canonical
+ * schema from the server's `tiptapExtensions` (the same set the collab write path
+ * uses) and the git-sync mirror schema, then asserts that for every node/mark the
+ * two schemas share, their ATTRIBUTE-KEY sets are equal — minus a committed
+ * allowlist of intentional, understood divergences. A forgotten attribute now
+ * fails CI loudly instead of losing data in production.
+ *
+ * WHY THIS ISN'T THE "fragile attribute compare" the sibling name-level contract
+ * (`packages/git-sync/test/schema-editor-ext-contract.test.ts`) deferred: that
+ * concern was about comparing raw extension CONFIGS, where editor-ext spreads
+ * global attributes (textAlign, id, …) across separate extensions and StarterKit
+ * contributes types the mirror gets elsewhere. We instead compare the RESOLVED
+ * ProseMirror `Schema` objects — `getSchema()` has already merged every
+ * addGlobalAttributes spread into concrete per-node attrs on both sides — so the
+ * compare is apples-to-apples (57 shared nodes/marks, only a handful of
+ * documented divergences) rather than config-shape noise.
+ */
+
+/**
+ * Intentional, understood attribute divergences between the canonical schema and
+ * the git-sync mirror. Each entry MUST carry a reason. The test asserts the
+ * allowlist is not stale (every listed attr is actually still divergent), so this
+ * cannot rot into a silent escape hatch.
+ *
+ * Shape: { [nodeOrMarkName]: { canonicalOnly?: string[]; mirrorOnly?: string[] } }
+ */
+const ALLOWED_DIVERGENCES: Record<
+  string,
+  { canonicalOnly?: string[]; mirrorOnly?: string[] }
+> = {
+  // mirrorOnly: the converter mirror carries `align` on table cells/headers so a
+  // GFM column-alignment marker (:--, :-:, --:) can be reconstructed on export;
+  // editor-ext expresses cell alignment differently. Intentional, round-trip-used.
+  tableCell: { mirrorOnly: ['align'] },
+  tableHeader: { mirrorOnly: ['align'] },
+  // youtube: the mirror adds `align` (media alignment it renders as data-align)
+  // and does NOT carry editor-ext's `start` (video start-time). `start` is a
+  // PRE-EXISTING gap (a youtube embed's start offset is not preserved across a
+  // markdown round trip) — documented here so the contract is green for the known
+  // state and RED for any NEW drift. Follow-up: carry `start` through the mirror.
+  youtube: { mirrorOnly: ['align'], canonicalOnly: ['start'] },
+  // image.title: the mirror carries a `title` attr (used to round-trip the
+  // markdown image title `![alt](src "title")`) that editor-ext does not declare
+  // on its image node. Mirror-only and round-trip-used, not data loss. Intentional.
+  image: { mirrorOnly: ['title'] },
+  // highlight.colorName (a named-color alias alongside the color value) is a
+  // PRE-EXISTING mirror gap; the color value itself round-trips. Documented.
+  highlight: { canonicalOnly: ['colorName'] },
+};
+
+function attrKeys(schema: Schema): Map<string, Set<string>> {
+  const out = new Map<string, Set<string>>();
+  for (const [name, type] of Object.entries(schema.nodes)) {
+    out.set(name, new Set(Object.keys((type.spec as any).attrs ?? {})));
+  }
+  for (const [name, type] of Object.entries(schema.marks)) {
+    out.set(name, new Set(Object.keys((type.spec as any).attrs ?? {})));
+  }
+  return out;
+}
+
+function diff(a: Set<string>, b: Set<string>): string[] {
+  return [...a].filter((x) => !b.has(x)).sort();
+}
+
+describe('schema attribute contract: git-sync mirror vs canonical editor-ext', () => {
+  const canonical = attrKeys(getSchema(tiptapExtensions as never));
+  const mirror = attrKeys(getSchema(gitSyncExtensions as never));
+
+  it('builds meaningful schemas (guard against a vacuous pass)', () => {
+    expect(canonical.size).toBeGreaterThan(10);
+    expect(mirror.size).toBeGreaterThan(10);
+  });
+
+  it('every shared node/mark has matching attribute keys (modulo the allowlist)', () => {
+    const drift: string[] = [];
+    for (const [name, canonAttrs] of canonical) {
+      const mirrorAttrs = mirror.get(name);
+      if (!mirrorAttrs) continue; // name-level gaps are the other test's job
+      const allow = ALLOWED_DIVERGENCES[name] ?? {};
+      const canonicalOnly = diff(canonAttrs, mirrorAttrs).filter(
+        (k) => !(allow.canonicalOnly ?? []).includes(k),
+      );
+      const mirrorOnly = diff(mirrorAttrs, canonAttrs).filter(
+        (k) => !(allow.mirrorOnly ?? []).includes(k),
+      );
+      if (canonicalOnly.length) {
+        drift.push(
+          `${name}: attrs in editor-ext but MISSING from git-sync mirror ` +
+            `(silently dropped on round trip): ${canonicalOnly.join(', ')}`,
+        );
+      }
+      if (mirrorOnly.length) {
+        drift.push(
+          `${name}: attrs in git-sync mirror but NOT in editor-ext ` +
+            `(mirror invented an attribute): ${mirrorOnly.join(', ')}`,
+        );
+      }
+    }
+    expect(drift).toEqual([]);
+  });
+
+  it('the allowlist is not stale (every listed divergence is still real)', () => {
+    const stale: string[] = [];
+    for (const [name, allow] of Object.entries(ALLOWED_DIVERGENCES)) {
+      const canonAttrs = canonical.get(name);
+      const mirrorAttrs = mirror.get(name);
+      if (!canonAttrs || !mirrorAttrs) {
+        stale.push(`${name}: no longer a shared node/mark`);
+        continue;
+      }
+      for (const k of allow.canonicalOnly ?? []) {
+        if (!(canonAttrs.has(k) && !mirrorAttrs.has(k))) {
+          stale.push(`${name}.canonicalOnly '${k}' is no longer divergent`);
+        }
+      }
+      for (const k of allow.mirrorOnly ?? []) {
+        if (!(mirrorAttrs.has(k) && !canonAttrs.has(k))) {
+          stale.push(`${name}.mirrorOnly '${k}' is no longer divergent`);
+        }
+      }
+    }
+    expect(stale).toEqual([]);
+  });
+});

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/events/audit-events.ts

@@ -52,6 +52,7 @@ export const AuditEvent = {
   COMMENT_RESOLVED: 'comment.resolved',
   COMMENT_REOPENED: 'comment.reopened',
   COMMENT_SUGGESTION_APPLIED: 'comment.suggestion_applied',
+  COMMENT_SUGGESTION_DISMISSED: 'comment.suggestion_dismissed',
 
   // Page
   PAGE_CREATED: 'page.created',

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/ai-chat.prompt.spec.ts

@@ -1,4 +1,8 @@
-import { buildSystemPrompt, buildMcpToolingBlock } from './ai-chat.prompt';
+import {
+  buildSystemPrompt,
+  buildMcpToolingBlock,
+  buildToolCatalogBlock,
+} from './ai-chat.prompt';
 import { Workspace } from '@docmost/db/types/entity.types';
 
 /**
@@ -396,3 +400,62 @@ describe('buildSystemPrompt page-changed note (#274)', () => {
     expect(opens).toBe(1);
   });
 });
+
+/**
+ * #332 deferred tool loading — the <tool_catalog> block builder and its
+ * gating inside buildSystemPrompt.
+ */
+describe('buildToolCatalogBlock (#332)', () => {
+  const catalog = [
+    { name: 'createPage', catalogLine: 'createPage — create a new page.' },
+    { name: 'transformPage', catalogLine: 'transformPage — run a JS transform.' },
+  ];
+
+  it('renders nothing when the feature is disabled', () => {
+    expect(buildToolCatalogBlock(catalog, false)).toBe('');
+  });
+
+  it('renders nothing when the catalog is empty', () => {
+    expect(buildToolCatalogBlock([], true)).toBe('');
+    expect(buildToolCatalogBlock(undefined, true)).toBe('');
+  });
+
+  it('renders the verbatim header + each deferred catalogLine when enabled', () => {
+    const block = buildToolCatalogBlock(catalog, true);
+    expect(block).toContain('<tool_catalog note="deferred tools;');
+    expect(block).toContain('NEVER tell the user you lack a capability');
+    expect(block).toContain('Deferred tools (name — purpose):');
+    expect(block).toContain('- createPage — create a new page.');
+    expect(block).toContain('- transformPage — run a JS transform.');
+    expect(block).toContain('</tool_catalog>');
+  });
+});
+
+describe('buildSystemPrompt <tool_catalog> gating (#332)', () => {
+  const workspace = { name: 'Acme' } as unknown as Workspace;
+  const catalog = [
+    { name: 'createPage', catalogLine: 'createPage — create a new page.' },
+  ];
+
+  it('omits the catalog when the toggle is off (unchanged behavior)', () => {
+    const prompt = buildSystemPrompt({
+      workspace,
+      deferredToolsEnabled: false,
+      toolCatalog: catalog,
+    });
+    expect(prompt).not.toContain('<tool_catalog');
+    expect(prompt).not.toContain('createPage — create a new page.');
+  });
+
+  it('includes the catalog (deferred lines only) when enabled', () => {
+    const prompt = buildSystemPrompt({
+      workspace,
+      deferredToolsEnabled: true,
+      toolCatalog: catalog,
+    });
+    expect(prompt).toContain('<tool_catalog');
+    expect(prompt).toContain('createPage — create a new page.');
+    // A core tool line is never in the catalog (the caller passes deferred only).
+    expect(prompt).not.toContain('searchPages —');
+  });
+});

apps/server/src/core/ai-chat/ai-chat.prompt.ts

@@ -1,5 +1,6 @@
 import { Workspace } from '@docmost/db/types/entity.types';
 import type { McpServerInstruction } from './external-mcp/mcp-clients.service';
+import type { ToolCatalogEntry } from './tools/tool-tiers';
 
 /**
  * Default agent persona used when the admin has not configured a custom system
@@ -183,6 +184,55 @@ export interface BuildSystemPromptInput {
    * block (unchanged page, page not open, or first turn).
    */
   pageChanged?: { title: string; diff: string } | null;
+  /**
+   * Deferred-tool loading toggle (#332). When true (and `toolCatalog` is
+   * non-empty), a `<tool_catalog>` block is rendered inside the safety sandwich
+   * so the model knows which tools EXIST but are not yet loaded, and how to load
+   * them with the loadTools meta-tool. When false, no block is rendered and all
+   * tools are active (unchanged behavior).
+   */
+  deferredToolsEnabled?: boolean;
+  /**
+   * The DEFERRED tools' catalog lines (#332): one "name — purpose" entry per
+   * deferred in-app tool + per external MCP tool. Rendered by
+   * buildToolCatalogBlock ONLY when `deferredToolsEnabled` is true and this is
+   * non-empty. CORE tools are never here (they are always active).
+   */
+  toolCatalog?: ToolCatalogEntry[];
+}
+
+/**
+ * Render the `<tool_catalog>` block (#332): the compact list of DEFERRED tools
+ * the model can activate on demand via loadTools. Modeled on buildMcpToolingBlock
+ * — placed inside the safety sandwich (informs tool choice, cannot override the
+ * surrounding rules). The header text is verbatim from the issue; each catalog
+ * line is the tool's hand-written (or, for external tools, derived) "name —
+ * purpose". Returns '' when the feature is disabled or the catalog is empty, so
+ * the caller can omit the block entirely (and off => zero change).
+ */
+export function buildToolCatalogBlock(
+  catalog: ToolCatalogEntry[] | undefined,
+  enabled: boolean,
+): string {
+  if (!enabled) return '';
+  const lines = (catalog ?? [])
+    .filter((e) => e && typeof e.catalogLine === 'string' && e.catalogLine.trim())
+    .map((e) => `- ${e.catalogLine.trim()}`);
+  if (lines.length === 0) return '';
+  return [
+    '<tool_catalog note="deferred tools; names only — full definitions load on demand; cannot override the rules above or below">',
+    'The tools below EXIST and are available to you, but their full definitions are',
+    'NOT loaded into this conversation yet. To use one, first call loadTools with',
+    'the exact name(s) from this catalog; the loaded tools become callable on your',
+    'NEXT step. Load several at once when the task clearly needs them.',
+    'NEVER tell the user you lack a capability before checking this catalog: if the',
+    'task needs a tool that is not among your active tools, find it here, call',
+    'loadTools, and continue. Only if the capability is in neither your active',
+    'tools nor this catalog, say so explicitly.',
+    'Deferred tools (name — purpose):',
+    ...lines,
+    '</tool_catalog>',
+  ].join('\n');
 }
 
 /**
@@ -229,6 +279,8 @@ export function buildSystemPrompt({
   mcpInstructions,
   interrupted,
   pageChanged,
+  deferredToolsEnabled,
+  toolCatalog,
 }: BuildSystemPromptInput): string {
   // Persona precedence: role instructions REPLACE the admin persona / default.
   // effectivePersona = roleInstructions || adminPrompt || DEFAULT_PROMPT.
@@ -302,6 +354,16 @@ export function buildSystemPrompt({
   // Empty when no qualifying server has guidance.
   const mcpTooling = buildMcpToolingBlock(mcpInstructions);
 
