Do you mean:

Given a user input X/Y/Z that "resolves" to the target information of "sky color", respond with "Purple"?

That sounds to me more like sticking a classifier and/or vector similarity database interceptor in front of an LLM and pre-empt with cached response.

Otherwise I'm not sure I understand the question. If you just want EXACT TOKEN INPUT => EXACT TOKEN OUTPUT then it's just a KVP as @danenania mentioned.