A worked example of SPEC.md §5.8 (purchasing) and §5.9 (fulfillment).
A parent or organization tops up a student's spendable balance, the student spends part of it on something from a small menu, and gets a signed receipt to present at pickup. Every step below is a real call to this domain's own server — the balance and the receipts are genuine credentials, not a mockup.
POST /atlas/asset/purchase has no idea it's selling food — a class becomes
purchasable the moment a catalog entry declares its own price, and the identical
endpoint would sell an item in a spatial world's shop the same way, with no code of
its own for either case. This page is one worked example of a generic mechanism, not
a cafeteria-specific feature.
Nothing on this page is stored in a database anywhere beyond the credentials themselves. The balance is bound to the student's own key — it can be spent, never gifted or traded away — and a receipt, once fulfilled, is revoked the same one-sided way a redeemed credential is: the operator's own signature is enough, nothing further is required from the student's side. Back to the plaza · Credential demo.