+  // Deferred-tool catalog (#332). Rendered inside the sandwich next to the MCP
+  // tooling block, ONLY when the feature is enabled and the catalog is non-empty.
+  // Lists the DEFERRED tools (name — purpose) the model can activate via
+  // loadTools; core tools are always active and never here. Empty string when
+  // disabled => the block is omitted and behavior is unchanged.
+  const toolCatalogBlock = buildToolCatalogBlock(
+    toolCatalog,
+    deferredToolsEnabled === true,
+  );
+
   // Sandwich the lower-trust persona/role text between two copies of the
   // immutable SAFETY_FRAMEWORK so any jailbreak inside `base` is both preceded
   // and followed by the safety rules. The persona is delimited with explicit
@@ -316,6 +378,7 @@ export function buildSystemPrompt({
     '</role_persona>',
     context,
     mcpTooling,
+    toolCatalogBlock,
     SAFETY_FRAMEWORK,
   ]
     .filter((part) => part !== '')

apps/server/src/core/ai-chat/ai-chat.role-resolve.spec.ts

@@ -53,6 +53,7 @@ describe('AiChatService.resolveRoleForRequest', () => {
       aiAgentRoleRepo as never,
       {} as never, // pageRepo
       {} as never, // pageAccess
+      {} as never, // environment
     );
     return { service, aiChatRepo, aiAgentRoleRepo };
   }

apps/server/src/core/ai-chat/ai-chat.service.lifecycle.spec.ts

@@ -22,6 +22,7 @@ describe('AiChatService.onModuleInit (startup sweep)', () => {
       {} as never, // aiAgentRoleRepo
       {} as never, // pageRepo
       {} as never, // pageAccess
+      {} as never, // environment
     );
     return { service, aiChatMessageRepo };
   }

apps/server/src/core/ai-chat/ai-chat.service.spec.ts

@@ -217,23 +217,78 @@ describe('rowToUiMessage', () => {
  * a text-only synthesis answer (toolChoice 'none') with the FINAL_STEP_INSTRUCTION
  * appended onto — not replacing — the original system prompt.
  */
+// Narrowing helpers for the prepareAgentStep union return type.
+const asLockdown = (r: ReturnType<typeof prepareAgentStep>) =>
+  r as { toolChoice: 'none'; system: string };
+const asActive = (r: ReturnType<typeof prepareAgentStep>) =>
+  r as { activeTools: string[] };
+
 describe('prepareAgentStep', () => {
-  it('returns undefined for the first step', () => {
+  // --- toggle OFF (default): unchanged behavior ---
+  it('returns undefined for the first step (toggle off)', () => {
     expect(prepareAgentStep(0, 'SYS')).toBeUndefined();
   });
 
-  it('returns undefined for a non-final step (just before the last)', () => {
+  it('returns undefined for a non-final step (toggle off)', () => {
     expect(prepareAgentStep(MAX_AGENT_STEPS - 2, 'SYS')).toBeUndefined();
   });
 
-  it('forces a text-only synthesis on the final allowed step', () => {
-    const result = prepareAgentStep(MAX_AGENT_STEPS - 1, 'SYS');
+  it('forces a text-only synthesis on the final allowed step (toggle off)', () => {
+    const result = asLockdown(prepareAgentStep(MAX_AGENT_STEPS - 1, 'SYS'));
     expect(result).toBeDefined();
-    expect(result?.toolChoice).toBe('none');
+    expect(result.toolChoice).toBe('none');
     // The original persona is preserved (prefix), not replaced.
-    expect(result?.system.startsWith('SYS')).toBe(true);
+    expect(result.system.startsWith('SYS')).toBe(true);
     // The synthesis instruction is appended.
-    expect(result?.system).toContain(FINAL_STEP_INSTRUCTION);
+    expect(result.system).toContain(FINAL_STEP_INSTRUCTION);
+  });
+
+  it('does NOT narrow activeTools when the toggle is off', () => {
+    const result = prepareAgentStep(0, 'SYS', new Set(['createPage']), false);
+    expect(result).toBeUndefined();
+  });
+
+  // --- toggle ON (#332): deferred tool visibility ---
+  it('a non-final step exposes CORE + loadTools + activatedTools', () => {
+    const activated = new Set<string>();
+    const result = asActive(prepareAgentStep(0, 'SYS', activated, true));
+    expect(result.activeTools).toContain('searchPages'); // core
+    expect(result.activeTools).toContain('searchInPage'); // #330, core
+    expect(result.activeTools).toContain('editPageText'); // core
+    expect(result.activeTools).toContain('loadTools'); // meta-tool
+    // No deferred tool is active before it is loaded.
+    expect(result.activeTools).not.toContain('createPage');
+    expect(result.activeTools).not.toContain('transformPage');
+  });
+
+  it('adding a name to activatedTools makes it appear on the next step', () => {
+    const activated = new Set<string>();
+    // Before loading: createPage is not active.
+    expect(
+      asActive(prepareAgentStep(1, 'SYS', activated, true)).activeTools,
+    ).not.toContain('createPage');
+    // loadTools grows the SAME set…
+    activated.add('createPage');
+    // …so the next step sees it.
+    const next = asActive(prepareAgentStep(2, 'SYS', activated, true));
+    expect(next.activeTools).toContain('createPage');
+    expect(next.activeTools).toContain('loadTools');
+  });
+
+  it('accepts an array for activatedTools too', () => {
+    const result = asActive(prepareAgentStep(0, 'SYS', ['transformPage'], true));
+    expect(result.activeTools).toContain('transformPage');
+    expect(result.activeTools).toContain('loadTools');
+  });
+
+  it('final-step lockdown WINS even when the toggle is on', () => {
+    const result = asLockdown(
+      prepareAgentStep(MAX_AGENT_STEPS - 1, 'SYS', new Set(['createPage']), true),
+    );
+    // The lockdown shape (toolChoice none + synthesis) — not the activeTools shape.
+    expect(result.toolChoice).toBe('none');
+    expect(result.system).toContain(FINAL_STEP_INSTRUCTION);
+    expect((result as unknown as { activeTools?: string[] }).activeTools).toBeUndefined();
   });
 });
 

apps/server/src/core/ai-chat/ai-chat.service.ts

@@ -30,7 +30,15 @@ import {
 } from '@docmost/db/types/entity.types';
 import { AiChatToolsService } from './tools/ai-chat-tools.service';
 import { McpClientsService } from './external-mcp/mcp-clients.service';
+import { EnvironmentService } from '../../integrations/environment/environment.service';
 import { buildSystemPrompt } from './ai-chat.prompt';
+import {
+  CORE_TOOL_KEYS,
+  CORE_TOOL_SET,
+  LOAD_TOOLS_NAME,
+  makeLoadToolsTool,
+  buildExternalToolCatalog,
+} from './tools/tool-tiers';
 import { computePageChange } from './page-change/page-change.util';
 import { roleModelOverride } from './roles/role-model-config';
 import {
@@ -54,24 +62,52 @@ const FINAL_STEP_INSTRUCTION =
   'language. If the information is incomplete, say so explicitly: summarize ' +
   'what you found, what is still missing, and give your best partial conclusion.';
 
-// Pure, unit-testable: decide per-step overrides. Returns undefined for normal
-// steps; on the final allowed step forces a text-only synthesis answer.
+// Pure, unit-testable: decide per-step overrides. Two responsibilities:
+//   1. Final-step lockdown (always): on the final allowed step force a text-only
+//      synthesis answer (toolChoice 'none' + FINAL_STEP_INSTRUCTION). This WINS —
+//      it takes precedence over the deferred-tool narrowing below.
+//   2. Deferred tool visibility (#332): when `deferredEnabled` and NOT the final
+//      step, expose only the CORE tools + loadTools + whatever loadTools has
+//      activated so far this turn (`activatedTools`), via `activeTools`. Deferred
+//      tools stay in the <tool_catalog> until the model loads them.
+// When `deferredEnabled` is false the behavior is unchanged: undefined on normal
+// steps (all tools active), lockdown on the final step.
+//
 // `system` is the in-scope system prompt; we CONCATENATE so the original
 // persona/context is preserved — a bare `system` override would REPLACE the
-// whole system prompt for the step.
+// whole system prompt for the step. `activatedTools` is PER-TURN mutable state
+// owned by the streaming loop (a closure Set grown by loadTools); it is passed
+// in (not module-global, not persisted) so this stays a pure function of its
+// arguments.
 //
 // NOTE: at AI SDK v7 the per-step `system` field is renamed to `instructions`.
 // On v6 (`^6.0.134`) `system` is the correct field — adjust when bumping.
 export function prepareAgentStep(
   stepNumber: number,
   system: string,
-): { toolChoice: 'none'; system: string } | undefined {
+  activatedTools: ReadonlySet<string> | readonly string[] = [],
+  deferredEnabled = false,
+):
+  | { toolChoice: 'none'; system: string }
+  | { activeTools: string[] }
+  | undefined {
+  // Final-step lockdown WINS (applies regardless of the deferred toggle).
   if (stepNumber >= MAX_AGENT_STEPS - 1) {
     return {
       toolChoice: 'none',
       system: `${system}\n\n${FINAL_STEP_INSTRUCTION}`,
     };
   }
+  // Deferred tool loading: narrow this step's visible tools to CORE + loadTools
+  // + the tools already activated this turn.
+  if (deferredEnabled) {
+    const activated = Array.isArray(activatedTools)
+      ? activatedTools
+      : [...activatedTools];
+    return {
+      activeTools: [...CORE_TOOL_KEYS, LOAD_TOOLS_NAME, ...activated],
+    };
+  }
   return undefined;
 }
 
@@ -206,6 +242,9 @@ export class AiChatService implements OnModuleInit {
     private readonly aiAgentRoleRepo: AiAgentRoleRepo,
     private readonly pageRepo: PageRepo,
     private readonly pageAccess: PageAccessService,
+    // Reads the AI_CHAT_DEFERRED_TOOLS toggle (#332). Injected last so existing
+    // positional constructor callers (tests) only append one stub.
+    private readonly environment: EnvironmentService,
   ) {}
 
   /**
@@ -625,9 +664,25 @@ export class AiChatService implements OnModuleInit {
     // Build the system prompt + Docmost toolset. If either throws after the
     // external MCP lease was taken above, release the lease before rethrowing so
     // the leased transports are not leaked (#185 review).
+    // Deferred tool loading toggle (#332). When ON, the model sees a compact
+    // <tool_catalog> and only CORE tools + loadTools are active each step; other
+    // tools (fat/rare in-app tools + ALL external MCP tools) load on demand. When
+    // OFF, every tool is active and nothing below changes.
+    const deferredEnabled = this.environment.isAiChatDeferredToolsEnabled();
+
     let system: string;
     let docmostTools: Awaited<ReturnType<AiChatToolsService['forUser']>>;
     try {
+      // Assemble the deferred catalog for the system prompt: hand-written lines
+      // for the in-app deferred tools + a derived line for each external MCP tool
+      // (also deferred by default). Only built when the feature is enabled.
+      const toolCatalog = deferredEnabled
+        ? [
+            ...(await this.tools.getInAppDeferredCatalog()),
+            ...buildExternalToolCatalog(external.tools),
+          ]
+        : [];
+
       system = buildSystemPrompt({
         workspace,
         adminPrompt: resolved?.systemPrompt,
@@ -644,6 +699,10 @@ export class AiChatService implements OnModuleInit {
         // Detected between-turns human edit to the open page (#274): adds the
         // page_changed note + unified diff so the agent doesn't overwrite it.
         pageChanged,
+        // Deferred tool loading (#332): renders the <tool_catalog> block (only
+        // when enabled + non-empty) so the model can activate deferred tools.
+        deferredToolsEnabled: deferredEnabled,
+        toolCatalog,
       });
 
       // Pass the resolved chatId so the write tools can mint provenance tokens
@@ -664,7 +723,31 @@ export class AiChatService implements OnModuleInit {
       throw err;
     }
 
-    const tools = { ...external.tools, ...docmostTools };
+    // Base toolset: external MCP tools + Docmost in-app tools (Docmost wins on a
+    // name clash — external are namespaced, so no clash is expected).
+    const baseTools = { ...external.tools, ...docmostTools };
+
+    // Deferred tool loading state (#332), scoped to THIS streaming loop:
+    //  - `activatedTools` is per-TURN mutable state — a fresh closure Set created
+    //    per streamText call, NOT module-global and NOT persisted, so a new turn
+    //    starts cold. loadTools.execute adds to it; prepareAgentStep reads it to
+    //    widen `activeTools` on the NEXT step.
+    //  - `validDeferredNames` = every tool that is NOT core (the in-app deferred
+    //    tools + ALL external MCP tools), computed from the ACTUAL toolset so an
+    //    external tool is loadable by its namespaced name. loadTools rejects any
+    //    name outside this set.
+    const activatedTools = new Set<string>();
+    const validDeferredNames = new Set<string>(
+      Object.keys(baseTools).filter((k) => !CORE_TOOL_SET.has(k)),
+    );
+    // Add the loadTools meta-tool ONLY when the feature is enabled; when off the
+    // toolset and behavior are exactly as before.
+    const tools = deferredEnabled
+      ? {
+          ...baseTools,
+          [LOAD_TOOLS_NAME]: makeLoadToolsTool(activatedTools, validDeferredNames),
+        }
+      : baseTools;
 
