docs(deploy): поправить устаревший коммент про auto-reload скрытой вкладки под вариант C (#481, ревью F1)

r1-коммент утверждал «auto-reload on a hidden tab», но вариант C (r2) убрал
авто-reload скрытой вкладки ради защиты несохранённого ввода. Переписал под
фактическое поведение: баннер + отложенный reload на следующей in-app навигации.

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

AGENTS.md

@@ -5,6 +5,139 @@ repository. It has two layers: **how to run a task end-to-end** (the
 sections below), and **how the codebase is built** (the technical sections
 further down, formerly in `CLAUDE.md`).
 
+## ARCHITECTURAL INVARIANTS — NON-NEGOTIABLE
+
+THE TEN RULES BELOW ARE HARD CONSTRAINTS. Each one was paid for with a real
+production incident or a multi-PR bug chain in THIS repository (cited inline).
+They override convenience, deadlines and "it's just a small feature". A PR that
+violates any of them MUST be rejected in review regardless of how good the rest
+of it is. If a task genuinely seems to require breaking one — STOP and raise it
+with the owner; do not code around it.
+
+### 1. EVERY BUFFER, CACHE, HISTORY AND PAYLOAD HAS AN EXPLICIT SIZE BUDGET
+
+Nothing accumulates unboundedly. A row/item cap is NOT a byte cap. Anything
+replayed to a model, buffered in memory, persisted per step, or refetched by a
+poll must state its budget in bytes/tokens and enforce it. Rewriting a growing
+structure in full on every increment is FORBIDDEN — append or diff instead;
+O(n²) write/serialize patterns do not pass review.
+(Paid for by: full-row rewrite on every agent step — hundreds of MB of Postgres
+writes per 50-step run, with every tool output serialized twice; unbounded
+history replay killing long chats on the provider context window; 32 MB replay
+buffers per active run.)
+
+### 2. EVERYTHING LONG-RUNNING TERMINATES BY CONSTRUCTION
+
+Every run / row / session / lease / subscriber / queue entry must define AT
+DESIGN TIME: its owner; every terminal state; who writes the terminal state on
+EVERY path (success, error, abort, disconnect in each phase, process restart);
+retries for the terminal write; and a periodic sweeper that does not depend on
+a reboot. A best-effort terminal write with no retry and no sweep is FORBIDDEN.
+(Paid for by: assistant rows stuck 'streaming' forever; runs stuck 'running'
+409-locking their chat until a restart — the #183/#184 follow-up chain.)
+
+### 3. EVERY AWAIT IS CANCELLABLE AND DEADLINED; NEVER BLOCK THE EVENT LOOP
+
+Every async step inside a request or agent turn honors the turn's AbortSignal
+AND a wall-clock deadline — including in-app tools, lock queues and pagination
+loops, not just external calls. Synchronous CPU work beyond ~50 ms goes to a
+worker_thread. Promise.race DOES NOT cancel synchronous work — using it as a
+"timeout" for sync computation is forbidden (the timer only fires after the
+event loop is free again, i.e. after the damage is done).
+(Paid for by: in-app tools ignoring abortSignal and writing pages AFTER Stop;
+the synchronous ELK layout freezing every SSE stream in the process; the
+step-0 MCP handshake hang — #397.)
+
+### 4. ONE SOURCE OF TRUTH; EVERYTHING ELSE IS A REBUILDABLE CACHE
+
+Postgres is the authoritative state. Every in-memory structure (registries,
+caches, client stores) must be reconstructible from the DB and treated as
+lossy. The client renders SERVER-DECLARED state — "a run is active" is a server
+fact delivered as data, never inferred from side signals (204 vs 2xx, the
+flavor of a disconnect). A new feature must name the owner of each piece of
+state before implementation starts.
+(Paid for by: the strip/restore resume machinery, silently frozen UIs and
+ghost sends after unmount — the #381→#432→#456 chain.)
+
+### 5. STATE MACHINES ARE EXPLICIT — ONE-SHOT FLAGS ARE FORBIDDEN
+
+A complex lifecycle (chat thread, resume/reconnect, run) lives in a named-state
+automaton (reducer / enum) where every state has an owner and a rendered
+representation — including the failure states. Adding a boolean ref that one
+callback arms and another reads-and-clears is FORBIDDEN in the AI-chat client.
+New behavior = a new named state + explicit transitions, and the interruption
+matrix (disconnect in each phase × restart × stop × supersede) is enumerated at
+design time, not discovered one incident at a time.
+(Paid for by: 26 one-shot useRef flags in chat-thread.tsx and the drip of
+"one more missing transition" across #381→#386/#389→#432→#456.)
+
+### 6. NO NEW MODE FORKS; A FLAG IS FOR ROLLOUT, THEN IT DIES
+
+A behavior flag that forks a code path must ship with a written sunset
+condition; stacking a new flag onto the existing matrix without deleting or
+scheduling an old one is forbidden. While a temporary fork exists, BOTH sides
+must share identical lifecycle handling (abort semantics, error listeners,
+concurrency gates) — asymmetric forks are outlawed.
+(Paid for by: legacy vs autonomous divergence — the one-active-run gate and
+the socket 'error' listener each existing on only ONE side; 2^4 flag
+combinations each with different abort semantics.)
+
+### 7. NO HAND-SYNCED MIRRORS — CODEGEN OR A CI PARITY TEST, NOTHING LESS
+
+Two copies of the same knowledge (schema, tool registry, glyph map, probe
+body, hash/normalize algorithm, label list) require either generation from a
+single source or a CI test that FAILS on drift. A "mirror this change over
+there" comment is NOT a guard and does not pass review.
+(Paid for by: #293 — three drifting converter copies losing data; #447 —
+REGISTRY_STAMP covering only one of the mirrored files; ~10 still-unguarded
+mirrors across the MCP layer.)
+
+### 8. CACHES, HEADERS, BUFFERS AND FSM TRANSITIONS GET AN INTEGRATION TEST OF THE OBSERVABLE PROPERTY
+
+A unit test of a pure helper DOES NOT COUNT for these. Test the real header on
+the real HTTP response, the real cache hit under real token sources, the real
+transition under a really-killed socket. If the observable property cannot be
+tested, the design is wrong — fix the design, not the test.
+(Paid for by: #431→#439 — a cache keyed on a fresh-per-call JWT, so it NEVER
+hit and became prod incident #435 while its unit tests stayed green; and by
+the #352→#455 immutable-cache header silently overwritten by a framework
+default AFTER the unit-tested code ran.)
+
+### 9. CLIENT INPUT IS HOSTILE UNTIL VALIDATED — ALSO BEFORE PERSISTENCE
+
+Anything from the browser (message parts, ids, titles, selections, flags) is
+validated/sanitized BEFORE it is persisted into a row that will later be
+replayed into a prompt, a converter or another subsystem. A poisoned row must
+never be able to permanently brick a chat or a page on every subsequent read.
+(Paid for by: unvalidated UIMessage parts persisted verbatim — one bad row
+500s the chat on every later turn; #159 client-spoofed page titles; #388
+selection re-sanitized server-side for the same reason.)
+
+### 10. FAILURES ARE LOUD AND SPECIFIC; SILENT DEGRADATION IS FORBIDDEN
+
+Extends the error convention below: a fire-and-forget write is allowed ONLY
+with a metric or a greppable ERROR log; a degraded mode (dead cached MCP
+client, stopped poll, exhausted retries, evicted buffer) must be VISIBLE to
+the user or the operator. A feature that can quietly stop working — a frozen
+"streaming…" UI, a poll that silently gives up, a cache serving corpses — does
+not pass review.
+(Paid for by: the degraded poll's silent 10-minute death leaving a forever-
+"streaming" answer; dead MCP clients served from cache while every external
+tool call failed; #435 being caught in minutes ONLY because metrics — #403 —
+existed.)
+
+## Default skill for feature design
+
+For any feature-design request — the user hands over a raw feature idea, asks
+to design or think through a feature, or to draft an issue («спроектируй»,
+«продумай фичу», «составь ишью», "design X", "write an issue for X") — invoke
+the `orchestrator-feature-designer` skill (Skill tool) BEFORE any other work.
+It is the default operating mode for design work in this repository: research
+→ design checklist (R1–R10) → forks resolved with the human → adversarial
+self-attack → filed PR-sized issues. Do not design features or write issues
+ad-hoc while this skill is available. This does not apply to non-design work
+(bug fixes, reviews, retrospectives, refactors already specified by an issue).
+
 ## Task lifecycle
 
