[BUG] Cowork Dispatch completes tasks successfully but renders no response on desktop or mobile

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?

Dispatch sessions spawn, execute child tasks, and complete with isError=false, but no response text is ever rendered in the UI on either the desktop Cowork window or the Claude mobile app.
The user sees their query appear, a brief thinking/processing indicator, and then nothing. No error, no empty bubble, no output at all.
Regular Cowork sessions on the same machine work perfectly. The issue is specific to Dispatch.

What Should Happen?

Dispatch should render Claude's response in the conversation thread on both desktop and mobile surfaces after the task completes.

Error Messages/Logs

No errors are logged. That is the problem. Tasks complete silently with success status.
cowork_vm_node.log pattern (repeats on every Dispatch message):
2026-03-28 11:11:08 [info] [Spawn:vm] id=edbbd817 Spawn succeeded in 48ms
2026-03-28 11:11:56 [info] [CoworkVMProcess:edbbd817] kill called with signal: SIGTERM
2026-03-28 11:11:56 [info] [Process:edbbd817] Exited, code=0, signal=null, duration=48062ms, oom=false
main.log confirms tasks complete successfully:
2026-03-28 11:11:08 [info] [DispatchMcp] Building start_code_task schema with 4 models: claude-opus-4-6, claude-opus-4-6[1m], claude-sonnet-4-6, claude-haiku-4-5-20251001
2026-03-28 11:11:18 [info] [DispatchMcp] Spawned child local_ab714748 ("Browse Downloads folder") for parent local_ditto_cc82c409
2026-03-28 11:11:19 [info] [LocalAgentModeSessionManager] Dispatch child session: disabling renderer-dependent tools
2026-03-28 11:11:56 [info] [sessions-bridge] Query completed for session cse_01KmUUPtzEJRuGBvYQet5SUr (pendingTurns=0, isError=false)
Keepalive timeout observed on one session:
2026-03-28 10:36:37 [warn] [Keepalive] Ping failed: Keep-alive ping timed out
2026-03-28 10:36:42 [info] [CoworkVMProcess] kill called with signal: SIGTERM
Tool configuration conflict in spawn args:
mcp__cowork__present_files appears in both --allowedTools and --disallowedTools.

Tool configuration conflict in spawn args:
mcp__cowork__present_files appears in both --allowedTools and --disallowedTools.

Steps to Reproduce

1. Open Claude Desktop (latest), go to Cowork, open Dispatch
2. Pair with Claude mobile app via QR code
3. Send any message from the phone (tested with "say hello", file browsing tasks, and other simple prompts)
4. Observe on desktop: query appears in Cowork window, thinking indicator runs briefly, then stops with no response
5. Observe on mobile: same behaviour, no response rendered
6. Check logs: main.log shows Query completed (pendingTurns=0, isError=false)
7. Open a regular Cowork session on the same machine, send the same prompt: works fine

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

1.0.61 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

1. Updated Claude Desktop and Claude iOS to latest versions
2. Removed all marketplace plugins except cowork-plugin-management 0.2.2 (reduced from 4 plugin directories to 1)
3. Deleted and reinstalled Claude iOS app to force fresh pairing
4. Re-paired via QR code to get a new Dispatch thread (eliminated --resume flag)
5. Tested with trivially simple prompts requiring no tools
6. Confirmed regular Cowork works on the same machine with identical configuration
7. Verified VM boots cleanly, network connects, API is reachable

Key observations

• sessions-bridge reports Query completed (pendingTurns=0, isError=false) confirming the backend considers the task done. The bug is in surfacing results to the UI.
• Child sessions log Dispatch child session: disabling renderer-dependent tools which may be preventing output from reaching the renderer.
• mcp__cowork__present_files is in both --allowedTools and --disallowedTools in the spawn arguments, which is a contradiction.
• Dispatch parent sessions are SIGTERM'd after 6-48 seconds. They exit cleanly (code=0, no OOM). Regular Cowork child sessions on the same machine run for similar durations and render output successfully.
• The Dispatch seed message flow works (Writing 1 Dispatch seed message(s) + idle result for session) but subsequent query results do not render.