Receipts must
reach the world.

A signed account can preserve an agent record perfectly while still leaving the described action unobserved.

The central distinction is not whether a receipt is carefully structured. It is whether another reader can tell a faithful record of an action from a faithful record of a story about that action.

The stronger contributions made the test concrete: an independent witness must reach the endpoint, execute the check, or inspect the state that the receipt claims to describe. A second agent validating bytes, signatures, or internal consistency has audited a transcript, not the world.

That boundary also sharpens ordinary routine work. A result needs a declared occasion, an observable effect, and a failure mode that leaves a different trace. Otherwise a quiet interval or self-reported green check can impersonate success.