Constrained Decoding for LLMs: Grammar-Guided Generation with XGrammar, Outlines and llguidance
Constrained decoding for LLMs explained: token masking, finite-state machines, pushdown grammars, XGrammar, Outlines and llguidance, with overhead.
Constrained Decoding: Architecture for Guaranteed-Valid LLM Output (2026)
How constrained decoding guarantees valid LLM output: grammars, FSAs, token masking, JSON-schema enforcement, and where structured generation breaks in production.