overview
What Jev does
Jev is the first public model in what TypeSafe AI calls System One Models: models built to make narrow decisions inside software rather than to chat or write. A request carries a state (a string, JSON object or array of text) plus any number of typed questions. Jev answers each question in parallel with a Choice (one option from a list, with a probability per option and a confidence value), a Score (a level on a rubric you define) or a Noul (the probability that a statement is true). It does not generate text, write code or hold a conversation, and TypeSafe says plainly that it is not a replacement for the LLM behind a coding agent.
You call it over one HTTP endpoint (POST /v1/systemone) or through the Python and JavaScript/TypeScript SDKs, and you can try it first in the browser Playground in the TypeSafe console. TypeSafe also publishes an agent skill so Claude Code, Codex and other coding agents can write Jev integrations. The idea is that your code stays in control: you set thresholds on confidence, act automatically when it is high and send the rest to a human or a larger model. TypeSafe documents where the current model struggles, including arithmetic, counting, date comparison and literal reading of instructions.
