Idempotency

Send an Idempotency-Key header when a producer may repeat the same request after a timeout or network error.

PromptJang scopes the key to the target:

• Same target, key, and payload: returns the original accepted item with idempotent_replay: true.
• Same target and key with a different payload: returns 409 Conflict.
• Different targets may reuse the same key.

An idempotent duplicate creates no new delivery and no new billable usage. Keys may contain 1–255 characters. Use a stable business identifier such as payment-pay_123-succeeded, not a random value generated for each attempt.