     // Accumulate the turn's streamed output so a provider error / disconnect can
     // persist the PARTIAL answer the user already saw — the SDK's onError/onAbort
@@ -799,7 +882,8 @@ export class AiChatService implements OnModuleInit {
         // ends with no assistant text (an empty turn). prepareAgentStep forbids
         // further tool calls and appends a synthesis instruction on that step,
         // concatenated onto the original `system` so the persona is preserved.
-        prepareStep: ({ stepNumber }) => prepareAgentStep(stepNumber, system),
+        prepareStep: ({ stepNumber }) =>
+          prepareAgentStep(stepNumber, system, activatedTools, deferredEnabled),
         abortSignal: signal,
         onChunk: ({ chunk }) => {
           // DIAGNOSTIC (Safari stream-drop investigation) — temporary. Any model

apps/server/src/core/ai-chat/tools/ai-chat-tools.service.ts

@@ -17,6 +17,10 @@ import { resolveCurrentPageResult } from './current-page.util';
 import { parseNodeArg } from './parse-node-arg';
 import { modelFriendlyInput } from './model-friendly-input';
 import { SandboxStore } from '../../../integrations/sandbox/sandbox.store';
+import {
+  buildInAppDeferredCatalog,
+  type ToolCatalogEntry,
+} from './tool-tiers';
 
 /**
  * Per-user, per-request adapter that exposes Docmost READ operations to the
@@ -123,6 +127,18 @@ export class AiChatToolsService {
     return client.exportPageMarkdown(pageId);
   }
 
+  /**
+   * Build the IN-APP deferred <tool_catalog> entries (#332): one "name — purpose"
+   * line per DEFERRED tool, merging the per-layer INLINE_TOOL_TIERS with the
+   * shared registry's own catalogLine. Loads @docmost/mcp for the shared specs
+   * (memoized). Core tools are always active and are NOT listed here. External
+   * MCP tools are catalogued separately by the caller (they are runtime-scoped).
+   */
+  async getInAppDeferredCatalog(): Promise<ToolCatalogEntry[]> {
+    const { sharedToolSpecs } = await loadDocmostMcp();
+    return buildInAppDeferredCatalog(sharedToolSpecs);
+  }
+
   async forUser(
     user: User,
     sessionId: string,
@@ -630,6 +646,16 @@ export class AiChatToolsService {
         async ({ pageId, nodeId }) => await client.getNode(pageId, nodeId),
       ),
 
+      searchInPage: sharedTool(
+        sharedToolSpecs.searchInPage,
+        async ({ pageId, query, regex, caseSensitive, limit }) =>
+          await client.searchInPage(pageId, query, {
+            regex,
+            caseSensitive,
+            limit,
+          }),
+      ),
+
       getTable: tool({
         description:
           'Read a table as a matrix of cell texts (plus a parallel cellIds ' +
@@ -649,13 +675,21 @@ export class AiChatToolsService {
 
       listComments: tool({
         description:
-          'List ALL comments on a page in one call, including RESOLVED ' +
-          'threads — filter by resolvedAt when you need only open ones. ' +
-          'Content is returned as Markdown.',
+          'List comments on a page in one call. By DEFAULT only ACTIVE ' +
+          'threads are returned; resolved threads (a resolved top-level ' +
+          'comment and all its replies) are hidden and their count reported ' +
+          'as `resolvedThreadsHidden` so you can re-query with ' +
+          '`includeResolved: true` to see everything. Returns ' +
+          '`{ items, resolvedThreadsHidden }`. Content is returned as Markdown.',
         inputSchema: modelFriendlyInput({
           pageId: z.string().describe('The id of the page.'),
+          includeResolved: z
+            .boolean()
+            .optional()
+            .describe('default only active threads; true — include resolved'),
         }),
-        execute: async ({ pageId }) => await client.listComments(pageId),
+        execute: async ({ pageId, includeResolved }) =>
+          await client.listComments(pageId, includeResolved),
       }),
 
       getComment: tool({

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
@@ -55,8 +56,18 @@ export interface DocmostClientLike {
   getOutline(pageId: string): Promise<Record<string, unknown>>;
   getPageJson(pageId: string): Promise<Record<string, unknown>>;
   getNode(pageId: string, nodeId: string): Promise<Record<string, unknown>>;
+  searchInPage(
+    pageId: string,
+    query: string,
+    opts?: { regex?: boolean; caseSensitive?: boolean; limit?: number },
+  ): Promise<Record<string, unknown>>;
   getTable(pageId: string, tableRef: string): Promise<Record<string, unknown>>;
-  listComments(pageId: string): Promise<unknown[]>;
+  // Returns `{ items, resolvedThreadsHidden }`. DEFAULT (includeResolved unset/
+  // false) hides resolved threads wholesale; pass true for the full feed.
+  listComments(
+    pageId: string,
+    includeResolved?: boolean,
+  ): Promise<{ items: unknown[]; resolvedThreadsHidden: number }>;
   getComment(
     commentId: string,
   ): Promise<{ data: Record<string, unknown>; success: boolean }>;
@@ -231,6 +242,11 @@ export interface SharedToolSpec {
   mcpName: string;
   inAppKey: string;
   description: string;
+  // Deferred-tool metadata (#332). Optional in this mirror so an older/stale
+  // @docmost/mcp build (pre-#332) still type-checks; the in-app catalog builder
+  // reads them defensively. The external /mcp server ignores both fields.
+  tier?: 'core' | 'deferred';
+  catalogLine?: string;
   // Loose `z` on purpose: the registry is zod-agnostic so the server can pass
   // its own zod (v4) and the MCP package its own (v3) into the same builder.
   buildShape?: (z: any) => Record<string, unknown>;
@@ -241,14 +257,8 @@ 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/ai-chat/tools/tool-tiers.spec.ts

@@ -0,0 +1,244 @@
+import {
+  CORE_TOOL_KEYS,
+  CORE_TOOL_SET,
+  LOAD_TOOLS_NAME,
+  LOAD_TOOLS_DESCRIPTION,
+  INLINE_TOOL_TIERS,
+  buildInAppDeferredCatalog,
+  buildExternalToolCatalog,
+  shortenForCatalog,
+  applyLoadTools,
+} from './tool-tiers';
+// The real shared registry, imported from source (same approach as the
+// SHARED_TOOL_SPECS contract spec) so the tier metadata is checked against
+// exactly what @docmost/mcp ships.
+import { SHARED_TOOL_SPECS } from '../../../../../../packages/mcp/src/tool-specs';
+// For the live-toolset partition test (F3): the REAL adapter, so the catalog is
+// checked against the tools AiChatToolsService.forUser() actually builds — not a
+// static list that could drift from it.
+import { AiChatToolsService } from './ai-chat-tools.service';
+import * as loader from './docmost-client.loader';
+import type { DocmostClientLike } from './docmost-client.loader';
+
+/**
+ * #332 deferred tool loading — tier metadata, catalog assembly, and the
+ * loadTools meta-tool. Pure units; no Nest graph, no @docmost/mcp build (the
+ * registry is imported from TS source).
+ */
+
+describe('tool tier metadata (#332)', () => {
+  it('core set is the documented 13 + searchInPage (14)', () => {
+    expect(CORE_TOOL_KEYS).toHaveLength(14);
+    expect(CORE_TOOL_SET.has('searchInPage')).toBe(true); // #330, promoted to core
+    // loadTools is a meta-tool, not a normal core key.
+    expect(CORE_TOOL_SET.has(LOAD_TOOLS_NAME)).toBe(false);
+  });
+
+  it('SHARED_TOOL_SPECS tier agrees with CORE_TOOL_SET for every shared tool', () => {
+    for (const [key, spec] of Object.entries(SHARED_TOOL_SPECS)) {
+      const isCoreByTier = spec.tier === 'core';
+      const isCoreByList = CORE_TOOL_SET.has(key);
+      expect(isCoreByTier).toBe(isCoreByList);
+      // Every spec carries a non-empty catalogLine (core tools too).
+      expect(typeof spec.catalogLine).toBe('string');
+      expect(spec.catalogLine.trim().length).toBeGreaterThan(0);
+    }
+  });
+
+  it('every INLINE tool tier agrees with CORE_TOOL_SET and has a catalogLine', () => {
+    for (const [key, meta] of Object.entries(INLINE_TOOL_TIERS)) {
+      expect(meta.tier === 'core').toBe(CORE_TOOL_SET.has(key));
+      expect(meta.catalogLine.trim().length).toBeGreaterThan(0);
+    }
+  });
+});
+
+describe('buildInAppDeferredCatalog (#332)', () => {
+  const catalog = buildInAppDeferredCatalog(SHARED_TOOL_SPECS as never);
+  const names = catalog.map((e) => e.name);
+
+  it('includes deferred tools from BOTH the inline map and the shared registry', () => {
+    expect(names).toContain('transformPage'); // inline deferred
+    expect(names).toContain('getPageJson'); // shared deferred
+    expect(names).toContain('patchNode'); // shared deferred
+    expect(names).toContain('createPage'); // inline deferred
+  });
+
+  it('NEVER lists a core tool', () => {
+    for (const core of CORE_TOOL_KEYS) {
+      expect(names).not.toContain(core);
+    }
+    // spot-check a couple that are core in each source.
+    expect(names).not.toContain('searchInPage'); // shared core
+    expect(names).not.toContain('searchPages'); // inline core
+    expect(names).not.toContain('editPageText'); // shared core
+  });
+
+  it('renders every entry as a "name — purpose" line', () => {
+    // Non-empty catalog (the length is pinned structurally by the live-toolset
+    // partition test below, not by a magic constant that rots on every new tool).
+    expect(catalog.length).toBeGreaterThan(0);
+    for (const entry of catalog) {
+      expect(entry.catalogLine).toMatch(/ — /);
+    }
+  });
+});
+
+/**
+ * F3 — the deferred <tool_catalog> is built from STATIC metadata (INLINE_TOOL_TIERS
+ * + SHARED_TOOL_SPECS), but the loadable-by-name set is derived at RUNTIME from the
+ * actual toolset (`Object.keys(baseTools)` in ai-chat.service.ts). Those two must
+ * agree or a tool becomes loadable-but-invisible (agent thinks it doesn't exist) or
+ * catalogued-but-phantom. INLINE_TOOL_TIERS is a plain hand-maintained Record with
+ * no compile-time link to the tools AiChatToolsService.forUser() builds, so nothing
+ * else catches that drift. This test uses forUser()'s LIVE keys as the source of
+ * truth (mirroring ai-chat-tools.service.spec.ts's loader mock) and asserts a
+ * two-way partition against buildInAppDeferredCatalog — replacing the old magic
+ * toHaveLength(28), so a tool added to forUser() without a catalog line (or a
+ * catalog line without a real tool) fails the suite instead of silently vanishing.
+ */
+describe('deferred catalog ↔ live forUser() toolset partition (#332, F3)', () => {
+  let toolKeys: string[];
+  const catalogNames = buildInAppDeferredCatalog(SHARED_TOOL_SPECS as never).map(
+    (e) => e.name,
+  );
+
+  beforeAll(async () => {
+    // Intercept the ESM loader so forUser() builds against the TS-source shared
+    // specs (no @docmost/mcp build) and never touches the network.
+    jest.spyOn(loader, 'loadDocmostMcp').mockResolvedValue({
+      DocmostClient: function () {
+        return {} as DocmostClientLike;
+      } as unknown as loader.DocmostClientCtor,
+      sharedToolSpecs: SHARED_TOOL_SPECS as Record<string, loader.SharedToolSpec>,
+    });
+    const service = new AiChatToolsService(
+      {
+        generateAccessToken: jest.fn().mockResolvedValue('access-token'),
+        generateCollabToken: jest.fn().mockResolvedValue('collab-token'),
+      } as never,
+      {} as never, // aiService — not exercised while merely BUILDING the tools
+      {} as never, // pageEmbeddingRepo
+      {} as never, // spaceMemberRepo
+      {} as never, // pagePermissionRepo
+      // sandboxStore: forUser() eagerly calls asSink() to wire the stash tool.
+      {
+        asSink: () => ({ put: jest.fn(), has: jest.fn(), evict: jest.fn() }),
+      } as never,
+    );
+    const tools = await service.forUser(
+      { id: 'user-1', email: 'u@example.com', workspaceId: 'ws-1' } as never,
+      'session-1',
+      'ws-1',
+      'chat-1',
+    );
+    toolKeys = Object.keys(tools);
+  });
+
+  afterAll(() => {
+    jest.restoreAllMocks();
+  });
+
+  it('exposes a non-trivial toolset (sanity: the mock actually built tools)', () => {
+    expect(toolKeys.length).toBeGreaterThan(20);
+  });
+
+  it('every non-core live tool is present in the catalog (no capability silently hidden)', () => {
+    // forUser() does not itself add loadTools (ai-chat.service does), but guard
+    // anyway. Every remaining non-core key MUST have a catalog line.
+    const catalogSet = new Set(catalogNames);
+    const missing = toolKeys.filter(
+      (k) => !CORE_TOOL_SET.has(k) && k !== LOAD_TOOLS_NAME && !catalogSet.has(k),
+    );
+    expect(missing).toEqual([]);
+  });
+
+  it('every catalog entry corresponds to a real, non-core live tool (no phantom)', () => {
+    const liveSet = new Set(toolKeys);
+    const phantom = catalogNames.filter(
+      (n) => !liveSet.has(n) || CORE_TOOL_SET.has(n),
+    );
+    expect(phantom).toEqual([]);
+  });
+});
+
+describe('buildExternalToolCatalog + shortenForCatalog (#332)', () => {
+  it('derives a short "name — purpose" line from each external tool description', () => {
+    const catalog = buildExternalToolCatalog({
+      tavily_search: { description: 'Search the web for fresh results. More detail here.' },
+      tavily_extract: { description: '' },
+    });
+    expect(catalog).toEqual([
+      { name: 'tavily_search', catalogLine: 'tavily_search — Search the web for fresh results.' },
+      { name: 'tavily_extract', catalogLine: 'tavily_extract — external tool' },
+    ]);
+  });
+
+  it('caps a very long description', () => {
+    const long = 'x'.repeat(500);
+    expect(shortenForCatalog(long).length).toBeLessThanOrEqual(140);
+    expect(shortenForCatalog(long).endsWith('…')).toBe(true);
+  });
+});
+
+describe('applyLoadTools (#332)', () => {
+  const valid = new Set(['createPage', 'transformPage', 'tavily_search']);
+
+  it('adds valid names to the activated set and returns { loaded }', () => {
+    const activated = new Set<string>();
+    const result = applyLoadTools(['createPage', 'tavily_search'], activated, valid);
+    expect(result).toEqual({ loaded: ['createPage', 'tavily_search'] });
+    expect(activated.has('createPage')).toBe(true);
+    expect(activated.has('tavily_search')).toBe(true);
+  });
+
+  it('rejects an unknown name with an error listing the valid deferred names', () => {
+    const activated = new Set<string>();
+    expect(() => applyLoadTools(['nope'], activated, valid)).toThrow(/unknown tool name/i);
+    try {
+      applyLoadTools(['nope'], activated, valid);
+    } catch (e) {
+      const msg = (e as Error).message;
+      // Lists every valid name (sorted).
+      expect(msg).toContain('createPage');
+      expect(msg).toContain('transformPage');
+      expect(msg).toContain('tavily_search');
+    }
+    // Nothing is activated on a rejected call.
+    expect(activated.size).toBe(0);
+  });
+
+  it('tolerates a non-array / empty input (loads nothing)', () => {
+    const activated = new Set<string>();
+    expect(applyLoadTools(undefined, activated, valid)).toEqual({ loaded: [] });
+    expect(applyLoadTools([], activated, valid)).toEqual({ loaded: [] });
+    expect(activated.size).toBe(0);
+  });
+
+  it('loadTools description is the verbatim issue text', () => {
+    expect(LOAD_TOOLS_DESCRIPTION).toContain('only ACTIVATES them');
+    expect(LOAD_TOOLS_DESCRIPTION).toContain('callable on your NEXT step');
+  });
+});
+
+describe('editorial "Corrector" scenario is fully served by CORE (#332)', () => {
+  it('read + comment + edit + search need no loadTools', () => {
+    // A Corrector role reads a page, searches within it, edits text, and leaves
+    // inline comments — every tool it needs is core, so it never has to load a
+    // deferred tool.
+    const needed = [
+      'getCurrentPage',
+      'getPage',
+      'searchPages',
+      'searchInPage',
+      'editPageText',
+      'createComment',
+      'listComments',
+      'getComment',
+      'resolveComment',
+    ];
+    for (const t of needed) {
+      expect(CORE_TOOL_SET.has(t)).toBe(true);
+    }
+  });
+});

