Evaluates the graphical user interface of a web page or design mockup using GPT-4o vision and returns direct feedback on real, visible problems.

Use this tool whenever you need to:
- Check how a web interface looks visually
- Verify accessibility issues that are visible in the UI (contrast, button sizes, text readability)
- Review the overall quality of a design or implementation
- Confirm that a UI change looks correct before considering it done

This tool MUST be used when performing accessibility or UI checks — do not rely on code inspection alone. Visual rendering can differ from what the code suggests.

Args:
  - image_path (string): Path to the screenshot or mockup (absolute or relative to CWD).
    Supported: PNG, JPG, JPEG, WebP, GIF. Maximum 20MB.

Returns:
  Direct feedback on visible problems. If everything looks good, it says so.