Claude in Chrome extension never connects to Claude Code CLI ("Browser extension is not connected")

Environment

• OS: macOS (Darwin 25.5.0)
• Claude Code CLI version: 2.1.203
• Claude in Chrome extension version: v1.0.80
• Extension ID: fcoeoabgfenejglbffodgkkbkcdhcgfn

Problem

Every claude-in-chrome MCP tool call (e.g. tabs_context_mcp) returns:

Browser extension is not connected. Please ensure the Claude browser extension is installed and running, and that you are logged into claude.ai with the same account as Claude Code.

The extension itself works fine as a standalone Chrome side panel (chats, reads pages, etc.) and is logged into the same Anthropic account as Claude Code CLI. However, Claude Code's MCP bridge never detects it as connected, so none of the mcp__claude-in-chrome__* tools work.

Steps already tried (none resolved it)

1. Verified the same Anthropic account is logged into both the Chrome extension and Claude Code CLI.
2. Fully quit and relaunched Chrome.
3. Disabled the desktop Claude.app's native messaging host manifest (~/Library/Application Support/Google/Chrome/NativeMessagingHosts/com.anthropic.claude_browser_extension.json, renamed with a suffix to disable it), on the theory that the extension was pairing with the desktop app's native host instead of Claude Code's own manifest (com.anthropic.claude_code_browser_extension.json).
4. Confirmed the --chrome-native-host process does spawn (visible via ps aux) when interacting with the extension in the browser.
5. Started a brand-new Claude Code CLI session and retried — still "not connected".
6. Fully removed and reinstalled the Chrome extension via chrome://extensions and claude.ai/chrome, then re-authenticated — still "not connected".

Additional context

Multiple Claude Code CLI sessions/background processes tend to run concurrently on this machine (daemons, multiple terminal sessions). It's possible the native-host socket/pairing is being claimed by a different process/session than the one issuing the MCP call, though this hasn't been confirmed as the root cause.

Expected behavior

tabs_context_mcp (or any claude-in-chrome tool) should detect the running, logged-in extension and return the current tab/browser context.