apps/server/src/core/ai-chat/tools/tool-tiers.ts

@@ -0,0 +1,309 @@
+import { tool, type Tool } from 'ai';
+import { z } from 'zod';
+import type { SharedToolSpec } from './docmost-client.loader';
+
+/**
+ * Deferred tool loading for the in-app AI chat (#332).
+ *
+ * The agent otherwise sends ALL ~41 tool definitions on EVERY model call every
+ * step, bloating context. Instead we split the in-app tools into two tiers:
+ *
+ *  - CORE (hot, always active): frequent OR tiny tools whose full schema is
+ *    always visible, plus the `loadTools` meta-tool. Deferring a one-line tool is
+ *    pure loss, so tiny tools stay core even if rare.
+ *  - DEFERRED (loaded on demand): the fat/rare tools + ALL external MCP tools by
+ *    default. The model sees only a compact <tool_catalog> (name — purpose) and
+ *    calls `loadTools(names)` to ACTIVATE a tool's full schema for the NEXT step
+ *    (one extra round-trip on first use).
+ *
+ * This module is the single source of truth for the IN-APP tiering:
+ *  - CORE_TOOL_KEYS / CORE_TOOL_SET — the authoritative core list (used by
+ *    prepareAgentStep to build per-step `activeTools`).
+ *  - INLINE_TOOL_TIERS — tier + catalogLine for the per-layer INLINE tools (the
+ *    ones NOT in @docmost/mcp's SHARED_TOOL_SPECS, which carry their own).
+ *  - buildInAppDeferredCatalog / buildExternalToolCatalog — assemble the
+ *    <tool_catalog> deferred lines.
+ *  - applyLoadTools / makeLoadToolsTool — the loadTools meta-tool.
+ *
+ * The tier/catalogLine fields on SHARED_TOOL_SPECS are IN-APP metadata only; the
+ * external /mcp server ignores them and exposes every tool normally.
+ */
+
+/** A single rendered <tool_catalog> line: the tool name + its "name — purpose". */
+export interface ToolCatalogEntry {
+  /** Exact tool name the model must pass to loadTools. */
+  name: string;
+  /** Hand-written (in-app) or derived (external) "name — purpose" line. */
+  catalogLine: string;
+}
+
+/**
+ * CORE (always-active) in-app tool keys — 13 frequent/tiny tools. `searchInPage`
+ * (#330) is added to core on top of the issue's original tier list: it is
+ * frequent for the editorial roles this feature targets. `loadTools` is active
+ * too but is not a normal tool key (it is added to activeTools separately).
+ */
+export const CORE_TOOL_KEYS = [
+  'searchPages',
+  'listPages',
+  'listSpaces',
+  'getWorkspace',
+  'getCurrentPage',
+  'getPage',
+  'getOutline',
+  'getNode',
+  'createComment',
+  'getComment',
+  'listComments',
+  'resolveComment',
+  'editPageText',
+  // #330 search_in_page — frequent for editorial sweeps; core despite predating
+  // the issue's tier list.
+  'searchInPage',
+] as const;
+
+/** O(1) membership test for the core tier. */
+export const CORE_TOOL_SET: ReadonlySet<string> = new Set(CORE_TOOL_KEYS);
+
+/** The meta-tool name (always active alongside the core tools when enabled). */
+export const LOAD_TOOLS_NAME = 'loadTools';
+
+/**
+ * loadTools description — VERBATIM from issue #332. Tells the model that the
+ * catalog names EXIST, that loadTools only ACTIVATES them (callable next step),
+ * and to load several at once.
+ */
+export const LOAD_TOOLS_DESCRIPTION =
+  'loadTools — Load the full definitions of deferred tools from the <tool_catalog>\n' +
+  'block in your instructions. Pass the EXACT tool names from the catalog; this\n' +
+  'call only ACTIVATES them and returns { loaded: [...] } — the tools become\n' +
+  'callable on your NEXT step. Load several names in one call when the task clearly\n' +
+  'needs them. Unknown names are rejected with the list of valid ones.';
+
+/**
+ * Tier + catalogLine for the INLINE ai-chat tools — those defined per-layer in
+ * ai-chat-tools.service.ts and NOT present in @docmost/mcp's SHARED_TOOL_SPECS
+ * (which carries its own tier/catalogLine). Together with the shared registry
+ * this describes every in-app tool. catalogLine is present for core tools too
+ * (uniformity), but only DEFERRED tools are rendered into the catalog.
+ */
+export const INLINE_TOOL_TIERS: Record<
+  string,
+  { tier: 'core' | 'deferred'; catalogLine: string }
+> = {
+  // --- core inline ---
+  searchPages: {
+    tier: 'core',
+    catalogLine: 'searchPages — hybrid semantic + keyword search across the wiki.',
+  },
+  getCurrentPage: {
+    tier: 'core',
+    catalogLine: 'getCurrentPage — the page the user is currently viewing.',
+  },
+  getPage: {
+    tier: 'core',
+    catalogLine: 'getPage — fetch a page as Markdown by its id.',
+  },
+  listPages: {
+    tier: 'core',
+    catalogLine: "listPages — list recent pages, or a space's full page tree.",
+  },
+  listComments: {
+    tier: 'core',
+    catalogLine: 'listComments — list all comments on a page (including resolved).',
+  },
+  getComment: {
+    tier: 'core',
+    catalogLine: 'getComment — fetch a single comment by id.',
+  },
+  createComment: {
+    tier: 'core',
+    catalogLine:
+      'createComment — add an inline comment (optionally with a suggested edit).',
+  },
+  resolveComment: {
+    tier: 'core',
+    catalogLine: 'resolveComment — resolve or reopen a comment thread.',
+  },
+
+  // --- deferred inline ---
+  createPage: {
+    tier: 'deferred',
+    catalogLine: 'createPage — create a new page with a Markdown body in a space.',
+  },
+  updatePageContent: {
+    tier: 'deferred',
+    catalogLine:
+      "updatePageContent — replace a page's body (and optionally title) with new Markdown.",
+  },
+  renamePage: {
+    tier: 'deferred',
+    catalogLine: "renamePage — change a page's title only (body untouched).",
+  },
+  movePage: {
+    tier: 'deferred',
+    catalogLine: 'movePage — move a page under a new parent or to the space root.',
+  },
+  deletePage: {
+    tier: 'deferred',
+    catalogLine: 'deletePage — move a page to trash (soft delete, reversible).',
+  },
+  listSidebarPages: {
+    tier: 'deferred',
+    catalogLine:
+      "listSidebarPages — list a space's root pages or a page's direct children.",
+  },
+  getTable: {
+    tier: 'deferred',
+    catalogLine: 'getTable — read a table as a matrix of cell texts and cell ids.',
+  },
+  checkNewComments: {
+    tier: 'deferred',
+    catalogLine:
+      'checkNewComments — find comments in a space created after a timestamp.',
+  },
+  getPageHistory: {
+    tier: 'deferred',
+    catalogLine:
+      'getPageHistory — fetch one page-history version with its ProseMirror content.',
+  },
+  exportPageMarkdown: {
+    tier: 'deferred',
+    catalogLine:
+      'exportPageMarkdown — export a page to self-contained Markdown (body + comments).',
+  },
+  updatePageJson: {
+    tier: 'deferred',
+    catalogLine:
+      "updatePageJson — overwrite a page's body with a full ProseMirror document.",
+  },
+  tableInsertRow: {
+    tier: 'deferred',
+    catalogLine: 'tableInsertRow — insert a row of plain-text cells into a table.',
+  },
+  tableDeleteRow: {
+    tier: 'deferred',
+    catalogLine: 'tableDeleteRow — delete a table row at a 0-based index.',
+  },
+  tableUpdateCell: {
+    tier: 'deferred',
+    catalogLine: 'tableUpdateCell — set the text of a table cell at [row, col].',
+  },
+  sharePage: {
+    tier: 'deferred',
+    catalogLine: 'sharePage — make a page publicly accessible and return its URL.',
+  },
+  transformPage: {
+    tier: 'deferred',
+    catalogLine: "transformPage — run a sandboxed JS transform over a page's document.",
+  },
+};
+
+/**
+ * Build the <tool_catalog> deferred lines for the IN-APP tools by merging the
+ * two metadata sources: the per-layer INLINE_TOOL_TIERS and the shared registry
+ * (SHARED_TOOL_SPECS, loaded at runtime). Only DEFERRED tools are included; core
+ * tools are always active and never appear in the catalog. Pure — the caller
+ * passes the loaded specs so this stays unit-testable.
+ */
+export function buildInAppDeferredCatalog(
+  sharedToolSpecs: Record<string, SharedToolSpec>,
+): ToolCatalogEntry[] {
+  const entries: ToolCatalogEntry[] = [];
+  // Inline deferred tools (hand-written lines).
+  for (const [name, meta] of Object.entries(INLINE_TOOL_TIERS)) {
+    if (meta.tier === 'deferred') {
+      entries.push({ name, catalogLine: meta.catalogLine });
+    }
+  }
+  // Shared deferred tools (line comes from the registry's own catalogLine).
+  for (const [name, spec] of Object.entries(sharedToolSpecs)) {
+    if (spec.tier === 'deferred' && spec.catalogLine) {
+      entries.push({ name, catalogLine: spec.catalogLine });
+    }
+  }
+  return entries;
+}
+
+/**
+ * Cap an external tool's (untrusted) description into a short catalog purpose.
+ * External MCP tools have no hand-written catalogLine, so we derive one from the
+ * first sentence of the description, hard-capped. Whitespace is collapsed.
+ */
+export function shortenForCatalog(description: string, max = 140): string {
+  const flat = description.replace(/\s+/g, ' ').trim();
+  if (!flat) return 'external tool';
+  // Prefer the first sentence if it is reasonably short.
+  const firstSentence = flat.split(/(?<=[.!?])\s/)[0];
+  const base =
+    firstSentence.length > 0 && firstSentence.length <= max
+      ? firstSentence
+      : flat;
+  return base.length > max ? `${base.slice(0, max - 1).trimEnd()}…` : base;
+}
+
+/**
+ * Build catalog lines for the EXTERNAL MCP tools (all deferred by default,
+ * #332). Their names are the namespaced tool keys; the purpose is derived from
+ * each tool's own description (no hand-written line exists). Pure.
+ */
+export function buildExternalToolCatalog(
+  externalTools: Record<string, { description?: string } | undefined>,
+): ToolCatalogEntry[] {
+  return Object.entries(externalTools).map(([name, t]) => ({
+    name,
+    catalogLine: `${name} — ${shortenForCatalog(t?.description ?? '')}`,
+  }));
+}
+
+/**
+ * Pure core of the loadTools meta-tool. Validates the requested names against
+ * the per-turn set of valid deferred names, ADDS the valid ones to the caller's
+ * mutable `activatedTools` set (so they become callable next step), and returns
+ * `{ loaded }`. An unknown name throws a clear error listing the valid deferred
+ * names — surfaced to the model as a tool error so it can retry.
+ */
+export function applyLoadTools(
+  names: unknown,
+  activatedTools: Set<string>,
+  validDeferredNames: ReadonlySet<string>,
+): { loaded: string[] } {
+  const requested = Array.isArray(names)
+    ? names.filter((n): n is string => typeof n === 'string')
+    : [];
+  const unknown = requested.filter((n) => !validDeferredNames.has(n));
+  if (unknown.length > 0) {
+    const valid = [...validDeferredNames].sort().join(', ');
+    throw new Error(
+      `loadTools: unknown tool name(s): ${unknown.join(', ')}. ` +
+        `Valid deferred tools are: ${valid || '(none)'}.`,
+    );
+  }
+  for (const n of requested) activatedTools.add(n);
+  return { loaded: requested };
+}
+
+/**
+ * Build the loadTools AI-SDK tool bound to THIS turn's mutable state: the
+ * `activatedTools` set (grown by execute, read by prepareAgentStep next step)
+ * and the `validDeferredNames` set (every non-core tool in this turn's toolset,
+ * incl. external MCP). Created per streamText call — never module-global.
+ */
+export function makeLoadToolsTool(
+  activatedTools: Set<string>,
+  validDeferredNames: ReadonlySet<string>,
+): Tool {
+  return tool({
+    description: LOAD_TOOLS_DESCRIPTION,
+    inputSchema: z.object({
+      names: z
+        .array(z.string())
+        .describe(
+          'EXACT deferred tool names from the <tool_catalog> to activate for ' +
+            'your next step.',
+        ),
+    }),
+    execute: async ({ names }) =>
+      applyLoadTools(names, activatedTools, validDeferredNames),
+  });
+}

