Claude in Chrome extension not connecting despite MCP server showing connected

[chuck-markin-IS]

Preflight Checklist

• I have searched existing issues and this hasn't been reported yet
• This is a single bug report (please file separate reports for different bugs)
• I am using the latest version of Claude Code

What's Wrong?

Environment:

• OS: Windows
• Claude Code version: 2.1.23
• Chrome extension: Claude in Chrome (beta)
• Chrome version: [please add your Chrome version - find it at chrome://settings/help]

Description:
The Claude in Chrome browser extension fails to connect from Claude Code, even though the MCP server shows as connected.

Steps to reproduce:

1. Install Claude in Chrome (beta) extension
2. Enable extension with "On all sites" permission
3. Run Claude Code CLI
4. Run /mcp - shows claude-in-chrome server is connected
5. Attempt to use any browser automation tool (e.g., tabs_context_mcp)
6. Receive error: "Browser extension is not connected"

Troubleshooting attempted:

• Uninstalled and reinstalled the Chrome extension
• Restarted Chrome completely
• Verified extension permissions ("On all sites" enabled)
• Reconnected MCP server via /mcp
• Checked extension DevTools console - no errors
• Extension sidebar opens normally

Expected behavior:
Browser automation tools should connect to the Chrome extension when MCP server shows connected.

Actual behavior:
All browser automation tool calls return "Browser extension is not connected" error.

Chrome Version: 144.0.7559.97

What Should Happen?

Claude should connect to my browser. Everything was working fine until yesterday.

Error Messages/Logs

Steps to Reproduce

1. Install Claude in Chrome (beta) extension from Chrome Web Store
2. Enable extension with "On all sites" site access permission 3. Open Claude Code CLI in terminal
3. Run /mcp - confirm claude-in-chrome server shows as connected
4. Attempt any browser automation (e.g., ask Claude to browse to a URL)
5. Tool call to tabs_context_mcp returns error: "Browser extension is not connected"

Additional info:

• Reinstalling extension does not fix
• Restarting Chrome does not fix
• Reconnecting MCP via /mcp does not fix
• No errors visible in extension's DevTools console

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.23

Claude Code Version

2.1.23

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

No response

[github-actions]

Found 3 possible duplicate issues:

1. [BUG] Chrome native host and Claude Code compete for same named pipe (EADDRINUSE on Windows) #21753
2. [BUG] MCP tools fail with "Browser extension is not connected" despite /chrome showing Connected #20862
3. Claude in Chrome extension not connecting on Windows despite MCP server showing "connected" #21300

This issue will be automatically closed as a duplicate in 3 days.

• If your issue is a duplicate, please close it and 👍 the existing issue instead
• To prevent auto-closure, add a comment or 👎 this comment

🤖 Generated with Claude Code

[jspicher]

Downgrading to 2.1.19 fixed it for me. Ran npm install -g @anthropic-ai/claude-code@2.1.19 and the extension connected right away.

[kimchi-developer]

Root cause found and documented in #21791: The \ function (socket path discovery) doesn't return Windows named pipe path. Fix: add \ at the start of the function.

See detailed analysis: #21791 (comment)

[advancedAgritek-BB]

I’m experiencing the same issue on Mac.

[localden]

Thank you for your report — we are currently in the process of triaging MCP-related issues and this one appears to describe the same problem as #21337. To keep the discussion and any fix in one place, we're consolidating into that issue and closing this one. If you have logs, repro steps, or environment details that aren't already covered in #21337, please add them there — it'll help us track this down faster.