 ### 1. Start: sync with develop
@@ -330,6 +463,7 @@ Vite SPA. Code is organized by feature under `apps/client/src/features/*` (mirro
 - The editor is Tiptap; shared node/mark extensions live in `packages/editor-ext` and are imported by **both the client and the server** (collaboration, schema, `canonicalizeFootnotes`) — editor schema changes often need to be made in `editor-ext`, not just the client. Server-side markdown import/export no longer lives in `editor-ext`: it goes through the canonical converter (#345, see below). The ProseMirror↔Markdown converter and its Docmost schema mirror now live in a SINGLE package, `@docmost/prosemirror-markdown` (#293), consumed by `mcp`, `git-sync`, and `apps/server` (#345) — 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. For the converter's property-testing and counterexample→fixture process (P1–P4 invariants, the `PROPERTY_SEED`/`PROPERTY_NUM_RUNS` knobs, and the nightly fuzz workflow), see `packages/prosemirror-markdown/README.md`.
 - 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`.
+- The build also emits `client/dist/version.json` (`{"version": …}`) from a small `vite.config.ts` plugin using the **same** `appVersion` that feeds `define.APP_VERSION`, so the file and the baked-in bundle version are identical by construction. The server reads it at startup (`ws.gateway.ts` via `readClientBuildVersion`/`resolveClientDistPath`) and announces it to each socket on connect (`app-version` event) so a tab left open across a redeploy can guard-reload before hitting a stale chunk (version-coherence). No runtime env / Dockerfile change — the file already ships in `client/dist`; missing/empty file ⇒ feature inert.
 
 ## Conventions
 

CHANGELOG.md

@@ -117,6 +117,18 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- **Open tabs pick up a new deploy on their own.** After the server is
+  redeployed while a tab is left open for hours, the tab now learns the new
+  build version over the existing WebSocket (announced per-connect, so a natural
+  reconnect delivers it) and shows a "A new version is available" banner with an
+  Update button. To avoid dropping a half-written comment or form, the tab is
+  not reloaded when you merely switch away from it; instead it auto-reloads at
+  the next safe point — the next in-app navigation (or immediately if you click
+  Update) — before it can hit a stale lazy-loaded chunk. At most one automatic
+  reload happens per browser session (shared with the existing chunk-load
+  recovery), so a permanent version skew degrades to the banner rather than a
+  reload loop. When the build carries no version info the feature stays inert.
+
 - **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

@@ -45,6 +45,11 @@ 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
+# The mcp package reads its data files (drawio-presets.json, drawio-shape-index.json.gz)
+# at runtime via `new URL("../../data/…", import.meta.url)` relative to build/lib/*.js,
+# i.e. from packages/mcp/data/. tsc emits only build/, so ship data/ explicitly or
+# drawioFromGraph and the shape catalog die with ENOENT on packages/mcp/data/*.
+COPY --from=builder /app/packages/mcp/data /app/packages/mcp/data
 # mcp now depends on @docmost/prosemirror-markdown (workspace:*) and eager-imports
 # it at runtime (the in-app ai-chat DocmostClient loads build/index.js -> lib/
 # markdown-converter.js). Ship the built package + its manifest, or the prod

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

@@ -1,4 +1,5 @@
 {
+  "A new version is available": "A new version is available",
   "Account": "Account",
   "Active": "Active",
   "Add": "Add",

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

@@ -1,4 +1,5 @@
 {
+  "A new version is available": "Доступна новая версия",
   "Account": "Аккаунт",
   "Active": "Активный",
   "Add": "Добавить",

apps/client/src/components/chunk-load-error-boundary.tsx

@@ -1,8 +1,11 @@
 import { ReactNode } from "react";
 import { ErrorBoundary } from "react-error-boundary";
 import { Button, Center, Stack, Text } from "@mantine/core";
-
+import {
-const RELOAD_FLAG = "chunk-reload-attempted";
+  hasAutoReloaded,
+  markAutoReloaded,
+  recordReloadBreadcrumb,
+} from "@/lib/reload-guard";
 
