[BUG] ExitPlanMode tool fails with "stream closed" error, leaving plan mode stuck

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 ExitPlanMode tool is called, it fails with:
"Tool permission stream closed before response received"

Plan mode never exits and remains stuck. Sending new messages
doesn't help - responses appear but plan mode UI stays active.
Only a new session resets the state.

What Should Happen?

"Plan mode exits normally"

Error Messages/Logs

Steps to Reproduce

"Enter plan mode → call ExitPlanMode → observe error"

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.86

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_