Claude in Chrome Extension Not Connecting on Windows 11

Bug Report: Claude in Chrome Extension Not Connecting

Environment

• OS: Windows 11 Home 25H2 (Build 26200.7705)
• Claude Code Version: 2.1.31
• Chrome Version: Latest (installed at C:\Program Files\Google\Chrome\Application\chrome.exe)
• Extension ID: fcoeoabgfenejglbffodgkkbkcdhcgfn
• Extension Version: 1.0.44

Issue

The Claude in Chrome browser extension never connects to Claude Code. The mcp__claude-in-chrome__tabs_context_mcp tool always returns "Browser extension is not connected."

Diagnostics Performed

1. Extension Status

• Extension is installed in Default profile
• Extension files exist at: %LOCALAPPDATA%\Google\Chrome\User Data\Default\Extensions\fcoeoabgfenejglbffodgkkbkcdhcgfn\1.0.44_0\
• User confirmed extension is enabled (toggle ON)
• User confirmed logged into claude.ai with same account as Claude Code (max subscription)

2. Native Messaging Host

Registry Entry:

HKCU\Software\Google\Chrome\NativeMessagingHosts\com.anthropic.claude_code_browser_extension
Value: C:\Users\jelbe\AppData\Roaming\Claude Code\ChromeNativeHost\com.anthropic.claude_code_browser_extension.json

Manifest Content:

{
  "name": "com.anthropic.claude_code_browser_extension",
  "description": "Claude Code Browser Extension Native Host",
  "path": "C:\Users\jelbe\.claude\chrome\chrome-native-host.bat",
  "type": "stdio",
  "allowed_origins": [
    "chrome-extension://fcoeoabgfenejglbffodgkkbkcdhcgfn/"
  ]
}

Batch File Content:

@echo off
"C:\Users\jelbe\.local\bin\claude.exe" --chrome-native-host

3. Direct Native Host Test

Running claude.exe --chrome-native-host directly outputs:

[Claude Chrome Native Host] Initializing...
[Claude Chrome Native Host] Creating socket listener: \.\pipe\claude-mcp-browser-bridge-jelbe

This confirms the native host CAN start and create the named pipe.

4. Named Pipe Status

When checking for Claude-related named pipes, none exist. The pipe is never created because the extension never triggers the native host.

5. Chrome Processes

Multiple claude.exe processes are running (Claude Code session active).
Chrome is running with multiple processes.

6. Troubleshooting Steps Attempted

1. ✅ Verified extension is enabled in chrome://extensions
2. ✅ Verified same account in browser and Claude Code
3. ✅ Restarted Chrome completely (taskkill /F /IM chrome.exe)
4. ✅ Restarted Chrome multiple times
5. ✅ Checked extension Service Worker console - no errors
6. ✅ Removed and reinstalled extension from Chrome Web Store
7. ✅ Recreated native host batch file
8. ✅ Recreated native host JSON manifest
9. ✅ Re-registered native host in Windows registry
10. ✅ Removed old Claude installation (v2.0.67 at C:\Tools\Claude)
11. ✅ Verified only one Chrome profile has extension
12. ✅ Opened claude.ai in Chrome before testing connection
13. ✅ Clicked Claude extension icon to activate

7. What Works

• Claude Code CLI works fine
• Xero MCP server works
• Gmail IMAP automation works
• All non-Chrome MCP functionality works

8. Suspected Issue

The Chrome extension is not initiating the native messaging connection to start the native host. The native host never gets called, so the named pipe is never created.

Possible causes:

• Extension not properly triggering native messaging
• Manifest mismatch between extension expectations and registered host
• Windows-specific native messaging issue
• Extension state not fully initialized even when "enabled"

Steps to Reproduce

1. Install Claude Code on Windows 11
2. Install Claude in Chrome extension from Chrome Web Store
3. Log into claude.ai with same account as Claude Code
4. Enable extension
5. Run any mcp__claude-in-chrome__* tool
6. Observe "Browser extension is not connected" error

Expected Behavior

The extension should connect and browser automation tools should work.

Actual Behavior

Connection never establishes. Named pipe never created.

User Impact

Cannot use browser automation features. User has tried multiple times over multiple sessions with no success.