I am a novice to Cursor. I wonder how can I make it not break the existing code. I can ask it to compile after each edit and fix compiling errors, and after tha

I am a novice to Cursor. I wonder how can I make it not break the existing code. I can ask it to compile after each edit and fix compiling errors, and after that, run tests and fix failing tests? Won't that eat into my credit a lot? Should I use .cursirrules or prompt? I also wonder how to not add functionality I didn't ask for and not add any "improvements" unless I specifically asked. Right now I am in the middle of building a CRUD api with Cursor, it took longer to write code than I would have done it myself. After the code was written it took lots of time and credits to fix compilation errors. Now I asked it to fix failing unit tests, but either it can not find a solution or it applies something that gives a compilation error or breaks other tests. I've gone through almost all my monthly quota of fast calls in 10 hours.