Is there a way to persuade a GPT to use RAG rather than CI?

My custom GPT always wants to use Code Interpreter to write a script to parse my knowledge file, even though it would do better if it would use RAG and just examine the most relevant chunks. I have tried instructing it in both the GPT instructions and the chat. I have tried forcing the knowledge file into a markdown file, but it always wants to write code and parse the file

Is your use-case one that would allow you to simply turn off code interpreter?
It should still be able to use retrieval without it.

Yes, I have resorted to that, and it may be the best compromise, but in some cases I do need to combine them and having some way of influencing what is used would be very useful.