Backend Idempotency

Purpose

Guarantee exactly-once execution for mutating operations using idempotency keys, enabling safe retries without duplicate side effects. Idempotency is the foundation of reliable distributed systems — without it, network retries cause duplicate orders, double charges, and inconsistent state.

Agent Protocol

Trigger

Exact user phrases: "idempotency", "idempotent", "idempotency key", "exactly-once", "retry safety", "deduplication", "duplicate detection", "idempotent endpoint", "safe retry".

Input Context

• Which endpoints need idempotency guarantees.
• Existing data store (Redis, PostgreSQL, DynamoDB).
• Current retry configuration.

Output Artifact

Idempotency key handling design. No file unless requested.