I currently use cursor with Claude 4 Sonnet (thinking) in agent mode and it is absolutely crushing it.
Last night i had it refactor some Django / react / vite / Postgres code for me to speed up data loading over websocket and it managed to:
- add binary websocket support via a custom hook - added missing indexes to the model - clean up the data structure of the payload - add messagepack and gzip compression - document everything it did - add caching - write tests - write and use scripts while doing the optimizations to verify that the approaches it was attempting actually sped up the transfer
All entirely unattended. I just walked away for 10 minutes and had a sandwich.
The best part is that the code it wrote is concise, clean, and even stylistically similar to the existing codebase.
If claude code can improve on that I would love to know what I am missing!