My thought is: Could the tool-routing layer be a much simpler "old school" NLP model? Then it would never try to do math and end up doing it poorly, because it just doesn't know how to do that. But you could give it a calculator tool and teach it how to pass queries along to that tool. And you could also give it a "send this to a people LLM tool" for anything that doesn't have another more targeted tool registered.
Is anyone doing it this way?