[BUG] Claude in Chrome: screenshots show false blank gap above page content after scrolling (Windows)

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?

Setup: scheduled task in Claude Code configured in windows Claude Desktop App which does some UI testing and can file github bugs.

When using Claude in Chrome's computer tool to take screenshots after scrolling, the captured image contains a large dark/blank gap (~300-400px) at the top of the viewport that doesn't exist in the actual browser rendering. The gap grows with continued scrolling. After several scroll + screenshot cycles, the page renderer can freeze entirely (CDP Page.captureScreenshot times out after 30s).

This caused Claude to incorrectly diagnose a "rendering bug" in a web application being tested, file a false bug report, and miss evaluating actual UI content because it believed the page was broken.

Reproduced on two independent sites:

• https://www.cnn.com (major news site with sticky navbar)
• https://github.com/anthropics/claude-code (GitHub repo page)

so the bug doesn't appear to be site specific - it may affect any page after scrolling via the computer tool's scroll action.

<!-- ATTACH SCREENSHOTS HERE:

1. "Before scroll" screenshot showing correct rendering (navbar at top, content fills viewport)

<img width="757" height="568" alt="Image" src="https://github.com/user-attachments/assets/49f6b853-f812-4020-860b-f96547922bac" />

1. "After scroll" screenshot showing dark gap at top, navbar displaced to middle of frame

<img width="907" height="601" alt="Image" src="https://github.com/user-attachments/assets/33ada88c-6493-4f69-9de1-727da4b132e5" />

can also reproduce in Cowork

<img width="1851" height="1278" alt="Image" src="https://github.com/user-attachments/assets/c5c5c694-ce85-4084-bd3a-a9536c211cfd" />

The issue appears to be in how the Chrome MCP extension captures the viewport bounds after a scroll event. The captured region seems to include space above the actual viewport (possibly the tab group UI or extension chrome), pushing real page content down in the frame.

This makes scroll-dependent UI analysis unreliable — Claude misinterprets the gap as a CSS layout bug in the target application.

What Should Happen?

Screenshots taken after scrolling should capture the viewport as the user sees it — sticky navbar at the top of the frame, content below, no gaps. The captured image should match what a human user sees in the browser at that scroll position.

Error Messages/Logs

screenshots included above

Steps to Reproduce

instruct claude code to walk through a UI flow which requires scrolling. Note in it's reasoning trace captured screenshots with large dark space in top part post scroll

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

not sure if it's a regression or just never worked

Claude Code Version

2.1.92

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Other

Additional Information

Additional Information

using "Code" section of Claude windows desktop app which has the built in "Claude in Chrome" tool

• OS: Windows 11 Home 10.0.26200
• Chrome: 146.0.0.0
• Claude Code: Latest (Claude Opus 4.6, 1M context)
• Display scaling: Default Windows scaling