An x402 payment settles on-chain, and the server does not reverse it because you later decide the data was not what you expected. The only moment when you can still walk away for free is the unpaid request: the 402 response. That response is the real specification of a paid endpoint — the price, the network, the asset, the recipient and the fact that the endpoint answers at all. The problem is that a catalogue entry is not that specification. It is a copy of what the seller typed when the r...