fix: expose summaryStored in session status to detect silent summary loss (#1633)

Stop hook polled queueLength===0 as a proxy for summary success, but the queue
empties regardless of whether the LLM produced valid <summary> tags. Added
lastSummaryStored tracking on ActiveSession, surfaced via the /api/sessions/status
endpoint, and emit a logger.warn in the Stop hook when summaryStored===false.

Generated by Claude Code
Vibe coded by ousamabenyounes

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

src/cli/handlers/summarize.ts

@@ -87,6 +87,7 @@ export const summarizeHandler: EventHandler = {
     //    This keeps the Stop hook alive (120s timeout) so the SDK agent
     //    can finish processing the summary before SessionEnd kills the session.
     const waitStart = Date.now();
+    let summaryStored: boolean | null = null;
     while ((Date.now() - waitStart) < MAX_WAIT_FOR_SUMMARY_MS) {
       await new Promise(resolve => setTimeout(resolve, POLL_INTERVAL_MS));
       try {
@@ -94,11 +95,21 @@ export const summarizeHandler: EventHandler = {
           timeoutMs: 5000
         });
         if (statusResponse.ok) {
-          const status = await statusResponse.json() as { queueLength?: number };
+          const status = await statusResponse.json() as { queueLength?: number; summaryStored?: boolean | null };
           if ((status.queueLength ?? 0) === 0) {
+            summaryStored = status.summaryStored ?? null;
             logger.info('HOOK', 'Summary processing complete', {
-              waitedMs: Date.now() - waitStart
+              waitedMs: Date.now() - waitStart,
+              summaryStored
             });
+            // Warn when the agent processed a summarize request but produced no storable summary.
+            // This is the silent-failure path described in #1633: queue empties but no summary record exists.
+            if (summaryStored === false) {
+              logger.warn('HOOK', 'Summary was not stored: LLM response likely lacked valid <summary> tags (#1633)', {
+                sessionId,
+                waitedMs: Date.now() - waitStart
+              });
+            }
             break;
           }
         }

src/services/worker-types.ts

@@ -43,6 +43,9 @@ export interface ActiveSession {
   processingMessageIds: number[];
   // Tier routing: model override per session based on queue complexity
   modelOverride?: string;
+  // Track whether the most recent storage operation persisted a summary record.
+  // Used by the status endpoint so the Stop hook can detect silent summary loss (#1633).
+  lastSummaryStored?: boolean;
 }
 
 export interface PendingMessage {

src/services/worker/agents/ResponseProcessor.ts

@@ -126,6 +126,10 @@ export async function processAgentResponse(
     memorySessionId: session.memorySessionId
   });
 
+  // Track whether a summary record was stored so the status endpoint can expose this
+  // to the Stop hook for silent-summary-loss detection (#1633)
+  session.lastSummaryStored = result.summaryId !== null;
+
   // CLAIM-CONFIRM: Now that storage succeeded, confirm all processing messages (delete from queue)
   // This is the critical step that prevents message loss on generator crash
   const pendingStore = sessionManager.getPendingMessageStore();

src/services/worker/http/routes/SessionRoutes.ts

@@ -672,6 +672,9 @@ export class SessionRoutes extends BaseRouteHandler {
       status: 'active',
       sessionDbId,
       queueLength,
+      // Expose whether the last storage operation included a summary record.
+      // The Stop hook uses this to detect silent summary loss when the queue empties (#1633).
+      summaryStored: session.lastSummaryStored ?? null,
       uptime: Date.now() - session.startTime
     });
   });