also deduplication, exactly once, duplicate requests
An operation that has the same effect whether it runs once or several times. It is what makes retries safe for anything with side effects.
You have done this if
You passed a request ID with every 'create ticket' call so a retried agent step did not open two tickets.
Say it in a review
Every tool call with side effects carries an idempotency key, so a retry can't send the email twice.
On the AI Application map Tools, Enterprise APIs
Read A retried agent job is a second chance to send the same email · Pattern: the outbox for agent actions