Why does a 'production-ready' AI agent need a fallback path for when the LLM provider is down or times out?

Unlike a database, an external LLM API call is a third-party dependency you don't control and it WILL occasionally be slow or unavailable — a production feature needs a timeout, a retry with backoff, and ideally a degraded fallback response (or a fallback provider) rather than letting the whole user-facing feature hang or 500 whenever the provider has a bad moment.