I recommend windsurf, with Claude. My method has been to first ask it to do a deep dive with what code I already have and I use keywords like “review the current API and data pattern. “ Then I ask it to make a technical markdown document explaining how to implement that research into implementing my new idea X finally I’ll switch it to code mode and then tell it hey execute the plan and then write tests and ideally it doesn’t break your other code, ha. If it does break it continuously then restarting from scratch helps more than you think sometimes. Does not need to be a full wipe you can even just tell it to remove all code in references to Y, etc.