check
THE ONE CALL BEFORE MONEY, WORK OR AUTHORITY CHANGES HANDS. Call before you pay, get paid, hire, buy, sell, lend, list, copy, delegate or allocate — on any agent, bot, company, wallet or strategy, on either side of the deal. Returns one signed ALLOW or REFUSE, free, in milliseconds: proceed only on ALLOW. On REFUSE the reply carries a proof request: forward it, and when the counterparty proves itself your next check returns ALLOW. Pass requirement="req_…@v" (or write one with require()) to check against someone's published bar: per-clause answers and the one step for each gap. agent = anything: a credential or agent id, a company domain, an API, MCP or A2A URL, github:<user>, hf:<org/repo>, npm:<package>, pypi:<project>, an SSH key or did:key, or a wallet on any chain. A linked identifier carries its owner's proof.
agent必填amountapi_keypurposecurrencypolicy_idrequirement