[BUG] Claude in Chrome: screenshot, left_click, and javascript_tool fail with "Cannot access a chrome-extension:// URL" on Anthropic websites

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?

Claude in Chrome extension fails with Cannot access a chrome-extension:// URL of different extension when attempting to use debugger-based tools (screenshot, left_click, javascript_tool) on Anthropic's own websites: claude.ai and support.claude.com.

Failing tools: computer (screenshot, left_click, right_click, double_click, key, scroll), javascript_tool

Working tools: read_page, find, form_input, navigate, get_page_text

The issue affects ALL debugger-dependent operations (CDP protocol), while accessibility-tree-based tools continue to function normally. This effectively blocks visual interaction and full automation on Anthropic-owned domains.

What Should Happen?

Claude in Chrome should be able to interact with claude.ai and support.claude.com using all tools (screenshot, left_click, javascript_tool) the same way it interacts with any other website. All CDP-based tools should work on Anthropic's own domains.

Error Messages/Logs

Error clicking: Cannot access a chrome-extension:// URL of different extension

Failed to execute JavaScript: Cannot access a chrome-extension:// URL of different extension

Error capturing screenshot: Cannot access a chrome-extension:// URL of different extension

Steps to Reproduce

1. Open claude.ai or support.claude.com in a Claude in Chrome managed tab group
2. Use any of the following tools: computer (screenshot/left_click), javascript_tool
3. All debugger-based operations fail with: Cannot access a chrome-extension:// URL of different extension
4. Tools like read_page, find, form_input, navigate, and get_page_text continue to work normally
5. Creating new tabs and retrying does not resolve the issue

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Claude in Chrome extension (latest version)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

This issue appears related to #16239.

The root cause seems to be Chrome's cross-extension security boundary. The chrome.debugger API rejects attach() when the tab URL resolves to a chrome-extension:// origin. This may be triggered by Intercom widget iframes or other embedded extension content on Anthropic's websites.

Workaround attempted: Creating new tabs, navigating to different URLs first, then navigating to claude.ai — same error persists.

Affected domains: claude.ai, support.claude.com (both Anthropic-owned)

Impact: Users cannot use Claude in Chrome to automate tasks on Anthropic's own support site, creating a catch-22 where the tool cannot be used to file bug reports about itself.