Package Contract. A declared file set, metadata shape, manifest boundary, validation command, and review expectation for a reusable unit of canon or publication work. A package contract turns a folder from an informal collection of files into an inspectable architectural surface: reviewers can know what must exist, what owns the truth, which graph edges must resolve, and which generated artifacts are merely derived.
When a package drives execution, its contract should expose or generate a typed intermediate model so validators and executors inspect the same structured facts.