[BUG] Cowork Dispatch start_code_task sessions never execute in Code tab (Windows)

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?

When Cowork Dispatch creates Code tab sessions via start_code_task, the sessions appear in the Code tab with the prompt visible, but Claude never begins executing. The session stays permanently idle.

Observed behavior:

• Dispatch calls start_code_task with a prompt and workspace path
• The session appears in the Code tab showing the user message/prompt
• Claude (the assistant) never responds — no output, no tool calls, no errors
• The "Reply..." input box is visible but typing into it is completely swallowed — text does not appear
• No workspace approval prompt is shown
• Session status alternates briefly between "running" and "idle" then stays idle permanently

Key finding: Starting a fresh Code tab session directly (not via Dispatch) with the same workspace works perfectly — Claude responds immediately and can execute commands. This confirms the Code tab itself is functional; the issue is specifically in the Dispatch-to-Code handoff.

Reproduction: 100% reproducible. Tested 10+ times across multiple Dispatch sessions in a single Cowork conversation. Restarting Claude Desktop did not resolve the issue.

Workaround: Start Code tab sessions manually and paste instructions from Dispatch, rather than using start_code_task.

What Should Happen?

When Dispatch calls start_code_task, the resulting Code tab session should begin executing immediately (or after workspace approval). Claude should process the prompt, run tools, and respond — exactly as it does when a session is started directly from the Code tab.

The Reply input box in Dispatch-created sessions should also accept typed input for follow-up messages.

Error Messages/Logs

No error messages displayed. The session simply never starts executing. No console errors, no approval dialogs, no visible failures. The Code tab shows the user prompt but Claude never generates a response.

Steps to Reproduce

1. Open Cowork mode in Claude Desktop (Windows 11)
2. In a Dispatch conversation, trigger a start_code_task call with any prompt and workspace C:\Users\<username>
3. Observe the Code tab — a new session appears with the prompt text visible
4. Claude never responds. The session shows as "idle" when checked via read_transcript
5. Try typing in the "Reply..." input box of the Dispatch-created session — text is swallowed, nothing appears
6. For comparison: click + to start a NEW Code tab session directly with the same workspace — this works immediately

Tested 10+ times across the same Cowork conversation. 100% reproducible. Restarting Claude Desktop did not fix it.

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude Desktop (Cowork mode) - exact version unknown, latest as of 2026-03-28

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

WSL (Windows Subsystem for Linux)

Additional Information

Environment details:

• Windows 11 with WSL (Ubuntu)
• Workspace path: C:\Users\Adam Rappaport
• Git repos accessed via WSL at \\wsl.localhost\Ubuntu\home\mentis
• Cowork Dispatch model: Opus 4.6 (1M context)
• Code tab model: Opus 4.6 (1M context)

Screenshot of dead Code tab session (created by Dispatch):
The session shows the user prompt but Claude never responds. The Reply input box accepts no typed input.

Additional observations:

• read_transcript from Dispatch shows the session as "idle" with only the user message, no assistant turns
• start_code_task returns successfully with a session_id and status "running", but it quickly drops to "idle"
• Multiple MCP servers connected (Gmail, Google Calendar, Vercel, Chrome automation, Google Drive, scheduled tasks)
• The same Dispatch conversation can successfully create non-code tasks via start_task that execute normally in the Cowork VM
• Only start_code_task (which targets the Code tab / host machine) is broken