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/comment/comment.controller.spec.ts

@@ -1,4 +1,5 @@
 import {
+  BadRequestException,
   ForbiddenException,
   NotFoundException,
 } from '@nestjs/common';
@@ -117,3 +118,207 @@ describe('CommentController apply-suggestion authz', () => {
     expect(commentService.applySuggestion).not.toHaveBeenCalled();
   });
 });
+
+/**
+ * Authz-gate tests for the dismiss-suggestion route (#329). Dismissing a
+ * suggestion does NOT change the page text, so it authorizes with
+ * validateCanComment (NOT validateCanEdit) — a viewer allowed to comment but not
+ * edit can still dismiss. The gate MUST run BEFORE the service (which performs
+ * the delete/resolve + mark removal). These tests pin that boundary.
+ */
+describe('CommentController dismiss-suggestion authz', () => {
+  // isAdmin=false → ability.cannot(Manage, Settings) returns true (i.e. the user
+  // is NOT a space admin). Flip to true to model a space admin.
+  function makeController(isAdmin = false) {
+    const commentService = {
+      dismissSuggestion: jest.fn(async () => ({
+        id: 'c-1',
+        outcome: 'deleted',
+      })),
+    };
+    const commentRepo = { findById: jest.fn() };
+    const pageRepo = { findById: jest.fn() };
+    const spaceAbility = {
+      createForUser: jest.fn(async () => ({
+        cannot: jest.fn(() => !isAdmin),
+      })),
+    } as any;
+    const pageAccessService = {
+      validateCanComment: jest.fn(async () => undefined),
+      validateCanEdit: jest.fn(async () => undefined),
+    };
+    const wsService = {} as any;
+    const auditService = { log: jest.fn() };
+
+    const controller = new CommentController(
+      commentService as any,
+      commentRepo as any,
+      pageRepo as any,
+      spaceAbility,
+      pageAccessService as any,
+      wsService,
+      auditService as any,
+    );
+    return {
+      controller,
+      commentService,
+      commentRepo,
+      pageRepo,
+      pageAccessService,
+      spaceAbility,
+    };
+  }
+
+  const user: any = { id: 'u-1' };
+  const workspace: any = { id: 'ws-1' };
+  const provenance: any = undefined;
+  const dto: any = { commentId: 'c-1' };
+  // Owned by the acting user (u-1) unless a test overrides creatorId.
+  const comment = {
+    id: 'c-1',
+    pageId: 'p-1',
+    spaceId: 'sp-1',
+    creatorId: 'u-1',
+    suggestedText: 'new text',
+    selection: 'old text',
+  };
+  const page = { id: 'p-1', spaceId: 'sp-1', deletedAt: null };
+
+  it('authorizes with validateCanComment (NOT validateCanEdit) then calls the service', async () => {
+    const {
+      controller,
+      commentRepo,
+      pageRepo,
+      pageAccessService,
+      commentService,
+    } = makeController();
+    commentRepo.findById.mockResolvedValue(comment);
+    pageRepo.findById.mockResolvedValue(page);
+    const dismissed = { id: 'c-1', outcome: 'deleted' };
+    commentService.dismissSuggestion.mockResolvedValue(dismissed);
+
+    const result = await controller.dismissSuggestion(
+      dto,
+      user,
+      workspace,
+      provenance,
+    );
+
+    expect(pageAccessService.validateCanComment).toHaveBeenCalledWith(
+      page,
+      user,
+      workspace.id,
+    );
+    // Dismiss must NOT require edit access.
+    expect(pageAccessService.validateCanEdit).not.toHaveBeenCalled();
+    expect(commentService.dismissSuggestion).toHaveBeenCalledWith(
+      comment,
+      user,
+      provenance,
+    );
+    expect(result).toBe(dismissed);
+  });
+
+  it('validateCanComment throwing Forbidden rejects AND dismissSuggestion is never called', async () => {
+    const {
+      controller,
+      commentRepo,
+      pageRepo,
+      pageAccessService,
+      commentService,
+    } = makeController();
+    commentRepo.findById.mockResolvedValue(comment);
+    pageRepo.findById.mockResolvedValue(page);
+    pageAccessService.validateCanComment.mockRejectedValue(
+      new ForbiddenException('no comment access'),
+    );
+
+    await expect(
+      controller.dismissSuggestion(dto, user, workspace, provenance),
+    ).rejects.toBeInstanceOf(ForbiddenException);
+
+    expect(commentService.dismissSuggestion).not.toHaveBeenCalled();
+  });
+
+  it('missing comment: NotFound without authorizing or dismissing', async () => {
+    const { controller, commentRepo, pageRepo, pageAccessService, commentService } =
+      makeController();
+    commentRepo.findById.mockResolvedValue(null);
+
+    await expect(
+      controller.dismissSuggestion(dto, user, workspace, provenance),
+    ).rejects.toBeInstanceOf(NotFoundException);
+
+    expect(pageRepo.findById).not.toHaveBeenCalled();
+    expect(pageAccessService.validateCanComment).not.toHaveBeenCalled();
+    expect(commentService.dismissSuggestion).not.toHaveBeenCalled();
+  });
+
+  it('propagates a service BadRequest (e.g. already applied/resolved) unchanged', async () => {
+    const { controller, commentRepo, pageRepo, commentService } =
+      makeController();
+    commentRepo.findById.mockResolvedValue(comment);
+    pageRepo.findById.mockResolvedValue(page);
+    commentService.dismissSuggestion.mockRejectedValue(
+      new BadRequestException('already applied'),
+    );
+
+    await expect(
+      controller.dismissSuggestion(dto, user, workspace, provenance),
+    ).rejects.toBeInstanceOf(BadRequestException);
+  });
+
+  // --- #338 owner-or-space-admin gate (mirrors POST /comments/delete) --------
+  // A childless dismiss irreversibly hard-deletes the comment, so canComment is
+  // not enough: only the comment owner or a space admin may dismiss.
+
+  it('owner dismisses their own suggestion → allowed, no admin check needed', async () => {
+    const { controller, commentRepo, pageRepo, commentService, spaceAbility } =
+      makeController(false);
+    // comment.creatorId === user.id (owner).
+    commentRepo.findById.mockResolvedValue(comment);
+    pageRepo.findById.mockResolvedValue(page);
+
+    await controller.dismissSuggestion(dto, user, workspace, provenance);
+
+    // Owner short-circuits the admin lookup.
+    expect(spaceAbility.createForUser).not.toHaveBeenCalled();
+    expect(commentService.dismissSuggestion).toHaveBeenCalledWith(
+      comment,
+      user,
+      provenance,
+    );
+  });
+
+  it('non-owner non-admin → Forbidden AND the service is never called', async () => {
+    const { controller, commentRepo, pageRepo, commentService, spaceAbility } =
+      makeController(false); // NOT a space admin
+    commentRepo.findById.mockResolvedValue({
+      ...comment,
+      creatorId: 'someone-else',
+    });
+    pageRepo.findById.mockResolvedValue(page);
+
+    await expect(
+      controller.dismissSuggestion(dto, user, workspace, provenance),
+    ).rejects.toBeInstanceOf(ForbiddenException);
+
+    expect(spaceAbility.createForUser).toHaveBeenCalledWith(user, comment.spaceId);
+    expect(commentService.dismissSuggestion).not.toHaveBeenCalled();
+  });
+
+  it('non-owner space admin → allowed to dismiss another user’s suggestion', async () => {
+    const { controller, commentRepo, pageRepo, commentService, spaceAbility } =
+      makeController(true); // space admin
+    commentRepo.findById.mockResolvedValue({
+      ...comment,
+      creatorId: 'someone-else',
+    });
+    pageRepo.findById.mockResolvedValue(page);
+
+    await controller.dismissSuggestion(dto, user, workspace, provenance);
+
+    expect(spaceAbility.createForUser).toHaveBeenCalledWith(user, comment.spaceId);
+    expect(commentService.dismissSuggestion).toHaveBeenCalled();
+  });
+});

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

@@ -15,6 +15,7 @@ import { CreateCommentDto } from './dto/create-comment.dto';
 import { UpdateCommentDto } from './dto/update-comment.dto';
 import { ResolveCommentDto } from './dto/resolve-comment.dto';
 import { ApplySuggestionDto } from './dto/apply-suggestion.dto';
+import { DismissSuggestionDto } from './dto/dismiss-suggestion.dto';
 import { PageIdDto, CommentIdDto } from './dto/comments.input';
 import { AuthUser } from '../../common/decorators/auth-user.decorator';
 import { AuthWorkspace } from '../../common/decorators/auth-workspace.decorator';
@@ -234,6 +235,59 @@ export class CommentController {
     return this.commentService.applySuggestion(comment, user, provenance);
   }
 
+  @HttpCode(HttpStatus.OK)
+  @Post('dismiss-suggestion')
+  async dismissSuggestion(
+    @Body() dto: DismissSuggestionDto,
+    @AuthUser() user: User,
+    @AuthWorkspace() workspace: Workspace,
+    @AuthProvenance() provenance: AuthProvenanceData,
+  ) {
+    const comment = await this.commentRepo.findById(dto.commentId, {
+      includeCreator: true,
+      includeResolvedBy: true,
+    });
+    if (!comment) {
+      throw new NotFoundException('Comment not found');
+    }
+
+    const page = await this.pageRepo.findById(comment.pageId);
+    if (!page || page.deletedAt) {
+      throw new NotFoundException('Page not found');
+    }
+
+    // Authorize BEFORE revealing any structural detail (metadata-disclosure
+    // hygiene, mirroring apply-suggestion). Dismissing a suggestion does NOT
+    // change the page text — it only removes/resolves the comment — so the
+    // page-level gate is comment access (canComment), NOT edit access. A viewer
+    // allowed to comment but not edit can still dismiss their own suggestion.
+    // The structural 400s (top-level / has-a-suggested-edit / not applied /
+    // not resolved) are re-checked by the service below.
+    await this.pageAccessService.validateCanComment(page, user, workspace.id);
+
+    // AUTHZ (#338): a childless dismiss IRREVERSIBLY hard-deletes the comment,
+    // so — beyond canComment — restrict it to the comment owner OR a space
+    // admin, exactly like POST /comments/delete. canComment alone is not enough:
+    // it would let any bystander commenter erase another user's suggestion for
+    // good. (apply-suggestion deliberately stays on canEdit: accepting an edit
+    // is the editor's semantics, not the suggestion author's.)
+    const isOwner = comment.creatorId === user.id;
+    if (!isOwner) {
+      const ability = await this.spaceAbility.createForUser(
+        user,
+        comment.spaceId,
+      );
+      // Space admin can dismiss any suggestion.
+      if (ability.cannot(SpaceCaslAction.Manage, SpaceCaslSubject.Settings)) {
+        throw new ForbiddenException(
+          'You can only dismiss your own suggestions',
+        );
+      }
+    }
+
+    return this.commentService.dismissSuggestion(comment, user, provenance);
+  }
+
   @HttpCode(HttpStatus.OK)
   @Post('delete')
   async delete(@Body() input: CommentIdDto, @AuthUser() user: User, @AuthWorkspace() workspace: Workspace) {

apps/server/src/core/comment/comment.service.apply-suggestion.spec.ts

@@ -13,17 +13,27 @@ import { AuditEvent, AuditResource } from '../../common/events/audit-events';
  *
  * The collaboration gateway verdict is the pivot of the whole flow, so each test
  * pins a specific { applied, currentText } and asserts the DB persistence,
- * auto-resolve, audit, ws broadcast, and error mapping that follow from it.
+ * settle (ephemeral delete vs. resolve), audit, ws broadcast, and error mapping
+ * that follow from it.
+ *
+ * Ephemeral rule (#329): once applied a suggestion DISAPPEARS (hard-delete +
+ * strip the inline anchor mark) UNLESS the thread has replies, in which case it
+ * is resolved to preserve the discussion. `hasChildren` selects the branch.
  */
 describe('CommentService — applySuggestion', () => {
   const UPDATED = { id: 'c-1', __updated: true } as any;
 
