Resolve every commercial role before authorization
Agentic payments in a marketplace should identify the platform, seller, merchant of record, payment recipient, fulfiller, and support owner. Those roles may collapse into one organization or span several. The mandate must scope the party and risk the principal actually approved, not merely the marketplace domain.
Product ranking, sponsored placement, seller reputation, and platform guarantees are decision inputs. Preserve why the agent selected a seller and whether the platform or seller made each material claim.
| Role | Question | Evidence |
|---|---|---|
| Platform | Who provides discovery and checkout? | Platform and order identifiers |
| Seller | Who offers the item and terms? | Seller identity and listing version |
| Merchant of record | Who owns the charge and tax obligation? | Receipt and statement descriptor |
| Fulfiller | Who delivers the product? | Shipment or service event |
| Support owner | Who handles refund or dispute? | Policy and case reference |
Bind authority to seller-level order components
A multi-seller cart may create separate orders, captures, shipments, and refunds. Authorization should preserve seller, item, quantity, price, fee, tax, delivery, and cancellation terms for each component while enforcing an aggregate budget for the principal's task.
If one seller becomes unavailable, do not silently substitute another because the product appears equivalent. Compare merchant scope, total cost, delivery, warranty, and return policy to the mandate and ask for step-up when a hard constraint changes.
- Carry platform and seller identifiers into the payment evidence.
- Use idempotency at both cart and seller-order levels.
- Reconcile partial capture, fulfillment, return, and refund independently.
- Explain sponsored or platform-preferred choices to the principal.
Keep payment credentials scoped to the real recipient
The platform may tokenize or route credentials while sellers remain invisible to the rail. Policy still needs the commercial seller and purpose. Conversely, a split-payment system may create multiple recipients for one visible checkout. The credential and mandate model should reflect the actual funds flow without forcing the model runtime to handle raw account details.
Marketplace risk controls should not be treated as proof of user authorization. Seller screening, fraud scoring, and agent authority answer different questions and should leave separate evidence.
Operate partial outcomes without losing the task view
One seller may fulfill while another cancels. A partial refund may arrive before a return is received. Join each event to the seller-level order and roll it up to the principal's original task so the agent can present a coherent outcome.
Dispute and support workflows should expose the responsible party and available remedy. The agent needs new authority before accepting store credit, replacement terms, restocking fees, or a refund destination different from the original payment path.
Marketplace checkout is one interface over several accountability relationships; the payment record must not flatten them away.
Source discipline
Primary sources
Product status and protocol behavior are checked against maintainer documentation. Company sources establish what their organizations publish; they do not independently prove adoption or performance.