Using JSON Schema to generate JSON objects with LLMs

We present a novel application of JSON Schema: using it as a real-time contract for guiding Large Language Model (LLM) generation rather than merely for post-hoc validation. Our implementation achieves 100% schema compliance in production deployments across healthcare, autonomous agents, and data extraction. This work expands JSON Schema’s utility beyond validation, positioning it as a bidirectional contract that controls both validation and generation, and suggests opportunities for formalizing generation-time usage patterns within the JSON Schema ecosystem.