Chrome extension not connecting to Claude Code on Windows 11 — "Browser extension is not connected" despite correct setup

Environment

• OS: Windows 11 Home 10.0.26200
• Claude Code: desktop app
• Chrome extension: installed, enabled, up to date
• claude.ai: logged in with same account as Claude Code

What I did

1. Installed the Claude Chrome extension from claude.ai/chrome
2. Logged into claude.ai in Chrome with the same account used in Claude Code
3. Restarted Chrome
4. Uninstalled and reinstalled the extension
5. Restarted Chrome again
6. Confirmed extension is enabled in chrome://extensions/
7. Confirmed logged into claude.ai in Chrome (shows correct account/workspace)

What happens
Every call to mcp__claude-in-chrome__tabs_context_mcp returns:
"Browser extension is not connected. Please ensure the Claude browser extension is installed and running..."

The extension itself works — it opens a sidebar on claude.ai. But it never handshakes with Claude Code.

What I expected
The browser automation tools to connect so Claude Code can control Chrome.

Additional notes
The Claude sidebar extension's own AI confirmed Claude Code OAuth tokens are active at claude.ai/settings/claude-code
(multiple sessions visible). The extension and Claude Code are both authenticated to the same account but the
connection between them never establishes.