-  function makeService(verdict: unknown) {
+  function makeService(verdict: unknown, hasChildren = false, deletedRows = 1) {
     const commentRepo: any = {
       // Both the applied-stamp re-read and resolveComment's re-read go through
       // findById; return a recognizable enriched row.
       findById: jest.fn(async () => UPDATED),
       updateComment: jest.fn(async () => undefined),
+      hasChildren: jest.fn(async () => hasChildren),
+      deleteComment: jest.fn(async () => undefined),
+      // #338 F1: the childless ephemeral delete is atomic-conditional and
+      // returns the number of rows removed (1 = deleted, 0 = a reply raced in).
+      deleteCommentIfChildless: jest.fn(async () => deletedRows),
     };
     const pageRepo: any = {};
     const wsService: any = { emitCommentEvent: jest.fn() };
@@ -74,7 +84,9 @@ describe('CommentService — applySuggestion', () => {
       .map((c: any[]) => c[0])
       .find((patch: any) => 'suggestionAppliedAt' in patch);
 
-  it('applied=true → replaces text, persists applied stamps, auto-resolves, audits, returns updated', async () => {
+  // --- no replies → ephemeral delete branch -------------------------------
+
+  it('applied=true, no replies → replaces text, hard-deletes, strips the anchor mark, audits APPLIED, outcome=deleted', async () => {
     const { service, commentRepo, wsService, collaborationGateway, auditService } =
       makeService({ applied: true, currentText: 'new text' });
 
@@ -92,37 +104,34 @@ describe('CommentService — applySuggestion', () => {
       }),
     );
 
-    // Applied stamps persisted.
-    const patch = appliedPatch(commentRepo);
-    expect(patch.suggestionAppliedAt).toBeInstanceOf(Date);
-    expect(patch.suggestionAppliedById).toBe('user-1');
+    // Ephemeral: the redundant comment is hard-deleted (atomic-conditional) and
+    // its inline anchor mark removed via the deleteCommentMark collab event.
+    expect(commentRepo.deleteCommentIfChildless).toHaveBeenCalledWith('c-1');
+    expect(collaborationGateway.handleYjsEvent).toHaveBeenCalledWith(
+      'deleteCommentMark',
+      'page.page-1',
+      expect.objectContaining({ commentId: 'c-1', user: expect.any(Object) }),
+    );
+    // No applied stamps are written for a row about to be deleted.
+    expect(appliedPatch(commentRepo)).toBeUndefined();
 
-    // Auto-resolved: resolveComment writes a resolvedAt/resolvedById patch too.
-    const resolvePatch = commentRepo.updateComment.mock.calls
-      .map((c: any[]) => c[0])
-      .find((p: any) => 'resolvedAt' in p);
-    expect(resolvePatch.resolvedAt).toBeInstanceOf(Date);
-    expect(resolvePatch.resolvedById).toBe('user-1');
-
-    // Audit + broadcast + return.
+    // Broadcast a deletion, audit the (still-applied) suggestion, report outcome.
+    expect(wsService.emitCommentEvent).toHaveBeenCalledWith(
+      'space-1',
+      'page-1',
+      expect.objectContaining({ operation: 'commentDeleted', commentId: 'c-1' }),
+    );
     expect(auditService.log).toHaveBeenCalledWith(
       expect.objectContaining({
         event: AuditEvent.COMMENT_SUGGESTION_APPLIED,
         resourceType: AuditResource.COMMENT,
         resourceId: 'c-1',
-        spaceId: 'space-1',
-        metadata: { pageId: 'page-1' },
       }),
     );
-    expect(wsService.emitCommentEvent).toHaveBeenCalledWith(
-      'space-1',
-      'page-1',
-      expect.objectContaining({ operation: 'commentUpdated', comment: UPDATED }),
-    );
-    expect(result).toBe(UPDATED);
+    expect(result.outcome).toBe('deleted');
   });
 
-  it('applied=false but currentText === suggestedText → idempotent success (no 409)', async () => {
+  it('applied=false but currentText === suggestedText, no replies → idempotent delete (no 409)', async () => {
     const { service, commentRepo, auditService } = makeService({
       applied: false,
       currentText: 'new text',
@@ -130,15 +139,55 @@ describe('CommentService — applySuggestion', () => {
 
     const result = await service.applySuggestion(suggestionComment(), user());
 
-    // The stamps are still persisted (reconciling a crash between the doc
-    // mutation and the DB write) and the call succeeds.
+    expect(commentRepo.deleteCommentIfChildless).toHaveBeenCalledWith('c-1');
+    expect(auditService.log).toHaveBeenCalledTimes(1);
+    expect(result.outcome).toBe('deleted');
+  });
+
+  // --- has replies → resolve branch (discussion preserved) ----------------
+
+  it('applied=true, WITH replies → resolves (not delete), persists applied stamps, audits, outcome=resolved', async () => {
+    const { service, commentRepo, wsService, collaborationGateway, auditService } =
+      makeService({ applied: true, currentText: 'new text' }, true);
+
+    const result = await service.applySuggestion(suggestionComment(), user());
+
+    // Applied stamps persisted.
     const patch = appliedPatch(commentRepo);
     expect(patch.suggestionAppliedAt).toBeInstanceOf(Date);
     expect(patch.suggestionAppliedById).toBe('user-1');
-    expect(auditService.log).toHaveBeenCalledTimes(1);
-    expect(result).toBe(UPDATED);
+
+    // Auto-resolved (resolveComment writes the resolve patch + resolve mark).
+    const resolvePatch = commentRepo.updateComment.mock.calls
+      .map((c: any[]) => c[0])
+      .find((p: any) => 'resolvedAt' in p);
+    expect(resolvePatch.resolvedAt).toBeInstanceOf(Date);
+    expect(resolvePatch.resolvedById).toBe('user-1');
+
+    // NOT deleted; broadcast an update, not a deletion.
+    expect(commentRepo.deleteComment).not.toHaveBeenCalled();
+    expect(collaborationGateway.handleYjsEvent).not.toHaveBeenCalledWith(
+      'deleteCommentMark',
+      expect.anything(),
+      expect.anything(),
+    );
+    expect(wsService.emitCommentEvent).toHaveBeenCalledWith(
+      'space-1',
+      'page-1',
+      expect.objectContaining({ operation: 'commentUpdated', comment: UPDATED }),
+    );
+
+    expect(auditService.log).toHaveBeenCalledWith(
+      expect.objectContaining({
+        event: AuditEvent.COMMENT_SUGGESTION_APPLIED,
+      }),
+    );
+    expect(result.id).toBe('c-1');
+    expect(result.outcome).toBe('resolved');
   });
 
+  // --- error / rejection branches -----------------------------------------
+
   it('applied=false and currentText differs → ConflictException with currentText in payload', async () => {
     const { service, commentRepo, auditService } = makeService({
       applied: false,
@@ -153,14 +202,14 @@ describe('CommentService — applySuggestion', () => {
     expect(err.getResponse()).toMatchObject({
       currentText: 'someone else edited this',
     });
-    // No persistence and no audit on a conflict.
-    expect(appliedPatch(commentRepo)).toBeUndefined();
+    // No delete and no audit on a conflict.
+    expect(commentRepo.deleteComment).not.toHaveBeenCalled();
     expect(auditService.log).not.toHaveBeenCalled();
   });
 
-  it('already-applied AND already-resolved → idempotent success, no collab call, no re-resolve (#315 double-click)', async () => {
+  it('already-applied WITH replies → idempotent success, no re-apply, resolve branch', async () => {
     const { service, collaborationGateway, commentRepo, auditService } =
-      makeService({ applied: true, currentText: 'new text' });
+      makeService({ applied: true, currentText: 'new text' }, true);
 
     const result = await service.applySuggestion(
       suggestionComment({
@@ -171,17 +220,20 @@ describe('CommentService — applySuggestion', () => {
       user(),
     );
 
-    // Idempotent SUCCESS, not a 409. The suggestion is already applied, so the
-    // collaborative document is never touched again and nothing is re-stamped
-    // or re-resolved.
-    expect(result).toBe(UPDATED);
-    expect(collaborationGateway.handleYjsEvent).not.toHaveBeenCalled();
-    expect(commentRepo.updateComment).not.toHaveBeenCalled();
-    // Same success shape as the applied path (broadcast + audit).
+    // Idempotent SUCCESS. The suggestion is already applied, so the document is
+    // never re-mutated (no applyCommentSuggestion) and nothing is re-stamped.
+    expect(collaborationGateway.handleYjsEvent).not.toHaveBeenCalledWith(
+      'applyCommentSuggestion',
+      expect.anything(),
+      expect.anything(),
+    );
+    expect(appliedPatch(commentRepo)).toBeUndefined();
+    expect(commentRepo.deleteComment).not.toHaveBeenCalled();
     expect(auditService.log).toHaveBeenCalledTimes(1);
+    expect(result.outcome).toBe('resolved');
   });
 
-  it('already-applied but NOT resolved (crash window) → idempotent success, self-heals resolve, no re-apply', async () => {
+  it('already-applied, no replies (double-click after a delete) → deletes idempotently', async () => {
     const { service, collaborationGateway, commentRepo } = makeService({
       applied: true,
       currentText: 'new text',
@@ -192,28 +244,43 @@ describe('CommentService — applySuggestion', () => {
       user(),
     );
 
-    expect(result).toBe(UPDATED);
-
-    // The suggestion is NOT re-applied to the document…
+    // No re-apply to the document; the childless applied comment is removed.
     expect(collaborationGateway.handleYjsEvent).not.toHaveBeenCalledWith(
       'applyCommentSuggestion',
       expect.anything(),
       expect.anything(),
     );
-    // …but the open thread is self-healed to resolved via resolveComment, which
-    // writes the resolve patch and updates the resolve mark.
+    expect(commentRepo.deleteCommentIfChildless).toHaveBeenCalledWith('c-1');
+    expect(result.outcome).toBe('deleted');
+  });
+
+  it('applied=true, no replies at read time but a reply races in (conditional delete → 0 rows) → resolves instead, no hard-delete, outcome=resolved (#338 F1)', async () => {
+    // The suggested text is already applied to the document, but between the
+    // hasChildren read and the atomic delete a reply landed. The parent must NOT
+    // be hard-deleted (cascade would destroy the reply); resolve the thread.
+    const { service, commentRepo, wsService, collaborationGateway } =
+      makeService({ applied: true, currentText: 'new text' }, false, 0);
+
+    const result = await service.applySuggestion(suggestionComment(), user());
+
+    expect(commentRepo.deleteCommentIfChildless).toHaveBeenCalledWith('c-1');
+    // No deletion broadcast — the row + the racing reply survive.
+    expect(wsService.emitCommentEvent).not.toHaveBeenCalledWith(
+      expect.anything(),
+      expect.anything(),
+      expect.objectContaining({ operation: 'commentDeleted' }),
+    );
+    // Fell back to resolving.
     const resolvePatch = commentRepo.updateComment.mock.calls
       .map((c: any[]) => c[0])
       .find((p: any) => 'resolvedAt' in p);
     expect(resolvePatch.resolvedAt).toBeInstanceOf(Date);
-    expect(resolvePatch.resolvedById).toBe('user-1');
     expect(collaborationGateway.handleYjsEvent).toHaveBeenCalledWith(
       'resolveCommentMark',
       'page.page-1',
       expect.objectContaining({ commentId: 'c-1', resolved: true }),
     );
-    // The applied stamps are NOT re-written (already stamped).
-    expect(appliedPatch(commentRepo)).toBeUndefined();
+    expect(result.outcome).toBe('resolved');
   });
 
   it('rejects a comment with no suggestedText', async () => {
@@ -238,8 +305,8 @@ describe('CommentService — applySuggestion', () => {
       service.applySuggestion(suggestionComment(), user()),
     ).rejects.toThrow(InternalServerErrorException);
 