 // Heuristic detection of a failed dynamic import. Since the code-splitting work,
 // every route (plus Aside / AiChatWindow) is React.lazy: when a new deploy
@@ -25,16 +28,15 @@ function handleError(error: unknown) {
   if (!isChunkLoadError(error)) return;
   // A stale-chunk 404 is cured by a full reload that re-fetches index.html and
   // the new chunk manifest. Auto-reload once, guarding against a reload loop
-  // (e.g. a genuinely missing chunk) with a one-shot sessionStorage flag. If the
+  // (e.g. a genuinely missing chunk) with the shared one-shot session flag
-  // flag is already set we fall through to the manual recovery UI below.
+  // (see @/lib/reload-guard — shared with the proactive version-coherence
-  try {
+  // path). If it is already set, or the write fails (storage unavailable), we
-    if (sessionStorage.getItem(RELOAD_FLAG)) return;
+  // fall through to the manual recovery UI below rather than risk a loop.
-    sessionStorage.setItem(RELOAD_FLAG, "1");
+  if (hasAutoReloaded()) return;
-  } catch {
+  if (!markAutoReloaded()) return;
-    // sessionStorage unavailable (private mode / disabled): skip the automatic
+  // Trace before the reload clears the console (same diagnostic breadcrumb the
-    // reload rather than risk an unguarded loop; the fallback UI still recovers.
+  // proactive version-coherence path writes, tagged with this path).
-    return;
+  recordReloadBreadcrumb({ path: "chunk-boundary" });
-  }
   window.location.reload();
 }
 

apps/client/src/features/user/guarded-reload.test.tsx

@@ -0,0 +1,195 @@
+import { describe, it, expect, beforeEach, afterEach, vi } from "vitest";
+import { render, act, cleanup } from "@testing-library/react";
+import { MemoryRouter, useNavigate } from "react-router-dom";
+
+// Mocks for the dirty shell's side-effecting collaborators.
+vi.mock("@mantine/notifications", () => ({
+  notifications: { show: vi.fn() },
+}));
+vi.mock("@/i18n.ts", () => ({ default: { t: (k: string) => k } }));
+vi.mock("@/lib/reload-guard", () => ({
+  hasAutoReloaded: vi.fn(() => false),
+  markAutoReloaded: vi.fn(() => true),
+  recordReloadBreadcrumb: vi.fn(),
+  takeReloadBreadcrumb: vi.fn(() => null),
+}));
+
+import { notifications } from "@mantine/notifications";
+import { hasAutoReloaded, markAutoReloaded } from "@/lib/reload-guard";
+import {
+  triggerGuardedReload,
+  useVersionReloadOnNavigation,
+  __resetGuardedReloadForTests,
+} from "./guarded-reload";
+
+const show = notifications.show as unknown as ReturnType<typeof vi.fn>;
+const mockHasAutoReloaded = hasAutoReloaded as unknown as ReturnType<
+  typeof vi.fn
+>;
+const mockMarkAutoReloaded = markAutoReloaded as unknown as ReturnType<
+  typeof vi.fn
+>;
+
+let reload: ReturnType<typeof vi.fn>;
+let visibility: DocumentVisibilityState;
+
+// Test harness mounted inside a router: it installs the navigation hook and
+// exposes `navigate` so a test can drive an in-app router navigation.
+let doNavigate: (to: string) => void;
+function Harness() {
+  useVersionReloadOnNavigation();
+  const navigate = useNavigate();
+  doNavigate = navigate;
+  return null;
+}
+
+function mountHarness() {
+  render(
+    <MemoryRouter initialEntries={["/start"]}>
+      <Harness />
+    </MemoryRouter>,
+  );
+}
+
+function navigateTo(path: string) {
+  act(() => {
+    doNavigate(path);
+  });
+}
+
+beforeEach(() => {
+  __resetGuardedReloadForTests();
+  vi.clearAllMocks();
+  mockHasAutoReloaded.mockReturnValue(false);
+  mockMarkAutoReloaded.mockReturnValue(true);
+
+  vi.stubGlobal("APP_VERSION", "test-A");
+
+  reload = vi.fn();
+  Object.defineProperty(window, "location", {
+    configurable: true,
+    value: { reload },
+  });
+
+  visibility = "visible";
+  Object.defineProperty(document, "visibilityState", {
+    configurable: true,
+    get: () => visibility,
+  });
+});
+
+afterEach(() => {
+  cleanup();
+  vi.unstubAllGlobals();
+});
+
+describe("triggerGuardedReload (variant C)", () => {
+  it("noop when versions match: no banner, no reload", () => {
+    triggerGuardedReload("test-A");
+    expect(show).not.toHaveBeenCalled();
+    expect(reload).not.toHaveBeenCalled();
+  });
+
+  it("noop when the server version is empty (fail-safe)", () => {
+    triggerGuardedReload("");
+    triggerGuardedReload(undefined);
+    expect(show).not.toHaveBeenCalled();
+    expect(reload).not.toHaveBeenCalled();
+  });
+
+  it("real mismatch shows the banner but does NOT reload immediately", () => {
+    mountHarness();
+    triggerGuardedReload("test-B");
+    expect(show).toHaveBeenCalledTimes(1);
+    expect(show.mock.calls[0][0]).toMatchObject({
+      id: "app-version-reload",
+      autoClose: false,
+      withCloseButton: true,
+    });
+    expect(reload).not.toHaveBeenCalled();
+  });
+
+  it("reloads EXACTLY ONCE on the first in-app navigation after a mismatch", () => {
+    mountHarness();
+    triggerGuardedReload("test-B");
+    expect(reload).not.toHaveBeenCalled();
+
+    navigateTo("/next");
+    expect(reload).toHaveBeenCalledTimes(1);
+
+    // A second navigation must NOT reload again (one-shot was consumed).
+    navigateTo("/again");
+    expect(reload).toHaveBeenCalledTimes(1);
+  });
+
+  it("does NOT reload on a 2nd mismatch after the first was armed/consumed (one-shot)", () => {
+    mountHarness();
+    triggerGuardedReload("test-B");
+    navigateTo("/next");
+    expect(reload).toHaveBeenCalledTimes(1);
+
+    // Another app-version mismatch arrives (reconnect): must not re-arm.
+    triggerGuardedReload("test-C");
+    navigateTo("/again");
+    expect(reload).toHaveBeenCalledTimes(1);
+  });
+
+  it("does NOT reload merely from the tab going to the background", () => {
+    mountHarness();
+    triggerGuardedReload("test-B");
+    expect(reload).not.toHaveBeenCalled();
+
+    visibility = "hidden";
+    act(() => {
+      document.dispatchEvent(new Event("visibilitychange"));
+    });
+    expect(reload).not.toHaveBeenCalled();
+  });
+
+  it("a hidden-at-receipt tab is also NOT reloaded immediately (variant C uniform); reloads on next navigation", () => {
+    visibility = "hidden";
+    mountHarness();
+    triggerGuardedReload("test-B");
+    expect(reload).not.toHaveBeenCalled();
+    expect(show).toHaveBeenCalledTimes(1);
+
+    navigateTo("/next");
+    expect(reload).toHaveBeenCalledTimes(1);
+  });
+
+  it("the banner's Update button reloads immediately", () => {
+    triggerGuardedReload("test-B");
+    const message = show.mock.calls[0][0].message as {
+      props: { onClick: () => void };
+    };
+    message.props.onClick();
+    expect(reload).toHaveBeenCalledTimes(1);
+  });
+
+  it("banner-only (auto-reload already spent): banner, never auto-reload on navigation", () => {
+    mockHasAutoReloaded.mockReturnValue(true);
+    mountHarness();
+    triggerGuardedReload("test-B");
+    expect(show).toHaveBeenCalledTimes(1);
+
+    navigateTo("/next");
+    expect(reload).not.toHaveBeenCalled();
+  });
+
+  it("does NOT reload when the flag write fails; falls back to the banner", () => {
+    mockMarkAutoReloaded.mockReturnValue(false);
+    mountHarness();
+    triggerGuardedReload("test-B");
+    navigateTo("/next");
+    expect(reload).not.toHaveBeenCalled();
+    // performAutoReload falls back to showing the banner (initial + fallback).
+    expect(show).toHaveBeenCalled();
+  });
+
+  it("is idempotent within a tab-load: repeated emits do not stack banners", () => {
+    triggerGuardedReload("test-B");
+    triggerGuardedReload("test-B");
+    triggerGuardedReload("test-C");
+    expect(show).toHaveBeenCalledTimes(1);
+  });
+});

