Prepare before measured payment
Artifact-backed measured offers inspect immutable artifact metadata and return exact binding terms before money moves. Fixed-price offers do not perform that artifact price read.
One identity to terminal state
A bounded HTTP wait may return an accepted invocation while work continues. Read that invocation until it reaches a terminal state; do not create a new purchase because a connection ended.
- Success becomes visible only after its receipt is sealed.
- Failure after settlement converges to fulfilment, refund, or explicit escalation.
- Cancellation is a request and may be refused or lose a race with completion.