API Contract / Evolution
Kind: tension
Record: tension:api-contract-evolution
Canonical: Schema
"api-contract" (contracts-core layer) is traded against "Evolution" (contracts-core layer) — a principle cannot be scope-separated from a quality, metric, or cost it competes with; resolve by measuring "Evolution" and choosing an explicit operating point.
Listed in Tensions, after Contract-First Design / Iteration Speed and before Service Contract / Distributed Evolution.