apps/client/src/features/user/guarded-reload.tsx

@@ -0,0 +1,187 @@
+import { useEffect, useRef } from "react";
+import { useLocation } from "react-router-dom";
+import { Button } from "@mantine/core";
+import { notifications } from "@mantine/notifications";
+import i18n from "@/i18n.ts";
+import {
+  hasAutoReloaded,
+  markAutoReloaded,
+  recordReloadBreadcrumb,
+  takeReloadBreadcrumb,
+} from "@/lib/reload-guard";
+import { decideVersionAction } from "@/features/user/version-coherence";
+
+// Dirty shell around the pure `decideVersionAction`: it reads globals
+// (APP_VERSION), touches sessionStorage via the shared reload-guard, drives the
+// Mantine notification, and arms the router-navigation reload hook. Kept
+// separate from the pure module so the decision stays unit-testable without a
+// DOM.
+
+// One fixed id so repeated app-version signals (e.g. every reconnect) update a
+// single banner instead of stacking a new one each time.
+const BANNER_ID = "app-version-reload";
+
+// Module-level idempotency for the current tab-load: once a mismatch has been
+// handled we don't re-arm the navigation reload or re-show the banner on
+// subsequent app-version emits.
+let handled = false;
+
+// Variant C: on a real mismatch we do NOT reload the tab when it merely goes to
+// the background (that would silently drop a half-written comment/form). Instead
+// we arm a one-shot reload for the NEXT in-app router navigation — a point where
+// the user is already leaving the current page, so an in-app navigation would
+// discard that unsaved component-state anyway and the reload adds no extra loss.
+let pendingNavReload = false;
+
+// Remembered from the last detected mismatch for the pre-reload breadcrumb and
+// the (already-visible) banner.
+let lastServerVersion = "";
+let lastClientVersion = "";
+
+// Read the build version baked into THIS bundle. The `typeof` guard avoids a
+// ReferenceError where the `APP_VERSION` global is absent (e.g. under vitest,
+// where Vite's `define` did not run) — an unknown client version makes the
+// pure decision no-op (fail-safe).
+function readClientVersion(): string {
+  return (typeof APP_VERSION !== "undefined" ? APP_VERSION : "").trim();
+}
+
+// Perform the actual reload — but only after the shared one-shot flag is
+// persisted. If the write fails (storage unavailable) we must NOT reload
+// (mirrors the reactive chunk-load boundary's `catch → return`), and fall back
+// to the manual banner so the user can still recover.
+function performAutoReload(): void {
+  if (!markAutoReloaded()) {
+    showReloadBanner();
+    return;
+  }
+  // Trace right before the reload (which clears the console): a persistent
+  // breadcrumb + a log line so the auto-reload is observable in a field report.
+  recordReloadBreadcrumb({
+    path: "proactive",
+    serverVersion: lastServerVersion,
+    clientVersion: lastClientVersion,
+  });
+  console.warn(
+    `[version-coherence] auto-reloading: client=${lastClientVersion} -> server=${lastServerVersion}`,
+  );
+  window.location.reload();
+}
+
+function showReloadBanner(): void {
+  notifications.show({
+    id: BANNER_ID,
+    title: i18n.t("A new version is available"),
+    message: (
+      <Button size="xs" mt="xs" onClick={() => performAutoReload()}>
+        {i18n.t("Update")}
+      </Button>
+    ),
+    autoClose: false,
+    withCloseButton: true,
+  });
+}
+
+/**
+ * Handle a server `app-version` announcement: compare it to this bundle's
+ * version and, on a real mismatch, show the banner and arm a guarded reload for
+ * the next in-app navigation (variant C).
+ *
+ * - real mismatch (first this session) → banner + arm navigation reload. The
+ *   banner's "Update" button reloads immediately (same one-shot guard). The tab
+ *   is NOT reloaded on visibility change.
+ * - auto-reload already used / storage error → banner only (no arm), so there is
+ *   at most one automatic reload per session (loop safety).
+ * - in sync / unknown version → noop (fail-safe).
+ */
+export function triggerGuardedReload(
+  rawServerVersion: string | undefined | null,
+): void {
+  const serverVersion = (rawServerVersion ?? "").trim();
+  const clientVersion = readClientVersion();
+
+  // A storage read error surfaces as autoReloadUsed=true → fail toward NOT
+  // reloading (banner only).
+  const autoReloadUsed = hasAutoReloaded();
+
+  const action = decideVersionAction({
+    serverVersion,
+    clientVersion,
+    autoReloadUsed,
+  });
+  if (action === "noop") return;
+
+  // Idempotent per tab-load: don't re-arm or re-stack the banner across repeated
+  // emits (reconnects) once we've already acted.
+  if (handled) return;
+  handled = true;
+
+  lastServerVersion = serverVersion;
+  lastClientVersion = clientVersion;
+
+  if (action === "banner") {
+    // Entered banner-only (permanent skew, node oscillation, or spent
+    // auto-reload). Log for diagnosability; show the manual banner.
+    console.warn(
+      `[version-coherence] server=${serverVersion} client=${clientVersion}: ` +
+        "auto-reload already spent this session — showing manual banner",
+    );
+    showReloadBanner();
+    return;
+  }
+
+  // action === "reload" (variant C): show the banner and defer the auto-reload
+  // to the next in-app navigation instead of reloading now / on visibility.
+  showReloadBanner();
+  pendingNavReload = true;
+}
+
+/**
+ * Consume the armed one-shot navigation reload, if any. Called by
+ * `useVersionReloadOnNavigation` on each in-app router navigation.
+ */
+export function consumeNavigationReload(): void {
+  if (!pendingNavReload) return;
+  pendingNavReload = false;
+  performAutoReload();
+}
+
+/**
+ * Hook (mounted inside the Router) that fires the armed one-shot reload on the
+ * NEXT in-app router navigation after a version mismatch. Skips the initial
+ * render so it only reacts to real navigations, not the first location.
+ */
+export function useVersionReloadOnNavigation(): void {
+  const location = useLocation();
+  const firstRender = useRef(true);
+  useEffect(() => {
+    if (firstRender.current) {
+      firstRender.current = false;
+      return;
+    }
+    consumeNavigationReload();
+  }, [location.key]);
+}
+
+/**
+ * Surface (log once) the breadcrumb left by an auto-reload in the previous page
+ * load — the reload cleared the console, so this makes a "tab reloaded itself"
+ * report diagnosable. Call once on app startup.
+ */
+export function surfacePreviousReloadBreadcrumb(): void {
+  const crumb = takeReloadBreadcrumb();
+  if (!crumb) return;
+  console.info(
+    `[version-coherence] previous auto-reload: path=${crumb.path} ` +
+      `client=${crumb.clientVersion ?? ""} -> server=${crumb.serverVersion ?? ""} ` +
+      `at=${new Date(crumb.at).toISOString()}`,
+  );
+}
+
+// Test-only: reset module-level latches between cases.
+export function __resetGuardedReloadForTests(): void {
+  handled = false;
+  pendingNavReload = false;
+  lastServerVersion = "";
+  lastClientVersion = "";
+}

