fix(#370): ревью r4 — F8-близнец в handleSaveVersion + утечка idleBurstStart

WARNING 1 [stability]: handleSaveVersion — write-path-близнец F8-бага. Деструктивный
popContributors (Redis SPOP, не откатывается с PG-tx) внутри executeTx; commit-abort
реджектит СНАРУЖИ колбэка, inner-catch не срабатывает → потеря атрибуции. Фикс:
poppedForRestore/versionedPageId объявлены ДО executeTx + внешний try/catch
восстанавливает (идемпотентный addContributors) на любом tx/commit-abort throw;
inner-catch обнуляет трекер после своего восстановления. Ровно одно восстановление
в каждой ветке. Зеркалит history.processor.ts (F8).

WARNING 2 [stability]: idleBurstStart Map текла + промахивалась по ключу. Рекей
page.id->documentName (как сиблинги) + cleanup в afterUnloadDocument; хаускипинг:
remove idle-job по page.id (реальный jobId), delete маркер по documentName —
page.<slugId> (#260) больше не промахивается.

Simplification: history-list переиспользует historyKindMeta().version.
+3 теста (F8-twin restore, slugId housekeeping, Map cleanup), mutation-verified.

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

.env.example

@@ -302,16 +302,6 @@ MCP_DOCMOST_PASSWORD=
 # enabled for a workspace, and the same single-instance constraint applies (the
 # registry is process-local).
 # AI_CHAT_RESUMABLE_STREAM=false
-#
-# Per-run replay ring cap (#491), in BYTES, for the resumable-stream registry
-# above. The registry buffers the run's recent SSE tail so a reopened tab can
-# attach and continue from the step it already persisted; the ring is bounded and
-# rotates on every confirmed step-persist. This caps the un-persisted tail between
-# rotations — an overflow evicts the oldest frames and a late attach falls back to
-# 204 -> degraded poll, so correctness never depends on the size. Default 4194304
-# (4MB); a 0/invalid value falls back to the default. The per-subscriber backpressure
-# cap is derived as 2x this value. Only meaningful with AI_CHAT_RESUMABLE_STREAM on.
-# AI_CHAT_RUN_STREAM_MAX_BUFFER_BYTES=4194304
 
 # --- Run lifecycle tunables (#487) ---
 # These govern the universal run machinery (every turn is now a first-class run,

.gitignore

@@ -29,10 +29,6 @@ packages/mcp/build/
 # is a build artifact like build/ — never committed, always fresh.
 packages/mcp/src/registry-stamp.generated.ts
 
-# token-estimate compiled output (#490; built in CI/Docker via `pnpm build` /
-# the server `pretest`, never committed, so src/ and prod can never diverge).
-packages/token-estimate/dist/
-
 # Logs
 logs
 *.log

CHANGELOG.md

@@ -129,6 +129,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- **Save intentional page versions.** Press `Cmd/Ctrl+S` (or use the page menu)
+  to save a named version of a page. The history panel now distinguishes
+  intentional versions (a "Saved" / "Agent version" badge) from automatic
+  snapshots, dims autosaves, and offers an "Only versions" filter. Automatic
+  snapshots switched from a fixed interval to a trailing idle-flush with a
+  max-wait ceiling, and a boundary snapshot is pinned whenever the editing source
+  changes (e.g. a person's edits followed by the AI agent). (#370)
+
 - **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
@@ -336,27 +344,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
-- **A long AI chat no longer bricks on the model's context window, and each turn
-  stops re-persisting the whole tool-output history.** Tool outputs are now
-  stored ONCE, in `metadata.parts`; the `tool_calls` trace keeps only per-step
-  outcome flags (a v2 trace shape), ending the O(N²) write amplification that
-  re-wrote every prior output on every step (measured on a live Postgres via the
-  `pg_current_wal_lsn()` delta: the trace column shrank ~3200×, the full
-  assistant row ~51%). The persisted record is unchanged in content — the full
-  history still lives in `metadata.parts`. At REPLAY time only, the history sent
-  to the provider is now bounded by a deterministic, prompt-cache-friendly token
-  budget: `floor(0.7 × chatContextWindow)` when a window is configured (no cap —
-  anti-brick protection, not a cost limiter), a flat 100k fallback for installs
-  with no window set (exactly the ones that hit terminal overflow), or off when
-  the window is explicitly `0`. Trimming truncates old tool outputs first, then
-  mechanically collapses the oldest turns, always keeping the recent turns full
-  and the tool-call/result pairing balanced. A provider context-overflow 400 is
-  now classified and used as a reactive signal: the row is stamped so the NEXT
-  turn re-trims aggressively (0.5×), which un-bricks a chat that just 400'd. The
-  client token badge and the server budgeter now share one estimator (new
-  `@docmost/token-estimate` package) so they can never diverge. Deferred-tool
-  activation is also cached in the chat metadata to avoid re-resolving it each
-  turn. (#490)
 - **A chat with one malformed message part no longer 500s on every turn, and a
   failed send no longer duplicates the user's message.** Incoming client parts
   are now whitelisted to `text` (a forged tool-result part can no longer reach

apps/client/package.json

@@ -22,7 +22,6 @@
     "@casl/react": "5.0.1",
     "@docmost/editor-ext": "workspace:*",
     "@docmost/prosemirror-markdown": "workspace:*",
-    "@docmost/token-estimate": "workspace:*",
     "@excalidraw/excalidraw": "0.18.0-3a5ef40",
     "@mantine/core": "8.3.18",
     "@mantine/dates": "8.3.18",

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

@@ -1418,5 +1418,14 @@
   "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"
+  "Failed to dismiss suggestion": "Failed to dismiss suggestion",
+  "Save version": "Save version",
+  "Ctrl+S": "Ctrl+S",
+  "Version saved": "Version saved",
+  "Already saved as the latest version": "Already saved as the latest version",
+  "Agent version": "Agent version",
+  "Boundary": "Boundary",
+  "Autosave": "Autosave",
+  "Only versions": "Only versions",
+  "No saved versions yet.": "No saved versions yet."
 }

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

@@ -1281,5 +1281,14 @@
   "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"
+  "Failed to dismiss suggestion": "Не удалось отклонить предложение",
+  "Save version": "Сохранить версию",
+  "Ctrl+S": "Ctrl+S",
+  "Version saved": "Версия сохранена",
+  "Already saved as the latest version": "Уже сохранено как последняя версия",
+  "Agent version": "Версия агента",
+  "Boundary": "Граница",
+  "Autosave": "Автосейв",
+  "Only versions": "Только версии",
+  "No saved versions yet.": "Пока нет сохранённых версий."
 }

apps/client/src/features/ai-chat/components/ai-chat-window.tsx

@@ -58,11 +58,8 @@ import ConversationList from "@/features/ai-chat/components/conversation-list.ts
 import ChatThread from "@/features/ai-chat/components/chat-thread.tsx";
 import {
   exportAiChat,
-  getAiChatMessagesDelta,
   stopRun,
 } from "@/features/ai-chat/services/ai-chat-service.ts";
-import { mergeDeltaRowsIntoPages } from "@/features/ai-chat/utils/resume-helpers.ts";
-import type { IAiChatMessageRow } from "@/features/ai-chat/types/ai-chat.types.ts";
 import { useChatSession } from "@/features/ai-chat/hooks/use-chat-session.ts";
 import {
   shouldCollapseOnOutsidePointer,
@@ -272,64 +269,17 @@ export default function AiChatWindow() {
   const { data: messageRows, isLoading: messagesLoading } =
     useAiChatMessagesQuery(
       activeChatId ?? undefined,
-      // #491: the full infinite-query no longer POLLS. It seeds the thread ONCE; the
-      // degraded fallback now runs a DELTA poller (below) that augments THIS cache
-      // idempotently, instead of refetching every page (with full parts) every 2.5s.
-      false,
-      // #344: gate on windowOpen too — no message history is fetched while the window
-      // is closed; it loads when the window opens with an active chat.
+      // DELIBERATELY DUMB: poll every 2.5s WHILE ARMED, otherwise off. NO error
+      // checks (TanStack resets fetchFailureCount each fetch; the poll must survive
+      // a server restart), NO tail checks, NO cap here — the settled/stalled/idle-cap
+      // semantics all live in ChatThread's FSM, which disarms via onResumeFallback.
+      () => (degradedPoll === true ? 2500 : false),
+      // #344: gate on windowOpen too — no message history is fetched (and no
+      // degraded poll runs) while the window is closed; it loads when the window
+      // opens with an active chat.
       windowOpen,
     );
 
-  // #491 degraded DELTA poll. While armed (degradedPoll) and the window is open on a
-  // chat, poll POST /ai-chat/messages/delta every 2.5s: it returns only the rows
-  // CHANGED since the previous cursor (+ the run fact) in ONE round-trip. We merge
-  // those rows into the SAME infinite-query cache the thread reads (idempotently by
-  // id — the delta's overlap window re-delivers rows), so the thread's reconcile
-  // effect follows the detached run to its terminal row from a fraction of the wire
-  // cost. The run-fact settle stays the thread FSM's job (row-status reconcile), so
-  // we do NOT double-poll /run here. Cursor resets when the chat changes / disarms.
-  const deltaCursorRef = useRef<string | undefined>(undefined);
-  useEffect(() => {
-    deltaCursorRef.current = undefined;
-  }, [activeChatId, degradedPoll]);
-  useEffect(() => {
-    if (!degradedPoll || !windowOpen || !activeChatId) return;
-    const chatId = activeChatId;
-    let cancelled = false;
-    const tick = async (): Promise<void> => {
-      try {
-        const res = await getAiChatMessagesDelta(chatId, deltaCursorRef.current);
-        if (cancelled) return;
-        deltaCursorRef.current = res.cursor;
-        if (res.rows.length > 0) {
-          queryClient.setQueryData(
-            AI_CHAT_MESSAGES_RQ_KEY(chatId),
-            (
-              old:
-                | {
-                    pages: { items: IAiChatMessageRow[]; meta: unknown }[];
-                    pageParams: unknown[];
-                  }
-                | undefined,
-            ) =>
-              old
-                ? { ...old, pages: mergeDeltaRowsIntoPages(old.pages, res.rows) }
-                : old,
-          );
-        }
-      } catch {
-        // Transient failure (e.g. a server restart mid-run): swallow and retry on
-        // the next tick — the poll must survive a bounce, like the old dumb refetch.
-      }
-    };
-    const id = setInterval(() => void tick(), 2500);
-    return () => {
-      cancelled = true;
-      clearInterval(id);
-    };
-  }, [degradedPoll, windowOpen, activeChatId, queryClient]);
-
   // #184 reconnect-and-live-follow. Whether detached agent runs are enabled for
   // this workspace. When the feature is off no runs are ever created, so the
   // resume attempt would only ever 204; gating ChatThread's resume on it avoids a

apps/client/src/features/ai-chat/components/chat-thread.test.tsx

@@ -172,18 +172,9 @@ function resetState() {
   h.state.getRun.mockResolvedValue({ run: null, message: null });
 }
 
-// #491: the streaming tail carries a persisted step frontier (metadata.stepsPersisted),
-// which the tail-only attach reads as `n` in `?anchor=<id>&n=<n>`. Seeded WHOLE now.
 const streamingTail = () => [
   row("u1", "user", undefined, "hi"),
-  {
-    id: "a1",
-    role: "assistant",
-    content: "partial",
-    status: "streaming",
-    createdAt: "2026-01-01T00:00:00Z",
-    metadata: { stepsPersisted: 2 },
-  } as IAiChatMessageRow,
+  row("a1", "assistant", "streaming", "partial"),
 ];
 const settledTail = () => [
   row("u1", "user", undefined, "hi"),
@@ -344,24 +335,20 @@ describe("ChatThread — send now", () => {
     expect(screen.getAllByLabelText("Remove queued message")).toHaveLength(1);
   });
 
-  it("Stop then a REAL network-drop finish exits to idle (honor-in-stopping), NOT a false reconnect", async () => {
+  it("Stop then a REAL network-drop finish exits to idle (honor-in-stopping), NOT a false reconnect", () => {
     // Regression for the disconnect-first reorder: on the STOP path, even a drop-
     // form finish { isError:true, isDisconnect:true } arriving in `stopping` must be
     // HONORED (reducer) and exit to idle — it must NOT enter the reconnect ladder.
     startLocalStreamWithRun(); // live local stream, autonomous
     fireEvent.click(screen.getByLabelText("Stop")); // STOP_REQUESTED -> stopping
     h.state.error = { message: "Failed to fetch" };
-    // #491: the disconnect re-seeds from persist (async getRun) before dispatching
-    // FINISH_DISCONNECT, which the reducer HONORS in `stopping` -> idle. Flush it.
-    await act(async () => {
+    act(() => {
       h.state.onFinish?.({
         message: { id: "a1", role: "assistant", parts: [] },
         isAbort: false,
         isDisconnect: true,
         isError: true,
       });
-      await Promise.resolve();
-      await Promise.resolve();
     });
     expect(screen.queryByText(/reconnecting/i)).toBeNull();
   });
@@ -816,24 +803,19 @@ describe("ChatThread — resume (attach) machinery", () => {
     expect(h.state.resumeStream).not.toHaveBeenCalled();
   });
 
-  it("#491 tail-only: seeds the streaming tail WHOLE (no strip), keeps a user tail whole", () => {
+  it("strips the streaming tail from the seed, keeps a user tail whole", () => {
     renderThread({ autonomousRunsEnabled: true, initialRows: streamingTail() });
-    // MUTATION-VERIFY: re-introduce the seed-strip and this goes red — the streaming
-    // tail (steps 0..N-1) MUST be seeded so the SDK continuation appends the tail to
-    // the RIGHT message. Both rows (user + assistant) are seeded.
-    expect(h.state.seededMessages).toHaveLength(2);
+    expect(h.state.seededMessages).toHaveLength(1);
     cleanup();
     resetState();
     renderThread({ autonomousRunsEnabled: true, initialRows: userTail() });
     expect(h.state.seededMessages).toHaveLength(1);
   });
 
-  it("#491 tail-only: builds the attach URL with ?anchor=&n= from the persisted step frontier", () => {
+  it("builds the attach URL with expect=live&anchor only for a stripped streaming tail", () => {
     renderThread({ autonomousRunsEnabled: true, initialRows: streamingTail() });
-    // n=2 comes from a1's metadata.stepsPersisted (MUTATION-VERIFY: hardcode n=0 and
-    // this fails). No `expect=live` param anymore.
     expect(h.state.transport!.prepareReconnectToStreamRequest!().api).toBe(
-      "/api/ai-chat/runs/c1/stream?anchor=a1&n=2",
+      "/api/ai-chat/runs/c1/stream?expect=live&anchor=a1",
     );
     cleanup();
     resetState();
@@ -857,41 +839,39 @@ describe("ChatThread — resume (attach) machinery", () => {
     });
   }
 
-  it("204 on a streaming tail: NO restore (row kept) + invalidate + onResumeFallback(true)", async () => {
+  it("204 on a streaming tail: restore + invalidate + onResumeFallback(true)", async () => {
     const { onResumeFallback, invalidateSpy } = renderThread({
       autonomousRunsEnabled: true,
       initialRows: streamingTail(),
     });
     await attachFetch({ status: 204, ok: false });
-    // #491 tail-only: the anchor row was never stripped, so there is NOTHING to
-    // restore. MUTATION-VERIFY: re-add a restore setMessages here and it goes red.
-    expect(h.state.setMessages).not.toHaveBeenCalled();
+    expect(h.state.setMessages).toHaveBeenCalledTimes(1); // restore
     expect(invalidateSpy).toHaveBeenCalledWith({
       queryKey: ["ai-chat-messages", "c1"],
     });
     expect(onResumeFallback).toHaveBeenCalledWith(true);
   });
 
-  it("F7 restart-survival: a 500 attach failure arms the poll WITHOUT a restore", async () => {
+  it("F7 restart-survival: a 500 attach failure restores the row AND arms the poll", async () => {
     const { onResumeFallback, invalidateSpy } = renderThread({
       autonomousRunsEnabled: true,
       initialRows: streamingTail(),
     });
     await attachFetch({ status: 500, ok: false });
-    expect(h.state.setMessages).not.toHaveBeenCalled();
+    expect(h.state.setMessages).toHaveBeenCalledTimes(1);
     expect(invalidateSpy).toHaveBeenCalledWith({
       queryKey: ["ai-chat-messages", "c1"],
     });
     expect(onResumeFallback).toHaveBeenCalledWith(true);
   });
 
-  it("F7 restart-survival: a network throw arms the poll WITHOUT a restore", async () => {
+  it("F7 restart-survival: a network throw restores the row AND arms the poll", async () => {
     const { onResumeFallback, invalidateSpy } = renderThread({
       autonomousRunsEnabled: true,
       initialRows: streamingTail(),
     });
     await attachFetch(new Error("network down"), true);
-    expect(h.state.setMessages).not.toHaveBeenCalled();
+    expect(h.state.setMessages).toHaveBeenCalledTimes(1);
     expect(invalidateSpy).toHaveBeenCalledWith({
       queryKey: ["ai-chat-messages", "c1"],
     });
@@ -951,7 +931,7 @@ describe("ChatThread — resume (attach) machinery", () => {
     expect(h.state.sendMessage).not.toHaveBeenCalled();
   });
 
-  it("an empty resumed message (starved replay) arms the poll WITHOUT a restore", () => {
+  it("an empty resumed message (starved replay) restores the row AND arms the poll", () => {
     h.state.status = "ready";
     const { onResumeFallback } = renderThread({
       autonomousRunsEnabled: true,
@@ -967,9 +947,7 @@ describe("ChatThread — resume (attach) machinery", () => {
         isError: false,
       });
     });
-    // #491 tail-only: the seeded steps 0..N-1 are still on screen (the SDK
-    // continuation never wiped them), so there is nothing to restore — just poll.
-    expect(h.state.setMessages).not.toHaveBeenCalled();
+    expect(h.state.setMessages).toHaveBeenCalledTimes(1); // restore
     expect(onResumeFallback).toHaveBeenCalledWith(true); // arm
   });
 
@@ -1017,41 +995,24 @@ describe("ChatThread — live reconnect + stalled", () => {
     cleanup();
   });
 
-  // #491: the authoritative PERSISTED assistant row `getRun` projects on a local
-  // disconnect — the re-seed source. Its metadata.stepsPersisted becomes `n`.
-  const persistedAnchor = (steps = 3) => ({
-    run: { id: "run-1", status: "running" },
-    message: {
-      id: "a2",
-      role: "assistant",
-      content: "persisted 0..N-1",
-      status: "streaming",
-      createdAt: "2026-01-01T00:00:00Z",
-      metadata: { stepsPersisted: steps },
-    },
-  });
-
   // A REAL live SSE drop. ai@6.0.207 emits BOTH { isError:true, isDisconnect:true }
-  // for a network TypeError AND sets useChat `error`. #491: an autonomous local drop
-  // now RE-SEEDS from persist (async getRun) BEFORE entering the reconnect ladder, so
-  // this helper is async and flushes the getRun microtask before returning.
-  async function disconnect(message: unknown = liveMsg) {
+  // for a network TypeError AND sets useChat `error` — NOT the { isError:false,
+  // error:null } form the old tests fed. This is the form browser QA hit; with the
+  // buggy isError-first routing OR without the errorView render-gate these tests go
+  // red (a real drop surfaces the terminal error banner, masking the reconnect
+  // ladder). MUTATION-VERIFY of disconnect-first + the errorView phase-gate.
+  function disconnect(message: unknown = liveMsg) {
     h.state.error = { message: "Failed to fetch" }; // the SDK sets error on the drop
-    await act(async () => {
+    act(() => {
       h.state.onFinish?.({
         message,
         isAbort: false,
         isDisconnect: true,
         isError: true,
       });
-      // Flush the getRun().then re-seed + the deferred FINISH_DISCONNECT dispatch.
-      await Promise.resolve();
-      await Promise.resolve();
     });
   }
   function renderLive() {
-    // The persisted-anchor read the local disconnect performs to re-seed from persist.
-    h.state.getRun.mockResolvedValue(persistedAnchor());
     const view = renderThread({
       autonomousRunsEnabled: true,
       initialRows: settledTail(),
@@ -1071,80 +1032,35 @@ describe("ChatThread — live reconnect + stalled", () => {
     });
   }
 
-  it("#491: a live disconnect RE-SEEDS from persist, then backs off to reconnect with ?anchor=&n=", async () => {
+  it("a live disconnect starts a backoff reconnect (banner + resumeStream after backoff)", () => {
     renderLive();
-    await disconnect();
-    // The re-seed read the authoritative persisted row and replaced the live partial.
-    // MUTATION-VERIFY: skip the getRun re-seed (send `n` off the live message) and the
-    // n below no longer matches the PERSISTED stepsPersisted.
-    expect(h.state.getRun).toHaveBeenCalledWith("c1");
-    expect(h.state.setMessages).toHaveBeenCalled(); // re-seeded the store from persist
+    disconnect();
     expect(screen.getByText(/reconnecting/i)).toBeTruthy();
     expect(h.state.resumeStream).not.toHaveBeenCalled();
     advanceToAttempt(1);
     expect(h.state.resumeStream).toHaveBeenCalledTimes(1);
-    // n=3 is the PERSISTED row's stepsPersisted (from getRun), NOT the live store.
     expect(h.state.transport!.prepareReconnectToStreamRequest!().api).toBe(
-      "/api/ai-chat/runs/c1/stream?anchor=a2&n=3",
+      "/api/ai-chat/runs/c1/stream?expect=live&anchor=a2",
     );
   });
 
-  it("#491 regression (#137/#161 dup): getRun REJECT on a live disconnect drops the live partial + nulls the anchor", async () => {
-    // The re-seed source (getRun) FAILS — a flaky-network blip (SSE + getRun both
-    // fail, network recovers in ~1s). The OLD .catch just re-entered the ladder with
-    // NO re-seed and NO filter, so the reconnect could tail-apply the registry's
-    // frames onto the live partial that ALREADY has those steps -> duplicated text.
-    renderLive();
-    h.state.getRun.mockReset();
-    h.state.getRun.mockRejectedValue(new Error("network"));
-    await disconnect(); // live partial = liveMsg (id "a2")
-    expect(h.state.getRun).toHaveBeenCalledWith("c1");
-    // THE GUARANTEE: on the getRun failure the live partial (a2) is FILTERED from the
-    // store, so the reconnect can never tail-apply already-present steps onto it.
-    // MUTATION-VERIFY: revert the .catch fix (enterReconnect only, no filter) and no
-    // setMessages call removes a2 -> this reddens.
-    const removedLivePartial = (
-      h.state.setMessages as unknown as {
-        mock: { calls: [unknown][] };
-      }
-    ).mock.calls.some(([updater]) => {
-      if (typeof updater !== "function") return false;
-      const out = (updater as (p: { id: string }[]) => { id: string }[])([
-        { id: "a2" },
-        { id: "u1" },
-      ]);
-      return !out.some((m) => m.id === "a2");
-    });
-    expect(removedLivePartial).toBe(true);
-    expect(screen.getByText(/reconnecting/i)).toBeTruthy();
-    advanceToAttempt(1);
-    expect(h.state.resumeStream).toHaveBeenCalledTimes(1);
-    // Anchor was nulled -> replay-from-start (no params) / 204 -> poll; never a stale
-    // ?anchor=&n= over the live partial.
-    expect(h.state.transport!.prepareReconnectToStreamRequest!().api).toBe(
-      "/api/ai-chat/runs/c1/stream",
-    );
-  });
-
-  it("#488 (browser QA): the reconnect banner is SHOWN, not masked by the residual useChat error", async () => {
+  it("#488 (browser QA): the reconnect banner is SHOWN, not masked by the residual useChat error", () => {
     // The drop sets useChat `error` (real SDK), and the terminal errorView describes
     // it ("Lost connection to the server"). The FSM phase-gate must let the
     // `reconnecting` banner WIN over that residual error. MUTATION-VERIFY: revert the
     // errorView phase-gate (show errorView whenever error is set) and the terminal
     // banner masks "reconnecting…" -> red.
     renderLive();
-    await disconnect();
+    disconnect();
     expect(h.state.error).not.toBeNull(); // the SDK error IS set during recovery
     expect(screen.getByText(/reconnecting/i)).toBeTruthy();
     // The terminal "Lost connection… reload" banner must NOT be showing.
     expect(screen.queryByText(/reload and try again/i)).toBeNull();
   });
 
-  it("#488 commit 2: a disconnect BEFORE the first assistant frame reconnects with NO anchor", async () => {
+  it("#488 commit 2: a disconnect BEFORE the first assistant frame reconnects with NO anchor", () => {
     renderLive();
-    // No persisted assistant row for a pre-first-frame break -> no anchor.
-    h.state.getRun.mockResolvedValue({ run: null, message: null });
-    await disconnect(null); // no assistant message yet (pre-first-frame break)
+    disconnect(null); // no assistant message yet (pre-first-frame break)
     expect(screen.getByText(/reconnecting/i)).toBeTruthy();
     expect(
       screen.queryByText("Connection lost — the answer was interrupted."),
@@ -1158,7 +1074,7 @@ describe("ChatThread — live reconnect + stalled", () => {
 
   it("a live re-attach (2xx) clears the reconnect banner", async () => {
     renderLive();
-    await disconnect();
+    disconnect();
     advanceToAttempt(1);
     await reconnect({ status: 200, ok: true });
     expect(screen.queryByText(/reconnecting/i)).toBeNull();
@@ -1166,7 +1082,7 @@ describe("ChatThread — live reconnect + stalled", () => {
 
   it("a 204 arms the degraded poll and backs off to the next attempt", async () => {
     const { onResumeFallback } = renderLive();
-    await disconnect();
+    disconnect();
     advanceToAttempt(1);
     expect(h.state.resumeStream).toHaveBeenCalledTimes(1);
     await reconnect({ status: 204, ok: false });
@@ -1178,7 +1094,7 @@ describe("ChatThread — live reconnect + stalled", () => {
 
   it("exhausts the attempt limit into a manual Retry, which restarts the sequence", async () => {
     renderLive();
-    await disconnect();
+    disconnect();
     for (let n = 1; n <= 5; n++) {
       advanceToAttempt(n);
       expect(h.state.resumeStream).toHaveBeenCalledTimes(n);
@@ -1196,23 +1112,22 @@ describe("ChatThread — live reconnect + stalled", () => {
   it("#488 commit 3: two breaks in a row produce two reconnect cycles", async () => {
     renderLive();
     // First break -> reconnect -> re-attach live.
-    await disconnect();
+    disconnect();
     advanceToAttempt(1);
     expect(h.state.resumeStream).toHaveBeenCalledTimes(1);
     await reconnect({ status: 200, ok: true });
     expect(screen.queryByText(/reconnecting/i)).toBeNull();
-    // The re-attached observer (live-follow) stream drops AGAIN -> a SECOND reconnect
-    // cycle. #491: this too re-seeds from persist before re-attaching (never tail-
-    // applies over the live-follow partial).
-    await disconnect();
+    // The re-attached observer stream drops AGAIN -> a SECOND reconnect cycle
+    // (the old one-shot !wasResumed gate sent this to silent poll).
+    disconnect();
     expect(screen.getByText(/reconnecting/i)).toBeTruthy();
     advanceToAttempt(1);
     expect(h.state.resumeStream).toHaveBeenCalledTimes(2);
   });
 
-  it("does NOT reconnect when autonomous runs are disabled", async () => {
+  it("does NOT reconnect when autonomous runs are disabled", () => {
     renderThread({ autonomousRunsEnabled: false, initialRows: settledTail() });
-    await disconnect();
+    disconnect();
     expect(screen.queryByText(/reconnecting/i)).toBeNull();
     expect(
       screen.getByText("Connection lost — the answer was interrupted."),
@@ -1223,7 +1138,7 @@ describe("ChatThread — live reconnect + stalled", () => {
 
   it("#488 commit 4a: the poll idle cap surfaces a stalled banner + Retry (not silent)", async () => {
     renderLive();
-    await disconnect();
+    disconnect();
     advanceToAttempt(1);
     await reconnect({ status: 204, ok: false }); // arms the poll (reconnecting)
     // No activity for the whole idle cap -> stalled.

apps/client/src/features/ai-chat/components/chat-thread.tsx

@@ -42,7 +42,7 @@ import { assistantMessageHasVisibleContent } from "@/features/ai-chat/utils/mess
 import {
   isStreamingTail,
   isSettledAssistantTail,
-  stepsPersistedOf,
+  seedRows,
   mergeById,
 } from "@/features/ai-chat/utils/resume-helpers.ts";
 import { getRun } from "@/features/ai-chat/services/ai-chat-service.ts";
@@ -266,33 +266,25 @@ export default function ChatThread({
   // is NOT one of the lifecycle flags the FSM replaced.
   const mountedRef = useRef(true);
 
-  // attachStrategy DATA (behind the resumeStream effect; #491 tail-only, WITHOUT
-  // touching the FSM). The controller is effect-owned (aborted in cleanup, I5).
-  // `anchorRef` is the PERSISTED assistant row that pins the run (server invariant
-  // 6) and its persisted step frontier N: it feeds `?anchor=<id>&n=<stepsPersisted>`
-  // so the tail-only attach returns frames for steps >= N (the seed carries 0..N-1).
-  // It is NOT a "stripped" row — the seed keeps every row (tail-only replaces the
-  // old full-replay+strip). Null when there is no streaming/active tail to resume.
+  // attachStrategy DATA (behind the resumeStream effect; #491 swaps it to tail-only
+  // WITHOUT touching the FSM). The controller is effect-owned (aborted in cleanup,
+  // I5). `stripRef`/`strippedRowRef` are the current full-replay+strip anchor.
   const attachAbortRef = useRef<AbortController | null>(null);
-  const anchorRef = useRef<{ id: string; stepsPersisted: number } | null>(
-    (() => {
-      if (chatId === null || !isStreamingTail(initialRows ?? [])) return null;
-      const rows = initialRows ?? [];
-      const tail = rows[rows.length - 1];
-      return { id: tail.id, stepsPersisted: stepsPersistedOf(tail) };
-    })(),
+  const stripRef = useRef(chatId !== null && isStreamingTail(initialRows ?? []));
+  const strippedRowRef = useRef<IAiChatMessageRow | null>(
+    stripRef.current ? (initialRows ?? [])[initialRows!.length - 1] : null,
   );
   // Effect-owned backoff timers (not lifecycle flags): the reconnect ladder and the
   // stalled inactivity cap. Cleared by the cancelReconnect effect / the cap effect.
   const reconnectTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
   const idleCapTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
 
-  // #491 tail-only: seed EVERY persisted row unchanged (no strip). The streaming
-  // tail holds steps 0..N-1; the run-stream registry's tail (steps >= N) is APPENDED
-  // to it by the SDK continuation (readUIMessageStream({ message })), so it must be
-  // present in the store for the attach to continue the RIGHT message.
   const initialMessages = useMemo<UIMessage[]>(
-    () => (initialRows ?? []).map(rowToUiMessage),
+    () =>
+      seedRows(
+        initialRows ?? [],
+        stripRef.current && autonomousRunsEnabled === true,
+      ).map(rowToUiMessage),
     [initialRows],
   );
 
@@ -343,16 +335,21 @@ export default function ChatThread({
     (eff: RunEffect, epoch: number) => {
       switch (eff.type) {
         case "resumeStream": {
-          // The attach GET. Stamp the outcome's generation (I1). #491 tail-only: the
-          // store already holds EXACTLY the persisted steps 0..N-1 (the mount seed IS
-          // persist; a reconnect was re-seeded from persist BEFORE FINISH_DISCONNECT
-          // scheduled it — see the onFinish disconnect handler), so there is nothing
-          // to filter here: the SDK continues that seeded message, appending the tail
-          // (steps >= N) without duplicating the pre-drop partial step.
+          // The attach GET. Stamp the outcome's generation (I1). A reconnect
+          // attempt filters the pinned live row from the store first (the mount
+          // seed already stripped it), so the live replay's text-start rebuilds it
+          // without duplicating parts (#430).
           pendingAttachEpochRef.current = epoch;
           // The resumed stream's onFinish is stamped with THIS attach generation
           // (F1), so a superseded attempt's late finish is dropped.
           turnEpochRef.current = epoch;
+          if (machineRef.current.phase.name === "reconnecting") {
+            const anchor = strippedRowRef.current;
+            if (anchor)
+              setMessagesRef.current?.((prev) =>
+                prev.filter((m) => m.id !== anchor.id),
+              );
+          }
           void resumeStreamRef.current?.();
           break;
         }
@@ -467,23 +464,18 @@ export default function ChatThread({
       new DefaultChatTransport<UIMessage>({
         api: "/api/ai-chat/stream",
         credentials: "include",
-        prepareReconnectToStreamRequest: () => {
-          // #491 tail-only attach URL. When there is an anchor (a streaming/active
-          // tail to resume) build `?anchor=<assistantRowId>&n=<stepsPersisted>`: the
-          // server returns the TAIL — a synthetic `start` frame + frames for steps
-          // >= n, then live — which the SDK continuation appends to the seeded row.
-          // The server 204s (-> restore-noop + poll) when it cannot cover the
-          // frontier (overflow/rotation gap) or the anchor mismatches (a newer run).
-          // No anchor (a user tail / pre-first-frame break) => no params.
-          const anchor = anchorRef.current;
-          return {
-            api: `/api/ai-chat/runs/${chatIdRef.current}/stream${
-              anchor
-                ? `?anchor=${anchor.id}&n=${anchor.stepsPersisted}`
-                : ""
-            }`,
-          };
-        },
+        prepareReconnectToStreamRequest: () => ({
+          // Build the attach URL from the REAL chat id. ?expect=live&anchor=<row id>
+          // only when a streaming tail was stripped: expect=live opts into a
+          // finished-retained replay (safe only because the row is stripped and the
+          // replay rebuilds it), and the anchor pins the replay to OUR run — a
+          // mismatching (newer) run 204s into the restore+poll path instead.
+          api: `/api/ai-chat/runs/${chatIdRef.current}/stream${
+            stripRef.current
+              ? `?expect=live&anchor=${strippedRowRef.current!.id}`
+              : ""
+          }`,
+        }),
         fetch: async (input: RequestInfo | URL, init: RequestInit = {}) => {
           if ((init.method ?? "GET") !== "GET") {
             // Send path (POST). #488 commit 5: NO client 409 retry ladder anymore
@@ -570,9 +562,8 @@ export default function ChatThread({
 
   // Attach GET outcome -> FSM event. The epoch guard replaces BOTH the one-shot
   // 204 guard (noStreamHandledRef) and the unmount gate: a stale/superseded or
-  // post-DISPOSE outcome is dropped (I1). #491 tail-only: on a NONE outcome there is
-  // NOTHING to restore — the anchor row was never stripped from the view (the seed
-  // keeps it) — so we only invalidate for a fresh poll + dispatch the FSM event.
+  // post-DISPOSE outcome is dropped (I1). For a NONE outcome the attachStrategy
+  // recovery (restore the stripped row + invalidate for a fresh poll) runs first.
   const handleAttachOutcome = useCallback(
     (ep: number, wasReconnecting: boolean, live: boolean) => {
       if (ep !== epochRef.current) return; // stale generation — drop
@@ -584,6 +575,10 @@ export default function ChatThread({
         );
         return;
       }
+      if (strippedRowRef.current)
+        setMessagesRef.current?.((prev) =>
+          mergeById(prev, rowToUiMessage(strippedRowRef.current!)),
+        );
       queryClient.invalidateQueries({
         queryKey: AI_CHAT_MESSAGES_RQ_KEY(chatIdRef.current),
       });
@@ -666,124 +661,71 @@ export default function ChatThread({
       // keeps executing server-side — must win; only a NON-disconnect error (a
       // provider 500, `{ isError:true, isDisconnect:false }`) is terminal.
       if (isDisconnect) {
-        if (!mountedRef.current) {
+        if (wasObserver) {
+          // A resumed/attached OBSERVER stream dropped. Recover via the degraded
+          // poll (restore the stripped row only when there is no visible content;
+          // never clobber a fuller on-screen tail, invariant 9). The FSM decides
+          // reconnect-vs-poll from liveFollow (a live-follow drop reconnects again,
+          // #488 commit 3; a mount-resume drop polls).
+          if (mountedRef.current) {
+            const hasVisible = msgHasVisible;
+            if (!hasVisible && strippedRowRef.current)
+              setMessages((prev) =>
+                mergeById(prev, rowToUiMessage(strippedRowRef.current!)),
+              );
+            queryClient.invalidateQueries({
+              queryKey: AI_CHAT_MESSAGES_RQ_KEY(chatIdRef.current),
+            });
+            dispatch({
+              type: "FINISH_DISCONNECT",
+              hasVisibleContent: hasVisible,
+              epoch: stampEpoch,
+            });
+          }
           setStopNotice(null);
           return;
         }
-        // No detached run to recover (legacy, non-autonomous): a plain disconnect —
-        // terminal notice, no reconnect. (An observer only exists in autonomous mode,
-        // so this is always a local turn.)
-        if (autonomousRunsEnabled !== true) {
+        // A LOCAL live turn dropped. #488 commit 2: recover by the RUN-FACT, not by
+        // the presence of an assistant message — a setup-phase break (before the
+        // first frame) still leaves a detached run writing to pages. In autonomous
+        // mode a run is active for the whole turn, so seed the run-fact from the
+        // start-metadata runId when known, else a sentinel (the attach GET goes by
+        // chatId, not runId). Pin the assistant row as the strip/anchor when present.
+        if (autonomousRunsEnabled === true && mountedRef.current) {
+          const hasAnchor =
+            message?.role === "assistant" && typeof message.id === "string";
+          if (hasAnchor) {
+            strippedRowRef.current = {
+              id: message.id,
+              role: "assistant",
+              content: "",
+              status: "streaming",
+              createdAt: new Date().toISOString(),
+              metadata: { parts: message.parts },
+            };
+            stripRef.current = true;
+          } else {
+            strippedRowRef.current = null;
+            stripRef.current = false;
+          }
+          dispatch({
+            type: "RUN_FACT",
+            runFact: { runId: extractRunId(message) ?? "pending" },
+          });
+          dispatch({
+            type: "FINISH_DISCONNECT",
+            hasVisibleContent: msgHasVisible,
+            epoch: stampEpoch,
+          });
+          setStopNotice(null);
+        } else {
           dispatch({
             type: "FINISH_DISCONNECT",
             hasVisibleContent: false,
             epoch: stampEpoch,
           });
           setStopNotice("disconnect");
-          return;
         }
-        // A mount-resume OBSERVER (one-shot resume, NOT live-follow) drop falls to
-        // the degraded POLL, which merges by id — it does NOT attach, so there is
-        // nothing to re-seed. #491 tail-only: the anchor row was never removed from
-        // the view (the seed keeps it; the continuation only APPENDED), so nothing to
-        // restore either. The FSM routes this to `polling` (ownership observer,
-        // !liveFollow).
-        if (wasObserver && !machineRef.current.ctx.liveFollow) {
-          queryClient.invalidateQueries({
-            queryKey: AI_CHAT_MESSAGES_RQ_KEY(chatIdRef.current),
-          });
-          dispatch({
-            type: "FINISH_DISCONNECT",
-            hasVisibleContent: msgHasVisible,
-            epoch: stampEpoch,
-          });
-          setStopNotice(null);
-          return;
-        }
-        // We will (re-)ENTER THE RECONNECT LADDER (an attach): a LOCAL live turn's
-        // first drop, OR a live-follow observer's SUBSEQUENT drop (#488 commit 3).
-        // #488 commit 2: recover by the RUN-FACT, not by the presence of an assistant
-        // message — a setup-phase break still leaves a detached run writing to pages.
-        //
-        // #491 tail-only (THE crux): the live store holds a PARTIAL step that is AHEAD
-        // of the persisted boundary; tail-applying the reconnect's step frames over it
-        // would DUPLICATE that partial step. So entering reconnecting is ALWAYS via a
-        // RE-SEED FROM PERSIST — never the live store. Fetch the authoritative
-        // persisted assistant row (`getRun` returns the projected `message`), replace
-        // the live partial by id (mergeById -> the store now holds EXACTLY steps
-        // 0..N-1), and set the anchor to `{ id, n = stepsPersisted }`. Only AFTER the
-        // re-seed is applied do we enter the ladder (FINISH_DISCONNECT schedules the
-        // backoff) — so the attach can never tail-apply over the live partial.
-        const cid = chatIdRef.current;
-        // The live-message runId is the run-fact source (the attach GET keys on
-        // chatId, so a sentinel still recovers a setup-phase break).
-        const runId = extractRunId(message ?? undefined) ?? "pending";
-        const enterReconnect = (fact: string): void => {
-          if (!mountedRef.current) return;
-          // Epoch-stamp the run-fact too (I1): the getRun rtt widens the
-          // onFinish->dispatch window, so a concurrent SEND_LOCAL during it must be
-          // able to drop this stale RUN_FACT (else it clobbers the new turn's
-          // runFact.runId). Consistent with the postRun RUN_FACT stamp.
-          dispatch({ type: "RUN_FACT", runFact: { runId: fact }, epoch: stampEpoch });
-          dispatch({
-            type: "FINISH_DISCONNECT",
-            hasVisibleContent: msgHasVisible,
-            epoch: stampEpoch,
-          });
-        };
-        // Restore the STRUCTURAL guarantee that the live partial is never the
-        // tail-apply base: drop the live partial from the store by id and null the
-        // anchor, so the reconnect replays from step 0 into a CLEAN store (a full
-        // rebuild) or, past any rotation, 204s -> degraded poll. Used on BOTH the
-        // no-persisted-row and getRun-FAILURE paths — after this there is no path
-        // where the attach tail-applies frames onto a row that already has them
-        // (the #137/#161 duplication class).
-        const dropLivePartialAndReplayFromStart = (): void => {
-          if (message?.role === "assistant" && typeof message.id === "string") {
-            const liveId = message.id;
-            setMessagesRef.current?.((prev) =>
-              prev.filter((m) => m.id !== liveId),
-            );
-          }
-          anchorRef.current = null;
-        };
-        if (cid) {
-          void getRun(cid)
-            .then((res) => {
-              if (!mountedRef.current) return;
-              const persisted = res.message;
-              if (persisted && persisted.role === "assistant") {
-                anchorRef.current = {
-                  id: persisted.id,
-                  stepsPersisted: stepsPersistedOf(persisted),
-                };
-                // Replace the live partial with the persisted row IN PLACE by id —
-                // the re-seed from persist. The attach's tail (steps >= N) then
-                // appends to a store holding EXACTLY steps 0..N-1: no duplication.
-                setMessages((prev) => mergeById(prev, rowToUiMessage(persisted)));
-              } else {
-                // No persisted assistant row (pre-first-frame break): drop the live
-                // partial + replay from start (no anchor/n) so nothing is duplicated.
-                dropLivePartialAndReplayFromStart();
-              }
-              enterReconnect(res.run?.id ?? runId);
-            })
-            .catch(() => {
-              if (!mountedRef.current) return;
-              // Persist read FAILED: we cannot re-seed from fresh persist, and a
-              // stale mount-time anchor over the live partial would tail-apply
-              // already-present steps -> duplication (a flaky-network blip:
-              // SSE + getRun both fail, network recovers in ~1s, the registry still
-              // covers from the mount frontier). Restore the removed-filter guarantee
-              // instead: drop the live partial + replay from start / 204 -> poll.
-              dropLivePartialAndReplayFromStart();
-              enterReconnect(runId);
-            });
-        } else {
-          dropLivePartialAndReplayFromStart();
-          enterReconnect(runId);
-        }
-        setStopNotice(null);
         return;
       }
       // A NON-disconnect stream error (a provider 500 etc.) -> terminal error banner.
@@ -804,10 +746,11 @@ export default function ChatThread({
         if (mountedRef.current) {
           const hasVisible = msgHasVisible;
           if (!hasVisible) {
-            // Starved replay (the tail carried no new steps). #491 tail-only: the
-            // seeded steps 0..N-1 are still on screen (the SDK continuation never
-            // wiped them — `start` does not reset parts), so there is nothing to
-            // restore; just poll to the real terminal.
+            // Starved replay: restore the stripped row + poll to the real terminal.
+            if (strippedRowRef.current)
+              setMessages((prev) =>
+                mergeById(prev, rowToUiMessage(strippedRowRef.current!)),
+              );
             queryClient.invalidateQueries({
               queryKey: AI_CHAT_MESSAGES_RQ_KEY(chatIdRef.current),
             });
@@ -920,12 +863,12 @@ export default function ChatThread({
     const tail = rows[rows.length - 1];
     if (!tail || tail.role !== "assistant") return;
     setMessages((prev) => mergeById(prev, rowToUiMessage(tail)));
-    // Anchor-mismatch coherence: if a DIFFERENT run's row B has replaced our anchor
-    // row A as the tail, A would linger as an orphan — reconcile A by id from FRESH
-    // PERSISTED history (not the pinned live row) so no phantom row survives.
-    const anchor = anchorRef.current;
-    if (anchor && anchor.id !== tail.id) {
-      const historical = rows.find((r) => r.id === anchor.id);
+    // Anchor-mismatch coherence: a restored stripped row A that a DIFFERENT run's
+    // row B has replaced as the tail would linger as an orphan — settle A from
+    // fresh history so no phantom row survives.
+    const stripped = strippedRowRef.current;
+    if (stripped && stripped.id !== tail.id) {
+      const historical = rows.find((r) => r.id === stripped.id);
       if (historical)
         setMessages((prev) => mergeById(prev, rowToUiMessage(historical)));
     }

apps/client/src/features/ai-chat/services/ai-chat-service.ts

@@ -57,31 +57,6 @@ export async function stopRun(
   return req.data;
 }
 
-/**
- * Delta poll (#491): the chat's message rows changed since `cursor` (a DB-clock
- * timestamp echoed from the previous poll) plus the current run fact, in ONE
- * round-trip — the degraded-poll fallback's payload, replacing the old "refetch
- * ALL infinite-query pages every 2.5s with full parts" poll. Omit `cursor` on the
- * first poll (returns just a fresh cursor, no rows, to start the chain). The
- * overlap window guarantees occasional REPEATS, so the caller MUST merge rows
- * idempotently by id (mergeById). Owner-gated server-side.
- */
-export async function getAiChatMessagesDelta(
-  chatId: string,
-  cursor?: string,
-): Promise<{
-  rows: IAiChatMessageRow[];
-  cursor: string;
-  run: { id: string; status: string } | null;
-}> {
-  const req = await api.post<{
-    rows: IAiChatMessageRow[];
-    cursor: string;
-    run: { id: string; status: string } | null;
-  }>("/ai-chat/messages/delta", { chatId, cursor });
-  return req.data;
-}
-
 /**
  * #488: the run-fact — "is a run active on this chat?" — first-class from the
  * server (POST /ai-chat/run). Called on mount to seed the client FSM's run-fact

apps/client/src/features/ai-chat/state/run-fsm.spec.md

@@ -48,7 +48,6 @@ Legend: **†** = command-transition (bumps `epoch`, I1). Effects in `[…]`.
 | `RETRY` (manual, stalled banner) | stalled | polling(attach-none) **†** | `[armPoll]` |
 | `POLL_TERMINAL` (settled tail merged) | polling, reconnecting, stopping | idle | `[disarmPoll, cancelReconnect]`, runFact←null (I4) |
 | `POLL_IDLE_CAP` (inactivity cap) | polling, reconnecting | stalled | `[disarmPoll, cancelReconnect]` (commit 4a — no more silent) |
-| `POLL_IDLE_CAP` (inactivity cap) | stopping | idle | `[disarmPoll, cancelReconnect]`, runFact←null (Review #4: a Stop-armed poll with no SDK/terminal backstop gets a bounded exit — NOT `stalled`, Stop was already pressed so nothing to retry) |
 | `RUN_FACT{null}` (POST /run → null/terminal, 204) | reconnecting/attaching/polling/stopping | idle | `[cancelReconnect, disarmPoll]`, runFact←null (I3 fresh-negative gate) |
 | `RUN_FACT{runId}` | any | (same) | runFact←runId (pessimism toward an attempt) |
 | `STOP_REQUESTED` (user Stop) | streaming, reconnecting, polling | stopping **†** | `[stopRun, abortAttach, cancelReconnect, armPoll]` (poll drives the terminal — I4 exit by data) |
@@ -122,7 +121,8 @@ holds. **Pending column: empty.**
 | 11 | `stopPendingRef` | **FSM phase `stopping`** | the deferred stop fires from the chat-id adoption effect while `stopping` |
 | 12 | `mountedRef` | **retained (React liveness)** | orthogonal to run-lifecycle; gates imperative onFinish side-effects post-unmount. Epoch (I1) handles stale COMMAND-outcomes; DISPOSE bumps it |
 | 13 | `attemptResumeRef` | **FSM `ATTACH_START` + run-fact** | mount arms attach ONLY on a confirmed active run (commit 4b: streaming-tail status, or POST /run for a user tail) |
-| 14–15 | `anchorRef {id, stepsPersisted}` | **data** (attachStrategy) | #491 tail-only: replaced `stripRef`/`strippedRowRef`. The PERSISTED assistant row that pins the run (server invariant 6) + its step frontier N; feeds `?anchor=<id>&n=<stepsPersisted>`. No strip — the seed keeps every row; entering reconnecting re-seeds from persist |
+| 14 | `stripRef` | **data** (attachStrategy) | strip+replay detail; the `resumeStream` effect reads it |
+| 15 | `strippedRowRef` | **data** (attachStrategy) | the anchor row |
 | 16 | `attachAbortRef` | **effect-owned controller** | aborted by the `abortAttach` effect in cleanup (I5) |
 | 17–25 | `chatIdRef`, `openPageRef`, `getEditorSelectionRef`, `roleIdRef`, `stableIdRef`, `queuedRef`, `sendMessageRef`, `statusRef`, `lastForwardedChatIdRef` | **data** (identity/send mirrors) | unchanged — not lifecycle flags |
 | NEW | `pendingSupersedeRef` | **data** (send-plumbing) | the runId injected into the next `POST /stream {supersede}`; the single replacement for the 3 DELETED one-shots (#8/#9/#10) — net −2 refs |
@@ -151,12 +151,8 @@ message. Sources, in the order they update `ctx.runFact`:
 3. **Attach outcomes:** `ATTACH_LIVE` (2xx) confirms active; a 204 on a non-stripped
    path is an authoritative NEGATIVE fact → the runtime dispatches `RUN_FACT{null}`,
    which cancels recovery (I3 fresh-negative gate).
-4. **Poll (#491, implemented):** the degraded poll now hits the delta endpoint
-   (`POST /ai-chat/messages/delta`), which ALREADY carries the run fact
-   (`run: {id, status} | null`) alongside the changed rows. The client does NOT yet
-   consume that run field — it still drives to a terminal ROW (merged by id),
-   dispatched as `POLL_TERMINAL` — so the run field rides the wire for a future
-   client that settles straight off it.
+4. **Poll (future resume-stack iteration #491):** the delta will carry the run field;
+   until then the poll drives to a terminal ROW, dispatched as `POLL_TERMINAL`.
 
