Chrome extension: MCP server never connects to native host socket

Description

The claude --chrome MCP server process never connects to the Unix socket created by the Chrome native host, making browser automation tools non-functional in Claude Code. Claude Desktop's Chrome integration works fine with the same extension.

Environment

• Claude Code version: 2.1.80
• OS: macOS Darwin 23.4.0 (Sonoma)
• Chrome extension: Freshly installed from chrome web store

Symptoms

All mcp__claude-in-chrome__* tool calls return:

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

The MCP server shows as "connected" in /mcp, and tool calls show green dots / "Tabs read" in the UI, but the response content is always the "not connected" error.

Root Cause Investigation

The architecture is:

Chrome Extension → Native Host (stdio) → Unix Socket → MCP Server (claude --chrome)

What works:

• Chrome extension spawns the native host correctly
• Native host creates a Unix socket in /tmp/claude-mcp-browser-bridge-rob/<pid>.sock
• MCP server (claude --chrome) process starts and is reachable from Claude Code

What doesn't work:

• The MCP server has zero socket connections (verified via lsof -p <pid> | grep sock — empty output)
• It never connects to the native host's socket

Reproduction Steps

1. Install Chrome extension
2. Start Claude Code
3. Run any mcp__claude-in-chrome__* tool (e.g. tabs_context_mcp)
4. Observe "Browser extension is not connected" error
5. Verify with:

```bash
# Find processes
ps aux | grep "chrome-native-host" # Native host - running
ps aux | grep "claude --chrome" # MCP server - running

# Check native host has socket
ls /tmp/claude-mcp-browser-bridge-rob/ # Socket file exists

# Check MCP server socket connections
lsof -p <mcp_server_pid> | grep sock # EMPTY - this is the bug
```

Additional Notes

• Tried clean reinstall: removed all native host configs, ~/.claude/chrome, socket directory, extension, restarted Chrome and Claude Code. Same result.
• Claude Desktop's native host (/Applications/Claude.app/Contents/Helpers/chrome-native-host) works fine with the same extension
• When both Desktop and Code native host configs exist, Chrome always picks Desktop's (com.anthropic.claude_browser_extension alphabetically before com.anthropic.claude_code_browser_extension), which means Code never gets the connection even when Desktop is quit
• /mcp reconnect restarts the MCP server process but doesn't fix the socket connection issue