A long-running agent may restart between stages that create external records. Which two design choices support safe continuation? Select 2 answers.

1. Keep all completion state only in the process that may restart.
2. Use idempotent operations or stable deduplication keys for retryable side effects.
3. Regenerate unrelated record IDs on every retry without checking prior completion.
4. Assume every network timeout proves the external write failed.
5. Persist completed-stage identifiers and the current task state durably.