 Pessimism rule: a stale-but-positive fact PERMITS entering recovery (attach); the
 204 then cuts it. A fresh negative fact gates recovery OUT immediately.
@@ -182,9 +178,6 @@ Pessimism rule: a stale-but-positive fact PERMITS entering recovery (attach); th
   /run) are effect-owned and aborted in cleanup (`abortAttach` on `DISPOSE`), not
   render-phase refs. A client abort of an already-sent POST does not cancel the
   server action, so disarming on unmount is safe.
-- **attachStrategy** is behind the `resumeStream` effect; #491 swapped it to
-  tail-only (`?anchor=&n=`, `anchorRef` data) WITHOUT touching the FSM. Entering
-  reconnecting always re-seeds from persist; on a getRun failure the live partial
-  is dropped + replay-from-start so it is never the tail-apply base (no #137/#161
-  duplication).
+- **attachStrategy** (strip+replay today) is behind the `resumeStream` effect; the
+  resume-stack iteration (#491) swaps it to tail-only WITHOUT touching the FSM.
 - **Queue** stays a data structure; flush/interrupt decisions are transitions.

apps/client/src/features/ai-chat/types/ai-chat.types.ts

@@ -181,12 +181,6 @@ export interface IAiChatMessageRow {
   toolCalls?: unknown;
   metadata?: {
     parts?: UIMessage["parts"];
-    // #491 step-alignment anchor: the count of FINISHED steps whose parts are in
-    // THIS row, written atomically with `parts` server-side (flushAssistant). The
-    // resume client reads it as its persisted step frontier N — the tail-only
-    // attach asks the run-stream registry for the frames of step N onward (the
-    // seed already carries steps 0..N-1). Absent on pre-#491 rows -> read as 0.
-    stepsPersisted?: number;
     // AI SDK v6 `totalUsage` persisted on assistant rows. Legacy cumulative
     // figure (sum of every step's usage for the turn); kept for back-compat and
     // as the fallback for older rows that have no `contextTokens`.

apps/client/src/features/ai-chat/utils/count-stream-tokens.test.ts

@@ -6,13 +6,10 @@ describe("estimateTokens", () => {
     expect(estimateTokens("")).toBe(0);
   });
 
-  // #490: migrated onto the shared @docmost/token-estimate module (chars/2.5, up
-  // from the old client-only chars/4) so the client counter and the server replay
-  // budgeter can never diverge.
-  it("ceils chars/2.5 so any non-empty text is at least 1 token", () => {
+  it("ceils chars/4 so any non-empty text is at least 1 token", () => {
     expect(estimateTokens("a")).toBe(1);
-    expect(estimateTokens("ab")).toBe(1);
-    expect(estimateTokens("abcde")).toBe(2); // 5 / 2.5 = 2
-    expect(estimateTokens("x".repeat(10))).toBe(4); // 10 / 2.5 = 4
+    expect(estimateTokens("abcd")).toBe(1);
+    expect(estimateTokens("abcde")).toBe(2);
+    expect(estimateTokens("12345678")).toBe(2);
   });
 });

apps/client/src/features/ai-chat/utils/count-stream-tokens.ts

@@ -2,10 +2,18 @@
  * Rough client-side token estimation for AI-chat UI affordances.
  *
  * No provider streams exact per-token usage mid-stream, so any in-flight figure
- * is a CLIENT ESTIMATE. This re-exports the SHARED estimator from
- * `@docmost/token-estimate` (chars/2.5) so the in-body counter and the server's
- * replay budgeter use the SAME heuristic — two divergent estimators would mean
- * "the badge shows 60%" while "the budgeter already trimmed" (#490). Used by the
- * in-body reasoning counter ("Thinking · N tokens").
+ * is a CLIENT ESTIMATE (chars/≈4 heuristic). Pure + unit-testable: it never runs
+ * a real BPE tokenizer (that would be O(n²) on the hot path, bloat the bundle,
+ * and be wrong for Gemini/Ollama anyway). Used by the in-body reasoning counter
+ * ("Thinking · N tokens").
  */
-export { estimateTokens } from "@docmost/token-estimate";
+
+/**
+ * Rough token estimate for a piece of text using the standard chars/≈4 heuristic.
+ * Returns 0 for empty/whitespace-free-of-content input, and ceils so any
+ * non-empty text counts as at least one token.
+ */
+export function estimateTokens(text: string): number {
+  if (!text) return 0;
+  return Math.ceil(text.length / 4);
+}

apps/client/src/features/ai-chat/utils/resume-helpers.test.ts

@@ -4,8 +4,7 @@ import type { IAiChatMessageRow } from "@/features/ai-chat/types/ai-chat.types.t
 import {
   isStreamingTail,
   isSettledAssistantTail,
-  stepsPersistedOf,
-  mergeDeltaRowsIntoPages,
+  seedRows,
   mergeById,
 } from "./resume-helpers.ts";
 
@@ -13,18 +12,8 @@ function row(
   id: string,
   role: string,
   status?: string,
-  stepsPersisted?: number,
 ): IAiChatMessageRow {
-  return {
-    id,
-    role,
-    content: "",
-    status,
-    createdAt: "2026-01-01T00:00:00Z",
-    ...(stepsPersisted !== undefined
-      ? { metadata: { stepsPersisted } }
-      : {}),
-  };
+  return { id, role, content: "", status, createdAt: "2026-01-01T00:00:00Z" };
 }
 
 function makeMsg(id: string, text: string): UIMessage {
@@ -76,92 +65,23 @@ describe("isSettledAssistantTail", () => {
   });
 });
 
-describe("stepsPersistedOf", () => {
-  it("reads metadata.stepsPersisted", () => {
-    expect(stepsPersistedOf(row("a1", "assistant", "streaming", 3))).toBe(3);
-    expect(stepsPersistedOf(row("a1", "assistant", "streaming", 0))).toBe(0);
+describe("seedRows", () => {
+  const rows = [row("u1", "user"), row("a1", "assistant", "streaming")];
+
+  it("returns the rows unchanged when not stripping", () => {
+    expect(seedRows(rows, false)).toBe(rows);
   });
 
-  it("defaults to 0 for a pre-#491 row (absent), null/undefined, or a bad value", () => {
-    expect(stepsPersistedOf(row("a1", "assistant", "streaming"))).toBe(0);
-    expect(stepsPersistedOf(null)).toBe(0);
-    expect(stepsPersistedOf(undefined)).toBe(0);
-    expect(
-      stepsPersistedOf({
-        id: "a1",
-        role: "assistant",
-        content: "",
-        createdAt: "x",
-        metadata: { stepsPersisted: -2 },
-      }),
-    ).toBe(0);
+  it("drops the last row when stripping", () => {
+    const seeded = seedRows(rows, true);
+    expect(seeded).toHaveLength(1);
+    expect(seeded[0].id).toBe("u1");
   });
 
-  it("floors a non-integer count", () => {
-    expect(
-      stepsPersistedOf({
-        id: "a1",
-        role: "assistant",
-        content: "",
-        createdAt: "x",
-        metadata: { stepsPersisted: 2.9 },
-      }),
-    ).toBe(2);
-  });
-});
-
-describe("mergeDeltaRowsIntoPages", () => {
-  const pages = () => [
-    { items: [row("u1", "user"), row("a1", "assistant", "streaming", 1)], meta: {} },
-  ];
-
-  it("returns the pages unchanged for an empty delta", () => {
-    const p = pages();
-    expect(mergeDeltaRowsIntoPages(p, [])).toBe(p);
-  });
-
-  it("appends a genuinely new row to the last page in chronological order", () => {
-    const merged = mergeDeltaRowsIntoPages(pages(), [row("a2", "assistant", "streaming", 0)]);
-    expect(merged[0].items.map((i) => i.id)).toEqual(["u1", "a1", "a2"]);
-  });
-
-  it("replaces a grown row in place (per-step growth), never appends a duplicate", () => {
-    const merged = mergeDeltaRowsIntoPages(pages(), [
-      row("a1", "assistant", "streaming", 2),
-    ]);
-    expect(merged[0].items.map((i) => i.id)).toEqual(["u1", "a1"]);
-    // the in-place replacement carries the grown step frontier.
-    expect(stepsPersistedOf(merged[0].items[1])).toBe(2);
-  });
-
-  it("does not mutate the input pages", () => {
-    const input = pages();
-    const before = input[0].items.slice();
-    mergeDeltaRowsIntoPages(input, [row("a2", "assistant", "streaming", 0)]);
-    expect(input[0].items).toEqual(before); // untouched
-  });
-
-  // #491 CONTRACT: the delta overlap window re-delivers the same rows, so merging
-  // MUST be idempotent — applying a delta twice equals applying it once (no growth,
-  // no reorder). A regression re-introduces duplicate assistant bubbles per poll.
-  it("is idempotent: applying the same delta twice equals once", () => {
-    const delta = [
-      row("a1", "assistant", "streaming", 2), // grown existing row
-      row("a2", "assistant", "streaming", 0), // new row
-    ];
-    const once = mergeDeltaRowsIntoPages(pages(), delta);
-    const twice = mergeDeltaRowsIntoPages(once, delta);
-    const thrice = mergeDeltaRowsIntoPages(twice, delta);
-    expect(once[0].items.map((i) => i.id)).toEqual(["u1", "a1", "a2"]);
-    expect(twice[0].items.map((i) => i.id)).toEqual(["u1", "a1", "a2"]);
-    expect(twice).toEqual(once);
-    expect(thrice).toEqual(once);
-  });
-
-  it("seeds a first page when the cache is empty", () => {
-    const merged = mergeDeltaRowsIntoPages([], [row("u1", "user")]);
-    expect(merged).toHaveLength(1);
-    expect(merged[0].items.map((i) => i.id)).toEqual(["u1"]);
+  it("returns an empty list when stripping a single-row list", () => {
+    expect(seedRows([row("a1", "assistant", "streaming")], true)).toHaveLength(
+      0,
+    );
   });
 });
 
@@ -189,37 +109,4 @@ describe("mergeById", () => {
     expect(mergeById(prev, null)).toBe(prev);
     expect(mergeById(prev, undefined)).toBe(prev);
   });
-
-  // #491 CONTRACT: the delta poll's overlap window GUARANTEES the same row is
-  // re-delivered across close polls, so merging must be IDEMPOTENT by id — merging
-  // the same row (or an equal-length list of rows) twice must not duplicate or
-  // reorder. This is the property the whole delta-poll design leans on; a
-  // regression here would re-introduce duplicate assistant bubbles on every poll.
-  it("is idempotent by id: re-merging the same row does not duplicate or reorder", () => {
-    const seed = [makeMsg("u1", "hi"), makeMsg("a1", "step 1")];
-    const repeat = makeMsg("a1", "step 1"); // the SAME row the overlap re-delivers
-    const once = mergeById(seed, repeat);
-    const twice = mergeById(once, repeat);
-    const thrice = mergeById(twice, repeat);
-    // Length is stable (no growth), order is stable (user then assistant).
-    expect(once.map((m) => m.id)).toEqual(["u1", "a1"]);
-    expect(twice.map((m) => m.id)).toEqual(["u1", "a1"]);
-    expect(thrice.map((m) => m.id)).toEqual(["u1", "a1"]);
-    // The repeated merge converges: the row is replaced in place, never appended.
-    expect(twice[1]).toBe(repeat);
-  });
-
-  it("is idempotent across a batch of repeated + grown rows (delta re-delivery)", () => {
-    // A delta poll re-delivers a1 (unchanged) and a2 (grown one step). Applying the
-    // batch twice must equal applying it once — the poll can re-send either.
-    const start = [makeMsg("u1", "hi"), makeMsg("a1", "done")];
-    const batch = [makeMsg("a1", "done"), makeMsg("a2", "grown step 2")];
-    const apply = (list: typeof start) =>
-      batch.reduce((acc, row) => mergeById(acc, row), list);
-    const once = apply(start);
-    const twice = apply(once);
-    expect(once.map((m) => m.id)).toEqual(["u1", "a1", "a2"]);
-    expect(twice.map((m) => m.id)).toEqual(["u1", "a1", "a2"]);
-    expect(twice).toEqual(once);
-  });
 });

apps/client/src/features/ai-chat/utils/resume-helpers.ts

@@ -11,10 +11,9 @@ import type { IAiChatMessageRow } from "@/features/ai-chat/types/ai-chat.types.t
 
 /**
  * A STREAMING tail: the last persisted row is an assistant row still marked
- * `status === 'streaming'`. #491 (tail-only): such a tail is seeded UNCHANGED —
- * it carries the persisted steps 0..N-1 — and the run-stream registry's tail
- * (frames for steps >= N) is APPENDED to it by the SDK's `readUIMessageStream`
- * continuation. Only the presence of this tail decides WHETHER to attach.
+ * `status === 'streaming'`. Such a tail is stripped from the seed and rebuilt by
+ * the replay (`expect=live`), since the SDK's `text-start` always pushes a new
+ * part and replaying over a seeded in-progress row would duplicate its text.
  */
 export function isStreamingTail(rows: IAiChatMessageRow[]): boolean {
   const tail = rows[rows.length - 1];
@@ -33,61 +32,15 @@ export function isSettledAssistantTail(rows: IAiChatMessageRow[]): boolean {
 }
 
 /**
- * #491 tail-only anchor: the count of FINISHED steps whose parts are persisted in
- * THIS assistant row (`metadata.stepsPersisted`), written atomically with `parts`
- * server-side. The resume client reads it as its persisted step frontier N — the
- * tail-only attach asks the run-stream registry for the frames of step N onward
- * (the seed already carries steps 0..N-1). Absent on pre-#491 rows => 0.
+ * Seed rows for `useChat`: return the rows unchanged, or without the last row when
+ * `strip` is set (the streaming tail is stripped so the live replay rebuilds it
+ * without duplicating parts).
  */
-export function stepsPersistedOf(
-  row: IAiChatMessageRow | null | undefined,
-): number {
-  const n = row?.metadata?.stepsPersisted;
-  return typeof n === "number" && n >= 0 ? Math.floor(n) : 0;
-}
-
-/** One page of the messages infinite-query cache (`{ items, meta }`). */
-export interface IMessagePage {
-  items: IAiChatMessageRow[];
-  meta: unknown;
-}
-
-/**
- * #491 delta-poll merge: upsert the delta poll's `rows` into the messages
- * infinite-query page structure IDEMPOTENTLY by id. The delta endpoint's overlap
- * window GUARANTEES occasional REPEATS, so this MUST converge: a row already
- * present is REPLACED IN PLACE (per-step growth of an in-progress row), a new row
- * is APPENDED to the last page in chronological order (the server returns delta
- * rows oldest-first). Applying the same delta twice equals applying it once. Never
- * mutates the input pages (returns fresh page objects with cloned item arrays).
- */
-export function mergeDeltaRowsIntoPages(
-  pages: IMessagePage[],
+export function seedRows(
   rows: IAiChatMessageRow[],
-): IMessagePage[] {
-  if (rows.length === 0) return pages;
-  const next: IMessagePage[] = pages.map((p) => ({
-    ...p,
-    items: p.items.slice(),
-  }));
-  const locate = (id: string): [number, number] | null => {
-    for (let pi = 0; pi < next.length; pi++) {
-      const ii = next[pi].items.findIndex((it) => it.id === id);
-      if (ii !== -1) return [pi, ii];
-    }
-    return null;
-  };
-  for (const row of rows) {
-    const at = locate(row.id);
-    if (at) {
-      next[at[0]].items[at[1]] = row; // replace in place — idempotent by id
-    } else if (next.length > 0) {
-      next[next.length - 1].items.push(row); // append chronologically
-    } else {
-      next.push({ items: [row], meta: undefined });
-    }
-  }
-  return next;
+  strip: boolean,
+): IAiChatMessageRow[] {
+  return strip ? rows.slice(0, -1) : rows;
 }
 
 /**

apps/client/src/features/ai-chat/utils/sdk-continuation-tripwire.test.ts

@@ -1,83 +0,0 @@
-import { describe, it, expect } from "vitest";
-import { readUIMessageStream, type UIMessage } from "ai";
-import pkg from "../../../../package.json";
-
-/**
- * PIN-SPEC TRIP-WIRE (#491). The tail-only attach continuation relies on THREE
- * behaviors of `ai@6.0.207`, verified line-by-line in the issue. Without this
- * test, an `ai` bump could silently break attach (the client would append the
- * live tail to the wrong message, or duplicate a step):
- *
- *   1. `readUIMessageStream({ message })` CONTINUES the passed message — it does
- *      not start a fresh one — so the tail streamed after a re-seed is appended to
- *      the seeded assistant row (the same DB id).
- *   2. A `start` frame does NOT reset the existing message's parts (so the seeded
- *      steps 0..N-1 survive; the synthetic `start` the registry prepends only
- *      carries the run-fact metadata).
- *   3. Text parts do NOT cross a `finish-step` boundary — a new `text-start` after
- *      `finish-step` is a NEW part — so the reconstructed steps stay separated and
- *      the step frontier stays meaningful.
- *
- * If an `ai` upgrade changes any of these, this test fails LOUD instead of the
- * resume path silently corrupting.
- */
-describe("ai SDK continuation trip-wire (#491, tail-only attach)", () => {
-  it("is pinned to the exact ai version the continuation was verified against", () => {
-    // A caret/range bump is exactly what would silently break attach — require an
-    // exact pin. Bumping ai MUST re-verify the behavior asserted below, then this.
-    expect((pkg as { dependencies: Record<string, string> }).dependencies.ai).toBe(
-      "6.0.207",
-    );
-  });
-
-  it("continues the seeded message: start does not reset parts, the tail appends as new parts", async () => {
-    // A seeded assistant row with ONE finished step already reconstructed.
-    const seeded: UIMessage = {
-      id: "assistant-1",
-      role: "assistant",
-      parts: [
-        { type: "step-start" },
-        { type: "text", text: "STEP0", state: "done" },
-      ],
-    } as UIMessage;
-
-    // The tail the registry delivers on re-attach: a synthetic start (run-fact),
-    // then step 1's frames, then finish. As UI-message chunks (what the SSE frames
-    // decode to).
-    const chunks = [
-      { type: "start", messageMetadata: { runId: "r1", chatId: "c1" } },
-      { type: "start-step" },
-      { type: "text-start", id: "t1" },
-      { type: "text-delta", id: "t1", delta: "STEP1" },
-      { type: "text-end", id: "t1" },
-      { type: "finish-step" },
-      { type: "finish" },
-    ];
-    const stream = new ReadableStream({
-      start(c) {
-        for (const ch of chunks) c.enqueue(ch);
-        c.close();
-      },
-    });
-
-    let last: UIMessage | undefined;
-    for await (const msg of readUIMessageStream({ message: seeded, stream })) {
-      last = msg;
-    }
-
-    expect(last).toBeDefined();
-    // Same message id (continuation, not a fresh message).
-    expect(last!.id).toBe("assistant-1");
-    // The seeded step-0 parts SURVIVED the `start` frame, and step 1 was appended
-    // as SEPARATE parts (text did not cross the finish-step boundary).
-    const shape = last!.parts.map((p) => `${p.type}:${(p as { text?: string }).text ?? ""}`);
-    expect(shape).toEqual([
-      "step-start:",
-      "text:STEP0",
-      "step-start:",
-      "text:STEP1",
-    ]);
-    // The run-fact metadata from the synthetic start frame is applied.
-    expect(last!.metadata).toMatchObject({ runId: "r1", chatId: "c1" });
-  });
-});

apps/client/src/features/editor/atoms/editor-atoms.ts

@@ -3,11 +3,20 @@ import { atom } from "jotai";
 // import would drag the whole @tiptap/core engine into the eager graph of every
 // shell component that reads one of these atoms.
 import type { Editor } from "@tiptap/core";
+import type { HocuspocusProvider } from "@hocuspocus/provider";
 import { PageEditMode } from "@/features/user/types/user.types.ts";
 import type { DictationUnavailableReason } from "@/features/dictation/dictation-status";
 
 export const pageEditorAtom = atom<Editor | null>(null);
 
+// #370 — the active page's collab provider, published by the page editor so the
+// header menu can emit the "save-version" stateless signal (Cmd+S / button).
+// Null when the page is read-only / collab isn't connected. A typed initial
+// value (rather than an explicit generic) keeps jotai's overload resolution on
+// the writable PrimitiveAtom branch.
+const initialCollabProvider: HocuspocusProvider | null = null;
+export const collabProviderAtom = atom(initialCollabProvider);
+
 export const titleEditorAtom = atom<Editor | null>(null);
 
 export const readOnlyEditorAtom = atom<Editor | null>(null);

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

@@ -31,11 +31,18 @@ import { useAtom, useAtomValue, useSetAtom } from "jotai";
 import useCollaborationUrl from "@/features/editor/hooks/use-collaboration-url";
 import { currentUserAtom } from "@/features/user/atoms/current-user-atom";
 import {
+  collabProviderAtom,
   currentPageEditModeAtom,
   dictationAvailabilityAtom,
   pageEditorAtom,
   yjsConnectionStatusAtom,
 } from "@/features/editor/atoms/editor-atoms";
+import { notifications } from "@mantine/notifications";
+import {
+  VERSION_SAVED_MESSAGE_TYPE,
+  type VersionSavedMessage,
+  saveVersionPending,
+} from "@/features/page-history/version-messages";
 import { asideStateAtom } from "@/components/layouts/global/hooks/atoms/sidebar-atom";
 import {
   activeCommentIdAtom,
@@ -124,6 +131,7 @@ export default function PageEditor({
 
   const [currentUser] = useAtom(currentUserAtom);
   const [, setEditor] = useAtom(pageEditorAtom);
+  const setCollabProvider = useSetAtom(collabProviderAtom);
   const [, setAsideState] = useAtom(asideStateAtom);
   const [, setActiveCommentId] = useAtom(activeCommentIdAtom);
   const [showCommentPopup, setShowCommentPopup] = useAtom(showCommentPopupAtom);
@@ -181,6 +189,24 @@ export default function PageEditor({
       const onStatelessHandler = ({ payload }: onStatelessParameters) => {
         try {
           const message = JSON.parse(payload);
+          // #370 — a version was saved somewhere; live-refresh the history panel
+          // on every client. Only the client that pressed Save (tracked by the
+          // module-level flag) shows the confirmation toast.
+          if (message?.type === VERSION_SAVED_MESSAGE_TYPE) {
+            const versionMsg = message as VersionSavedMessage;
+            queryClient.invalidateQueries({
+              queryKey: ["page-history-list"],
+            });
+            if (saveVersionPending.current) {
+              saveVersionPending.current = false;
+              notifications.show({
+                message: versionMsg.alreadySaved
+                  ? t("Already saved as the latest version")
+                  : t("Version saved"),
+              });
+            }
+            return;
+          }
           if (message?.type !== "page.updated" || !message.updatedAt) return;
           const pageData = queryClient.getQueryData<IPage>(["pages", slugId]);
           if (pageData) {
@@ -238,12 +264,16 @@ export default function PageEditor({
 
       local.on("synced", onLocalSyncedHandler);
       providersRef.current = { socket, local, remote };
+      // #370 — publish the provider so the header menu can emit save-version.
+      setCollabProvider(remote);
       setProvidersReady(true);
     } else {
+      setCollabProvider(providersRef.current.remote);
       setProvidersReady(true);
     }
     // Only destroy on final unmount
     return () => {
+      setCollabProvider(null);
       providersRef.current?.socket.destroy();
       providersRef.current?.remote.destroy();
       providersRef.current?.local.destroy();

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

@@ -1,4 +1,11 @@
-import { Text, Group, UnstyledButton, Avatar, Tooltip } from "@mantine/core";
+import {
+  Text,
+  Group,
+  UnstyledButton,
+  Avatar,
+  Tooltip,
+  Badge,
+} from "@mantine/core";
 import { CustomAvatar } from "@/components/ui/custom-avatar.tsx";
 import { AgentAvatarStack } from "@/components/ui/agent-avatar-stack.tsx";
 import { formattedDate } from "@/lib/time";
@@ -7,36 +14,59 @@ import clsx from "clsx";
 import { IPageHistory } from "@/features/page-history/types/page.types";
 import { memo, useCallback } from "react";
 import { useSetAtom } from "jotai";
+import { useTranslation } from "react-i18next";
 import { historyAtoms } from "@/features/page-history/atoms/history-atoms.ts";
 
 const MAX_VISIBLE_AVATARS = 5;
 
+/**
+ * #370 — map a snapshot's intentionality tier to its badge. `version: true`
+ * marks the intentional points (manual / agent); autosaves (boundary / idle /
+ * legacy null) are non-versions and get dimmed in the list.
+ */
+type HistoryKindMeta = { labelKey: string; color: string; version: boolean };
+export function historyKindMeta(kind?: string | null): HistoryKindMeta {
+  switch (kind) {
+    case "manual":
+      return { labelKey: "Saved", color: "blue", version: true };
+    case "agent":
+      return { labelKey: "Agent version", color: "violet", version: true };
+    case "boundary":
+      return { labelKey: "Boundary", color: "gray", version: false };
+    default: // "idle" | null | undefined (legacy autosave)
+      return { labelKey: "Autosave", color: "gray", version: false };
+  }
+}
+
 interface HistoryItemProps {
   historyItem: IPageHistory;
-  index: number;
-  onSelect: (id: string, index: number) => void;
-  onHover?: (id: string, index: number) => void;
+  // The previous snapshot for diff/restore is resolved by id from the FULL list
+  // in the parent (resolvePrevSnapshotId), so the item only needs to report its
+  // own id — never a list index (which would be the filtered-view index).
+  onSelect: (id: string) => void;
+  onHover?: (id: string) => void;
   onHoverEnd?: () => void;
   isActive: boolean;
 }
 
 const HistoryItem = memo(function HistoryItem({
   historyItem,
-  index,
   onSelect,
   onHover,
   onHoverEnd,
   isActive,
 }: HistoryItemProps) {
   const setHistoryModalOpen = useSetAtom(historyAtoms);
+  const { t } = useTranslation();
+  const kindMeta = historyKindMeta(historyItem.kind);
 
   const handleClick = useCallback(() => {
-    onSelect(historyItem.id, index);
-  }, [onSelect, historyItem.id, index]);
+    onSelect(historyItem.id);
+  }, [onSelect, historyItem.id]);
 
   const handleMouseEnter = useCallback(() => {
-    onHover?.(historyItem.id, index);
-  }, [onHover, historyItem.id, index]);
+    onHover?.(historyItem.id);
+  }, [onHover, historyItem.id]);
 
   const contributors = historyItem.contributors;
   const hasContributors = contributors && contributors.length > 0;
@@ -49,8 +79,20 @@ const HistoryItem = memo(function HistoryItem({
       onMouseEnter={handleMouseEnter}
       onMouseLeave={onHoverEnd}
       className={clsx(classes.history, { [classes.active]: isActive })}
+      // #370 — dim autosnapshots so intentional versions stand out.
+      style={{ opacity: kindMeta.version ? 1 : 0.55 }}
     >
-      <Text size="sm">{formattedDate(new Date(historyItem.createdAt))}</Text>
+      <Group gap={6} wrap="nowrap" justify="space-between">
+        <Text size="sm">{formattedDate(new Date(historyItem.createdAt))}</Text>
+        <Badge
+          size="xs"
+          radius="sm"
+          variant={kindMeta.version ? "filled" : "light"}
+          color={kindMeta.color}
+        >
+          {t(kindMeta.labelKey)}
+        </Badge>
+      </Group>
 
       <Group gap={6} wrap="nowrap" mt={4}>
         {hasContributors ? (

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

@@ -2,14 +2,16 @@ import {
   usePageHistoryListQuery,
   prefetchPageHistory,
 } from "@/features/page-history/queries/page-history-query";
-import HistoryItem from "@/features/page-history/components/history-item";
+import HistoryItem, {
+  historyKindMeta,
+} from "@/features/page-history/components/history-item";
 import {
   activeHistoryIdAtom,
   activeHistoryPrevIdAtom,
   historyAtoms,
 } from "@/features/page-history/atoms/history-atoms";
 import { useAtom, useSetAtom } from "jotai";
-import { useCallback, useEffect, useMemo, useRef } from "react";
+import { useCallback, useEffect, useMemo, useRef, useState } from "react";
 import {
   Button,
   ScrollArea,
@@ -17,9 +19,12 @@ import {
   Divider,
   Loader,
   Center,
+  Switch,
+  Text,
 } from "@mantine/core";
 import { useTranslation } from "react-i18next";
 import { useHistoryRestore } from "@/features/page-history/hooks";
+import { resolvePrevSnapshotId } from "@/features/page-history/utils/resolve-prev-snapshot";
 
 const PREFETCH_DELAY_MS = 150;
 
@@ -47,6 +52,22 @@ function HistoryList({ pageId }: Props) {
     [pageHistoryData],
   );
 
+  // #370 — "only versions" filter: hide autosnapshots (idle/boundary/legacy
+  // null), keep only intentional points (manual/agent). Filtering is over the
+  // already-loaded pages; the diff/restore still targets the true previous
+  // snapshot, so items carry their index within the FULL list.
+  const [onlyVersions, setOnlyVersions] = useState(false);
+  // Reuse historyKindMeta().version — the SAME predicate the badge (HistoryItem)
+  // uses to mark intentional points — so the "Only versions" filter and the badge
+  // can never drift apart when a future intentional kind is added.
+  const visibleItems = useMemo(
+    () =>
+      onlyVersions
+        ? historyItems.filter((item) => historyKindMeta(item.kind).version)
+        : historyItems,
+    [historyItems, onlyVersions],
+  );
+
   const loadMoreRef = useRef<HTMLDivElement>(null);
   const prefetchTimeoutRef = useRef<ReturnType<typeof setTimeout> | null>(null);
 
@@ -60,11 +81,13 @@ function HistoryList({ pageId }: Props) {
   }, []);
 
   const handleHover = useCallback(
-    (historyId: string, index: number) => {
+    (historyId: string) => {
       clearPrefetchTimeout();
       prefetchTimeoutRef.current = setTimeout(() => {
         prefetchPageHistory(historyId);
-        const prevId = historyItems[index + 1]?.id;
+        // The true previous snapshot in the FULL list (not the previous visible
+        // one under the "only versions" filter).
+        const prevId = resolvePrevSnapshotId(historyItems, historyId);
         if (prevId) {
           prefetchPageHistory(prevId);
         }
@@ -78,9 +101,11 @@ function HistoryList({ pageId }: Props) {
   }, [clearPrefetchTimeout]);
 
   const handleSelect = useCallback(
-    (id: string, index: number) => {
+    (id: string) => {
       setActiveHistoryId(id);
-      setActiveHistoryPrevId(historyItems[index + 1]?.id ?? "");
+      // Baseline = true previous snapshot in the FULL list, so the "only
+      // versions" filter never diffs/restores against the wrong item.
+      setActiveHistoryPrevId(resolvePrevSnapshotId(historyItems, id));
     },
     [historyItems, setActiveHistoryId, setActiveHistoryPrevId],
   );
@@ -128,12 +153,27 @@ function HistoryList({ pageId }: Props) {
 
   return (
     <div>
+      <Group px="xs" py={6} justify="flex-end">
+        <Switch
+          size="xs"
+          checked={onlyVersions}
+          onChange={(e) => setOnlyVersions(e.currentTarget.checked)}
+          label={t("Only versions")}
+        />
+      </Group>
+
       <ScrollArea h={620} w="100%" type="scroll" scrollbarSize={5}>
-        {historyItems.map((historyItem, index) => (
+        {onlyVersions && visibleItems.length === 0 && (
+          <Center py="md">
+            <Text size="sm" c="dimmed">
+              {t("No saved versions yet.")}
+            </Text>
+          </Center>
+        )}
+        {visibleItems.map((historyItem) => (
           <HistoryItem
             key={historyItem.id}
             historyItem={historyItem}
-            index={index}
             onSelect={handleSelect}
             onHover={handleHover}
             onHoverEnd={clearPrefetchTimeout}

apps/client/src/features/page-history/types/page.types.ts

@@ -24,6 +24,10 @@ export interface IPageHistory {
   updatedAt: string;
   lastUpdatedBy: IPageHistoryUser;
   contributors?: IPageHistoryUser[];
+  // #370 — intentionality tier: 'manual'/'agent' are versions (intentional
+  // points), 'idle'/'boundary' are autosnapshots; null/undefined = legacy
+  // autosave. Derived server-side, drives the history badge + "versions" filter.
+  kind?: "manual" | "agent" | "idle" | "boundary" | null;
   // Provenance markers copied off the page row when the snapshot was saved.
   // `'agent'` marks a version written by the AI agent; `lastUpdatedAiChatId`
   // (when present) deep-links to the chat that produced the edit.

apps/client/src/features/page-history/utils/resolve-prev-snapshot.test.ts

@@ -0,0 +1,42 @@
+import { describe, it, expect } from "vitest";
+import { resolvePrevSnapshotId } from "./resolve-prev-snapshot";
+
+// #370 F4 — the risky client path: with the "only versions" filter active, diff
+// and restore must still baseline against the TRUE previous snapshot in the FULL
+// list, never the previous VISIBLE version (which would skip the autosnapshots
+// between two versions). These pin that the resolution is by FULL-list order.
+describe("resolvePrevSnapshotId", () => {
+  // Newest-first, as the history list stores it: a version, then two autosaves,
+  // then an older version.
+  const full = [
+    { id: "v2", kind: "manual" },
+    { id: "a2", kind: "idle" },
+    { id: "a1", kind: "boundary" },
+    { id: "v1", kind: "manual" },
+    { id: "a0", kind: null },
+  ];
+
+  it("returns the immediate FULL-list successor, not the previous visible version", () => {
+    // Selecting v2 while filtered to versions-only must baseline against a2 (the
+    // real chronological predecessor), NOT v1 (the previous visible version).
+    expect(resolvePrevSnapshotId(full, "v2")).toBe("a2");
+  });
+
+  it("resolves an autosnapshot's predecessor by full-list order", () => {
+    expect(resolvePrevSnapshotId(full, "a1")).toBe("v1");
+  });
+
+  it("returns '' for the oldest item (no predecessor)", () => {
+    expect(resolvePrevSnapshotId(full, "a0")).toBe("");
+  });
+
+  it("returns '' for an id not in the list", () => {
+    expect(resolvePrevSnapshotId(full, "missing")).toBe("");
+  });
+
+  it("does not depend on a filtered subset — same result whatever is visible", () => {
+    // The helper only ever sees the full list; a filtered view cannot change the
+    // baseline it computes.
+    expect(resolvePrevSnapshotId(full, "v1")).toBe("a0");
+  });
+});

apps/client/src/features/page-history/utils/resolve-prev-snapshot.ts

@@ -0,0 +1,22 @@
+/**
+ * #370 — resolve the TRUE previous snapshot for a history item.
+ *
+ * The history panel can be filtered to "only versions" (manual/agent), but diff
+ * and restore must always compare against the immediately-preceding snapshot in
+ * the FULL, unfiltered list — NOT the previous VISIBLE item. Comparing against
+ * the previous visible version would silently skip the autosnapshots between two
+ * versions and diff/restore the wrong baseline.
+ *
+ * Given the full (newest-first) list and an item id, this returns the id of the
+ * item right after it in the full list (its chronological predecessor), or "" if
+ * it is the oldest / not found. Pure and list-order-preserving so it can be unit
+ * tested without mounting the component.
+ */
+export function resolvePrevSnapshotId(
+  fullItems: ReadonlyArray<{ id: string }>,
+  id: string,
+): string {
+  const index = fullItems.findIndex((item) => item.id === id);
+  if (index === -1) return "";
+  return fullItems[index + 1]?.id ?? "";
+}

apps/client/src/features/page-history/version-messages.ts

@@ -0,0 +1,28 @@
+/**
+ * #370 — page-version stateless wire formats. Kept in one place so the client
+ * emitter (Save hotkey / button) and the client listener (page-editor) agree
+ * with the server (PersistenceExtension) on the message shapes.
+ */
+
+/** Client → server: "save a version now". The server derives the tier
+ * (manual/agent) from the signed connection actor, never from this payload. */
+export const SAVE_VERSION_MESSAGE_TYPE = "save-version";
+
+/** Server → all clients: a version was saved (or promoted / already existed). */
+export const VERSION_SAVED_MESSAGE_TYPE = "version.saved";
+
+export interface VersionSavedMessage {
+  type: typeof VERSION_SAVED_MESSAGE_TYPE;
+  historyId: string;
+  kind: "manual" | "agent";
+  /** True when the latest snapshot was already a manual version (a no-op save). */
+  alreadySaved: boolean;
+}
+
+/**
+ * Cross-component coordination flag so only the client that pressed Save shows
+ * the confirmation toast, while every other client silently refreshes its
+ * history panel on the broadcast. A module-level ref avoids stale-closure
+ * pitfalls in the editor's long-lived stateless handler.
+ */
+export const saveVersionPending = { current: false };

apps/client/src/features/page/components/header/page-header-menu.tsx

@@ -3,6 +3,7 @@ import {
   IconArrowRight,
   IconArrowsHorizontal,
   IconClockHour4,
+  IconDeviceFloppy,
   IconDots,
   IconEye,
   IconEyeOff,
@@ -17,7 +18,7 @@ import {
   IconTrash,
   IconWifiOff,
 } from "@tabler/icons-react";
-import React, { useEffect, useRef, useState } from "react";
+import React, { useCallback, useEffect, useRef, useState } from "react";
 import { useAsideTriggerProps } from "@/hooks/use-toggle-aside.tsx";
 import { useAtom, useAtomValue } from "jotai";
 import { historyAtoms } from "@/features/page-history/atoms/history-atoms.ts";
@@ -39,9 +40,14 @@ import { Trans, useTranslation } from "react-i18next";
 import ExportModal from "@/components/common/export-modal";
 import { convertProseMirrorToMarkdown } from "@docmost/prosemirror-markdown/browser";
 import {
+  collabProviderAtom,
   pageEditorAtom,
   yjsConnectionStatusAtom,
 } from "@/features/editor/atoms/editor-atoms.ts";
+import {
+  SAVE_VERSION_MESSAGE_TYPE,
+  saveVersionPending,
+} from "@/features/page-history/version-messages.ts";
 import { formattedDate } from "@/lib/time.ts";
 import { PageEditModeToggle } from "@/features/user/components/page-state-pref.tsx";
 import MovePageModal from "@/features/page/components/move-page-modal.tsx";
@@ -72,9 +78,34 @@ export default function PageHeaderMenu({ readOnly }: PageHeaderMenuProps) {
   });
   const isDeleted = !!page?.deletedAt;
   const [workspace] = useAtom(workspaceAtom);
+  const collabProvider = useAtomValue(collabProviderAtom);
   // Community public-sharing entry point (replaces the removed EE PageShareModal)
   const workspaceSharingDisabled = workspace?.settings?.sharing?.disabled === true;
 
+  // #370 — explicit "save a version" (Cmd+S / Save button). One path for the
+  // human; the server derives the tier from the signed actor. Readers can't save
+  // (the button is hidden and the collab connection is read-only server-side).
+  const handleSaveVersion = useCallback(() => {
+    if (readOnly || !collabProvider) return;
+    // Flag this client as the initiator so only it shows the confirmation toast;
+    // a safety timeout clears it if no broadcast comes back (e.g. offline).
+    saveVersionPending.current = true;
+    window.setTimeout(() => {
+      saveVersionPending.current = false;
+    }, 5000);
+    collabProvider.sendStateless(
+      JSON.stringify({ type: SAVE_VERSION_MESSAGE_TYPE }),
+    );
+  }, [readOnly, collabProvider]);
+
+  // mod+S must also block the browser's "Save page" dialog. `triggerOnContent-
+  // Editable` + empty ignore-list so it fires while typing in the editor/title.
+  useHotkeys(
+    [["mod+S", handleSaveVersion, { preventDefault: true }]],
+    [],
+    true,
+  );
+
   useHotkeys(
     [
       [
@@ -133,15 +164,16 @@ export default function PageHeaderMenu({ readOnly }: PageHeaderMenuProps) {
         </ActionIcon>
       </Tooltip>
 
-      <PageActionMenu readOnly={readOnly} />
+      <PageActionMenu readOnly={readOnly} onSaveVersion={handleSaveVersion} />
     </>
   );
 }
 
 interface PageActionMenuProps {
   readOnly?: boolean;
+  onSaveVersion?: () => void;
 }
-function PageActionMenu({ readOnly }: PageActionMenuProps) {
+function PageActionMenu({ readOnly, onSaveVersion }: PageActionMenuProps) {
   const { t } = useTranslation();
   const [, setHistoryModalOpen] = useAtom(historyAtoms);
   const clipboard = useClipboard({ timeout: 500 });
@@ -303,6 +335,20 @@ function PageActionMenu({ readOnly }: PageActionMenuProps) {
             </Group>
           </Menu.Item>
 
+          {!readOnly && (
+            <Menu.Item
+              leftSection={<IconDeviceFloppy size={16} />}
+              onClick={onSaveVersion}
+              rightSection={
+                <Text size="xs" c="dimmed">
+                  {t("Ctrl+S")}
+                </Text>
+              }
+            >
+              {t("Save version")}
+            </Menu.Item>
+          )}
+
           <Menu.Item
             leftSection={<IconHistory size={16} />}
             onClick={openHistoryModal}

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 && pnpm --filter @docmost/prosemirror-markdown build && pnpm --filter @docmost/token-estimate build",
+    "pretest": "pnpm --filter @docmost/editor-ext build && pnpm --filter @docmost/prosemirror-markdown build",
     "test": "jest",
     "test:int": "jest --config test/jest-integration.json",
     "test:watch": "jest --watch",
@@ -44,7 +44,6 @@
     "@docmost/mcp": "workspace:*",
     "@docmost/pdf-inspector": "1.9.6",
     "@docmost/prosemirror-markdown": "workspace:*",
-    "@docmost/token-estimate": "workspace:*",
     "@fastify/compress": "^9.0.0",
     "@fastify/cookie": "^11.0.2",
     "@fastify/multipart": "^10.0.0",
@@ -207,7 +206,6 @@
       "^@docmost/db/(.*)$": "<rootDir>/database/$1",
       "^@docmost/transactional/(.*)$": "<rootDir>/integrations/transactional/$1",
       "^@docmost/ee/(.*)$": "<rootDir>/ee/$1",
-      "^@docmost/token-estimate$": "<rootDir>/../../../packages/token-estimate/src/index.ts",
       "^src/(.*)$": "<rootDir>/$1",
       "^@tiptap/react$": "<rootDir>/../test/stubs/tiptap-react.js"
     }

apps/server/src/collaboration/constants.ts

@@ -1,10 +1,36 @@
-export const HISTORY_INTERVAL = 5 * 60 * 1000;
-export const HISTORY_FAST_INTERVAL = 60 * 1000;
-export const HISTORY_FAST_THRESHOLD = 5 * 60 * 1000;
-
 // #348 — debounce window for the per-page RAG re-embed job. Repeated saves
 // within this window collapse to a single delayed job (coalesced by a stable
 // jobId), so active editing does not pile up expensive re-embeds (external API
 // + page_embeddings rewrite, concurrency 1). The worker reads the CURRENT page
 // state at run time, so the last content within the window wins.
 export const EMBED_DEBOUNCE_MS = 30 * 1000;
+
+/**
+ * #370 — page-history intentionality tiers. Domain of `page_history.kind`.
+ *   - 'manual' / 'agent'  → Tier 1 versions (intentional points)
+ *   - 'idle' / 'boundary' → Tier 0 autosnapshots (safety net)
+ * A legacy `null` kind is treated as an autosave.
+ */
+export type PageHistoryKind = 'manual' | 'agent' | 'idle' | 'boundary';
+
+/**
+ * #370 — trailing idle-flush windows. A page's pending idle snapshot is
+ * re-armed on every store and fires this long after edits go quiet, so a burst
+ * of edits collapses into a single autosnapshot instead of one-per-store. Human
+ * sessions are noisier and less risky, so they flush less often than the agent.
+ */
+export const IDLE_INTERVAL_USER = 60 * 60 * 1000; // 60m
+export const IDLE_INTERVAL_AGENT = 15 * 60 * 1000; // 15m
+
+/**
+ * #370 — max-wait ceiling for the idle flush. Pure trailing debounce starves the
+ * safety net: hocuspocus stores at least every ~45s, so a CONTINUOUS editing
+ * session would re-arm the trailing timer forever and never take an idle
+ * snapshot until edits finally go quiet (up to IDLE_INTERVAL_USER = 60m). This
+ * ceiling bounds the actual wait from the FIRST edit of a burst, so an idle
+ * snapshot fires at least this often during a long unbroken session — restoring
+ * a recovery point cadence closer to the old heuristic without one-per-store
+ * noise. Mirrors hocuspocus's own maxDebounce idea.
+ */
+export const IDLE_MAX_WAIT_USER = 10 * 60 * 1000; // 10m
+export const IDLE_MAX_WAIT_AGENT = 5 * 60 * 1000; // 5m

apps/server/src/collaboration/extensions/compute-history-job.spec.ts

@@ -1,84 +1,93 @@
+import { computeHistoryJob, resolveSource } from './persistence.extension';
 import {
-  computeHistoryJob,
-  resolveSource,
-} from './persistence.extension';
-import {
-  HISTORY_FAST_INTERVAL,
-  HISTORY_FAST_THRESHOLD,
-  HISTORY_INTERVAL,
+  IDLE_INTERVAL_AGENT,
+  IDLE_INTERVAL_USER,
+  IDLE_MAX_WAIT_AGENT,
+  IDLE_MAX_WAIT_USER,
 } from '../constants';
 
-// A fixed clock + fixed createdAt make pageAge deterministic.
-const NOW = 1_700_000_000_000;
 const PAGE_ID = '550e8400-e29b-41d4-a716-446655440000';
 
-// Build a minimal page whose age (NOW - createdAt) is exactly `ageMs`.
-const pageAged = (ageMs: number) => ({
-  id: PAGE_ID,
-  createdAt: new Date(NOW - ageMs),
-});
+const page = { id: PAGE_ID };
 
-describe('computeHistoryJob', () => {
-  it('agent edit → delay MUST be 0 and job id is source-keyed', () => {
-    // INVARIANT (§15 H2 / persistence.extension): the agent delay MUST stay 0.
-    // The worker re-reads the page row at run time, so any non-zero delay risks
-    // snapshotting content a later human edit has already overwritten. This is
-    // the load-bearing assertion of this spec — do not relax it.
-    const { jobId, delay } = computeHistoryJob(pageAged(0), 'agent', NOW);
-    expect(delay).toBe(0);
-    expect(jobId).toBe(`${PAGE_ID}-agent`);
-  });
-
-  it('agent edit on an OLD page is still delay 0 (age never applies to agents)', () => {
-    // Even when the page is far older than the fast threshold, the agent path
-    // must short-circuit to 0 — age-based debounce is a human-only concern.
-    const { jobId, delay } = computeHistoryJob(
-      pageAged(HISTORY_FAST_THRESHOLD + 60_000),
-      'agent',
-      NOW,
-    );
-    expect(delay).toBe(0);
-    expect(jobId).toBe(`${PAGE_ID}-agent`);
-  });
-
-  it('human edit on a YOUNG page (age < threshold) → fast interval, bare job id', () => {
-    const { jobId, delay } = computeHistoryJob(
-      pageAged(HISTORY_FAST_THRESHOLD - 1),
-      'user',
-      NOW,
-    );
-    expect(delay).toBe(HISTORY_FAST_INTERVAL);
+describe('computeHistoryJob (#370 — shared trailing idle pipeline)', () => {
+  it('human edit → user idle window, bare page.id job', () => {
+    // Humans and the agent now share ONE idle job per page (jobId = page.id).
+    // The agent's old delay=0 fast path is GONE — intentional agent points now
+    // arrive via the explicit save-version signal, not a zero-delay snapshot.
+    const { jobId, delay } = computeHistoryJob(page, 'user');
+    expect(delay).toBe(IDLE_INTERVAL_USER);
     expect(jobId).toBe(PAGE_ID);
   });
 
-  it('human edit on an OLD page (age > threshold) → standard interval', () => {
-    const { jobId, delay } = computeHistoryJob(
-      pageAged(HISTORY_FAST_THRESHOLD + 1),
-      'user',
-      NOW,
-    );
-    expect(delay).toBe(HISTORY_INTERVAL);
+  it('agent edit → agent idle window (shorter), still the bare page.id job', () => {
+    const { jobId, delay } = computeHistoryJob(page, 'agent');
+    expect(delay).toBe(IDLE_INTERVAL_AGENT);
+    // No `-agent` suffix anymore: the agent joins the common idle pipeline.
     expect(jobId).toBe(PAGE_ID);
   });
 
-  it('boundary: pageAge EXACTLY === threshold takes the slow branch (the `<` is strict)', () => {
-    // Off-by-one guard: the condition is `pageAge < HISTORY_FAST_THRESHOLD`, so
-    // an age of exactly the threshold is NOT "fast" — it must use HISTORY_INTERVAL.
-    const { delay } = computeHistoryJob(
-      pageAged(HISTORY_FAST_THRESHOLD),
-      'user',
-      NOW,
-    );
-    expect(delay).toBe(HISTORY_INTERVAL);
+  it('agent flushes sooner than a human', () => {
+    expect(IDLE_INTERVAL_AGENT).toBeLessThan(IDLE_INTERVAL_USER);
   });
 
-  it('treats any non-"agent" source string as human', () => {
-    // resolveSource only ever yields 'agent' | 'user', but guard the contract:
-    // the agent branch keys strictly on === 'agent'.
-    const { jobId, delay } = computeHistoryJob(pageAged(0), 'user', NOW);
-    expect(delay).toBe(HISTORY_FAST_INTERVAL);
+  it('treats any non-"agent" source string as human (keys strictly on === agent)', () => {
+    const { jobId, delay } = computeHistoryJob(page, 'user');
+    expect(delay).toBe(IDLE_INTERVAL_USER);
     expect(jobId).toBe(PAGE_ID);
   });
+
+  // #370 review round-1 WARNING: the max-wait ceiling prevents autosnapshot
+  // starvation during a continuous editing session (the trailing timer would
+  // otherwise re-arm forever and never fire).
+  describe('max-wait ceiling', () => {
+    const T0 = 1_000_000; // arbitrary fixed epoch for deterministic tests
+
+    it('once a burst is armed, delay clamps to the remaining max-wait budget', () => {
+      // 1 minute into the burst the USER interval (60m) far exceeds the remaining
+      // max-wait budget (10m - 1m = 9m), so the delay is clamped DOWN to that
+      // remaining budget — the full interval is NOT used once a ceiling applies.
+      const { delay } = computeHistoryJob(page, 'user', T0, T0 + 60_000);
+      expect(delay).toBe(IDLE_MAX_WAIT_USER - 60_000);
+    });
+
+    it('never waits longer than the max-wait budget from the burst start', () => {
+      // A store arriving right at the ceiling → delay 0 (fire promptly).
+      const { delay } = computeHistoryJob(
+        page,
+        'user',
+        T0,
+        T0 + IDLE_MAX_WAIT_USER,
+      );
+      expect(delay).toBe(0);
+    });
+
+    it('past the ceiling never returns a negative delay', () => {
+      const { delay } = computeHistoryJob(
+        page,
+        'user',
+        T0,
+        T0 + IDLE_MAX_WAIT_USER + 5 * 60_000,
+      );
+      expect(delay).toBe(0);
+    });
+
+    it('the agent ceiling is shorter than the user ceiling', () => {
+      expect(IDLE_MAX_WAIT_AGENT).toBeLessThan(IDLE_MAX_WAIT_USER);
+      const { delay } = computeHistoryJob(
+        page,
+        'agent',
+        T0,
+        T0 + IDLE_MAX_WAIT_AGENT,
+      );
+      expect(delay).toBe(0);
+    });
+
+    it('without a burstStart there is no ceiling (backward-compatible)', () => {
+      expect(computeHistoryJob(page, 'user').delay).toBe(IDLE_INTERVAL_USER);
+      expect(computeHistoryJob(page, 'agent').delay).toBe(IDLE_INTERVAL_AGENT);
+    });
+  });
 });
 
 describe('resolveSource (truth table)', () => {

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

@@ -40,11 +40,12 @@ describe('PersistenceExtension.onStoreDocument — Approach-A boundary snapshot'
   let pageHistoryRepo: {
     saveHistory: jest.Mock;
     findPageLastHistory: jest.Mock;
+    updateHistoryKind: jest.Mock;
   };
   let aiQueue: { add: jest.Mock };
-  let historyQueue: { add: jest.Mock };
+  let historyQueue: { add: jest.Mock; remove: jest.Mock };
   let notificationQueue: { add: jest.Mock };
-  let collabHistory: { addContributors: jest.Mock };
+  let collabHistory: { addContributors: jest.Mock; popContributors: jest.Mock };
   let transclusionService: {
     syncPageTransclusions: jest.Mock;
     syncPageReferences: jest.Mock;
@@ -93,13 +94,22 @@ describe('PersistenceExtension.onStoreDocument — Approach-A boundary snapshot'
     pageHistoryRepo = {
       saveHistory: jest.fn().mockImplementation(async () => {
         callOrder.push('saveHistory');
+        return { id: 'history-1' };
       }),
       findPageLastHistory: jest.fn().mockResolvedValue(null),
+      updateHistoryKind: jest.fn().mockResolvedValue(undefined),
     };
     aiQueue = { add: jest.fn().mockResolvedValue(undefined) };
-    historyQueue = { add: jest.fn().mockResolvedValue(undefined) };
+    historyQueue = {
+      add: jest.fn().mockResolvedValue(undefined),
+      // #370 — enqueuePageHistory now removes any pending idle job before re-adding.
+      remove: jest.fn().mockResolvedValue(undefined),
+    };
     notificationQueue = { add: jest.fn().mockResolvedValue(undefined) };
-    collabHistory = { addContributors: jest.fn().mockResolvedValue(undefined) };
+    collabHistory = {
+      addContributors: jest.fn().mockResolvedValue(undefined),
+      popContributors: jest.fn().mockResolvedValue([]),
+    };
     transclusionService = {
       syncPageTransclusions: jest.fn().mockResolvedValue(undefined),
       syncPageReferences: jest.fn().mockResolvedValue(undefined),
@@ -165,6 +175,50 @@ describe('PersistenceExtension.onStoreDocument — Approach-A boundary snapshot'
     expect(pageRepo.updatePage.mock.calls[0][0].lastUpdatedSource).toBe('user');
   });
 
