Full guide: What is a System One (System 1) model? Decision and extraction models
A System One model is an AI model that returns typed answers and probabilities instead of generated text. It has two classes, decision models and extraction models. Jev, from TypeSafe AI, was the first, announced on 15 September 2026. TypeSafe took the name from Kahneman’s fast System 1 thinking, and its three question types are Choice, Score and Noul. The industry now calls Jev’s class decision models. For the full explanation, including how they differ from LLMs and which models exist, read What is a System One (System 1) model?. Jev’s specs are on the Jev model page. Since 19 October 2026 Cloudflare also calls Clairic a System One model, the first of a second class, extraction models, which return typed values instead of decisions. TypeSafe had not commented on that use of its term as of 19 October 2026.