Define expected output structure as a Pydantic model. After each LLM call, parse the response — Pydantic validates types, required fields, and constraints automatically.

Define expected output structure as a Pydantic model. After each LLM call, parse the response — Pydantic validates types, required fields, and constraints automatically. On ValidationError: catch it, format it clearly, send back to the model with a correction instruction (self-healing loop). In a document extraction pipeline: caught 100% of structural errors before they hit downstream systems, eliminating silent data corruption.