Idempotency

Idempotency-Key is mandatory on mandate-consume, recommended on process-biovital-transaction, and does not apply to mandate-check, which moves nothing.

The key

• 8–200 characters, chosen by you, unique per intended operation.
• The same key replayed returns the original consumption with idempotent_replay: true and debits exactly once.
• A different key for the same intent is a second operation. Derive the key from your own action reference.

-H "Idempotency-Key: booking-88213-attempt-1"

Where else it applies

Strongly recommended on process-biovital-transaction, where a replay returns the original body with the response header Idempotency-Status: replayed.

Where it does not apply

It does not apply to mandate-check. Check does not move anything, so there is nothing to deduplicate. Earlier documentation claimed the opposite; that was the single most dangerous error in it. See mandates/check.

Why the ledger is append-only

Consumptions are rows, not a decremented balance column. A counter loses the reason, and the reason is what an audit needs: who acted, under which mandate, against which action reference, at what time.