cache-engineeringlisted

# Cache Engineering Use only after the active phase identifies a cache-specific decision. Inherit its authority, artifact, review, proof, output, and completion contract; do not select design, diagnosis, implementation, review, or production-action mode. Core invariant: a cache is a bounded copy with explicit authority, key scope, freshness, fill and invalidation ownership, degraded behavior, and a falsifier. Reject a cache whose measured value does not justify that complexity. Load one branch: - whether caching should exist -> [value.md](references/value.md); - value, key, freshness, or invalidation contract -> [contract.md](references/contract.md); - concurrent fill, hot key, outage, or layer-specific behavior -> [runtime.md](references/runtime.md); - migration, rollout, or proof -> [rollout-proof.md](references/rollout-proof.md).