claude --chrome: MCP shows connected but tool calls fail with 'Browser extension is not connected'

Bug: claude --chrome MCP connected but tool calls fail with "Browser extension is not connected"

Description

When launching Claude Code with --chrome, the /mcp status shows claude-in-chrome as connected, but all tool calls (e.g., tabs_context_mcp) return:

Browser extension is not connected. Please ensure the Claude browser extension is installed and running...

The MCP server and the Chrome extension appear to be running correctly independently, but the bridge between them is not functioning.

Environment

• Claude Code: 2.1.81
• Chrome extension: Claude in Chrome (Beta) v1.0.63
• macOS: 26.3.1 (Darwin 25.3.0, Apple Silicon)
• Chrome: Managed by organization (outsideinc.com)
• Extension source: "Added by a third-party" (enterprise-deployed via Chrome Web Store)
• Extension ID: fcoeoabgfenejglbffodgkkbkcdhcgfn

What I verified

• Extension is enabled and toggled on
• Logged into claude.ai in Chrome (same account as Claude Code)
• Restarted Chrome after extension install
• Launched Claude Code with claude --chrome
• /mcp shows claude-in-chrome · ✔ connected
• Native messaging host exists at ~/.claude/chrome/chrome-native-host and points to correct Claude Code binary
• Native messaging manifest at ~/Library/Application Support/Google/Chrome/NativeMessagingHosts/com.anthropic.claude_code_browser_extension.json has correct extension ID in allowed_origins
• Extension service worker DevTools console shows no errors
• Extension options page shows authenticated user

Additional context

• Initially saw an OAuth error: "Authorization failed — Redirect URI chrome-extension://fcoeoabgfenejglbffodgkkbkcdhcgfn/oauth_callback.html is not supported by client." This was resolved (unclear what fixed it — possibly re-auth or restart).
• Browser is enterprise-managed, which may or may not be relevant.
• There is also a second native messaging host (com.anthropic.claude_browser_extension.json) from Claude Desktop app — unsure if having both causes a conflict.

Expected behavior

Tool calls via claude --chrome should reach the Chrome extension and return tab/page data.

Actual behavior

Every tool call returns "Browser extension is not connected" despite MCP showing connected status.