LangGraph Error Handling Patterns for Production AI Agents

You have a document processing pipeline. It ingests contracts, extracts key clauses, validates them against policy, and generates a summary. Monday morning it processes 200 documents without a hiccup. Tuesday at 2 AM, Anthropic’s API returns a 429, the extraction node throws, and the entire pipeline stops. Not just the one document — the whole batch. Your on-call engineer spends 45 minutes figuring out it was a transient rate limit that would have resolved itself with a 2-second backoff. The fix