+  // #370 review round-1 SUGGESTION: the boundary was GENERALIZED from a
+  // user→agent special-case to ANY lastUpdatedSource transition. These pin the
+  // generalized behaviour it was rebuilt for.
+  describe('generalized boundary — any source transition', () => {
+    // Same persisted page but with an explicit prior source.
+    const pageWithPriorSource = (prior: string | null) => ({
+      ...persistedHumanPage('NEW CONTENT'),
+      lastUpdatedSource: prior,
+    });
+
+    it('agent→user transition fires the boundary (pins the prior agent revision)', async () => {
+      const document = ydocFor(doc('NEW CONTENT'));
+      pageRepo.findById.mockResolvedValue(pageWithPriorSource('agent'));
+      pageHistoryRepo.findPageLastHistory.mockResolvedValue(null);
+
+      await ext.onStoreDocument(buildData(document, 'user') as any);
+
+      expect(pageHistoryRepo.saveHistory).toHaveBeenCalledTimes(1);
+      expect(callOrder).toEqual(['saveHistory', 'updatePage']);
+      expect(pageRepo.updatePage.mock.calls[0][0].lastUpdatedSource).toBe('user');
+    });
+
+    it('git→user transition fires the boundary (git-sync overwrite is a source change)', async () => {
+      const document = ydocFor(doc('NEW CONTENT'));
+      pageRepo.findById.mockResolvedValue(pageWithPriorSource('git'));
+      pageHistoryRepo.findPageLastHistory.mockResolvedValue(null);
+
+      await ext.onStoreDocument(buildData(document, 'user') as any);
+
+      expect(pageHistoryRepo.saveHistory).toHaveBeenCalledTimes(1);
+      expect(callOrder).toEqual(['saveHistory', 'updatePage']);
+    });
+
+    it('a null prior source (first-ever edit) does NOT fire the boundary', async () => {
+      const document = ydocFor(doc('NEW CONTENT'));
+      pageRepo.findById.mockResolvedValue(pageWithPriorSource(null));
+
+      await ext.onStoreDocument(buildData(document, 'agent') as any);
+
+      expect(pageHistoryRepo.saveHistory).not.toHaveBeenCalled();
+      expect(pageRepo.updatePage).toHaveBeenCalledTimes(1);
+    });
+  });
+
   it('idempotency: unchanged content → no updatePage, no history, no queues', async () => {
     // The Y.Doc content equals the persisted content deeply → early skip.
     // A Y.Doc round-trip normalizes attrs (e.g. paragraph indent), so derive
@@ -479,4 +533,231 @@ describe('PersistenceExtension.onStoreDocument — Approach-A boundary snapshot'
     // Contributors keyed by the UUID so they match the PAGE_HISTORY job (page.id).
     expect(collabHistory.addContributors.mock.calls[0][0]).toBe(PAGE_ID);
   });
+
+  // #370 — explicit save-version (Cmd+S / agent save tool) over the stateless
+  // seam. The tier is derived from the SIGNED connection actor, the store path
+  // is reused, and promote-not-dup avoids duplicating heavy content rows.
+  describe('save-version (#370)', () => {
+    const emitSave = (document: any, actor: 'user' | 'agent') =>
+      ext.onStateless({
+        connection: {
+          readOnly: false,
+          context: { user: { id: USER_ID, name: 'Alice' }, actor },
+        } as any,
+        documentName: `page.${PAGE_ID}`,
+        document: document as any,
+        payload: JSON.stringify({ type: 'save-version' }),
+      } as any);
+
+    // findById returns a page whose content already equals the live doc, so the
+    // store path is a no-op and we isolate the versioning decision.
+    const pageMatchingDoc = (document: any) => ({
+      ...persistedHumanPage('IGNORED'),
+      content: TiptapTransformer.fromYdoc(document, 'default'),
+    });
+
+    it('human save with no prior snapshot → writes a manual version + broadcasts', async () => {
+      const document = ydocFor(doc('VERSION ME'));
+      pageRepo.findById.mockResolvedValue(pageMatchingDoc(document));
+      pageHistoryRepo.findPageLastHistory.mockResolvedValue(null);
+
+      await emitSave(document, 'user');
+
+      expect(pageHistoryRepo.saveHistory).toHaveBeenCalledTimes(1);
+      expect(pageHistoryRepo.saveHistory.mock.calls[0][1]).toEqual(
+        expect.objectContaining({ kind: 'manual' }),
+      );
+      // The pending idle autosnapshot is cancelled by the explicit version.
+      expect(historyQueue.remove).toHaveBeenCalledWith(PAGE_ID);
+      const msg = JSON.parse(
+        (document as any).broadcastStateless.mock.calls[(document as any).broadcastStateless.mock.calls.length - 1][0],
+      );
+      expect(msg).toMatchObject({
+        type: 'version.saved',
+        kind: 'manual',
+        alreadySaved: false,
+      });
+    });
+
+    it('agent save derives kind=agent from the signed actor', async () => {
+      const document = ydocFor(doc('AGENT VERSION'));
+      pageRepo.findById.mockResolvedValue(pageMatchingDoc(document));
+      pageHistoryRepo.findPageLastHistory.mockResolvedValue(null);
+
+      await emitSave(document, 'agent');
+
+      expect(pageHistoryRepo.saveHistory.mock.calls[pageHistoryRepo.saveHistory.mock.calls.length - 1][1]).toEqual(
+        expect.objectContaining({ kind: 'agent' }),
+      );
+    });
+
+    it('promote-not-dup: latest snapshot is an autosave with identical content → upgrades in place', async () => {
+      const document = ydocFor(doc('SAME'));
+      const page = pageMatchingDoc(document);
+      pageRepo.findById.mockResolvedValue(page);
+      pageHistoryRepo.findPageLastHistory.mockResolvedValue({
+        id: 'auto-1',
+        content: page.content,
+        kind: 'idle',
+      });
+
+      await emitSave(document, 'user');
+
+      // No heavy new content row — the existing autosave is promoted to manual.
+      expect(pageHistoryRepo.updateHistoryKind).toHaveBeenCalledWith(
+        'auto-1',
+        'manual',
+        expect.anything(),
+      );
+      expect(pageHistoryRepo.saveHistory).not.toHaveBeenCalled();
+      const msg = JSON.parse(
+        (document as any).broadcastStateless.mock.calls[(document as any).broadcastStateless.mock.calls.length - 1][0],
+      );
+      expect(msg).toMatchObject({ historyId: 'auto-1', alreadySaved: false });
+    });
+
+    it('no-op when the latest snapshot is already a manual version of this content', async () => {
+      const document = ydocFor(doc('ALREADY SAVED'));
+      const page = pageMatchingDoc(document);
+      pageRepo.findById.mockResolvedValue(page);
+      pageHistoryRepo.findPageLastHistory.mockResolvedValue({
+        id: 'ver-1',
+        content: page.content,
+        kind: 'manual',
+      });
+
+      await emitSave(document, 'user');
+
+      expect(pageHistoryRepo.updateHistoryKind).not.toHaveBeenCalled();
+      expect(pageHistoryRepo.saveHistory).not.toHaveBeenCalled();
+      const msg = JSON.parse(
+        (document as any).broadcastStateless.mock.calls[(document as any).broadcastStateless.mock.calls.length - 1][0],
+      );
+      expect(msg).toMatchObject({ alreadySaved: true, kind: 'manual' });
+    });
+
+    it('a read-only connection cannot save a version', async () => {
+      const document = ydocFor(doc('READER'));
+      pageRepo.findById.mockResolvedValue(pageMatchingDoc(document));
+
+      await ext.onStateless({
+        connection: {
+          readOnly: true,
+          context: { user: { id: USER_ID }, actor: 'user' },
+        } as any,
+        documentName: `page.${PAGE_ID}`,
+        document: document as any,
+        payload: JSON.stringify({ type: 'save-version' }),
+      } as any);
+
+      expect(pageHistoryRepo.saveHistory).not.toHaveBeenCalled();
+      expect(pageHistoryRepo.updateHistoryKind).not.toHaveBeenCalled();
+    });
+
+    // #370 F8-twin — a COMMIT abort (serialization/deadlock/conn-drop) rejects
+    // OUTSIDE the tx callback, AFTER the destructive popContributors (SPOP) and
+    // saveHistory ran but the INSERT rolled back. onStateless has no retry, so
+    // the outer catch MUST re-add (SADD) the popped set or attribution is lost
+    // irrecoverably. MUTATION: drop the outer catch → addContributors is never
+    // called → this reddens.
+    it('restores popped contributors when the commit aborts after the callback', async () => {
+      const document = ydocFor(doc('VERSION ME'));
+      pageRepo.findById.mockResolvedValue(pageMatchingDoc(document));
+      // No matching snapshot → fresh version branch → pops contributors.
+      pageHistoryRepo.findPageLastHistory.mockResolvedValue(null);
+      collabHistory.popContributors.mockResolvedValue(['u1', 'u2']);
+
+      // A db whose commit REJECTS after the callback body resolved: the SPOP and
+      // saveHistory already ran, then the tx aborts. onStoreDocument's flush uses
+      // the same db but its content matches (no-op branch) and its own retry loop
+      // swallows the throw, so only the versioning tx exercises the restore.
+      const commitFailingDb = {
+        transaction: () => ({
+          execute: async (fn: (trx: any) => Promise<any>) => {
+            await fn(trxStub);
+            throw new Error('commit aborted (serialization_failure)');
+          },
+        }),
+      };
+      const ext2 = new PersistenceExtension(
+        pageRepo as any,
+        pageHistoryRepo as any,
+        commitFailingDb as any,
+        aiQueue as any,
+        historyQueue as any,
+        notificationQueue as any,
+        collabHistory as any,
+        transclusionService as any,
+      );
+      jest.spyOn(ext2['logger'], 'debug').mockImplementation(() => undefined);
+      jest.spyOn(ext2['logger'], 'warn').mockImplementation(() => undefined);
+      jest.spyOn(ext2['logger'], 'error').mockImplementation(() => undefined);
+
+      await expect(
+        ext2.onStateless({
+          connection: {
+            readOnly: false,
+            context: { user: { id: USER_ID, name: 'Alice' }, actor: 'user' },
+          } as any,
+          documentName: `page.${PAGE_ID}`,
+          document: document as any,
+          payload: JSON.stringify({ type: 'save-version' }),
+        } as any),
+      ).rejects.toThrow();
+
+      // Attribution preserved: the popped set is SADD-restored, keyed by the page
+      // UUID it was popped under.
+      expect(collabHistory.addContributors).toHaveBeenCalledWith(PAGE_ID, [
+        'u1',
+        'u2',
+      ]);
+    });
+
+    // #370 #260 — for a `page.<slugId>` document the idle job is armed under the
+    // page UUID (computeHistoryJob's jobId = page.id), so the supersede-remove
+    // must target page.id, not the raw slugId doc-name id, or it silently misses.
+    it('cancels the superseded idle job by the page UUID for a slugId doc', async () => {
+      const SLUG = 'slug-1'; // persistedHumanPage.slugId
+      const document = ydocFor(doc('VERSION ME'));
+      pageRepo.findById.mockResolvedValue(pageMatchingDoc(document));
+      pageHistoryRepo.findPageLastHistory.mockResolvedValue(null);
+
+      await ext.onStateless({
+        connection: {
+          readOnly: false,
+          context: { user: { id: USER_ID, name: 'Alice' }, actor: 'user' },
+        } as any,
+        documentName: `page.${SLUG}`,
+        document: document as any,
+        payload: JSON.stringify({ type: 'save-version' }),
+      } as any);
+
+      // remove() keyed by the UUID (the real jobId), never the slugId.
+      expect(historyQueue.remove).toHaveBeenCalledWith(PAGE_ID);
+      expect(historyQueue.remove).not.toHaveBeenCalledWith(SLUG);
+    });
+  });
+
+  // #370 — the in-memory idle-burst marker must be dropped on doc unload (like
+  // its sibling per-document maps) or it grows unbounded for every page that was
+  // edited but never manually saved. MUTATION: drop the afterUnloadDocument
+  // delete → the entry survives → this reddens.
+  describe('idleBurstStart housekeeping', () => {
+    it('afterUnloadDocument clears the idle-burst marker armed by a store', async () => {
+      const document = ydocFor(doc('EDIT'));
+      pageRepo.findById.mockResolvedValue(persistedHumanPage('EDIT'));
+
+      await ext.onStoreDocument(buildData(document, 'user') as any);
+
+      const map = ext['idleBurstStart'] as Map<string, number>;
+      // Keyed by documentName (buildData uses `page.${PAGE_ID}`).
+      expect(map.has(`page.${PAGE_ID}`)).toBe(true);
+
+      await ext.afterUnloadDocument({
+        documentName: `page.${PAGE_ID}`,
+      } as any);
+
+      expect(map.has(`page.${PAGE_ID}`)).toBe(false);
+    });
+  });
 });

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

@@ -37,9 +37,11 @@ import { Page } from '@docmost/db/types/entity.types';
 import { CollabHistoryService } from '../services/collab-history.service';
 import {
   EMBED_DEBOUNCE_MS,
-  HISTORY_FAST_INTERVAL,
-  HISTORY_FAST_THRESHOLD,
-  HISTORY_INTERVAL,
+  IDLE_INTERVAL_AGENT,
+  IDLE_INTERVAL_USER,
+  IDLE_MAX_WAIT_AGENT,
+  IDLE_MAX_WAIT_USER,
+  PageHistoryKind,
 } from '../constants';
 import { TransclusionService } from '../../core/page/transclusion/transclusion.service';
 import {
@@ -56,6 +58,16 @@ import { hasTransclusionFamilyNodes } from '../../core/page/transclusion/utils/t
  */
 export const INTENTIONAL_CLEAR_MESSAGE_TYPE = 'intentional-clear';
 
+/**
+ * #370 — wire format of the client→server "save a version" signal. Sent by the
+ * human (Cmd+S / Save button) and by the agent's explicit save tool over the
+ * SAME stateless channel. The intentionality tier ('manual' vs 'agent') is
+ * derived SERVER-SIDE from the signed connection actor, never from this
+ * payload, so a version's type is unforgeable. The document is taken from the
+ * connection (not the payload), so the signal cannot be aimed at another page.
+ */
+export const SAVE_VERSION_MESSAGE_TYPE = 'save-version';
+
 /**
  * #251 — how long an intentional-clear signal stays "pending" before it is
  * ignored. The signal is set on the clearing keystroke but consumed by the
@@ -92,35 +104,39 @@ export function resolveSource(
 }
 
 /**
- * Compute the BullMQ job id + delay for a page-history snapshot job. Pure so
- * the data-loss-sensitive timing arithmetic is unit-testable; `now` is injected
- * (caller passes `Date.now()`) for determinism.
+ * #370 — compute the BullMQ job id + delay for a page's trailing idle-flush
+ * autosnapshot. Pure so the timing is unit-testable.
  *
- * - Agent edits: delay 0 and a source-keyed job id `${page.id}-agent`. The
- *   delay MUST stay 0 — the worker re-reads the page row at run time, so any
- *   delay risks reading content a later human edit has already overwritten
- *   (mis-tagged snapshot). 0 minimizes that window. The `-agent` suffix keeps
- *   the job from coalescing with the bare-page.id human job.
- * - Human edits: age-based debounce so rapid human edits coalesce into one
- *   snapshot; job id is the bare `page.id`.
- *
- * BullMQ forbids ':' in custom job ids (Redis key separator), so '-' is used;
- * page.id is a UUID, so `${page.id}-agent` cannot collide with a human job.
+ * Both humans and the agent now share ONE idle pipeline (the agent's old
+ * `delay=0` fast path is gone — intentional agent points arrive via the
+ * explicit save-version signal instead). The job id is the bare `page.id`, so a
+ * page has at most one pending idle job; the caller removes-and-re-adds it on
+ * every store to keep it debounced to the trailing edge of an edit burst. The
+ * window differs by source only: the agent flushes sooner than a human.
  */
 export function computeHistoryJob(
-  page: Pick<Page, 'id' | 'createdAt'>,
+  page: Pick<Page, 'id'>,
   source: string,
-  now: number,
+  // Epoch ms of the FIRST edit in the current burst (when the pending idle job
+  // was first armed). Used to enforce the max-wait ceiling so a continuous
+  // editing session cannot re-arm the trailing timer forever. `now` is injectable
+  // for tests; both default to a live clock / no ceiling when omitted.
+  burstStart?: number,
+  now: number = Date.now(),
 ): { jobId: string; delay: number } {
   const isAgent = source === 'agent';
-  const pageAge = now - new Date(page.createdAt).getTime();
-  const delay = isAgent
-    ? 0
-    : pageAge < HISTORY_FAST_THRESHOLD
-      ? HISTORY_FAST_INTERVAL
-      : HISTORY_INTERVAL;
-  const jobId = isAgent ? `${page.id}-agent` : page.id;
-  return { jobId, delay };
+  const interval = isAgent ? IDLE_INTERVAL_AGENT : IDLE_INTERVAL_USER;
+  const maxWait = isAgent ? IDLE_MAX_WAIT_AGENT : IDLE_MAX_WAIT_USER;
+
+  let delay = interval;
+  if (burstStart !== undefined) {
+    // Time already elapsed since the burst's first edit; the snapshot must fire
+    // no later than `maxWait` after that, so shrink the trailing delay to the
+    // remaining budget (never negative, so BullMQ fires it promptly).
+    const remaining = burstStart + maxWait - now;
+    delay = Math.max(0, Math.min(interval, remaining));
+  }
+  return { jobId: page.id, delay };
 }
 
 @Injectable()
@@ -132,6 +148,28 @@ export class PersistenceExtension implements Extension {
   // coalescing window" per document and OR it across all edits in the window,
   // so the snapshot is marked 'agent' regardless of who wrote last.
   private agentTouched: Map<string, boolean> = new Map();
+  // #370 — epoch ms of the FIRST edit in the current idle-flush burst. Keyed by
+  // documentName (like its sibling per-document maps above), NOT by page.id, so
+  // it can be cleaned in afterUnloadDocument alongside `contributors` /
+  // `agentTouched` / `intentionalClear` when the doc unloads — otherwise any page
+  // that was edited but never manually saved (the common case) would keep its
+  // entry forever and the Map would grow unbounded in this long-lived process.
+  // Set when the pending idle job is first armed (empty entry), read to enforce
+  // the max-wait ceiling in computeHistoryJob, and cleared on doc unload or when
+  // a manual save cancels the idle job so the next burst starts a fresh window.
+  //
+  // Single-process assumption (like `contributors` / `agentTouched` above): this
+  // lives only in THIS collab process's memory. A restart, or a page's ownership
+  // moving to another node, loses the burst-start marker. Consequence: a burst
+  // that spans the restart looks like a fresh burst to the surviving process, so
+  // its max-wait ceiling is re-anchored to the first post-restart edit — a single
+  // continuous session straddling a restart can therefore wait up to ~2× the cap
+  // for its idle snapshot (once for the lost pre-restart window, once for the new
+  // one). Bounded and benign (it only DELAYS a safety-net autosnapshot; manual
+  // saves are unaffected and the next quiet period always flushes), but the
+  // assumption and its consequence are recorded here so no one mistakes the
+  // in-memory marker for a durable, cross-process guarantee.
+  private idleBurstStart: Map<string, number> = new Map();
   // #251 — per-document "intentional clear pending" flags. Keyed by
   // documentName, value = expiry timestamp (ms). Set by onStateless when the
   // client reports a deliberate clear; consumed once by the next
@@ -363,20 +401,19 @@ 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).
+          // #370 — boundary snapshot on ANY source transition. When the store
+          // flips the page's provenance (user↔agent↔git), pin the OUTGOING
+          // state as its own history version BEFORE the incoming source
+          // overwrites it. `page` still holds the OLD content/provenance here,
+          // so saveHistory(page) captures the pre-transition state tagged with
+          // its own source, kind='boundary'. The incoming content is snapshotted
+          // later by the debounced idle job. Skip if the page is effectively
+          // empty or if the latest existing snapshot already equals this state
+          // (the shared isDeepStrictEqual gate — avoids duplicates). Generalizing
+          // beyond the old user→agent special-case also covers git-sync for free.
           if (
-            lastUpdatedSource === 'agent' &&
-            page.lastUpdatedSource !== 'agent'
+            page.lastUpdatedSource &&
+            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).
@@ -384,15 +421,13 @@ export class PersistenceExtension implements Extension {
               page.id,
               { includeContent: true, trx },
             );
-            const humanBaselineMissing =
+            const baselineMissing =
               !lastHistory ||
               !isDeepStrictEqual(lastHistory.content, page.content);
-            if (
-              !isEmptyParagraphDoc(page.content as any) &&
-              humanBaselineMissing
-            ) {
+            if (!isEmptyParagraphDoc(page.content as any) && baselineMissing) {
               await this.pageHistoryRepo.saveHistory(page, {
                 contributorIds: page.contributorIds ?? undefined,
+                kind: 'boundary',
                 trx,
               });
             }
@@ -522,7 +557,7 @@ export class PersistenceExtension implements Extension {
         { jobId: `embed-${page.id}`, delay: EMBED_DEBOUNCE_MS },
       );
 
-      await this.enqueuePageHistory(page, lastUpdatedSource);
+      await this.enqueuePageHistory(page, documentName, lastUpdatedSource);
     }
 
     // #402 — report the serialized size for the store histogram's size_bucket.
@@ -554,6 +589,14 @@ export class PersistenceExtension implements Extension {
       return; // unrelated / malformed stateless message
     }
 
+    // #370 — explicit "save a version" (human Cmd+S / agent save tool). Edit
+    // rights are already enforced by the readOnly reject above (a reader can't
+    // create a version), exactly as intentional-clear requires.
+    if (message?.type === SAVE_VERSION_MESSAGE_TYPE) {
+      await this.handleSaveVersion(data);
+      return;
+    }
+
     if (message?.type !== INTENTIONAL_CLEAR_MESSAGE_TYPE) return;
 
     this.intentionalClear.set(
@@ -562,6 +605,160 @@ export class PersistenceExtension implements Extension {
     );
   }
 
+  /**
+   * #370 — persist an intentional version from the live in-memory ydoc.
+   *
+   * One stateless path serves BOTH the human and the agent; the tier is derived
+   * SERVER-SIDE from the signed connection actor ('agent' → 'agent', anything
+   * else → 'manual'), so the version type cannot be spoofed by the client. We
+   * take the fresh ydoc from the collab process memory and run it through the
+   * EXISTING store path first (so pages.content/ydoc reflect the exact content
+   * being versioned — a REST endpoint would race the up-to-10s-stale page row),
+   * then snapshot it into page_history with the intentional kind.
+   *
+   * Promote-not-dup: if the latest history row already holds this exact content
+   * and it is an autosave (idle/boundary/legacy-null), upgrade its kind in place
+   * instead of duplicating a heavy content row; if it is already 'manual', it is
+   * a no-op (the client shows an "already saved" toast). Otherwise a fresh
+   * version row is written, popping the aggregated contributors from Redis.
+   */
+  private async handleSaveVersion(data: onStatelessPayload): Promise<void> {
+    const { connection, document, documentName } = data;
+    const context = connection?.context;
+    const pageId = getPageId(documentName);
+    // Unforgeable: 'agent' only for a signed agent connection, else 'manual'.
+    const kind: PageHistoryKind =
+      context?.actor === 'agent' ? 'agent' : 'manual';
+
+    // Flush the live ydoc through the normal store path so the page row + ydoc
+    // hold exactly what we are about to version (also fires the idle enqueue we
+    // supersede below, plus any source-transition boundary). onStoreDocument
+    // only needs document/documentName/context.
+    await this.onStoreDocument({
+      document,
+      documentName,
+      context,
+    } as onStoreDocumentPayload);
+
+    let result:
+      | { historyId: string; kind: PageHistoryKind; alreadySaved: boolean }
+      | undefined;
+
+    // #370 F8-twin — the contributor set popped from Redis (destructive SPOP)
+    // must be restored if the version row does not durably land. The inner
+    // try/catch below only covers a throw INSIDE the callback; but executeTx
+    // COMMITS after the callback, so a commit-abort (serialization/deadlock/
+    // connection drop — the transient class the epic retries in the processor)
+    // rejects OUTSIDE the callback, after saveHistory already ran and the SPOP
+    // already happened, while the INSERT rolls back. onStateless does NOT retry,
+    // so an unrestored pop is a one-shot irrecoverable attribution loss (the
+    // processor got exactly this fix: poppedForRestore + an outer catch). We
+    // track the popped set here (keyed by the page UUID it was popped by — never
+    // the doc-name id, which may be a slugId, #260) and restore it in the outer
+    // catch. addContributors is an idempotent Redis SADD, so a double-restore is
+    // harmless. versionedPageId is also reused below to remove the superseded
+    // idle job by its real jobId (page.id).
+    let poppedForRestore: string[] = [];
+    let versionedPageId: string | undefined;
+
+    try {
+      await executeTx(this.db, async (trx) => {
+        const page = await this.pageRepo.findById(pageId, {
+          withLock: true,
+          includeContent: true,
+          trx,
+        });
+        if (!page) return;
+        versionedPageId = page.id;
+        // Never version an effectively-empty page (mirrors the processor's
+        // first-history guard); there is nothing intentional to pin.
+        if (isEmptyParagraphDoc(page.content as any)) return;
+
+        const lastHistory = await this.pageHistoryRepo.findPageLastHistory(
+          page.id,
+          { includeContent: true, trx },
+        );
+
+        if (
+          lastHistory &&
+          isDeepStrictEqual(lastHistory.content, page.content)
+        ) {
+          // Content is already snapshotted. Promote-not-dup.
+          if (lastHistory.kind === 'manual') {
+            result = {
+              historyId: lastHistory.id,
+              kind: 'manual',
+              alreadySaved: true,
+            };
+            return;
+          }
+          await this.pageHistoryRepo.updateHistoryKind(
+            lastHistory.id,
+            kind,
+            trx,
+          );
+          result = { historyId: lastHistory.id, kind, alreadySaved: false };
+          return;
+        }
+
+        // Fresh version row. Pop the contributors aggregated since the last
+        // snapshot (SPOP); restore them if the write fails so they aren't lost.
+        const contributorIds = await this.collabHistory.popContributors(
+          page.id,
+        );
+        poppedForRestore = contributorIds;
+        try {
+          const saved = await this.pageHistoryRepo.saveHistory(page, {
+            contributorIds,
+            kind,
+            trx,
+          });
+          result = { historyId: saved.id, kind, alreadySaved: false };
+        } catch (err) {
+          await this.collabHistory.addContributors(page.id, contributorIds);
+          poppedForRestore = [];
+          throw err;
+        }
+      });
+    } catch (err) {
+      // A throw here means the tx did NOT commit (callback threw, or the commit
+      // itself failed and rolled back). If we popped contributors and the inner
+      // catch did not already restore them, restore now so attribution is not
+      // lost — onStateless has no retry to recover it. Restore by the page UUID
+      // the pop was keyed under (versionedPageId is always set before the pop).
+      if (poppedForRestore.length && versionedPageId) {
+        await this.collabHistory.addContributors(
+          versionedPageId,
+          poppedForRestore,
+        );
+      }
+      throw err;
+    }
+
+    // Housekeeping: this explicit version supersedes the page's pending idle
+    // autosnapshot, so cancel it and end the current idle burst so the next edit
+    // starts a fresh max-wait window. Remove the idle job by its REAL jobId
+    // (page.id UUID — computeHistoryJob arms it under page.id), not the raw
+    // doc-name id which may be a slugId for a `page.<slugId>` doc (#260), or the
+    // remove silently misses. The burst marker is keyed by documentName (like its
+    // sibling per-document maps), and is also cleaned in afterUnloadDocument.
+    if (versionedPageId) {
+      await this.historyQueue.remove(versionedPageId).catch(() => undefined);
+    }
+    this.idleBurstStart.delete(documentName);
+
+    if (result) {
+      document.broadcastStateless(
+        JSON.stringify({
+          type: 'version.saved',
+          historyId: result.historyId,
+          kind: result.kind,
+          alreadySaved: result.alreadySaved,
+        }),
+      );
+    }
+  }
+
   async onChange(data: onChangePayload) {
     const documentName = data.documentName;
     const userId = data.context?.user?.id;
@@ -586,6 +783,10 @@ export class PersistenceExtension implements Extension {
     this.contributors.delete(documentName);
     this.agentTouched.delete(documentName);
     this.intentionalClear.delete(documentName);
+    // #370 — drop the idle-burst marker with the other per-document maps so it
+    // cannot accumulate across the process lifetime for never-manually-saved
+    // pages. The pending idle job (if any) is a self-expiring BullMQ delayed job.
+    this.idleBurstStart.delete(documentName);
   }
 
   private consumeContributors(documentName: string): string[] {
@@ -617,19 +818,80 @@ export class PersistenceExtension implements Extension {
 
   private async enqueuePageHistory(
     page: Page,
+    documentName: string,
     lastUpdatedSource: string,
   ): Promise<void> {
-    // Job id + delay arithmetic lives in the pure `computeHistoryJob` (see its
-    // doc comment for the agent-delay-0 / age-based-debounce invariants).
+    // #370 — trailing idle debounce with a max-wait ceiling. One pending idle
+    // job per page (jobId = page.id); on every store we remove the pending
+    // delayed job and re-add it, so the snapshot lands `delay` after edits go
+    // quiet rather than once per store (precedent: workspace.service.ts).
+    // remove() on a delayed job simply deletes it (0 if absent, no throw); if the
+    // job is already ACTIVE and the remove is a no-op, the add still de-dups and
+    // the processor's isDeepStrictEqual gate collapses the duplicate content.
+    //
+    // The FIRST arm of a burst records `burstStart`; computeHistoryJob shrinks
+    // the delay to the remaining max-wait budget from that point, so a continuous
+    // session cannot re-arm the trailing timer forever and starve the snapshot.
+    // A burst marker older than THIS TIER's max-wait means the previous idle job
+    // has already fired — start a fresh window instead of firing immediately on
+    // the next edit. Must use the SAME source-specific max-wait computeHistoryJob
+    // uses (agent 5m / user 10m): a hardcoded USER ceiling would leave an agent
+    // burst's marker stale for 5..10m, forcing delay=0 on every store in that
+    // window and writing one idle row per store — exactly the per-store bloat the
+    // debounce exists to prevent, on the continuous-agent path.
+    const maxWait =
+      lastUpdatedSource === 'agent' ? IDLE_MAX_WAIT_AGENT : IDLE_MAX_WAIT_USER;
+    const now = Date.now();
+    // Keyed by documentName (see the map declaration) so afterUnloadDocument can
+    // clean it; the queue jobId stays page.id (computeHistoryJob) as required.
+    let burstStart = this.idleBurstStart.get(documentName);
+    if (burstStart === undefined || now - burstStart >= maxWait) {
+      burstStart = now;
+      this.idleBurstStart.set(documentName, burstStart);
+    }
+
     const { jobId, delay } = computeHistoryJob(
       page,
       lastUpdatedSource,
-      Date.now(),
+      burstStart,
+      now,
     );
 
+    // remove-then-add trailing-debounce idiom, and its ONE race. We delete the
+    // pending delayed job and re-add it under the same jobId so the timer resets
+    // to the trailing edge of the burst. The race is the small window between
+    // these two awaits: if the delayed job's `delay` elapses in that gap it goes
+    // ACTIVE, and then:
+    //   - remove() on an active/locked job is a no-op (BullMQ won't yank a job a
+    //     worker holds), and our `.catch(() => undefined)` swallows that too; and
+    //   - add() with a jobId that already exists (the now-active job's id) is
+    //     DROPPED by BullMQ — a duplicate add is a no-op.
+    // So this store fails to re-arm the trailing job: the just-fired snapshot
+    // captured content up to the moment it went active, and THIS edit is left
+    // without a pending trailing job. It is bounded and self-healing — the NEXT
+    // store re-arms a fresh delayed job (the id is free again once the active job
+    // completes / removeOnComplete frees it), and the processor's
+    // isDeepStrictEqual gate collapses any content-identical duplicate. The only
+    // uncovered case is when the racing store was the LAST in the session: the
+    // tail edits made after the job went active get NO trailing snapshot until
+    // the next edit re-arms one. That is an acceptable safety-net gap (a manual
+    // Save, a source-transition boundary, or simply the next edit all still cover
+    // it), which is why the reviewer accepts documenting it here rather than
+    // adding a post-add "did the add actually arm a job?" re-check.
+    //
+    // NOTE — do NOT "unify" this with the neighbouring embed-debounce idiom
+    // (aiQueue.add of PAGE_CONTENT_UPDATED above): that one uses a STABLE jobId
+    // and NO remove(), relying purely on BullMQ coalescing a repeated add under
+    // the same id, because a re-embed only needs to eventually run once on the
+    // latest content and re-anchoring its delay on every keystroke is undesirable.
+    // THIS idiom deliberately removes-then-adds precisely to PUSH the delay back
+    // to the trailing edge on every store (a true debounce), which coalescing
+    // alone cannot do. Collapsing them would silently change the history cadence.
+    await this.historyQueue.remove(jobId).catch(() => undefined);
+
     await this.historyQueue.add(
       QueueJob.PAGE_HISTORY,
-      { pageId: page.id } as IPageHistoryJob,
+      { pageId: page.id, kind: 'idle' } as IPageHistoryJob,
       { jobId, delay },
     );
   }

apps/server/src/collaboration/processors/history.processor.spec.ts

@@ -66,6 +66,15 @@ describe('HistoryProcessor.process', () => {
     notificationQueue = { add: jest.fn().mockResolvedValue(undefined) };
     generalQueue = { add: jest.fn().mockResolvedValue(undefined) };
 
+    // #370 F3 — the processor now serializes its find+save under a page-row lock
+    // via executeTx. A db whose transaction().execute(fn) runs fn with a trx stub
+    // drives the real executeTx() helper without a database.
+    const db = {
+      transaction: () => ({
+        execute: (fn: (trx: any) => Promise<any>) => fn({ __trx: true }),
+      }),
+    };
+
     // WorkerHost's constructor reads `this.worker`; passing repos positionally
     // matches the constructor and avoids the Nest DI container.
     proc = new HistoryProcessor(
@@ -73,6 +82,7 @@ describe('HistoryProcessor.process', () => {
       pageRepo as any,
       collabHistory as any,
       watcherService as any,
+      db as any,
       notificationQueue as any,
       generalQueue as any,
     );
@@ -126,15 +136,26 @@ describe('HistoryProcessor.process', () => {
     await proc.process(buildJob());
 
     expect(collabHistory.popContributors).toHaveBeenCalledWith(PAGE_ID);
+    // #370 F3/F9 — the snapshot decision runs under a page-row lock. Pin the lock
+    // structurally so a refactor that drops withLock/trx (silently reintroducing
+    // the TOCTOU double-insert) turns this red. The tx stub is { __trx: true }.
+    expect(pageRepo.findById).toHaveBeenCalledWith(
+      PAGE_ID,
+      expect.objectContaining({ withLock: true, trx: { __trx: true } }),
+    );
+    // #370 F7 — addPageWatchers MUST receive the trx, or its FK-check runs on a
+    // separate connection and self-deadlocks against our FOR UPDATE. Asserting
+    // the trx arg here is exactly what would have caught that regression.
     expect(watcherService.addPageWatchers).toHaveBeenCalledWith(
       ['u1', 'u2'],
       PAGE_ID,
       SPACE_ID,
       WORKSPACE_ID,
+      { __trx: true },
     );
     expect(pageHistoryRepo.saveHistory).toHaveBeenCalledWith(
       expect.objectContaining({ id: PAGE_ID }),
-      { contributorIds: ['u1', 'u2'] },
+      { contributorIds: ['u1', 'u2'], kind: 'idle', trx: { __trx: true } },
     );
     expect(generalQueue.add).toHaveBeenCalledWith(
       QueueJob.PAGE_BACKLINKS,
@@ -186,6 +207,48 @@ describe('HistoryProcessor.process', () => {
     ]);
   });
 
+  it('COMMIT failure (throw outside the tx callback) → contributors RESTORED', async () => {
+    // #370 F8 — a commit-time failure throws OUTSIDE the callback, so the inner
+    // try/catch does not run; the outer catch must restore the popped set (else a
+    // BullMQ retry writes an unattributed version). Use a db whose execute() runs
+    // the callback THEN throws, simulating a commit abort.
+    pageHistoryRepo.findPageLastHistory.mockResolvedValue({
+      content: { type: 'doc', content: [] },
+    });
+    const commitFail = {
+      transaction: () => ({
+        execute: async (fn: (trx: any) => Promise<any>) => {
+          await fn({ __trx: true }); // callback succeeds (saveHistory ok)
+          throw new Error('commit aborted'); // ...but the COMMIT fails
+        },
+      }),
+    };
+    const procCommitFail = new HistoryProcessor(
+      pageHistoryRepo as any,
+      pageRepo as any,
+      collabHistory as any,
+      watcherService as any,
+      commitFail as any,
+      notificationQueue as any,
+      generalQueue as any,
+    );
+    jest
+      .spyOn(procCommitFail['logger'], 'error')
+      .mockImplementation(() => undefined);
+
+    await expect(procCommitFail.process(buildJob())).rejects.toThrow(
+      'commit aborted',
+    );
+    // The inner catch did NOT run (save succeeded), so only the outer catch can
+    // restore — assert it did.
+    expect(collabHistory.addContributors).toHaveBeenCalledWith(PAGE_ID, [
+      'u1',
+      'u2',
+    ]);
+    // And the post-snapshot queue work must NOT have run (we rethrew).
+    expect(generalQueue.add).not.toHaveBeenCalled();
+  });
+
   it('backlinks + notification queue failures are swallowed (history still committed)', async () => {
     pageHistoryRepo.findPageLastHistory.mockResolvedValue({
       content: { type: 'doc', content: [] },

apps/server/src/collaboration/processors/history.processor.ts

@@ -19,6 +19,9 @@ import { isDeepStrictEqual } from 'node:util';
 import { CollabHistoryService } from '../services/collab-history.service';
 import { WatcherService } from '../../core/watcher/watcher.service';
 import { isEmptyParagraphDoc } from '../collaboration.util';
+import { InjectKysely } from 'nestjs-kysely';
+import { KyselyDB } from '@docmost/db/types/kysely.types';
+import { executeTx } from '@docmost/db/utils';
 
 @Processor(QueueName.HISTORY_QUEUE)
 export class HistoryProcessor extends WorkerHost implements OnModuleDestroy {
@@ -29,6 +32,7 @@ export class HistoryProcessor extends WorkerHost implements OnModuleDestroy {
     private readonly pageRepo: PageRepo,
     private readonly collabHistory: CollabHistoryService,
     private readonly watcherService: WatcherService,
+    @InjectKysely() private readonly db: KyselyDB,
     @InjectQueue(QueueName.NOTIFICATION_QUEUE) private notificationQueue: Queue,
     @InjectQueue(QueueName.GENERAL_QUEUE) private generalQueue: Queue,
   ) {
@@ -41,6 +45,9 @@ export class HistoryProcessor extends WorkerHost implements OnModuleDestroy {
     try {
       const { pageId } = job.data;
 
+      // Read the page WITHOUT a lock first, only to bail early on the two cheap
+      // no-write cases (page gone / empty first snapshot) without opening a
+      // transaction. The authoritative check-then-write happens locked below.
       const page = await this.pageRepo.findById(pageId, {
         includeContent: true,
       });
@@ -51,40 +58,109 @@ export class HistoryProcessor extends WorkerHost implements OnModuleDestroy {
         return;
       }
 
-      const lastHistory = await this.pageHistoryRepo.findPageLastHistory(
-        pageId,
-        { includeContent: true },
-      );
+      // #370 F3 — the snapshot decision (findPageLastHistory → saveHistory) must
+      // be serialized against manual-save/boundary writers, which run under a
+      // page-row lock in onStoreDocument. Without it, this processor and a
+      // concurrent manual-save each read the same lastHistory (MVCC), both see
+      // content != lastHistory, and both insert — producing two page_history rows
+      // with IDENTICAL content (one 'idle', one 'manual'), defeating
+      // promote-not-dup and the version-vs-autosave split. Taking the same
+      // page-row lock makes the second writer observe the first's committed row so
+      // the isDeepStrictEqual gate collapses the duplicate. Only the read+write
+      // is transacted; the post-snapshot queue work stays outside.
+      let contributorIds: string[] = [];
+      let snapshotWritten = false;
+      let lastHistoryContent: unknown;
+      // #370 F8 — the contributor set popped from Redis (destructive SPOP) must be
+      // restored if the snapshot does not durably land. The inner try/catch only
+      // covers a throw INSIDE the callback; a COMMIT failure (connection drop,
+      // serialization/deadlock abort on commit — the transient class the epic
+      // already retries) throws OUTSIDE it, rolling the snapshot back while the
+      // pop is already gone. We track the popped set here and restore it in the
+      // outer catch so a BullMQ retry re-attributes the version. addContributors
+      // is an idempotent Redis SADD, so a double-restore is harmless.
+      let poppedForRestore: string[] = [];
 
-      if (!lastHistory && isEmptyParagraphDoc(page.content as any)) {
-        this.logger.debug(
-          `Skipping first history for page ${pageId}: empty content`,
-        );
-        await this.collabHistory.clearContributors(pageId);
+      try {
+        await executeTx(this.db, async (trx) => {
+          const lockedPage = await this.pageRepo.findById(pageId, {
+            includeContent: true,
+            withLock: true,
+            trx,
+          });
+          if (!lockedPage) return;
+
+          const lastHistory = await this.pageHistoryRepo.findPageLastHistory(
+            pageId,
+            { includeContent: true, trx },
+          );
+          lastHistoryContent = lastHistory?.content;
+
+          if (!lastHistory && isEmptyParagraphDoc(lockedPage.content as any)) {
+            this.logger.debug(
+              `Skipping first history for page ${pageId}: empty content`,
+            );
+            return;
+          }
+
+          if (
+            lastHistory &&
+            isDeepStrictEqual(lastHistory.content, lockedPage.content)
+          ) {
+            return; // already snapshotted at this content — nothing to write
+          }
+
+          contributorIds = await this.collabHistory.popContributors(pageId);
+          poppedForRestore = contributorIds;
+          try {
+            // Pass `trx` so the watcher insert's FK check (FOR KEY SHARE on
+            // pages[pageId]) runs on the SAME connection that already holds the
+            // FOR UPDATE lock from findById — otherwise it takes the FK lock on a
+            // separate pool connection and self-deadlocks against our own tx.
+            await this.watcherService.addPageWatchers(
+              contributorIds,
+              pageId,
+              lockedPage.spaceId,
+              lockedPage.workspaceId,
+              trx,
+            );
+
+            // #370 — every job on this queue is a trailing idle-flush autosnapshot.
+            await this.pageHistoryRepo.saveHistory(lockedPage, {
+              contributorIds,
+              kind: job.data.kind ?? 'idle',
+              trx,
+            });
+            snapshotWritten = true;
+            this.logger.debug(`History created for page: ${pageId}`);
+          } catch (err) {
+            await this.collabHistory.addContributors(pageId, contributorIds);
+            poppedForRestore = [];
+            throw err;
+          }
+        });
+      } catch (err) {
+        // A throw here means the tx did NOT commit (callback threw, or the commit
+        // itself failed and rolled back). If we popped contributors and the inner
+        // catch did not already restore them, restore now so the retry keeps
+        // attribution. snapshotWritten is irrelevant: it is set before commit, so
+        // it can be true even when the commit rolled the snapshot back.
+        if (poppedForRestore.length) {
+          await this.collabHistory.addContributors(pageId, poppedForRestore);
+        }
+        throw err;
+      }
+
+      // No snapshot written (page vanished / empty-first / unchanged content) →
+      // clear the contributor set for the skip cases and stop.
+      if (!snapshotWritten) {
+        if (!lastHistoryContent && isEmptyParagraphDoc(page.content as any)) {
+          await this.collabHistory.clearContributors(pageId);
+        }
         return;
       }
 
-      if (
-        !lastHistory ||
-        !isDeepStrictEqual(lastHistory.content, page.content)
-      ) {
-        const contributorIds = await this.collabHistory.popContributors(pageId);
-
-        try {
-          await this.watcherService.addPageWatchers(
-            contributorIds,
-            pageId,
-            page.spaceId,
-            page.workspaceId,
-          );
-
-          await this.pageHistoryRepo.saveHistory(page, { contributorIds });
-          this.logger.debug(`History created for page: ${pageId}`);
-        } catch (err) {
-          await this.collabHistory.addContributors(pageId, contributorIds);
-          throw err;
-        }
-
+      {
         const mentions = extractMentions(page.content);
         const pageMentions = extractPageMentions(mentions);
         const internalLinkSlugIds = extractInternalLinkSlugIds(page.content);
@@ -102,7 +178,7 @@ export class HistoryProcessor extends WorkerHost implements OnModuleDestroy {
             );
           });
 
-        if (contributorIds.length > 0 && lastHistory?.content) {
+        if (contributorIds.length > 0 && lastHistoryContent) {
           await this.notificationQueue
             .add(QueueJob.PAGE_UPDATED, {
               pageId,

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

@@ -1,122 +1,42 @@
 import { Injectable, Logger, OnModuleDestroy } from '@nestjs/common';
 
 /**
- * In-memory run-stream registry (#184 phase 1.5, step-aligned retention #491). A
- * durable agent run tees its SSE frames here (via
- * `pipeUIMessageStreamToResponse({ consumeSseStream })`) so a LATE tab — one that
- * reloaded, or opened after the starter dropped — can attach through
- * `GET /ai-chat/runs/:chatId/stream`, be handed the TAIL past the step it already
- * has persisted, and then follow the live tail as a normal streamer.
+ * In-memory run-stream registry (#184 phase 1.5). A durable agent run tees its
+ * SSE frames here (via `pipeUIMessageStreamToResponse({ consumeSseStream })`)
+ * so a LATE tab — one that reloaded, or opened after the starter dropped — can
+ * attach through `GET /ai-chat/runs/:chatId/stream`, replay the frames buffered
+ * so far, and then follow the live tail as a normal streamer.
  *
  * This is deliberately single-process and best-effort: it holds nothing the DB
  * does not (the run + assistant row are the source of truth), so a process
  * restart simply drops in-flight entries and the client falls back to its
  * restore + degraded-poll path. The async `attach` return type is the seam for a
  * future phase-2 cross-process backend (Redis) — the interface does not change.
- *
- * ── #491 step-aligned retention (the OOM fix) ────────────────────────────────
- * The old registry buffered up to 32MB of raw SSE frames PER active run (V8 ~2×
- * in memory) and, on attach, blasted the WHOLE buffer to the socket synchronously
- * with no drain — a handful of marathon runs on a 1GB container OOM'd. #491 caps
- * the ring at a few MB (env-tunable, default 4MB) and keeps it there by ROTATING:
- *
- *  - Every buffered frame is STAMPED with a step number at tee (see ingestFrame).
- *    Convention: the stamp of a frame is the number of `finish-step` parts seen
- *    BEFORE it (starting at 0). The finish-step frame itself carries the current
- *    value, THEN the counter increments. So a frame stamped `s` is the content of
- *    the (s+1)-th step — 0-based step index `s` — and the stamp aligns EXACTLY
- *    with `metadata.stepsPersisted`: a client whose persisted `stepsPersisted` is
- *    N has steps 0..N-1 on disk (and in its seed) and needs the tail `stamp >= N`.
- *
- *  - The ring rotates ONLY on a CONFIRMED persist of step N
- *    (`confirmPersistedStep`), dropping frames with `stamp < N` (those steps are
- *    now on disk and a fresh client seed carries them). A NON-confirmed step is
- *    never rotated away, so a persist FAILURE just makes the ring cover MORE
- *    (auto-safe). This is the anti-inversion rule: a naive "rotate in .then()"
- *    that rotated after an UNwritten step would drop a step nobody has → silent
- *    hole. Rotation is gated on a real, successful persist.
- *
- *  - If the ring still exceeds its byte cap after rotation (a single fat step, or
- *    a lagging persist), the OLDEST frames are evicted to stay bounded. Evicting a
- *    not-yet-persisted frame opens a GAP: an attach whose N falls at or below an
- *    evicted step answers 204 and the client degrades to restore+poll. The gap is
- *    NOT sticky — the coverage floor is recomputed from the ring, so a later
- *    persist that rotates past the holey steps clears it.
- *
- * ── attach numbering / coverage (the wire convention) ────────────────────────
- * The step marker N comes ONLY FROM THE CLIENT (a query param). The server never
- * reads the row to derive N — a server-side N from a stale seed would open a
- * silent one-step hole. N is the client's persisted `stepsPersisted` (a COUNT):
- *   - the tail it needs = frames with `stamp >= N`;
- *   - coverage is OK ⟺ `coverageFloor(entry) <= N`, where coverageFloor is the
- *     smallest step FULLY present in the ring (its smallest retained stamp, bumped
- *     by one when that leading step was only partially evicted by overflow). If
- *     `coverageFloor > N` the ring starts AFTER the client's frontier (a hole, or
- *     the client's seed simply lagged behind a rotation) → 204 → the client
- *     refetches (a larger N) and re-attaches.
- * The N cutoff is applied in ALL branches, INCLUDING the finished-retained replay.
- *
- * ── same-tick invariants (unchanged, still load-bearing) ─────────────────────
- * invariant 1: only the matching run may mutate/observe an entry (runId check).
- * invariant 2: retention deletes ONLY its own entry (a replacement may own the key).
- * invariant 3: open() over a live entry mirrors the done-path (subscribers released).
- * invariant 4: the tail SLICE + subscriber registration happen in ONE synchronous
- *              tick inside attach() — no await between them — so a concurrently
- *              ingested frame is EITHER in the snapshot (buffered before the sync
- *              block, and the just-added subscriber never sees it) OR fanned out to
- *              the paused subscriber's `pending` (ingested after) — never both and
- *              never neither: no loss, no duplication. NOTE (#491): the controller
- *              now AWAITS the drain-respecting tail write BEFORE calling start(), so
- *              frames ingested during that await accumulate in `pending`; this is
- *              bounded by the subscriber cap (an overflow degrades start() to an
- *              end(), a 204-equivalent). It is the SYNCHRONOUS snapshot+registration
- *              — not a same-tick start() — that makes this correct.
- * invariant 5: the controller wires close-cleanup BEFORE any write.
- * invariant 6: no cross-run replay — the `anchor` (the client's assistant row id)
- *              must match this run's assistant id, or a foreign run's transcript
- *              would be appended to the client's message.
  */
 
