Claude in Chrome: extension not connecting (native messaging silent failure)

Description

mcp__claude-in-chrome__* tools consistently fail with:

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.

This happens despite the extension being installed, enabled, and working correctly with the Claude Desktop app (and having previously worked with Claude Code in past sessions).

Environment

• Claude Code version: 2.1.209
• OS: macOS (Darwin 25.5.0)
• Chrome version: 150.0.7871.49
• Claude in Chrome extension version: 1.0.80 (ID fcoeoabgfenejglbffodgkkbkcdhcgfn)

Troubleshooting already performed

• Verified native messaging host manifest exists and is correct: ~/Library/Application Support/Google/Chrome/NativeMessagingHosts/com.anthropic.claude_code_browser_extension.json, pointing to a valid, executable wrapper script that execs the currently-running Claude Code binary (~/.local/share/claude/versions/2.1.209 --chrome-native-host)
• Confirmed extension is installed in the correct (Default) Chrome profile and matches the allowed_origins extension ID in the manifest
• Confirmed logged into claude.ai in Chrome with the same account used by Claude Code CLI
• Fully quit (Cmd+Q) and restarted Chrome — confirmed via new PID/start time — issue persists
• Ran /chrome → "Reconnect extension" in Claude Code — opens a claude.ai/new tab that closes almost instantly with no visible error or status update
• Opened the extension's service worker DevTools console (chrome://extensions → Developer mode → "service worker") and watched it during a reconnect attempt — no errors or log output appear at all, on either the extension side or in Claude Code's tool response
• Fully uninstalled and reinstalled the extension — issue persists
• Extension works correctly with Claude Desktop app using the same claude.ai account

Expected behavior

The extension should connect to Claude Code CLI (as it has in prior sessions on this same machine), or the reconnect/pairing flow should surface a visible error explaining the failure instead of silently opening and closing a tab.

Actual behavior

Connection silently fails with no diagnostic information in either the extension's console or Claude Code's output, despite all local configuration appearing correct.