How to Use Jev: A Practical Guide

Cascade: Jev intent- and complexity-scores each message, pure code handles lookups, specialists take the hard minority. The guide's million-ticket math drops $30,400 to $6,480.

Speculative fan-out. A tenth question costs tokens but almost no time, so ask everything up front — severity, repro steps, refund intent — and let code branch on what mattered.

No. Confidence-gated routing sets one per action, scaled to the cost of being wrong: below 0.5 goes to a human, while moving money needs 0.85 or better.

It is self-run against consensus labels from two frontier models, and cannot-hallucinate means no invalid values — not no wrong ones. Evaluate on your own traffic.

Python 3.10+ with pip install typesafe-sdk or uv add, and JavaScript/TypeScript on Node 20+ with npm install @typesafe-ai/sdk. Both read TYPESAFE_API_KEY from the environment and default to jev-latest. There is also a single endpoint, POST https://api.typesafe.ai/v1/systemone, if you would rather call it directly.

Get one from console.typesafe.ai/settings/keys, though the guide notes early access is waitlisted, or through the Vercel AI Gateway. Either way you export TYPESAFE_API_KEY and the SDKs pick it up. The guide's own caveat still applies: the headline numbers are TypeSafe's, self-run and unreproduced.

Four: it reads literally, so it misses implication; it is weak at counting; it treats dates as text rather than reasoning about them; and accuracy drops as the state fills with unrelated content, which the guide calls context rot. Curating what you send is described as most of the work, and one of the five patterns is a retrieval-then-judge cascade.