 /** How long a finished entry is retained for late attach (replay + immediate end). */
 export const RUN_STREAM_RETAIN_FINISHED_MS = 30_000;
 
 /**
- * DEFAULT per-run replay ring cap (#491, down from 32MB). SSE frames carry
- * UNcompacted tool outputs + framing overhead (×1.5–2 vs the persisted parts), so
- * a "2–3 large reads + reasoning" step routinely blows past 2MB; 4MB comfortably
- * holds a step or two of TAIL, which is all a resuming client needs (steps below
- * its persisted frontier come from the seed, not the ring). The ring stays bounded
- * because it rotates on every confirmed persist; this cap is only the ceiling for
- * the un-persisted tail between rotations. Env-tunable via
- * AI_CHAT_RUN_STREAM_MAX_BUFFER_BYTES (bytes); a 0/invalid value falls back to this.
+ * Per-run replay buffer cap. Past this the buffer is dropped (attach -> 204, and
+ * the client falls back to its restore + degraded-poll path, #430).
+ *
+ * Raised from 4MB to 32MB (#430): marathon autonomous runs (11-25 min observed)
+ * stream far more than 4MB of SSE frames, so a live disconnect mid-run would find
+ * an already-overflowed buffer and could only degrade-poll instead of re-attaching
+ * to the live tail. 32MB comfortably covers those runs while staying bounded.
+ *
+ * Memory cost: this is the WORST-CASE retained size PER ACTIVE run (the buffer is
+ * freed on finish + retention, or dropped immediately on overflow). With the small
+ * number of concurrent autonomous runs a single workspace realistically has, 32MB
+ * each is an acceptable ceiling; the overflow->204->degraded-poll fallback remains
+ * the backstop for anything larger, so correctness never depends on this bound.
  */
-export const AI_CHAT_RUN_STREAM_MAX_BUFFER_BYTES = 4 * 1024 * 1024;
+export const RUN_STREAM_MAX_BUFFER_BYTES = 32 * 1024 * 1024;
 
-// 2× the ring cap: a just-written full-tail burst alone can never trip the
-// per-subscriber cap (see controller); only a genuinely stalled socket can. This
-// derivative relationship is preserved even when the ring cap is env-overridden.
-export const SUBSCRIBER_MAX_BUFFERED_BYTES = 2 * AI_CHAT_RUN_STREAM_MAX_BUFFER_BYTES;
-
-/**
- * A finish-step boundary frame is exactly `data: {"type":"finish-step"...}\n\n`
- * (verified empirically against ai@6.0.207 — each UI-message-stream part is a
- * single `data: {json}\n\n` event, never split across `data:` lines, and `type`
- * is always the first key). A prefix match is cheaper than JSON.parse-per-frame
- * and has no false positives: a literal `"type":"finish-step"` inside a text
- * delta is JSON-escaped (`\"type\":...`), and the frame would start with
- * `data: {"type":"text-delta"` anyway.
- */
-const FINISH_STEP_FRAME_PREFIX = 'data: {"type":"finish-step"';
-
-/** Resolve the ring cap from the environment, falling back to the default. */
-function resolveMaxBufferBytes(): number {
-  const raw = process.env.AI_CHAT_RUN_STREAM_MAX_BUFFER_BYTES;
-  if (!raw) return AI_CHAT_RUN_STREAM_MAX_BUFFER_BYTES;
-  const parsed = Number(raw);
-  return Number.isFinite(parsed) && parsed > 0
-    ? Math.floor(parsed)
-    : AI_CHAT_RUN_STREAM_MAX_BUFFER_BYTES;
-}
+// 2x the replay cap: a just-written full-replay burst alone can never trip the
+// per-subscriber cap (see controller); only a genuinely stalled socket can.
+export const SUBSCRIBER_MAX_BUFFERED_BYTES = 2 * RUN_STREAM_MAX_BUFFER_BYTES;
 
 export interface RunStreamCallbacks {
   onFrame: (frame: string) => void;
@@ -124,9 +44,6 @@ export interface RunStreamCallbacks {
 }
 
 export interface RunStreamAttachment {
-  // The synthetic `start` frame (carrying { runId, chatId }) followed by the
-  // buffered TAIL filtered to `stamp >= N`. The controller writes these to the
-  // socket in chunks respecting drain, then calls start().
   replay: string[];
   finished: boolean;
   start(): void; // drain pending frames (order preserved) and go live
@@ -136,19 +53,14 @@ export interface RunStreamAttachment {
 interface Subscriber extends RunStreamCallbacks {
   started: boolean;
   pending: string[];
-  // Byte size of `pending`, capped at the subscriber cap. `start()` is called in
-  // the SAME tick as `attach()` today, so `pending` never holds more than one
-  // microtask of frames — but the controller writes the (potentially large) tail
-  // respecting drain BEFORE start(), so a stalled socket can accumulate here; the
-  // cap is the structural backstop (an overflow degrades start() to an end()).
+  // Byte size of `pending`, capped at SUBSCRIBER_MAX_BUFFERED_BYTES. `start()` is
+  // called in the SAME tick as `attach()` today (see attach), so `pending` never
+  // holds more than one microtask of frames — but the async `attach` signature is
+  // a phase-2 seam: an await between attach and start would let a stalled paused
+  // subscriber buffer the WHOLE run here. The cap is the structural backstop.
   pendingBytes: number;
   overflowed: boolean;
   pendingEnd: boolean;
-  // The client's step frontier N: this subscriber only receives frames with
-  // `stamp >= minStamp` (the tail past what it already persisted). Live frames
-  // always satisfy this (their stamp is the current, highest step), so it only
-  // filters the rare out-of-order below-frontier frame.
-  minStamp: number;
 }
 
 interface Entry {
@@ -156,20 +68,8 @@ interface Entry {
   // The persisted assistant row id of this run (set at bind; undefined if the
   // seed failed). Used by the attach anchor check (invariant 6).
   assistantMessageId?: string;
-  // Parallel arrays: frames[i] is the SSE string, stamps[i] its step number.
   frames: string[];
-  stamps: number[];
   bytes: number;
-  // The running step counter used to stamp the NEXT frame (number of finish-step
-  // frames seen so far).
-  currentStamp: number;
-  // The highest confirmed `stepsPersisted`: frames with stamp < persistedFloor are
-  // on disk (safe to drop, never re-buffered). Monotonic (confirmPersistedStep).
-  persistedFloor: number;
-  // The highest stamp EVICTED by an overflow (unsafe) drop, -1 if none. Used to
-  // detect a partially-evicted leading step when computing the coverage floor.
-  overflowThroughStamp: number;
-  // Sticky-for-logging only: at least one unsafe (overflow) eviction happened.
   overflowed: boolean;
   finished: boolean;
   subscribers: Set<Subscriber>;
@@ -180,10 +80,6 @@ interface Entry {
 export class AiChatStreamRegistryService implements OnModuleDestroy {
   private readonly logger = new Logger(AiChatStreamRegistryService.name);
   private readonly entries = new Map<string, Entry>(); // key: chatId
-  // Env-resolved caps (per instance) so a deployment can tune the ceiling without
-  // a code change. The subscriber cap keeps the documented 2× relationship.
-  readonly maxBufferBytes = resolveMaxBufferBytes();
-  readonly subscriberMaxBufferedBytes = 2 * this.maxBufferBytes;
 
   /**
    * Register a fresh entry at the START of a run (before any frame), so a tab
@@ -209,11 +105,7 @@ export class AiChatStreamRegistryService implements OnModuleDestroy {
     this.entries.set(chatId, {
       runId,
       frames: [],
-      stamps: [],
       bytes: 0,
-      currentStamp: 0,
-      persistedFloor: 0,
-      overflowThroughStamp: -1,
       overflowed: false,
       finished: false,
       subscribers: new Set<Subscriber>(),
@@ -258,34 +150,6 @@ export class AiChatStreamRegistryService implements OnModuleDestroy {
     void pump();
   }
 
-  /**
-   * Confirm that step `stepsPersisted` (a COUNT: steps 0..stepsPersisted-1) is on
-   * disk for this run, and ROTATE the ring: drop the buffered frames of those
-   * now-persisted steps (stamp < stepsPersisted). This is the ONLY thing that
-   * rotates the ring, and it is called ONLY after a genuinely SUCCESSFUL per-step
-   * persist (see ai-chat.service updateStreaming). A failed persist never calls
-   * it, so the ring covers more (auto-safe). Identity-checked (invariant 1) and
-   * monotonic (a stale lower count is ignored).
-   */
-  confirmPersistedStep(
-    chatId: string,
-    runId: string,
-    stepsPersisted: number,
-  ): void {
-    const entry = this.entries.get(chatId);
-    if (!entry || entry.runId !== runId) return;
-    if (!Number.isFinite(stepsPersisted) || stepsPersisted <= entry.persistedFloor)
-      return;
-    entry.persistedFloor = stepsPersisted;
-    // Clean rotation: drop the persisted steps from the head. These frames are on
-    // disk + carried by a fresh client seed, so this NEVER opens a gap.
-    while (entry.frames.length > 0 && entry.stamps[0] < stepsPersisted) {
-      entry.bytes -= Buffer.byteLength(entry.frames[0]);
-      entry.frames.shift();
-      entry.stamps.shift();
-    }
-  }
-
   /**
    * Terminate a run's entry from the OUTER catch of the stream method (a failure
    * before/while wiring the pipe, so `done` will never arrive). Identity-checked
@@ -298,77 +162,36 @@ export class AiChatStreamRegistryService implements OnModuleDestroy {
   }
 
   /**
-   * Attach to a run's stream from the client's step frontier `n` (its persisted
-   * `stepsPersisted`). Async only for the phase-2 Redis seam — the body runs
-   * synchronously so the tail SLICE and the subscriber registration happen in ONE
-   * tick with no await between them (invariant 4).
+   * Attach to a run's stream. Async only for the phase-2 Redis seam — the body
+   * runs synchronously so the replay snapshot and the subscriber registration
+   * happen in ONE tick with no await between them (invariant 4): a frame ingested
+   * concurrently cannot slip into the gap and be lost or duplicated.
    *
    * Returns null (-> the caller answers 204) when:
-   *  - there is no entry;
-   *  - the `anchor` does not match this run's assistant id (invariant 6);
-   *  - the ring does not cover the client's frontier (coverageFloor > n): a hole
-   *    from overflow, or the client's seed simply lagged behind a rotation. The
-   *    client then refetches (a larger n) and re-attaches.
-   *
-   * Otherwise the attachment's `replay` is a synthetic `start` frame (the run-fact
-   * on re-attach) followed by the buffered tail filtered to `stamp >= n`. For a
-   * FINISHED run this is replay-only (no subscriber) and ends after the replay —
-   * with n = N_final that tail is just the run's `finish` frame, so the client
-   * closes the stream. For a LIVE run a paused subscriber is registered; the
-   * caller writes the replay (respecting drain) then calls start() to drain the
-   * pending frames and go live.
+   *  - there is no entry, or it overflowed (replay is gone);
+   *  - expect=live with an anchor that does not match this run's assistant id
+   *    (invariant 6: a stripped tab must never replay a FOREIGN run's transcript);
+   *  - the run finished and the caller did not expect a live tail.
+   * A finished run with expect=live yields a replay-only attachment (no
+   * subscriber registered). Otherwise a paused subscriber is registered and the
+   * caller replays `replay`, then calls start() to drain and go live.
    */
   async attach(
     chatId: string,
+    expectLive: boolean,
     anchor: string | undefined,
-    // The client's persisted step frontier. `null` = a NOT-tail-aware client (no
-    // `n` query param) — a legacy/parameterless tab that expects the old
-    // "finished -> 204 -> poll" contract; distinct from `0` (a tail-aware client
-    // with nothing persisted yet).
-    n: number | null,
     cb: RunStreamCallbacks,
   ): Promise<RunStreamAttachment | null> {
     const entry = this.entries.get(chatId);
-    if (!entry) return null;
+    if (!entry || entry.overflowed) return null;
     // Invariant 6: cross-run replay is forbidden. Before bind, assistantMessageId
     // is undefined and mismatches any anchor -> 204 -> client restore+poll path.
-    if (anchor && entry.assistantMessageId !== anchor) return null;
-    // #491 regression guard (#137/#161 dup): a NOT-tail-aware client (no `n`)
-    // resuming a FINISHED run must 204 and poll — the old `finished && !expectLive`
-    // gate. Without this, a missing `n` collapsing to frontier 0 would serve the
-    // WHOLE tail of a finished, NON-rotated run (coverageFloor 0), and a
-    // parameterless client that never stripped its transcript would APPEND that
-    // full replay onto the steps it already shows -> duplicated text. A tail-aware
-    // client (n present, incl. n=0) still gets the tail past its frontier.
-    if (entry.finished && n === null) return null;
-    // A finished entry with NOTHING in the ring (aborted before the first frame,
-    // or fully overflowed) has no tail to deliver -> 204 -> the client polls.
-    if (entry.finished && entry.frames.length === 0) return null;
-    // A LIVE run with no `n` (legacy parameterless) replays from step 0 (the old
-    // behavior); a tail-aware client resumes from its frontier.
-    const frontier = n ?? 0;
-    const floor = this.coverageFloor(entry);
-    if (floor > frontier) {
-      this.logger.warn(
-        `run-stream attach gap for run=${entry.runId}: coverageFloor=${floor} ` +
-          `> client frontier=${frontier} -> 204 (client refetches + re-attaches)`,
-      );
-      return null;
-    }
-
-    const startFrame = this.buildStartFrame(chatId, entry.runId);
-    const sliceTail = (): string[] => {
-      const out: string[] = [startFrame];
-      for (let i = 0; i < entry.frames.length; i++) {
-        if (entry.stamps[i] >= frontier) out.push(entry.frames[i]);
-      }
-      return out;
-    };
-
-    if (entry.finished) {
+    if (expectLive && anchor && entry.assistantMessageId !== anchor) return null;
+    if (entry.finished && !expectLive) return null;
+    if (entry.finished && expectLive) {
       // Replay-only: the run is done, no subscriber is registered.
       return {
-        replay: sliceTail(),
+        replay: entry.frames.slice(),
         finished: true,
         start: () => undefined,
         unsubscribe: () => undefined,
@@ -383,12 +206,15 @@ export class AiChatStreamRegistryService implements OnModuleDestroy {
       pendingBytes: 0,
       overflowed: false,
       pendingEnd: false,
-      minStamp: frontier,
     };
-    // Register + snapshot in the SAME synchronous block (invariant 4). No await
-    // separates them, so a concurrently ingested frame cannot be lost/duplicated.
     entry.subscribers.add(sub);
-    const replay = sliceTail();
+    // Snapshot in the SAME synchronous block as the registration (invariant 4).
+    const replay = entry.frames.slice();
+    // CONTRACT: the caller MUST call start() in the SAME tick as this attach()
+    // returns — no await between them. While a subscriber is paused, every frame
+    // is buffered in sub.pending; a delayed start() lets a whole run accumulate
+    // there. The pendingBytes cap (see ingestFrame) is the structural backstop if
+    // that contract is ever broken (e.g. the phase-2 Redis await seam).
     return {
       replay,
       finished: false,
@@ -437,83 +263,24 @@ export class AiChatStreamRegistryService implements OnModuleDestroy {
     this.entries.clear();
   }
 
-  /** The synthetic `start` frame the tail is prefixed with — the source of the
-   *  run-fact (runId/chatId) on re-attach. A `start` frame does NOT reset the
-   *  client's message parts (ai@6.0.207 createStreamingUIMessageState), so it is
-   *  safe to prepend even when the sliced tail begins mid-message. */
-  private buildStartFrame(chatId: string, runId: string): string {
-    return `data: ${JSON.stringify({
-      type: 'start',
-      messageMetadata: { runId, chatId },
-    })}\n\n`;
-  }
-
-  /**
-   * The smallest step FULLY present in the ring: its smallest retained stamp, or
-   * (when the leading step was only partially evicted by an overflow) one past it.
-   * When the ring is empty it is the current step (only the live tail is coming).
-   * An attach at frontier `n` is covered ⟺ coverageFloor <= n.
-   */
-  private coverageFloor(entry: Entry): number {
-    // Empty ring: only the live tail is coming. The floor is the current step,
-    // but never below persistedFloor — a confirmed persist can rotate the ring
-    // empty while currentStamp still lags a beat behind on another connection, so
-    // max() keeps the invariant STRUCTURAL (a client with n = persistedFloor is
-    // always covered) rather than timing-dependent.
-    if (entry.frames.length === 0)
-      return Math.max(entry.currentStamp, entry.persistedFloor);
-    const min = entry.stamps[0];
-    return entry.overflowThroughStamp >= min ? min + 1 : min;
-  }
-
-  /**
-   * Buffer (step-stamped) + fan-out a single frame. The stamp is the number of
-   * finish-step frames seen BEFORE this one; a finish-step frame carries the
-   * current value and THEN increments the counter (so its stamp equals the 0-based
-   * index of the step it closes). Only frames at/above persistedFloor are buffered
-   * (already-persisted steps are on disk); the ring is then trimmed to the byte
-   * cap, an unsafe eviction opening a gap. Fan-out is always live (filtered per
-   * subscriber by its frontier).
-   */
+  /** Buffer + fan-out a single frame. See invariant/overflow semantics inline. */
   private ingestFrame(entry: Entry, frame: string): void {
-    const size = Buffer.byteLength(frame);
-    const stamp = entry.currentStamp;
-    if (frame.startsWith(FINISH_STEP_FRAME_PREFIX)) {
-      entry.currentStamp = stamp + 1;
-    }
-
-    // Buffer for replay only if this step is not already persisted+rotated away.
-    if (stamp >= entry.persistedFloor) {
+    entry.bytes += Buffer.byteLength(frame);
+    if (!entry.overflowed) {
       entry.frames.push(frame);
-      entry.stamps.push(stamp);
-      entry.bytes += size;
-      // Enforce the ring cap. Evicting a not-yet-persisted frame (stamp >=
-      // persistedFloor) opens a GAP; a leftover persisted frame (< floor) is a
-      // safe drop. Keep evicting until the ring is back under the cap.
-      while (entry.bytes > this.maxBufferBytes && entry.frames.length > 0) {
-        const evStamp = entry.stamps[0];
-        entry.bytes -= Buffer.byteLength(entry.frames[0]);
-        entry.frames.shift();
-        entry.stamps.shift();
-        if (evStamp >= entry.persistedFloor) {
-          if (evStamp > entry.overflowThroughStamp)
-            entry.overflowThroughStamp = evStamp;
-          if (!entry.overflowed) {
-            entry.overflowed = true;
-            this.logger.warn(
-              `run-stream ring overflow for run=${entry.runId}: an un-persisted ` +
-                `step was evicted to stay under ${this.maxBufferBytes}B; a late ` +
-                `attach at an evicted step will 204 until a later persist confirms`,
-            );
-          }
-        }
+      if (entry.bytes > RUN_STREAM_MAX_BUFFER_BYTES) {
+        // The crossing frame was already counted AND (below) fanned out; only the
+        // replay buffer is dropped. After overflow no more frames are buffered,
+        // but live fan-out continues.
+        entry.overflowed = true;
+        entry.frames = [];
+        this.logger.warn(
+          `run-stream buffer overflow for run=${entry.runId}; ` +
+            `late attach will 204 until the run ends`,
+        );
       }
     }
-
-    // Fan out live, filtered to each subscriber's frontier (a subscriber only
-    // wants the tail past the step it already persisted).
     for (const sub of entry.subscribers) {
-      if (stamp < sub.minStamp) continue;
       if (sub.started) {
         try {
           sub.onFrame(frame);
@@ -522,12 +289,12 @@ export class AiChatStreamRegistryService implements OnModuleDestroy {
         }
       } else {
         sub.pending.push(frame);
-        sub.pendingBytes += size;
-        if (sub.pendingBytes > this.subscriberMaxBufferedBytes) {
+        sub.pendingBytes += Buffer.byteLength(frame);
+        if (sub.pendingBytes > SUBSCRIBER_MAX_BUFFERED_BYTES) {
           // The paused subscriber's buffer overflowed — only possible if start()
-          // was delayed (the controller's drain-respecting tail write, or the
-          // phase-2 await seam). Drop it rather than buffer the whole run; on
-          // start() it degrades to an immediate end (a 204-equivalent).
+          // was delayed past the same-tick contract (the phase-2 await seam).
+          // Drop it rather than buffer the whole run; on start() it degrades to an
+          // immediate end (a 204-equivalent) instead of replaying a partial.
           sub.overflowed = true;
           sub.pending = [];
           entry.subscribers.delete(sub);

apps/server/src/core/ai-chat/ai-chat-stream-registry.spec.ts

@@ -1,27 +1,19 @@
 import {
   AiChatStreamRegistryService,
-  AI_CHAT_RUN_STREAM_MAX_BUFFER_BYTES,
+  RUN_STREAM_MAX_BUFFER_BYTES,
   RUN_STREAM_RETAIN_FINISHED_MS,
+  SUBSCRIBER_MAX_BUFFERED_BYTES,
   RunStreamCallbacks,
 } from './ai-chat-stream-registry.service';
 
 /**
- * Unit tests for the in-memory run-stream registry (#184 phase 1.5, step-aligned
- * retention #491). The registry is the whole of the resumable-transport contract:
- * step-stamped retention, tail-only attach at the client's frontier N, the
- * confirmed-persist ring rotation (and the anti-inversion rule), the memory bound,
- * the overflow gap, paused -> live hand-off, retention, the anchor check
- * (invariant 6), and the mirror-the-done-path replace semantics (invariant 3).
+ * Unit tests for the in-memory run-stream registry (#184 phase 1.5). The registry
+ * is the whole of the resumable-transport contract: replay ordering, paused ->
+ * live hand-off, overflow, retention, the anchor check (invariant 6), and the
+ * mirror-the-done-path replace semantics (invariant 3). Every enumerated case in
+ * the issue's task 1.5 has a test here.
  */
 
-// Real ai@6 UI-message-stream SSE frames are `data: {json}\n\n`, one part each.
-const sse = (part: Record<string, unknown>): string =>
-  `data: ${JSON.stringify(part)}\n\n`;
-const finishStep = (): string => sse({ type: 'finish-step' });
-const textDelta = (id: string, delta: string): string =>
-  sse({ type: 'text-delta', id, delta });
-const finish = (): string => sse({ type: 'finish' });
-
 // A ReadableStream whose frames the test pushes explicitly, plus close/error.
 function makePushStream(): {
   stream: ReadableStream<string>;
@@ -66,9 +58,6 @@ function collector(): {
   };
 }
 
-// The tail past the synthetic start frame (replay[0] is always the start frame).
-const tail = (replay: string[]): string[] => replay.slice(1);
-
 describe('AiChatStreamRegistryService', () => {
   const CHAT = 'chat-1';
   let registry: AiChatStreamRegistryService;
@@ -82,21 +71,7 @@ describe('AiChatStreamRegistryService', () => {
     registry.onModuleDestroy();
   });
 
-  it('prepends a synthetic start frame carrying { runId, chatId }', async () => {
-    registry.open(CHAT, 'run-1');
-    const src = makePushStream();
-    registry.bind(CHAT, 'run-1', 'assist-1', src.stream);
-    src.push('a');
-    await flush();
-
-    const c = collector();
-    const att = (await registry.attach(CHAT, 'assist-1', 0, c.cb))!;
-    const start = JSON.parse(att.replay[0].replace(/^data: /, '').trim());
-    expect(start.type).toBe('start');
-    expect(start.messageMetadata).toEqual({ runId: 'run-1', chatId: CHAT });
-  });
-
-  it('replays the buffered tail (from frontier 0) in arrival order (live attach)', async () => {
+  it('replays frames in arrival order (live attach)', async () => {
     registry.open(CHAT, 'run-1');
     const src = makePushStream();
     registry.bind(CHAT, 'run-1', 'assist-1', src.stream);
@@ -106,13 +81,13 @@ describe('AiChatStreamRegistryService', () => {
     await flush();
 
     const c = collector();
-    const att = await registry.attach(CHAT, 'assist-1', 0, c.cb);
+    const att = await registry.attach(CHAT, false, undefined, c.cb);
     expect(att).not.toBeNull();
-    expect(tail(att!.replay)).toEqual(['a', 'b', 'c']);
+    expect(att!.replay).toEqual(['a', 'b', 'c']);
     expect(att!.finished).toBe(false);
   });
 
-  it('late attach gets the buffered prefix as tail plus the live tail', async () => {
+  it('late attach gets the full prefix as replay plus the live tail', async () => {
     registry.open(CHAT, 'run-1');
     const src = makePushStream();
     registry.bind(CHAT, 'run-1', 'assist-1', src.stream);
@@ -121,16 +96,17 @@ describe('AiChatStreamRegistryService', () => {
     await flush();
 
     const c = collector();
-    const att = (await registry.attach(CHAT, 'assist-1', 0, c.cb))!;
-    expect(tail(att.replay)).toEqual(['a', 'b']);
+    const att = (await registry.attach(CHAT, false, undefined, c.cb))!;
+    expect(att.replay).toEqual(['a', 'b']);
     att.start();
+    // Live tail arrives after start().
     src.push('c');
     src.push('d');
     await flush();
     expect(c.frames).toEqual(['c', 'd']);
   });
 
-  it('a paused subscriber receives frames buffered during pause in order, then live', async () => {
+  it('a paused subscriber receives frames buffered during pause in order, then live (no loss/reorder)', async () => {
     registry.open(CHAT, 'run-1');
     const src = makePushStream();
     registry.bind(CHAT, 'run-1', 'assist-1', src.stream);
@@ -138,45 +114,81 @@ describe('AiChatStreamRegistryService', () => {
     await flush();
 
     const c = collector();
-    const att = (await registry.attach(CHAT, 'assist-1', 0, c.cb))!;
-    expect(tail(att.replay)).toEqual(['a']);
+    // Attach (paused). Frames that arrive BEFORE start() must queue, not drop.
+    const att = (await registry.attach(CHAT, false, undefined, c.cb))!;
+    expect(att.replay).toEqual(['a']);
     src.push('b'); // arrives while paused -> pending
     src.push('c');
     await flush();
     expect(c.frames).toEqual([]); // nothing delivered yet (paused)
-    att.start();
+    att.start(); // drains pending in order
     expect(c.frames).toEqual(['b', 'c']);
-    src.push('d');
+    src.push('d'); // now live
     await flush();
     expect(c.frames).toEqual(['b', 'c', 'd']);
   });
 
   it('a run that finishes while a subscriber is paused ends it on start()', async () => {
     registry.open(CHAT, 'run-1');
-    registry.bind(CHAT, 'run-1', 'assist-1', makePushStream().stream);
     const c = collector();
-    const att = (await registry.attach(CHAT, 'assist-1', 0, c.cb))!;
+    const att = (await registry.attach(CHAT, false, undefined, c.cb))!;
+    // Terminate the run while the subscriber is still paused.
     registry.abortEntry(CHAT, 'run-1');
     expect(c.ended()).toBe(0); // paused: not ended yet
     att.start();
     expect(c.ended()).toBe(1); // start() drains + ends
   });
 
-  it('anchor mismatch returns null (and null before bind sets assistantMessageId)', async () => {
+  it('finished + expect=live returns a replay WITHOUT registering a subscriber', async () => {
+    registry.open(CHAT, 'run-1');
+    const src = makePushStream();
+    registry.bind(CHAT, 'run-1', 'assist-1', src.stream);
+    src.push('a');
+    src.push('b');
+    src.close();
+    await flush();
+
+    const c = collector();
+    const att = (await registry.attach(CHAT, true, undefined, c.cb))!;
+    expect(att.finished).toBe(true);
+    expect(att.replay).toEqual(['a', 'b']);
+    // No subscriber registered: start()/unsubscribe are no-ops and the entry has
+    // zero subscribers.
+    const entry = (registry as any).entries.get(CHAT);
+    expect(entry.subscribers.size).toBe(0);
+    att.start();
+    expect(c.frames).toEqual([]);
+  });
+
+  it('finished WITHOUT expect=live returns null', async () => {
+    registry.open(CHAT, 'run-1');
+    const src = makePushStream();
+    registry.bind(CHAT, 'run-1', 'assist-1', src.stream);
+    src.push('a');
+    src.close();
+    await flush();
+
+    const c = collector();
+    expect(await registry.attach(CHAT, false, undefined, c.cb)).toBeNull();
+  });
+
+  it('anchor mismatch with expect=live returns null (and null before bind sets assistantMessageId)', async () => {
     registry.open(CHAT, 'run-1');
     const c = collector();
     // Before bind: assistantMessageId is undefined -> mismatches any anchor.
-    expect(await registry.attach(CHAT, 'assist-1', 0, c.cb)).toBeNull();
+    expect(
+      await registry.attach(CHAT, true, 'assist-1', c.cb),
+    ).toBeNull();
 
     const src = makePushStream();
     registry.bind(CHAT, 'run-1', 'assist-1', src.stream);
     src.push('a');
     await flush();
     // Wrong anchor -> null (cross-run replay forbidden, invariant 6).
-    expect(await registry.attach(CHAT, 'other-id', 0, c.cb)).toBeNull();
+    expect(await registry.attach(CHAT, true, 'other-id', c.cb)).toBeNull();
   });
 
-  it('matching anchor attaches', async () => {
+  it('matching anchor with expect=live attaches', async () => {
     registry.open(CHAT, 'run-1');
     const src = makePushStream();
     registry.bind(CHAT, 'run-1', 'assist-1', src.stream);
@@ -184,39 +196,73 @@ describe('AiChatStreamRegistryService', () => {
     await flush();
 
     const c = collector();
-    const att = await registry.attach(CHAT, 'assist-1', 0, c.cb);
+    const att = await registry.attach(CHAT, true, 'assist-1', c.cb);
     expect(att).not.toBeNull();
-    expect(tail(att!.replay)).toEqual(['a']);
+    expect(att!.replay).toEqual(['a']);
   });
 
-  it('a throwing onFrame ejects only that subscriber; the ingest loop stays alive', async () => {
+  it('overflow: attach returns null, but the LIVE subscriber keeps receiving (incl. the crossing frame)', async () => {
     registry.open(CHAT, 'run-1');
     const src = makePushStream();
     registry.bind(CHAT, 'run-1', 'assist-1', src.stream);
 
-    const bad = collector();
-    const badAtt = (await registry.attach(CHAT, 'assist-1', 0, {
-      onFrame: () => {
-        throw new Error('boom');
-      },
-      onEnd: bad.cb.onEnd,
-    }))!;
-    badAtt.start();
+    // A live (started) subscriber attached before the flood.
+    const c = collector();
+    const att = (await registry.attach(CHAT, false, undefined, c.cb))!;
+    att.start();
 
-    const good = collector();
-    const goodAtt = (await registry.attach(CHAT, 'assist-1', 0, good.cb))!;
-    goodAtt.start();
-
-    src.push('a'); // bad throws on this frame -> ejected
-    src.push('b'); // good still receives both
+    // Cap-relative so it survives a buffer-cap change (#430): a quarter-cap frame
+    // means 5 frames comfortably exceed the replay cap; the last one crosses.
+    const chunk = 'x'.repeat(Math.floor(RUN_STREAM_MAX_BUFFER_BYTES / 4));
+    for (let i = 0; i < 5; i++) src.push(chunk + i);
     await flush();
 
     const entry = (registry as any).entries.get(CHAT);
-    expect(entry.subscribers.size).toBe(1);
-    expect(good.frames).toEqual(['a', 'b']);
+    expect(entry.overflowed).toBe(true);
+    expect(entry.bytes).toBeGreaterThan(RUN_STREAM_MAX_BUFFER_BYTES);
+    // The live subscriber received ALL 5 frames, including the crossing one.
+    expect(c.frames).toHaveLength(5);
+    expect(c.frames[4]).toBe(chunk + 4);
+
+    // A NEW attach after overflow gets null (replay buffer is gone).
+    const c2 = collector();
+    expect(await registry.attach(CHAT, false, undefined, c2.cb)).toBeNull();
   });
 
-  it('open() over a LIVE entry ends started subscribers once; a late done never touches the new entry (invariant 3)', async () => {
+  it('a paused subscriber whose pending buffer overflows is dropped and ends on start(); other subscribers keep receiving', async () => {
+    registry.open(CHAT, 'run-1');
+    const src = makePushStream();
+    registry.bind(CHAT, 'run-1', 'assist-1', src.stream);
+
+    // A: paused (start() deliberately delayed to simulate the phase-2 await seam).
+    const a = collector();
+    const attA = (await registry.attach(CHAT, false, undefined, a.cb))!;
+    // B: live (started) — its delivery must be unaffected by A's overflow.
+    const b = collector();
+    const attB = (await registry.attach(CHAT, false, undefined, b.cb))!;
+    attB.start();
+
+    // Cap-relative so it survives a buffer-cap change (#430): a quarter-of-the-
+    // per-subscriber-cap frame means 5 frames exceed A's paused-pending cap while
+    // B streams every frame live.
+    const chunk = 'x'.repeat(Math.floor(SUBSCRIBER_MAX_BUFFERED_BYTES / 4));
+    for (let i = 0; i < 5; i++) src.push(chunk + i);
+    await flush();
+
+    const entry = (registry as any).entries.get(CHAT);
+    // A was dropped from the subscriber set on overflow; B (started) remains.
+    expect(entry.subscribers.size).toBe(1);
+    expect(a.frames).toEqual([]); // paused + overflowed: nothing was delivered
+    // B received every frame live (delivery unaffected by A's overflow).
+    expect(b.frames).toHaveLength(5);
+
+    // A's start() (arriving late) degrades to an immediate end, not a partial replay.
+    attA.start();
+    expect(a.frames).toEqual([]);
+    expect(a.ended()).toBe(1);
+  });
+
+  it('open() over a LIVE entry ends started subscribers exactly once and a late done does not touch the new entry (invariant 3)', async () => {
     registry.open(CHAT, 'run-1');
     const src = makePushStream();
     registry.bind(CHAT, 'run-1', 'assist-1', src.stream);
@@ -224,20 +270,23 @@ describe('AiChatStreamRegistryService', () => {
     await flush();
 
     const c = collector();
-    const att = (await registry.attach(CHAT, 'assist-1', 0, c.cb))!;
-    att.start();
+    const att = (await registry.attach(CHAT, false, undefined, c.cb))!;
+    att.start(); // started subscriber on run-1
 
+    // run-2 starts on the same chat while run-1's tee is still reading.
     registry.open(CHAT, 'run-2');
-    expect(c.ended()).toBe(1);
+    expect(c.ended()).toBe(1); // exactly one onEnd from the replace
 
     const newEntry = (registry as any).entries.get(CHAT);
     expect(newEntry.runId).toBe('run-2');
     expect(newEntry.finished).toBe(false);
 
+    // The old tee now completes: its late done must NOT double-end nor delete the
+    // new entry.
     src.push('b');
     src.close();
     await flush();
-    expect(c.ended()).toBe(1);
+    expect(c.ended()).toBe(1); // still exactly one
     const still = (registry as any).entries.get(CHAT);
     expect(still).toBe(newEntry);
     expect(still.runId).toBe('run-2');
@@ -250,6 +299,7 @@ describe('AiChatStreamRegistryService', () => {
     src.push('a');
     await flush();
     const entry = (registry as any).entries.get(CHAT);
+    // Frames were NOT ingested (bind bailed), assistantMessageId untouched.
     expect(entry.frames).toEqual([]);
     expect(entry.assistantMessageId).toBeUndefined();
   });
@@ -260,276 +310,32 @@ describe('AiChatStreamRegistryService', () => {
     const entry = (registry as any).entries.get(CHAT);
     expect(entry.finished).toBe(false);
   });
-});
 
-/**
- * #491 step-stamped retention: the boundary detector, tail-only slicing at the
- * client's frontier N, the confirmed-persist rotation (+ anti-inversion), the
- * overflow gap, the memory bound, and the finished-retained tail. All observable
- * against the REAL registry driven through open/bind/ingest.
- */
-describe('AiChatStreamRegistryService step-aligned retention (#491)', () => {
-  const CHAT = 'chat-s';
-  let registry: AiChatStreamRegistryService;
-
-  beforeEach(() => {
-    registry = new AiChatStreamRegistryService();
-    jest.spyOn((registry as any).logger, 'warn').mockImplementation(() => {});
-  });
-  afterEach(() => registry.onModuleDestroy());
-
-  const entryOf = () => (registry as any).entries.get(CHAT);
-
-  it('stamps frames by finish-step count, aligned with stepsPersisted', async () => {
+  it('a throwing onFrame ejects only that subscriber; the ingest loop stays alive', async () => {
     registry.open(CHAT, 'run-1');
     const src = makePushStream();
     registry.bind(CHAT, 'run-1', 'assist-1', src.stream);
-    // step 0 content, its finish-step, step 1 content, its finish-step, finish.
-    src.push(textDelta('t0', 'a')); // stamp 0
-    src.push(finishStep()); // stamp 0 (the finish-step frame carries the pre value)
-    src.push(textDelta('t1', 'b')); // stamp 1
-    src.push(finishStep()); // stamp 1
-    src.push(finish()); // stamp 2
-    await flush();
-    const e = entryOf();
-    expect(e.stamps).toEqual([0, 0, 1, 1, 2]);
-    expect(e.currentStamp).toBe(2);
-  });
 
-  it('does NOT treat a text delta that merely quotes "finish-step" as a boundary', async () => {
-    registry.open(CHAT, 'run-1');
-    const src = makePushStream();
-    registry.bind(CHAT, 'run-1', 'assist-1', src.stream);
-    // A model that literally types "type":"finish-step" — JSON-escaped in the frame.
-    src.push(textDelta('t0', '"type":"finish-step"'));
-    await flush();
-    expect(entryOf().currentStamp).toBe(0); // no false boundary
-  });
+    const bad = collector();
+    const badAtt = (await registry.attach(CHAT, false, undefined, {
+      onFrame: () => {
+        throw new Error('boom');
+      },
+      onEnd: bad.cb.onEnd,
+    }))!;
+    badAtt.start();
 
-  it('tail-only: attach at N slices frames with stamp >= N', async () => {
-    registry.open(CHAT, 'run-1');
-    const src = makePushStream();
-    registry.bind(CHAT, 'run-1', 'assist-1', src.stream);
-    src.push(textDelta('t0', 'a')); // 0
-    src.push(finishStep()); // 0
-    src.push(textDelta('t1', 'b')); // 1
-    src.push(finishStep()); // 1
-    src.push(textDelta('t2', 'c')); // 2 (in-progress)
+    const good = collector();
+    const goodAtt = (await registry.attach(CHAT, false, undefined, good.cb))!;
+    goodAtt.start();
+
+    src.push('a'); // bad throws on this frame -> ejected
+    src.push('b'); // good still receives both
     await flush();
 
-    const c = collector();
-    // Client persisted 2 steps -> wants the tail from step 2.
-    const att = (await registry.attach(CHAT, 'assist-1', 2, c.cb))!;
-    expect(tail(att.replay)).toEqual([textDelta('t2', 'c')]);
-  });
-
-  it('attach in the MIDDLE of a step (N between finish-steps) slices from that step', async () => {
-    registry.open(CHAT, 'run-1');
-    const src = makePushStream();
-    registry.bind(CHAT, 'run-1', 'assist-1', src.stream);
-    src.push(textDelta('t0', 'a')); // 0
-    src.push(finishStep()); // 0
-    src.push(textDelta('t1', 'b1')); // 1
-    src.push(textDelta('t1', 'b2')); // 1 (still step 1, no finish-step yet)
-    await flush();
-
-    const c = collector();
-    const att = (await registry.attach(CHAT, 'assist-1', 1, c.cb))!;
-    // Step 0's frames are dropped from the tail; the whole in-progress step 1 is kept.
-    expect(tail(att.replay)).toEqual([textDelta('t1', 'b1'), textDelta('t1', 'b2')]);
-  });
-
-  it('rotates the ring ONLY on a confirmed persist (drops stamp < N)', async () => {
-    registry.open(CHAT, 'run-1');
-    const src = makePushStream();
-    registry.bind(CHAT, 'run-1', 'assist-1', src.stream);
-    src.push(textDelta('t0', 'a')); // 0
-    src.push(finishStep()); // 0
-    src.push(textDelta('t1', 'b')); // 1
-    await flush();
-    expect(entryOf().stamps).toEqual([0, 0, 1]);
-
-    // Confirm step 0 persisted (stepsPersisted = 1) -> drop stamp < 1.
-    registry.confirmPersistedStep(CHAT, 'run-1', 1);
-    expect(entryOf().stamps).toEqual([1]);
-    expect(entryOf().persistedFloor).toBe(1);
-  });
-
-  it('persist FAILED but the ring still fits -> attach SUCCEEDS and the tail includes step N', async () => {
-    registry.open(CHAT, 'run-1');
-    const src = makePushStream();
-    registry.bind(CHAT, 'run-1', 'assist-1', src.stream);
-    src.push(textDelta('t0', 'a')); // 0
-    src.push(finishStep()); // 0
-    src.push(textDelta('t1', 'b')); // 1 (step 1's persist FAILED -> no confirm)
-    await flush();
-    // No confirmPersistedStep for step 1: the ring still holds step 1.
-
-    const c = collector();
-    // Client's last successful persist was step 0 -> stepsPersisted = 1.
-    const att = await registry.attach(CHAT, 'assist-1', 1, c.cb);
-    expect(att).not.toBeNull();
-    expect(tail(att!.replay)).toEqual([textDelta('t1', 'b')]); // includes step 1
-  });
-
-  it('persist failed AND the ring overflowed past N -> 204 (coverage gap)', async () => {
-    registry.open(CHAT, 'run-1');
-    const src = makePushStream();
-    registry.bind(CHAT, 'run-1', 'assist-1', src.stream);
-    // Step 0: a fat step that blows past the cap with NO persist confirmation.
-    const big = 'x'.repeat(Math.floor(AI_CHAT_RUN_STREAM_MAX_BUFFER_BYTES / 2));
-    src.push(textDelta('t0', big)); // 0
-    src.push(textDelta('t0', big)); // 0
-    src.push(textDelta('t0', big)); // 0 -> overflow evicts stamp-0 frames
-    await flush();
-    const e = entryOf();
-    expect(e.overflowed).toBe(true);
-    expect(e.bytes).toBeLessThanOrEqual(registry.maxBufferBytes);
-
-    // A client at frontier 0 falls at/below an evicted step -> gap -> null.
-    const c = collector();
-    expect(await registry.attach(CHAT, 'assist-1', 0, c.cb)).toBeNull();
-  });
-
-  it('stale N (client seed lagged behind a rotation) -> 204; after a refetch (larger N) -> success', async () => {
-    registry.open(CHAT, 'run-1');
-    const src = makePushStream();
-    registry.bind(CHAT, 'run-1', 'assist-1', src.stream);
-    src.push(textDelta('t0', 'a')); // 0
-    src.push(finishStep()); // 0
-    src.push(textDelta('t1', 'b')); // 1
-    src.push(finishStep()); // 1
-    src.push(textDelta('t2', 'c')); // 2
-    await flush();
-    // Server confirmed steps 0 and 1 -> rotate away stamp < 2.
-    registry.confirmPersistedStep(CHAT, 'run-1', 2);
-    expect(entryOf().stamps).toEqual([2]);
-
-    // A client whose seed still says stepsPersisted = 1 -> below minStamp -> 204.
-    const stale = collector();
-    expect(await registry.attach(CHAT, 'assist-1', 1, stale.cb)).toBeNull();
-
-    // It refetches (now stepsPersisted = 2) and re-attaches -> success.
-    const fresh = collector();
-    const att = await registry.attach(CHAT, 'assist-1', 2, fresh.cb);
-    expect(att).not.toBeNull();
-    expect(tail(att!.replay)).toEqual([textDelta('t2', 'c')]);
-  });
-
-  it('overflow gap CLEARS once a later persist rotates out the holey steps', async () => {
-    registry.open(CHAT, 'run-1');
-    const src = makePushStream();
-    registry.bind(CHAT, 'run-1', 'assist-1', src.stream);
-    const big = 'x'.repeat(Math.floor(AI_CHAT_RUN_STREAM_MAX_BUFFER_BYTES / 2));
-    src.push(textDelta('t0', big)); // 0
-    src.push(textDelta('t0', big)); // 0
-    src.push(finishStep()); // 0 (still stamp 0)
-    src.push(textDelta('t1', 'small')); // 1
-    src.push(finishStep()); // 1
-    src.push(textDelta('t2', 'c')); // 2
-    await flush();
-    expect(entryOf().overflowed).toBe(true);
-
-    // Late persist confirms steps 0..1 -> rotates out the holey step-0 frames.
-    registry.confirmPersistedStep(CHAT, 'run-1', 2);
-    // A client at frontier 2 is now cleanly covered (the hole was below it).
-    const c = collector();
-    const att = await registry.attach(CHAT, 'assist-1', 2, c.cb);
-    expect(att).not.toBeNull();
-    expect(tail(att!.replay)).toEqual([textDelta('t2', 'c')]);
-  });
-
-  it('finished-retained + N = N_final -> empty tail plus the finish frame', async () => {
-    registry.open(CHAT, 'run-1');
-    const src = makePushStream();
-    registry.bind(CHAT, 'run-1', 'assist-1', src.stream);
-    src.push(textDelta('t0', 'a')); // 0
-    src.push(finishStep()); // 0
-    src.push(finish()); // 1  (N_final = 1)
-    src.close();
-    await flush();
-    // The last step's per-step persist confirmed stepsPersisted = 1.
-    registry.confirmPersistedStep(CHAT, 'run-1', 1);
-
-    const c = collector();
-    const att = (await registry.attach(CHAT, 'assist-1', 1, c.cb))!;
-    expect(att.finished).toBe(true);
-    // Empty step tail; just the finish frame so the client's SDK closes the stream.
-    expect(tail(att.replay)).toEqual([finish()]);
-    // No subscriber registered for a finished run.
-    expect(entryOf().subscribers.size).toBe(0);
-  });
-
-  it('#491 regression (#137/#161 dup): a PARAMETERLESS attach (n=null) to a finished NON-rotated run -> 204, but n=0 still gets the tail', async () => {
-    // A finished, non-rotated run: frames present, coverageFloor 0. A missing `n`
-    // (null — a legacy/parameterless tab that never stripped its transcript) must
-    // 204 -> poll, NOT receive the whole tail it would append (duplicate). A
-    // tail-aware client (n=0 present) still resumes.
-    registry.open(CHAT, 'run-1');
-    const src = makePushStream();
-    registry.bind(CHAT, 'run-1', 'assist-1', src.stream);
-    src.push(textDelta('t0', 'a')); // 0
-    src.push(finishStep()); // 0
-    src.push(finish()); // 1
-    src.close();
-    await flush();
-    // NOT rotated (no confirmPersistedStep) -> stamps[0]=0, coverageFloor=0.
-    // MUTATION-VERIFY: revert the `finished && n === null -> null` gate (default n
-    // to 0) and the parameterless attach below serves the full tail instead of 204.
-    expect(await registry.attach(CHAT, 'assist-1', null, collector().cb)).toBeNull();
-    // A tail-aware client at frontier 0 IS served (the distinction: null != 0).
-    const tailAware = await registry.attach(CHAT, 'assist-1', 0, collector().cb);
-    expect(tailAware).not.toBeNull();
-    expect(tailAware!.finished).toBe(true);
-  });
-
-  it('confirmPersistedStep is monotonic and identity-checked', async () => {
-    registry.open(CHAT, 'run-1');
-    const src = makePushStream();
-    registry.bind(CHAT, 'run-1', 'assist-1', src.stream);
-    src.push(textDelta('t0', 'a'));
-    src.push(finishStep());
-    src.push(textDelta('t1', 'b'));
-    await flush();
-    registry.confirmPersistedStep(CHAT, 'run-1', 1);
-    expect(entryOf().persistedFloor).toBe(1);
-    // A stale lower count is ignored.
-    registry.confirmPersistedStep(CHAT, 'run-1', 0);
-    expect(entryOf().persistedFloor).toBe(1);
-    // A foreign runId is ignored.
-    registry.confirmPersistedStep(CHAT, 'WRONG', 5);
-    expect(entryOf().persistedFloor).toBe(1);
-  });
-
-  it('MEMORY BOUND: 5 parallel marathon runs each stream well past 32MB; each ring stays <= the cap', async () => {
-    const cap = registry.maxBufferBytes;
-    const chats = ['m0', 'm1', 'm2', 'm3', 'm4'];
-    const srcs = chats.map((chat) => {
-      registry.open(chat, `run-${chat}`);
-      const s = makePushStream();
-      registry.bind(chat, `run-${chat}`, `assist-${chat}`, s.stream);
-      return s;
-    });
-    // ~256KB frames; 160 per chat = 40MB streamed each, well past the old 32MB.
-    // Interleave a finish-step every 8 frames so steps advance realistically. No
-    // persist confirmation -> the ONLY thing keeping memory bounded is the cap.
-    const frame = 'y'.repeat(256 * 1024);
-    for (let batch = 0; batch < 20; batch++) {
-      for (let i = 0; i < 8; i++) {
-        for (const s of srcs) s.push(textDelta('t', frame));
-      }
-      for (const s of srcs) s.push(finishStep());
-      await flush(); // drain the pump so queues never hold a whole run
-    }
-    let total = 0;
-    for (const chat of chats) {
-      const e = (registry as any).entries.get(chat);
-      expect(e.bytes).toBeLessThanOrEqual(cap);
-      total += e.bytes;
-    }
-    // Total retained across all 5 runs is bounded by 5x the per-run cap — the old
-    // registry would have retained ~5x40MB = 200MB here.
-    expect(total).toBeLessThanOrEqual(cap * chats.length);
+    const entry = (registry as any).entries.get(CHAT);
+    expect(entry.subscribers.size).toBe(1); // bad ejected, good remains
+    expect(good.frames).toEqual(['a', 'b']);
   });
 });
 
