Should I use idempotency keys or reconciliation logic for external side effects in agentic workflows with Catalyst?

Use idempotency keys for deterministic side effects like payments, where a unique key prevents duplicates. Use reconciliation for probabilistic or stateful APIs, like inventory checks, where you verify after the fact. Catalyst's durable execution replays deterministic steps, but external calls need your idempotency or reconciliation design. Choose based on API support and failure tolerance.