[BUG] Desktop App (Cowork/local agent mode): AskUserQuestion never renders — hangs until session stop auto-denies (regression since 2026-06-03; re-filing locked #26940)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Since 2026-06-03 ~14:38 CEST, every AskUserQuestion call in a Cowork (local agent mode) session on Claude Desktop for macOS emits a tool permission request that never surfaces in the UI. The user sees only the frozen status line ("Using AskUserQuestion…"). The pending request is resolved as deny only when the session is stopped. Before the break: 15+ consecutive successful renders May 19 – Jun 3 12:15 across three rotated logs. After: zero.

This is the same defect as #26940 (filed 2026-02-19, closed by the stale-bot as not_planned with no maintainer response, then locked). The lock message asks for a new issue — this is that issue, with a regression timeline and elimination evidence the original lacked.

Success/failure record for every AskUserQuestion emission in retained logs (main.log, main1.log, main2.log):

| Period | Emitted | Answered | Hung until stop-deny |
|---|---|---|---|
| May 19 – Jun 3 12:15 | 13 | 12 | 1 (recovered on immediate retry) |
| Jun 3 14:38 → present | 2 | 0 | 2 |

Ruled out:

• Local app state. Survived multiple app restarts and a claude-code update + IndexedDB rebuild on 2026-06-04 09:48. The renderer's earlier Internal error opening backing store for indexedDB.open errors fired heavily during the working window and were absent after the rebuild while the failure persisted. Unrelated.
• The permission pipeline. Other tools ride the same channel and render fine throughout: 90+ Emitted tool permission request events for Desktop Commander, file tools, and Playwright in the same window, all approved interactively. AskUserQuestion is the only tool with Bridge resolving permission … behavior=deny events in three log files.
• Payload or skill context. The same skills issued the successful June 3 morning calls.
• Binary regression. The break occurred mid-instance. The app process that started 2026-06-02 20:34 on 1.9659.4 ran without restart through 2026-06-04 09:48 (Starting app events bracket the window). That same process answered AskUserQuestion at 12:15 on June 3 and hung at 14:38, same binary. The failure then persisted across the update to 1.10628.2 on June 4. A mid-instance onset that survives a version change points at remotely served frontend code or a server-evaluated flag, not the app binary. The window for the server-side change: 2026-06-03 12:15–14:38 CEST (10:15–12:38 UTC). (A renderer asset-reload storm of Failed to fetch errors from assets-proxy.anthropic.com is logged at 14:25, between last success and first failure.)

Related issues:

• #26940: identical symptom and environment, Feb 2026, closed-stale without response. This issue supersedes it.
• #64776: Desktop App AskUserQuestion widget defect filed 2026-06-02, one day before this regression window.
• #63806: question UI invisible behind the thinking spinner under extended thinking (CLI); possibly the same suppression mechanism.
• #29773: the CLI after-Skill variant, fixed 2026-04-18. This tool's rendering breaks per surface; the fixes land once an issue gets triaged.

What Should Happen?

The interactive question card (or at minimum a permission prompt) renders inline when AskUserQuestion is called, as it did on the same machine through 2026-06-03 12:15. The agent receives the user's selections.

Error Messages/Logs

Failure signature (the deny fires at the exact second of session stop, never from user action):

2026-06-03 14:38:43 [info] Emitted tool permission request 03675f88-7c00-4d30-888b-43679acace02 for AskUserQuestion in session local_7e5aa2aa-...
2026-06-04 06:42:43 [info] LocalAgentModeSessions.stop: sessionId=local_7e5aa2aa-...
2026-06-04 06:42:43 [info] Bridge resolving permission 03675f88-7c00-4d30-888b-43679acace02: behavior=deny (tool: AskUserQuestion)

2026-06-04 10:55:14 [info] Emitted tool permission request 22ea72c5-ac6f-4eb6-a9d1-9cb01aa9e1f2 for AskUserQuestion in session local_848a36e2-...
2026-06-04 10:56:46 [info] LocalAgentModeSessions.stop: sessionId=local_848a36e2-...
2026-06-04 10:56:46 [info] Bridge resolving permission 22ea72c5-ac6f-4eb6-a9d1-9cb01aa9e1f2: behavior=deny (tool: AskUserQuestion)

Working signature, last seen 2026-06-03 12:15 (same machine, same skills):

2026-06-03 12:15:19 [info] Emitted tool permission request 7834d736-... for AskUserQuestion in session local_5147e0a2-...
2026-06-03 12:15:28 [info] Received permission response for 7834d736-...: once (tool: AskUserQuestion)

Steps to Reproduce

1. Start a Cowork (local agent mode) session in Claude Desktop for macOS (observed on app 1.9659.4 and 1.10628.2, claude-code 2.1.161, claude-opus-4-8 with extended thinking enabled).
2. Give a task that leads Claude to call AskUserQuestion (any skill that collects structured input, or ask it to use the tool directly).
3. Observe: the status line shows the tool call, but no question card or permission prompt ever appears.
4. Stop the session. ~/Library/Logs/Claude/main.log logs Bridge resolving permission ...: behavior=deny (tool: AskUserQuestion) at the stop timestamp.

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Desktop app 1.9659.4 through 2026-06-03 12:15 CEST (break was mid-instance on the same version; server-side change suspected)

Claude Code Version

2.1.161 (Claude Code) — bundled in Claude Desktop 1.10628.2, Cowork local agent mode

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Other

Additional Information

Impact: blocks every interactive question flow in Cowork — skills that gate on user confirmation stall silently. The stop-deny workaround carries its own hazard: cancelling a pending tool call during extended thinking can poison the session with unrecoverable 400 thinking blocks cannot be modified errors (#63143, #63231).

Environment detail: model claude-opus-4-8, extended thinking (maxThinkingTokens 31999); Cowork local agent mode sessions. The Terminal/Shell field below is N/A — this is the desktop app UI, not a terminal session.

Happy to provide fuller sanitized log excerpts or test a diagnostic build.