@@ -555,7 +361,7 @@ describe('AiChatStreamRegistryService retention timers', () => {
 
   it('a finished entry is removed after the retention window', () => {
     registry.open(CHAT, 'run-1');
-    registry.abortEntry(CHAT, 'run-1');
+    registry.abortEntry(CHAT, 'run-1'); // finalize -> retention armed
     expect((registry as any).entries.get(CHAT)).toBeDefined();
     jest.advanceTimersByTime(RUN_STREAM_RETAIN_FINISHED_MS + 1);
     expect((registry as any).entries.get(CHAT)).toBeUndefined();
@@ -563,18 +369,20 @@ describe('AiChatStreamRegistryService retention timers', () => {
 
   it('retention deletes ONLY its own entry (invariant 2)', () => {
     registry.open(CHAT, 'run-1');
-    registry.abortEntry(CHAT, 'run-1');
+    registry.abortEntry(CHAT, 'run-1'); // arm retention for entry A
+    // Simulate the race where the key was replaced without clearing A's timer.
     const sentinel = { marker: true };
     (registry as any).entries.set(CHAT, sentinel);
     jest.advanceTimersByTime(RUN_STREAM_RETAIN_FINISHED_MS + 1);
+    // A's timer saw entries.get(CHAT) !== A, so it did NOT delete the successor.
     expect((registry as any).entries.get(CHAT)).toBe(sentinel);
   });
 
   it('open() over a retained entry clears its timer and the successor survives', () => {
     registry.open(CHAT, 'run-1');
-    registry.abortEntry(CHAT, 'run-1');
+    registry.abortEntry(CHAT, 'run-1'); // retained, timer armed
     const clearSpy = jest.spyOn(global, 'clearTimeout');
-    registry.open(CHAT, 'run-2');
+    registry.open(CHAT, 'run-2'); // must clear run-1's retain timer
     expect(clearSpy).toHaveBeenCalled();
     jest.advanceTimersByTime(RUN_STREAM_RETAIN_FINISHED_MS + 1);
     const entry = (registry as any).entries.get(CHAT);

apps/server/src/core/ai-chat/ai-chat.controller.attach.spec.ts

@@ -8,12 +8,10 @@ import { SUBSCRIBER_MAX_BUFFERED_BYTES } from './ai-chat-stream-registry.service
 import type { User, Workspace } from '@docmost/db/types/entity.types';
 
 /**
- * Wiring spec for the #184 phase 1.5 attach endpoint (tail-only #491)
+ * Wiring spec for the #184 phase 1.5 attach endpoint
  * (`GET /ai-chat/runs/:chatId/stream`). Owner-gated via assertOwnedChat; the
- * registry is mocked so this exercises ONLY the controller's tail-write/live/204/
- * cleanup wiring against a fake raw socket. The attach signature is now
- * `(chatId, anchor, n, cb)` — the client hands its persisted step frontier `n`
- * and its assistant row id `anchor`. Constructor order is (aiChatService,
+ * registry is mocked so this exercises ONLY the controller's replay/live/204/
+ * cleanup wiring against a fake raw socket. Constructor order is (aiChatService,
  * aiChatRunService, aiChatRepo, aiChatMessageRepo, aiTranscription, pageRepo,
  * streamRegistry, environment).
  */
@@ -88,8 +86,8 @@ describe('AiChatController attach endpoint (#184 phase 1.5)', () => {
       attach: jest.fn(
         (
           _chatId: string,
+          _live: boolean,
           _anchor: string | undefined,
-          _n: number,
           cb: RunStreamCallbacks,
         ) => {
           capturedCb = cb;
@@ -158,7 +156,7 @@ describe('AiChatController attach endpoint (#184 phase 1.5)', () => {
     expect(res.hijack).not.toHaveBeenCalled();
   });
 
-  it('threads anchor and the numeric frontier n through to the registry', async () => {
+  it('threads expect=live and anchor through to the registry', async () => {
     const { controller, streamRegistry } = makeController({
       chat: owned,
       attachment: null,
@@ -167,8 +165,8 @@ describe('AiChatController attach endpoint (#184 phase 1.5)', () => {
     const { req } = makeReq();
     await controller.attachRunStream(
       'c1',
+      'live',
       'anchor-1',
-      '2',
       req,
       res,
       user,
@@ -176,44 +174,13 @@ describe('AiChatController attach endpoint (#184 phase 1.5)', () => {
     );
     expect(streamRegistry.attach).toHaveBeenCalledWith(
       'c1',
+      true,
       'anchor-1',
-      2, // parsed to a number
       expect.anything(),
     );
   });
 
-  it('#491: an ABSENT/invalid n passes null (not 0) so a finished run 204s (not-tail-aware)', async () => {
-    // Distinguishing a MISSING `n` from `n=0` is the #137/#161 dup guard: a
-    // parameterless/legacy tab must be handed null (-> the registry 204s a finished
-    // run) rather than frontier 0 (which would serve a finished non-rotated run's
-    // whole tail). MUTATION-VERIFY: revert to `Number(n) || 0` and this asserts 0.
-    const { controller, streamRegistry } = makeController({
-      chat: owned,
-      attachment: null,
-    });
-    for (const bad of [undefined, '', 'abc']) {
-      streamRegistry.attach.mockClear();
-      const { res } = makeRawRes();
-      const { req } = makeReq();
-      await controller.attachRunStream(
-        'c1',
-        undefined,
-        bad,
-        req,
-        res,
-        user,
-        workspace,
-      );
-      expect(streamRegistry.attach).toHaveBeenCalledWith(
-        'c1',
-        undefined,
-        null,
-        expect.anything(),
-      );
-    }
-  });
-
-  it('#491: a PRESENT n=0 passes 0 (tail-aware, distinct from absent)', async () => {
+  it('passes expect=false when the query is absent', async () => {
     const { controller, streamRegistry } = makeController({
       chat: owned,
       attachment: null,
@@ -223,7 +190,7 @@ describe('AiChatController attach endpoint (#184 phase 1.5)', () => {
     await controller.attachRunStream(
       'c1',
       undefined,
-      '0',
+      undefined,
       req,
       res,
       user,
@@ -231,8 +198,8 @@ describe('AiChatController attach endpoint (#184 phase 1.5)', () => {
     );
     expect(streamRegistry.attach).toHaveBeenCalledWith(
       'c1',
+      false,
       undefined,
-      0,
       expect.anything(),
     );
   });
@@ -278,8 +245,8 @@ describe('AiChatController attach endpoint (#184 phase 1.5)', () => {
     const { req } = makeReq();
     await controller.attachRunStream(
       'c1',
+      'live',
       'a1',
-      '1',
       req,
       res,
       user,

apps/server/src/core/ai-chat/ai-chat.controller.delta.spec.ts

@@ -1,108 +0,0 @@
-import { ForbiddenException } from '@nestjs/common';
-import { AiChatController } from './ai-chat.controller';
-import type { User, Workspace } from '@docmost/db/types/entity.types';
-
-/**
- * Wiring spec for the #491 delta-poll endpoint (`POST /ai-chat/messages/delta`).
- * Owner-gated via assertOwnedChat (same gate as the other reads), NOT flag-gated.
- * The run fact rides IN the delta response (no separate /run poll). Hand-rolled
- * mocks — no Nest graph, no DB. Constructor order: (aiChatService,
- * aiChatRunService, aiChatRepo, aiChatMessageRepo, aiTranscription, pageRepo).
- */
-describe('AiChatController POST /ai-chat/messages/delta (#491)', () => {
-  const user = { id: 'u1' } as User;
-  const workspace = { id: 'ws1' } as Workspace;
-
-  function makeController(opts: {
-    chat?: unknown;
-    delta?: { rows: unknown[]; cursor: string };
-    run?: unknown;
-  }) {
-    const aiChatRunService = {
-      getLatestForChat: jest.fn().mockResolvedValue(opts.run),
-    };
-    const aiChatRepo = {
-      findById: jest.fn().mockResolvedValue(opts.chat),
-    };
-    const aiChatMessageRepo = {
-      findByChatUpdatedAfter: jest
-        .fn()
-        .mockResolvedValue(opts.delta ?? { rows: [], cursor: 'C1' }),
-    };
-    const controller = new AiChatController(
-      {} as never,
-      aiChatRunService as never,
-      aiChatRepo as never,
-      aiChatMessageRepo as never,
-      {} as never,
-      {} as never,
-    );
-    return { controller, aiChatRunService, aiChatRepo, aiChatMessageRepo };
-  }
-
-  it('owner-gates: a chat the user does not own throws, never reaching the repo', async () => {
-    const { controller, aiChatMessageRepo, aiChatRunService } = makeController({
-      chat: { id: 'c1', creatorId: 'someone-else' },
-    });
-    await expect(
-      controller.getMessagesDelta({ chatId: 'c1' }, user, workspace),
-    ).rejects.toBeInstanceOf(ForbiddenException);
-    expect(aiChatMessageRepo.findByChatUpdatedAfter).not.toHaveBeenCalled();
-    expect(aiChatRunService.getLatestForChat).not.toHaveBeenCalled();
-  });
-
-  it('returns { rows, cursor, run:{id,status} } with the run fact inlined', async () => {
-    const rows = [{ id: 'm1' }];
-    const { controller } = makeController({
-      chat: { id: 'c1', creatorId: 'u1' },
-      delta: { rows, cursor: 'C2' },
-      run: { id: 'r1', status: 'running', error: 'ignored', stepCount: 3 },
-    });
-    const res = await controller.getMessagesDelta(
-      { chatId: 'c1', cursor: 'C1' },
-      user,
-      workspace,
-    );
-    expect(res).toEqual({
-      rows,
-      cursor: 'C2',
-      // ONLY id + status — never the whole run row.
-      run: { id: 'r1', status: 'running' },
-    });
-  });
-
-  it('run is null when the chat has never had a run', async () => {
-    const { controller } = makeController({
-      chat: { id: 'c1', creatorId: 'u1' },
-      run: undefined,
-    });
-    const res = await controller.getMessagesDelta(
-      { chatId: 'c1' },
-      user,
-      workspace,
-    );
-    expect(res.run).toBeNull();
-  });
-
-  it('passes cursor through, defaulting a missing cursor to null (first poll)', async () => {
-    const { controller, aiChatMessageRepo } = makeController({
-      chat: { id: 'c1', creatorId: 'u1' },
-    });
-    await controller.getMessagesDelta({ chatId: 'c1' }, user, workspace);
-    expect(aiChatMessageRepo.findByChatUpdatedAfter).toHaveBeenCalledWith(
-      'c1',
-      'ws1',
-      null,
-    );
-    await controller.getMessagesDelta(
-      { chatId: 'c1', cursor: 'CX' },
-      user,
-      workspace,
-    );
-    expect(aiChatMessageRepo.findByChatUpdatedAfter).toHaveBeenLastCalledWith(
-      'c1',
-      'ws1',
-      'CX',
-    );
-  });
-});

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

@@ -51,7 +51,6 @@ import {
   ChatIdDto,
   ExportChatDto,
   GeneratePageTitleDto,
-  GetChatDeltaDto,
   GetChatMessagesDto,
   GetRunDto,
   RenameChatDto,
@@ -64,47 +63,6 @@ import {
   SUBSCRIBER_MAX_BUFFERED_BYTES,
 } from './ai-chat-stream-registry.service';
 import { startSseHeartbeat } from './sse-resilience';
-
-/**
- * Write the attach TAIL to the hijacked socket in chunks that RESPECT drain
- * (#491): each `write()` that returns false (the kernel buffer is full) is awaited
- * on the next 'drain' before continuing. The old code wrote the whole buffer
- * synchronously, which — with the pre-#491 32MB ring — spiked memory (half the
- * OOM). Bails immediately if the socket ended/errored mid-write. Frames that the
- * paused registry subscriber buffers while this awaits are delivered by start().
- */
-async function writeTailRespectingDrain(
-  raw: {
-    write(chunk: string): boolean;
-    writableEnded?: boolean;
-    destroyed?: boolean;
-    once(event: string, cb: () => void): unknown;
-    removeListener?(event: string, cb: () => void): unknown;
-  },
-  frames: string[],
-): Promise<void> {
-  for (const frame of frames) {
-    if (raw.writableEnded || raw.destroyed) return;
-    const ok = raw.write(frame);
-    if (!ok) {
-      // Kernel buffer full — wait for drain (or an early close/error) before the
-      // next chunk, so a slow reader never forces the whole tail into memory.
-      // Remove ALL three listeners once any fires, so a many-chunk tail with
-      // repeated backpressure never leaks (MaxListenersExceededWarning).
-      await new Promise<void>((resolve) => {
-        const finish = (): void => {
-          raw.removeListener?.('drain', finish);
-          raw.removeListener?.('close', finish);
-          raw.removeListener?.('error', finish);
-          resolve();
-        };
-        raw.once('drain', finish);
-        raw.once('close', finish);
-        raw.once('error', finish);
-      });
-    }
-  }
-}
 import { EnvironmentService } from '../../integrations/environment/environment.service';
 
 /**
@@ -191,46 +149,6 @@ export class AiChatController {
     );
   }
 
-  /**
-   * Delta poll (#491) — the degraded-poll fallback's payload. Returns the chat's
-   * message rows changed since `cursor` (a DB-clock timestamp from the previous
-   * poll), a FRESH cursor, AND the current run fact `{ id, status } | null`. This
-   * replaces the old degraded poll that refetched ALL infinite-query pages (full
-   * parts) every 2.5s: the client seeds once and thereafter merges only the
-   * deltas by id (the overlap window guarantees repeats — the merge is idempotent,
-   * see mergeById). The run fact rides IN the delta (a separate /run poll would
-   * double the poll QPS), so the client FSM gets the run's status on the same tick.
-   * Owner-gated via assertOwnedChat (same gate as the other read endpoints).
-   */
-  @HttpCode(HttpStatus.OK)
-  @Post('messages/delta')
-  async getMessagesDelta(
-    @Body() dto: GetChatDeltaDto,
-    @AuthUser() user: User,
-    @AuthWorkspace() workspace: Workspace,
-  ): Promise<{
-    rows: AiChatMessage[];
-    cursor: string;
-    run: { id: string; status: string } | null;
-  }> {
-    await this.assertOwnedChat(dto.chatId, user, workspace);
-    const { rows, cursor } =
-      await this.aiChatMessageRepo.findByChatUpdatedAfter(
-        dto.chatId,
-        workspace.id,
-        dto.cursor ?? null,
-      );
-    const run = await this.aiChatRunService.getLatestForChat(
-      dto.chatId,
-      workspace.id,
-    );
-    return {
-      rows,
-      cursor,
-      run: run ? { id: run.id, status: run.status } : null,
-    };
-  }
-
   /**
    * Export a chat to Markdown (#183). The DB is the single source of truth: the
    * whole transcript is loaded (oldest -> newest) and rendered server-side. Now
@@ -331,25 +249,19 @@ export class AiChatController {
   }
 
   /**
-   * Attach to a chat's live run stream from the client's step frontier (#184 phase
-   * 1.5, tail-only #491). A late/reloaded tab hands the server the step count it
-   * has PERSISTED (`n` = the seeded row's `metadata.stepsPersisted`) and its
-   * assistant row id (`anchor`); the registry answers with the TAIL past step `n`
-   * (a synthetic `start` frame + the buffered frames stamped >= n) and then the
-   * live tail. Owner-gated via assertOwnedChat (same gate as getRun). When there
-   * is nothing to resume — no entry, a ring that does not cover the client's
-   * frontier (overflow gap, or the client's seed lagged a rotation), or an anchor
-   * that pins a DIFFERENT run (invariant 6) — the endpoint answers 204, the ONLY
-   * "nothing to resume" signal the AI SDK's reconnect accepts (it maps 204 to a
-   * silent no-op); the client then refetches (a larger n) and re-attaches. With
-   * AI_CHAT_RESUMABLE_STREAM off the registry is never populated, so attach always
-   * 204s.
+   * Attach to a chat's live run stream (#184 phase 1.5). A late/reloaded tab
+   * replays the frames buffered so far and then follows the live tail as a normal
+   * streamer. Owner-gated via assertOwnedChat (same gate as getRun). When there is
+   * nothing to resume — no entry, a finished run without expect=live, an
+   * overflowed buffer, or an anchor that pins a DIFFERENT run — the endpoint
+   * answers 204, the ONLY "nothing to resume" signal the AI SDK's reconnect
+   * accepts (it maps 204 to a silent no-op). With AI_CHAT_RESUMABLE_STREAM off the
+   * registry is never populated, so attach always 204s.
    *
-   * The step marker `n` comes ONLY from the client — the server never reads the
-   * row to derive it, because a server-side n from a stale seed would open a
-   * silent one-step hole. The tail is written to the socket in CHUNKS respecting
-   * drain (writeTailRespectingDrain): the old code synchronously blasted the whole
-   * buffer, which — with the old 32MB cap — was half the OOM.
+   * `expect=live` opts into replaying a finished-but-retained run (safe only when
+   * the client stripped the streaming tail); `anchor` is the client's assistant
+   * row id, which must match this run's (invariant 6) or a foreign run's
+   * transcript would be replayed into the store.
    */
   @SkipTransform()
   @UseGuards(JwtAuthGuard, UserThrottlerGuard)
@@ -357,49 +269,39 @@ export class AiChatController {
   @Get('runs/:chatId/stream')
   async attachRunStream(
     @Param('chatId', new ParseUUIDPipe()) chatId: string,
+    @Query('expect') expect: string | undefined,
     @Query('anchor') anchor: string | undefined,
-    @Query('n') n: string | undefined,
     @Req() req: FastifyRequest,
     @Res() res: FastifyReply,
     @AuthUser() user: User,
     @AuthWorkspace() workspace: Workspace,
   ): Promise<void> {
     await this.assertOwnedChat(chatId, user, workspace); // same gate as getRun
-    // The client's persisted step frontier. #491: distinguish a MISSING/invalid `n`
-    // (null — a NOT-tail-aware, legacy/parameterless tab expecting the old
-    // "finished -> 204 -> poll" contract) from `n=0` (a tail-aware client with
-    // nothing persisted yet). Passing 0 for a missing `n` would serve a finished,
-    // non-rotated run's WHOLE tail and a parameterless client would append it onto
-    // the steps it already shows -> #137/#161 duplicate. null makes the registry
-    // 204 such a finished run (see attach); a tail-aware n=0 still resumes.
-    const frontier: number | null =
-      n === undefined || n === '' || !Number.isFinite(Number(n))
-        ? null
-        : Math.max(0, Number(n));
-    // The per-subscriber backpressure cap tracks the (env-tunable) ring cap.
-    const subscriberCap =
-      this.streamRegistry?.subscriberMaxBufferedBytes ??
-      SUBSCRIBER_MAX_BUFFERED_BYTES;
     let stopHeartbeat: () => void = () => undefined;
-    const attachment = await this.streamRegistry?.attach(chatId, anchor, frontier, {
-      onFrame: (frame) => {
-        // Backpressure guard: 2x the ring cap, so the initial tail burst alone
-        // can never trip it; only a genuinely stalled socket can.
-        try {
-          if (res.raw.writableLength > subscriberCap) {
-            res.raw.destroy(); // 'close' fires -> unsubscribe below
-            return;
+    const attachment = await this.streamRegistry?.attach(
+      chatId,
+      expect === 'live',
+      anchor,
+      {
+        onFrame: (frame) => {
+          // Backpressure guard: 2x the replay cap, so the initial replay burst
+          // alone can never trip it; only a genuinely stalled socket can.
+          try {
+            if (res.raw.writableLength > SUBSCRIBER_MAX_BUFFERED_BYTES) {
+              res.raw.destroy(); // 'close' fires -> unsubscribe below
+              return;
+            }
+            if (!res.raw.writableEnded) res.raw.write(frame);
+          } catch {
+            res.raw.destroy();
           }
-          if (!res.raw.writableEnded) res.raw.write(frame);
-        } catch {
-          res.raw.destroy();
-        }
+        },
+        onEnd: () => {
+          stopHeartbeat();
+          if (!res.raw.writableEnded) res.raw.end();
+        },
       },
-      onEnd: () => {
-        stopHeartbeat();
-        if (!res.raw.writableEnded) res.raw.end();
-      },
-    });
+    );
     if (!attachment) {
       res.status(204).send(); // the ONLY "nothing to resume" signal the SDK accepts
       return;
@@ -428,16 +330,13 @@ export class AiChatController {
         // deliberately NO Connection/Keep-Alive (hop-by-hop; Safari/HTTP2)
       });
       res.raw.flushHeaders?.();
-      // Write the tail in chunks respecting drain (not a synchronous blast, which
-      // was half the OOM). Frames the paused subscriber buffers meanwhile are
-      // drained by start() below; its cap is the backstop for a stalled socket.
-      await writeTailRespectingDrain(res.raw, attachment.replay);
+      for (const frame of attachment.replay) res.raw.write(frame);
       if (attachment.finished) {
-        if (!res.raw.writableEnded) res.raw.end();
+        res.raw.end();
         return;
       }
       stopHeartbeat = startSseHeartbeat(res.raw, 15_000);
-      attachment.start(); // drain pending accumulated during the tail write, go live
+      attachment.start(); // drain pending accumulated during replay, go live
     } catch {
       attachment.unsubscribe();
       stopHeartbeat();

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

@@ -181,7 +181,7 @@ describe('AiChatService.stream — abortSignal wiring (#184 F3)', () => {
       {} as never, // pageAccess
       { isAiChatDeferredToolsEnabled: () => false, isAiChatFinalStepLockdownEnabled: () => false } as never, // environment
     );
-    return { svc, aiChatMessageRepo };
+    return { svc };
   }
 
   const body = {
@@ -287,7 +287,7 @@ describe('AiChatService.stream — abortSignal wiring (#184 F3)', () => {
   // Drive stream() to the point streamText is called, capturing the options object
   // (which carries onStepFinish/onFinish/onError/onAbort) and the run hooks.
   async function captureStreamCallbacks() {
-    const { svc, aiChatMessageRepo } = makeService();
+    const { svc } = makeService();
     let capturedOpts: any;
     streamTextMock.mockImplementation((opts: any) => {
       capturedOpts = opts;
@@ -314,7 +314,7 @@ describe('AiChatService.stream — abortSignal wiring (#184 F3)', () => {
       runHooks: runHooks as never,
     });
     expect(capturedOpts).toBeDefined();
-    return { capturedOpts, runHooks, aiChatMessageRepo };
+    return { capturedOpts, runHooks };
   }
 
   it('F9: onStepFinish bumps the run step count, onFinish settles the run "completed" (the dominant autonomous-run path)', async () => {
@@ -369,51 +369,6 @@ describe('AiChatService.stream — abortSignal wiring (#184 F3)', () => {
       expect.stringContaining('provider exploded'),
     );
   });
-
-  // #490 reactive branch: a provider CONTEXT-OVERFLOW 400 in onError is classified,
-  // records a distinguishable cause, and stamps metadata.replayOverflow so the NEXT
-  // turn's budgeter trims aggressively (the recovery that un-bricks the chat).
-  it('#490: a context-overflow 400 stamps replayOverflow on the finalized row', async () => {
-    jest
-      .spyOn(Logger.prototype, 'error')
-      .mockImplementation(() => undefined as never);
-    jest
-      .spyOn(Logger.prototype, 'warn')
-      .mockImplementation(() => undefined as never);
-    const { capturedOpts, aiChatMessageRepo } = await captureStreamCallbacks();
-
-    const overflow = Object.assign(new Error('too large'), {
-      statusCode: 400,
-      message:
-        "This model's maximum context length is 128000 tokens. However, your messages resulted in 214000 tokens. Please reduce the length.",
-    });
-    await capturedOpts.onError({ error: overflow });
-
-    // The seed row exists (finalizeOwner is the owner-write path).
-    expect(aiChatMessageRepo.finalizeOwner).toHaveBeenCalled();
-    const calls = aiChatMessageRepo.finalizeOwner.mock.calls as any[][];
-    const patch = calls[calls.length - 1][2] as {
-      status: string;
-      metadata: Record<string, unknown>;
-    };
-    expect(patch.status).toBe('error');
-    expect(patch.metadata.replayOverflow).toBe(true);
-    expect(patch.metadata.error).toContain('контекстное окно');
-  });
-
-  it('#490: a non-overflow error does NOT stamp replayOverflow', async () => {
-    jest
-      .spyOn(Logger.prototype, 'error')
-      .mockImplementation(() => undefined as never);
-    const { capturedOpts, aiChatMessageRepo } = await captureStreamCallbacks();
-    await capturedOpts.onError({ error: new Error('network reset') });
-    const calls = aiChatMessageRepo.finalizeOwner.mock.calls as any[][];
-    const patch = calls[calls.length - 1][2] as {
-      status: string;
-      metadata: Record<string, unknown>;
-    };
-    expect('replayOverflow' in patch.metadata).toBe(false);
-  });
 });
 
 /**

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

@@ -13,7 +13,6 @@ import {
   compactToolOutput,
   assistantParts,
   serializeSteps,
-  type StepPartsCache,
   rowToUiMessage,
   prepareAgentStep,
   stepBudgetWarning,
@@ -29,14 +28,10 @@ import {
   FINAL_STEP_NUDGE,
   STEP_LIMIT_NO_ANSWER_MARKER,
   OUTPUT_DEGENERATION_ERROR,
-  lastAssistantContextTokens,
-  lastAssistantReplayOverflow,
-  seedActivatedTools,
 } from './ai-chat.service';
 import type { AiChatMessage, Workspace } from '@docmost/db/types/entity.types';
 import { buildSystemPrompt } from './ai-chat.prompt';
 import type { McpClientsService } from './external-mcp/mcp-clients.service';
-import { resolveEffectiveReplayThreshold } from './history-budget';
 
 /**
  * Unit tests for compactToolOutput: the pure helper that shrinks tool outputs
@@ -119,54 +114,6 @@ describe('compactToolOutput', () => {
 describe('assistantParts', () => {
   type AnyPart = Record<string, unknown>;
 
-  // #490 memoization: assistantParts builds each step's parts once and caches
-  // them by the step OBJECT's identity, so a mid-stream flush does not
-  // re-stringify every prior step's (large) output. Observable property: with a
-  // shared cache, the second call over the SAME step object returns the cached
-  // (identical) part array even if the step's underlying output was swapped —
-  // proving the work was memoized, not redone.
-  it('memoizes a step by identity (shared cache => one build per step)', () => {
-    const cache: StepPartsCache = new WeakMap();
-    const step = {
-      text: 'x',
-      toolCalls: [{ toolCallId: 'c1', toolName: 'getPage', input: {} }],
-      toolResults: [{ toolCallId: 'c1', toolName: 'getPage', output: { v: 1 } }],
-    };
-    const first = assistantParts([step], '', cache) as AnyPart[];
-    expect((first.find((p) => p.type === 'tool-getPage')!.output as any).v).toBe(
-      1,
-    );
-    // Swap the output for a NEW value; a re-build would pick it up, a cache hit
-    // keeps the first result.
-    step.toolResults[0] = {
-      toolCallId: 'c1',
-      toolName: 'getPage',
-      output: { v: 2 },
-    };
-    const second = assistantParts([step], '', cache) as AnyPart[];
-    expect((second.find((p) => p.type === 'tool-getPage')!.output as any).v).toBe(
-      1,
-    );
-    // Same cached part objects are reused.
-    expect(second.find((p) => p.type === 'tool-getPage')).toBe(
-      first.find((p) => p.type === 'tool-getPage'),
-    );
-  });
-
-  it('without a cache, each call rebuilds (no stale memo)', () => {
-    const step = {
-      text: 'x',
-      toolCalls: [{ toolCallId: 'c1', toolName: 'getPage', input: {} }],
-      toolResults: [{ toolCallId: 'c1', toolName: 'getPage', output: { v: 1 } }],
-    };
-    const first = assistantParts([step], '') as AnyPart[];
-    step.toolResults[0].output = { v: 2 };
-    const second = assistantParts([step], '') as AnyPart[];
-    expect((second.find((p) => p.type === 'tool-getPage')!.output as any).v).toBe(
-      2,
-    );
-  });
-
   it('emits output-available for a tool-call WITH a paired result', () => {
     const steps = [
       {
@@ -284,320 +231,61 @@ describe('assistantParts', () => {
   });
 });
 
-// #490 trace format v2: per call the trace stores { input } for the call and an
-// OUTCOME element — { ok: true } on success, { error, kind: 'thrown' } on a
-// thrown tool-error, { error, kind: 'interrupted' } on a mid-step abort. The tool
-// OUTPUT is no longer duplicated here (it lives once in metadata.parts).
-describe('serializeSteps (trace v2)', () => {
+describe('serializeSteps', () => {
   it('returns null when there are no calls or results', () => {
     expect(serializeSteps([])).toBeNull();
   });
 
-  it('pairs a successful call with an { ok: true } outcome and NO output', () => {
+  it('flattens calls and results into a compact trace', () => {
     const trace = serializeSteps([
       {
-        toolCalls: [{ toolCallId: 'c1', toolName: 'getPage', input: { id: 'p1' } }],
-        toolResults: [{ toolCallId: 'c1', toolName: 'getPage' }],
+        toolCalls: [{ toolName: 'getPage', input: { id: 'p1' } }],
+        toolResults: [{ toolName: 'getPage', output: { title: 'T' } }],
       },
     ]) as Array<Record<string, unknown>>;
     expect(trace).toHaveLength(2);
     expect(trace[0]).toEqual({ toolName: 'getPage', input: { id: 'p1' } });
-    expect(trace[1]).toEqual({ toolName: 'getPage', ok: true });
-    // The output is NOT stored in the trace any more (dedup: it lives in parts).
-    expect(trace.some((e) => 'output' in e)).toBe(false);
+    expect(trace[1]).toEqual({ toolName: 'getPage', output: { title: 'T' } });
   });
 
-  it('records a THROWN failure with { error, kind: "thrown" }', () => {
+  it('records a THROWN tool failure (tool-error part) with its error message', () => {
     const trace = serializeSteps([
       {
-        toolCalls: [
-          { toolCallId: 'c1', toolName: 'editPageText', input: { id: 'p1' } },
-        ],
+        toolCalls: [{ toolName: 'editPageText', input: { id: 'p1' } }],
         toolResults: [],
         content: [
           {
             type: 'tool-error',
-            toolCallId: 'c1',
             toolName: 'editPageText',
             error: new Error('page is locked'),
           },
         ],
       },
     ]) as Array<Record<string, unknown>>;
+    // The call element is followed by a paired error element (mirroring how a
+    // successful result is appended), so the failure survives in the trace.
     expect(trace).toHaveLength(2);
     expect(trace[0]).toEqual({ toolName: 'editPageText', input: { id: 'p1' } });
     expect(trace[1]).toEqual({
       toolName: 'editPageText',
       error: 'page is locked',
-      kind: 'thrown',
     });
   });
 
-  it('marks an interrupted call (no result, no throw) with kind "interrupted"', () => {
-    const trace = serializeSteps([
-      {
-        toolCalls: [
-          { toolCallId: 'c1', toolName: 'createComment', input: { x: 1 } },
-        ],
-        toolResults: [],
-        content: [],
-      },
-    ]) as Array<Record<string, unknown>>;
-    expect(trace).toHaveLength(2);
-    expect(trace[1]).toEqual({
-      toolName: 'createComment',
-      error: 'Tool call did not complete.',
-      kind: 'interrupted',
-    });
-    // Structurally distinct from a thrown hard-fail so it never inflates an
-    // error-rate scan.
-    expect((trace[1] as { kind: string }).kind).not.toBe('thrown');
-  });
-
-  it('truncates a very long thrown-error message to the tool-output limit', () => {
+  it('truncates a very long tool-error message to the tool-output limit', () => {
     const long = 'x'.repeat(5000);
     const trace = serializeSteps([
       {
-        toolCalls: [{ toolCallId: 'c1', toolName: 'editPageText', input: {} }],
+        toolCalls: [{ toolName: 'editPageText', input: {} }],
         toolResults: [],
-        content: [
-          {
-            type: 'tool-error',
-            toolCallId: 'c1',
-            toolName: 'editPageText',
-            error: long,
-          },
-        ],
+        content: [{ type: 'tool-error', toolName: 'editPageText', error: long }],
       },
     ]) as Array<Record<string, unknown>>;
     const errorText = trace[1].error as string;
+    // Truncated (not the full 5000 chars) and carries the omission marker.
     expect(errorText.length).toBeLessThan(long.length);
     expect(errorText).toContain('chars omitted');
   });
-
-  it('pairs parallel calls in one step with their outcomes by id', () => {
-    const trace = serializeSteps([
-      {
-        toolCalls: [
-          { toolCallId: 'a', toolName: 'getPage', input: {} },
-          { toolCallId: 'b', toolName: 'searchPages', input: {} },
-        ],
-        toolResults: [{ toolCallId: 'b', toolName: 'searchPages' }],
-        content: [
-          { type: 'tool-error', toolCallId: 'a', toolName: 'getPage', error: 'nope' },
-        ],
-      },
-    ]) as Array<Record<string, unknown>>;
-    // call a, outcome a (thrown), call b, outcome b (ok)
-    expect(trace).toHaveLength(4);
-    expect(trace[1]).toEqual({ toolName: 'getPage', error: 'nope', kind: 'thrown' });
-    expect(trace[3]).toEqual({ toolName: 'searchPages', ok: true });
-  });
-});
-
-// #490: every assistant row flushAssistant writes carries the v2 era marker so a
-// dual-shape diagnostic query can branch on the trace shape without inspecting it.
-describe('toolTraceVersion era marker (#490)', () => {
-  it('stamps metadata.toolTraceVersion = 2 on every flushed row', () => {
-    const seed = flushAssistant([], '', 'streaming');
-    expect(seed.metadata.toolTraceVersion).toBe(2);
-    const done = flushAssistant(
-      [
-        {
-          text: 'ok',
-          toolCalls: [{ toolCallId: 'c1', toolName: 'getPage', input: {} }],
-          toolResults: [{ toolCallId: 'c1', toolName: 'getPage' }],
-        },
-      ],
-      '',
-      'completed',
-      { finishReason: 'stop' },
-    );
-    expect(done.metadata.toolTraceVersion).toBe(2);
-  });
-});
-
-// #490 replay-budget signal helpers over persisted history.
-describe('lastAssistantContextTokens', () => {
-  const row = (
-    role: string,
-    metadata: Record<string, unknown> | null,
-  ): AiChatMessage => ({ role, metadata }) as unknown as AiChatMessage;
-
-  it('reads the most recent assistant turn contextTokens (provider fact)', () => {
-    const hist = [
-      row('user', null),
-      row('assistant', { contextTokens: 12000 }),
-      row('user', null),
-      row('assistant', { contextTokens: 41000 }),
-    ];
-    expect(lastAssistantContextTokens(hist)).toBe(41000);
-  });
-
-  it('returns undefined when the last assistant turn recorded no usage', () => {
-    const hist = [row('assistant', { error: 'boom' }), row('user', null)];
-    expect(lastAssistantContextTokens(hist)).toBeUndefined();
-    expect(lastAssistantContextTokens([])).toBeUndefined();
-  });
-});
-
-// #490 snapshotOpenPage fast-path: skip the full Markdown export + upsert when a
-// snapshot already exists at the page's CURRENT version (same updated_at instant).
-describe('snapshotOpenPage fast-path (#490)', () => {
-  function makeSvc(existingSnapshot: unknown, pageUpdatedAt: Date) {
-    const exportPageMarkdown = jest.fn(async () => '# md');
-    const upsert = jest.fn(async () => undefined);
-    const findByChatPage = jest.fn(async () => existingSnapshot);
-    const pageRepo = {
-      findById: jest.fn(async () => ({
-        id: 'p1',
-        workspaceId: 'ws1',
-        updatedAt: pageUpdatedAt,
-      })),
-    };
-    const svc = new AiChatService(
-      {} as never, // ai
-      {} as never, // aiChatRepo
-      {} as never, // aiChatMessageRepo
-      { findByChatPage, upsert } as never, // aiChatPageSnapshotRepo
-      {} as never, // aiSettings
-      { exportPageMarkdown } as never, // tools
-      {} as never, // mcpClients
-      {} as never, // aiAgentRoleRepo
-      pageRepo as never, // pageRepo
-      {} as never, // pageAccess
-      {} as never, // environment
-    );
-    return { svc, exportPageMarkdown, upsert, findByChatPage };
-  }
-
-  const args = () =>
-    [
-      'chat1',
-      'p1',
-      { id: 'ws1' } as never,
-      { id: 'u1' } as never,
-      'sess',
-    ] as const;
-
-  it('skips export + upsert when the snapshot is already at this page version', async () => {
-    const t = new Date('2026-07-07T10:00:00Z');
-    const { svc, exportPageMarkdown, upsert } = makeSvc(
-      { pageUpdatedAt: t, contentMd: '# md' },
-      t,
-    );
-    await (svc as unknown as { snapshotOpenPage: (...a: unknown[]) => Promise<void> })
-      .snapshotOpenPage(...args());
-    expect(exportPageMarkdown).not.toHaveBeenCalled();
-    expect(upsert).not.toHaveBeenCalled();
-  });
-
-  it('exports + upserts when the page advanced since the snapshot', async () => {
-    const { svc, exportPageMarkdown, upsert } = makeSvc(
-      { pageUpdatedAt: new Date('2026-07-07T10:00:00Z'), contentMd: 'old' },
-      new Date('2026-07-07T11:00:00Z'),
-    );
-    await (svc as unknown as { snapshotOpenPage: (...a: unknown[]) => Promise<void> })
-      .snapshotOpenPage(...args());
-    expect(exportPageMarkdown).toHaveBeenCalledTimes(1);
-    expect(upsert).toHaveBeenCalledTimes(1);
-  });
-
-  it('seeds (exports + upserts) on the first turn (no snapshot yet)', async () => {
-    const { svc, exportPageMarkdown, upsert } = makeSvc(
-      undefined,
-      new Date('2026-07-07T10:00:00Z'),
-    );
-    await (svc as unknown as { snapshotOpenPage: (...a: unknown[]) => Promise<void> })
-      .snapshotOpenPage(...args());
-    expect(exportPageMarkdown).toHaveBeenCalledTimes(1);
-    expect(upsert).toHaveBeenCalledTimes(1);
-  });
-});
-
-// #490 deferred-tool activation persisted across turns.
-describe('seedActivatedTools', () => {
-  const valid = new Set(['Search_web', 'getPageJson', 'diffPageVersions']);
-
-  it('seeds from persisted metadata, intersected with current valid names', () => {
-    expect(
-      seedActivatedTools(
-        { activatedTools: ['Search_web', 'getPageJson'] },
-        valid,
-      ),
-    ).toEqual(['Search_web', 'getPageJson']);
-  });
-
-  it('drops a stored tool that is no longer valid (allowlist/role changed)', () => {
-    // 'Habr_publish' was activated before but is not in the current allowlist.
-    expect(
-      seedActivatedTools({ activatedTools: ['Search_web', 'Habr_publish'] }, valid),
-    ).toEqual(['Search_web']);
-  });
-
-  it('is empty/robust for missing, non-array, or unknown-shaped metadata', () => {
-    expect(seedActivatedTools(undefined, valid)).toEqual([]);
-    expect(seedActivatedTools({}, valid)).toEqual([]);
-    expect(seedActivatedTools({ activatedTools: 'nope' }, valid)).toEqual([]);
-    expect(
-      seedActivatedTools({ activatedTools: [1, 'getPageJson', null] }, valid),
-    ).toEqual(['getPageJson']);
-  });
-
-  it('de-duplicates stored names', () => {
-    expect(
-      seedActivatedTools(
-        { activatedTools: ['getPageJson', 'getPageJson'] },
-        valid,
-      ),
-    ).toEqual(['getPageJson']);
-  });
-});
-
-describe('lastAssistantReplayOverflow', () => {
-  const row = (
-    role: string,
-    metadata: Record<string, unknown> | null,
-  ): AiChatMessage => ({ role, metadata }) as unknown as AiChatMessage;
-
-  it('is true only when the LAST assistant turn overflowed', () => {
-    expect(
-      lastAssistantReplayOverflow([
-        row('assistant', { replayOverflow: true }),
-        row('user', null),
-      ]),
-    ).toBe(true);
-    // A recovered (later, non-overflow) assistant turn clears it.
-    expect(
-      lastAssistantReplayOverflow([
-        row('assistant', { replayOverflow: true }),
-        row('user', null),
-        row('assistant', { contextTokens: 5 }),
-      ]),
-    ).toBe(false);
-    expect(lastAssistantReplayOverflow([])).toBe(false);
-  });
-
-  // #490 reactive recovery: a prior turn stamped `replayOverflow` must make the
-  // NEXT turn's effective budget the AGGRESSIVE 0.5x cut — that harder trim is
-  // what un-bricks a chat that just 400'd on the context window. This exercises
-  // the exact wiring the service uses: read the stamp, then scale the threshold.
-  it('#490: a prior replayOverflow drives the next turn to the 0.5x aggressive budget', () => {
-    const history = [
-      row('assistant', { replayOverflow: true }),
-      row('user', null),
-    ];
-    const priorOverflowed = lastAssistantReplayOverflow(history);
-    expect(priorOverflowed).toBe(true);
-    // Base budget 100k -> aggressive recovery halves it to 50k this turn.
-    expect(resolveEffectiveReplayThreshold(100_000, priorOverflowed)).toBe(50_000);
-    // Odd base floors, not rounds.
-    expect(resolveEffectiveReplayThreshold(99_999, true)).toBe(49_999);
-    // No prior overflow -> the base budget is used verbatim (no aggressive cut).
-    expect(resolveEffectiveReplayThreshold(100_000, false)).toBe(100_000);
-    // An explicit off-switch (null) is never overridden, even on recovery.
-    expect(resolveEffectiveReplayThreshold(null, true)).toBeNull();
-  });
 });
 
 describe('rowToUiMessage', () => {
@@ -930,23 +618,6 @@ describe('flushAssistant', () => {
     expect(flushed.metadata.error).toBe('boom');
   });
 
-  // #490 observability: the replay budgeter's decision is stamped on the turn.
-  it('records replayTrimmedToTokens + replayOverflow when provided', () => {
-    const f = flushAssistant([], '', 'error', {
-      error: 'ctx',
-      replayTrimmedToTokens: 42_000,
-      replayOverflow: true,
-    });
-    expect(f.metadata.replayTrimmedToTokens).toBe(42_000);
-    expect(f.metadata.replayOverflow).toBe(true);
-  });
-
-  it('omits the replay metadata when not provided', () => {
-    const f = flushAssistant([], '', 'completed', { finishReason: 'stop' });
-    expect('replayTrimmedToTokens' in f.metadata).toBe(false);
-    expect('replayOverflow' in f.metadata).toBe(false);
-  });
-
   // #274 observability: the page-change diff the agent saw this turn is persisted
   // to metadata.pageChanged when a non-empty diff was injected, and omitted when
   // the diff is empty/whitespace or the arg is not supplied.

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

@@ -55,12 +55,6 @@ import {
   type SelectionContext,
 } from './tools/current-page.util';
 import { roleModelOverride } from './roles/role-model-config';
-import {
-  resolveReplayBudget,
-  resolveEffectiveReplayThreshold,
-  isContextOverflowError,
-  trimHistoryForReplay,
-} from './history-budget';
 import {
   startSseHeartbeat,
   stripStreamingHopByHopHeaders,
@@ -133,15 +127,6 @@ const STEP_LIMIT_NO_ANSWER_MARKER =
 const OUTPUT_DEGENERATION_ERROR =
   'Output degeneration detected (repeated token loop)';
 
-// Prefix recorded on the assistant row when the provider rejected the turn for
-// CONTEXT OVERFLOW (#490): the replayed history exceeded the model's window. The
-// row is ALSO stamped `metadata.replayOverflow` so the NEXT turn's budgeter trims
-// aggressively (the reactive recovery — the overflowing turn had no usage signal
-// to trigger preventive trimming, so the classified 400 is what un-bricks it).
-export const CONTEXT_OVERFLOW_ERROR_PREFIX =
-  'Диалог превысил контекстное окно модели; история будет агрессивно ' +
-  'сокращена на следующем ходу.';
-
 /**
  * Compute the step-budget warning text (#444), or '' when this step is outside
  * the warning band. The warning fires on steps
@@ -897,21 +882,6 @@ export class AiChatService implements OnModuleInit, OnModuleDestroy {
       const freshPage = await this.pageRepo.findById(pageId);
       // Page deleted during the turn (or somehow foreign) => don't write.
       if (!freshPage || freshPage.workspaceId !== workspace.id) return;
-      // Fast-path (#490): if a snapshot already exists at THIS page version
-      // (same updated_at instant), its content is already current — skip the full
-      // Markdown export + upsert entirely. A turn that did NOT touch the open page
-      // (the common case) thus does no snapshot work. This mirrors the read-side
-      // fast path in detectPageChange (sameInstant): both trust that a page edit
-      // bumps updated_at. When the agent (or a human) DID edit the page this turn,
-      // updated_at advanced, so this does not match and we re-export as before.
-      const existing = await this.aiChatPageSnapshotRepo.findByChatPage(
-        chatId,
-        pageId,
-        workspace.id,
-      );
-      if (existing && sameInstant(existing.pageUpdatedAt, freshPage.updatedAt)) {
-        return;
-      }
       const currentMd = await this.tools.exportPageMarkdown(
         user,
         sessionId,
@@ -951,17 +921,10 @@ export class AiChatService implements OnModuleInit, OnModuleDestroy {
     // supplied or the supplied one does not belong to this workspace.
     let isNewChat = false;
     let chatId = body.chatId;
-    // Persisted chat-level metadata bag (#490): read once here so the deferred-tool
-    // activation set can be seeded from the previous turn. Undefined for a new chat.
-    let chatMetadata: Record<string, unknown> | undefined;
     if (chatId) {
       const existing = await this.aiChatRepo.findById(chatId, workspace.id);
       if (!existing) {
         chatId = undefined;
-      } else {
-        chatMetadata = (existing.metadata ?? undefined) as
-          | Record<string, unknown>
-          | undefined;
       }
     }
     // The open page the client sent is attacker-controllable — BOTH its id and
@@ -1123,7 +1086,7 @@ export class AiChatService implements OnModuleInit, OnModuleDestroy {
       // per-row conversion and degraded to plain text with a "[tool context
       // omitted]" marker rather than 500-ing the whole turn (silent loss of tool
       // context is not acceptable — the model must see the truncation).
-      let messages = await convertHistoryResilient(uiMessages, (index, err) =>
+      const messages = await convertHistoryResilient(uiMessages, (index, err) =>
         this.logger.warn(
           `Degraded unconvertible history row ${index} on chat ${chatId} to text: ${
             err instanceof Error ? err.message : 'unknown error'
@@ -1172,56 +1135,6 @@ export class AiChatService implements OnModuleInit, OnModuleDestroy {
       // Here we only need the admin-configured system prompt.
       const resolved = await this.aiSettings.resolve(workspace.id);
 
-      // History-replay token budget (#490). The full conversation is replayed to
-      // the provider every turn, so a long chat eventually 400s on the context
-      // window — forever. Bound the REPLAYED history (never the persisted rows).
-      // PRIMARY signal is the provider's own fact: the last turn's contextTokens.
-      const replayBudget = resolveReplayBudget(resolved?.chatContextWindowRaw);
-      if (replayBudget.usedDefault) {
-        // The default fires precisely for installs with NO configured window —
-        // the ones that hit terminal overflow. Warn so it is observable.
-        this.logger.warn(
-          `AI chat (chat ${chatId}): no chatContextWindow configured; ` +
-            `applying the default replay budget (${replayBudget.thresholdTokens} tokens).`,
-        );
-      }
-      // Last turn's provider-reported context size (authoritative when present).
-      const priorContextTokens = lastAssistantContextTokens(oldHistory);
-      // Reactive recovery (#490): if the LAST turn was rejected for context
-      // overflow (stamped by onError), trim AGGRESSIVELY this turn — the
-      // overflowing turn produced no usage signal, so a normal-threshold trim may
-      // not shrink enough to fit. This is what un-bricks a chat that just 400'd.
-      const priorOverflowed = lastAssistantReplayOverflow(oldHistory);
-      const effectiveThreshold = resolveEffectiveReplayThreshold(
-        replayBudget.thresholdTokens,
-        priorOverflowed,
-      );
-      if (priorOverflowed) {
-        this.logger.warn(
-          `AI chat (chat ${chatId}): previous turn hit context overflow; ` +
-            `applying aggressive replay budget (${effectiveThreshold} tokens).`,
-        );
-      }
-      const preTrim = trimHistoryForReplay(
-        messages,
-        effectiveThreshold,
-        // A prior OVERFLOW means the provider count is stale/absent — force the
-        // char-estimate path by ignoring priorContextTokens on recovery.
-        priorOverflowed ? undefined : priorContextTokens,
-      );
-      messages = preTrim.messages;
-      // Observability (#490): record the budgeter's decision on the turn so the UI
-      // can surface "replay truncated at N tokens". Threaded into flushAssistant.
-      let replayTrimmedToTokens: number | undefined = preTrim.trimmed
-        ? preTrim.estimatedTokens
-        : undefined;
-      if (preTrim.trimmed) {
-        this.logger.log(
-          `AI chat (chat ${chatId}): replay history trimmed to ~${preTrim.estimatedTokens} ` +
-            `tokens (budget ${replayBudget.thresholdTokens}).`,
-        );
-      }
-
       // Build the external MCP toolset FIRST so the system prompt can carry each
       // connected server's admin-authored guidance (#180). Merge in admin-
       // configured external MCP tools (web search, etc.; §6.8). A down/slow
@@ -1413,19 +1326,10 @@ export class AiChatService implements OnModuleInit, OnModuleDestroy {
       //    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)),
       );
-      // #490: seed the activation set from the chat's PERSISTED set so the model
-      // does not re-run loadTools every turn to re-activate the same tools. Only
-      // when deferred loading is enabled, and ALWAYS intersected with the CURRENT
-      // valid deferred names — an allowlist/role change must never resurrect a tool
-      // that no longer exists (prepareAgentStep would get a phantom active name).
-      const activatedTools = new Set<string>(
-        deferredEnabled
-          ? seedActivatedTools(chatMetadata, validDeferredNames)
-          : [],
-      );
       // Add the loadTools meta-tool ONLY when the feature is enabled; when off the
       // toolset and behavior are exactly as before.
       const tools = deferredEnabled
@@ -1435,39 +1339,6 @@ export class AiChatService implements OnModuleInit, OnModuleDestroy {
           }
         : baseTools;
 
-      // #490: persist the (deterministically ordered) activation set back onto the
-      // chat metadata at turn end, so the NEXT turn seeds from it. Once-guarded and
-      // skipped when nothing new was activated (the set equals its seed) so an
-      // ordinary turn adds no extra write. Preserves other metadata keys.
-      let activatedToolsPersisted = false;
-      const persistActivatedTools = async (): Promise<void> => {
-        if (!deferredEnabled || activatedToolsPersisted || !chatId) return;
-        activatedToolsPersisted = true;
-        const current = [...activatedTools].sort();
-        const seeded = seedActivatedTools(chatMetadata, validDeferredNames).sort();
-        if (current.length === 0 || current.join('') === seeded.join('')) {
-          return; // nothing new activated -> no write
-        }
-        try {
-          await this.aiChatRepo.update(
-            chatId,
-            {
-              metadata: {
-                ...(chatMetadata ?? {}),
-                activatedTools: current,
-              },
-            } as never,
-            workspace.id,
-          );
-        } catch (err) {
-          this.logger.warn(
-            `Failed to persist activated tools (chat ${chatId}): ${
-              err instanceof Error ? err.message : 'unknown error'
-            }`,
-          );
-        }
-      };
-
       // 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
       // callbacks don't hand us the in-progress text. `capturedSteps` holds finished
@@ -1476,11 +1347,6 @@ export class AiChatService implements OnModuleInit, OnModuleDestroy {
       const capturedSteps: StepLike[] = [];
       let inProgressText = '';
 