apps/client/src/features/user/user-provider.tsx

@@ -13,6 +13,12 @@ import { useCollabToken } from "@/features/auth/queries/auth-query.tsx";
 import { Error404 } from "@/components/ui/error-404.tsx";
 import { queryClient } from "@/main.tsx";
 import { makeConnectHandler } from "@/features/user/connect-resync.ts";
+import {
+  triggerGuardedReload,
+  useVersionReloadOnNavigation,
+  surfacePreviousReloadBreadcrumb,
+} from "@/features/user/guarded-reload.tsx";
+import type { AppVersionSocketPayload } from "@/features/user/version-coherence.ts";
 
 export function UserProvider({ children }: React.PropsWithChildren) {
   const [, setCurrentUser] = useAtom(currentUserAtom);
@@ -22,6 +28,16 @@ export function UserProvider({ children }: React.PropsWithChildren) {
   // fetch collab token on load
   const { data: collab } = useCollabToken();
 
+  // version-coherence: fire the armed one-shot reload on the next in-app
+  // navigation (variant C — a safe point, not on tab backgrounding).
+  useVersionReloadOnNavigation();
+
+  // Surface any breadcrumb left by an auto-reload in the previous page load
+  // (the reload cleared the console) so a field report stays diagnosable.
+  useEffect(() => {
+    surfacePreviousReloadBreadcrumb();
+  }, []);
+
   useEffect(() => {
     if (isLoading || isError) {
       return;
@@ -47,6 +63,16 @@ export function UserProvider({ children }: React.PropsWithChildren) {
       handleConnect();
     });
 
+    // Register the version-coherence listener SYNCHRONOUSLY, before the socket
+    // connects: the server emits `app-version` immediately in handleConnection,
+    // so a listener attached after connect would miss it on a fast localhost
+    // connect. On a version mismatch the client shows a banner and defers the
+    // auto-reload to the next in-app navigation (variant C — avoids reloading a
+    // backgrounded tab that may hold unsaved input) before it hits a stale chunk.
+    newSocket.on("app-version", (payload?: AppVersionSocketPayload) => {
+      triggerGuardedReload(payload?.version);
+    });
+
     return () => {
       console.log("ws disconnected");
       newSocket.disconnect();

apps/client/src/features/user/version-coherence.test.ts

@@ -0,0 +1,64 @@
+import { describe, it, expect } from "vitest";
+import { decideVersionAction } from "./version-coherence";
+
+describe("decideVersionAction", () => {
+  it("noop when the server version is empty (fail-safe)", () => {
+    expect(
+      decideVersionAction({
+        serverVersion: "",
+        clientVersion: "v1",
+        autoReloadUsed: false,
+      }),
+    ).toBe("noop");
+  });
+
+  it("noop when the client version is empty (fail-safe)", () => {
+    expect(
+      decideVersionAction({
+        serverVersion: "v1",
+        clientVersion: "",
+        autoReloadUsed: false,
+      }),
+    ).toBe("noop");
+  });
+
+  it("noop when versions are equal (in sync)", () => {
+    expect(
+      decideVersionAction({
+        serverVersion: "v1",
+        clientVersion: "v1",
+        autoReloadUsed: false,
+      }),
+    ).toBe("noop");
+  });
+
+  it("reload on a real mismatch the first time this session", () => {
+    expect(
+      decideVersionAction({
+        serverVersion: "test-B",
+        clientVersion: "test-A",
+        autoReloadUsed: false,
+      }),
+    ).toBe("reload");
+  });
+
+  it("banner on a mismatch once the session auto-reload is spent", () => {
+    expect(
+      decideVersionAction({
+        serverVersion: "test-B",
+        clientVersion: "test-A",
+        autoReloadUsed: true,
+      }),
+    ).toBe("banner");
+  });
+
+  it("equal versions stay noop even if auto-reload was already used", () => {
+    expect(
+      decideVersionAction({
+        serverVersion: "v1",
+        clientVersion: "v1",
+        autoReloadUsed: true,
+      }),
+    ).toBe("noop");
+  });
+});

apps/client/src/features/user/version-coherence.ts

@@ -0,0 +1,32 @@
+// Payload of the per-connect `app-version` socket.io event announced by the
+// server (ws.gateway.ts) after a successful auth. A dedicated event — NOT a
+// member of the room-scoped `WebSocketEvent` union (which is discriminated by
+// `operation`), so it never touches use-query-subscription.
+export type AppVersionSocketPayload = { version: string };
+
+/**
+ * Pure decision for the version-coherence guard.
+ *
+ * All inputs are injected (no globals, no side effects) so it is unit-testable
+ * without a DOM or the build-time `APP_VERSION` global (undefined under vitest).
+ *
+ * - `autoReloadUsed` = a session-wide automatic reload has already happened,
+ *   so we must not auto-reload again (loop safety, shared with the reactive
+ *   chunk-load boundary).
+ *
+ * Returns:
+ * - "noop"   — do nothing (unknown version on either side, or already in sync).
+ * - "banner" — show the manual "update available" banner only (no auto-reload).
+ * - "reload" — real first-time mismatch: eligible for a guarded auto-reload.
+ */
+export function decideVersionAction(args: {
+  serverVersion: string;
+  clientVersion: string;
+  autoReloadUsed: boolean;
+}): "reload" | "banner" | "noop" {
+  const { serverVersion, clientVersion, autoReloadUsed } = args;
+  if (!serverVersion || !clientVersion) return "noop"; // fail-safe: unknown version → never act
+  if (serverVersion === clientVersion) return "noop"; // in sync
+  if (autoReloadUsed) return "banner"; // one auto-reload per session already spent
+  return "reload"; // real mismatch, first time this session
+}

