01 6 min Updated Sep 19, 2026
What is Jev?
TypeSafe’s first System One model: state + typed questions in → decisions + probabilities out — no chat text.
One sentence
Jev is TypeSafe AI’s first System One model: program state plus typed questions in, typed probabilistic decisions out. It does not chat.
Primary source: Introducing System One Models & Jev (2026-09-15).
Question types
Documented in public Gateway / TypeSafe materials:
- Choice — select from options you defined
- Score — grade against an ordered rubric
- Boolean — probability of true, with confidence metadata
Access timing
Early access / waitlist as of Sep 2026 — always re-check typesafe.ai.