-      // Per-turn step->parts memo (#490): shared across every flushAssistant call
-      // this turn so each finished step's (large) output is JSON-stringified ONCE,
-      // not re-stringified on every subsequent onStepFinish flush (was O(N²)).
-      const partsCache: StepPartsCache = new WeakMap();
-
       // Token-degeneration guard (#444). When the final-step lockdown is OFF, a
       // runaway repetition loop (the 255KB "loadTools." incident) is aborted via
       // this internal controller, unioned with the run/socket signal below. The
@@ -1538,39 +1404,27 @@ export class AiChatService implements OnModuleInit, OnModuleDestroy {
       // Per-step (non-terminal) update: persist the finished steps the moment a
       // step ends. Tolerant — a failed update is logged and swallowed so it never
       // throws into the stream. Keeps status 'streaming'.
-      //
-      // #491: it now SIGNALS its outcome — the persisted `stepsPersisted` count on
-      // a CONFIRMED write, or null when it was skipped/failed. The caller rotates
-      // the run-stream registry ring ONLY on a non-null return (a confirmed
-      // persist), so a failed persist never rotates away a step nobody has (the
-      // classic inversion bug); a failure just makes the ring cover more.
-      const updateStreaming = async (): Promise<number | null> => {
-        if (!assistantId) return null;
+      const updateStreaming = async (): Promise<void> => {
+        if (!assistantId) return;
         // Cheap short-circuit once the turn is finalized (see `finalized` below).
         // The AUTHORITATIVE guard is `onlyIfStreaming` on the UPDATE: a late
         // fire-and-forget step update could still be in flight on another pool
         // connection when finalize runs, so the SQL `WHERE status='streaming'`
         // (not this flag) is what prevents it clobbering the terminal row.
-        if (finalized) return null;
-        // Build the flush ONCE so the returned count is EXACTLY the persisted
-        // `stepsPersisted` (both derive from capturedSteps.length at this instant).
-        const flushed = flushAssistant(capturedSteps, '', 'streaming', {
-          pageChanged,
-          partsCache,
-        });
-        const stepsPersisted = flushed.metadata.stepsPersisted as number;
+        if (finalized) return;
         try {
-          await this.aiChatMessageRepo.update(assistantId, workspace.id, flushed, {
-            onlyIfStreaming: true,
-          });
-          return stepsPersisted;
+          await this.aiChatMessageRepo.update(
+            assistantId,
+            workspace.id,
+            flushAssistant(capturedSteps, '', 'streaming', { pageChanged }),
+            { onlyIfStreaming: true },
+          );
         } catch (err) {
           this.logger.warn(
             `Failed to update streaming assistant row: ${
               err instanceof Error ? err.message : 'unknown error'
             }`,
           );
-          return null;
         }
       };
 
@@ -1739,24 +1593,7 @@ export class AiChatService implements OnModuleInit, OnModuleDestroy {
             // this point still recovers the step. Not awaited here (never block the
             // stream), but SERIALIZED via stepUpdateChain so the writes commit in
             // step order; updateStreaming is error-tolerant (logs + swallows).
-            // #491: on a CONFIRMED persist, rotate the run-stream registry ring to
-            // drop the now-on-disk steps (stamp < stepsPersisted). Gated on the
-            // resumable flag (same as open/bind) and identity-checked in the
-            // registry; a null return (skipped/failed) rotates NOTHING (auto-safe).
-            stepUpdateChain = stepUpdateChain.then(async () => {
-              const persisted = await updateStreaming();
-              if (
-                persisted != null &&
-                runId &&
-                this.environment?.isAiChatResumableStreamEnabled?.()
-              ) {
-                this.streamRegistry?.confirmPersistedStep(
-                  chatId,
-                  runId,
-                  persisted,
-                );
-              }
-            });
+            stepUpdateChain = stepUpdateChain.then(() => updateStreaming());
             // #184: persist the run's progress (finished-step count). Fire-and-
             // forget; the hook swallows its own errors.
             if (runId) runHooks?.onStep?.(runId, capturedSteps.length);
@@ -1812,8 +1649,6 @@ export class AiChatService implements OnModuleInit, OnModuleDestroy {
                 // closure scope here). Omitted/0 = no limit.
                 maxContextTokens: resolved?.chatContextWindow,
                 pageChanged,
-                partsCache,
-                replayTrimmedToTokens,
               }),
             );
             // #184/#487: the RUN is finalized ALWAYS (never gated on the message).
@@ -1838,8 +1673,6 @@ export class AiChatService implements OnModuleInit, OnModuleDestroy {
             // own edits are baked in — and this also SEEDS the snapshot on the first
             // turn. Runs once across every terminal path (see snapshotTurnEnd).
             await snapshotTurnEnd();
-            // #490: persist the deferred-tool activation set for the next turn.
-            await persistActivatedTools();
 
             // Generate the chat title for a freshly created chat AFTER the stream's
             // provider call has completed — NOT concurrently with it. The z.ai coding
@@ -1863,16 +1696,7 @@ export class AiChatService implements OnModuleInit, OnModuleDestroy {
             // object, so the actual provider cause is clearly logged. Reuse the
             // shared formatter so provider error formatting stays unified.
             const e = error as { stack?: string };
-            // #490 reactive branch: classify a CONTEXT-OVERFLOW rejection (the
-            // replayed history exceeded the model window). The overflowing turn had
-            // no prior usage to trigger preventive trimming, so we record a clear,
-            // distinguishable cause AND stamp the row so the NEXT turn's budgeter
-            // trims aggressively — the reactive recovery that un-bricks the chat.
-            const overflow = isContextOverflowError(error);
-            const providerError = describeProviderError(error, String(error));
-            const errorText = overflow
-              ? `${CONTEXT_OVERFLOW_ERROR_PREFIX} (${providerError})`
-              : providerError;
+            const errorText = describeProviderError(error, String(error));
             this.logger.error(`AI chat stream error: ${errorText}`, e?.stack);
             // DIAGNOSTIC (Safari stream-drop investigation) — temporary: timing of
             // an error-terminated stream.
@@ -1890,9 +1714,6 @@ export class AiChatService implements OnModuleInit, OnModuleDestroy {
               flushAssistant(capturedSteps, inProgressText, 'error', {
                 error: errorText,
                 pageChanged,
-                partsCache,
-                replayTrimmedToTokens,
-                replayOverflow: overflow || undefined,
               }),
             );
             // #184: settle the RUN as failed, carrying the provider/transport cause.
@@ -1902,8 +1723,6 @@ export class AiChatService implements OnModuleInit, OnModuleDestroy {
             // committed before the error must be baked into the snapshot, or the
             // next turn would mis-report it as a user edit.
             await snapshotTurnEnd();
-            // #490: persist the deferred-tool activation set for the next turn.
-            await persistActivatedTools();
           },
           onAbort: async ({ steps }) => {
             // #444: distinguish a degeneration abort (our internal controller) from
@@ -1918,7 +1737,6 @@ export class AiChatService implements OnModuleInit, OnModuleDestroy {
                 flushAssistant(capturedSteps, truncated, 'error', {
                   error: OUTPUT_DEGENERATION_ERROR,
                   pageChanged,
-                  partsCache,
                 }),
               );
               if (runId)
@@ -1929,8 +1747,6 @@ export class AiChatService implements OnModuleInit, OnModuleDestroy {
                 );
               await closeExternalClients();
               await snapshotTurnEnd();
-              // #490: persist the deferred-tool activation set for the next turn.
-              await persistActivatedTools();
               return;
             }
             const partialChars =
@@ -1955,7 +1771,6 @@ export class AiChatService implements OnModuleInit, OnModuleDestroy {
             await finalizeAssistant(
               flushAssistant(capturedSteps, inProgressText, 'aborted', {
                 pageChanged,
-                partsCache,
               }),
             );
             // #184: settle the RUN as aborted (an explicit user stop reached the
@@ -1966,8 +1781,6 @@ export class AiChatService implements OnModuleInit, OnModuleDestroy {
             // committed before the client disconnect / stop() must be baked into the
             // snapshot, or the next turn would mis-report it as a user edit.
             await snapshotTurnEnd();
-            // #490: persist the deferred-tool activation set for the next turn.
-            await persistActivatedTools();
           },
         });
 
@@ -2278,70 +2091,6 @@ export function chatStreamMetadata(
   return undefined;
 }
 
-/**
- * The provider-reported context size of the most recent assistant turn, read from
- * its persisted `metadata.contextTokens` (#490 replay budgeter's PRIMARY signal —
- * the provider's own fact, not an estimate). Returns undefined for a chat with no
- * assistant turn yet, or one whose last turn recorded no usage (e.g. it errored),
- * in which case the budgeter falls back to the char-estimate.
- */
-export function lastAssistantContextTokens(
-  history: ReadonlyArray<AiChatMessage>,
-): number | undefined {
-  for (let i = history.length - 1; i >= 0; i--) {
-    const row = history[i];
-    if (row.role !== 'assistant') continue;
-    const meta = (row.metadata ?? {}) as { contextTokens?: unknown };
-    const n = meta.contextTokens;
-    return typeof n === 'number' && Number.isFinite(n) && n > 0 ? n : undefined;
-  }
-  return undefined;
-}
-
-/**
- * Seed the per-turn deferred-tool activation set from a chat's persisted metadata
- * (#490), INTERSECTED with the current valid deferred names. Persisting the set
- * across turns saves the model re-running loadTools every turn to re-activate the
- * same tools; intersecting on load means a changed allowlist / role can never
- * resurrect a tool that no longer exists (which would hand prepareAgentStep a
- * phantom active name). Tolerant of any stored shape — a non-array is ignored.
- */
-export function seedActivatedTools(
-  metadata: Record<string, unknown> | undefined,
-  validDeferredNames: ReadonlySet<string>,
-): string[] {
-  const stored = metadata?.activatedTools;
-  if (!Array.isArray(stored)) return [];
-  const seen = new Set<string>();
-  const out: string[] = [];
-  for (const name of stored) {
-    if (typeof name === 'string' && validDeferredNames.has(name) && !seen.has(name)) {
-      seen.add(name);
-      out.push(name);
-    }
-  }
-  return out;
-}
-
-/**
- * Whether the most recent assistant turn was rejected for CONTEXT OVERFLOW
- * (#490): its row carries `metadata.replayOverflow` (stamped by the stream's
- * onError). The next turn's budgeter reads this to trim aggressively — the
- * reactive recovery. Only the LAST assistant turn matters (an older overflow was
- * already recovered), so we stop at the first assistant row scanning backwards.
- */
-export function lastAssistantReplayOverflow(
-  history: ReadonlyArray<AiChatMessage>,
-): boolean {
-  for (let i = history.length - 1; i >= 0; i--) {
-    const row = history[i];
-    if (row.role !== 'assistant') continue;
-    const meta = (row.metadata ?? {}) as { replayOverflow?: unknown };
-    return meta.replayOverflow === true;
-  }
-  return false;
-}
-
 /** The last message with role 'user' from a useChat payload, if any. */
 function lastUserMessage(
   messages: UIMessage[] | undefined,
@@ -2403,15 +2152,6 @@ export function sanitizeUserParts(
 /** Marker for a history row whose tool parts could not be replayed (#489). */
 export const TOOL_CONTEXT_OMITTED_MARKER = '[tool context omitted]';
 
-/**
- * Synthetic error text for a tool call that neither returned a result nor threw
- * a `tool-error` — i.e. it was interrupted mid-step (an abort / server restart).
- * Shared by `assistantParts` (the replayed `output-error` part) and
- * `serializeSteps` (the `{ kind: 'interrupted' }` trace element) so the replay
- * text and the trace stay in lockstep (#490).
- */
-export const TOOL_CALL_INCOMPLETE_TEXT = 'Tool call did not complete.';
-
 /**
  * Convert persisted UI history to model messages, tolerating a single poisoned
  * row (#489). `convertToModelMessages` over the WHOLE array throws if ANY row is
@@ -2619,97 +2359,71 @@ function normalizeToolError(error: unknown): string {
  */
 // Exported only so the unit tests can import these pure helpers; exporting
 // them does not change runtime behavior.
-/**
- * Per-turn memo for {@link assistantParts}: a step's rebuilt parts keyed by the
- * step OBJECT's identity (#490). A finished step in `capturedSteps` keeps a stable
- * reference across every mid-stream flush, and `compactToolOutput` inside it does a
- * `JSON.stringify` of the whole (often 50–200 KB) output — so without a memo each
- * `onStepFinish` re-stringifies EVERY prior step's output (O(N²) stringify over a
- * turn). Keyed by step identity => one stringify per step per turn. WeakMap so a
- * turn's steps are GC'd with the turn.
- */
-export type StepPartsCache = WeakMap<object, Array<Record<string, unknown>>>;
-
-/** Build the parts for ONE step (text + a part per tool call). Pure. */
-function buildStepParts(step: StepLike): Array<Record<string, unknown>> {
-  const parts: Array<Record<string, unknown>> = [];
-  if (step.text) {
-    parts.push({ type: 'text', text: step.text });
-  }
-  // Index this step's results by tool call id to pair calls with outputs.
-  const resultsById = new Map<string, unknown>();
-  for (const r of step.toolResults ?? []) {
-    if (r.toolCallId) resultsById.set(r.toolCallId, r.output);
-  }
-  // Index this step's THROWN tool failures (ai@6 `tool-error` content parts)
-  // by tool call id, so a call that failed replays with its real error text.
-  const errorsById = new Map<string, unknown>();
-  for (const part of step.content ?? []) {
-    if (part.type === 'tool-error' && part.toolCallId) {
-      errorsById.set(part.toolCallId, part.error);
-    }
-  }
-  for (const call of step.toolCalls ?? []) {
-    if (!call.toolName || !call.toolCallId) continue;
-    const hasResult = resultsById.has(call.toolCallId);
-    if (hasResult) {
-      // output-available: the tool returned; the next turn replays its result.
-      parts.push({
-        type: `tool-${call.toolName}`,
-        toolCallId: call.toolCallId,
-        state: 'output-available',
-        input: call.input,
-        output: compactToolOutput(resultsById.get(call.toolCallId)),
-      });
-    } else if (errorsById.has(call.toolCallId)) {
-      // The tool THREW: replay the REAL error so the model on the next turn
-      // knows WHY the call failed (and does not blindly repeat it). An
-      // output-error round-trips through convertToModelMessages as a balanced
-      // tool-call + tool-result, keeping the rebuilt history valid.
-      parts.push({
-        type: `tool-${call.toolName}`,
-        toolCallId: call.toolCallId,
-        state: 'output-error',
-        input: call.input,
-        errorText: normalizeToolError(errorsById.get(call.toolCallId)),
-      });
-    } else {
-      // No paired result AND no tool-error (e.g. aborted mid-step). Persisting
-      // a bare tool-call (input-available) would replay as an unpaired call and
-      // throw MissingToolResultsError on the next turn (convertToModelMessages
-      // emits no tool-result for it). Emit a SYNTHETIC paired result instead:
-      // an output-error round-trips through convertToModelMessages as a
-      // balanced tool-call + tool-result, keeping the rebuilt history valid.
-      parts.push({
-        type: `tool-${call.toolName}`,
-        toolCallId: call.toolCallId,
-        state: 'output-error',
-        input: call.input,
-        errorText: TOOL_CALL_INCOMPLETE_TEXT,
-      });
-    }
-  }
-  return parts;
-}
-
 export function assistantParts(
   steps: ReadonlyArray<StepLike> | undefined,
   fallbackText: string,
-  cache?: StepPartsCache,
 ): UIMessage['parts'] {
   const parts: Array<Record<string, unknown>> = [];
+  let sawText = false;
   for (const step of steps ?? []) {
-    // Memoize per step object (#490): a finished step is immutable and keeps its
-    // reference across flushes, so its parts (and the costly output stringify) are
-    // built exactly once per turn. A cache miss (or no cache) just rebuilds.
-    let stepParts = cache?.get(step as object);
-    if (!stepParts) {
-      stepParts = buildStepParts(step);
-      cache?.set(step as object, stepParts);
+    if (step.text) {
+      parts.push({ type: 'text', text: step.text });
+      sawText = true;
+    }
+    // Index this step's results by tool call id to pair calls with outputs.
+    const resultsById = new Map<string, unknown>();
+    for (const r of step.toolResults ?? []) {
+      if (r.toolCallId) resultsById.set(r.toolCallId, r.output);
+    }
+    // Index this step's THROWN tool failures (ai@6 `tool-error` content parts)
+    // by tool call id, so a call that failed replays with its real error text.
+    const errorsById = new Map<string, unknown>();
+    for (const part of step.content ?? []) {
+      if (part.type === 'tool-error' && part.toolCallId) {
+        errorsById.set(part.toolCallId, part.error);
+      }
+    }
+    for (const call of step.toolCalls ?? []) {
+      if (!call.toolName || !call.toolCallId) continue;
+      const hasResult = resultsById.has(call.toolCallId);
+      if (hasResult) {
+        // output-available: the tool returned; the next turn replays its result.
+        parts.push({
+          type: `tool-${call.toolName}`,
+          toolCallId: call.toolCallId,
+          state: 'output-available',
+          input: call.input,
+          output: compactToolOutput(resultsById.get(call.toolCallId)),
+        });
+      } else if (errorsById.has(call.toolCallId)) {
+        // The tool THREW: replay the REAL error so the model on the next turn
+        // knows WHY the call failed (and does not blindly repeat it). An
+        // output-error round-trips through convertToModelMessages as a balanced
+        // tool-call + tool-result, keeping the rebuilt history valid.
+        parts.push({
+          type: `tool-${call.toolName}`,
+          toolCallId: call.toolCallId,
+          state: 'output-error',
+          input: call.input,
+          errorText: normalizeToolError(errorsById.get(call.toolCallId)),
+        });
+      } else {
+        // No paired result AND no tool-error (e.g. aborted mid-step). Persisting
+        // a bare tool-call (input-available) would replay as an unpaired call and
+        // throw MissingToolResultsError on the next turn (convertToModelMessages
+        // emits no tool-result for it). Emit a SYNTHETIC paired result instead:
+        // an output-error round-trips through convertToModelMessages as a
+        // balanced tool-call + tool-result, keeping the rebuilt history valid.
+        parts.push({
+          type: `tool-${call.toolName}`,
+          toolCallId: call.toolCallId,
+          state: 'output-error',
+          input: call.input,
+          errorText: 'Tool call did not complete.',
+        });
+      }
     }
-    parts.push(...stepParts);
   }
-  const sawText = parts.some((p) => p.type === 'text');
   if (!sawText && fallbackText) {
     // No per-step text (e.g. a single final block): append the final text after
     // any tool parts so the natural call -> result -> answer order is preserved.
@@ -2872,16 +2586,6 @@ export function flushAssistant(
     maxContextTokens?: number;
     error?: string;
     pageChanged?: { title: string; diff: string } | null;
-    // Per-turn step->parts memo (#490): pass the SAME cache on every flush of a
-    // turn so each finished step's output is stringified once, not once per flush.
-    partsCache?: StepPartsCache;
-    // #490 observability: when the replay budgeter trimmed this turn's history,
-    // the (estimated) token size it trimmed to — the UI can show "replay truncated
-    // at N tokens". Omitted when nothing was trimmed.
-    replayTrimmedToTokens?: number;
-    // #490 reactive branch: set when the provider rejected this turn for context
-    // overflow. Stamped into metadata so the NEXT turn's budgeter trims aggressively.
-    replayOverflow?: boolean;
   },
 ): AssistantFlush {
   const finished = capturedSteps ?? [];
@@ -2891,32 +2595,13 @@ export function flushAssistant(
   // in-progress step's text (the partial answer cut off by an error/abort, or
   // simply not yet flushed mid-stream) as the last text part so the persisted
   // parts match what streamed to the client.
-  const parts = assistantParts(
-    finished,
-    '',
-    extra?.partsCache,
-  ) as unknown as Array<Record<string, unknown>>;
+  const parts = assistantParts(finished, '') as unknown as Array<
+    Record<string, unknown>
+  >;
   if (trailing) parts.push({ type: 'text', text: trailing });
 
   const metadata: Record<string, unknown> = {
     parts: parts as unknown as UIMessage['parts'],
-    // Era marker for the `tool_calls` trace shape (#490): v2 stores outcome flags
-    // ({ ok } / { error, kind }) and NO tool output (the output lives once in
-    // `parts`). Old rows have no marker and the legacy { output } shape; a
-    // dual-shape query branches on this. Old rows are deliberately NOT migrated.
-    toolTraceVersion: 2,
-    // #491 STEP MARKER: the number of FINISHED steps whose parts are in THIS row,
-    // written by the SAME flush that builds `parts` (atomically — they are both
-    // derived from `finished`, so the marker can NEVER disagree with the persisted
-    // parts). This is the step-alignment anchor the resume stack builds on:
-    // - the registry rotates its retention ring only on a CONFIRMED persist of
-    //   step N (commit 3);
-    // - attach slices the tail at "step > N" from the client's persisted seed.
-    // It is NOT `run.stepCount`: recordStep is fire-and-forget and NOT atomic with
-    // the parts write, so stepCount could race ahead of the persisted parts
-    // (seed↔marker drift). The in-progress trailing text (an error/abort partial,
-    // or a mid-stream flush) is NOT a finished step and is excluded from the count.
-    stepsPersisted: finished.length,
   };
   // finishReason: prefer an explicit one; else derive a sensible value from the
   // terminal status (so onError/onAbort records keep their historical reason).
@@ -2932,9 +2617,6 @@ export function flushAssistant(
   if (extra?.contextTokens) metadata.contextTokens = extra.contextTokens;
   if (extra?.maxContextTokens)
     metadata.maxContextTokens = extra.maxContextTokens;
-  if (extra?.replayTrimmedToTokens)
-    metadata.replayTrimmedToTokens = extra.replayTrimmedToTokens;
-  if (extra?.replayOverflow) metadata.replayOverflow = true;
   if (extra?.error) metadata.error = extra.error;
   // Persist the page-change diff the agent saw this turn (#274 observability),
   // so history / the Markdown export can show what the user changed. Only when
@@ -2960,85 +2642,42 @@ export function flushAssistant(
 
 /**
  * Reduce SDK step objects to a compact, JSON-serializable trace for the
- * `tool_calls` column — trace format **v2** (#490).
- *
- * v2 stores, per call, ONLY the metadata a queryable trace needs — never the
- * tool OUTPUT. Before #490 each output was persisted TWICE: once here (compacted)
- * and once in `metadata.parts` (via `assistantParts`), so a 50-step run with
- * 50–200 KB outputs wrote hundreds of MB per turn (each `onStepFinish` rewrote
- * the whole row). The parts copy is the one the model replays and the UI/Markdown
- * export render, so the trace copy of the output was pure duplication. v2 keeps
- * the output ONLY in parts and reduces the trace to outcome flags.
- *
- * Element shapes (paired per call, in order):
- *  - `{ toolName, input }`                       — the call
- *  - `{ toolName, ok: true }`                     — it returned a result (success)
- *  - `{ toolName, error, kind: 'thrown' }`        — it threw a `tool-error`
- *  - `{ toolName, error, kind: 'interrupted' }`   — no result and no throw (an
- *      abort / server restart mid-step). `kind` is MANDATORY: without it a
- *      synthetic "Tool call did not complete." is indistinguishable from a real
- *      hard-fail and pollutes any error-rate scan. The distinction is STRUCTURAL
- *      (an `errorsById` hit vs the synthetic fallback branch), NOT a per-tool
- *      classifier — soft failures stay OUT of the trace (they live in
- *      `metadata.parts` outputs; a per-tool mirror would persist its own bugs).
- *
- * Rows carry `metadata.toolTraceVersion: 2` (set by {@link flushAssistant}) so a
- * dual-shape query can branch on the era. Old rows are NOT migrated (rewriting
- * giant jsonb is the very WAL churn this removes); see docs/reading-ai-logs.md.
+ * `tool_calls` column. Stores only what the UI action-log and history need —
+ * never raw provider payloads or keys.
  */
 export function serializeSteps(
   steps: ReadonlyArray<{
-    toolCalls?: ReadonlyArray<{
-      toolCallId?: string;
-      toolName?: string;
-      input?: unknown;
-    }>;
-    toolResults?: ReadonlyArray<{ toolCallId?: string; toolName?: string }>;
+    toolCalls?: ReadonlyArray<{ toolName?: string; input?: unknown }>;
+    toolResults?: ReadonlyArray<{ toolName?: string; output?: unknown }>;
     content?: ReadonlyArray<{
       type?: string;
-      toolCallId?: string;
       toolName?: string;
       error?: unknown;
     }>;
   }>,
 ): unknown {
-  const calls: Array<
-    | { toolName?: string; input?: unknown }
-    | { toolName?: string; ok: true }
-    | { toolName?: string; error: string; kind: 'thrown' | 'interrupted' }
-  > = [];
+  const calls: Array<{
+    toolName?: string;
+    input?: unknown;
+    output?: unknown;
+    error?: string;
+  }> = [];
   for (const step of steps ?? []) {
-    // Index this step's results + thrown errors by tool call id, so each call is
-    // paired with its outcome (mirrors assistantParts' pairing exactly).
-    const resultIds = new Set<string>();
-    for (const r of step.toolResults ?? []) {
-      if (r.toolCallId) resultIds.add(r.toolCallId);
-    }
-    const errorsById = new Map<string, unknown>();
-    for (const part of step.content ?? []) {
-      if (part.type === 'tool-error' && part.toolCallId) {
-        errorsById.set(part.toolCallId, part.error);
-      }
-    }
     for (const call of step.toolCalls ?? []) {
       calls.push({ toolName: call.toolName, input: call.input });
-      if (call.toolCallId && resultIds.has(call.toolCallId)) {
-        // Success: the output itself lives in metadata.parts, not here.
-        calls.push({ toolName: call.toolName, ok: true });
-      } else if (call.toolCallId && errorsById.has(call.toolCallId)) {
-        // Hard fail: the tool threw. Persist the real (bounded) reason.
+    }
+    for (const r of step.toolResults ?? []) {
+      calls.push({ toolName: r.toolName, output: compactToolOutput(r.output) });
+    }
+    // ai@6 surfaces a THROWN tool failure as a `tool-error` content part, NOT as
+    // a `toolResults` entry. Record it as its own paired element (mirroring how a
+    // successful result is appended) so the failure and its reason survive in the
+    // trace instead of leaving an orphaned call with no result.
+    for (const part of step.content ?? []) {
+      if (part.type === 'tool-error') {
         calls.push({
-          toolName: call.toolName,
-          error: normalizeToolError(errorsById.get(call.toolCallId)),
-          kind: 'thrown',
-        });
-      } else {
-        // Neither a result nor a throw: interrupted mid-step (abort/restart).
-        // Marked structurally so it never inflates a thrown-error count.
-        calls.push({
-          toolName: call.toolName,
-          error: TOOL_CALL_INCOMPLETE_TEXT,
-          kind: 'interrupted',
+          toolName: part.toolName,
+          error: normalizeToolError(part.error),
         });
       }
     }

apps/server/src/core/ai-chat/ai-chat.step-marker.spec.ts

@@ -1,65 +0,0 @@
-import { flushAssistant } from './ai-chat.service';
-
-/**
- * #491 STEP MARKER — `metadata.stepsPersisted` is written by the SAME flush that
- * builds `metadata.parts`, so the marker can never disagree with the persisted
- * parts (the step-alignment anchor the resume stack builds on). These are
- * PROPERTY tests: they assert the marker tracks the number of FINISHED steps for
- * every flush shape.
- */
-
-// A finished step carrying one line of text and one tool call/result.
-function step(i: number) {
-  return {
-    text: `step ${i}`,
-    toolCalls: [
-      { toolCallId: `c${i}`, toolName: 'getPage', input: { id: `p${i}` } },
-    ],
-    toolResults: [
-      { toolCallId: `c${i}`, toolName: 'getPage', output: { title: `T${i}` } },
-    ],
-  };
-}
-
-describe('flushAssistant step marker (#491)', () => {
-  it('seed (no steps) → stepsPersisted 0', () => {
-    const f = flushAssistant([], '', 'streaming');
-    expect(f.metadata.stepsPersisted).toBe(0);
-  });
-
-  it('PROPERTY: stepsPersisted equals the number of FINISHED steps, for any N', () => {
-    for (let n = 0; n <= 6; n++) {
-      const steps = Array.from({ length: n }, (_, i) => step(i));
-      const f = flushAssistant(steps, '', 'streaming');
-      expect(f.metadata.stepsPersisted).toBe(n);
-      // ...and the parts actually contain those N steps' text (marker agrees with
-      // the persisted parts — the atomicity the whole design relies on).
-      const parts = f.metadata.parts as Array<Record<string, unknown>>;
-      const textParts = parts.filter((p) => p.type === 'text');
-      expect(textParts).toHaveLength(n);
-    }
-  });
-
-  it('an in-progress trailing partial does NOT increment the marker', () => {
-    // 2 finished steps + a partial (not-yet-finished) trailing text: the marker
-    // counts only the CONFIRMED step boundaries, not the partial.
-    const f = flushAssistant([step(0), step(1)], 'partial third step', 'error', {
-      error: 'boom',
-    });
-    expect(f.metadata.stepsPersisted).toBe(2);
-    // The partial text IS persisted in parts (so the user sees it), but it is not a
-    // counted step.
-    const parts = f.metadata.parts as Array<Record<string, unknown>>;
-    expect(parts[parts.length - 1]).toEqual({
-      type: 'text',
-      text: 'partial third step',
-    });
-  });
-
-  it('terminal completed flush counts all finished steps', () => {
-    const f = flushAssistant([step(0), step(1), step(2)], '', 'completed', {
-      finishReason: 'stop',
-    });
-    expect(f.metadata.stepsPersisted).toBe(3);
-  });
-});

apps/server/src/core/ai-chat/ai-chat.write-volume.int-spec.ts

@@ -1,209 +0,0 @@
-import { randomBytes } from 'crypto';
-import { Client } from 'pg';
-import { flushAssistant, serializeSteps } from './ai-chat.service';
-
-/**
- * #490 write-volume regression — an OBSERVABLE-PROPERTY test on a LIVE Postgres,
- * not "bytes through a mock repo" (a mock measures exactly the thing that does not
- * hurt). It drives a realistic 50-step run where each step returns a ~100 KB tool
- * output and, at every `onStepFinish`, UPDATEs the assistant row the way the
- * service does — then reads the REAL write volume via the `pg_current_wal_lsn()`
- * delta around the run.
- *
- * The property proven: v2 stores each tool OUTPUT only in `metadata.parts`, no
- * longer ALSO in the `tool_calls` trace. So:
- *   1. the trace (`tool_calls`) column's write volume is now O(Σ steps) — tiny,
- *      linear outcome flags — vs the pre-#490 O(N²) that re-persisted every prior
- *      output on every step; and
- *   2. the FULL-row write volume drops sharply (the duplicated output copy is gone).
- *
- * Connects to the local gitmost test Postgres (docker `gitmost-test-pg` on :5432);
- * SKIPS cleanly when that DB is not reachable so it never breaks a DB-less CI.
- */
-const CONN =
-  process.env.WAL_TEST_DATABASE_URL ??
-  'postgresql://docmost:docmost_dev_pw@localhost:5432/docmost';
-
-// A step whose tool output is ~100 KB (a page read), in the SDK StepLike shape.
-// The body is INCOMPRESSIBLE random text — a `'x'.repeat()` filler would TOAST-
-// compress to nothing and hide the real write volume (a page body does not).
-function makeStep(i: number, outputBytes = 100_000) {
-  const body = randomBytes(Math.ceil(outputBytes * 0.75)).toString('base64');
-  return {
-    text: `step ${i} reasoning`,
-    toolCalls: [{ toolCallId: `c${i}`, toolName: 'getPage', input: { id: `p${i}` } }],
-    toolResults: [
-      {
-        toolCallId: `c${i}`,
-        toolName: 'getPage',
-        output: { id: `p${i}`, title: `Page ${i}`, body },
-      },
-    ],
-  };
-}
-
-// The pre-#490 (v1) trace: outputs stored a SECOND time in `tool_calls`
-// (the duplication #490 removed). Mirrors the OLD serializeSteps shape.
-function v1Trace(steps: ReturnType<typeof makeStep>[]): unknown {
-  const calls: unknown[] = [];
-  for (const s of steps) {
-    for (const c of s.toolCalls) calls.push({ toolName: c.toolName, input: c.input });
-    for (const r of s.toolResults)
-      calls.push({ toolName: r.toolName, output: r.output });
-  }
-  return calls;
-}
-
-async function walDelta(
-  client: Client,
-  fn: () => Promise<void>,
-): Promise<number> {
-  const before = (await client.query('SELECT pg_current_wal_lsn() AS l')).rows[0]
-    .l as string;
-  await fn();
-  // NOTE: do NOT pg_switch_wal() here — a segment switch pads the LSN to the next
-  // 16 MB boundary and would swamp the actual write delta. The raw LSN advances by
-  // the bytes of WAL emitted, which is exactly what we want to measure.
-  const after = (await client.query('SELECT pg_current_wal_lsn() AS l')).rows[0]
-    .l as string;
-  return Number(
-    (await client.query('SELECT pg_wal_lsn_diff($1,$2) AS d', [after, before]))
-      .rows[0].d,
-  );
-}
-
-describe('#490 write-volume on a live Postgres (pg_current_wal_lsn delta)', () => {
-  let client: Client | undefined;
-  let available = false;
-
-  beforeAll(async () => {
-    try {
-      client = new Client(CONN);
-      await client.connect();
-      await client.query('SELECT pg_current_wal_lsn()');
-      available = true;
-    } catch {
-      available = false;
-      client = undefined;
-    }
-  });
-
-  afterAll(async () => {
-    await client?.end().catch(() => undefined);
-  });
-
-  const STEPS = 50;
-
-  it('v2 trace write volume is O(Σ steps) — a tiny fraction of the v1 duplicate', async () => {
-    if (!available || !client) {
-      console.warn('SKIP: gitmost-test-pg not reachable; skipping WAL test.');
-      return;
-    }
-    const c = client;
-    // Isolated table so we measure only the tool_calls (trace) column's writes.
-    await c.query('DROP TABLE IF EXISTS _wal_trace');
-    await c.query('CREATE TABLE _wal_trace(id int primary key, tool_calls jsonb)');
-    await c.query("INSERT INTO _wal_trace VALUES (1, '[]'::jsonb)");
-
-    const steps: ReturnType<typeof makeStep>[] = [];
-
-    // v1: each step re-persists ALL prior outputs into the trace (the O(N²) churn).
-    const v1 = await walDelta(c, async () => {
-      const acc: ReturnType<typeof makeStep>[] = [];
-      for (let i = 0; i < STEPS; i++) {
-        acc.push(makeStep(i));
-        await c.query('UPDATE _wal_trace SET tool_calls=$1 WHERE id=1', [
-          JSON.stringify(v1Trace(acc)),
-        ]);
-      }
-      steps.push(...acc);
-    });
-
-    await c.query("UPDATE _wal_trace SET tool_calls='[]'::jsonb WHERE id=1");
-
-    // v2: the REAL serializeSteps — outcome flags only, NO outputs.
-    const v2 = await walDelta(c, async () => {
-      const acc: ReturnType<typeof makeStep>[] = [];
-      for (let i = 0; i < STEPS; i++) {
-        acc.push(makeStep(i));
-        await c.query('UPDATE _wal_trace SET tool_calls=$1 WHERE id=1', [
-          JSON.stringify(serializeSteps(acc)),
-        ]);
-      }
-    });
-
-    await c.query('DROP TABLE IF EXISTS _wal_trace');
-
-    // eslint-disable-next-line no-console
-    console.log(
-      `[#490 WAL] trace column over ${STEPS} steps: v1=${(v1 / 1e6).toFixed(1)}MB ` +
-        `v2=${(v2 / 1e6).toFixed(2)}MB (${(v1 / v2).toFixed(0)}x smaller)`,
-    );
-
-    // The trace no longer carries outputs: v2 is a tiny fraction of v1's WAL.
-    expect(v2).toBeLessThan(v1 * 0.1);
-    // And v2's trace WAL is small in absolute terms — O(Σ steps) of flags, not
-    // O(N² × output). 50 steps of ~40-byte flags is well under a few MB of WAL.
-    expect(v2).toBeLessThan(5_000_000);
-    // v1's duplicate alone is huge (≈ the 100 KB output re-written N² times).
-    expect(v1).toBeGreaterThan(50_000_000);
-  }, 120_000);
-
-  it('the full assistant row write drops sharply once the duplicate is gone', async () => {
-    if (!available || !client) return;
-    const c = client;
-    await c.query('DROP TABLE IF EXISTS _wal_full');
-    await c.query(
-      'CREATE TABLE _wal_full(id int primary key, content text, tool_calls jsonb, metadata jsonb, status text)',
-    );
-    await c.query("INSERT INTO _wal_full VALUES (1, '', '[]'::jsonb, '{}'::jsonb, 'streaming')");
-
-    const writeRow = async (patch: {
-      content: string;
-      toolCalls: unknown;
-      metadata: unknown;
-      status: string;
-    }) =>
-      c.query(
-        'UPDATE _wal_full SET content=$1, tool_calls=$2, metadata=$3, status=$4 WHERE id=1',
-        [
-          patch.content,
-          JSON.stringify(patch.toolCalls ?? null),
-          JSON.stringify(patch.metadata),
-          patch.status,
-        ],
-      );
-
-    // v2 (real flushAssistant): outputs live once, in metadata.parts.
-    const v2 = await walDelta(c, async () => {
-      const acc: ReturnType<typeof makeStep>[] = [];
-      for (let i = 0; i < STEPS; i++) {
-        acc.push(makeStep(i));
-        await writeRow(flushAssistant(acc as never, '', 'streaming'));
-      }
-    });
-
-    await c.query("UPDATE _wal_full SET content='', tool_calls='[]'::jsonb, metadata='{}'::jsonb WHERE id=1");
-
-    // v1: same row PLUS the duplicated outputs in the trace column.
-    const v1 = await walDelta(c, async () => {
-      const acc: ReturnType<typeof makeStep>[] = [];
-      for (let i = 0; i < STEPS; i++) {
-        acc.push(makeStep(i));
-        const f = flushAssistant(acc as never, '', 'streaming');
-        await writeRow({ ...f, toolCalls: v1Trace(acc) });
-      }
-    });
-
-    await c.query('DROP TABLE IF EXISTS _wal_full');
-
-    // eslint-disable-next-line no-console
-    console.log(
-      `[#490 WAL] full row over ${STEPS} steps: v1=${(v1 / 1e6).toFixed(1)}MB ` +
-        `v2=${(v2 / 1e6).toFixed(1)}MB (saved ${((1 - v2 / v1) * 100).toFixed(0)}%)`,
-    );
-
-    // Removing the duplicated trace copy is a large, real write-volume reduction.
-    expect(v2).toBeLessThan(v1 * 0.75);
-  }, 120_000);
-});

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

@@ -1,10 +1,4 @@
-import {
-  IsISO8601,
-  IsOptional,
-  IsString,
-  MaxLength,
-  MinLength,
-} from 'class-validator';
+import { IsOptional, IsString, MaxLength, MinLength } from 'class-validator';
 
 /** Identify a chat by id (workspace-scoped on the server). */
 export class ChatIdDto {
@@ -43,24 +37,6 @@ export class GetChatMessagesDto {
   cursor?: string;
 }
 
-/**
- * Delta poll (#491): pull the chat's rows changed since `cursor` (a DB-clock
- * timestamp from the previous poll) plus the current run fact — the degraded-poll
- * fallback's payload, replacing the full infinite-query refetch. Omit `cursor` on
- * the first poll (returns just a fresh cursor to start the chain).
- */
-export class GetChatDeltaDto {
-  @IsString()
-  chatId: string;
-
-  // ISO-8601 timestamp echoed from the previous poll's response. Validated as
-  // ISO-8601 (not a bare string): a malformed cursor would otherwise reach the
-  // `::timestamptz` cast in findByChatUpdatedAfter and 500 instead of a clean 400.
-  @IsOptional()
-  @IsISO8601()
-  cursor?: string;
-}
-
 /** Resolve the chat bound to a document (the page's most-recent owned chat). */
 export class BoundChatDto {
   @IsString()

apps/server/src/core/ai-chat/history-budget.spec.ts

@@ -1,266 +0,0 @@
-import type { ModelMessage } from 'ai';
-import {
-  resolveReplayBudget,
-  isContextOverflowError,
-  estimateMessagesTokens,
-  trimHistoryForReplay,
-  REPLAY_BUDGET_DEFAULT_TOKENS,
-  REPLAY_TRUNCATION_MARKER,
-  REPLAY_TURN_COLLAPSED_MARKER,
-} from './history-budget';
-
-describe('resolveReplayBudget', () => {
-  it('uses floor(0.7 x window) for a configured window (no cap)', () => {
-    // 0.7 x 60k = 42k
-    expect(resolveReplayBudget(60_000)).toEqual({
-      thresholdTokens: 42_000,
-      usedDefault: false,
-    });
-    // 0.7 x 1M = 700k — NOT capped (anti-brick vs the window, not a cost limiter).
-    expect(resolveReplayBudget(1_000_000)).toEqual({
-      thresholdTokens: 700_000,
-      usedDefault: false,
-    });
-  });
-
-  it('accepts the raw ::text stored form', () => {
-    expect(resolveReplayBudget('60000').thresholdTokens).toBe(42_000);
-  });
-
-  // The crux (#490): a chat with NO context window configured must STILL be
-  // budgeted — those are exactly the installs that hit terminal overflow.
-  it('applies the flat default when the window is unset/empty', () => {
-    expect(resolveReplayBudget(undefined)).toEqual({
-      thresholdTokens: REPLAY_BUDGET_DEFAULT_TOKENS,
-      usedDefault: true,
-    });
-    expect(resolveReplayBudget('')).toEqual({
-      thresholdTokens: REPLAY_BUDGET_DEFAULT_TOKENS,
-      usedDefault: true,
-    });
-    expect(resolveReplayBudget('   ')).toEqual({
-      thresholdTokens: REPLAY_BUDGET_DEFAULT_TOKENS,
-      usedDefault: true,
-    });
-  });
-
-  it('treats an explicit 0 as the off-switch (distinct from unset)', () => {
-    expect(resolveReplayBudget(0)).toEqual({
-      thresholdTokens: null,
-      usedDefault: false,
-    });
-    expect(resolveReplayBudget('0')).toEqual({
-      thresholdTokens: null,
-      usedDefault: false,
-    });
-  });
-
-  it('falls back to the default on a negative/garbage value', () => {
-    expect(resolveReplayBudget(-5).usedDefault).toBe(true);
-    expect(resolveReplayBudget('abc').usedDefault).toBe(true);
-  });
-});
-
-describe('isContextOverflowError', () => {
-  it('classifies a real provider 400 context-overflow shape', () => {
-    // OpenAI-compatible shape.
-    expect(
-      isContextOverflowError({
-        statusCode: 400,
-        message:
-          "This model's maximum context length is 128000 tokens. However, your messages resulted in 214000 tokens. Please reduce the length of the messages.",
-      }),
-    ).toBe(true);
-    // Anthropic-style wording.
-    expect(
-      isContextOverflowError({
-        status: 400,
-        message: 'prompt is too long: 250000 tokens > 200000 maximum',
-      }),
-    ).toBe(true);
-    // Nested body + string status.
-    expect(
-      isContextOverflowError({
-        response: { status: '400' },
-        message: 'input is too long for the requested model',
-      }),
-    ).toBe(true);
-    // Error instance with the cause carrying the body.
-    const e = new Error('Bad request');
-    (e as any).statusCode = 400;
-    (e as any).cause = new Error('maximum context window exceeded');
-    expect(isContextOverflowError(e)).toBe(true);
-  });
-
-  it('does NOT classify unrelated 400s or auth/rate-limit errors', () => {
-    expect(
-      isContextOverflowError({ statusCode: 400, message: 'invalid tool schema' }),
-    ).toBe(false);
-    expect(
-      isContextOverflowError({
-        statusCode: 429,
-        message: 'context length exceeded but rate limited',
-      }),
-    ).toBe(false);
-    expect(isContextOverflowError({ statusCode: 500, message: 'server error' })).toBe(
-      false,
-    );
-    expect(isContextOverflowError(undefined)).toBe(false);
-    expect(isContextOverflowError('some random string')).toBe(false);
-  });
-});
-
-// Helpers to build ModelMessage fixtures in the ai@6 shape.
-const userMsg = (text: string): ModelMessage =>
-  ({ role: 'user', content: [{ type: 'text', text }] }) as ModelMessage;
-const assistantMsg = (
-  text: string,
-  toolCallId?: string,
-  toolName?: string,
-): ModelMessage =>
-  ({
-    role: 'assistant',
-    content: [
-      { type: 'text', text },
-      ...(toolCallId
-        ? [{ type: 'tool-call', toolCallId, toolName, input: {} }]
-        : []),
-    ],
-  }) as ModelMessage;
-const toolMsg = (
-  toolCallId: string,
-  toolName: string,
-  value: unknown,
-): ModelMessage =>
-  ({
-    role: 'tool',
-    content: [
-      { type: 'tool-result', toolCallId, toolName, output: { type: 'json', value } },
-    ],
-  }) as ModelMessage;
-
-describe('trimHistoryForReplay', () => {
-  it('null budget disables trimming (returns the same reference)', () => {
-    const msgs = [userMsg('hi'), assistantMsg('yo')];
-    const r = trimHistoryForReplay(msgs, null);
-    expect(r.trimmed).toBe(false);
-    expect(r.messages).toBe(msgs);
-  });
-
-  it('leaves history under budget untouched (same reference)', () => {
-    const msgs = [userMsg('hi'), assistantMsg('a short answer')];
-    const r = trimHistoryForReplay(msgs, 100_000);
-    expect(r.trimmed).toBe(false);
-    expect(r.messages).toBe(msgs);
-  });
-
-  it('truncates OLD tool outputs but keeps recent turns full', () => {
-    const big = 'X'.repeat(40_000); // ~16k tokens on its own
-    const msgs: ModelMessage[] = [];
-    // 6 OLD turns (indices 0..5), each with a huge tool output.
-    for (let i = 0; i < 6; i++) {
-      msgs.push(userMsg(`old q${i}`));
-      msgs.push(assistantMsg('looking', `c${i}`, 'getPage'));
-      msgs.push(toolMsg(`c${i}`, 'getPage', { body: big }));
-      msgs.push(assistantMsg(`old a${i}`));
-    }
-    // 3 small recent turns, then the CURRENT turn with its own huge tool output.
-    // With REPLAY_KEEP_RECENT_TURNS=4 the last 4 user-turns stay full, so only
-    // these small recent turns + the current big one are kept full; the 6 old
-    // turns above fall in the trim region.
-    for (let i = 0; i < 3; i++) {
-      msgs.push(userMsg(`recent q${i}`));
-      msgs.push(assistantMsg(`recent a${i}`));
-    }
-    msgs.push(userMsg('current q'));
-    msgs.push(assistantMsg('looking', 'cR', 'getPage'));
-    msgs.push(toolMsg('cR', 'getPage', { body: big }));
-    msgs.push(assistantMsg('current a'));
-
-    // Budget large enough that phase-1 tool truncation alone brings it under.
-    const r = trimHistoryForReplay(msgs, 30_000);
-    expect(r.trimmed).toBe(true);
-    const flat = JSON.stringify(r.messages);
-    // The CURRENT turn's tool output survives in full.
-    expect(flat).toContain(big);
-    // Old outputs were truncated with the marker.
-    expect(flat).toContain(REPLAY_TRUNCATION_MARKER);
-    // Phase 1 sufficed: the oldest turns were NOT collapsed.
-    expect(flat).not.toContain(REPLAY_TURN_COLLAPSED_MARKER);
-    expect(estimateMessagesTokens(r.messages)).toBeLessThan(
-      estimateMessagesTokens(msgs),
-    );
-  });
-
-  it('collapses the oldest turns when tool truncation is not enough', () => {
-    // Many turns with LARGE assistant TEXT (not tool output) so phase 1 can't help.
-    const bigText = 'слово '.repeat(8_000); // large Cyrillic text per turn
-    const msgs: ModelMessage[] = [];
-    for (let i = 0; i < 12; i++) {
-      msgs.push(userMsg(`q${i}`));
-      msgs.push(assistantMsg(bigText));
-    }
-    const r = trimHistoryForReplay(msgs, 30_000);
-    expect(r.trimmed).toBe(true);
-    // Oldest turns collapsed; result fits (best-effort) and is much smaller.
-    expect(estimateMessagesTokens(r.messages)).toBeLessThan(
-      estimateMessagesTokens(msgs),
-    );
-    // The LAST turn's text is preserved in full (recent turns stay full).
-    expect(JSON.stringify(r.messages[r.messages.length - 1])).toContain(bigText);
-  });
-
-  it('is deterministic / byte-stable for identical inputs', () => {
-    const big = 'Y'.repeat(30_000);
-    const build = (): ModelMessage[] => {
-      const m: ModelMessage[] = [];
-      for (let i = 0; i < 10; i++) {
-        m.push(userMsg(`q${i}`));
-        m.push(assistantMsg('t', `c${i}`, 'getPage'));
-        m.push(toolMsg(`c${i}`, 'getPage', { body: big }));
-      }
-      return m;
-    };
-    const a = trimHistoryForReplay(build(), 15_000);
-    const b = trimHistoryForReplay(build(), 15_000);
-    expect(JSON.stringify(a.messages)).toBe(JSON.stringify(b.messages));
-  });
-
-  it('never leaves an unpaired tool-call after collapsing (balanced history)', () => {
-    const big = 'Z'.repeat(40_000);
-    const msgs: ModelMessage[] = [];
-    for (let i = 0; i < 10; i++) {
-      msgs.push(userMsg(`q${i}`));
-      msgs.push(assistantMsg('t', `c${i}`, 'getPage'));
-      msgs.push(toolMsg(`c${i}`, 'getPage', { body: big }));
-    }
-    const r = trimHistoryForReplay(msgs, 8_000);
-    // Count tool-call vs tool-result parts in the trimmed output.
-    let calls = 0;
-    let results = 0;
-    for (const m of r.messages) {
-      if (!Array.isArray(m.content)) continue;
-      for (const p of m.content as Array<{ type?: string }>) {
-        if (p.type === 'tool-call') calls++;
-        if (p.type === 'tool-result' || p.type === 'tool-error') results++;
-      }
-    }
-    // Every surviving tool-call has a surviving result (collapsing drops BOTH).
-    expect(calls).toBe(results);
-    // Collapsed turns carry the marker.
-    expect(JSON.stringify(r.messages)).toContain(REPLAY_TURN_COLLAPSED_MARKER);
-  });
-
-  it('respects the provider fact: under-budget contextTokens skips trimming', () => {
-    const big = 'W'.repeat(60_000);
-    const msgs = [
-      userMsg('q'),
-      assistantMsg('t', 'c1', 'getPage'),
-      toolMsg('c1', 'getPage', { body: big }),
-    ];
-    // char-estimate is high, but the provider says we are well under budget.
-    const r = trimHistoryForReplay(msgs, 100_000, 5_000);
-    expect(r.trimmed).toBe(false);
-    expect(r.messages).toBe(msgs);
-  });
-});

