Suppose a research agent needs to buy access to a specialist dataset. It finds a supplier and prepares an order. Before money moves, the system must establish that the dataset, supplier, terms, and total cost fit the purchaser's instructions.
Record the purchase limits
Give the agent a structured purchasing brief. For this example, it should identify the required dataset and permitted use, approved suppliers, maximum total cost, currency, expiry, and whether recurring charges are allowed.
The brief should also state delivery requirements and relevant data restrictions. A dataset that arrives in an unusable format or under unsuitable licence terms does not satisfy the request simply because payment succeeded.
The agent can compare offers and propose an order. A separate policy component checks the proposal against recorded limits and sends unresolved cases to an authorised person. Keep the brief version and selected quote with the order so later changes cannot silently alter what was approved.
Bind approval to the action
Present the reviewer with the supplier, item, terms, total amount including fees, and any continuing permission. Approval needs to refer to the exact order the execution service will submit.
Revalidate relevant limits at execution. A quote may expire, a price may change, or another purchase may consume the remaining budget. Reserve budget consistently across concurrent orders so individually acceptable purchases cannot exceed the total.
Use a narrow purchase tool backed by restricted credentials. The model should not receive an unrestricted payment credential. Enforce supplier, operation, value, and time limits outside the prompt, and define how to revoke access.
Track payment and delivery separately
Assign a stable order identifier before submission. Record the provider's request reference and use its idempotency mechanism where supported. If submission times out, query the existing order or payment before deciding to retry.
For the dataset purchase, track at least these states:
- Proposed: a candidate matches the stated need.
- Authorised: the required policy and human decisions are recorded.
- Submitted: the request has been sent, possibly with an uncertain result.
- Payment confirmed: the payment provider reports the required status.
- Fulfilled: access works and the delivered dataset meets the agreed checks.
- Exception: a pending payment, failed delivery, refund, or dispute needs reconciliation.
Define permitted transitions and the evidence for each. A payment confirmation must not automatically mark the dataset as delivered. An ambiguous submission must not silently become a fresh order.
Apply additional controls for blockchain payment
If the supplier accepts an on-chain payment, bind approval to the network, asset, destination, amount, and exact contract operation. Decode the transaction for review and identify token allowances or other permissions that survive the purchase.
Smart-contract accounts can put validation into the account's execution path. For example, ERC-4337 defines account validation for user operations. The purchasing restrictions still depend on the account implementation and configured policy; the standard does not supply a complete procurement policy.
Check trusted addresses, token units, fees, and any upgradeable contract dependencies. Simulate the proposed transaction where supported, while recognising that state can change before inclusion. Simulation cannot establish that an off-chain supplier will deliver the dataset.
Reconciliation must account for pending, replaced, and reorganised transactions under the chosen network's confirmation policy. Record the transaction reference alongside the commercial order so the two can be investigated together.
Prove the complete purchase path
Begin with a known supplier, a bounded purchase, and a result the system can verify. Exercise the flow using fixtures or an appropriate test environment before granting limited real purchasing access.
Test expired quotes, changed prices, concurrent requests, duplicate submissions, payment timeouts, failed delivery, and refunds. The operator needs a way to inspect an order, stop further spending, and resolve an exception without losing its history.
Keep a record connecting the purchasing brief, selected offer, approvals, submitted request, payment result, and delivery checks. The acceptance decision should cover the entire sequence, including recovery from uncertain outcomes. Contractual and jurisdictional requirements must also be established for the actual engagement; successful execution alone does not establish authority to purchase.