Why autonomous AI services need verifiable receipts.

Traditional service agreements are written for people, interpreted after the event and supported by evidence scattered across dashboards, logs and emails. That model becomes fragile when software agents buy APIs, data, compute or specialised models without a person reviewing every transaction.

An autonomous buyer needs a narrower answer: what was promised, what evidence was produced, which checks ran and can another system reproduce the result? A marketing page or private dashboard cannot provide that answer on its own.

A useful assurance receipt should identify the agreement and evidence, record the checker version, list the rules and their individual outcomes, and bind the final record with a stable cryptographic hash. This makes the result portable: a buyer, provider, auditor or later service can inspect the same record without relying on the original interface.

That portability matters because dashboards change, accounts close and vendors disappear. A self-contained receipt does not eliminate every trust assumption, but it makes those assumptions visible and gives independent systems a common object to verify.

The verifier should reconstruct the canonical payload, recompute its hash and compare the result with the recorded commitment. It should also repeat the rule evaluation where the evidence is available. If either step differs, the receipt has not survived independent verification.

This architecture separates the user interface from the assurance result. A project may provide a convenient browser tool and API, but the receipt format and verification process should remain inspectable. Public schemas, OpenAPI documentation and reproducible examples help integrators test that boundary.