end a turn whose agent has gone

restarting officer-agent takes every persistent session with it and nothing
downstream notices: the browser's socket is healthy, officer's subscription is
a bus filter, and there is simply never another event. the spinner ran forever
and a refresh didn't help, because the transcript has no ending to read.

keyed off the agent *registering*, not disconnecting — a disconnect fires on
every `pm2 restart officer`, when the turn is fine. a registration socket dies
with its process, so an agent appearing on it is a new one. covers the sitting
tab; the reconnect path covers the rest, with the client now sending its belief
that a turn is in flight and officer checking it against the agent over a new
claude:is-generating. the check fails toward alive.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/servers/api/chat/types.ts

@@ -87,6 +87,11 @@ export type ClientMessage =
       // client is the only party that still remembers them — officer's copy died with the process.
       model?: string;
       cwd?: string;
+      /**
+       * The client still shows a turn in flight. Officer cannot know this on its own after a restart, and
+       * it is the one claim worth checking against the agent — see `endTurnIfAgentIsGone`.
+       */
+      generating?: boolean;
     };
 
 // The `Task` tool's id, when this piece of output came from a subagent rather than the agent you are

src/servers/api/chat/websocket.ts

@@ -8,7 +8,7 @@ import { ensureGeneralChatSessionsCwd } from './claude-sessions';
 import * as sidecar from '@@/sidecar-registry';
 import { join } from 'path';
 import { getOwnerHomeDir, getEmailAccountsDir } from '../../../servers/data-path';
-import { getUserSettings, getEmailAccounts, getChatEventsSince } from 'officerdb';
+import { getUserSettings, getEmailAccounts, getChatEventsSince, appendChatEvent } from 'officerdb';
 import { mkdirSync } from 'node:fs';
 import { logger } from './logger';
 
@@ -579,11 +579,12 @@ function adoptOrphanedSession(ws: ServerWebSocket<WSData>, sessionId: string, mo
 // task:notification. attachWs cancels the pending idle-GC.
 async function handleResumeCursor(
   ws: ServerWebSocket<WSData>,
-  msg: { sessionId: string; cursor: number; model?: string; cwd?: string },
+  msg: { sessionId: string; cursor: number; model?: string; cwd?: string; generating?: boolean },
 ): Promise<void> {
   const { sessionId, cursor } = msg;
+  const model = msg.model || DEFAULT_MODEL;
   if (!sessionManager.getSession(sessionId)) {
-    adoptOrphanedSession(ws, sessionId, msg.model || DEFAULT_MODEL, msg.cwd ?? '');
+    adoptOrphanedSession(ws, sessionId, model, msg.cwd ?? '');
   }
   sessionManager.attachWs(sessionId, ws);
   wsToSessionMap.set(ws as any, sessionId);
@@ -595,8 +596,58 @@ async function handleResumeCursor(
   } catch (err) {
     logger.error('Failed to replay chat events on resume-cursor', { sessionId, error: String(err) });
   }
+  if (msg.generating) await endTurnIfAgentIsGone(ws, sessionId, model);
 }
 
+/**
+ * The client came back still believing a turn is running. Check whether it is, and if it isn't, say so.
+ *
+ * A restart of the agent sidecar takes its persistent sessions with it, and nothing downstream notices:
+ * the turn simply stops emitting. The browser's socket is fine, the conversation looks alive, and the
+ * spinner runs forever — a refresh doesn't help either, because there is no ending in the transcript to
+ * read. This is the one moment we can catch it, so the answer is written durably: a reload after this
+ * shows the same explanation rather than a conversation that trails off mid-tool-call.
+ *
+ * Only the claude harness is asked. OpenCode runs a turn per invocation and has no equivalent question,
+ * so its sessions are left alone rather than guessed at.
+ */
+async function endTurnIfAgentIsGone(
+  ws: ServerWebSocket<WSData> | null,
+  sessionId: string,
+  model: string,
+): Promise<void> {
+  if (!isClaudeModel(model)) return;
+  if (await sidecar.isClaudeGenerating(sessionId)) return;
+
+  const session = sessionManager.getSession(sessionId);
+  if (session) session.isGenerating = false;
+
+  const event: ServerMessage = {
+    type: 'error',
+    message: 'The agent restarted while this turn was running, so it was cut off. The conversation is intact.',
+  };
+  try {
+    const seq = await appendChatEvent(sessionId, event);
+    sendToClient(ws, event, seq);
+  } catch (err) {
+    // Still tell this client — an un-replayable explanation beats a spinner that never stops.
+    logger.error('Failed to persist cut-off notice', { sessionId, error: String(err) });
+    sendToClient(ws, event);
+  }
+  logger.info('Ended a turn whose agent had gone', { sessionId });
+}
+
+// The other half of the same problem: the agent restarts while the browser sits there with a healthy
+// socket, so nothing ever reconnects and nothing ever asks. A fresh agent process means every turn we
+// still believe is running belongs to a process that no longer exists. On a fresh officer this loop is
+// empty — it has no sessions yet — which is exactly right, because that case is the reconnect's to catch.
+sidecar.onClaudeSidecarStarted(() => {
+  for (const session of sessionManager.getAllSessions()) {
+    if (!session.isGenerating) continue;
+    void endTurnIfAgentIsGone(session.ws as ServerWebSocket<WSData> | null, session.sessionId, session.model);
+  }
+});
+
 export const chatWebsocket = {
   open,
   message,