apps/client/src/lib/reload-guard.test.ts

@@ -0,0 +1,97 @@
+import { describe, it, expect, beforeEach, afterEach, vi } from "vitest";
+import {
+  hasAutoReloaded,
+  markAutoReloaded,
+  recordReloadBreadcrumb,
+  takeReloadBreadcrumb,
+} from "./reload-guard";
+
+const FLAG = "chunk-reload-attempted";
+
+describe("reload-guard", () => {
+  beforeEach(() => {
+    sessionStorage.clear();
+    vi.restoreAllMocks();
+  });
+
+  afterEach(() => {
+    sessionStorage.clear();
+    vi.restoreAllMocks();
+  });
+
+  it("hasAutoReloaded is false before any reload, true after mark", () => {
+    expect(hasAutoReloaded()).toBe(false);
+    expect(markAutoReloaded()).toBe(true);
+    expect(hasAutoReloaded()).toBe(true);
+    // Uses the same key the reactive chunk-load boundary reads.
+    expect(sessionStorage.getItem(FLAG)).toBe("1");
+  });
+
+  it("hasAutoReloaded returns true when reading storage throws (fail toward not reloading)", () => {
+    vi.stubGlobal("sessionStorage", {
+      getItem: () => {
+        throw new Error("storage disabled");
+      },
+      setItem: () => {
+        throw new Error("storage disabled");
+      },
+    });
+    try {
+      expect(hasAutoReloaded()).toBe(true);
+    } finally {
+      vi.unstubAllGlobals();
+    }
+  });
+
+  it("markAutoReloaded returns false when writing storage throws", () => {
+    vi.stubGlobal("sessionStorage", {
+      getItem: () => null,
+      setItem: () => {
+        throw new Error("storage disabled");
+      },
+    });
+    try {
+      expect(markAutoReloaded()).toBe(false);
+    } finally {
+      vi.unstubAllGlobals();
+    }
+  });
+
+  it("records and then takes a breadcrumb once (cleared on read)", () => {
+    recordReloadBreadcrumb({
+      path: "proactive",
+      serverVersion: "test-B",
+      clientVersion: "test-A",
+    });
+    const crumb = takeReloadBreadcrumb();
+    expect(crumb).toMatchObject({
+      path: "proactive",
+      serverVersion: "test-B",
+      clientVersion: "test-A",
+    });
+    expect(typeof crumb?.at).toBe("number");
+    // Cleared on read → a second take returns null.
+    expect(takeReloadBreadcrumb()).toBeNull();
+  });
+
+  it("takeReloadBreadcrumb returns null when nothing was recorded", () => {
+    expect(takeReloadBreadcrumb()).toBeNull();
+  });
+
+  it("recordReloadBreadcrumb swallows a storage-write error (diagnostics only)", () => {
+    vi.stubGlobal("sessionStorage", {
+      getItem: () => null,
+      setItem: () => {
+        throw new Error("storage disabled");
+      },
+      removeItem: () => {},
+    });
+    try {
+      expect(() =>
+        recordReloadBreadcrumb({ path: "chunk-boundary" }),
+      ).not.toThrow();
+    } finally {
+      vi.unstubAllGlobals();
+    }
+  });
+});

apps/client/src/lib/reload-guard.ts

@@ -0,0 +1,90 @@
+// Shared one-shot auto-reload guard.
+//
+// Both auto-reload paths — the reactive chunk-load-error-boundary (recovers
+// AFTER a stale lazy chunk 404s) and the proactive version-coherence feature
+// (reloads BEFORE the tab hits a stale chunk) — go through these functions so
+// they share ONE session-scoped flag. Net guarantee: at most a single
+// automatic reload per browser session across both paths. Once the flag is set
+// (or sessionStorage is unavailable), every further mismatch degrades to a
+// manual banner/UI — no reload loop under permanent skew, node oscillation, or
+// a disabled storage.
+const RELOAD_FLAG = "chunk-reload-attempted";
+
+/**
+ * Has an automatic reload already been performed (or attempted) this session?
+ *
+ * A storage read error (private mode / disabled) is reported as `true` so the
+ * caller fails toward NOT reloading — an unguarded loop is worse than a stale
+ * tab the user can reload manually.
+ */
+export function hasAutoReloaded(): boolean {
+  try {
+    return sessionStorage.getItem(RELOAD_FLAG) !== null;
+  } catch {
+    return true;
+  }
+}
+
+/**
+ * Record that an automatic reload is being performed this session.
+ *
+ * Returns whether the write succeeded. A `false` return (storage unavailable)
+ * means the caller MUST NOT reload — otherwise the flag would never stick and
+ * the reload could loop.
+ */
+export function markAutoReloaded(): boolean {
+  try {
+    sessionStorage.setItem(RELOAD_FLAG, "1");
+    return true;
+  } catch {
+    return false;
+  }
+}
+
+// Diagnostic breadcrumb for an automatic reload. Written right before
+// window.location.reload() (which clears the console) and read back on the next
+// page load, so a "the tab reloaded itself / it's looping" field report is
+// diagnosable: which path fired (proactive version-coherence vs the reactive
+// chunk-load boundary) and which version pair triggered it. sessionStorage
+// survives a same-tab reload, unlike the console.
+const RELOAD_BREADCRUMB_KEY = "reload-breadcrumb";
+
+export type ReloadBreadcrumb = {
+  path: "proactive" | "chunk-boundary";
+  serverVersion?: string;
+  clientVersion?: string;
+  at: number;
+};
+
+/**
+ * Persist a best-effort breadcrumb just before an automatic reload. Failures
+ * (storage unavailable) are swallowed — this is diagnostics only and must never
+ * block or alter the reload decision.
+ */
+export function recordReloadBreadcrumb(
+  entry: Omit<ReloadBreadcrumb, "at">,
+): void {
+  try {
+    sessionStorage.setItem(
+      RELOAD_BREADCRUMB_KEY,
+      JSON.stringify({ ...entry, at: Date.now() }),
+    );
+  } catch {
+    // best-effort diagnostics only
+  }
+}
+
+/**
+ * Read and clear the breadcrumb left by an auto-reload in the previous page
+ * load. Cleared on read so it surfaces exactly once per reload.
+ */
+export function takeReloadBreadcrumb(): ReloadBreadcrumb | null {
+  try {
+    const raw = sessionStorage.getItem(RELOAD_BREADCRUMB_KEY);
+    if (!raw) return null;
+    sessionStorage.removeItem(RELOAD_BREADCRUMB_KEY);
+    return JSON.parse(raw) as ReloadBreadcrumb;
+  } catch {
+    return null;
+  }
+}

apps/client/vite.config.ts

@@ -1,7 +1,8 @@
-import { defineConfig, loadEnv } from "vite";
+import { defineConfig, loadEnv, type Plugin } from "vite";
 import react from "@vitejs/plugin-react";
 import { compression } from "vite-plugin-compression2";
 import * as path from "path";
+import * as fs from "node:fs";
 import { execSync } from "node:child_process";
 
 const envPath = path.resolve(process.cwd(), "..", "..");
@@ -24,7 +25,32 @@ function resolveAppVersion(cwd: string): string {
   }
 }
 
