Very very clear, unambiguous, prompts and agent rules. Use strong language like "must" and "critical" and "never" etc. I would also try working on smaller sections of a large codebase at a time too if things are too inaccurate.

The AI coding tools are going to be looking at other files in the project to help with context. Ambiguity is the death of AI effectiveness. You have to keep things clear and so that may require addressing smaller sections at a time. Unless you can really configure the tools in ways to isolate things.

This is why I like tools that have a lot of control and are transparent. If you ask a tool what the full system and user prompt is and it doesn't tell you? Run away from that tool as fast as you can.

You need to have introspections here. You have to be able to see what causes a behavior you don't want and be able to correct it. Any tool that takes that away from you is one that won't work.