Status: IN
Both deterministic identity derivation (DM conversations from sorted user pairs, threads from first message ID) and idempotency enforcement (key-only matching ignoring payload) share a pattern of deriving operation identity from minimal existing data without examining payloads. This approach eliminates coordination overhead for identity creation, but in the idempotency case introduces silent-mismatch risk when distinct operations share a key.
Deterministic IDs and payload-ignoring idempotency keys both trade validation for simplicity — same tradeoff, different domains
Depends on (SL): deterministic-ids-eliminate-coordination, idempotency-keys-ignore-payload-content