Before prepare_x402_payment returns VOUCHER_ISSUED, the backend runs the spend through policy, risk, compliance, and credit. A deny returns POLICY_DECISION_DENIED (or a more specific code) and no voucher. Nothing in this pipeline produces a signature over the agent’s payment. The agent signs the voucher. SohoPay later attests the settlement batch with a hardware-backed key.

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What is checked

  • The agent grant is ACTIVE, and the payment fits its merchant, per-payment, daily, and lifetime limits.
  • The borrower has facility headroom. A reservation holds that headroom from voucher issue until capture or expiry, so two prepares cannot spend the same dollar.
  • The draw fits the borrower’s available facility and policy limits.
  • The borrower’s wallet passes sanctions screening.
  • Merchant familiarity. A first payment to a new merchant can deny with RISK_FIRST_TIME_MERCHANT. On an HTTP 402, retry the same order and the same idempotency key. That retry is the acceptance. Other denials are a stop.
  • The merchant is eligible to be paid. The chain still requires ACTIVE in the registry at settleBatch, which the off-chain check does not replace.
get_context reports what is likely allowed. Prepare rechecks. A context payload that says the agent can pay is not a voucher.

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Facilitator throttles

These are separate from spend policy. Each merchant is limited to 120 verifies per minute and 30 captures per minute.

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Next steps

Errors

How denials are labeled.

Borrower responsibility

Who authorized the limits policy enforces.