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JEV: How It Works and What You Can Build

Riley Brown on a decision model that cannot write: a model router, Choice, Score, and Noul, then speed, cost, and where to get access.

Category
Guides & Articles
Format
Video
Published by
Community
Author
Riley Brown
Added
2026-09-28
Last verified
2026-09-28

Highlights

  • The description frames Jev as a decision model that cannot write, but can route, classify, and filter.
  • Chapters: model router at 2:08, what Jev is at 3:56, Choice, Score, and Noul at 5:19.
  • Later chapters cover structured output, speed, and cost, then monitoring, context window, and how to get access.

Watch out

Chapter times are from the video description. This entry does not restate any benchmark numbers from the talk.

Reactions & coverage

Posts, threads, and videos about this entry from around the web.

YouTube: Riley Brown on a model that cannot write: routing, Choice, Score, Noul, then cost and access.

Hacker News: Vercel on using Jev for defined decisions and GPT-6 Astra when the job also has to write or use tools.

flashbrew4 pointsTypeSafe AI Jev vs. GPT-6 AstraRead the thread on Hacker News

X: How the agent stack moved in Jev's first three days

YouTube: LangChain walks through Jev as a System 1 layer in an agent loop: model routing, auto mode for risky tools, and judged evals.

Related terms

Glossary definitions related to this entry.

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A Krish Naik explainer on whether Jev replaces LLMs and where decision models fit next to generative models.
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From the community

Posts from builders shipping with Jev right now.

Follow @typesafeai

Foreman keeps coding agents on task

Unclutter: an ad and slop blocker that runs on Jev

An open-source BS meter for debates and investor calls

🚨 Open Source Jev BS meter you can use this to analyze any debate / investor call / interview / sales pitch / podcast video fact check live , for example this dario interview cost 60 Jev calls / 111K tokens / $0.0047 github.com/ChetasLua/jevm…

Chetaslua
Chetaslua
@chetaslua

🚨 I gave the Trump vs Kamala debate a live BS meter using Jev every sentence, both candidates, 5 yes/no questions each 1,191 Jev calls / 1.18M tokens / 415 ms median total cost : $0.0497 same questions for both, clips picked by one fixed rule, not a fact-check

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A Jev-shaped model on Cerebras and Qwen

Built an alternative version of @typesafeai but on @cerebras with Qwen 3.8 27b. Similar quality, similar performance, but vastly different cost. TypeSafe was way cheaper, and did beat Qwen on performance. Closest we can get using LLMs I think. Source: github.com/iammrduncan/ty…

Diogo Almeida
Diogo Almeida
TypeSafe AI
@CompleteSkeptic

After co-inventing ChatGPT, I kept asking myself: why have superhuman chat models not led to AGI? I’ve spent the last 2 years in stealth building a new way to train models (RLCD), and a new type of frontier AI model that we are releasing today: Jev • 20-200x faster • 40-400x

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Jev benchmarked on two public safety corpora

1/ Benchmarked TypeSafe's Jev on two public safety corpora. It doesn't generate text, it returns calibrated probabilities you threshold in code. 96.5% on prompt injection, all 662 messages in deepset/prompt-injections. No tuning. 325ms p50.

Terminal dashboard showing 96.5% accuracy on prompt injection and 89.0% pairwise on vulnerable code, with a context ablation and calibration plot.
Diogo Almeida
Diogo Almeida
TypeSafe AI
@CompleteSkeptic

After co-inventing ChatGPT, I kept asking myself: why have superhuman chat models not led to AGI? I’ve spent the last 2 years in stealth building a new way to train models (RLCD), and a new type of frontier AI model that we are releasing today: Jev • 20-200x faster • 40-400x

Reply

An open 151M-parameter decision engine

TypeSafe AI came out of stealth with Jev, and access is behind a waitlist. I built an open source version Verdict (Open-jev) you can run right now in a browser tab: And its a real post trained model..(link in comments) It is a post trained 151M parameters model. ModernBERT-base Show more

Image
Diogo Almeida
Diogo Almeida
TypeSafe AI
@CompleteSkeptic

After co-inventing ChatGPT, I kept asking myself: why have superhuman chat models not led to AGI? I’ve spent the last 2 years in stealth building a new way to train models (RLCD), and a new type of frontier AI model that we are releasing today: Jev • 20-200x faster • 40-400x

Reply