Claude in Chrome extension not connecting despite correct configuration

Description

The Claude in Chrome browser extension fails to connect to Claude Code despite all configuration being correct. The connection was working previously and broke on February 12, 2026.

Environment

• Claude Code Version: 2.1.39
• Chrome Extension Version: 1.0.49 (Claude in Chrome Beta)
• Extension ID: fcoeoabgfenejglbffodgkkbkcdhcgfn
• OS: macOS (Darwin 24.5.0)
• Chrome: Google Chrome (latest)

Symptoms

When attempting to use any Chrome browser automation tools:

Browser extension is not connected. Please ensure the Claude browser extension 
is installed and running (https://claude.ai/chrome), and that you are logged 
into claude.ai with the same account as Claude Code.

What We Verified ✓

1. Extension installed and enabled

• Verified in chrome://extensions/
• Extension ID matches: fcoeoabgfenejglbffodgkkbkcdhcgfn
• Extension toggle is ON

1. Native messaging host configuration exists and is correct

``json
{
"name": "com.anthropic.claude_code_browser_extension",
"description": "Claude Code Browser Extension Native Host",
"path": "~/.claude/chrome/chrome-native-host",
"type": "stdio",
"allowed_origins": [
"chrome-extension://fcoeoabgfenejglbffodgkkbkcdhcgfn/"
]
}
`
Location: ~/Library/Application Support/Google/Chrome/NativeMessagingHosts/com.anthropic.claude_code_browser_extension.json`

1. Native host binary exists and is executable

``bash
-rwxr-xr-x 1 co staff 170 Feb 10 18:11 ~/.claude/chrome/chrome-native-host
`
Content:
`bash
#!/bin/sh
# Chrome native host wrapper script
# Generated by Claude Code - do not edit manually
exec "~/.local/share/claude/versions/2.1.39" --chrome-native-host
``

1. Claude Code binary exists

``bash
-rwxr-xr-x 1 co staff 182876336 Feb 10 18:09 ~/.local/share/claude/versions/2.1.39
``

1. /chrome command status

• Status: Enabled
• Extension: Installed
• Enabled by default: Yes

1. No errors in extension console

• Checked extension service worker console
• No connection errors or warnings visible

1. User logged into claude.ai

• Confirmed logged in with account that has Max plan
• Same browser where extension is installed

What We Tried (All Failed)

1. ✗ Restarted Chrome multiple times
2. ✗ Restarted Claude Code multiple times
3. ✗ Uninstalled and reinstalled Chrome extension
4. ✗ Ran /chrome and selected "Reconnect extension"
5. ✗ Started Claude Code with claude --chrome flag
6. ✗ Verified extension ID matches config
7. ✗ Checked all file permissions
8. ✗ Removed incorrect WebSocket config that was accidentally created

Timeline

• Previous: Connection was working normally
• February 12, 2026: Connection stopped working
• No known changes: User doesn't recall updating Chrome, Claude Code, or the extension

Expected Behavior

The Chrome extension should connect to Claude Code via native messaging, allowing browser automation commands to work.

Actual Behavior

The extension appears installed and enabled in /chrome status, but all browser automation tool calls fail with "Browser extension is not connected".

Workaround

Switched to Puppeteer MCP server as alternative for browser automation:

{
  "mcpServers": {
    "puppeteer": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-puppeteer"]
    }
  }
}

Additional Context

Everything in the configuration chain appears correct:

• Extension installed with matching ID
• Native messaging host file exists with correct extension ID
• Native host script points to correct Claude Code binary
• All files have correct permissions

Yet the connection still fails. This suggests either:

1. A recent update broke compatibility (Chrome, macOS, Claude Code, or extension)
2. A macOS security/permission issue is blocking native messaging
3. An authentication/account mismatch issue not visible in logs

Reproduction Steps

1. Install Claude in Chrome extension version 1.0.49
2. Install Claude Code version 2.1.39
3. Verify native messaging host exists
4. Restart both Chrome and Claude Code
5. Run /chrome - shows as "Enabled" and "Installed"
6. Try any browser automation tool (e.g., tabs_context_mcp)
7. Observe "Browser extension is not connected" error

Request

Please investigate why the native messaging connection fails despite all configuration being correct. Are there any hidden logs or diagnostic commands that could reveal what's blocking the connection?