Jev Companion

Jev Companion is an independent, unofficial guide, setup assistant and console for Jev, TypeSafe AI's System One decision model. It is not affiliated with, endorsed by, or sponsored by TypeSafe AI. Jev is not a chatbot. You send it state plus typed questions, and it returns typed values, full probability distributions, and a confidence you can branch on. This app takes you from never having heard of it to making your own calls. LEARN • What Jev is, and where it fits next to a large language model • Choice, Score and Noul — the core decision types; experimental Box in Image Lab • Confidence and thresholds: the second decision axis • Patterns that work: fan-out, confidence-gated routing, composite scoring, intent routing, cascades • The nine documented failure modes, and how to design around them SET UP • Get an API key and keep it out of your code • First calls in raw HTTP, Python and TypeScript • Choose jev-latest, jev-preview, or a pinned version; inspect the version returned in history • Teach Claude Code, Codex or Cursor to write correct Jev code USE • A live console: compose a state and any number of questions, send, and read typed answers with confidence bands and probabilities • Five ready templates: support triage, refund guardrail, content moderation, bug severity, citation check • Copyable raw request and response JSON, session history, and answer validation • Experimental Image Lab with local preparation, per-request opt-in and presence-gated Box overlays • Per-request experimental long context, with context budgets and encoded request size • Comparison Lab with clearly simulated fixtures and local JSON export • A public demo mode with simulated responses, so you can explore the complete console workflow before you have a key PRIVATE BY DESIGN • No account, no analytics, no advertising, no server of ours • Your key is stored in the device Keychain • Requests go straight from your device to api.typesafe.ai, under your own account The eighteen official cookbooks, the SDK references, the ecosystem map and the honest failure modes are all here, offline, in one place. Jev Companion is an independent app by 1337-Software. It is not affiliated with, endorsed by, or sponsored by TypeSafe AI. Jev and TypeSafe are the property of their respective owners. Pricing, rate limits, latency and model IDs change without notice; verify them at docs.typesafe.ai/models.