Claude in Chrome: "Browser extension is not connected" after extension updated to broker architecture — connection attempts never reach the extension
Environment: macOS (Darwin 25.5.0), Claude Code 2.1.198, Claude desktop app installed (Electron 1.11187.1), Chrome current, extension ID fcoeoabgfenejglbffodgkkbkcdhcgfn
Worked until: ~July 2, 2026 (Claude Code 2.1.175, old per-CLI native host wrapper at ~/.claude/chrome/chrome-native-host)
Symptoms:
- Every tabs_context_mcp call returns "Browser extension is not connected"
- The extension launches the broker fine: /Applications/Claude.app/Contents/Helpers/chrome-native-host runs and holds /tmp/claude-mcp-browser-bridge-<user>/<pid>.sock
- Extension service worker console + network tabs show zero activity during CLI connection attempts — the attempt never reaches the extension
Ruled out: stale CLI process (fresh 2.1.198 via claude --continue), stale broker (killed/respawned several times), stale sockets (cleaned), MCP staleness (/mcp reconnect after every broker bounce, correct ordering), claude.ai account mismatch (found and fixed mid-debugging — did not resolve), extension disable/enable, multiple full Chrome restarts, quitting the Claude desktop app, full macOS reboot.
Note: both native host manifests exist in ~/Library/Application Support/Google/Chrome/NativeMessagingHosts/ — the old com.anthropic.claude_code_browser_extension (pointing at ~/.claude/chrome/) and the new com.anthropic.claude_browser_extension (pointing at the desktop app helper). The extension consistently launches the new one.
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