fix(web-shell): bound daemon transcript retention to stop renderer OOM crashes

packages/sdk-typescript/scripts/build.js

@@ -93,13 +93,25 @@ const rootDir = join(__dirname, '..');
 // Bumped from 195KB to 196KB for transient-vs-gone media hydration errors and
 // the reference-only replay placeholder.
 // Bumped from 196KB to 197KB for the workspace session live-state daemon
-// surface (catalog version + live snapshot accessors) and immutable,
-// identity-stable transcript block indexes used by browser renderers.
+// surface (catalog version + live snapshot accessors), immutable,
+// identity-stable transcript block indexes used by browser renderers, and the
+// daemon transcript-retention work (replay-snapshot release + capped debug
+// payloads, #9303) landing on top of the session media references bundle.
 // Bumped from 197KB to 198KB for the unrecognized-diagnostic sidechannel
 // (`unrecognizedDiagnostics` routing + selector, #8823).
 // Bumped from 198KB to 199KB for persistent session attachment read/remove and
 // binary resource hydration.
-const MAX_DAEMON_BROWSER_BUNDLE_BYTES = 199 * 1024;
+// Bumped from 199KB to 200KB for the retention byte budget (block byte
+// estimation + budget-aware trimming) and backing-store-detached string caps
+// (#9303 review round 3).
+// Bumped from 200KB to 206KB for the pagination/eviction reconciliation and the
+// #8823 × #9303 merge (#9303 review rounds 9-12): eviction-direction signal,
+// rewind truncation callback, trimmed tool/permission sentinel helpers,
+// record-boundary eviction snap, and the floor back-off — each bump budgeted
+// its own delta in isolation, and the combined feature sets land here. The
+// attachment read/remove + binary hydration feature that separately bumped
+// main to 199KB merges within this headroom, so no further bump is needed.
+const MAX_DAEMON_BROWSER_BUNDLE_BYTES = 206 * 1024;
 // The opt-in `daemon/transports` browser bundle legitimately ships the concrete
 // ACP transports (AcpHttpTransport/AcpWsTransport/AutoReconnect + negotiate), so
 // it's larger than the default barrel — but still budgeted so a future PR can't

packages/sdk-typescript/src/daemon/DaemonSessionClient.ts

@@ -171,7 +171,13 @@ export class DaemonSessionClient {
   readonly client: DaemonClient;
   readonly session: DaemonSession;
   readonly state: DaemonSessionState;
-  readonly replaySnapshot: DaemonReplaySnapshot;
+  /**
+   * Not `readonly`: {@link consumeReplaySnapshot} swaps it for an empty
+   * snapshot once the provider has injected it into the transcript store,
+   * releasing the raw wire events (tens of MiB on busy sessions) instead of
+   * retaining them for the session client's lifetime.
+   */
+  replaySnapshot: DaemonReplaySnapshot;
   readonly replaySnapshotComplete: boolean;
   readonly replayPartial: boolean;
   readonly replayError: string | undefined;
@@ -405,6 +411,19 @@ export class DaemonSessionClient {
     return this.lastSeenEpoch;
   }
 
+  /**
+   * Returns the retained replay snapshot and drops the client's reference
+   * to it. Call once the snapshot has been injected into a transcript
+   * store; the raw wire events are no longer needed (SSE continues from
+   * `lastEventId`, and older history is served by pagination) and can
+   * otherwise pin tens of MiB per session client.
+   */
+  consumeReplaySnapshot(): DaemonReplaySnapshot {
+    const snapshot = this.replaySnapshot;
+    this.replaySnapshot = { compactedReplay: [], liveJournal: [] };
+    return snapshot;
+  }
+
   setLastEventId(lastEventId: number | undefined): void {
     this.lastSeenEventId = validateLastEventId(lastEventId);
   }

packages/sdk-typescript/src/daemon/index.ts

@@ -100,13 +100,16 @@ export {
   daemonBlockToPlainText,
   daemonToolPreviewToMarkdown,
   daemonUiEventToTerminalText,
+  estimateDaemonTranscriptBlockBytes,
   extractContentPart,
   extractServerTimestamp,
   formatBlockTimestamp,
   getOutputText as getDaemonUiOutputText,
   getSessionUpdatePayload,
   isDaemonUiSensitiveKey,
   isSubagentChildBlock,
+  isTrimmedPermissionBlockId,
+  isTrimmedToolBlockId,
   isUnrecognizedDiagnosticReason,
   normalizeDaemonEvent,
   redactDaemonUiSensitiveFields,
@@ -159,6 +162,7 @@ export type {
   DaemonTranscriptSidechannelState,
   DaemonTranscriptState,
   DaemonTranscriptStore,
+  DaemonTranscriptTruncationDetail,
   DaemonUiAssistantDoneEvent,
   DaemonUiAuthDeviceFlowAuthorizedEvent,
   DaemonUiAuthDeviceFlowCancelledEvent,

