Structured outputs

Structured Outputs enforce a predefined schema (e.g., JSON, XML) on Large Language Model (LLM) responses, guaranteeing machine-readable, consistent data for reliable system integration.

This technology eliminates the unpredictability of free-form LLM text. Structured Outputs leverage techniques like constrained decoding and Context-Free Grammars (CFG) to strictly limit the model’s token generation, ensuring the output conforms to a user-defined JSON Schema or Pydantic model. This capability is mission-critical for production systems: it ensures 100% format reliability (a massive leap from the ~35% reliability of older 'JSON mode'). Use it for seamless data extraction, reliable function calling, and direct API integration, turning erratic text into clean, verifiable data for your downstream applications.

https://humanloop.com/blog/structured-outputs-everything-you-should-know