For all LLMs, I´m using a simple prompt with the complete code in triple quotes and the command at the end, asking to output the complete code of changed functions. Then I use Winmerge to compare the changes and apply. I feel more confident doing this than using Cursor.
Should really check out aider. Automates this but also does things like make a repo map of all your functions / signatures for non-included files so it can get more context.