Pipe conflict: Claude Code and native host fighting over claude-mcp-browser-bridge-apirr (EADDRINUSE)

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?

Claude Code and the native host (from the Chrome extension Beta) are fighting over the same named pipe (claude-mcp-browser-bridge-apirr). This creates a conflict where one process cannot bind to the pipe because the other already has it open.

This appears to be a resource conflict in the Beta extension where both Claude Code and the browser extension's native messaging host try to use the same pipe name simultaneously.

What Should Happen?

Claude Code and the browser extension should be able to run simultaneously without pipe conflicts. Each should have its own unique pipe identifier or they should coordinate access to shared resources.

Error Messages/Logs

Error: EADDRINUSE: address already in use \\.\pipe\claude-mcp-browser-bridge-apirr

Chrome extension error: "message channel closed before response received"

Steps to Reproduce

1. Have the Claude Browser Connector (Beta) Chrome extension installed and running
2. Launch Claude Code
3. Both attempt to use the named pipe claude-mcp-browser-bridge-apirr
4. One process fails with EADDRINUSE error
5. Chrome extension shows "message channel closed before response received"

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.29 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

This issue occurs when using the Claude Browser Connector (Beta) Chrome extension alongside Claude Code on Windows 10. The conflict appears to be a race condition or resource contention issue where both applications attempt to claim the same named pipe for MCP browser bridge communication.

Note: Please run claude --version and add the version number to the "Claude Code Version" field above before submitting.