Most teams that bolt a chat model onto a production workflow hit the same wall within a sprint or two. You ask for JSON, you get JSON wrapped in prose. You ask for a label, you get a label plus an explanation and an invented field name. You ask how confident the model was, and the answer is a confident-sounding sentence rather than a number your code can branch on. Decision AI exists because that failure mode is structural, not a prompt-tuning problem: a text generator optimizes for plausible language, while a decision engine optimizes for a correct, typed answer. For developers, product teams, and ops groups, the distinction changes…