packages/sdk-typescript/src/daemon/ui/chat-record-transcript.ts

@@ -105,6 +105,13 @@ export function projectChatRecordsToDaemonTranscript(
   let truncated = false;
   let state = createDaemonTranscriptState({
     maxBlocks,
+    // Trim-free by bytes: this offline/export projection's only documented
+    // truncation knob is `maxBlocks`. The retention byte budget exists for
+    // the LIVE session window; applying it here would silently evict older
+    // blocks from rendered/exported transcripts whose `maxBlocks` never
+    // limited them, and the truncation diagnostic would misname maxBlocks as
+    // the cause.
+    maxRetainedBytes: Number.POSITIVE_INFINITY,
     now: 0,
     onTruncation: (detail) => {
       truncated = true;

packages/sdk-typescript/src/daemon/ui/index.ts

@@ -13,8 +13,11 @@ export { createDaemonToolPreview } from './toolPreview.js';
 export {
   appendLocalUserTranscriptMessage,
   createDaemonTranscriptState,
+  estimateDaemonTranscriptBlockBytes,
   formatBlockTimestamp,
   isSubagentChildBlock,
+  isTrimmedPermissionBlockId,
+  isTrimmedToolBlockId,
   rebuildDaemonTranscriptBlockIndex,
   reduceDaemonTranscriptEvents,
   selectApprovalMode,
@@ -88,6 +91,7 @@ export type {
   DaemonTranscriptSidechannelState,
   DaemonTranscriptState,
   DaemonTranscriptStore,
+  DaemonTranscriptTruncationDetail,
   DaemonUnrecognizedDiagnostic,
   DaemonUnrecognizedDiagnosticReason,
   // Chat-stream events

packages/sdk-typescript/src/daemon/ui/normalizer.ts

@@ -22,6 +22,7 @@ import type {
 } from './types.js';
 import { DAEMON_PLAN_TOOL_CALL_ID } from './types.js';
 import {
+  capDetails,
   getFirstString,
   getOutputText,
   getString,
@@ -59,7 +60,6 @@ const MCP_RESTART_REFUSED_REASONS = new Set<string>([
 ]);
 
 const MALFORMED_MEMORY_CHANGED = 'malformed memory_changed payload';
-const MAX_DETAILS_LENGTH = 4096;
 const SESSION_RECORDING_DEGRADED_MESSAGE =
   'Session recording stopped after a write failure. New messages for the affected session will not be saved. Check disk space and permissions, then start a new session to resume recording.';
 
@@ -407,7 +407,10 @@ function normalizeUnrecognizedEvent(
       ...base,
       type: 'debug',
       debugReason: 'unrecognized_event',
-      text: `${event.type} (unrecognized daemon event): ${stringifyRedactedJson(event.data)}`,
+      text: debugBlockText(
+        `${event.type} (unrecognized daemon event)`,
+        event.data,
+      ),
     },
   ];
 }
@@ -768,7 +771,7 @@ function normalizeSessionUpdate(
         ...base,
         type: 'debug',
         debugReason: 'malformed_payload',
-        text: `session_update: ${stringifyRedactedJson(event.data)}`,
+        text: debugBlockText('session_update', event.data),
       },
     ];
   }
@@ -981,7 +984,7 @@ function normalizeSessionUpdate(
           debugReason: kind?.trim()
             ? 'unrecognized_session_update'
             : 'malformed_payload',
-          text: `${kind ?? 'session_update'}: ${stringifyRedactedJson(update)}`,
+          text: debugBlockText(kind ?? 'session_update', update),
         },
       ];
   }
@@ -1256,9 +1259,15 @@ function asDaemonErrorKind(
     : undefined;
 }
 
-function capDetails(details: string): string {
-  if (details.length <= MAX_DETAILS_LENGTH) return details;
-  return `${details.slice(0, MAX_DETAILS_LENGTH)}... [truncated]`;
+/**
+ * Builds the `text` of a `debug` block that embeds an unrecognized or
+ * malformed payload, capped at the producer. One such block is appended per
+ * frame, so a high-frequency frame could otherwise accumulate 100KB blocks up
+ * to the transcript block cap; capping here means a future debug branch
+ * cannot drop the cap.
+ */
+function debugBlockText(prefix: string, data: unknown): string {
+  return capDetails(`${prefix}: ${stringifyRedactedJson(data)}`);
 }
 
