Chrome extension MCP tools report 'not connected' despite successful pairing (macOS, v2.1.90)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is reproducible with the latest version of Claude Code

Environment

• Claude Code: v2.1.90
• Chrome extension: v1.0.66 (Claude in Chrome Beta)
• OS: macOS Darwin 25.3.0 (Mac Mini)
• Chrome: 146.0.7680.165

Bug Description

mcp__claude-in-chrome__tabs_context_mcp always returns "Browser extension is not connected" despite:

1. Extension installed and enabled in Chrome (Default profile)
2. pairing.html completed — browser named and Connect clicked
3. Both CLI and Chrome extension connected to bridge.claudeusercontent.com (verified via lsof)
4. Native messaging host running and creating socket at /tmp/claude-mcp-browser-bridge-<user>/
5. browserControlPermissionAccepted: true in extension storage
6. chrome_ext_bridge_enabled: true in extension storage
7. CLI and Chrome logged into same claude.ai account (verified)
8. Extension has nativeMessaging permission granted
9. Only one Chrome profile has extension enabled

What works

• Same setup works on Linux (Ubuntu, Claude Code v2.1.87, Chrome extension v1.0.66)
• The --chrome flag is passed to CLI
• Cloud bridge server is reachable (426 on HTTPS, WebSocket upgrade works)

Diagnostic details

• CLI (PID 53683, claude --chrome) has TCP connections to 160.79.104.10:443 (bridge)
• Chrome (PID 68328) also has TCP connections to 160.79.104.10:443
• Native host creates local unix socket but has NO TCP connections to bridge
• tengu_copper_bridge config value has no effect when --chrome flag is used
• Pairing page shows and completes successfully but MCP tools never connect
• Tested with 1 CLI session and 2 CLI sessions — same result
• No runtime errors in extension's Secure Preferences

Steps to reproduce

1. Install Chrome extension v1.0.66 on macOS
2. Log into claude.ai in Chrome
3. Run claude --chrome in terminal
4. Open Claude side panel (Cmd+E)
5. Complete pairing at chrome-extension://fcoeoabgfenejglbffodgkkbkcdhcgfn/pairing.html
6. Call mcp__claude-in-chrome__tabs_context_mcp — always returns "not connected"

Expected behavior

After pairing, MCP chrome tools should connect and return tab context.