Have you tried and failed, or you're just worried it might be hard? When I first set up a client for API calls, I put this paragraph in my system prompt:

> Never ask questions or attempt to keep the conversation going -- answer the questions directly asked, and give additional information where it is likely to be helpful, but don't offer to do more things for the user.

I've never had an LLM offer to do things or try to keep the conversation going with this in my prompt.