 function normalizePermissionRequest(
@@ -1271,7 +1280,7 @@ function normalizePermissionRequest(
         ...base,
         type: 'debug',
         debugReason: 'malformed_payload',
-        text: `permission_request: ${stringifyRedactedJson(event.data)}`,
+        text: debugBlockText('permission_request', event.data),
       },
     ];
   }
@@ -1283,7 +1292,7 @@ function normalizePermissionRequest(
         ...base,
         type: 'debug',
         debugReason: 'malformed_payload',
-        text: `permission_request: ${stringifyRedactedJson(event.data)}`,
+        text: debugBlockText('permission_request', event.data),
       },
     ];
   }
@@ -1317,7 +1326,7 @@ function normalizePermissionResolved(
         ...base,
         type: 'debug',
         debugReason: 'malformed_payload',
-        text: `${event.type}: ${stringifyRedactedJson(event.data)}`,
+        text: debugBlockText(event.type, event.data),
       },
     ];
   }

packages/sdk-typescript/src/daemon/ui/store.ts

@@ -6,21 +6,30 @@
 
 import type {
   DaemonTextDeltaMeta,
+  DaemonTranscriptReducerOptions,
   DaemonTranscriptState,
   DaemonTranscriptStore,
   DaemonUiEvent,
 } from './types.js';
 import {
   appendLocalUserTranscriptMessage,
   createDaemonTranscriptState,
+  estimateDaemonTranscriptBlockBytes,
   rebuildDaemonTranscriptBlockIndex,
   reduceDaemonTranscriptEvents,
 } from './transcript.js';
 
 export function createDaemonTranscriptStore(
-  seed: Partial<DaemonTranscriptState> = {},
+  seed: Partial<DaemonTranscriptState> &
+    Pick<DaemonTranscriptReducerOptions, 'onTruncation'> = {},
 ): DaemonTranscriptStore {
-  let state = createState(seed);
+  // Held in the closure (not on the state object) so `reset()` keeps the
+  // listener registered across wholesale state replacements.
+  const { onTruncation, ...stateSeed } = seed;
+  const reducerOptions: DaemonTranscriptReducerOptions = onTruncation
+    ? { onTruncation }
+    : {};
+  let state = createState(stateSeed);
   const listeners = new Set<() => void>();
   let notifyScheduled = false;
 
@@ -55,7 +64,7 @@ export function createDaemonTranscriptStore(
     dispatch(event: DaemonUiEvent | DaemonUiEvent[]) {
       const events = Array.isArray(event) ? event : [event];
       if (events.length === 0) return;
-      state = reduceDaemonTranscriptEvents(state, events);
+      state = reduceDaemonTranscriptEvents(state, events, reducerOptions);
       scheduleNotify();
     },
     appendLocalUserMessage(
@@ -74,12 +83,14 @@ export function createDaemonTranscriptStore(
         images,
         meta,
         files,
+        ...reducerOptions,
       });
       scheduleNotify();
     },
     reset(nextSeed: Partial<DaemonTranscriptState> = {}) {
       state = createState({
         maxBlocks: nextSeed.maxBlocks ?? state.maxBlocks,
+        maxRetainedBytes: nextSeed.maxRetainedBytes ?? state.maxRetainedBytes,
         retainSubagentBlocks:
           nextSeed.retainSubagentBlocks ?? state.retainSubagentBlocks,
         ...nextSeed,
@@ -147,10 +158,19 @@ function createState(
   return {
     ...createDaemonTranscriptState({
       maxBlocks: seed.maxBlocks,
+      maxRetainedBytes: seed.maxRetainedBytes,
       now: seed.now,
     }),
     ...seed,
     blocks,
+    // Seeded blocks (e.g. a replay snapshot handed to `reset`) must count
+    // toward the retention byte budget from the start.
+    retainedBytes:
+      seed.retainedBytes ??
+      blocks.reduce(
+        (total, block) => total + estimateDaemonTranscriptBlockBytes(block),
+        0,
+      ),
     blockIndexById: rebuildDaemonTranscriptBlockIndex(blocks),
     toolBlockByCallId: createNullIndex(seed.toolBlockByCallId),
     trimmedToolNotificationByCallId: createNullIndex(

packages/sdk-typescript/src/daemon/ui/toolPreview.ts

@@ -10,6 +10,7 @@ import type {
   DaemonTranscriptQuestionOption,
 } from './types.js';
 import {
+  capDetails,
   getFirstString,
   isRecord,
   isSensitiveKey,
@@ -338,7 +339,9 @@ function collectPreviewRows(
     if (isRecord(value)) continue;
     rows.push({
       label: key,
-      value: isSensitiveKey(key) ? '[redacted]' : stringifyRedactedJson(value),
+      value: isSensitiveKey(key)
+        ? '[redacted]'
+        : capDetails(stringifyRedactedJson(value)),
     });
   }
   return rows;