+// Emit <outDir>/version.json = { "version": appVersion } so the server can read
+// the exact same build id the bundle was compiled with. The value is the SAME
+// `appVersion` fed into `define.APP_VERSION`, so version.json and the baked-in
+// global are identical by construction — the single source of truth (no
+// runtime-env second copy that could drift and cause a false version mismatch).
+function versionJsonPlugin(version: string): Plugin {
+  let outDir = "dist";
+  return {
+    name: "emit-version-json",
+    apply: "build",
+    configResolved(config) {
+      outDir = config.build.outDir;
+    },
+    writeBundle() {
+      const root = path.resolve(process.cwd(), outDir);
+      fs.mkdirSync(root, { recursive: true });
+      fs.writeFileSync(
+        path.join(root, "version.json"),
+        JSON.stringify({ version }),
+      );
+    },
+  };
+}
+
 export default defineConfig(({ mode }) => {
+  const appVersion = resolveAppVersion(envPath);
   const {
     APP_URL,
     FILE_UPLOAD_SIZE_LIMIT,
@@ -52,10 +78,11 @@ export default defineConfig(({ mode }) => {
         POSTHOG_HOST,
         POSTHOG_KEY,
       },
-      APP_VERSION: JSON.stringify(resolveAppVersion(envPath)),
+      APP_VERSION: JSON.stringify(appVersion),
     },
     plugins: [
       react(),
+      versionJsonPlugin(appVersion),
       // Emit .br and .gz next to every built asset so the server can serve the
       // precompressed copy (see @fastify/static preCompressed in static.module.ts).
       compression({

apps/server/src/common/helpers/client-version.spec.ts

@@ -0,0 +1,52 @@
+import { join } from 'path';
+import * as fs from 'node:fs';
+import * as os from 'node:os';
+import { readClientBuildVersion } from './client-version';
+
+describe('readClientBuildVersion', () => {
+  let dir: string;
+
+  beforeEach(() => {
+    dir = fs.mkdtempSync(join(os.tmpdir(), 'client-version-'));
+  });
+
+  afterEach(() => {
+    fs.rmSync(dir, { recursive: true, force: true });
+  });
+
+  const writeVersionJson = (content: string) =>
+    fs.writeFileSync(join(dir, 'version.json'), content);
+
+  it('returns the version from a valid version.json', () => {
+    writeVersionJson(JSON.stringify({ version: 'test-A' }));
+    expect(readClientBuildVersion(dir)).toBe('test-A');
+  });
+
+  it('trims surrounding whitespace in the version', () => {
+    writeVersionJson(JSON.stringify({ version: '  v1.2.3  ' }));
+    expect(readClientBuildVersion(dir)).toBe('v1.2.3');
+  });
+
+  it('returns "" when version.json is missing', () => {
+    expect(readClientBuildVersion(dir)).toBe('');
+  });
+
+  it('returns "" on malformed JSON', () => {
+    writeVersionJson('{ not json');
+    expect(readClientBuildVersion(dir)).toBe('');
+  });
+
+  it('returns "" when the version field is absent', () => {
+    writeVersionJson(JSON.stringify({ notVersion: 'x' }));
+    expect(readClientBuildVersion(dir)).toBe('');
+  });
+
+  it('returns "" when the version field is not a string', () => {
+    writeVersionJson(JSON.stringify({ version: 123 }));
+    expect(readClientBuildVersion(dir)).toBe('');
+  });
+
+  it('returns "" when the path does not exist at all', () => {
+    expect(readClientBuildVersion(join(dir, 'nope'))).toBe('');
+  });
+});

apps/server/src/common/helpers/client-version.ts

@@ -0,0 +1,36 @@
+import { join } from 'path';
+import * as fs from 'node:fs';
+
+/**
+ * Resolve the absolute path to the built client bundle directory
+ * (`apps/client/dist`) shipped into the runtime image.
+ *
+ * The `../` depth is anchored on THIS module's compiled location
+ * (`dist/common/helpers`). `integrations/static` sits at the same depth under
+ * the compiled root, so both callers (StaticModule and readClientBuildVersion)
+ * MUST share this single helper rather than duplicating the depth — a copy in a
+ * module at a different depth would silently resolve to the wrong directory.
+ */
+export function resolveClientDistPath(): string {
+  return join(__dirname, '..', '..', '..', '..', 'client/dist');
+}
+
+/**
+ * Read the build version the client bundle was compiled with, from
+ * `<clientDistPath>/version.json` (written by the Vite build — the single
+ * source of truth shared by the baked-in `APP_VERSION` global and this file).
+ *
+ * Fail-safe: any error (missing file, unreadable, bad JSON, non-string
+ * version) yields `''`. The caller treats an empty version as "unknown" and
+ * the whole version-coherence feature stays silently inert — existing deploys
+ * without the file keep working unchanged.
+ */
+export function readClientBuildVersion(clientDistPath: string): string {
+  try {
+    const raw = fs.readFileSync(join(clientDistPath, 'version.json'), 'utf8');
+    const version = (JSON.parse(raw) as { version?: unknown }).version;
+    return typeof version === 'string' ? version.trim() : '';
+  } catch {
+    return '';
+  }
+}

apps/server/src/common/helpers/index.ts

@@ -3,3 +3,4 @@ export * from './nanoid.utils';
 export * from './file.helper';
 export * from './constants';
 export * from './security-headers';
+export * from './client-version';

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

@@ -27,10 +27,12 @@ import type { DocmostClientLike } from './docmost-client.loader';
  */
 
 describe('tool tier metadata (#332)', () => {
-  it('core set is the documented 13 + searchInPage + insertFootnote (15)', () => {
+  it('core set is the documented 13 + searchInPage + insertFootnote + getTree + getPageContext (17, #443)', () => {
-    expect(CORE_TOOL_KEYS).toHaveLength(15);
+    expect(CORE_TOOL_KEYS).toHaveLength(17);
     expect(CORE_TOOL_SET.has('searchInPage')).toBe(true); // #330, promoted to core
     expect(CORE_TOOL_SET.has('insertFootnote')).toBe(true); // #410, promoted to core
+    expect(CORE_TOOL_SET.has('getTree')).toBe(true); // #443, promoted to core
+    expect(CORE_TOOL_SET.has('getPageContext')).toBe(true); // #443, promoted to core
     // loadTools is a meta-tool, not a normal core key.
     expect(CORE_TOOL_SET.has(LOAD_TOOLS_NAME)).toBe(false);
   });