src/servers/sidecar-registry.ts

@@ -65,9 +65,31 @@ export function registerSidecar(ws: ServerWebSocket<any>, registration: SidecarR
   console.log(
     `[registry] registered sidecar "${registration.name}" (id=${id}, capabilities=[${registration.capabilities.join(', ')}])`,
   );
+
+  // A registration socket lives and dies with its process, so an agent showing up here is an agent that
+  // has just started — and whatever it was running before is gone. Announced rather than inferred from
+  // the *disconnect*, which is the wrong signal entirely: every `pm2 restart officer` drops these sockets
+  // while the sidecars, and their turns, carry on perfectly well.
+  if (registration.capabilities.includes('claude')) {
+    for (const handler of claudeRestartHandlers) {
+      try {
+        handler();
+      } catch (err) {
+        console.error('[registry] claude-restart handler failed', err);
+      }
+    }
+  }
   return id;
 }
 
+const claudeRestartHandlers = new Set<() => void>();
+
+/** Notified when the agent sidecar registers — i.e. when a new agent process has come up. */
+export function onClaudeSidecarStarted(handler: () => void): () => void {
+  claudeRestartHandlers.add(handler);
+  return () => claudeRestartHandlers.delete(handler);
+}
+
 export function unregisterSidecar(id: string): void {
   const sc = sidecars.get(id);
   if (!sc) return;
@@ -273,6 +295,29 @@ export function interruptClaude(sessionKey: string): void {
   sendFire('claude', { type: 'claude:interrupt', id: nextId(), sessionKey });
 }
 
+/**
+ * Is the agent still running a turn for this session?
+ *
+ * Asked of the sidecar because it is the only party that can answer: officer's own memory of a turn dies
+ * with `pm2 restart officer` while the turn itself carries on, so "we don't remember it" is not evidence
+ * of anything. Used on reconnect to tell those two apart — a turn that outlived a restart from one whose
+ * process is gone and is never going to produce another token.
+ *
+ * Fails *toward alive*: no answer means we don't know, and wrongly telling someone their turn died while
+ * it is still typing is worse than leaving a spinner up a little longer. Only a registered agent that
+ * says "no", or no agent at all, counts as dead.
+ */
+export async function isClaudeGenerating(sessionKey: string): Promise<boolean> {
+  const sc = findSidecarByCapability('claude');
+  if (!sc) return false;
+  try {
+    const res = await sendCommandToSidecar(sc, { type: 'claude:is-generating', id: nextId(), sessionKey });
+    return res.type === 'claude:generating' ? res.generating : true;
+  } catch {
+    return true;
+  }
+}
+
 export function clearClaudeSession(sessionKey: string): void {
   sendFire('claude', { type: 'claude:clear-session', id: nextId(), sessionKey });
 }

src/servers/sidecar/claude/claude-manager.ts

@@ -379,3 +379,15 @@ export function clearSession(sessionKey: string): void {
 export function getActiveSessionKeys(): string[] {
   return Array.from(sessions.keys());
 }
+
+/**
+ * Is a turn actually in flight for this session, right now, in this process?
+ *
+ * This is the ground truth a reconnecting browser has no way to work out for itself. Officer's own view
+ * dies with `pm2 restart officer` while the turn keeps running here, so "officer doesn't remember" means
+ * nothing — and if *this* process was the one that restarted, the session is simply absent and the turn
+ * it was running is gone, however alive the client still believes it to be.
+ */
+export function isSessionGenerating(sessionKey: string): boolean {
+  return sessions.get(sessionKey)?.isGenerating ?? false;
+}

src/servers/sidecar/claude/user-instance.ts

@@ -190,6 +190,10 @@ async function handleCommand(cmd: SidecarCommand, reply: ReplyFn) {
       reply({ type: 'claude:interrupted', id: cmd.id });
       break;
 
+    case 'claude:is-generating':
+      reply({ type: 'claude:generating', id: cmd.id, generating: claudeManager.isSessionGenerating(cmd.sessionKey) });
+      break;
+
     case 'claude:clear-session':
       claudeManager.clearSession(cmd.sessionKey);
       sessionLog.drop(cmd.sessionKey);

src/servers/sidecar/protocol.ts

@@ -17,6 +17,9 @@ export type SidecarCommand =
   | { type: 'claude:kill'; id: string; sessionKey: string }
   | { type: 'claude:interrupt'; id: string; sessionKey: string }
   | { type: 'claude:clear-session'; id: string; sessionKey: string }
+  // Is a turn still running for this session? Only the process that owns the session can say, which is
+  // exactly why it is asked over the wire — see `isClaudeGenerating` in sidecar-registry.
+  | { type: 'claude:is-generating'; id: string; sessionKey: string }
   // OpenCode — drive a turn via `opencode run … --format json` (tools re-anchored to cwd via --dir)
   | { type: 'opencode:run-streaming'; id: string; params: OpenCodeRunParams }
   | { type: 'opencode:kill'; id: string; sessionKey: string }
@@ -43,6 +46,7 @@ export type SidecarEvent =
   | { type: 'claude:killed'; id: string }
   | { type: 'claude:interrupted'; id: string }
   | { type: 'claude:session-cleared'; id: string }
+  | { type: 'claude:generating'; id: string; generating: boolean }
   // VNC
   | { type: 'vnc:started'; id: string; port: number; display: number }
   | { type: 'vnc:password'; id: string; password: string }