[BUG] Claude-in-Chrome MCP tools fail with "Browser extension is not connected" despite extension being connected

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?

Environment

• OS: Windows
• Claude Code version: 2.1.20
• Chrome version: 144.0.7559.97 (Official Build) (64-bit)
• Claude-in-Chrome extension: Latest from Chrome Web Store

Steps to Reproduce

1. Start Claude Code
2. Verify /mcp shows claude-in-chrome as connected
3. Run /chrome to reconnect (triggers Chrome activity)
4. Use any Claude-in-Chrome MCP tool (e.g., tabs_context_mcp)
5. Receive error: "Browser extension is not connected"

Troubleshooting Attempted

• Restarted Chrome
• Disabled and re-enabled the Chrome extension
• Completely removed and reinstalled the Chrome extension
• Restarted Claude Code
• Disabled other MCP servers (Trigger.dev) to rule out port conflicts
• Verified MCP server shows as connected in /mcp
• Verified extension shows connected status in Chrome

Expected Behavior

MCP tools should communicate with the Chrome extension when both sides report connected status.

Actual Behavior

MCP server is connected to Claude Code but cannot reach the Chrome extension, despite the extension being active and /chrome command triggering browser activity.

Additional Context

The /chrome slash command appears to have some communication path to Chrome (triggers visible tab refresh), but the MCP tool calls fail. This suggests a partial connection or two different communication channels where one works and one doesn't.

What Should Happen?

MCP tools should communicate with the Chrome extension when both sides report connected status.

Error Messages/Logs

Steps to Reproduce

1. Start Claude Code
2. Verify /mcp shows claude-in-chrome as connected
3. Run /chrome to reconnect (triggers Chrome activity)
4. Use any Claude-in-Chrome MCP tool (e.g., tabs_context_mcp)
5. Receive error: "Browser extension is not connected"

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.20

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_