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

@@ -39,12 +39,14 @@ export interface ToolCatalogEntry {
 
 /**
  * CORE (always-active) in-app tool keys — 13 frequent/tiny tools + `searchInPage`
- * (#330) + `insertFootnote` (#410). `searchInPage` is core because it is frequent
+ * (#330) + `insertFootnote` (#410) + `getTree`/`getPageContext` (#443).
- * for the editorial roles this feature targets; `insertFootnote` is core so the
+ * `searchInPage` is core because it is frequent for the editorial roles this
- * footnote tool is NOT hidden while its natural sibling `editPageText` is always
+ * feature targets; `insertFootnote` is core so the footnote tool is NOT hidden
- * active (that asymmetry is exactly what pushed the agent to write literal
+ * while its natural sibling `editPageText` is always active (that asymmetry is
- * `^[...]`). `loadTools` is active too but is not a normal tool key (it is added
+ * exactly what pushed the agent to write literal `^[...]`). `getTree` and
- * to activeTools separately).
+ * `getPageContext` are the single-call navigation/lookup tools — core so the
+ * agent never has to loadTools just to orient itself. `loadTools` is active too
+ * but is not a normal tool key (it is added to activeTools separately).
  */
 export const CORE_TOOL_KEYS = [
   'searchPages',
@@ -66,6 +68,11 @@ export const CORE_TOOL_KEYS = [
   // #410 insertFootnote — core so pinpoint citations to already-written text
   // don't degrade into literal `^[...]`; kept symmetric with editPageText.
   'insertFootnote',
+  // #443 getTree + getPageContext — cheap single-call navigation/lookup tools
+  // (the core listPages even points to getTree); core so the agent never has
+  // to loadTools just to orient itself.
+  'getTree',
+  'getPageContext',
 ] as const;
 
 /** O(1) membership test for the core tier. */

apps/server/src/integrations/static/static.module.ts

@@ -4,6 +4,7 @@ import { join } from 'path';
 import * as fs from 'node:fs';
 import fastifyStatic from '@fastify/static';
 import { EnvironmentService } from '../environment/environment.service';
+import { resolveClientDistPath } from '../../common/helpers/client-version';
 
 /**
  * Resolve the response headers for a statically served client asset.
@@ -56,14 +57,7 @@ export class StaticModule implements OnModuleInit {
     const httpAdapter = this.httpAdapterHost.httpAdapter;
     const app = httpAdapter.getInstance();
 
-    const clientDistPath = join(
+    const clientDistPath = resolveClientDistPath();
-      __dirname,
-      '..',
-      '..',
-      '..',
-      '..',
-      'client/dist',
-    );
 
     const indexFilePath = join(clientDistPath, 'index.html');
 

apps/server/src/ws/ws.gateway.ts

@@ -9,10 +9,14 @@ import {
 import { Server, Socket } from 'socket.io';
 import { TokenService } from '../core/auth/services/token.service';
 import { JwtPayload, JwtType } from '../core/auth/dto/jwt-payload';
-import { OnModuleDestroy } from '@nestjs/common';
+import { Logger, OnModuleDestroy, OnModuleInit } from '@nestjs/common';
 import { SpaceMemberRepo } from '@docmost/db/repos/space/space-member.repo';
 import { WsService } from './ws.service';
 import { getSpaceRoomName, getUserRoomName } from './ws.utils';
+import {
+  readClientBuildVersion,
+  resolveClientDistPath,
+} from '../common/helpers/client-version';
 import * as cookie from 'cookie';
 
 @WebSocketGateway({
@@ -20,17 +24,40 @@ import * as cookie from 'cookie';
   transports: ['websocket'],
 })
 export class WsGateway
-  implements OnGatewayConnection, OnGatewayInit, OnModuleDestroy
+  implements
+    OnGatewayConnection,
+    OnGatewayInit,
+    OnModuleInit,
+    OnModuleDestroy
 {
   @WebSocketServer()
   server: Server;
 
+  private readonly logger = new Logger(WsGateway.name);
+
+  // The build version of the client bundle shipped in this image, read once at
+  // startup from client/dist/version.json (single source of truth, same value
+  // baked into the client's APP_VERSION). Empty string => version.json missing
+  // or empty => the proactive version-coherence reload feature stays inert.
+  private appVersion = '';
+
   constructor(
     private tokenService: TokenService,
     private spaceMemberRepo: SpaceMemberRepo,
     private wsService: WsService,
   ) {}
 
+  onModuleInit(): void {
+    this.appVersion = readClientBuildVersion(resolveClientDistPath());
+    if (this.appVersion) {
+      this.logger.log(`app-version reload: ACTIVE (v=${this.appVersion})`);
+    } else {
+      this.logger.log(
+        'app-version reload: DISABLED (version.json missing/empty)',
+      );
+    }
+  }
+
   afterInit(server: Server): void {
     this.wsService.setServer(server);
   }
@@ -55,6 +82,14 @@ export class WsGateway
       const spaceRooms = userSpaceIds.map((id) => getSpaceRoomName(id));
 
       client.join([userRoom, workspaceRoom, ...spaceRooms]);
+
+      // Announce this container's client build version to the freshly
+      // authenticated socket. On a redeploy the client reconnects to the new
+      // container and receives the new version here, letting it guard-reload
+      // before it hits a stale lazy chunk. Per-connect only (no broadcast):
+      // natural reconnect covers both single-container and cluster without a
+      // thundering-herd fleet reload.
+      client.emit('app-version', { version: this.appVersion });
     } catch (err) {
       client.emit('Unauthorized');
       client.disconnect();

packages/mcp/test-e2e.mjs

@@ -316,7 +316,8 @@ async function main() {
         const [idA, idB, idC] = seedIds;
 
         // patchNode: replace the middle paragraph; siblings' ids must be unchanged.
-        await client.patchNode(nid, idB, mkPara(idB, "Bravo PATCHED."));
+        // #413 XOR input: the raw ProseMirror node goes under the `node` key.
+        await client.patchNode(nid, idB, { node: mkPara(idB, "Bravo PATCHED.") });
         await new Promise((r) => setTimeout(r, 16000));
         const afterPatch = (await client.getPageJson(nid)).content;
         const patchText = JSON.stringify(afterPatch);
@@ -327,7 +328,7 @@ async function main() {
         // insertNode: place a new block after the first paragraph.
         await client.insertNode(
           nid,
-          mkPara("nodeops-ins", "Inserted paragraph."),
+          { node: mkPara("nodeops-ins", "Inserted paragraph.") },
           { position: "after", anchorNodeId: idA },
         );
         await new Promise((r) => setTimeout(r, 16000));