Artifact Contract. A maintained specification for a generated output's schema, required surfaces, stability rules, validation command, and consumer boundary. An artifact contract lets a projection or Observation Plane artifact be useful without becoming a second source of record: it defines what the generated artifact must contain, how it is checked, and what it is not allowed to decide. For evidence, release, package, or deployment artifacts, the contract should also name the required artifact provenance.
A generated artifact that becomes executable input should have a typed intermediate model, not only prose describing its expected shape.