# Contracts use one schema with layer profiles

Authored data product contracts use one universal schema with layer-specific validation profiles rather than four separate schemas for raw, staging, curated, and service products. This keeps tooling, CI, runtime projection, and agent parsing consistent. Layer profiles still allow each layer to require different guarantees, such as provenance and retention for raw, schema and caveats for staging, semantics and SLOs for curated, and interface compatibility for service.