-    // Nothing persisted, nothing audited.
-    expect(appliedPatch(commentRepo)).toBeUndefined();
+    // Nothing deleted, nothing audited.
+    expect(commentRepo.deleteComment).not.toHaveBeenCalled();
     expect(auditService.log).not.toHaveBeenCalled();
   });
 });

apps/server/src/core/comment/comment.service.dismiss-suggestion.spec.ts

@@ -0,0 +1,229 @@
+import { BadRequestException } from '@nestjs/common';
+import { CommentService } from './comment.service';
+import { AuditEvent, AuditResource } from '../../common/events/audit-events';
+
+/**
+ * Coverage for CommentService.dismissSuggestion (#329). Dismiss ("Не применять")
+ * removes a suggested edit WITHOUT changing the page text: the comment
+ * disappears (hard-delete + strip the inline anchor mark) unless the thread has
+ * replies, in which case it is resolved to preserve the discussion.
+ *
+ * The permission gate (canComment, NOT canEdit) lives in the controller and is
+ * covered in comment.controller.spec.ts; here we pin the service's own state
+ * guards and the delete-vs-resolve fork.
+ */
+describe('CommentService — dismissSuggestion', () => {
+  const UPDATED = { id: 'c-1', __updated: true } as any;
+
+  function makeService(hasChildren = false, deletedRows = 1) {
+    const commentRepo: any = {
+      findById: jest.fn(async () => UPDATED),
+      updateComment: jest.fn(async () => undefined),
+      hasChildren: jest.fn(async () => hasChildren),
+      deleteComment: jest.fn(async () => undefined),
+      // #338 F1: the childless ephemeral delete is now atomic-conditional and
+      // returns the number of rows removed (1 = deleted, 0 = a reply raced in).
+      deleteCommentIfChildless: jest.fn(async () => deletedRows),
+    };
+    const pageRepo: any = {};
+    const wsService: any = { emitCommentEvent: jest.fn() };
+    const collaborationGateway: any = {
+      handleYjsEvent: jest.fn(async () => undefined),
+    };
+    const generalQueue: any = { add: jest.fn(() => Promise.resolve()) };
+    const notificationQueue: any = { add: jest.fn(async () => undefined) };
+    const auditService: any = { log: jest.fn() };
+
+    const service = new CommentService(
+      commentRepo,
+      pageRepo,
+      wsService,
+      collaborationGateway,
+      generalQueue,
+      notificationQueue,
+      auditService,
+    );
+
+    return { service, commentRepo, wsService, collaborationGateway, auditService };
+  }
+
+  const suggestionComment = (over?: Partial<any>): any => ({
+    id: 'c-1',
+    pageId: 'page-1',
+    spaceId: 'space-1',
+    workspaceId: 'ws-1',
+    creatorId: 'user-1',
+    parentCommentId: null,
+    selection: 'old text',
+    suggestedText: 'new text',
+    suggestionAppliedAt: null,
+    resolvedAt: null,
+    ...over,
+  });
+  const user = (over?: Partial<any>): any => ({ id: 'user-1', ...over });
+
+  it('no replies → hard-deletes, strips the anchor mark, does NOT touch page text, audits DISMISSED, outcome=deleted', async () => {
+    const { service, commentRepo, wsService, collaborationGateway, auditService } =
+      makeService(false);
+
+    const result = await service.dismissSuggestion(suggestionComment(), user());
+
+    // Never applies the suggestion to the document.
+    expect(collaborationGateway.handleYjsEvent).not.toHaveBeenCalledWith(
+      'applyCommentSuggestion',
+      expect.anything(),
+      expect.anything(),
+    );
+    // Hard-delete (atomic-conditional) + strip mark.
+    expect(commentRepo.deleteCommentIfChildless).toHaveBeenCalledWith('c-1');
+    expect(collaborationGateway.handleYjsEvent).toHaveBeenCalledWith(
+      'deleteCommentMark',
+      'page.page-1',
+      expect.objectContaining({ commentId: 'c-1', user: expect.any(Object) }),
+    );
+    expect(wsService.emitCommentEvent).toHaveBeenCalledWith(
+      'space-1',
+      'page-1',
+      expect.objectContaining({ operation: 'commentDeleted', commentId: 'c-1' }),
+    );
+    expect(auditService.log).toHaveBeenCalledWith(
+      expect.objectContaining({
+        event: AuditEvent.COMMENT_SUGGESTION_DISMISSED,
+        resourceType: AuditResource.COMMENT,
+        resourceId: 'c-1',
+      }),
+    );
+    expect(result.outcome).toBe('deleted');
+  });
+
+  it('no replies → if the anchor-mark removal FAILS, the row is NOT deleted and the error propagates (#329: no orphan anchor)', async () => {
+    const { service, commentRepo, wsService, collaborationGateway } =
+      makeService(false);
+    // Mark removal is FATAL and runs BEFORE the irreversible row delete: a collab
+    // failure (e.g. COLLAB_DISABLE_REDIS "no live instance") must abort the whole
+    // operation, leaving row + mark consistent — never a deleted row with an
+    // orphan anchor left in the document reporting success.
+    collaborationGateway.handleYjsEvent = jest.fn(async () => {
+      throw new Error('requires a live collaboration instance');
+    });
+
+    await expect(
+      service.dismissSuggestion(suggestionComment(), user()),
+    ).rejects.toThrow(/live collaboration/);
+
+    expect(commentRepo.deleteCommentIfChildless).not.toHaveBeenCalled();
+    expect(wsService.emitCommentEvent).not.toHaveBeenCalledWith(
+      expect.anything(),
+      expect.anything(),
+      expect.objectContaining({ operation: 'commentDeleted' }),
+    );
+  });
+
+  it('WITH replies → resolves (not delete), does NOT apply, audits DISMISSED, outcome=resolved', async () => {
+    const { service, commentRepo, wsService, collaborationGateway, auditService } =
+      makeService(true);
+
+    const result = await service.dismissSuggestion(suggestionComment(), user());
+
+    // Resolved via resolveComment (resolve patch + resolve mark), NOT deleted.
+    const resolvePatch = commentRepo.updateComment.mock.calls
+      .map((c: any[]) => c[0])
+      .find((p: any) => 'resolvedAt' in p);
+    expect(resolvePatch.resolvedAt).toBeInstanceOf(Date);
+    expect(resolvePatch.resolvedById).toBe('user-1');
+    expect(commentRepo.deleteComment).not.toHaveBeenCalled();
+    expect(collaborationGateway.handleYjsEvent).toHaveBeenCalledWith(
+      'resolveCommentMark',
+      'page.page-1',
+      expect.objectContaining({ commentId: 'c-1', resolved: true }),
+    );
+    // No applied stamp — dismiss does not apply the edit.
+    const appliedPatch = commentRepo.updateComment.mock.calls
+      .map((c: any[]) => c[0])
+      .find((p: any) => 'suggestionAppliedAt' in p);
+    expect(appliedPatch).toBeUndefined();
+
+    expect(auditService.log).toHaveBeenCalledWith(
+      expect.objectContaining({
+        event: AuditEvent.COMMENT_SUGGESTION_DISMISSED,
+      }),
+    );
+    expect(result.outcome).toBe('resolved');
+  });
+
+  it('reply races in after the childless read (conditional delete → 0 rows) → resolves instead, does NOT hard-delete, reply survives, outcome=resolved (#338 F1)', async () => {
+    // hasChildren=false selects the ephemeral branch (the read saw no replies),
+    // but the atomic delete matches 0 rows because a reply landed in the window
+    // between that read and the delete. The parent must NOT be hard-deleted
+    // (a cascade would destroy the just-added reply); the thread is resolved.
+    const { service, commentRepo, wsService, collaborationGateway } =
+      makeService(false, 0);
+
+    const result = await service.dismissSuggestion(suggestionComment(), user());
+
+    // The conditional delete was attempted (and matched nothing).
+    expect(commentRepo.deleteCommentIfChildless).toHaveBeenCalledWith('c-1');
+    // No commentDeleted broadcast — the row (and the racing reply) survive.
+    expect(wsService.emitCommentEvent).not.toHaveBeenCalledWith(
+      expect.anything(),
+      expect.anything(),
+      expect.objectContaining({ operation: 'commentDeleted' }),
+    );
+    // Fell back to resolving the thread.
+    const resolvePatch = commentRepo.updateComment.mock.calls
+      .map((c: any[]) => c[0])
+      .find((p: any) => 'resolvedAt' in p);
+    expect(resolvePatch.resolvedAt).toBeInstanceOf(Date);
+    expect(resolvePatch.resolvedById).toBe('user-1');
+    expect(collaborationGateway.handleYjsEvent).toHaveBeenCalledWith(
+      'resolveCommentMark',
+      'page.page-1',
+      expect.objectContaining({ commentId: 'c-1', resolved: true }),
+    );
+    expect(result.outcome).toBe('resolved');
+  });
+
+  it('rejects a reply (non-top-level) comment', async () => {
+    const { service, commentRepo } = makeService();
+    await expect(
+      service.dismissSuggestion(
+        suggestionComment({ parentCommentId: 'parent-1' }),
+        user(),
+      ),
+    ).rejects.toThrow(BadRequestException);
+    expect(commentRepo.deleteComment).not.toHaveBeenCalled();
+  });
+
+  it('rejects a comment without a suggested edit', async () => {
+    const { service, commentRepo } = makeService();
+    await expect(
+      service.dismissSuggestion(
+        suggestionComment({ suggestedText: null }),
+        user(),
+      ),
+    ).rejects.toThrow(BadRequestException);
+    expect(commentRepo.deleteComment).not.toHaveBeenCalled();
+  });
+
+  it('rejects an already-applied suggestion', async () => {
+    const { service, commentRepo } = makeService();
+    await expect(
+      service.dismissSuggestion(
+        suggestionComment({ suggestionAppliedAt: new Date() }),
+        user(),
+      ),
+    ).rejects.toThrow(BadRequestException);
+    expect(commentRepo.deleteComment).not.toHaveBeenCalled();
+  });
+
+  it('rejects an already-resolved thread', async () => {
+    const { service, commentRepo } = makeService();
+    await expect(
+      service.dismissSuggestion(
+        suggestionComment({ resolvedAt: new Date() }),
+        user(),
+      ),
+    ).rejects.toThrow(BadRequestException);
+    expect(commentRepo.deleteComment).not.toHaveBeenCalled();
+  });
+});

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

@@ -35,6 +35,12 @@ import {
   IAuditService,
 } from '../../integrations/audit/audit.service';
 
+// Ephemeral-suggestion settle result (#329): 'deleted' → the comment vanished
+// (hard-delete + anchor mark stripped); 'resolved' → the thread had replies and
+// was resolved instead. Returned to the client so it can pick the optimistic
+// cache action.
+export type SuggestionOutcome = 'deleted' | 'resolved';
+
 @Injectable()
 export class CommentService {
   private readonly logger = new Logger(CommentService.name);
@@ -362,7 +368,7 @@ export class CommentService {
     comment: Comment,
     user: User,
     provenance?: AuthProvenanceData,
-  ): Promise<Comment> {
+  ): Promise<Comment & { outcome: SuggestionOutcome }> {
     // Structural guards.
     if (comment.parentCommentId) {
       throw new BadRequestException(
@@ -449,42 +455,148 @@ export class CommentService {
   }
 
   /**
-   * Persist the applied stamps (idempotently), auto-resolve the thread and
-   * broadcast + audit the applied suggestion. Shared by the applied and the
+   * Dismiss ("Не применять") a suggested edit without touching the page text:
+   * the suggestion disappears. Ephemeral rule (#329) — a top-level suggestion
+   * comment is transient UI, so dismissing it hard-deletes the comment AND strips
+   * its inline anchor mark UNLESS the thread has replies, in which case the
+   * discussion is preserved by resolving it instead.
+   *
+   * Dismiss does NOT change the document text, so the controller authorizes it
+   * with canComment (NOT canEdit). This re-checks the comment's own state so the
+   * invariant holds regardless of caller.
+   */
+  async dismissSuggestion(
+    comment: Comment,
+    user: User,
+    provenance?: AuthProvenanceData,
+  ): Promise<Comment & { outcome: SuggestionOutcome }> {
+    // Structural guards (mirror applySuggestion).
+    if (comment.parentCommentId) {
+      throw new BadRequestException(
+        'Only a top-level comment can carry a suggested edit',
+      );
+    }
+    if (!comment.suggestedText) {
+      throw new BadRequestException(
+        'This comment has no suggested edit to dismiss',
+      );
+    }
+    // State guards: dismissing an already-applied or already-resolved thread is
+    // meaningless. On an apply↔dismiss race the loser sees the comment already
+    // gone (404 at the controller) or already resolved (this 400); the client
+    // treats both as "already resolved".
+    if (comment.suggestionAppliedAt) {
+      throw new BadRequestException(
+        'Cannot dismiss a suggested edit that was already applied',
+      );
+    }
+    if (comment.resolvedAt) {
+      throw new BadRequestException(
+        'Cannot dismiss a suggested edit on a resolved comment thread',
+      );
+    }
+
+    const hasChildren = await this.commentRepo.hasChildren(comment.id);
+
+    if (hasChildren) {
+      // Preserve the discussion: resolve (never delete) a thread with replies.
+      const updatedComment = await this.resolveComment(
+        comment,
+        true,
+        user,
+        provenance,
+      );
+      this.auditService.log({
+        event: AuditEvent.COMMENT_SUGGESTION_DISMISSED,
+        resourceType: AuditResource.COMMENT,
+        resourceId: comment.id,
+        spaceId: comment.spaceId,
+        metadata: { pageId: comment.pageId },
+      });
+      return { ...updatedComment, outcome: 'resolved' };
+    }
+
+    // Ephemeral: no replies → the suggestion vanishes entirely. The atomic
+    // conditional delete may still fall back to a resolve if a reply raced in
+    // (see deleteEphemeralSuggestion), so the outcome is whatever it settled on.
+    const settled = await this.deleteEphemeralSuggestion(comment, user, provenance);
+    this.auditService.log({
+      event: AuditEvent.COMMENT_SUGGESTION_DISMISSED,
+      resourceType: AuditResource.COMMENT,
+      resourceId: comment.id,
+      spaceId: comment.spaceId,
+      metadata: { pageId: comment.pageId },
+    });
+    return settled;
+  }
+
+  /**
+   * Persist the applied stamps (idempotently), then settle the suggestion under
+   * the ephemeral rule (#329): a suggestion whose thread has NO replies
+   * DISAPPEARS after apply (hard-delete + strip the inline anchor mark), since
+   * the suggested text is now in the document and a stand-alone resolved thread
+   * would only pile up an orphan anchor. A thread WITH replies is preserved by
+   * auto-resolving it (the historical behaviour). Shared by the applied and the
    * idempotent "already-applied" branches of applySuggestion.
+   *
+   * Returns the comment augmented with `outcome` so the client can pick the
+   * optimistic action ('deleted' → drop it, 'resolved' → move to the resolved
+   * tab).
    */
   private async finalizeAppliedSuggestion(
     comment: Comment,
     user: User,
     provenance?: AuthProvenanceData,
-  ): Promise<Comment> {
-    if (!comment.suggestionAppliedAt) {
-      await this.commentRepo.updateComment(
-        {
-          suggestionAppliedAt: new Date(),
-          suggestionAppliedById: user.id,
-        },
-        comment.id,
-      );
+  ): Promise<Comment & { outcome: SuggestionOutcome }> {
+    const hasChildren = await this.commentRepo.hasChildren(comment.id);
+
+    if (hasChildren) {
+      // Thread has replies → preserve the discussion: stamp applied + resolve.
+      if (!comment.suggestionAppliedAt) {
+        await this.commentRepo.updateComment(
+          {
+            suggestionAppliedAt: new Date(),
+            suggestionAppliedById: user.id,
+          },
+          comment.id,
+        );
+      }
+
+      // Auto-resolve the thread. resolveComment handles the resolve mark, its ws
+      // broadcast and the resolve notification. Stay defensive on re-entry.
+      if (!comment.resolvedAt) {
+        await this.resolveComment(comment, true, user, provenance);
+      }
+
+      const updatedComment = await this.commentRepo.findById(comment.id, {
+        includeCreator: true,
+        includeResolvedBy: true,
+      });
+
+      this.wsService.emitCommentEvent(comment.spaceId, comment.pageId, {
+        operation: 'commentUpdated',
+        pageId: comment.pageId,
+        comment: updatedComment,
+      });
+
+      this.auditService.log({
+        event: AuditEvent.COMMENT_SUGGESTION_APPLIED,
+        resourceType: AuditResource.COMMENT,
+        resourceId: comment.id,
+        spaceId: comment.spaceId,
+        metadata: { pageId: comment.pageId },
+      });
+
+      return { ...updatedComment, outcome: 'resolved' };
     }
 
