[BUG] Browser automation screenshot action times out on all sites (Script injection timeout / document_idle wait)

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?

Environment:

OS: Windows 11 Pro (10.0.26100)
Client: Claude Code (desktop app)
Affected tools: Browser pane (computer action, screenshot/zoom) and Claude in Chrome extension (computer action, screenshot)
Description:
The screenshot action (and zoom) on both the built-in Browser pane and the Claude in Chrome extension consistently times out, even though page navigation and DOM reads succeed.

What Should Happen?

Errors observed:

Browser pane: computer timed out after 30s. The Browser pane may be stuck (modal dialog, navigation hang, or unresponsive renderer).
Claude in Chrome: Error capturing screenshot: Script injection timed out after 5000ms — the page is busy or mid-navigation...
Claude in Chrome read_page: Failed to read page: Page still loading (executeScript waited 45000ms for document_idle).

Error Messages/Logs

Steps to Reproduce

Reproduction steps:

Start any local static server (e.g. python -m http.server 8791) serving a simple static HTML site.
Navigate the Browser pane or Claude in Chrome tab to http://localhost:8791/index.html. Page loads fully (title updates, all network requests return 200/304).
Call the screenshot action on that tab → times out.
Isolation test: navigate to https://example.com (unrelated external site, no local server involved) → screenshot still times out identically.
Confirmed extension is enabled, has tab permissions, and no pending permission dialogs are blocking the tab.
Fully restarted the Claude Code desktop app and retried → identical failure persists.
Expected behavior: screenshot/zoom returns an image of the rendered page.

Actual behavior: Times out on every site tested (both local and external), on both browser automation surfaces, before and after a full app restart.

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude 1.20186.9 (69f150) 2026-07-14T05:52:31.000Z

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_