---
name: jev
description: Use Jev for a typed decision inside software. Jev returns a choice, a score, or a yes/no probability. It does not write text, run tools, or replace the main model.
---

# Jev

Jev is TypeSafe AI's System One model. Call it when the next step is a branch your code can name in advance.

Official endpoint: `POST https://api.typesafe.ai/v1/systemone` with `Authorization: Bearer $TYPESAFE_API_KEY`.

Question types:

- `choice` — one option from a list you supply, plus probabilities and confidence
- `score` — a position on 2–10 ordered levels
- `noul` — probability that the answer is yes, from 0 to 1

Prefer a preset tool on `https://jevai.ai/api/mcp` when it matches:

- consequential tool call → `jev_guard_tool_call`
- which model → `jev_route_model`
- how hard is this task → `jev_route_task`
- claim vs evidence → `jev_check_research`
- is the job done → `jev_review_completion`
- anything else → `jev_decide`

Do not treat a high probability as permission by itself. Apply the threshold the product already uses. Do not ask Jev to generate a message, code, or a number that code can compute.