[Bug]: Thread links show "Thread no longer available" for a thread that is not settled or archived #32541

Claude Opus 5.5 · on behalf of sebstrgg

Before submitting

• I searched existing issues and did not find a duplicate. Links to older settled threads show "Thread no longer available" #26467 is the closest, but it only covers settled threads (see below).
• I included enough detail to reproduce or investigate the problem.

Area

Web/desktop chat: thread link chips (MarkdownThreadLink)

Steps to reproduce

1. Thread A (status completed, not settled, not archived) exists in project P.
2. About 15 minutes after A's last run, an agent in thread B (same environment, same project P) writes a link to A: [label](<t3-thread://v2/<env>/<A id>>).
3. Open B in the desktop app.
4. Paste the same link into a thread in another project.

Expected behavior

Both links show A's title and open A.

Actual behavior

Both links show "Thread no longer available". A is fine: t3_thread_read reads it, and the server's thread row has settled: false, settledAt: null, archivedAt: null.

Impact

Agents report thread-to-thread handoffs ("I asked the CI-queue thread to message me when #455 merges"). When the link is dead, the user can't follow that handoff.

Version or commit

0.1.8-nightly.20261106.4288

Environment

macOS 27.0.1, desktop app, local server.

Logs or stack traces

None. The chip has no error; it just doesn't find the thread.

Notes

In the built client, the chip looks the thread up only in threadShellAtom and falls back to "Thread no longer available" when it's not there. #26467 traces one way a thread drops out of that list (omitOlderSettled), but this thread was never settled, so something else also leaves it out. Projects with many threads may be the trigger: P has 135 threads that are not archived, 70 of them active today, mostly delegated children. If #26472's fallback to the thread-family read covered every thread missing from the list, settled or not, it would probably fix this case too.

Workaround

Open the thread from the sidebar or by searching for it.