trigger-chat-transport-watch-mode.md

@trigger.dev/sdk	patch

Add watch option to TriggerChatTransport for read-only observation of an existing chat run.

When set to true, the transport keeps its internal ReadableStream open across trigger:turn-complete control chunks instead of closing it after each turn. This lets a single useChat / resumeStream subscription observe every turn of a long-lived agent run — useful for dashboard viewers or debug UIs that only want to watch an existing conversation as it unfolds, rather than drive it.

const transport = new TriggerChatTransport({
  task: "my-chat-task",
  accessToken: runScopedPat,
  watch: true,
  sessions: {
    [chatId]: { runId, publicAccessToken: runScopedPat },
  },
});

const { messages, resumeStream } = useChat({ id: chatId, transport });
useEffect(() => { resumeStream(); }, [resumeStream]);

Non-watch transports are unaffected — the default remains false and existing behavior (close on turn-complete so useChat can flip to "ready" between turns) is preserved for interactive playground-style flows.