apps/server/src/core/ai-chat/history-budget.ts

@@ -1,375 +0,0 @@
-/**
- * History-replay token budget (#490).
- *
- * The whole persisted conversation is replayed to the provider on EVERY turn, so
- * a long chat eventually exceeds the model's context window and the provider 400s
- * on every turn — terminally (the chat "bricks"). This module bounds the replayed
- * history at REPLAY TIME only: it never mutates what is persisted (the DB stays
- * the full record), and its output is a deterministic, byte-stable function of its
- * input so the trimmed prefix is identical turn to turn (provider prompt-cache
- * friendliness — real money on long chats).
- *
- * The PRIMARY signal is the provider's own fact: `metadata.contextTokens` from the
- * last turn. The chars-based {@link estimateTokens} (shared with the client) is
- * used only for the DELTA of not-yet-sent messages, to decide WHAT to trim, and as
- * the fallback for chats with no usage yet.
- */
-import type { ModelMessage } from 'ai';
-import { estimateTokens } from '@docmost/token-estimate';
-
-/** Flat default budget when no context window is configured (tokens). */
-export const REPLAY_BUDGET_DEFAULT_TOKENS = 100_000;
-/** Fraction of a configured context window used as the budget. */
-export const REPLAY_BUDGET_WINDOW_FRACTION = 0.7;
-/**
- * Fraction of the normal budget used for the REACTIVE re-trim after a provider
- * context-overflow 400 — the preventive estimate under-counted, so cut harder.
- */
-export const REPLAY_AGGRESSIVE_FRACTION = 0.5;
-/**
- * Turns (a user message + its assistant/tool replies) kept FULL at the tail,
- * including the current one — never trimmed. Older turns are compacted first.
- */
-export const REPLAY_KEEP_RECENT_TURNS = 4;
-/** Leading chars kept from a truncated old tool output. */
-export const REPLAY_TOOL_OUTPUT_HEAD = 800;
-/** Trailing chars kept from a truncated old tool output. */
-export const REPLAY_TOOL_OUTPUT_TAIL = 300;
-/** Marker inserted where an old tool output was truncated for replay. */
-export const REPLAY_TRUNCATION_MARKER =
-  '[…truncated for replay; call the tool again to read the full output]';
-/** Marker for a whole old turn collapsed to its text. */
-export const REPLAY_TURN_COLLAPSED_MARKER =
-  '[earlier tool activity omitted for replay]';
-
-export interface ReplayBudget {
-  /** Token threshold above which replay history is trimmed; `null` = OFF. */
-  thresholdTokens: number | null;
-  /** True when the flat default was used (no context window configured). */
-  usedDefault: boolean;
-}
-
-/**
- * Resolve the replay budget from the RAW stored `chatContextWindow` (text/number).
- *  - a positive value  -> `floor(fraction × window)` (NO cap — the budgeter is
- *    anti-brick protection against the window itself, not a cost/economy limiter,
- *    exactly as the codebase already treats maxOutputTokens; the reactive branch
- *    still guarantees anti-brick regardless of how high this budget is)
- *  - explicit `0`       -> OFF (admin opt-out; `null` threshold)
- *  - unset/empty/invalid-> the flat default (still protects — the installations
- *    that hit terminal overflow are exactly the ones that never set a window)
- *
- * Note the raw value is needed because the parsed `chatContextWindow` collapses
- * both `0` and unset to `undefined`, which would erase the explicit off-switch.
- */
-export function resolveReplayBudget(rawContextWindow: unknown): ReplayBudget {
-  let n: number | undefined;
-  if (typeof rawContextWindow === 'number') {
-    n = rawContextWindow;
-  } else if (typeof rawContextWindow === 'string') {
-    const t = rawContextWindow.trim();
-    n = t === '' ? undefined : Number(t);
-  }
-  // Unset / empty / non-numeric / negative -> flat default (the protective case).
-  if (n === undefined || !Number.isFinite(n) || n < 0) {
-    return { thresholdTokens: REPLAY_BUDGET_DEFAULT_TOKENS, usedDefault: true };
-  }
-  // Explicit 0 -> off-switch.
-  if (n === 0) {
-    return { thresholdTokens: null, usedDefault: false };
-  }
-  return {
-    thresholdTokens: Math.floor(REPLAY_BUDGET_WINDOW_FRACTION * n),
-    usedDefault: false,
-  };
-}
-
-/**
- * The effective replay threshold for THIS turn, given the base budget and whether
- * the PREVIOUS turn hit a context-overflow 400 (the reactive-recovery signal,
- * `metadata.replayOverflow`). On recovery the base budget is scaled down by
- * {@link REPLAY_AGGRESSIVE_FRACTION}: the overflowing turn produced no usage
- * signal, so the preventive estimate under-counted and a normal-threshold trim may
- * not shrink enough to fit — this harder cut is what un-bricks the chat.
- *
- * A `null` base budget (trimming OFF) is passed through unchanged: an explicit
- * off-switch is never overridden by the recovery path.
- */
-export function resolveEffectiveReplayThreshold(
-  thresholdTokens: number | null,
-  priorOverflowed: boolean,
-): number | null {
-  if (!priorOverflowed || thresholdTokens == null) return thresholdTokens;
-  return Math.floor(thresholdTokens * REPLAY_AGGRESSIVE_FRACTION);
-}
-
-/**
- * True when a provider error is a CONTEXT-OVERFLOW rejection (the prompt exceeds
- * the model's window). Providers surface this as an HTTP 400 with a recognizable
- * message; match both the status and the message patterns robustly across
- * OpenAI-compatible / Anthropic / Gemini wordings, since the exact shape varies.
- */
-export function isContextOverflowError(error: unknown): boolean {
-  const status = extractStatus(error);
-  const msg = extractMessage(error).toLowerCase();
-  // Message patterns seen across providers for "prompt too long".
-  const overflowPattern =
-    /context (?:length|window)|maximum context|too many tokens|too large for|reduce the length|prompt is too long|input (?:is )?too long|exceeds? the (?:maximum )?(?:context|token)|maximum.*tokens|string too long/;
-  if (!overflowPattern.test(msg)) return false;
-  // A 400/413 with an overflow-shaped message is an overflow. Some providers
-  // omit/rewrite the status, so accept the message match when the status is
-  // unknown, but reject it for auth/rate-limit statuses that never mean overflow.
-  if (status === 400 || status === 413) return true;
-  if (status === 401 || status === 403 || status === 429) return false;
-  return true;
-}
-
-function extractStatus(error: unknown): number | undefined {
-  if (!error || typeof error !== 'object') return undefined;
-  const e = error as Record<string, unknown>;
-  for (const k of ['statusCode', 'status']) {
-    const v = e[k];
-    if (typeof v === 'number') return v;
-    if (typeof v === 'string' && /^\d+$/.test(v)) return Number(v);
-  }
-  // Nested (e.g. { response: { status } } / { cause: { statusCode } }).
-  for (const k of ['response', 'cause', 'data']) {
-    const nested = e[k];
-    if (nested && typeof nested === 'object') {
-      const s = extractStatus(nested);
-      if (s !== undefined) return s;
-    }
-  }
-  return undefined;
-}
-
-function extractMessage(error: unknown): string {
-  if (error == null) return '';
-  if (typeof error === 'string') return error;
-  if (error instanceof Error) {
-    // Include nested causes (provider libs wrap the real body in `cause`).
-    const cause = (error as { cause?: unknown }).cause;
-    return `${error.message} ${cause ? extractMessage(cause) : ''}`;
-  }
-  if (typeof error === 'object') {
-    const e = error as Record<string, unknown>;
-    const parts: string[] = [];
-    for (const k of ['message', 'error', 'body', 'responseBody', 'data']) {
-      const v = e[k];
-      if (typeof v === 'string') parts.push(v);
-      else if (v && typeof v === 'object') parts.push(extractMessage(v));
-    }
-    return parts.join(' ');
-  }
-  return String(error);
-}
-
-/** Rough token size of a ModelMessage array via the shared chars estimator. */
-export function estimateMessagesTokens(
-  messages: ReadonlyArray<ModelMessage>,
-): number {
-  let total = 0;
-  for (const m of messages) {
-    total += estimateTokens(serializeContent(m.content));
-  }
-  return total;
-}
-
-function serializeContent(content: unknown): string {
-  if (typeof content === 'string') return content;
-  try {
-    return JSON.stringify(content) ?? '';
-  } catch {
-    return '';
-  }
-}
-
-/** Deep JSON string of an arbitrary value, bounded so estimation never throws. */
-function stringifyValue(value: unknown): string {
-  if (typeof value === 'string') return value;
-  try {
-    return JSON.stringify(value) ?? String(value);
-  } catch {
-    return String(value);
-  }
-}
-
-export interface TrimResult {
-  messages: ModelMessage[];
-  /** Whether any trimming was applied. */
-  trimmed: boolean;
-  /** Estimated tokens of the returned messages (chars-based). */
-  estimatedTokens: number;
-}
-
-/**
- * Bound the replayed history to `budgetTokens`, deterministically. Returns the
- * SAME array reference (no copy) when nothing needs trimming, so the common case
- * is free and byte-identical. Trimming order (spec #490):
- *   1. truncate OLD turns' tool outputs (head+tail + marker) — the bulk of the size
- *   2. mechanically collapse the OLDEST turns to their text (concatenation, no LLM)
- *   3. the current + last {@link REPLAY_KEEP_RECENT_TURNS} turns stay FULL
- *
- * `budgetTokens === null` disables trimming. `priorContextTokens` (the provider's
- * fact from last turn) short-circuits the decision: when it is known and already
- * under budget we skip trimming even if the char-estimate is higher (the provider
- * count is authoritative). The char-estimate drives WHAT to cut.
- */
-export function trimHistoryForReplay(
-  messages: ModelMessage[],
-  budgetTokens: number | null,
-  priorContextTokens?: number,
-): TrimResult {
-  if (budgetTokens == null) {
-    return { messages, trimmed: false, estimatedTokens: 0 };
-  }
-  const estimated = estimateMessagesTokens(messages);
-  // Decision signal: prefer the provider's fact (last turn's contextTokens) plus
-  // the estimated delta of the messages appended since; fall back to the pure
-  // char-estimate for a chat with no usage yet.
-  const projected =
-    priorContextTokens != null
-      ? Math.max(priorContextTokens, estimated)
-      : estimated;
-  if (projected <= budgetTokens) {
-    return { messages, trimmed: false, estimatedTokens: estimated };
-  }
-
-  // The tail we always keep full: from the Nth-from-last user message onward.
-  const boundary = recentBoundaryIndex(messages, REPLAY_KEEP_RECENT_TURNS);
-  const tail = messages.slice(boundary);
-  let head = messages.slice(0, boundary).map(cloneMessage);
-
-  // Phase 1: truncate old tool outputs.
-  for (const m of head) {
-    if (m.role === 'tool') truncateToolMessage(m);
-  }
-  let out = [...head, ...tail];
-  let est = estimateMessagesTokens(out);
-  if (est <= budgetTokens) {
-    return { messages: out, trimmed: true, estimatedTokens: est };
-  }
-
-  // Phase 2: collapse the oldest turns (in `head`) to their text, one at a time,
-  // from the oldest, until we fit or the whole head is collapsed.
-  const turns = splitTurns(head);
-  const collapsed: ModelMessage[] = [];
-  let i = 0;
-  for (; i < turns.length; i++) {
-    if (est <= budgetTokens) break;
-    collapsed.push(...collapseTurn(turns[i]));
-    // Re-estimate the whole prospective output.
-    const remaining = turns.slice(i + 1).flat();
-    out = [...collapsed, ...remaining, ...tail];
-    est = estimateMessagesTokens(out);
-  }
-  // Include any turns we didn't need to collapse.
-  const remaining = turns.slice(i).flat();
-  out = [...collapsed, ...remaining, ...tail];
-  est = estimateMessagesTokens(out);
-  return { messages: out, trimmed: true, estimatedTokens: est };
-}
-
-/** Index of the first message of the Nth-from-last user turn (0 if fewer). */
-function recentBoundaryIndex(
-  messages: ReadonlyArray<ModelMessage>,
-  keepTurns: number,
-): number {
-  const userIdx: number[] = [];
-  for (let i = 0; i < messages.length; i++) {
-    if (messages[i].role === 'user') userIdx.push(i);
-  }
-  if (userIdx.length <= keepTurns) return 0;
-  return userIdx[userIdx.length - keepTurns];
-}
-
-/** Split a message list into turns; each turn starts at a `user` message. */
-function splitTurns(messages: ModelMessage[]): ModelMessage[][] {
-  const turns: ModelMessage[][] = [];
-  for (const m of messages) {
-    if (m.role === 'user' || turns.length === 0) turns.push([m]);
-    else turns[turns.length - 1].push(m);
-  }
-  return turns;
-}
-
-/**
- * Collapse a whole turn to its plain text (mechanical concatenation, not an LLM
- * summary). Keeps the user message; replaces the assistant/tool messages with a
- * single assistant text message = the assistant's concatenated text + a marker
- * when tool activity was dropped. Dropping BOTH the tool-call and tool-result
- * parts together keeps the rebuilt history balanced (no unpaired calls).
- */
-function collapseTurn(turn: ModelMessage[]): ModelMessage[] {
-  const out: ModelMessage[] = [];
-  let assistantText = '';
-  let hadTools = false;
-  for (const m of turn) {
-    if (m.role === 'user') {
-      out.push(m);
-    } else if (m.role === 'assistant') {
-      const { text, tools } = extractAssistantText(m.content);
-      assistantText += text;
-      hadTools = hadTools || tools;
-    } else if (m.role === 'tool') {
-      hadTools = true;
-    } else {
-      out.push(m);
-    }
-  }
-  const note =
-    (assistantText ? assistantText.trimEnd() : '') +
-    (hadTools
-      ? `${assistantText ? '\n\n' : ''}${REPLAY_TURN_COLLAPSED_MARKER}`
-      : '');
-  if (note) out.push({ role: 'assistant', content: note } as ModelMessage);
-  return out;
-}
-
-function extractAssistantText(content: unknown): {
-  text: string;
-  tools: boolean;
-} {
-  if (typeof content === 'string') return { text: content, tools: false };
-  if (!Array.isArray(content)) return { text: '', tools: false };
-  let text = '';
-  let tools = false;
-  for (const part of content) {
-    const type = (part as { type?: string })?.type;
-    if (type === 'text') text += (part as { text?: string }).text ?? '';
-    else if (type === 'tool-call') tools = true;
-  }
-  return { text, tools };
-}
-
-/** Truncate every tool-result output in a `tool` message to head+tail+marker. */
-function truncateToolMessage(message: ModelMessage): void {
-  const content = message.content;
-  if (!Array.isArray(content)) return;
-  for (const part of content) {
-    const p = part as { type?: string; output?: { type?: string; value?: unknown } };
-    if (p.type !== 'tool-result' && p.type !== 'tool-error') continue;
-    if (!p.output) continue;
-    const raw = stringifyValue(p.output.value);
-    const budget = REPLAY_TOOL_OUTPUT_HEAD + REPLAY_TOOL_OUTPUT_TAIL;
-    if (raw.length <= budget + REPLAY_TRUNCATION_MARKER.length) continue;
-    const truncated =
-      raw.slice(0, REPLAY_TOOL_OUTPUT_HEAD) +
-      `\n${REPLAY_TRUNCATION_MARKER}\n` +
-      raw.slice(raw.length - REPLAY_TOOL_OUTPUT_TAIL);
-    // Represent the shrunk output as a text output (a valid tool-result output).
-    p.output = { type: 'text', value: truncated };
-  }
-}
-
-/** Shallow-ish clone so trimming never mutates the caller's (persisted-derived)
- *  message objects — only the OLD region is cloned before it is edited. */
-function cloneMessage(m: ModelMessage): ModelMessage {
-  if (typeof m.content === 'string') return { ...m };
-  return {
-    ...m,
-    content: (m.content as unknown[]).map((p) =>
-      p && typeof p === 'object' ? { ...(p as object) } : p,
-    ),
-  } as ModelMessage;
-}

apps/server/src/database/migrations/20260707T120000-ai-chat-metadata.ts

@@ -1,24 +0,0 @@
-import { type Kysely, sql } from 'kysely';
-
-export async function up(db: Kysely<any>): Promise<void> {
-  // Chat-level metadata bag (#490). First use: the deferred-tool ACTIVATION set
-  // (`activatedTools`) is persisted here so it survives across turns — previously
-  // the set was reset every turn, forcing the model to re-run loadTools and pay a
-  // fresh round-trip to re-activate the same tools each turn. On load the stored
-  // set is intersected with the current valid deferred names, so an allowlist /
-  // role change can never inject a now-nonexistent tool.
-  //
-  // jsonb, defaulted to '{}' so every row (incl. pre-migration ones, backfilled
-  // by the default) is a readable object — the app never has to null-guard the
-  // bag itself, only individual keys.
-  await db.schema
-    .alterTable('ai_chats')
-    .addColumn('metadata', 'jsonb', (col) =>
-      col.notNull().defaultTo(sql`'{}'::jsonb`),
-    )
-    .execute();
-}
-
-export async function down(db: Kysely<any>): Promise<void> {
-  await db.schema.alterTable('ai_chats').dropColumn('metadata').execute();
-}

apps/server/src/database/migrations/20260707T120000-page-history-kind.ts

@@ -0,0 +1,27 @@
+import { type Kysely } from 'kysely';
+
+/**
+ * #370 — page-versioning intentionality tier on a history snapshot.
+ *
+ * Adds `page_history.kind`, the three-tier "how intentional was this snapshot"
+ * marker that lets versions (intentional points) be told apart from autosaves:
+ *   - 'manual'   — a human explicitly saved a version (Cmd+S / Save button)
+ *   - 'agent'    — the AI agent explicitly saved a version
+ *   - 'idle'     — trailing idle-flush autosnapshot (safety net)
+ *   - 'boundary' — autosnapshot pinned on a source transition (user↔agent↔git)
+ *
+ * Nullable with NO default (mirrors last_updated_source in the agent-provenance
+ * migration): legacy rows predate the marker and read back as `null`, which the
+ * client renders as a plain autosave. Stored as a short varchar to stay
+ * forward-compatible without an enum migration.
+ */
+export async function up(db: Kysely<any>): Promise<void> {
+  await db.schema
+    .alterTable('page_history')
+    .addColumn('kind', 'varchar(20)', (col) => col)
+    .execute();
+}
+
+export async function down(db: Kysely<any>): Promise<void> {
+  await db.schema.alterTable('page_history').dropColumn('kind').execute();
+}

apps/server/src/database/repos/ai-chat/ai-chat-message.repo.delta.int-spec.ts

@@ -1,280 +0,0 @@
-import { randomUUID } from 'crypto';
-import { CamelCasePlugin, Kysely, sql } from 'kysely';
-import { PostgresJSDialect } from 'kysely-postgres-js';
-// NOT a default import: the project tsconfig is `module: commonjs` with NO
-// esModuleInterop, so `import postgres from 'postgres'` compiles to
-// `postgres_1.default(...)` and the CJS `postgres` export has no `.default` —
-// it threw in beforeAll, was swallowed as "DB unreachable", and SILENTLY voided
-// all six tests. Mirror the working integration harness (test/integration/db.ts).
-import * as postgres from 'postgres';
-import { AiChatMessageRepo } from './ai-chat-message.repo';
-import { AiChatRunRepo } from './ai-chat-run.repo';
-
-/**
- * #491 delta-poll — OBSERVABLE-PROPERTY tests against a LIVE Postgres (the local
- * gitmost test DB, docker `gitmost-test-pg` on :5432), not "rows through a mock"
- * (a mock cannot observe the DB clock nor the overlap-window race — the very
- * things that matter here). Drives the REAL repo methods (`findByChatUpdatedAfter`,
- * the now()-stamped `update`) and asserts:
- *   1. delta-relevant writes stamp `updatedAt` from the DB clock, not the app clock
- *      (proven by faking the process clock far into the future and observing the
- *      stamp stays on real DB time);
- *   2. the poll returns only rows changed after the cursor, ordered, with a fresh
- *      DB-clock cursor;
- *   3. the "committed late but stamped earlier than the cursor" RACE is caught by
- *      the overlap window (a naive `updatedAt > cursor` would MISS it);
- *   4. the overlap GUARANTEES repeats across close polls — the contract behind the
- *      client's idempotent merge (mergeById).
- *
- * INTEGRATION lane (`*.int-spec.ts`): runs under `test:int`, whose global-setup
- * DROPS + RE-CREATES + MIGRATES `docmost_test`, so the real `ai_chat_messages` /
- * `ai_chat_runs` tables EXIST here. (It was previously a `.spec.ts` defaulting to
- * the UNmigrated dev `docmost`; in the CI unit lane — where `WAL_TEST_DATABASE_URL`
- * is unset and only `test:int` migrates — that meant 5/6 ERROR
- * `relation "ai_chat_messages" does not exist`, silently voiding coverage of the
- * risky cursor/overlap logic. Renaming to `.int-spec.ts` + defaulting the DSN to
- * `docmost_test` fixes the CI fidelity.)
- *
- * FK triggers are bypassed (`session_replication_role = replica`) so synthetic
- * chat/workspace ids need no parent fixtures; a single pooled connection (max 1)
- * keeps that session setting for every query. SKIPS cleanly when the DB is
- * unreachable so a DB-less CI never breaks.
- */
-const CONN =
-  process.env.WAL_TEST_DATABASE_URL ??
-  process.env.TEST_DATABASE_URL ??
-  'postgresql://docmost:docmost_dev_pw@localhost:5432/docmost_test';
-
-let db: Kysely<any>;
-let sqlClient: ReturnType<typeof postgres>;
-let msgRepo: AiChatMessageRepo;
-let runRepo: AiChatRunRepo;
-let reachable = false;
-
-const workspaceId = randomUUID();
-const chatId = randomUUID();
-
-beforeAll(async () => {
-  try {
-    sqlClient = postgres(CONN, { max: 1, onnotice: () => {} });
-    db = new Kysely<any>({
-      dialect: new PostgresJSDialect({ postgres: sqlClient }),
-      plugins: [new CamelCasePlugin()],
-    });
-    // Single connection keeps this session-scoped bypass for the whole suite.
-    await sql`set session_replication_role = replica`.execute(db);
-    await sql`select 1`.execute(db);
-    reachable = true;
-  } catch (err) {
-    reachable = false;
-    // A genuine connection failure (ECONNREFUSED etc.) is a legitimate skip on a
-    // DB-less CI. A PROGRAMMING error (bad import, typo, driver misuse) must NOT
-    // masquerade as "DB unreachable" and silently void the whole suite (that is
-    // exactly the bug that hid this spec's zero coverage) — rethrow it so the
-    // suite fails LOUDLY.
-    const msg = String((err as Error)?.message ?? err);
-    if (
-      !/ECONNREFUSED|ENOTFOUND|ETIMEDOUT|EHOSTUNREACH|connect|terminating|password|authentication|role .* does not exist|database .* does not exist/i.test(
-        msg,
-      )
-    ) {
-      throw err;
-    }
-  }
-  msgRepo = new AiChatMessageRepo(db as never);
-  runRepo = new AiChatRunRepo(db as never);
-});
-
-afterAll(async () => {
-  if (db) {
-    try {
-      await db
-        .deleteFrom('aiChatMessages')
-        .where('workspaceId', '=', workspaceId)
-        .execute();
-      await db
-        .deleteFrom('aiChatRuns')
-        .where('workspaceId', '=', workspaceId)
-        .execute();
-    } catch {
-      /* best-effort cleanup */
-    }
-    await db.destroy();
-  }
-});
-
-afterEach(() => {
-  jest.useRealTimers();
-});
-
-async function seedMessage(overrides: Record<string, unknown> = {}) {
-  return msgRepo.insert({
-    chatId,
-    workspaceId,
-    userId: null as never,
-    role: 'assistant',
-    content: 'x',
-    status: 'streaming',
-    ...overrides,
-  } as never);
-}
-
-async function dbNow(): Promise<string> {
-  const r = await sql<{ now: Date }>`select now() as now`.execute(db);
-  return r.rows[0].now.toISOString();
-}
-
-// Fake ONLY the Date object (so in-process `new Date()`/`Date.now()` jump), while
-// leaving every TIMER function real. Faking timers wholesale freezes postgres.js's
-// internal connection/query timers, so the awaited DB round-trip would hang the
-// test (and the afterAll cleanup) at the jest 5s cap. With Date-only faking the
-// query resolves normally, and we still prove the stamp is the DB clock (not the
-// skewed process clock).
-function fakeDateOnly(iso: string): void {
-  jest.useFakeTimers({
-    doNotFake: [
-      'hrtime',
-      'nextTick',
-      'performance',
-      'queueMicrotask',
-      'requestAnimationFrame',
-      'cancelAnimationFrame',
-      'requestIdleCallback',
-      'cancelIdleCallback',
-      'setImmediate',
-      'clearImmediate',
-      'setInterval',
-      'clearInterval',
-      'setTimeout',
-      'clearTimeout',
-    ],
-    now: new Date(iso),
-  });
-}
-
-const maybe = (name: string, fn: () => Promise<void>) =>
-  it(name, async () => {
-    if (!reachable) {
-      console.warn(`SKIP (${name}): test DB unreachable at ${CONN}`);
-      return;
-    }
-    await fn();
-  });
-
-describe('AiChatMessageRepo.findByChatUpdatedAfter (#491 delta poll)', () => {
-  maybe('null cursor returns no rows and a fresh DB-clock cursor', async () => {
-    const before = await dbNow();
-    const { rows, cursor } = await msgRepo.findByChatUpdatedAfter(
-      chatId,
-      workspaceId,
-      null,
-    );
-    expect(rows).toEqual([]);
-    expect(new Date(cursor).getTime()).toBeGreaterThanOrEqual(
-      new Date(before).getTime(),
-    );
-  });
-
-  maybe('returns only rows changed after the cursor', async () => {
-    const { cursor: c0 } = await msgRepo.findByChatUpdatedAfter(
-      chatId,
-      workspaceId,
-      null,
-    );
-    const m = await seedMessage();
-    const { rows, cursor: c1 } = await msgRepo.findByChatUpdatedAfter(
-      chatId,
-      workspaceId,
-      c0,
-    );
-    expect(rows.map((r) => r.id)).toContain(m.id);
-    // Cursor is monotonic (advances).
-    expect(new Date(c1).getTime()).toBeGreaterThanOrEqual(
-      new Date(c0).getTime(),
-    );
-  });
-
-  maybe(
-    'RACE: a row stamped BEFORE the cursor but seen after is caught by the overlap',
-    async () => {
-      // Cursor taken now; then a row appears whose updatedAt is 2s in the PAST
-      // (committed late on another connection but stamped earlier). A naive
-      // `updatedAt > cursor` would MISS it; the 5s overlap window catches it.
-      const cursor = await dbNow();
-      const m = await seedMessage();
-      await sql`update ai_chat_messages set updated_at = now() - interval '2 seconds' where id = ${m.id}`.execute(
-        db,
-      );
-      const { rows } = await msgRepo.findByChatUpdatedAfter(
-        chatId,
-        workspaceId,
-        cursor,
-      );
-      expect(rows.map((r) => r.id)).toContain(m.id);
-    },
-  );
-
-  maybe(
-    'overlap GUARANTEES repeats across close polls (idempotent-merge contract)',
-    async () => {
-      const { cursor: c0 } = await msgRepo.findByChatUpdatedAfter(
-        chatId,
-        workspaceId,
-        null,
-      );
-      const m = await seedMessage();
-      const first = await msgRepo.findByChatUpdatedAfter(
-        chatId,
-        workspaceId,
-        c0,
-      );
-      expect(first.rows.map((r) => r.id)).toContain(m.id);
-      // Immediately re-poll with the JUST-returned cursor: the row is still within
-      // the overlap window, so it is returned AGAIN — the client MUST dedupe by id.
-      const second = await msgRepo.findByChatUpdatedAfter(
-        chatId,
-        workspaceId,
-        first.cursor,
-      );
-      expect(second.rows.map((r) => r.id)).toContain(m.id);
-    },
-  );
-
-  maybe(
-    'update() stamps updatedAt from the DB clock, not the app clock',
-    async () => {
-      const m = await seedMessage();
-      // Skew the PROCESS clock ~73 years into the future (Date only). If the stamp
-      // came from `new Date()` the row would read year 2099; sql now() keeps it on
-      // DB time.
-      fakeDateOnly('2099-01-01T00:00:00Z');
-      const updated = await msgRepo.update(m.id, workspaceId, {
-        content: 'y',
-      });
-      jest.useRealTimers();
-      expect(updated).toBeDefined();
-      expect(new Date(updated!.updatedAt).getFullYear()).toBeLessThan(2099);
-    },
-  );
-
-  maybe(
-    'run update() also stamps updatedAt from the DB clock',
-    async () => {
-      const run = await runRepo.insert({
-        chatId,
-        workspaceId,
-        createdBy: null as never,
-        trigger: 'user',
-        status: 'running',
-        stepCount: 0,
-      } as never);
-      fakeDateOnly('2099-01-01T00:00:00Z');
-      const updated = await runRepo.update(run.id, workspaceId, {
-        stepCount: 1,
-      });
-      jest.useRealTimers();
-      expect(updated).toBeDefined();
-      expect(new Date(updated!.updatedAt).getFullYear()).toBeLessThan(2099);
-    },
-  );
-});

apps/server/src/database/repos/ai-chat/ai-chat-message.repo.ts

@@ -25,20 +25,6 @@ const SWEEP_STREAMING_STALE_MS = 10 * 60 * 1000; // 10 minutes
 // into memory; far above any realistic transcript length.
 const FIND_ALL_BY_CHAT_LIMIT = 5000;
 
-// Delta-poll overlap (#491): the poll query reaches this far BEHIND the client's
-// echoed cursor, so a row that committed with an `updatedAt` marginally before the
-// previous cursor was taken (on another autocommit connection) is still caught.
-// Sized well above realistic single-row commit skew; the client merge is
-// idempotent by id (mergeById), so the guaranteed repeats the overlap produces are
-// harmless.
-export const DELTA_POLL_OVERLAP_SECONDS = 5;
-
-// Hard cap on rows one delta poll returns — a safety bound (a poll should carry a
-// handful of just-changed rows, never a whole transcript). Ordered by (updatedAt,
-// id) asc, so on the pathological overflow the OLDEST changes win and the newest
-// are picked up by the next poll (its cursor did not advance past them).
-export const DELTA_POLL_MAX_ROWS = 500;
-
 @Injectable()
 export class AiChatMessageRepo {
   private readonly logger = new Logger(AiChatMessageRepo.name);
@@ -153,72 +139,6 @@ export class AiChatMessageRepo {
       .executeTakeFirst();
   }
 
-  /**
-   * Delta read (#491) for the degraded poll: the chat's messages whose row
-   * changed AFTER the client's `cursor`, plus a FRESH cursor taken from the DB
-   * clock. Replaces the old "refetch ALL infinite-query pages every 2.5s with
-   * full parts" poll — the client seeds once (findByChat) and thereafter pulls
-   * only the deltas and merges them by id (mergeById).
-   *
-   * Cursor: a DB-clock timestamp (now()) the client echoes back each poll. All
-   * delta-relevant writes stamp `updatedAt` with now() (see `update` /
-   * `finalizeOwner`), so this is a SINGLE monotonic axis. The query overlaps the
-   * cursor by DELTA_POLL_OVERLAP_SECONDS to catch a row committed with an
-   * `updatedAt` marginally BEFORE the previous cursor was taken on another
-   * connection (single-row autocommit UPDATEs; no long transactions). The overlap
-   * GUARANTEES occasional REPEATS, so the client merge MUST be idempotent by id.
-   *
-   * `cursor === null` (first poll after the full seed) returns NO rows — there is
-   * nothing "new" relative to a just-loaded seed — only the fresh cursor to start
-   * the delta chain. The fresh cursor is read AFTER the rows, so it is >= every
-   * returned row's `updatedAt` (they were read strictly earlier) — a row that
-   * commits between the rows-read and the cursor-read is at most
-   * DELTA_POLL_OVERLAP_SECONDS behind the returned cursor, so the next poll's
-   * overlap window always re-includes it (no miss).
-   */
-  async findByChatUpdatedAfter(
-    chatId: string,
-    workspaceId: string,
-    cursor: string | null,
-  ): Promise<{ rows: AiChatMessage[]; cursor: string }> {
-    if (cursor === null) {
-      const nowRow = await sql<{ now: Date }>`select now() as now`.execute(
-        this.db,
-      );
-      return { rows: [], cursor: nowRow.rows[0].now.toISOString() };
-    }
-    // Overlap the client cursor by DELTA_POLL_OVERLAP_SECONDS, computed in SQL off
-    // the echoed cursor so the whole comparison stays on the DB clock.
-    const rows = await this.db
-      .selectFrom('aiChatMessages')
-      .select(this.baseFields)
-      .where('chatId', '=', chatId)
-      .where('workspaceId', '=', workspaceId)
-      .where('deletedAt', 'is', null)
-      .where(
-        'updatedAt',
-        '>',
-        sql<Date>`${cursor}::timestamptz - make_interval(secs => ${DELTA_POLL_OVERLAP_SECONDS})`,
-      )
-      .orderBy('updatedAt', 'asc')
-      .orderBy('id', 'asc')
-      .limit(DELTA_POLL_MAX_ROWS)
-      .execute();
-    // When the page filled (pathological overflow), DO NOT advance the cursor to
-    // now(): that would skip the changed rows past the cap that this poll did not
-    // return. Resume from the last returned row's updatedAt instead (the next
-    // poll's overlap re-includes ties by id). In the normal case the fresh DB-clock
-    // now() is the cursor.
-    if (rows.length === DELTA_POLL_MAX_ROWS) {
-      return {
-        rows,
-        cursor: rows[rows.length - 1].updatedAt.toISOString(),
-      };
-    }
-    const nowRow = await sql<{ now: Date }>`select now() as now`.execute(this.db);
-    return { rows, cursor: nowRow.rows[0].now.toISOString() };
-  }
-
   async insert(
     insertable: InsertableAiChatMessage,
     trx?: KyselyTransaction,
@@ -252,13 +172,7 @@ export class AiChatMessageRepo {
     const db = dbOrTx(this.db, opts?.trx);
     let query = db
       .updateTable('aiChatMessages')
-      // #491: stamp `updatedAt` from the DB clock (sql now()), NOT the app clock
-      // (new Date()). The delta-poll cursor (findByChatUpdatedAfter) is a single
-      // DB-clock axis; a per-step 'streaming' UPDATE stamped with the app clock
-      // would be a SECOND, skewed clock source and could leave a row's updatedAt
-      // just under a cursor taken from now() on another connection — an
-      // independent source of delta MISSES. All delta-relevant writes use now().
-      .set({ ...(patch as Record<string, unknown>), updatedAt: sql`now()` })
+      .set({ ...(patch as Record<string, unknown>), updatedAt: new Date() })
       .where('id', '=', id)
       .where('workspaceId', '=', workspaceId);
     // Concurrency guard (#183 review): a per-step 'streaming' update must NEVER
@@ -300,9 +214,7 @@ export class AiChatMessageRepo {
     const db = dbOrTx(this.db, trx);
     return db
       .updateTable('aiChatMessages')
-      // #491: DB-clock stamp (see `update`) — this terminal write flips the row's
-      // status, which the delta poll must observe on the shared now() cursor axis.
-      .set({ ...(patch as Record<string, unknown>), updatedAt: sql`now()` })
+      .set({ ...(patch as Record<string, unknown>), updatedAt: new Date() })
       .where('id', '=', id)
       .where('workspaceId', '=', workspaceId)
       .where((eb) =>
@@ -337,9 +249,7 @@ export class AiChatMessageRepo {
       .set({
         status,
         metadata: sql`coalesce(metadata, '{}'::jsonb) || jsonb_build_object('finalizeFailed', true)`,
-        // #491: DB-clock stamp (see `update`) so a reconcile status flip lands on
-        // the same now() cursor axis the delta poll reads.
-        updatedAt: sql`now()`,
+        updatedAt: new Date(),
       })
       .where('id', '=', id)
       .where('workspaceId', '=', workspaceId)
@@ -397,9 +307,7 @@ export class AiChatMessageRepo {
       .set({
         status: 'aborted',
         metadata: sql`coalesce(m.metadata, '{}'::jsonb) || jsonb_build_object('finalizeFailed', true)`,
-        // #491: DB-clock stamp (see `update`). The staleness WHERE below stays on
-        // the app clock — a >minutes window makes the ms-scale skew irrelevant.
-        updatedAt: sql`now()`,
+        updatedAt: new Date(),
       })
       .where('m.status', '=', 'streaming')
       .where('m.updatedAt', '<', staleBefore)
@@ -443,8 +351,7 @@ export class AiChatMessageRepo {
       .set({
         status: 'aborted',
         metadata: sql`coalesce(metadata, '{}'::jsonb) || jsonb_build_object('finalizeFailed', true)`,
-        // #491: DB-clock stamp (see `update`). Staleness WHERE stays app-clock.
-        updatedAt: sql`now()`,
+        updatedAt: new Date(),
       })
       .where('status', '=', 'streaming')
       .where('updatedAt', '<', staleBefore)

apps/server/src/database/repos/ai-chat/ai-chat-run.repo.spec.ts

@@ -62,17 +62,10 @@ describe('AiChatRunRepo.sweepRunning', () => {
     // ...but a fresh 'running' run (updatedAt = now) must NOT be skipped: no
     // updatedAt predicate at all on the boot path.
     expect(rec.wheres.some(([col]) => col === 'updatedAt')).toBe(false);
-    // It flips to 'aborted' and stamps finishedAt + updatedAt. #491: the stamps
-    // are now DB-clock `sql now()` expressions (raw builders), NOT app-clock
-    // `new Date()`, so the run row shares the delta poll's single now() cursor axis
-    // — assert they are present and are the sql raw-builder objects (not a Date,
-    // not undefined).
-    expect(rec.set?.status).toBe('aborted');
-    for (const stamp of ['finishedAt', 'updatedAt'] as const) {
-      expect(rec.set?.[stamp]).toBeDefined();
-      expect(rec.set?.[stamp]).not.toBeInstanceOf(Date);
-      expect(typeof rec.set?.[stamp]).toBe('object');
-    }
+    // It flips to 'aborted' and stamps finishedAt.
+    expect(rec.set).toEqual(
+      expect.objectContaining({ status: 'aborted', finishedAt: expect.any(Date) }),
+    );
   });
 
   it('phase-2 path: an explicit staleMs reintroduces the updatedAt window', async () => {

apps/server/src/database/repos/ai-chat/ai-chat-run.repo.ts

@@ -136,11 +136,7 @@ export class AiChatRunRepo {
     const db = dbOrTx(this.db, trx);
     return db
       .updateTable('aiChatRuns')
-      // #491: DB-clock stamp (sql now()) so the run row shares the delta poll's
-      // single now() cursor axis with the assistant message rows — a run-status
-      // change (the run fact the delta carries) must never sit on a skewed app
-      // clock relative to the message updatedAt cursor.
-      .set({ ...(patch as Record<string, unknown>), updatedAt: sql`now()` })
+      .set({ ...(patch as Record<string, unknown>), updatedAt: new Date() })
       .where('id', '=', id)
       .where('workspaceId', '=', workspaceId)
       .returning(this.baseFields)
@@ -166,15 +162,14 @@ export class AiChatRunRepo {
     trx?: KyselyTransaction,
   ): Promise<AiChatRun | undefined> {
     const db = dbOrTx(this.db, trx);
+    const now = new Date();
     return db
       .updateTable('aiChatRuns')
       .set({
         status: patch.status,
         error: patch.error,
-        // #491: DB-clock stamps (finished_at + updated_at) so the terminal run
-        // fact lands on the delta poll's now() cursor axis.
-        finishedAt: sql`now()`,
-        updatedAt: sql`now()`,
+        finishedAt: now,
+        updatedAt: now,
       })
       .where('id', '=', id)
       .where('workspaceId', '=', workspaceId)
@@ -197,8 +192,7 @@ export class AiChatRunRepo {
     const db = dbOrTx(this.db, trx);
     return db
       .updateTable('aiChatRuns')
-      // #491: DB-clock stamps (see `update`).
-      .set({ stopRequestedAt: sql`now()`, updatedAt: sql`now()` })
+      .set({ stopRequestedAt: new Date(), updatedAt: new Date() })
       .where('id', '=', id)
       .where('workspaceId', '=', workspaceId)
       .where('status', 'in', ACTIVE_RUN_STATUSES as unknown as string[])
@@ -255,14 +249,13 @@ export class AiChatRunRepo {
     trx?: KyselyTransaction,
   ): Promise<number> {
     const db = dbOrTx(this.db, trx);
+    const now = new Date();
     let query = db
       .updateTable('aiChatRuns')
       .set({
         status: 'aborted',
-        // #491: DB-clock stamps (see `update`). The staleness WHERE below stays on
-        // the app clock — a >minutes window makes the ms-scale skew irrelevant.
-        finishedAt: sql`now()`,
-        updatedAt: sql`now()`,
+        finishedAt: now,
+        updatedAt: now,
         error: sql`coalesce(error, ${'Run interrupted by a server restart.'})`,
       })
       .where('status', 'in', ACTIVE_RUN_STATUSES as unknown as string[]);
@@ -270,7 +263,7 @@ export class AiChatRunRepo {
     // sibling replica's live run is never aborted. Omitted on the phase-1 boot
     // sweep -> unconditional.
     if (typeof opts.staleMs === 'number') {
-      const staleBefore = new Date(Date.now() - opts.staleMs);
+      const staleBefore = new Date(now.getTime() - opts.staleMs);
       query = query.where('updatedAt', '<', staleBefore);
     }
     const rows = await query.returning('id').execute();

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

@@ -13,6 +13,7 @@ import { jsonArrayFrom, jsonObjectFrom } from 'kysely/helpers/postgres';
 import { ExpressionBuilder, sql } from 'kysely';
 import { DB } from '@docmost/db/types/db';
 import { resolveAgentProvenance } from '../agent-provenance';
+import { PageHistoryKind } from '../../../collaboration/constants';
 
 /**
  * Role-resolution subquery for a page-history row's bound AI chat (#300). Joins
@@ -46,6 +47,9 @@ export class PageHistoryRepo {
     'lastUpdatedById',
     'lastUpdatedSource',
     'lastUpdatedAiChatId',
+    // #370 — intentionality tier ('manual' | 'agent' | 'idle' | 'boundary');
+    // null on legacy rows (= autosave). Selected so callers can read/promote it.
+    'kind',
     'contributorIds',
     'spaceId',
     'workspaceId',
@@ -85,9 +89,15 @@ export class PageHistoryRepo {
 
   async saveHistory(
     page: Page,
-    opts?: { contributorIds?: string[]; trx?: KyselyTransaction },
-  ): Promise<void> {
-    await this.insertPageHistory(
+    opts?: {
+      contributorIds?: string[];
+      // #370 — intentionality tier for this snapshot. Omitted → null (legacy
+      // autosave semantics). Callers derive it server-side, never from a client.
+      kind?: PageHistoryKind;
+      trx?: KyselyTransaction;
+    },
+  ): Promise<PageHistory> {
+    return await this.insertPageHistory(
       {
         pageId: page.id,
         slugId: page.slugId,
@@ -99,6 +109,7 @@ export class PageHistoryRepo {
         // Copy the provenance marker off the page row, as for lastUpdatedById.
         lastUpdatedSource: page.lastUpdatedSource,
         lastUpdatedAiChatId: page.lastUpdatedAiChatId,
+        kind: opts?.kind ?? null,
         contributorIds: opts?.contributorIds,
         spaceId: page.spaceId,
         workspaceId: page.workspaceId,
@@ -107,6 +118,25 @@ export class PageHistoryRepo {
     );
   }
 
+  /**
+   * #370 — promote an existing snapshot's intentionality tier in place. Used by
+   * the manual-save "promote-not-dup" path: when the latest history row already
+   * holds the exact content being versioned, we upgrade its `kind` instead of
+   * duplicating a heavy content row.
+   */
+  async updateHistoryKind(
+    pageHistoryId: string,
+    kind: PageHistoryKind,
+    trx?: KyselyTransaction,
+  ): Promise<void> {
+    const db = dbOrTx(this.db, trx);
+    await db
+      .updateTable('pageHistory')
+      .set({ kind })
+      .where('id', '=', pageHistoryId)
+      .execute();
+  }
+
   async findPageHistoryByPageId(pageId: string, pagination: PaginationOptions) {
     const query = this.db
       .selectFrom('pageHistory')

apps/server/src/database/types/db.d.ts

@@ -280,6 +280,7 @@ export interface PageHistory {
   createdAt: Generated<Timestamp>;
   icon: string | null;
   id: Generated<string>;
+  kind: string | null;
   lastUpdatedAiChatId: string | null;
   lastUpdatedById: string | null;
   lastUpdatedSource: string | null;
@@ -606,9 +607,6 @@ export interface AiChats {
   // The document the chat was created in (open page at first message). NULL =>
   // started outside any document. ON DELETE SET NULL on the page FK.
   pageId: string | null;
-  // Chat-level metadata bag (#490). jsonb, defaulted to '{}'. First key:
-  // `activatedTools` — the deferred-tool activation set persisted across turns.
-  metadata: Generated<Json>;
   createdAt: Generated<Timestamp>;
   updatedAt: Generated<Timestamp>;
   deletedAt: Timestamp | null;

apps/server/src/integrations/ai/ai-settings.service.ts

@@ -245,9 +245,6 @@ export class AiSettingsService {
       // Max context window for the chat header badge denominator. Stored as
       // ::text; 0/unset/invalid = no limit (undefined).
       chatContextWindow: parsePositiveInt(provider.chatContextWindow),
-      // RAW stored value (#490): the replay budgeter reads this to distinguish an
-      // explicit `0` (off-switch) from unset, which parsePositiveInt cannot.
-      chatContextWindowRaw: provider.chatContextWindow,
       // Plain passthrough; getChatModel defaults unset to 'openai-compatible'.
       chatApiStyle: provider.chatApiStyle,
       // Cheap model id for the anonymous public-share assistant; reuses the chat

apps/server/src/integrations/ai/ai.types.ts

@@ -105,10 +105,6 @@ export interface ResolvedAiConfig extends Partial<AiProviderSettings> {
   // Max context window in tokens; surfaced to the chat header badge as the
   // "current / max" denominator. 0/unset = no limit.
   chatContextWindow?: number;
-  // RAW stored context window (::text), BEFORE parsePositiveInt collapses `0` and
-  // unset to `undefined`. The #490 replay budgeter needs the raw value to honor an
-  // explicit `0` off-switch distinctly from "unset -> flat default".
-  chatContextWindowRaw?: string | number;
   // Cheap model id for the public-share assistant; reuses the chat creds.
   publicShareChatModel?: string;
   // Agent-role id whose persona the public-share assistant adopts (empty/unset

apps/server/src/integrations/queue/constants/queue.interface.ts

@@ -20,6 +20,10 @@ export interface IStripeSeatsSyncJob {
 
 export interface IPageHistoryJob {
   pageId: string;
+  // #370 — intentionality tier the worker stamps on the snapshot. All jobs on
+  // this queue are trailing idle-flush autosnapshots, so this is 'idle' (absent
+  // → treated as 'idle' by the processor).
+  kind?: 'idle';
 }
 
 /**

apps/server/test/integration/ai-chat-attach.int-spec.ts

@@ -30,13 +30,11 @@ import {
  * tees the SSE frames into it via `consumeSseStream` while stamping the DB row id
  * via `generateMessageId` (both gated on runId + the resumable flag).
  *
- * Proven here (tail-only #491): a finished run attached at its persisted frontier
- * N_final delivers only the TAIL past N (a synthetic `start` carrying the run-fact
- * + the terminal `finish`/`[DONE]`) — the step content below N lives in the seeded
- * DB row, NOT the ring; the anchor check (invariant 6); an attach opened BEFORE the
- * first frame follows the live stream from frame 0; an explicit stop surfaces
- * `{"type":"abort"}` + `[DONE]` + end to the subscriber; and the legacy (non-run)
- * path tees nothing.
+ * Proven here: a finished run's replay is the full frame sequence incl `[DONE]`
+ * with `start.messageId` == the seeded DB row id; the anchor check (invariant 6);
+ * an attach opened BEFORE the first frame follows the live stream from frame 0; an
+ * explicit stop surfaces `{"type":"abort"}` + `[DONE]` + end to the subscriber;
+ * and the legacy (non-run) path tees nothing.
  */
 
 const sleep = (ms: number) => new Promise((r) => setTimeout(r, ms));
@@ -135,16 +133,14 @@ function liveSink(): {
   };
 }
 
-// Parse the first `start` frame's JSON out of a `data: {...}` sequence.
-function parseStartFrame(
-  frames: string[],
-): { messageId?: string; messageMetadata?: any } | undefined {
+// The SSE `start` frame carries the message id; pull it out of a `data: {...}`.
+function parseStartMessageId(frames: string[]): string | undefined {
   for (const f of frames) {
     const m = /^data: (\{.*\})\s*$/m.exec(f.trim());
     if (!m) continue;
     try {
       const json = JSON.parse(m[1]);
-      if (json.type === 'start') return json;
+      if (json.type === 'start') return json.messageId;
     } catch {
       /* not this frame */
     }
@@ -274,7 +270,7 @@ describe('AiChatService run-stream attach [integration]', () => {
     await destroyTestDb();
   });
 
-  it('run-wrapped, tail-only: a finished run at N_final delivers the run-fact start + finish/[DONE]; the step content lives in the seeded row', async () => {
+  it('run-wrapped: replay is the full frame sequence incl [DONE], start.messageId == the seeded DB row id', async () => {
     const chatId = (await createChat(db, { workspaceId, creatorId: userId })).id;
     const registry = new AiChatStreamRegistryService();
     const runService = new AiChatRunService(runRepo, {
@@ -304,37 +300,27 @@ describe('AiChatService run-stream attach [integration]', () => {
         );
       });
       const rowId = await assistantRowId(chatId);
-      // The client reads its persisted step frontier N from the seeded row.
-      const row: any = await msgRepo.findById(rowId, workspaceId);
-      const nFinal = row.metadata.stepsPersisted as number;
-      expect(nFinal).toBe(1); // a single finished step
-      // The step content is in the SEEDED row (parts/content), not the ring.
-      expect(JSON.stringify(row.metadata.parts)).toContain('Hello');
 
-      // Attach at N_final with the correct anchor: the tail past step 1 is just
-      // the terminal frames; step 0's 'Hello' is BELOW the frontier (seeded).
+      // Finished-run replay with expect=live + the correct anchor.
       const sink = liveSink();
-      const att = await registry.attach(chatId, rowId, nFinal, sink.cb);
+      const att = await registry.attach(chatId, true, rowId, sink.cb);
       expect(att).not.toBeNull();
       expect(att!.finished).toBe(true);
-      // The synthetic start frame carries the run-fact (runId/chatId), the source
-      // of the run-fact on re-attach.
-      const start = parseStartFrame(att!.replay);
-      expect(start?.messageMetadata).toMatchObject({
-        runId: box.runId,
-        chatId,
-      });
-      // The terminal marker is delivered so the client's SDK closes the stream.
+      // The tee captured frames (consumeSseStream was wired).
+      expect(att!.replay.length).toBeGreaterThan(0);
+      // generateMessageId stamped the DB row id onto the streamed start frame.
+      expect(parseStartMessageId(att!.replay)).toBe(rowId);
+      // The full sequence includes the streamed text and the terminal marker.
+      const joined = att!.replay.join('');
+      expect(joined).toContain('Hello');
       expect(att!.replay.some((f) => f.includes('[DONE]'))).toBe(true);
-      // 'Hello' (step 0, below the frontier) is NOT re-streamed — it is seeded.
-      expect(att!.replay.some((f) => f.includes('Hello'))).toBe(false);
     } finally {
       registry.onModuleDestroy();
       await cleanup();
     }
   });
 
