v2: fix agent-runner lifecycle and session DB reliability

- Use DELETE journal mode for session DBs instead of WAL. WAL doesn't
  sync reliably across Docker volume mounts (VirtioFS), causing dropped
  writes and duplicate deliveries.
- Add 20s idle detection to end the query stream. The concurrent poll
  tracks SDK activity via a new 'activity' provider event. When no SDK
  events arrive for 20s and no messages are pending, the stream ends
  and the poll loop continues.
- Add touchProcessing heartbeat so the host can distinguish active
  agents from idle ones by checking status_changed recency.
- Catch query errors in the poll loop and write error responses to
  messages_out instead of crashing the process.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

container/agent-runner/src/db/connection.ts

@@ -7,7 +7,7 @@ let _db: Database.Database | null = null;
 export function getSessionDb(): Database.Database {
   if (!_db) {
     _db = new Database(process.env.SESSION_DB_PATH || SESSION_DB_PATH);
-    _db.pragma('journal_mode = WAL');
+    _db.pragma('journal_mode = DELETE');
     _db.pragma('foreign_keys = ON');
   }
   return _db;

container/agent-runner/src/db/messages-in.ts

@@ -47,6 +47,14 @@ export function markCompleted(ids: string[]): void {
   })();
 }
 
+/** Update status_changed on processing messages (heartbeat for host idle detection). */
+export function touchProcessing(ids: string[]): void {
+  if (ids.length === 0) return;
+  const db = getSessionDb();
+  const stmt = db.prepare("UPDATE messages_in SET status_changed = datetime('now') WHERE id = ? AND status = 'processing'");
+  for (const id of ids) stmt.run(id);
+}
+
 /** Mark a single message as failed. */
 export function markFailed(id: string): void {
   getSessionDb().prepare("UPDATE messages_in SET status = 'failed', status_changed = datetime('now') WHERE id = ?").run(id);

container/agent-runner/src/poll-loop.test.ts

@@ -120,10 +120,11 @@ describe('mock provider', () => {
       events.push(event);
     }
 
-    expect(events.length).toBeGreaterThanOrEqual(2);
-    expect(events[0].type).toBe('init');
-    expect(events[1].type).toBe('result');
-    expect((events[1] as { text: string }).text).toBe('Echo: Hello');
+    const typed = events.filter((e) => e.type !== 'activity');
+    expect(typed.length).toBeGreaterThanOrEqual(2);
+    expect(typed[0].type).toBe('init');
+    expect(typed[1].type).toBe('result');
+    expect((typed[1] as { text: string }).text).toBe('Echo: Hello');
   });
 
   it('should handle push() during active query', async () => {

container/agent-runner/src/poll-loop.ts

@@ -1,10 +1,11 @@
-import { getPendingMessages, markProcessing, markCompleted } from './db/messages-in.js';
+import { getPendingMessages, markProcessing, markCompleted, touchProcessing } from './db/messages-in.js';
 import { writeMessageOut } from './db/messages-out.js';
 import { formatMessages, extractRouting, type RoutingContext } from './formatter.js';
 import type { AgentProvider, AgentQuery, McpServerConfig, ProviderEvent } from './providers/types.js';
 
 const POLL_INTERVAL_MS = 1000;
 const ACTIVE_POLL_INTERVAL_MS = 500;
+const IDLE_END_MS = 20_000; // End stream after 20s with no SDK events
 
 function log(msg: string): void {
   console.error(`[poll-loop] ${msg}`);
@@ -68,10 +69,22 @@ export async function runPollLoop(config: PollLoopConfig): Promise<void> {
     });
 
     // Process the query while concurrently polling for new messages
-    const result = await processQuery(query, routing, config);
-
-    if (result.sessionId) sessionId = result.sessionId;
-    if (result.resumeAt) resumeAt = result.resumeAt;
+    try {
+      const result = await processQuery(query, routing, config, ids);
+      if (result.sessionId) sessionId = result.sessionId;
+      if (result.resumeAt) resumeAt = result.resumeAt;
+    } catch (err) {
+      log(`Query error: ${err instanceof Error ? err.message : String(err)}`);
+      // Write error response so the user knows something went wrong
+      writeMessageOut({
+        id: generateId(),
+        kind: 'chat',
+        platform_id: routing.platformId,
+        channel_type: routing.channelType,
+        thread_id: routing.threadId,
+        content: JSON.stringify({ text: `Error: ${err instanceof Error ? err.message : String(err)}` }),
+      });
+    }
 
     markCompleted(ids);
     log(`Completed ${ids.length} message(s)`);
@@ -83,34 +96,43 @@ interface QueryResult {
   resumeAt?: string;
 }
 
-async function processQuery(query: AgentQuery, routing: RoutingContext, config: PollLoopConfig): Promise<QueryResult> {
+async function processQuery(query: AgentQuery, routing: RoutingContext, config: PollLoopConfig, processingIds: string[]): Promise<QueryResult> {
   let querySessionId: string | undefined;
   let done = false;
+  let lastEventTime = Date.now();
 
