Claude in Chrome extension won't connect despite correct account, enabled state, and full browser restart

Description

The Claude in Chrome extension consistently reports "Browser extension is not connected" from the Claude Code CLI side, even after working through the full standard troubleshooting checklist.

What I verified before filing

• Extension installed: confirmed present at chrome://extensions (Claude — "Claude in Chrome").
• Extension enabled: the toggle in chrome://extensions is on.
• Correct account: opened the extension's own "Claude in Chrome settings" page (Permissions tab) — it shows logged in as the same account used by this Claude Code CLI session.
• Icon pinned and clickable: pinned the extension icon to the toolbar; clicking it opens a side panel ("Claude" chat panel with a model selector), so the extension itself is clearly running.
• Full browser restart: fully quit Chrome (not just closed windows) and relaunched it, then waited several seconds before retrying — no change.

Despite all of the above, every call to the tabs_context_mcp tool (and other mcp__claude-in-chrome__* tools) from the Claude Code CLI session returns:

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. If this is your first time connecting to Chrome, you may need to restart Chrome for the installation to take effect. If you continue to experience issues, please report a bug: https://github.com/anthropics/claude-code/issues/new?labels=bug,claude-in-chrome

Environment

• OS: macOS (Darwin)
• Browser: Google Chrome, single profile ("Default")
• Claude Code: CLI session with mcp__claude-in-chrome__* tools available

Expected behavior

Once the extension is installed, enabled, logged into the matching account, and Chrome has been fully restarted, the CLI session should be able to connect to it via the mcp__claude-in-chrome__* tools.

Actual behavior

Connection attempts consistently fail with the "not connected" error above, with no further diagnostic detail surfaced to either the extension UI or the CLI session.