Valiron Payment Interceptor

Add a trust gate in front of outgoing agent payments.

Runtime requirements

Declare and validate runtime prerequisites before enabling the interceptor:

• Node.js runtime compatible with your app and @valiron/sdk.
• Installed dependencies:
  • @valiron/sdk
  • Your payment rail package(s) (x402 or equivalent) used by the host app.
• Configuration/credentials (via secret manager or env vars):
  • VALIRON_API_KEY (optional today; reserved for authenticated deployments)
  • VALIRON_BASE_URL (if using non-default endpoint)
  • VALIRON_TIMEOUT_MS (optional, with safe default)
• Policy/config inputs:
  • Decision policy JSON (route-to-action matrix)
  • Spend limit defaults and per-route overrides

Fail startup (or fail closed for payment endpoints) when required policy/config inputs are missing. If your deployment enforces SDK auth, treat VALIRON_API_KEY as required.

Workflow

1. Extract counterparty identity from the payment request.
   • Prefer counterpartyAgentId.
   • Support wallet fallback with getWalletProfile(wallet).
2. Evaluate trust with Valiron.
   • Fast path: checkAgent(agentId).
   • Full path: getAgentProfile(agentId) when you need reasons/signals, pricing, or audit details.
3. Apply deterministic decision policy from references/decision-policy.md.
4. Enforce spend controls from references/spend-controls.md.
5. If allowed, continue to payment initiation (x402 challenge creation or equivalent flow).
6. If blocked/restricted, return explicit denial/degrade reason.
7. Log outcome using references/audit-events.md.

Decision model

Map route decisions to payment actions:

• prod: allow payment under normal limits.
• prod_throttled: allow with reduced caps/rate limits.
• sandbox: allow only test/sandbox payment rail (or deny prod transfer).
• sandbox_only: deny outgoing payment.

Never authorize payment using free-form model output alone.

x402-specific sequencing

For x402-protected purchases or settlement-like flows:

1. Trust-check counterparty identity.
2. Evaluate route + spend policy.
3. If denied, abort before creating payment commitment.
4. If allowed, generate/send x402 payment payload.
5. Record authorization decision + amount + result.

Outage and fallback

Use endpoint-class fallback from references/fallback-modes.md:

• High-risk payment actions: fail-closed.
• Low-risk/test actions: optional fail-open-guarded with strict caps.

Keep fallback mode explicit and versioned.

Use bundled resources

• Runtime + credential checklist: references/runtime-requirements.md
• Decision matrix: references/decision-policy.md
• Spend/risk controls: references/spend-controls.md
• Fallback guidance: references/fallback-modes.md
• Audit schema: references/audit-events.md
• Error handling: references/error-handling.md
• Interceptor template: assets/payment-interceptor.ts
• Policy validator: scripts/validate-payment-policy.mjs