Ontario Protocol.
x402 pre-payment decision playbook

Prevent paid-but-denied failures for security reviewers

The worst payment UX is a settlement followed by no usable service response. This playbook maps the decision to observable Ontario evidence so an agent can fail closed before payment.

Search Console priority Prevent paid-denied security teams No-payment first
Decision question: Can security reviewers rely on this x402 endpoint without trust language that outruns observable evidence?

Only after security reviewers can inspect preflight result, endpoint readiness, report history, payment challenge consistency, and fallback policy. If the evidence is missing, stale, or contradictory, the agent should fail closed.

Required evidence

  • Confirm the endpoint maps to a real payment resource for reviewers checking payment, metadata, and replay boundaries.
  • Require preflight result, endpoint readiness, report history, payment challenge consistency, and fallback policy.
  • Reject when there is stale report, mismatch between manifest and challenge, missing response schema, or policy review-required.
  • Link the final decision to a public report, manifest, benchmark row, or policy outcome.

Reject conditions

Reject or send to human review when there is stale report, mismatch between manifest and challenge, missing response schema, or policy review-required.

Do not let a positive-looking badge or directory row override a stale or contradictory live check.

Agent workflow

  1. Start with the no-payment evidence path.
  2. Run the Ontario verifier or policy endpoint shown below.
  3. Compare live endpoint behavior against manifest and discovery metadata.
  4. Store the report_id or policy decision with the agent's payment log.
  5. Send the payment only when the agent's own policy allows it.

Command or probe

curl -X POST https://ontarioprotocol.com/api/agent/can-pay \
  -H "Content-Type: application/json" \
  -d '{"target_url":"https://example.com/api/paid-endpoint","fail_closed":true}'

Primary Ontario surface: /api/agent/can-pay

Sourceability note

Search Console showed early impressions for payment attack/preflight proof.

KPI: more report and methodology page inspections.

Trust boundary

Ontario Protocol provides readiness and trust signals based on observable endpoint behavior, manifest metadata, payment challenge behavior, report history, and public evidence. It does not guarantee endpoint safety, service quality, financial outcome, or future behavior.

Read payment attack preflight proof Run verifier Browse discovery Read trust boundary