Claude in Chrome extension not connecting to browser tabs - "Receiving end does not exist" error

The Claude in Chrome extension fails to connect to browser tabs. Claude Code can connect to the extension's MCP server (confirmed in
debug logs), but the extension itself cannot communicate with browser tabs.

Environment:

• macOS: Darwin 23.6.0
• Claude Code: v2.1.19
• Chrome Extension: v1.0.40
• Chrome version: 144.0.7559.97

Steps to reproduce:

1. Install Claude in Chrome extension
2. Start Claude Code with claude --chrome
3. Attempt to use any browser automation tool (e.g., tabs_context_mcp)
4. Receive "Browser extension is not connected" error

Debug log findings:

MCP connection succeeds:
MCP server "claude-in-chrome": Successfully connected to stdio server in 556ms
MCP server "claude-in-chrome": Connection established with capabilities: {"hasTools":true...}

But tool calls return "not connected" from the extension.

Console errors from extension sidepanel:
Uncaught (in promise) Error: Could not establish connection. Receiving end does not exist.

Also seeing CSP violations:
Executing inline script violates the following Content Security Policy directive 'script-src 'self''

Troubleshooting attempted:

• Restarted Chrome completely (Cmd+Q)
• Restarted Claude Code
• Used "Reconnect extension" option in /chrome menu
• Uninstalled and reinstalled extension
• Verified using correct Chrome profile (Profile 1 where extension is installed)

None of these resolved the issue.