A paywalled request is consent to pay that order. Complete the 402 path in one turn. Do not ask the borrower to approve the same merchant again when they already sent the agent to pay. The agent calls MCP. The merchant calls the facilitator. Those are different credentials and different retries. x402 payment sequence from HTTP 402 through voucher signing, facilitator capture, batched Base settlement, and confirmation x402 payment sequence from HTTP 402 through voucher signing, facilitator capture, batched Base settlement, and confirmation

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Agent

1

Read the 402

Use the merchant’s payment requirement as-is. Keep orderRef stable. One orderRef uses one payment Idempotency-Key for every retry, including after a policy accept or an expired intent.
2

Prepare

Call prepare_x402_payment. It creates or resumes the spend intent, runs policy, reserves credit, and on allow returns VOUCHER_ISSUED with an unsigned voucher.get_context can say a payment looks allowed. Prepare still rechecks. Do not skip prepare because context looked fine.
3

Sign

Sign with @sohopay/agent-signer and send the PAYMENT-SIGNATURE header back to the merchant. If the signature field on the voucher is null, that is expected before you sign.
4

Wait for the merchant

You do not submit the batch. Poll get_settlement_status about every 2 seconds if you need to tell the borrower the payment landed. CONFIRMED means the batch entry settled. Available credit updates after that, not at voucher signing.
create_spend_intent and evaluate_spend_policy remain for spend that is not an x402 402. Do not use them to reimplement prepare, and do not call execute_payment on a 402.

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Recoverable stops

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Merchant side of the same payment

The merchant posts the signed envelope to POST /api/v1/facilitator/capture and polls by paymentId. Capture returning 200 means the payment is queued for the next batch, which flushes about every 60 seconds. Fulfillment waits for CONFIRMED. See Merchant integration.

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Next steps

Settlements

Status values and when to release goods.

Errors

Codes you will actually see.