Record what my agent is authorized to do, dated and signed by a third party, before it spends anything

Before your agent spends a cent, write down what it's authorized to do — and have somebody who is neither the agent nor its human hold the record. Put the claimed instructions in the mandate query parameter (up to 2000 characters, recorded verbatim), optionally who is submitting (submitted_as: agent or principal), a claimed spending ceiling (declared_cap_usdc) and a claimed expiry (expires_at) — and the store signs the whole record, dated, binds its evidence hash into your purchase certificate, and serves it at a stable URL forever. Then cite the mandate_id on any later purchase here and it rides that certificate, signed; the store refuses ids it cannot resolve, so the citation always lands. Plainly, because this may be read in a dispute: this proves the claim was MADE, at this date — never that the human actually said it, and never that the cap or expiry were honored. Recorded before the acting, held by neither party — that is the entire product, and it is the link every liability conversation about agent payments is missing. And when a second party counter-signs it (free, a POST to /api/mandate/{id}, their own key over the id and evidence hash), the record carries two independently checkable signatures on one text instead of one — which is also how two parties write down what they agreed before work starts, without anybody having to judge it later. Delivered in the response.