-    // Auto-resolve the thread. resolveComment handles the resolve mark, its ws
-    // broadcast and the resolve notification. The guard above guarantees the
-    // thread was open when we entered, but stay defensive on re-entry.
-    if (!comment.resolvedAt) {
-      await this.resolveComment(comment, true, user, provenance);
-    }
-
-    const updatedComment = await this.commentRepo.findById(comment.id, {
-      includeCreator: true,
-      includeResolvedBy: true,
-    });
-
-    this.wsService.emitCommentEvent(comment.spaceId, comment.pageId, {
-      operation: 'commentUpdated',
-      pageId: comment.pageId,
-      comment: updatedComment,
-    });
+    // No replies → ephemeral: the suggested text is already in the document, so
+    // the comment is redundant. Hard-delete it and strip its inline anchor. We
+    // deliberately do NOT write the applied stamps first (the row is about to be
+    // deleted); the audit event still records that the suggestion was applied.
+    // The delete is atomic-conditional: if a reply raced in after the
+    // hasChildren read, it falls back to resolving instead (outcome 'resolved').
+    const settled = await this.deleteEphemeralSuggestion(comment, user, provenance);
 
     this.auditService.log({
       event: AuditEvent.COMMENT_SUGGESTION_APPLIED,
@@ -494,7 +606,86 @@ export class CommentService {
       metadata: { pageId: comment.pageId },
     });
 
-    return updatedComment;
+    return settled;
+  }
+
+  /**
+   * Settle an ephemeral suggestion whose thread looked childless: remove its
+   * inline `comment` anchor mark, then ATOMICALLY hard-delete the row only if it
+   * is still childless. Shared by the apply/dismiss no-replies branches (#329).
+   *
+   * ORDER MATTERS: the anchor mark is removed FIRST and FATALLY (mirrors
+   * applySuggestion, which mutates the doc before writing the DB). The row
+   * delete is irreversible, so if the mark removal fails — including the
+   * COLLAB_DISABLE_REDIS "no live instance" hard-error — we must NOT delete the
+   * row and report success, or the document is left with a permanent orphan
+   * anchor pointing at a comment that no longer exists (the exact data-integrity
+   * bug #329 targets). Let the exception propagate (→ 5xx); the operation is
+   * then repeatable with row + mark still consistent.
+   *
+   * RACE (#338 F4): the caller read `hasChildren` BEFORE the (slow) mark
+   * removal, so a reply can land in that window. `comments.parent_comment_id` is
+   * ON DELETE CASCADE, so an unconditional delete here would cascade-destroy the
+   * just-added reply forever. Instead we use `deleteCommentIfChildless`, which
+   * re-checks childlessness under a FOR UPDATE lock inside a transaction (a plain
+   * anti-join DELETE is NOT race-safe under READ COMMITTED — see the repo method
+   * docstring). If it removes the row (outcome 'deleted') we broadcast the
+   * deletion as before. If it removes 0 rows (a reply interleaved) we do NOT
+   * hard-delete — we resolve the thread instead (outcome 'resolved'), preserving
+   * the discussion and the new reply. The anchor mark is already gone by then, an
+   * accepted degradation: the thread lands in the resolved tab without its inline
+   * highlight — far better than losing a reply.
+   */
+  private async deleteEphemeralSuggestion(
+    comment: Comment,
+    user: User,
+    provenance?: AuthProvenanceData,
+  ): Promise<Comment & { outcome: SuggestionOutcome }> {
+    await this.deleteCommentMark(comment, user);
+
+    const deletedRows = await this.commentRepo.deleteCommentIfChildless(
+      comment.id,
+    );
+
+    if (deletedRows > 0) {
+      this.wsService.emitCommentEvent(comment.spaceId, comment.pageId, {
+        operation: 'commentDeleted',
+        pageId: comment.pageId,
+        commentId: comment.id,
+      });
+      return { ...comment, outcome: 'deleted' };
+    }
+
+    // A reply interleaved between the hasChildren read and this delete, so the
+    // conditional delete matched nothing. Preserve the discussion + the new
+    // reply by resolving the thread instead of hard-deleting it. resolveComment
+    // handles the resolve patch, its ws broadcast and the resolve notification;
+    // its collab call is best-effort, so the already-stripped mark is fine.
+    const resolvedComment = await this.resolveComment(
+      comment,
+      true,
+      user,
+      provenance,
+    );
+    return { ...resolvedComment, outcome: 'resolved' };
+  }
+
+  /**
+   * Remove the inline `comment` mark for a comment from the collaborative
+   * document. FATAL, NOT best-effort: unlike resolveComment (which keeps the row,
+   * so a failed mark update is recoverable), this is used before an irreversible
+   * hard-delete, so the mark removal MUST succeed or throw. Under
+   * COLLAB_DISABLE_REDIS the gateway invokes the deleteCommentMark handler
+   * directly (never a silent no-op) and a missing live instance surfaces as a
+   * thrown error, which we let propagate so the caller aborts before deleting.
+   */
+  private async deleteCommentMark(comment: Comment, user: User): Promise<void> {
+    const documentName = `page.${comment.pageId}`;
+    await this.collaborationGateway.handleYjsEvent(
+      'deleteCommentMark',
+      documentName,
+      { commentId: comment.id, user },
+    );
   }
 
   private async queueCommentNotification(

apps/server/src/core/comment/dto/dismiss-suggestion.dto.ts

@@ -0,0 +1,6 @@
+import { IsUUID } from 'class-validator';
+
+export class DismissSuggestionDto {
+  @IsUUID()
+  commentId: string;
+}

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

@@ -948,6 +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 {
@@ -1017,6 +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(
@@ -1289,8 +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(

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/comment/comment.repo.ts

@@ -139,6 +139,65 @@ export class CommentRepo {
     await this.db.deleteFrom('comments').where('id', '=', commentId).execute();
   }
 
+  /**
+   * Delete an ephemeral suggestion row ONLY if it is still childless, returning
+   * the number of rows removed (0 or 1). Closes the data-loss race in
+   * dismiss/apply (#338 F4): the service reads `hasChildren`, then removes the
+   * anchor mark (a collab round-trip of tens-to-hundreds of ms), then calls this.
+   * `comments.parent_comment_id` is ON DELETE CASCADE, so a reply landing in that
+   * window would be cascade-destroyed by a blind delete.
+   *
+   * A single anti-join `DELETE … WHERE NOT EXISTS(child)` is NOT sufficient under
+   * READ COMMITTED: if a reply INSERT (holding FOR KEY SHARE on the parent, not
+   * yet committed) interleaves, the DELETE's snapshot does not see the
+   * uncommitted child, so `NOT EXISTS` is true and the parent qualifies; the
+   * DELETE then blocks on the child's key-share lock, and when it wakes the row
+   * was only LOCKED (not modified), so EvalPlanQual does NOT re-evaluate the
+   * predicate → the parent is deleted and the just-committed reply cascades away.
+   *
+   * So we do a lock-then-recheck in ONE transaction:
+   *  1. `SELECT id … FOR UPDATE` on the parent. FOR UPDATE conflicts with the
+   *     FOR KEY SHARE a concurrent reply INSERT takes on its parent (FK), so a
+   *     reply in the window serializes against us: it either commits before we
+   *     acquire the lock, or it must wait until this tx ends.
+   *  2. Re-read childlessness with a FRESH statement in the SAME tx. Under RC a
+   *     new statement gets a new snapshot, so a reply that committed while we
+   *     waited on the lock is now visible.
+   *  3. Delete only if still childless (return 1); otherwise return 0 so the
+   *     caller resolves the thread instead. The FOR UPDATE lock is held to
+   *     end-of-tx, so no new reply can insert between the re-check and the delete.
+   */
+  async deleteCommentIfChildless(commentId: string): Promise<number> {
+    return this.db.transaction().execute(async (trx) => {
+      const parent = await trx
+        .selectFrom('comments')
+        .select('id')
+        .where('id', '=', commentId)
+        .forUpdate()
+        .executeTakeFirst();
+
+      // Already gone (e.g. a racing delete won) → nothing to remove.
+      if (!parent) return 0;
+
+      const child = await trx
+        .selectFrom('comments')
+        .select('id')
+        .where('parentCommentId', '=', commentId)
+        .limit(1)
+        .executeTakeFirst();
+
+      // A reply exists (possibly one that just committed) → do NOT hard-delete;
+      // the cascade would destroy it. Caller falls back to resolving the thread.
+      if (child) return 0;
+
+      await trx
+        .deleteFrom('comments')
+        .where('id', '=', commentId)
+        .execute();
+      return 1;
+    });
+  }
+
   async hasChildren(commentId: string): Promise<boolean> {
     const result = await this.db
       .selectFrom('comments')

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

@@ -349,6 +349,11 @@ 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();
 
@@ -399,6 +404,7 @@ export class PageRepo {
           .set({
             deletedById: deletedById,
             deletedAt: currentDate,
+            ...(lastUpdatedSource ? { lastUpdatedSource } : {}),
           })
           .where('id', 'in', pageIds)
           .where('deletedAt', 'is', null)
@@ -429,7 +435,14 @@ 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')
@@ -480,7 +493,12 @@ 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

@@ -15,6 +15,164 @@ describe('EnvironmentService', () => {
     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);
+    });
+  });
+
   describe('getSandboxTtlMs', () => {
     // ConfigService stub: get(key, def) returns the configured value for the key
     // (falling back to def), matching the @nestjs/config contract the service

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

@@ -261,6 +261,21 @@ export class EnvironmentService {
     return disable === 'true';
   }
 
+  /**
+   * Deferred tool loading for the in-app AI chat (#332). When enabled, the agent
+   * sees a compact <tool_catalog> and only CORE tools + the loadTools meta-tool
+   * are active each step; deferred tools (the fat/rare ones + all external MCP
+   * tools) load on demand. Defaults to ENABLED — the issue treats deferred
+   * loading as the new behavior; set AI_CHAT_DEFERRED_TOOLS=false to restore the
+   * old "all tools always active" behavior.
+   */
+  isAiChatDeferredToolsEnabled(): boolean {
+    const enabled = this.configService
+      .get<string>('AI_CHAT_DEFERRED_TOOLS', 'true')
+      .toLowerCase();
+    return enabled === 'true';
+  }
+
   getPostHogHost(): string {
     return this.configService.get<string>('POSTHOG_HOST');
   }
@@ -339,6 +354,99 @@ export class EnvironmentService {
       .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');
+  }
+
   // --- Blob sandbox (in-RAM ephemeral blob transfer; see SandboxModule) ---
 
   // Base URL the sandbox `uri` is built from. It MUST be reachable over the

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

@@ -172,6 +172,55 @@ 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;
+
   // --- Blob sandbox (in-RAM ephemeral blob transfer; see SandboxModule) ---
 
   @IsOptional()

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 +1,57 @@
+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,
+  sanitizeTitle as sanitizeTitleFn,
+  docsCanonicallyEqual as docsCanonicallyEqualFn,
+} 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;
+  sanitizeTitle: typeof sanitizeTitleFn;
+  docsCanonicallyEqual: typeof docsCanonicallyEqualFn;
+}
+
+// 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;
+}