An agent buys from a retailer
Understand the buyer, merchant and payment-provider handoffs before opening a checkout to outside agents.
Evidence, not endorsement
A research and planning tool, not a vendor certification. Sources describe specific products, not every service offered by a company. Unknown means not established by the sources reviewed, not unsupported. grug402 sandbox tests do not test these vendors. Operational owners are suggested team contacts, not legal liability assignments.
Editorial review: 2026-10-08. Evidence older than 90 days needs rechecking; source check dates are not release dates.
Illustrative participants, not integrations
The sequence below is a hypothetical role walkthrough. Named examples do not imply a working connection.
Discovery
An agent finds products, price, stock and delivery terms. Example roles: Muse or Instinct on the buyer side; a retailer such as Walmart on the seller side. This is a hypothetical pairing, not a documented integration.
Suggested operational owner: Catalog and commerce engineering.
Authorization
The shopper sets a budget, recipient, item constraints and approval policy. A logged-in browser alone is not evidence of a payment mandate.
Suggested operational owner: Agent product and identity/security.
Payment
The merchant and payment provider agree a checkout contract and accepted payment method. Do not assume retail checkout uses x402 merely because the buyer is an agent.
Suggested operational owner: Payments engineering.
Delivery
Create and reconcile the order, inventory reservation, shipping commitment and receipt after the agreed payment milestone.
Suggested operational owner: Order and fulfillment operations.
Failure & recovery
Reconcile uncertain payment state before retrying. Define support, cancellation and refund procedures with the actual providers.
Suggested operational owner: Customer operations and payments.
Relevant sandbox tests — not vendor results
These are controlled grug402 scenarios. A passing sandbox request does not certify a company, integration, checkout or refund process.
- P1: A payment that completes — Establish a baseline before diagnosing failure cases. Suggested owner: Payments engineering.
- P1: Keep a spend within its limit — A quoted price can exceed the buyer's permitted per-call spend. Suggested owner: Agent product and security.
- P1: Check the intended recipient — A valid-looking request may name the wrong receiving address. Suggested owner: Payments engineering.
- P1: Retry without a duplicate charge — Lost responses should not cause the same purchase intent to be paid again. Suggested owner: Application engineering.
- P1: Handle paid-but-not-delivered — Settlement can succeed while the application fails to deliver. Suggested owner: Payments and customer operations.
Coverage limits
These are HTTP payment analogues, not tests of a retailer's checkout, tax, inventory, shipment, refunds or consumer-protection process.