-  // Concurrent polling: push new messages into the active query
+  // Concurrent polling: push follow-ups, checkpoint WAL, detect idle
   const pollHandle = setInterval(() => {
     if (done) return;
+
     const newMessages = getPendingMessages();
-    if (newMessages.length === 0) return;
+    if (newMessages.length > 0) {
+      const newIds = newMessages.map((m) => m.id);
+      markProcessing(newIds);
 
-    const newIds = newMessages.map((m) => m.id);
-    markProcessing(newIds);
+      const prompt = formatMessages(newMessages);
+      log(`Pushing ${newMessages.length} follow-up message(s) into active query`);
+      query.push(prompt);
 
-    const prompt = formatMessages(newMessages);
-    log(`Pushing ${newMessages.length} follow-up message(s) into active query`);
-    query.push(prompt);
+      const newRouting = extractRouting(newMessages);
+      setRoutingEnv(newRouting, config.env);
 
-    // Update routing env for MCP tools with latest message context
-    const newRouting = extractRouting(newMessages);
-    setRoutingEnv(newRouting, config.env);
+      markCompleted(newIds);
+      lastEventTime = Date.now(); // new input counts as activity
+    }
 
-    // Mark these completed immediately (they've been pushed to the provider)
-    markCompleted(newIds);
+    // End stream when agent is idle: no SDK events and no pending messages
+    if (Date.now() - lastEventTime > IDLE_END_MS) {
+      log(`No SDK events for ${IDLE_END_MS / 1000}s, ending query`);
+      query.end();
+    }
   }, ACTIVE_POLL_INTERVAL_MS);
 
   try {
     for await (const event of query.events) {
+      lastEventTime = Date.now();
       handleEvent(event, routing);
+      touchProcessing(processingIds);
 
       if (event.type === 'init') {
         querySessionId = event.sessionId;

container/agent-runner/src/providers/claude.ts

@@ -200,6 +200,9 @@ export class ClaudeProvider implements AgentProvider {
         if (aborted) return;
         messageCount++;
 
+        // Yield activity for every SDK event so the poll loop knows the agent is working
+        yield { type: 'activity' };
+
         if (message.type === 'system' && message.subtype === 'init') {
           yield { type: 'init', sessionId: message.session_id };
         } else if (message.type === 'result') {
@@ -213,7 +216,6 @@ export class ClaudeProvider implements AgentProvider {
           const tn = message as { summary?: string };
           yield { type: 'progress', message: tn.summary || 'Task notification' };
         }
-        // All other message types are logged but not emitted
       }
       log(`Query completed after ${messageCount} SDK messages`);
     }

container/agent-runner/src/providers/mock.ts

@@ -20,9 +20,11 @@ export class MockProvider implements AgentProvider {
 
     const events: AsyncIterable<ProviderEvent> = {
       async *[Symbol.asyncIterator]() {
+        yield { type: 'activity' };
         yield { type: 'init', sessionId: `mock-session-${Date.now()}` };
 
         // Process initial prompt
+        yield { type: 'activity' };
         yield { type: 'result', text: responseFactory(input.prompt) };
 
         // Process any pushed follow-ups

container/agent-runner/src/providers/types.ts

@@ -53,4 +53,5 @@ export type ProviderEvent =
   | { type: 'init'; sessionId: string }
   | { type: 'result'; text: string | null }
   | { type: 'error'; message: string; retryable: boolean; classification?: string }
-  | { type: 'progress'; message: string };
+  | { type: 'progress'; message: string }
+  | { type: 'activity' };

src/session-manager.ts

@@ -80,7 +80,7 @@ export function initSessionFolder(agentGroupId: string, sessionId: string): void
   const dbPath = sessionDbPath(agentGroupId, sessionId);
   if (!fs.existsSync(dbPath)) {
     const db = new Database(dbPath);
-    db.pragma('journal_mode = WAL');
+    db.pragma('journal_mode = DELETE');
     db.exec(SESSION_SCHEMA);
     db.close();
     log.debug('Session DB created', { dbPath });
@@ -105,7 +105,7 @@ export function writeSessionMessage(
 ): void {
   const dbPath = sessionDbPath(agentGroupId, sessionId);
   const db = new Database(dbPath);
-  db.pragma('journal_mode = WAL');
+  db.pragma('journal_mode = DELETE');
 
   try {
     db.prepare(
@@ -134,7 +134,7 @@ export function writeSessionMessage(
 export function openSessionDb(agentGroupId: string, sessionId: string): Database.Database {
   const dbPath = sessionDbPath(agentGroupId, sessionId);
   const db = new Database(dbPath);
-  db.pragma('journal_mode = WAL');
+  db.pragma('journal_mode = DELETE');
   return db;
 }