My AI agents work great until someone asks something we didn't plan for. Keep adding rules, or rethink the whole approach?

I am building an AI assistant (multi-agent setup) that handles real day-to-day tasks for our users scheduling, answering questions, sending messages, that kind of thing. It works really well as long as the request matches a situation we've already thought about. The problem: the moment something slightly unexpected comes up, it just... doesn't handle it gracefully. Quick example. A user has two locations with the same working hours. When something needs to be assigned to one of them, the obvious human move is to go "hey, these two overlap which one did you mean?" My system has all the info it needs to notice this. But it doesn't ask. It just silently picks one (or none) and moves on, because nobody explicitly told it "in this exact situation, stop and ask." So my current fix is always the same: I add another rule. Another condition. Another "if this happens, do that." And it works until the next unanticipated case shows up, and we add yet another rule. It feels like we're playing whack-a-mole forever instead of the thing actually being smart. What's frustrating is it has all the tools, all the data, and detailed instructions. But it only does what it's explicitlytold to do, and never reasons about gaps or ambiguity on its own.