Some basic things it fails at:
* Upgrading the React code-base from Material-UI V4 → V5
* Implementing a simple header navigation dropdown in HTML/CSS that looks decent and is usable (it kept having bugs with hovering, wrong sizes, padding, responsiveness, duplicated code etc.)
* Changing anything. About half of the time, it keeps saying "I made those changes", but no changes were made (it happens with all of them, Windsurf, Copilot, etc.).