[BUG] Claude in Chrome: "Browser URL could not be parsed" on all tabs after reconnection

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

After the Chrome extension disconnects and reconnects mid-session, all browser automation tools (computer, javascript_tool, get_page_text, etc.) fail with:

Browser URL could not be parsed. Check the format and try again.

The extension reports as connected (tabs_context_mcp returns valid tab IDs and URLs), but any interaction with those tabs fails. This affects every tab and every site, not just specific URLs.

What Should Happen?

Browser automation tools should work normally after reconnection, the same as the initial connection.

Error Messages/Logs

# Every tool call returns:
Browser URL could not be parsed. Check the format and try again.

# Meanwhile tabs_context_mcp returns valid data:
{"availableTabs":[{"tabId":1203562586,"title":"Zartis Top Priorities - Google Sheets","url":"https://docs.google.com/spreadsheets/d/..."}],"tabGroupId":1668667311}

Steps to Reproduce

1. Start a Cowork session with Claude in Chrome connected
2. Use browser automation tools successfully on any site (e.g. Google Sheets)
3. Wait for the extension to disconnect (happens after idle period or Chrome restart)
4. Reconnect the extension (via dialog or toolbar icon)
5. Attempt any browser tool call (screenshot, javascript_tool, computer, etc.)
6. Observe: tabs_context_mcp and navigate work, but all other tools fail

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Worked on the same version (v1.0.64) before the first disconnection in the session.

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Other

Additional Information

• The error initially appeared related to Google Sheets URLs with #gid= fragments, but testing confirmed it affects all sites (google.com, chrome://newtab/, etc.)

• tabs_context_mcp correctly reports URLs with fragments — the parsing issue is in the tool execution layer, not tab management

• Remediation attempts that did NOT fix the issue:

• Creating new tabs and navigating to fresh URLs
• Toggling the extension off/on in chrome://extensions
• Uninstalling and reinstalling the extension