AI Agents in Production: Error Handling, Fallbacks, and Cost Control

I watched an LLM pipeline burn $400 in 90 minutes once. Not because the model was expensive, but because a single unhandled 429 rate-limit error triggered an infinite retry loop against GPT-4. No fallback. No circuit breaker. No cost alert. Just a runaway process that kept hammering the API until the billing dashboard lit up. That was early in my job board platform work, where I was processing 10,000+ job listings daily through an LLM scoring pipeline. The system worked great in testing. In pro...