Not sure that this is true. cursor agent mode is different from cursor code completion and cursor code completion is a legitimately novel model I believe.
I was surprised to learn this, but they made some interesting choices (like using sparse mixture-of-experts models for their tab completion model, to get high throughput/low latency).
Originally i think they used frontier models for their chat feature, but I believe theyve recently replaced that with something custom for their agent feature.
One thing people don't realize is there's also randomness in the answers. Also, some of the editors allow you to tweak temperature and others do not. This is why I found Roo Code extension to be better.
https://www.coplay.dev/blog/a-brief-history-of-cursor-s-tab-...