Dispatch foreground chat shows no replies in Cowork mode while background session works

Summary

In Claude Desktop's Cowork/Dispatch mode, the foreground Dispatch chat UI shows no replies, while the background task session (the "Claude thinks here" workspace) continues to work normally and displays Claude's responses correctly.

The likely cause is that the SendUserMessage tool is not being injected correctly into the background session, so replies never get pushed back to the Dispatch foreground UI.

Symptoms

• In Cowork mode, the Dispatch foreground chat receives no visible reply.
• The background session still works normally.
• Claude replies are visible inside the background session.
• Claude can still execute actions successfully.
• Restarting Claude Desktop does not resolve the issue.

Likely cause

SendUserMessage is not correctly injected / available in the background session, so the background session can think, act, and respond internally, but cannot deliver those replies back to the Dispatch foreground UI.

Reproduction steps

1. Use Claude Desktop in Cowork / Dispatch mode.
2. Start a task in Dispatch.
3. After switching networks, observe that the issue begins to occur.
4. Claude continues to operate normally in the background session.
5. The Dispatch foreground chat shows no reply.
6. Restart Claude Desktop.
7. The issue still persists.

Actual result

• No reply appears in the Dispatch foreground chat UI.
• Replies remain visible only in the background session.

Expected result

• Replies generated in the background session should be delivered and displayed in the Dispatch foreground chat UI.

Japanese summary

Claude Desktop の Cowork / Dispatch モードで、Dispatch 前面チャット画面に返信が表示されません。一方で、バックグラウンドセッション（「Claude が思考を行う場所」）では Claude の返信が正常に表示され、動作実行も成功します。

原因としては、SendUserMessage ツールがバックグラウンドセッションに正しく注入されておらず、そのため返信を Dispatch 前面 UI に戻せていない可能性が高いです。

再現条件としては、ネットワーク切替後に発生し、その後 Claude Desktop を再起動しても解消しません。