Glossary
Terminology in this field isn't settled; the same word often means different things in different documents. What follows is what OceanAlt means by each term in our own writing — not an industry-agreed definition, but our working one, so you can read us precisely.
- x402
- KYA (Know Your Agent)
- Mandate
- Prompt injection
- Facilitator
- Settlement
- Nonce
- RAP (Responsible Agentic Payments)
- AML screening
- Agent economy
- x402
A machine-payment interaction built on the HTTP 402 status code: the server answers an unpaid request with a 402 and a quote (amount, payee, one-time nonce); the client signs a payment authorization and retries the same request carrying that credential; the server verifies and releases the resource. The point is that no account and no API key are required — the payment is the identity. We implement the full round-trip in 200Lab, and you can run it yourself.
- KYA (Know Your Agent)
Attributing identity to an AI agent that initiates payments: who it is, which legal entity stands behind it, what it is authorized to do, and whether that authorization can be revoked. The difference from KYC is the subject — KYC identifies a person, KYA identifies the program spending on that person's behalf. Worth stressing: KYA only answers who is behind it. That is not payment security in itself; the real protection is enforcement before the money leaves.
- Mandate
The boundary within which an agent may spend — typically a per-payment cap, a daily cumulative cap, a payee allowlist and a stated purpose. It has to be enforced by a system outside the agent: a limit written into a prompt is not a mandate, because an agent's reasoning can be poisoned. Our gateway checks each of these before settlement and compares the intent of the payment against the original mandate.
- Prompt injection
Hiding malicious instructions inside content an agent will read — a web page, an email, a tool's return value — to make it act against its operator's intent. In payments the classic outcome is a changed payee or amount. We tested this against our own implementation in the Attack Lab: the injected agent did emit the redirected payment, but the request was stopped before settlement by the mandate-intent check. Which is the point: the trust layer has to live outside the agent.
- Facilitator
A third party that verifies payment credentials and settles funds on a merchant's behalf in x402-style protocols, so the merchant doesn't have to run chain infrastructure, custody wallets or handle clearing. It is the role closest to a traditional payment institution in this stack — and therefore the most likely place for regulation to land: whoever facilitates carries the compliance responsibility for the money flow.
- Settlement
The step at which funds actually move and reach finality. It's worth separating two things that get conflated: a payment authorization passing verification (protocol layer) is not the same as money having arrived (settlement layer). Our demos distinguish simulated settlement from real testnet settlement, and the latter always comes with a block-explorer link.
- Nonce
A unique value carried by each payment, consumed once before settlement; a repeat means replay. Without it, a legitimate payment that passed every compliance check can be resent verbatim any number of times — because each instance, viewed on its own, is perfectly compliant. This is the gate we added after breaking our own implementation in Attack Lab episode 5.
- RAP (Responsible Agentic Payments)
An open, protocol-neutral framework proposed by OceanAlt, built on seven pillars: attribution, mandate and limits, firewall, AML screening, auditability, privacy, and interoperability. It is not tied to any particular protocol or settlement rail; the aim is to give the question of how an agent payment should be constrained a citable common vocabulary.
- AML screening
Checking a counterparty address against sanctions lists, mixers and other risk signals before releasing funds. The boundary matters: we currently run list screening plus on-chain heuristics for Ethereum-family addresses, but for Tron we run list screening only, with no on-chain heuristics yet. We state that on the page rather than glossing over it.
- Agent economy
Economic activity in which AI agents act as transacting parties: discovering services, negotiating prices, ordering and paying on behalf of people or companies, and buying and selling data, compute, models and tool capabilities from each other. What separates it from AI-as-efficiency-gain is that the agent isn't only a tool — it's a party on the ledger.