This is the full index of everything Jev: 552 entries for TypeSafe AI's flagship System One model, from official documentation, SDKs, and cookbooks to community-built clients, MCP servers, agent tools, and write-ups. Every entry is tagged by category, format, and topic, and sorted newest first.
Filter by category or tag, or search titles, descriptions, authors, and repos. Open any card for its detail page — most entries carry a verified deep dive with highlights, caveats, and a quickstart snippet.
Last updated . Entries are added as they appear and re-checked when they are touched.
9 ways into the ecosystem. Each category page leads with its own shortlist of starting points.
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Showing 1–48 of 552 resources
feder-cr/jevPython
ollaya-dev/ollayaRust
Rizzo-AI-Academy/rizzo-flowPython
receptron/layaTypeScript
Mushroom-Systems/lichenPython
khimaros/verdictPython
Liuziyu77/ValenPython
dzhng/jevgrepTypeScript
jerryjliu/docjevPython
itsmostafa/system-one-connectorGo
FrancoisChastel/jev-codeTypeScript
AgriciDaniel/gatekeeperPython
andududu/jeviewJavaScript
parth-kp/jev-mail-classifierPython
klauswg/jev-guardJavaklauswg/jev-suiteJava
bytelabs-oss/clash-jevPython
rmalde/minecraft-agentJavaScript
dchristopoulos/jev-aitaPython
AnthusAI/Jev-CalibrationPython
deepanwadhwa/OpenDecisionPython
chaitin/DecisPython
nokia-applied-research/AnyJevPython
Yinsongxu/LLM2JevPython
togethercomputer/tev1Python
openlayer-ai/jevalsPython
ThinkFlowLab/system1-agentsPythonHand-picked entries the maintainers recommend first, from official primitives to community tools.
Hawxy/TypeSafeAI.NetC#
tryAGI/TypeSafeAIC#The latest additions to the directory, newest first.
Walkthroughs, tests, and demos from the community.
YouTube: KodeKloud's three-minute primer: what a System One model decides, and why it answers in milliseconds.
YouTube: Caleb Writes Code explains what Jev is and how to call it, in seven minutes.
YouTube: Greg Isenberg and Ryan Vogel on the businesses Jev unlocks, and a path in through the Vercel AI Gateway.
YouTube: CJ from Syntax demos browser use, classification, code review, a model router, and a chat bot with no LLM.
YouTube: Ryan Vogel runs Jev on 100 and then 1,000 emails: category, priority, spam, and reply predictions.
YouTube: AICodeKing tests support routing, refund detection, prompt-injection resistance, and browser automation.
Threads from Reddit and Hacker News about building with Jev.
Reddit: Matthew Berman's video on Jev, at roughly 290K views.
Hacker News: Jev implemented in 25 lines of Python
bashbjorn400 points · 128 commentsJev in 25 Lines of PythonRead the thread on Hacker NewsHacker News: Show HN: a GIF decider that lets Jev pick the reaction.
arminn2 pointsShow HN: I Built a GIF Decider with JevRead the thread on Hacker NewsHacker News: Show HN: a mouse colony where each next move is Jev or a fixed rule.
1 pointShow HN: Jev-mice – mouse colony simulation using Jev and deterministic engineRead the thread on Hacker NewsHacker News: Does OpenAI fast-follow Jev?
JohnBerryman302 points · 213 commentsOpenAI is well positioned to fast-follow JevRead the thread on Hacker NewsHacker News: Show HN: JevBench, a reproducible benchmark for typed decision models
florianstandhar123 points · 34 commentsShow HN: JevBench, a reproducible benchmark for typed decision modelsRead the thread on Hacker NewsEvery entry is hand-picked against the same bar, whether it comes from TypeSafe or the community.
Spam, affiliate links, and thin AI-generated content are rejected. New entries are expected to ship with a deep dive: two to five highlights, caveats, a quickstart snippet where one helps, and a verification date. Star counts are refreshed when an entry is touched.
Short answers about Jev and how this directory works.
Jev is TypeSafe AI's first System One model. It takes a state plus typed questions and returns one structured answer per question — a choice, an ordered score, or the probability of yes — with calibrated confidence on Choice and Score answers, so code can branch on the result without parsing generated text.
They are the three question primitives. Choice picks one of up to 255 options, Score rates on 2 to 10 ordered levels, and Noul answers yes or no. Choice and Score answers carry a confidence between 0 and 1; a Noul answer is the probability of yes.
TypeSafe maintains official JavaScript/TypeScript and Python SDKs plus a Python adapter. The community has built clients for Go, .NET, PHP, Laravel, Rust, Elixir, Ruby, and Scala, along with framework integrations such as DSPy, LlamaIndex, and Home Assistant. All of them are listed in the Repos & SDKs category.
The directory is free to browse: every entry is hand-picked, and spam, affiliate links, and sign-up walls are rejected. JevDirectory.org is community-run and not affiliated with TypeSafe AI — Jev and System One are TypeSafe AI trademarks.
Entries are added as new resources appear and re-checked when they are touched. The directory currently holds 552 entries from 78 source sites, last updated Sep 28, 2026.
Most entries include a deep dive: two to five highlight bullets someone would only know from using the resource, a caveats note about limits and requirements, an optional quickstart snippet, and the date the link was last checked. 552 of the 552 entries carry one today.
For the canonical details, read the official TypeSafe docs and the API reference.
Posts from builders shipping with Jev right now.
Classifying 1,500 real emails
this model is actually insane at email classification i tested it on 1500 of my own emails to see how well it works and I am blown away
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
Fast browser use with Stagehand
we built blazing fast computer/browser use with Jev + @Stagehanddev. this task cost $0.001 and executed at near instant speed (in a remote browser btw) the loop: observe the page, send a11y tree as state + actions as questions, Jev decides the next action, then Stagehand Show more
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
LLM-as-a-judge, sped up
Jev has spoken. It picked which model is AGI. 20–200x faster. 40–400x cheaper. This could make things like LLM-as-a-judge insanely fast and nearly free. (I tried a bunch of prompts and still didn’t burn through $0.10.)
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
Instant compaction with Jev
found the perfect use case for @typesafeai Jev: instant compaction in 2026, why is compaction still a summarization prompt? Jev can make it instant by scoring every tool call and dropping what’s irrelevant
A Claude session from 1M to 86K tokens
This is actually insane. This uses @typesafeai Jev model, as a plugin in Claude to review all the un-nesseasary tool calls, and it takes 1s to run! Like, literally, 1 second to take my Claude session from nearly 1M to ... 86K tokens! 😮 Ask your claude to install it and be Show more
found the perfect use case for @typesafeai Jev: instant compaction in 2026, why is compaction still a summarization prompt? Jev can make it instant by scoring every tool call and dropping what’s irrelevant
Vercel's fx safety reviewer, 18x faster
We're seeing extraordinary results from @typesafeai. Default mode in 𝚏𝚡 is auto, with a safety reviewer analyzing every command. That reviewer runs on GPT Luna today. Jev is up to 18x faster (p95) *and* more accurate. It's coming to @vercel AI Gateway and likely new default.
We benchmarked fx auto mode (safety) classifier with @typesafeai's Jev. tl;dr: ~5-18x faster and more accurate than 𝚐𝚙𝚝-𝟻.𝟼-𝚕𝚞𝚗𝚊, our current top choice
