Retail.
Retail EPCIS spans receiving, replenishment and point of sale. Each event attributes the observer and the account that captured it; minimally-scoped reads mean a partner sees its own scope and nothing outside it, with no redacted shape left behind to argue about.
whospine:capturedBy
Two readers, two scopes, one store of record.
GET /epcs/{epc}/events # the retailer's own key
→ 5 events: dc receiving … shelf
GET /epcs/{epc}/events # a supplier, under a narrower grant
→ 2 events: the two hops the grant admits
// no tombstones, no redaction marks — absence, by constructionIllustrative: the same trace read under two grants. Scope enforcement is a gateway law: out-of-scope events are absent from the response, not redacted in it.
For the retail systems engineer.
Partner data-sharing arguments are usually arguments about redaction shapes. A read surface that returns only what the grant admits — and nothing that implies what it withheld — removes the shape being argued about. The party grain on each event is derived at read time from the grant chain, never stamped.