A remediation event may be delivered twice. The action opens a support case and changes a resource setting. How should the runbook handle repeated delivery?

1. Assume event delivery is universally exactly once and omit all duplicate handling.
2. Mark remediation complete before any action succeeds.
3. Use stable incident identity and idempotent or conditional actions that recognize already-applied work.
4. Assign a new incident ID on every retry and open another case unconditionally.