-  it('anchor mismatch returns null (invariant 6)', async () => {
+  it('anchor mismatch with expect=live returns null (invariant 6)', async () => {
     const chatId = (await createChat(db, { workspaceId, creatorId: userId })).id;
     const registry = new AiChatStreamRegistryService();
     const runService = new AiChatRunService(runRepo, {
@@ -361,7 +347,7 @@ describe('AiChatService run-stream attach [integration]', () => {
       const sink = liveSink();
       // A foreign anchor must NOT replay this run's transcript.
       expect(
-        await registry.attach(chatId, 'a-different-run-row', 1, sink.cb),
+        await registry.attach(chatId, true, 'a-different-run-row', sink.cb),
       ).toBeNull();
     } finally {
       registry.onModuleDestroy();
@@ -390,11 +376,8 @@ describe('AiChatService run-stream attach [integration]', () => {
     try {
       // Attach while the entry exists (opened at begin) but before any frame.
       const sink = liveSink();
-      const att = (await registry.attach(chatId, undefined, 0, sink.cb))!;
-      // Nothing streamed yet -> the tail is just the synthetic start frame; the
-      // whole live stream (start..DONE) follows via onFrame after start().
-      expect(att.replay).toHaveLength(1);
-      expect(att.replay[0]).toContain('"type":"start"');
+      const att = (await registry.attach(chatId, false, undefined, sink.cb))!;
+      expect(att.replay).toEqual([]); // nothing streamed yet -> replay from 0
       att.start(); // go live (drains nothing, then follows)
 
       // Now emit the whole turn.
@@ -465,7 +448,7 @@ describe('AiChatService run-stream attach [integration]', () => {
     });
     try {
       const sink = liveSink();
-      const att = (await registry.attach(chatId, undefined, 0, sink.cb))!;
+      const att = (await registry.attach(chatId, false, undefined, sink.cb))!;
       att.start();
 
       // Give streamText a beat to begin consuming the partial output.
@@ -543,9 +526,7 @@ describe('AiChatService run-stream attach [integration]', () => {
       expect(entry).toBeDefined();
       expect(entry.finished).toBe(true);
       const sink = liveSink();
-      // Finished with an EMPTY ring (aborted before any frame) -> null -> the
-      // client degrades to poll instead of hanging on an empty stream.
-      expect(await registry.attach(chatId, undefined, 0, sink.cb)).toBeNull();
+      expect(await registry.attach(chatId, false, undefined, sink.cb)).toBeNull();
     } finally {
       registry.onModuleDestroy();
       await cleanup();
@@ -575,8 +556,8 @@ describe('AiChatService run-stream attach [integration]', () => {
       });
       const sink = liveSink();
       // No entry was ever opened; attach always yields null.
-      expect(await registry.attach(chatId, undefined, 0, sink.cb)).toBeNull();
-      expect(await registry.attach(chatId, 'anything', 1, sink.cb)).toBeNull();
+      expect(await registry.attach(chatId, false, undefined, sink.cb)).toBeNull();
+      expect(await registry.attach(chatId, true, 'anything', sink.cb)).toBeNull();
     } finally {
       registry.onModuleDestroy();
       await cleanup();

apps/server/test/integration/page-history-idle-pipeline.int-spec.ts

@@ -0,0 +1,162 @@
+import { randomUUID } from 'node:crypto';
+import { Queue, Worker } from 'bullmq';
+import { PersistenceExtension } from '../../src/collaboration/extensions/persistence.extension';
+
+/**
+ * #370 — integration property of the idle-snapshot pipeline against REAL BullMQ.
+ *
+ * This is deliberately NOT a unit test of computeHistoryJob (that lives in
+ * compute-history-job.spec.ts). The point here is the OBSERVABLE end-to-end
+ * behaviour of the production `enqueuePageHistory` remove-then-add debounce
+ * driving a real Redis-backed delayed queue + worker (the #431→#439 class: a
+ * locally-correct function whose queue/timer property was never exercised):
+ *
+ *   - a CONTINUOUS burst of stores lasting several caps yields periodic idle
+ *     snapshots — at least one per max-wait cap, NOT one-per-store; and
+ *   - an INTERMITTENT burst (a few stores, then quiet) yields exactly ONE
+ *     trailing snapshot.
+ *
+ * We shrink the idle windows to milliseconds (jest.mock of collaboration
+ * constants) so real BullMQ delayed jobs actually promote within the test —
+ * fake timers cannot advance Redis's own delayed-set clock, so the intervals
+ * must be real but tiny. The production method under test is called verbatim.
+ */
+
+// NOTE: jest.mock is hoisted above the module's const initializers, so its
+// factory cannot close over MAX_WAIT_MS/INTERVAL_MS — the literals are inlined
+// here and MUST stay in sync with the consts below (a single source of truth is
+// impossible across the hoist boundary).
+jest.mock('../../src/collaboration/constants', () => {
+  const actual = jest.requireActual('../../src/collaboration/constants');
+  return {
+    ...actual,
+    IDLE_MAX_WAIT_USER: 300,
+    IDLE_MAX_WAIT_AGENT: 300,
+    IDLE_INTERVAL_USER: 1000,
+    IDLE_INTERVAL_AGENT: 1000,
+  };
+});
+
+// Mirrors the mocked IDLE_MAX_WAIT_* above (IDLE_INTERVAL_* is 1000 > this, so
+// the max-wait ceiling is what actually governs the trailing delay).
+const MAX_WAIT_MS = 300;
+
+const REDIS_CONNECTION = {
+  host: process.env.TEST_REDIS_HOST ?? '127.0.0.1',
+  port: Number(process.env.TEST_REDIS_PORT ?? 6379),
+};
+
+const sleep = (ms: number) => new Promise((r) => setTimeout(r, ms));
+
+describe('#370 idle-snapshot pipeline (real BullMQ)', () => {
+  let queue: Queue;
+  let worker: Worker;
+  let extension: PersistenceExtension;
+  // Every processed snapshot, tagged by pageId so the two scenarios stay isolated.
+  const processed: Array<{ pageId: string; kind: string; at: number }> = [];
+  const queueName = `history-idle-int-${randomUUID()}`;
+
+  beforeAll(async () => {
+    queue = new Queue(queueName, {
+      connection: REDIS_CONNECTION,
+      // Mirror the production default (BullModule.forRoot removeOnComplete): the
+      // enqueue idiom relies on the jobId being freed once a job completes so the
+      // next burst can re-arm the same id.
+      defaultJobOptions: { removeOnComplete: true, removeOnFail: true },
+    });
+    await queue.waitUntilReady();
+
+    worker = new Worker(
+      queueName,
+      async (job) => {
+        processed.push({
+          pageId: job.data?.pageId,
+          kind: job.data?.kind,
+          at: Date.now(),
+        });
+      },
+      { connection: REDIS_CONNECTION },
+    );
+    await worker.waitUntilReady();
+
+    // Construct the real extension; only historyQueue (5th ctor arg) and the
+    // internal idleBurstStart map are exercised by enqueuePageHistory, so the
+    // other collaborators can be null — the constructor only assigns fields.
+    extension = new PersistenceExtension(
+      null as any, // pageRepo
+      null as any, // pageHistoryRepo
+      null as any, // db
+      null as any, // aiQueue
+      queue as any, // historyQueue
+      null as any, // notificationQueue
+      null as any, // collabHistory
+      null as any, // transclusionService
+    );
+  });
+
+  afterAll(async () => {
+    // Force-close and fully drain so no BullMQ background activity (delayed-set
+    // polling, blocking BRPOPLPUSH) bleeds into later suites in this single
+    // shared jest worker (maxWorkers: 1).
+    await worker?.close(true).catch(() => undefined);
+    await queue?.obliterate({ force: true }).catch(() => undefined);
+    await queue?.close();
+    // Let the redis sockets settle before the next suite starts.
+    await sleep(150);
+  });
+
+  const arm = (pageId: string) =>
+    (extension as any).enqueuePageHistory({ id: pageId }, 'user');
+
+  it('continuous burst over several caps → periodic idle snapshots (≥1 per cap, not one-per-store)', async () => {
+    const pageId = randomUUID();
+    const runMs = 6 * MAX_WAIT_MS; // ~6 caps of unbroken editing
+    // Store cadence that does NOT evenly divide the cap: real hocuspocus stores
+    // are not aligned to cap boundaries, so a boundary job promotes in the gap
+    // before the next store's remove(). A cap-aligned cadence would instead land
+    // a store exactly on every boundary and lose the snapshot to the documented
+    // remove-vs-active race — an artefact of the test clock, not the pipeline.
+    const stepMs = 70;
+    const stores = Math.floor(runMs / stepMs);
+
+    const start = Date.now();
+    let count = 0;
+    while (Date.now() - start < runMs) {
+      await arm(pageId);
+      count++;
+      await sleep(stepMs);
+    }
+    // Let the final armed job flush.
+    await sleep(2 * MAX_WAIT_MS);
+
+    const snaps = processed.filter((p) => p.pageId === pageId);
+
+    // Every autosnapshot is an idle-kind row.
+    expect(snaps.every((s) => s.kind === 'idle')).toBe(true);
+    // Periodic: at least one per cap over a multi-cap burst (lower-bounded loosely
+    // to stay robust; the property is "fires at least every cap", not a single
+    // trailing snapshot).
+    expect(snaps.length).toBeGreaterThanOrEqual(3);
+    // But NOT one-per-store: ~`stores` stores were issued; the debounce must
+    // collapse them to a small multiple of the cap count, nowhere near per-store.
+    expect(snaps.length).toBeLessThanOrEqual(Math.ceil(stores / 2));
+  });
+
+  it('intermittent burst (a few stores, then quiet) → exactly ONE trailing snapshot', async () => {
+    const pageId = randomUUID();
+
+    // A short burst well within a single cap window, then silence.
+    await arm(pageId);
+    await sleep(40);
+    await arm(pageId);
+    await sleep(40);
+    await arm(pageId);
+
+    // Wait comfortably past the cap so the single pending trailing job fires.
+    await sleep(4 * MAX_WAIT_MS);
+
+    const snaps = processed.filter((p) => p.pageId === pageId);
+    expect(snaps).toHaveLength(1);
+    expect(snaps[0].kind).toBe('idle');
+  });
+});

apps/server/test/jest-integration.json

@@ -22,7 +22,6 @@
     "^@docmost/db/(.*)$": "<rootDir>/src/database/$1",
     "^@docmost/transactional/(.*)$": "<rootDir>/src/integrations/transactional/$1",
     "^@docmost/ee/(.*)$": "<rootDir>/src/ee/$1",
-    "^@docmost/token-estimate$": "<rootDir>/../../packages/token-estimate/src/index.ts",
     "^src/(.*)$": "<rootDir>/src/$1"
   }
 }

docs/features/page-work-time_design.md

@@ -387,7 +387,7 @@ bucketByDay(sessions, tz):
 факты ниже — ground truth, можно дозапросить файлы через gitea MCP по указанному SHA):
 
 - `page_history.kind` — `varchar(20)`, NULLABLE, БЕЗ дефолта (migration
-  `20260705T120000-page-history-kind.ts`). Домен: `manual`/`agent`/`idle`/`boundary`;
+  `20260707T120000-page-history-kind.ts`). Домен: `manual`/`agent`/`idle`/`boundary`;
   legacy `null` = автосейв (`collaboration/constants.ts`, `PageHistoryKind`).
 - `kind` УЖЕ включён в `PageHistoryRepo.baseFields` (`page-history.repo.ts`) — читается всеми
   выборками истории. `saveHistory({kind})` и `updateHistoryKind(id, kind)` существуют.

docs/reading-ai-logs.md

@@ -8,35 +8,19 @@ real pain (a "which tools fail most?" analysis that confidently answered
 
 Read the **Gotchas** section before you trust any error count.
 
-> **TWO ERAS — check the marker first.** The `tool_calls` shape changed in **#490
-> (trace v2)**. A row written by v2 carries `metadata.toolTraceVersion = 2`; older
-> rows have no such key. The two shapes store DIFFERENT things (v2 dropped the tool
-> OUTPUT from the trace), so **every query below is dual-shape** — branch on the
-> marker. **Never compare an aggregate or trend across the era boundary**: a metric
-> jump on the cut-over week is an artifact of the shape change, not a behavior
-> change.
-
 ## TL;DR
 
 - Agent chats live in Postgres, DB `docmost`, tables `ai_chat_*`.
-- **Era marker:** `metadata.toolTraceVersion = 2` ⇒ v2 (#490) row; absent ⇒ legacy row.
-- Each tool invocation is stored as **two** consecutive array elements — a
-  `tool-call` part then an OUTCOME part — so naive counting double-counts.
-  - **v2 (#490):** outcome is `{toolName, ok: true}` on success, or
-    `{toolName, error, kind: 'thrown'|'interrupted'}` on failure. The tool **OUTPUT
-    is NOT in `tool_calls`** any more — it lives once in `metadata.parts` (this
-    removed a hundreds-of-MB-per-run write duplication). Soft-failure analysis
-    therefore reads `metadata.parts`, not `tool_calls`.
-  - **legacy:** outcome is `{toolName, output}` on success; a **thrown** failure is
-    a `{toolName, error}` element **only on rows after #407**, and is dropped
-    entirely (silent orphan) on pre-#407 rows.
-- **A tool that *throws* writes no result part.** In v2 it is a
-  `{error, kind:'thrown'}` element; an interrupted/aborted call is a distinct
-  `{error, kind:'interrupted'}`. `isError`/`success=false` scans read the *output*
-  and so under-report thrown failures in every era.
-- To find where agents fail: (1) soft-failure markers in `metadata.parts` outputs
-  (v2) / `tool_calls` outputs (legacy), (2) the `error`/`kind` fields for thrown
-  failures (v2 + post-#407), (3) server logs / the live UI for full stack traces.
+- Each tool invocation is stored as **two** array elements (a `tool-call` part and
+  a `tool-result` part), so naive counting double-counts.
+- **A tool that *throws* writes no result part.** Since the #407 fix its error is
+  persisted as a dedicated `{toolName, error}` element in `tool_calls` (queryable +
+  replayed to the model). **Rows written before #407 still drop it** — the error is
+  nowhere in the DB and shows only in the live UI. So `isError` / `success=false`
+  scans under-report by design, and pre-#407 thrown errors are invisible.
+- To find where agents fail: (1) soft-failure markers in `tool_calls`, (2) the new
+  `error` field for thrown errors (new rows) / the orphan-gap proxy (old rows),
+  (3) server logs / the live UI for full stack traces beyond the truncated message.
 
 ## Where the data lives
 
@@ -69,67 +53,33 @@ are rows in `workspaces`, not separate deployments.
 separate `tool` role), `content` (text), `tool_calls` (jsonb array), `metadata`
 (jsonb, holds run `error` + rendered `parts`), `status`, `tsv` (full-text index).
 
-## Era marker — check this before every query
-
-```sql
--- how many rows are in each era?
-SELECT COALESCE((metadata->>'toolTraceVersion'), 'legacy') AS era, count(*)
-FROM ai_chat_messages
-WHERE role = 'assistant' AND jsonb_typeof(tool_calls) = 'array'
-GROUP BY 1 ORDER BY 2 DESC;
-```
-
-- `toolTraceVersion = '2'` → **v2** (#490): outcome flags, **no output in the trace**.
-- `NULL` (`'legacy'`) → pre-#490: outcome carries the tool `output` inline.
-
-**Do not trend a metric across the cut-over.** The shape change alone shifts counts
-(e.g. "elements with `output`" collapses to zero for v2), so a week that straddles
-the boundary shows an artifact, not a behavior change. Segment by era, or restrict to
-one era, before comparing.
-
 ## How tool calls are stored — READ THIS
 
 Tool calls are **not** one-object-per-call. Each logical invocation is split into
-two consecutive elements of the `tool_calls` array — a **call** then an **outcome**.
-The outcome shape is era-dependent:
+two consecutive elements of the `tool_calls` array:
 
 ```text
-# v2 (#490) — metadata.toolTraceVersion = 2
-index 0: { "toolName":"getPage", "input":{...} }                       ← call     (has input)
-index 1: { "toolName":"getPage", "ok":true }                          ← success  (NO output here)
-   or  : { "toolName":"getPage", "error":"…", "kind":"thrown" }       ← threw
-   or  : { "toolName":"getPage", "error":"…", "kind":"interrupted" }  ← aborted mid-step
-
-# legacy — no toolTraceVersion
-index 0: { "toolName":"getPage", "input":{...} }                       ← call     (has input, NO output)
-index 1: { "toolName":"getPage", "output":{...} }                     ← success  (has output)
-   or  : { "toolName":"getPage", "error":"…" }                        ← threw (post-#407 only)
+index 0: { "toolName": "getPage",  "input":  { "pageId": "…" } }   ← tool-call   (has input, NO output)
+index 1: { "toolName": "getPage",  "output": { … } }                ← tool-result (has output, NO input)
 ```
 
-The keys that can appear: `toolName`, `input` (call), and on the outcome — **v2:**
-`ok` **or** `error`+`kind`; **legacy:** `output` **or** (post-#407) `error`. There is
-no `state`, no `errorText`, no `type` in `tool_calls` (those live on `metadata.parts`).
-Consequences:
+The keys that appear on an element are `toolName`, `input`, `output`, and — for a
+**thrown** failure on rows written after the #407 fix — `error` (the tool's error
+message; see the "Hard failures" section below). There is no `state`, no `errorText`,
+no `type`. On pre-#407 rows a thrown failure has NO paired result element at all
+(silent orphan). Consequences:
 
-1. **Real invocation count** — count the OUTCOME elements, not every element (else you
-   double-count): **v2** = elements with `ok` or `error`; **legacy** = elements with
-   `output` or `error`.
-2. **Pairing:** a call (`input`) is followed by its outcome. `toolName` is on both, so
-   you can group by tool on either. In v2 the `kind` field separates a real hard-fail
-   (`thrown`) from an aborted call (`interrupted`) — a distinction legacy rows cannot
-   make (both are orphans; see below).
-3. **The tool OUTPUT is only in `metadata.parts` on v2 rows.** To inspect what a tool
-   returned (soft-error markers, page bodies) on a v2 row, read the parts
-   (`part->>'type' LIKE 'tool-%'`, `part->>'state' = 'output-available'`, `part->'output'`),
-   not `tool_calls`.
+1. **Real invocation count = elements that have `output` or `error`.** Counting every
+   element double-counts (you get ~2× and a spurious "~50% of every tool has no output").
+2. **Pairing:** a call = a `tool-call` part followed by its result part. A success
+   carries `output`; a thrown failure (post-#407) carries `error` instead. Both carry
+   `toolName`, so you can group by tool on either.
 
 ## The two classes of failure (and which the DB can see)
 
 ### 1. Soft failures — tool RAN and returned an error-shaped result → PERSISTED ✅
 
-These are visible in the tool `output` — **on v2 rows in `metadata.parts`** (the
-`output-available` part's `output`), on **legacy rows in the `tool_calls` outcome
-element's `output`**. The marker differs per tool:
+These are visible in the `tool-result` `output`. The marker differs per tool:
 
 | Tool(s) | Error marker in `output` |
 | --- | --- |
@@ -141,32 +91,37 @@ element's `output`**. The marker differs per tool:
 Note `editPageText` returns `failed: []` on success — filtering on the *presence*
 of the key gives false positives; filter on **non-empty**.
 
-### 2. Hard failures — tool THREW → PERSISTED ✅
+### 2. Hard failures — tool THREW → NOW PERSISTED ✅ (since the #407 fix)
 
 When a tool throws (the classic one is `patchNode` / `insertNode` / `tableUpdateCell`
 → `Failed to encode document to Yjs (fromJSON): Unknown node type: undefined`), the
-runtime writes **no `tool-result` part** — the failure is an ai@6 `tool-error` content
-part. How that lands in `tool_calls` depends on the era:
+runtime still writes **no `tool-result` part** — the failure is an ai@6 `tool-error`
+content part instead. **Since the #407 fix, that error is persisted**: `serializeSteps`
+appends a dedicated element `{toolName, error: "<message>"}` right after the failed
+call, mirroring how a successful `{toolName, output}` element is appended. So a thrown
+error now leaves a queryable `error` field carrying its (truncated) reason, and the
+same real text is replayed to the model on the next turn (an `output-error` part with
+the real `errorText`, no longer the `'Tool call did not complete.'` placeholder).
 
-- **v2 (#490):** a `{toolName, error, kind:'thrown'}` outcome element. An interrupted /
-  aborted mid-step call is a **distinct** `{toolName, error:'Tool call did not
-  complete.', kind:'interrupted'}` element — so you can tell a real hard-fail from an
-  abort **directly, without the orphan heuristic**. Query `kind = 'thrown'`.
-- **post-#407 legacy:** a `{toolName, error}` element (no `kind`) right after the call.
-- **pre-#407 legacy:** the error is **dropped** — a silent **orphan** (a `call` with no
-  `output` *and* no `error`).
+**Cutover caveat — old rows keep the old blind shape.** Rows written **before** this
+change have the two-part shape (`call` + `output` only) and simply **drop** thrown
+errors, leaving a silent **orphan** (a `call` with no `output` *and* no `error`). Rows
+written **after** the fix additionally carry the `error` element. So:
 
-The same real error text is replayed to the model on the next turn (an `output-error`
-part with the real `errorText`, from `metadata.parts`), in every era.
+- **New rows:** query the `error` field directly (see the hard-error query below) — no
+  orphan heuristic needed for thrown failures.
+- **Old rows (pre-#407):** the only DB-side proxy is still an **orphan**: a `tool-call`
+  part with no matching `tool-result` *and* no `error`. Orphans also appear when a run
+  is **aborted** mid-flight (server restart), so a high-volume tool (`createComment`,
+  `searchInPage`, `Search_web_search`) shows orphans from aborts, not real errors on
+  old rows. Treat the orphan gap as an *upper bound*, and cross-check the tool: a gap on
+  a structural editor (`patchNode`, `insertNode`, `updatePageJson`, `transformPage`) is
+  almost certainly a thrown Yjs-encode error; a gap on `createComment` is mostly aborts.
 
-**Cutover caveat.** Only pre-#407 legacy rows need the orphan proxy: an orphan is a
-`tool-call` with no matching outcome. Orphans there also appear when a run is **aborted**
-mid-flight (server restart), so a high-volume tool (`createComment`, `searchInPage`,
-`Search_web_search`) shows orphans from aborts, not real errors. Treat the orphan gap as
-an *upper bound* and cross-check the tool: a gap on a structural editor (`patchNode`,
-`insertNode`, `updatePageJson`, `transformPage`) is almost certainly a thrown Yjs-encode
-error; a gap on `createComment` is mostly aborts. **On v2 rows this ambiguity is gone**
-— `kind` labels each outcome.
+A note on the aborted-call fallback: a call with **neither** a result **nor** a
+`tool-error` (genuinely interrupted mid-step) still replays with the
+`'Tool call did not complete.'` placeholder and persists as an orphan — that path is
+unchanged, and is distinct from a real thrown error, which now carries `error`.
 
 ### 3. Run-level failures → `ai_chat_runs`
 
@@ -179,34 +134,22 @@ the wild: `Run interrupted by a server restart.` (aborts) and
 
 Run all of these via `docker exec gitmost-postgresql psql -U docmost -d docmost -P pager=off -c "…"`.
 
-**Real invocation count per tool** (outcome parts only — the correct denominator).
-Dual-shape: a v2 outcome has `ok` or `error`; a legacy outcome has `output` or `error`:
+**Real invocation count per tool** (result parts only — the correct denominator):
 
 ```sql
 SELECT elem->>'toolName' AS tool, count(*) AS calls
 FROM ai_chat_messages m, jsonb_array_elements(m.tool_calls) elem
-WHERE jsonb_typeof(m.tool_calls) = 'array'
-  AND (elem ? 'ok' OR elem ? 'output' OR elem ? 'error')
+WHERE jsonb_typeof(m.tool_calls) = 'array' AND elem ? 'output'
 GROUP BY 1 ORDER BY 2 DESC;
 ```
 
-**Soft errors per tool.** The soft-error marker lives in the tool OUTPUT — which on
-**v2 rows is in `metadata.parts`**, on **legacy rows is in the `tool_calls` outcome
-element**. This query UNIONs both eras, projecting each output as `o`:
+**Soft errors per tool** (everything the DB can honestly see):
 
 ```sql
 WITH res AS (
-  -- v2 (#490): output is in metadata.parts (output-available tool parts)
-  SELECT part->>'type' AS tool, part->'output' AS o
-  FROM ai_chat_messages m, jsonb_array_elements(m.metadata->'parts') part
-  WHERE (m.metadata->>'toolTraceVersion') = '2'
-    AND part->>'type' LIKE 'tool-%' AND part->>'state' = 'output-available'
-  UNION ALL
-  -- legacy: output is inline in the tool_calls outcome element
   SELECT elem->>'toolName' AS tool, elem->'output' AS o
   FROM ai_chat_messages m, jsonb_array_elements(m.tool_calls) elem
-  WHERE (m.metadata->>'toolTraceVersion') IS NULL
-    AND jsonb_typeof(m.tool_calls) = 'array' AND elem ? 'output'
+  WHERE jsonb_typeof(m.tool_calls) = 'array' AND elem ? 'output'
 )
 SELECT tool, count(*) AS calls,
        sum(COALESCE(
@@ -224,23 +167,13 @@ FROM res GROUP BY tool HAVING sum(COALESCE(
 ORDER BY soft_errors DESC;
 ```
 
-Note the v2 `tool` label is the part type (`tool-editPageText`); strip the `tool-`
-prefix if you join it against the legacy `toolName`.
-
-**`editPageText` failure reasons** (the most common real agent mistake — bad `find`).
-Same dual-shape output source:
+**`editPageText` failure reasons** (the most common real agent mistake — bad `find`):
 
 ```sql
 WITH res AS (
-  SELECT part->'output' AS o
-  FROM ai_chat_messages m, jsonb_array_elements(m.metadata->'parts') part
-  WHERE (m.metadata->>'toolTraceVersion') = '2'
-    AND part->>'type' = 'tool-editPageText' AND part->>'state' = 'output-available'
-  UNION ALL
   SELECT elem->'output' AS o
   FROM ai_chat_messages m, jsonb_array_elements(m.tool_calls) elem
-  WHERE (m.metadata->>'toolTraceVersion') IS NULL
-    AND jsonb_typeof(m.tool_calls) = 'array'
+  WHERE jsonb_typeof(m.tool_calls) = 'array'
     AND elem->>'toolName' = 'editPageText' AND elem ? 'output'
 )
 SELECT f->>'reason' AS reason, count(*)
@@ -249,43 +182,30 @@ WHERE jsonb_typeof(o->'failed') = 'array'
 GROUP BY 1 ORDER BY 2 DESC;
 ```
 
-**Hard errors — persisted `error` field per tool (v2 + post-#407 rows)** — thrown tool
-failures carry their real reason, so query them directly. On **v2** rows exclude the
-`interrupted` kind so an aborted call is not counted as a hard-fail:
+**Hard errors — persisted `error` field per tool (NEW rows, since #407)** — thrown
+tool failures now carry their real reason, so query them directly:
 
 ```sql
 SELECT elem->>'toolName' AS tool, count(*) AS thrown_errors,
        min(elem->>'error') AS sample_error
 FROM ai_chat_messages m, jsonb_array_elements(m.tool_calls) elem
 WHERE jsonb_typeof(m.tool_calls) = 'array' AND elem ? 'error'
-  -- v2 rows label the kind; a legacy error element has no kind (count it).
-  AND COALESCE(elem->>'kind', 'thrown') = 'thrown'
-GROUP BY 1 ORDER BY 2 DESC;
-```
-
-Aborted mid-step calls on v2 rows are a distinct, directly countable population:
-
-```sql
-SELECT elem->>'toolName' AS tool, count(*) AS interrupted
-FROM ai_chat_messages m, jsonb_array_elements(m.tool_calls) elem
-WHERE jsonb_typeof(m.tool_calls) = 'array' AND elem->>'kind' = 'interrupted'
 GROUP BY 1 ORDER BY 2 DESC;
 ```
 
 **Hard-error proxy for OLD rows (pre-#407) — orphan gap per tool, WITH a spread column**
-(call parts minus outcome parts, plus how many distinct chats the gap is spread across).
-This is needed ONLY for pre-#407 legacy rows (v2 and post-#407 rows carry the error /
-`kind` directly — use the queries above). The `WHERE` restricts to the legacy era so v2
-rows (where an `ok` outcome is not an `output`) never produce phantom orphans:
+(call parts minus result parts, plus how many distinct chats the gap is spread across).
+This covers rows written before thrown errors were persisted; on new rows a thrown
+failure now has its own `error` element (use the query above) and an orphan means only
+a genuinely aborted mid-step call:
 
 ```sql
 WITH parts AS (
   SELECT m.chat_id, elem->>'toolName' AS tool,
-         (elem ? 'input' AND NOT (elem ? 'output') AND NOT (elem ? 'ok')) AS is_call,
-         (elem ? 'output' OR elem ? 'error' OR elem ? 'ok')               AS is_result
+         (elem ? 'input' AND NOT (elem ? 'output')) AS is_call,
+         (elem ? 'output' OR elem ? 'error')        AS is_result
   FROM ai_chat_messages m, jsonb_array_elements(m.tool_calls) elem
   WHERE jsonb_typeof(m.tool_calls) = 'array' AND m.role = 'assistant'
-    AND (m.metadata->>'toolTraceVersion') IS NULL
 ),
 per_chat AS (
   SELECT tool, chat_id, sum(is_call::int) - sum(is_result::int) AS gap
@@ -341,21 +261,11 @@ WHERE tsv @@ websearch_to_tsquery('english', 'some phrase') LIMIT 20;
 
 ## Don't blow up your context
 
-Tool outputs embed full page content and search payloads (hundreds of KB per row).
-On **legacy** rows they are in `tool_calls`; on **v2** rows they moved to
-`metadata->'parts'` (the `tool_calls` trace itself is now small). Never `SELECT
-tool_calls` / `metadata` (or `jsonb_pretty(...)`) raw — project just the keys you need
-and truncate:
+A single `tool_calls` row can be **300–400 KB** (results embed full page content and
+search payloads). Never `SELECT tool_calls` (or `jsonb_pretty(tool_calls)`) raw.
+Always project just the keys you need and truncate:
 
 ```sql
--- v2: outputs live in metadata.parts
-SELECT part->>'type',
-       left(regexp_replace((part->'output')::text, '\s+', ' ', 'g'), 200)
-FROM ai_chat_messages m, jsonb_array_elements(m.metadata->'parts') part
-WHERE (m.metadata->>'toolTraceVersion') = '2'
-  AND part->>'state' = 'output-available' LIMIT 5;
-
--- legacy: outputs live in tool_calls
 SELECT elem->>'toolName',
        left(regexp_replace((elem->'output')::text, '\s+', ' ', 'g'), 200)
 FROM ai_chat_messages m, jsonb_array_elements(m.tool_calls) elem
@@ -370,32 +280,26 @@ docker compose -p gitmost logs -f --tail=100 # whole stack
 ```
 
 Logging is `json-file`, `max-size=10m max-file=5` → ~50 MB retained, then rotated,
-and **wiped on container recreate**. Thrown-tool error text is **persisted** — in the
-`error` field of `tool_calls` (v2 `kind:'thrown'` / post-#407 legacy) — so you no longer
-depend on live logs for it. Logs/live UI remain useful for **pre-#407 rows** (whose
-thrown errors were dropped) and for full stack traces beyond the truncated stored
-message. A per-tool `tool_calls_total{tool,status}` metric to VictoriaMetrics is still a
-possible future add for aggregate dashboards.
+and **wiped on container recreate**. Since the #407 fix, thrown-tool error text is
+**persisted in the `error` field** of `tool_calls` (see the hard-error query above), so
+you no longer depend on live logs for it. Logs/live UI remain useful for **pre-#407
+rows** (whose thrown errors were dropped) and for full stack traces beyond the
+truncated stored message. A per-tool `tool_calls_total{tool,status}` metric to
+VictoriaMetrics is still a possible future add for aggregate dashboards.
 
 ## Gotchas checklist
 
-- [ ] **Check `metadata.toolTraceVersion` first.** v2 (`= 2`) has no output in `tool_calls`; legacy has it inline. Never trend a metric across the era boundary.
-- [ ] Counting every `tool_calls` element → **overcount**. Count OUTCOME elements — v2: `ok` or `error`; legacy: `output` or `error` — never both call+outcome as invocations.
-- [ ] `isError` / `success=false` ≈ 0 does **not** mean "no errors" — thrown errors are an `error` element (v2 `kind:'thrown'` / post-#407), not in the output.
-- [ ] **v2:** soft-error markers (the tool output) are in `metadata.parts`, NOT `tool_calls`. Legacy: they are in the `tool_calls` outcome `output`.
-- [ ] **v2:** `kind` splits a real hard-fail (`thrown`) from an aborted call (`interrupted`) directly — no orphan heuristic needed. The orphan gap is a pre-#407-legacy-only proxy.
+- [ ] Counting every `tool_calls` element → **overcount**. Count `output` elements; add `error` elements for thrown failures (new rows), but don't count both as invocations.
+- [ ] `isError` / `success=false` ≈ 0 does **not** mean "no errors" — thrown errors are a separate `error` element (new rows) or dropped entirely (pre-#407 rows).
+- [ ] Thrown errors persist only on rows written **after the #407 fix** — pre-#407 rows still drop them (orphan only). Mind the cutover when trending over time.
 - [ ] `editPageText.failed` is `[]` on success — test for **non-empty**, not presence.
+- [ ] Orphan gap on OLD rows mixes thrown errors **and** aborted runs — split by tool. On NEW rows a thrown error is its own `error` element, so a gap ≈ aborted call.
 - [ ] `aborted` runs = server restarts, `failed` runs = provider overload — not agent mistakes.
-- [ ] Never dump a raw `tool_calls` **or** `metadata.parts` cell — outputs are hundreds of KB.
-- [ ] Logs are ephemeral (≤50 MB, wiped on recreate) — grab pre-#407 hard-error text live.
+- [ ] Never dump a raw `tool_calls` cell — it can be hundreds of KB.
+- [ ] Logs are ephemeral (≤50 MB, wiped on recreate) — grab hard-error text live.
 
 ## Snapshot (2026-07-07, illustrative — rerun the queries for current numbers)
 
-> All rows in this snapshot predate #490, so they are **legacy-era** (outputs inline in
-> `tool_calls`, orphan proxy for thrown errors). Do not trend these numbers against v2
-> rows — segment by `toolTraceVersion` first.
-
-
 - 226 chats, 732 messages, 46 runs; ~4 400 real tool invocations.
 - Soft errors (persisted): `editPageText` 4/79 (bad/non-unique `find`) + 9 markdown-in-`find` warnings; `semanticSearch` 3/4 (`unavailable`); `Habr_update_draft_from_docmost` 1/2 (`doc` sent as object, not string).
 - Missing-result proxy, read WITH the spread column:

packages/mcp/src/client/comments.ts

@@ -59,39 +59,6 @@ import {
   mergeFootnoteDefinitions,
 } from "../lib/transforms.js";
 
-// Max concurrent per-page comment fetches in checkNewComments (#490). The scan is
-// O(N) independent REST reads over the working set; running them one-at-a-time made
-// a large space linear in round-trips. A small cap parallelizes without hammering
-// the server (or exhausting sockets). 6 is a conservative middle of the 5–8 band.
-const COMMENT_SCAN_CONCURRENCY = 6;
-
-/**
- * Map `items` through `fn` with at most `limit` in flight, preserving INPUT ORDER
- * in the returned array. A tiny bounded pool (no p-limit dependency): `limit`
- * workers pull the next index off a shared cursor until the list is drained.
- */
-async function mapWithConcurrency<T, R>(
-  items: readonly T[],
-  limit: number,
-  fn: (item: T, index: number) => Promise<R>,
-): Promise<R[]> {
-  const results = new Array<R>(items.length);
-  let cursor = 0;
-  const worker = async (): Promise<void> => {
-    for (;;) {
-      const i = cursor++;
-      if (i >= items.length) return;
-      results[i] = await fn(items[i], i);
-    }
-  };
-  const workers = Array.from(
-    { length: Math.max(1, Math.min(limit, items.length)) },
-    () => worker(),
-  );
-  await Promise.all(workers);
-  return results;
-}
-
 // Public method surface of CommentsMixin (issue #450) — a NAMED type so the factory
 // return type is expressible in the emitted .d.ts (the anonymous mixin class
 // carries the base's protected shared state, which would otherwise trip TS4094).
@@ -688,32 +655,27 @@ export function CommentsMixin<TBase extends GConstructor<DocmostClientContext>>(
       parentPageId,
     );
 
-    // 2. Fetch comments for each page, keep ones created after since. Runs with
-    // bounded concurrency (#490) instead of one-at-a-time — the per-page reads are
-    // independent, so a large working set no longer costs O(N) serial round-trips.
-    // Order is preserved (mapWithConcurrency keeps input order), so the output is
-    // deterministic regardless of which fetch finishes first.
-    const perPage = await mapWithConcurrency(
-      pagesInScope,
-      COMMENT_SCAN_CONCURRENCY,
-      async (page: any) => {
-        try {
-          // Full feed (incl. resolved): a "new comments since" scan reports all
-          // recent activity; the active-only filter is scoped to listComments.
-          const comments = (await this.listComments(page.id, true)).items;
-          const newComments = comments.filter(
-            (c: any) => new Date(c.createdAt) > sinceDate,
-          );
-          return newComments.length > 0
-            ? { pageId: page.id, pageTitle: page.title, comments: newComments }
-            : null;
-        } catch (e: any) {
-          // Skip pages with errors (e.g. deleted between calls)
-          return null;
+    // 2. Fetch comments for each page, keep ones created after since
+    const results: any[] = [];
+    for (const page of pagesInScope) {
+      try {
+        // Full feed (incl. resolved): a "new comments since" scan reports all
+        // recent activity; the active-only filter is scoped to listComments.
+        const comments = (await this.listComments(page.id, true)).items;
+        const newComments = comments.filter(
+          (c: any) => new Date(c.createdAt) > sinceDate,
+        );
+        if (newComments.length > 0) {
+          results.push({
+            pageId: page.id,
+            pageTitle: page.title,
+            comments: newComments,
+          });
         }
-      },
-    );
-    const results: any[] = perPage.filter((r): r is any => r !== null);
+      } catch (e: any) {
+        // Skip pages with errors (e.g. deleted between calls)
+      }
+    }
 
     const totalNewComments = results.reduce(
       (sum, r) => sum + r.comments.length,

packages/mcp/test/mock/pagination-cursor.test.mjs

@@ -442,139 +442,3 @@ test("checkNewComments subtree includes the root without a separate getPageRaw",
   assert.equal(result.checkedPages, 2, "root + one descendant scanned");
   assert.equal(result.totalNewComments, 1, "the root's fresh comment found");
 });
-
-// -----------------------------------------------------------------------------
-// 6) checkNewComments parallelism (#490): the per-page comment fetches run with
-//    bounded concurrency (not one-at-a-time), and the results still preserve the
-//    page order deterministically regardless of which fetch finishes first.
-// -----------------------------------------------------------------------------
-test("checkNewComments fetches pages concurrently (bounded) and preserves order", async () => {
-  // A subtree with 12 descendants so the scan has plenty to parallelize.
-  const NODES = [{ id: "parent", title: "Parent", parentPageId: null, hasChildren: true }];
-  for (let i = 0; i < 12; i++) {
-    NODES.push({ id: `k${i}`, title: `Kid ${i}`, parentPageId: "parent", hasChildren: false });
-  }
-
-  let inFlight = 0;
-  let maxInFlight = 0;
-
-  const { baseURL } = await spawn(async (req, res) => {
-    const raw = await readBody(req);
-    if (handleLogin(req, res)) return;
-    if (req.url === "/api/pages/tree") {
-      sendJson(res, 200, { success: true, data: { items: NODES } });
-      return;
-    }
-    if (req.url === "/api/comments") {
-      const body = JSON.parse(raw || "{}");
-      inFlight++;
-      maxInFlight = Math.max(maxInFlight, inFlight);
-      // Hold the response briefly so concurrent fetches actually overlap.
-      setTimeout(() => {
-        inFlight--;
-        // Every page carries one fresh comment so ordering is observable.
-        sendJson(res, 200, {
-          success: true,
-          data: {
-            items: [
-              { id: `c-${body.pageId}`, createdAt: "2030-01-01T00:00:00.000Z", content: null },
-            ],
-            meta: { nextCursor: null },
-          },
-        });
-      }, 25);
-      return;
-    }
-    sendJson(res, 404, {});
-  });
-
-  const client = new DocmostClient(baseURL, "user@example.com", "pw");
-  const result = await client.checkNewComments(
-    "space-1",
-    "2020-01-01T00:00:00.000Z",
-    "parent",
-  );
-
-  // 13 pages (parent + 12 kids) were scanned; each had a fresh comment.
-  assert.equal(result.checkedPages, 13, "all pages scanned");
-  assert.equal(result.totalNewComments, 13, "one fresh comment per page");
-  // Parallelism: more than one request was in flight at once, but never above the
-  // cap (6). A serial implementation would show maxInFlight === 1.
-  assert.ok(maxInFlight > 1, `expected concurrent fetches, saw max ${maxInFlight}`);
-  assert.ok(maxInFlight <= 6, `concurrency must be bounded, saw ${maxInFlight}`);
-  // Deterministic order: results follow the page-enumeration order (parent first).
-  assert.equal(result.comments[0].pageId, "parent", "results preserve page order");
-  assert.deepEqual(
-    result.comments.map((r) => r.pageId),
-    ["parent", ...Array.from({ length: 12 }, (_, i) => `k${i}`)],
-    "result order matches the enumeration order regardless of finish order",
-  );
-});
-
-// -----------------------------------------------------------------------------
-// 7) checkNewComments partial failure (#490): the concurrent scan is resilient —
-//    if ONE page's /comments fetch rejects (deleted mid-scan, a transient 500),
-//    that page is skipped and the WHOLE scan still resolves with every other
-//    page's fresh comments. A single failing fetch must never reject the batch
-//    (Promise.all in mapWithConcurrency would otherwise abort all of it) nor
-//    corrupt the deterministic order of the pages that DID succeed.
-// -----------------------------------------------------------------------------
-test("checkNewComments skips a page whose fetch fails and still reports the rest", async () => {
-  const NODES = [{ id: "parent", title: "Parent", parentPageId: null, hasChildren: true }];
-  for (let i = 0; i < 5; i++) {
-    NODES.push({ id: `k${i}`, title: `Kid ${i}`, parentPageId: "parent", hasChildren: false });
-  }
-  // The one page whose comment fetch blows up (500 -> listComments rejects).
-  const FAILING = "k2";
-
-  const { baseURL } = await spawn(async (req, res) => {
-    const raw = await readBody(req);
-    if (handleLogin(req, res)) return;
-    if (req.url === "/api/pages/tree") {
-      sendJson(res, 200, { success: true, data: { items: NODES } });
-      return;
-    }
-    if (req.url === "/api/comments") {
-      const body = JSON.parse(raw || "{}");
-      if (body.pageId === FAILING) {
-        // A transient server error on exactly one page's fetch.
-        sendJson(res, 500, { success: false, message: "boom" });
-        return;
-      }
-      sendJson(res, 200, {
-        success: true,
-        data: {
-          items: [
-            { id: `c-${body.pageId}`, createdAt: "2030-01-01T00:00:00.000Z", content: null },
-          ],
-          meta: { nextCursor: null },
-        },
-      });
-      return;
-    }
-    sendJson(res, 404, {});
-  });
-
-  const client = new DocmostClient(baseURL, "user@example.com", "pw");
-  // Must RESOLVE (not reject) despite one page's fetch failing.
-  const result = await client.checkNewComments(
-    "space-1",
-    "2020-01-01T00:00:00.000Z",
-    "parent",
-  );
-
-  // Every page in scope was still scanned (the failing one counts as checked).
-  assert.equal(result.checkedPages, 6, "all pages scanned incl. the failing one");
-  // The failing page contributes nothing; the other 5 each report one comment.
-  assert.equal(result.pagesWithNewComments, 5, "the failing page is dropped");
-  assert.equal(result.totalNewComments, 5, "only the succeeding pages' comments");
-  const reportedIds = result.comments.map((r) => r.pageId);
-  assert.ok(!reportedIds.includes(FAILING), "the failing page is absent from results");
-  // Order of the survivors is still the deterministic enumeration order (the hole
-  // left by the failing page is closed without reordering the rest).
-  assert.deepEqual(
-    reportedIds,
-    ["parent", "k0", "k1", "k3", "k4"],
-    "survivors keep enumeration order with the failing page removed",
-  );
-});

packages/token-estimate/package.json

@@ -1,19 +0,0 @@
-{
-  "name": "@docmost/token-estimate",
-  "version": "0.1.0",
-  "description": "Shared, provider-agnostic token estimator (chars/2.5) used by the AI-chat client counter and the server history-replay budgeter, so the two never diverge.",
-  "private": true,
-  "main": "./dist/index.js",
-  "types": "./dist/index.d.ts",
-  "scripts": {
-    "build": "tsc",
-    "watch": "tsc --watch",
-    "test": "vitest run",
-    "test:watch": "vitest"
-  },
-  "license": "MIT",
-  "devDependencies": {
-    "typescript": "^5.0.0",
-    "vitest": "4.1.6"
-  }
-}

packages/token-estimate/src/index.test.ts

@@ -1,31 +0,0 @@
-import { describe, it, expect } from 'vitest';
-import { estimateTokens, CHARS_PER_TOKEN } from './index';
-
-describe('estimateTokens (shared chars/2.5)', () => {
-  it('returns 0 for empty / nullish input', () => {
-    expect(estimateTokens('')).toBe(0);
-    expect(estimateTokens(null)).toBe(0);
-    expect(estimateTokens(undefined)).toBe(0);
-  });
-
-  it('uses the chars/2.5 ratio, ceiled', () => {
-    expect(CHARS_PER_TOKEN).toBe(2.5);
-    // 5 chars / 2.5 = 2
-    expect(estimateTokens('abcde')).toBe(2);
-    // any non-empty string is at least 1 token (ceil)
-    expect(estimateTokens('a')).toBe(1);
-    // 100 chars / 2.5 = 40
-    expect(estimateTokens('x'.repeat(100))).toBe(40);
-  });
-
-  it('counts Cyrillic ~2x higher than the old chars/4 rule (no undercount)', () => {
-    const cyr = 'привет мир как дела'; // 19 chars
-    expect(estimateTokens(cyr)).toBe(Math.ceil(19 / 2.5)); // 8
-    expect(estimateTokens(cyr)).toBeGreaterThan(Math.ceil(19 / 4)); // > 5
-  });
-
-  it('is deterministic / byte-stable (same input => same output)', () => {
-    const s = 'the quick brown fox';
-    expect(estimateTokens(s)).toBe(estimateTokens(s));
-  });
-});

packages/token-estimate/src/index.ts

@@ -1,35 +0,0 @@
-/**
- * Shared, provider-agnostic token estimator (#490).
- *
- * No provider exposes an exact tokenizer we can afford to run on the hot path (a
- * real BPE pass is O(n²)-ish, bloats the client bundle, and is wrong for
- * Gemini/Ollama anyway), so both the client's in-body counter AND the server's
- * history-replay budgeter use this ONE cheap chars-based heuristic. Keeping it in
- * a single shared module is deliberate: two independent estimators drift, and then
- * "the badge shows 60%" while "the budgeter already trimmed" — the exact confusion
- * this package prevents.
- *
- * Ratio: **chars / 2.5**. Most content here is Cyrillic, where a token is ~2.5
- * characters; the common English `chars/4` rule of thumb UNDER-counts Cyrillic by
- * ~2×, which for a budget check is the dangerous direction (it lets the context
- * overflow). 2.5 slightly over-estimates pure English/code, which is the SAFE
- * direction for a budget. This is an estimate, never an exact count — the
- * authoritative figure is always the provider's reported usage; the estimate is
- * for UI affordances, the delta of not-yet-sent messages, and deciding what to
- * trim.
- */
-
-/** Characters per token for the shared estimate. See the module comment. */
-export const CHARS_PER_TOKEN = 2.5;
-
-/**
- * Rough token estimate for a piece of text (chars / {@link CHARS_PER_TOKEN}).
- * Returns 0 for empty/nullish input, and ceils so any non-empty text counts as at
- * least one token. Pure and deterministic (byte-stable), so the same text always
- * yields the same estimate — which the server budgeter relies on to keep replay
- * trimming stable turn to turn (provider prompt-cache friendliness).
- */
-export function estimateTokens(text: string | null | undefined): number {
-  if (!text) return 0;
-  return Math.ceil(text.length / CHARS_PER_TOKEN);
-}

packages/token-estimate/tsconfig.json

@@ -1,16 +0,0 @@
-{
-  "compilerOptions": {
-    "target": "ES2022",
-    "module": "CommonJS",
-    "moduleResolution": "Node",
-    "outDir": "./dist",
-    "rootDir": "./src",
-    "strict": true,
-    "esModuleInterop": true,
-    "skipLibCheck": true,
-    "forceConsistentCasingInFileNames": true,
-    "declaration": true
-  },
-  "include": ["src/**/*"],
-  "exclude": ["src/**/*.test.ts"]
-}

pnpm-lock.yaml

@@ -287,9 +287,6 @@ importers:
       '@docmost/prosemirror-markdown':
         specifier: workspace:*
         version: link:../../packages/prosemirror-markdown
-      '@docmost/token-estimate':
-        specifier: workspace:*
-        version: link:../../packages/token-estimate
       '@excalidraw/excalidraw':
         specifier: 0.18.0-3a5ef40
         version: 0.18.0-3a5ef40(@types/react-dom@18.3.1)(@types/react@18.3.12)(react-dom@18.3.1(react@18.3.1))(react@18.3.1)
@@ -564,9 +561,6 @@ importers:
       '@docmost/prosemirror-markdown':
         specifier: workspace:*
         version: link:../../packages/prosemirror-markdown
-      '@docmost/token-estimate':
-        specifier: workspace:*
-        version: link:../../packages/token-estimate
       '@fastify/compress':
         specifier: ^9.0.0
         version: 9.0.0
@@ -1154,15 +1148,6 @@ importers:
         specifier: 4.1.6
         version: 4.1.6(@opentelemetry/api@1.9.0)(@types/node@20.19.43)(@vitest/coverage-v8@4.1.6)(happy-dom@20.8.9)(jsdom@25.0.0)(vite@8.0.5(@types/node@20.19.43)(esbuild@0.28.0)(jiti@2.4.2)(less@4.2.0)(sugarss@5.0.1(postcss@8.5.14))(terser@5.39.0)(tsx@4.21.0)(yaml@2.8.3))
 
-  packages/token-estimate:
-    devDependencies:
-      typescript:
-        specifier: ^5.0.0
-        version: 5.9.3
-      vitest:
-        specifier: 4.1.6
-        version: 4.1.6(@opentelemetry/api@1.9.0)(@types/node@25.5.0)(@vitest/coverage-v8@4.1.6)(happy-dom@20.8.9)(jsdom@27.4.0(@noble/hashes@2.0.1))(vite@8.0.5(@types/node@25.5.0)(esbuild@0.28.0)(jiti@2.4.2)(less@4.2.0)(sugarss@5.0.1(postcss@8.5.14))(terser@5.39.0)(tsx@4.21.0)(yaml@2.8.3))
-
 packages:
 
   '@aashutoshrathi/word-wrap@1.2.6':