Grammar-Constrained Generation vs. ObjectWeaver: Two Paradigms for Guaranteed JSON
Reliably generating structured JSON from Large Language Models presents a fundamental challenge with two distinct solutions: grammar-constrained generation and LLM orchestration. Grammar-constrained generation (Outlines, Guidance, llama.cpp GBNF, Formatron) forces compliance through inference-time token masking—optimized for simple, flat schemas. ObjectWeaver orchestrates field-level generation with parallel processing, dependency management, and intelligent model routing—designed for complex production schemas where different fields demand different capabilities.
