PAT 02
IMPLEMENTATION PATTERN
Idempotent action queue
Retries and duplicate triggers can repeat email, payment, publication, or record updates.
An AI-assisted decision may cause an external or irreversible action.
REQUIRED CONTRACT
Keep these visible.
- 01Stable operation key
- 02Visible state machine
- 03Retry policy
- 04Manual reconciliation
AVOID
Do not hide the failure.
- Direct model side effects
- Blind retries
- Hidden partial state
- Unowned dead letters
Prove the boundary.
Send the same operation before, during, and after completion. Prove one action occurs and every duplicate is visible.