Chrome MCP bridge: SDK reports connected but never connects to native host Unix socket

Description

Claude Desktop v1.1.4498 with Chrome extension v1.0.56 — the Chrome MCP SDK reports connected=true, authenticated=true, wsState=1 but never connects to the native host's Unix socket. All tabs_context_mcp calls return "No MCP tab groups found" despite an active Chrome tab group being visible.

Environment

• macOS: Darwin 25.4.0 (Sequoia)
• Claude Desktop: v1.1.4498
• Claude Code CLI: v2.1.44 (running inside Desktop app)
• Chrome: 145.0.7632.117
• Chrome extension: v1.0.56 (ID: fcoeoabgfenejglbffodgkkbkcdhcgfn)

Diagnostic Evidence

1. SDK thinks it's connected (from ~/Library/Logs/Claude/main.log)

[Claude in Chrome] ensureConnected called, connected=true, authenticated=true, wsState=1
[Claude in Chrome] Already connected and authenticated
chrome_bridge_tool_call_completed | tool_name: tabs_context_mcp

2. Native host is running and listening (from ~/Library/Logs/Claude/chrome-native-host.log)

Chrome native host starting (version 0.1.0)
Socket created successfully at: /tmp/claude-mcp-browser-bridge-mike/74587.sock
Socket server listening for connections

3. No process connects to the socket

lsof -U confirms:

• chrome-native-host (PID 74587) has fd10 listening on /tmp/claude-mcp-browser-bridge-mike/74587.sock
• Neither Claude.app (73593) nor claude-code (73924) have any connection to this socket
• The native host log never shows an accepted connection

4. Chrome tab group exists

Screenshot confirms an active orange "Claude" MCP tab group in Chrome. Extension is installed, logged in, and functional.

Root Cause Analysis

The MCP SDK's connected=true appears to reference an internal WebSocket within the Claude app architecture, NOT the Unix socket bridge to Chrome. The SDK never discovers or connects to /tmp/claude-mcp-browser-bridge-mike/<PID>.sock, so tool calls get a response from somewhere internal that says "no tab groups" without ever reaching Chrome.

Possibly Related

• #27625 (Fixed in v1.1.4088 — "Failed to get account UUID"). Current version is past that fix but exhibits a different symptom: no UUID error, just silent failure to connect to the socket.
• #26217, #21279, #24593 — similar "extension connected but MCP not working" reports.

Steps to Reproduce

1. Open Chrome with Claude extension installed and logged in
2. Open Claude Desktop, start a Claude Code session
3. Call tabs_context_mcp — returns "No MCP tab groups found"
4. Check lsof -U — no connection to the native host socket
5. Check main.log — SDK reports connected=true

Expected Behavior

The MCP SDK should connect to the native host's Unix socket at /tmp/claude-mcp-browser-bridge-mike/<PID>.sock and relay tool calls to Chrome.