a turn this tab did not start is still a turn in progress

"Turn finished · no closing message" kept appearing over an agent that was
plainly still working, with output resuming a moment later.

isGenerating was set in exactly three places: sendPrompt, and the two reconnect
handshakes. So it answered "am I waiting for a reply I asked for", never "is
this conversation working". Every other way a turn begins left it false — a
commander waking on its own schedule, a queued prompt the server delivered,
another tab driving the same session, or a turn that started before this tab
was looking. The events still render, but buildRows reads isGenerating to
decide whether the last turn is finished, so a live turn was `complete` and the
moment it sat on a completed tool call with nothing said after it, the banner
fired. Same gap left the composer enabled mid-turn, and a message typed then
was not marked injected — which splits the live turn and prints the banner a
second way, the exact failure injected exists to prevent.

session:claude now sets it: the harness's own turn-start signal, and the only
one that arrives before any work does. tool:start sets it too, because
session:claude is not durable and a socket connecting mid-turn never receives
one, while a tool cannot start outside a turn.

Two candidates were measured rather than argued. A genuinely silent turn ending
earns the banner honestly, but 667 of 673 recorded turns end with
assistant:text immediately before result, so that is ~1% and cannot be it. And
a stale sync:live is real but rare: correlating every attach in the officer log
against the agent's own later output, 15 of 549 "not generating" attaches were
contradicted and one provably so. That residue is left alone — the tool:start
fallback now corrects it on the next event — and noted on the refresh card,
which is the same seam.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Officer-Session: f7a62308-0977-4cf4-aa29-c020853fd420

src/workspaces/officerdev/src/hooks/useChat.ts

@@ -409,10 +409,26 @@ export function useChat(initialSessionId?: string, initialModel?: string | null,
         break;
 
       case 'session:claude':
-        // The turn has only just begun and the conversation is already addressable. Everything that makes
-        // a refresh survivable hangs off this: the URL is what the reattach handshake sends, so writing it
-        // here rather than at `result` is the difference between "refresh mid-turn and lose the turn" and
-        // "refresh mid-turn and watch it carry on".
+        /*
+          A turn is starting, and THIS TAB MAY NOT BE THE ONE THAT STARTED IT.
+
+          `isGenerating` used to be set in exactly three places — `sendPrompt`, and the two reconnect
+          handshakes — so it answered "am I waiting for a reply I asked for", not "is this conversation
+          working". Every other way a turn begins left it false: a commander waking on its own schedule, a
+          queued prompt the server delivered, another tab or another device driving the same session.
+
+          The tab still rendered the work, because the events arrive either way. But `buildRows` reads
+          `isGenerating` to decide whether the last turn is finished, so with it false a live turn is
+          `complete`, and the moment it sat on a completed tool call with nothing said after it the reader
+          got "Turn finished · no closing message" — over an agent that carried on a second later. It also
+          left the composer enabled mid-turn, and a message typed then was not marked `injected`, which
+          splits the live turn: the precise failure `injected` exists to prevent (see types.ts).
+
+          Marked here rather than on the first tool call because this is the harness's own turn-start
+          signal, and it is the only one that arrives before any work does.
+        */
+        setIsGenerating(true);
+        setHasStarted(true);
         claudeSessionIdRef.current = msg.claudeSessionId;
         setClaudeSessionId(msg.claudeSessionId);
         if (replaceUrl) writePermalink(msg.claudeSessionId);
@@ -449,6 +465,9 @@ export function useChat(initialSessionId?: string, initialModel?: string | null,
       }
 
       case 'tool:start': {
+        // Belt and braces for a turn whose `session:claude` this tab missed — an event that is NOT durable,
+        // so a socket that connects mid-turn never receives one. A tool cannot start outside a turn.
+        setIsGenerating(true);
         toolCallsInTurnRef.current = true;
         const call: ChatMessage = {
           role: 'tool',