One object, round trip, lifecycle preserved.

An integration is not truly interoperable until a single object can make a full round trip through both systems without losing meaning. The object is ingested, validated, normalized, enriched, projected into the partner workflow, and returned with its external identifier intact, provenance preserved, and state transitions mapped explicitly. When the object comes back, deduplication rules must be defined and retest behavior must still work as expected.

The acceptance criterion is simple: the product-native return must be proven. If the partner can receive the object, act on it, send it back, and the original system can recognize, reconcile, and reprocess it correctly, then the integration has survived the lifecycle end to end.