Claude in Chrome Extension Not Connecting - Critical Errors in v1.0.41

Claude in Chrome Extension Not Connecting - Multiple Critical Errors

Environment

• OS: Windows 10 (Build 10.0.19045.6466)
• Chrome Version: Latest
• Claude Code CLI Version: 2.1.29
• Extension: Claude in Chrome (Beta) v1.0.41
• Extension ID: fcoeoabgfenejglbffodgkkbkcdhcgfn

Problem Description

The Claude in Chrome extension fails to connect with Claude Code CLI. When attempting to use MCP browser automation tools (e.g., mcp__claude-in-chrome__tabs_context_mcp), the connection fails with:

Browser extension is not connected. Please ensure the Claude browser extension is installed and running.

Critical Extension Errors

The extension console shows multiple critical errors that prevent it from functioning:

1. Connection Errors

sidepanel-CZxLGvD6.js:12 Uncaught (in promise) Error: Could not establish connection. Receiving end does not exist.

mcpPermissions-D8RnuVb0.js:3 Uncaught (in promise) Error: Could not establish connection. Receiving end does not exist.

2. Content Security Policy Violations

Executing inline script violates the following Content Security Policy directive 'script-src 'self''.

Loading the script 'https://cdn.segment.com/next-integrations/actions/amplitude-plugins/f12a4347e1080fb88155.js' violates CSP directive: "script-src 'self'".

3. Message Channel Errors

Error: A listener indicated an asynchronous response by returning true, but the message channel closed before a response was received

Troubleshooting Steps Attempted

Native Messaging Host Configuration

Created complete native messaging host setup:

1. Registry Key: HKEY_CURRENT_USER\Software\Google\Chrome\NativeMessagingHosts\com.anthropic.claude_chrome
2. Manifest JSON: C:\Users\Max\AppData\Local\claude\chrome\com.anthropic.claude_chrome.json

``json
{
"name": "com.anthropic.claude_chrome",
"description": "Claude Chrome Native Messaging Host",
"path": "C:\\Users\\Max\\AppData\\Local\\claude\\chrome\\claude-chrome-host.bat",
"type": "stdio",
"allowed_origins": [
"chrome-extension://fcoeoabgfenejglbffodgkkbkcdhcgfn/"
]
}
``

1. Batch Script: Created claude-chrome-host.bat to launch Node.js with Claude Code CLI

Other Steps Taken

• ✅ Verified extension installation and ID
• ✅ Multiple Chrome restarts
• ✅ Extension reinstallation (errors persist)
• ✅ Checked DevTools console for errors
• ✅ Verified Node.js and Claude Code CLI functionality

Observations

• No Node.js process launches when attempting MCP connection
• Extension errors appear immediately on load, before any connection attempt
• Same errors persist after complete extension reinstall
• Extension's internal components cannot communicate with each other

Root Cause

The extension has critical bugs that prevent:

1. Internal component communication (sidepanel, mcpPermissions, etc.)
2. Script loading due to CSP violations
3. MCP connection functionality

These are extension code issues, not configuration problems.

Expected Behavior

The extension should:

1. Load without CSP errors
2. Establish internal connections between components
3. Connect to Claude Code CLI via native messaging host
4. Enable MCP browser automation tools

Actual Behavior

Extension fails to load properly with multiple critical errors, making MCP integration completely non-functional.

Additional Notes

• The shortcut /claude-cli exists in extension settings but doesn't resolve the connection issue
• Extension appears to be in an unstable beta state
• Issue affects core MCP functionality, not just edge cases