Guideyoutube.com/@codebasics
JEV explained in 17 minutes with code
codebasics explains Jev with runnable code.
Updated Oct 3, 2026
Projects, posts and guides about Jev, the System One model from TypeSafe AI. Each entry links to its source and shows the cost and speed its author reported.

Diogo Almeida
@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 cheaper (w/ output tokens free) • Frontier composable intelligence optimized for decisions AFAICT the shortest path to AI-based economic revolution
Guideyoutube.com/@codebasics
codebasics explains Jev with runnable code.
Guideyoutube.com/@LearnwithWhiteboard
Learn with Whiteboard on how Jev works, whether it replaces LLMs, and Jev against LLMs.
Guideyoutube.com/@JulianGoldieSEO
Julian Goldie runs through more than a hundred Jev use cases.
Harry Tandy
@HarryTandy
TypeSafe founder Diogo Almeida: "I want to automate the easy work before the hard work" In this 2-hour interview, he explains how Jev uses choices, scores, and yes/no probabilities to route work inside agent loops The guide below has 3 builds: a skill router, a codebase linter, and a retrieval reranker Watch the interview, then copy the builds below
Guidex.com
In a two-hour interview, TypeSafe founder Diogo Almeida explains how Jev uses choices, scores and yes-or-no probabilities to route an agent.
Ricky Grannis-Vu
@RickyGrannisVu
We rewrote the oldest primitive in programming. The if statement takes a sentence now, and Jev decides. That nested boolean mess eleven rules deep, four AND/ORs, one comment nobody understands anymore? Replace all of it with "if this expense is allowed under the expense policy." Judgment Mode, live now.
Guidex.com
Ricky Grannis-Vu on replacing deeply nested boolean expressions with one natural-language sentence for Jev to decide.
Ricky Grannis-Vu
@RickyGrannisVu
Jev gives you a probability. You set two lines on it: above the top one it's a yes, below the bottom one it's a no, anything in the gap runs a third branch. It's just a normal branch, so you can handle uncertainty flexibly.
Guidex.com
Jev outputs a probability, two thresholds split the answer into yes, no and a third branch between them.
saturn
@SatOnchain
this paper is f*cking gold. someone made handbook on "how jev can be used as classifiers for evals on scale" anyone who solve this has chance to make millions. Bookmark and read full handbook.
Guidex.com
SatOnchain shares a handbook on using Jev as a classifier for large-scale evals.
st1ne
@SolSt1ne
Jev Founder, Diogo Almeida, just released an independent working note on building a Jev harness for coding agents Not affiliated with the Jev team, just a builder mapping the loop Section 1 - the split: why harnesses already make these calls, just badly, with regex parsing prose replies Section 2 - five calls to move: files, model, safety, done, context, each one a typed Score, Choice or Noul instead of free text Section 3 - what it saves: ~400x cheaper per decision vs a cached frontier model, 0.2s median per call vs seconds of LLM latency $605 per 1,000 decisions on cold frontier calls down to $0.17 on Jev Bookmark it and read it tonight Then go rebuild your own agent loop
Guidex.com
An independent working note on building a Jev harness for coding agents.

VIctor Janni
@VictorJanni
If you liked the idea of Jev (ultra-fast, typed decision models instead of heavy 70B LLMs), meet Laya—the open-source equivalent. Why it matters for production pipelines: 1. Blazing Speed (<100ms): Avoids slow token-by-token generation. Evaluates options in parallel to make routing/classification decisions in milliseconds. 2. 100% Self-Hostable: Run it locally on cheap hardware (even CPUs). Zero API costs and zero data leaving your servers. 3. Native Typed Outputs: Outputs structured probability distributions directly. No messy regex or JSON cleanup needed. Top Use Cases: • Fast Model Router: Route 80% of easy queries to small models and save frontier LLMs for hard tasks. • RAG Filter: Score and prune retrieved chunks in 40ms before generation. • Real-Time Guardrails: Catch prompt injections before they reach your main agent. The future of AI architecture: Local open-source models handle the fast plumbing. Frontier models handle the deep thinking. GitHub Repo 👇 https://github.com/aayushch/laya #OpenSource #AIEngineering #LLMs #MachineLearning #SystemDesign #BuildingInPublic
Guidex.com
Victor Janni introduces Laya, an ultra-fast typed decision model, as the open-source equivalent of Jev.
Théo
@cryptofanatiix
Most people slap the word “AI” on any Buy / Sell button and leave it there. Jev is a model that came out this week to make fast choices. You give it a situation, and it answers with a decision and a probability: buy, sell, or wait. That takes about 200 milliseconds. It is not a model trained by the Qubic network. It is a tool you call, like an API. X is full of people who wired it to a ticker. Some taped it onto Hyperliquid over a weekend. A few have already posted their losses. That shows what it is: a call returned very fast, then the bot keeps going on its own. So the real subject is not “AI can trade.” It is not mixing two things that do not have the same job. Jev gives an opinion and stops there. It does not stay attached to the error. If the trade is wrong the next day, Jev is not the one carrying the score. The account of whoever plugged in the bot is. BPP-9000 is not built that way. Qubic miners train a small network on a year of Bitcoin hourly candles. The network has to say whether the next hour is more likely to go up, go down, or stay uncertain. Errors are counted. More errors means a worse score. Ant Colony keeps the version that misses less than the last one. That work stays on the network. You can still open a page later and reread the result. The difference fits in two sentences. Jev is a judgment you ask for the length of one call. BPP-9000 is a model the network has to carry for a full epoch. I am not running my bag through a bot someone stood up on a weekend. I am waiting for a public score I can refresh. The question I keep: the day both put up an arrow, which one can you still reread the next morning?
Guidex.com
A short explainer: Jev is not an AI-labelled button, it returns a buy, sell or wait with a probability in about 200 ms.
Guidedeepeval.com
DeepEval’s introduction to JevEval: evals built with Jev as the judge.
Guidenews.ycombinator.com
A weekly roundup of trending open-source AI repositories, Laya-mlx at the top.
Guideacademy.dair.ai
DAIR Academy on building a custom harness with Jev and Pi.
Guidemedium.com
A Towards Data Science walkthrough: a browser extension with Jev deciding.
Guidereddit.com
A r/LocalLLaMA post from someone who says they built and open-sourced the architecture a year before launch.
Guideastgl.com
ASTGL compares local Laya with hosted Jev on typed decisions.
Guideblocks.ai
Blocks.ai rebuilt Jev’s API on top of an open model and used it to play Doom.
Guidenews.ycombinator.com
A Show HN for Blink, a high-performance Jev-like decision model written for C and WebAssembly.
Guideyoutube.com/@KevBuildsApps
Kev Builds Apps wires Jev into an Obsidian vault over MCP: store the media and its metadata in the graph, then ask Jev to retrieve the logo, video or file a task needs instead of guessing.
delost
@thedelost
this is pure f*cking treasure 10 GitHub projects that put Jev between your agent and every decision your agent should stop paying a frontier model to answer yes or no ROUTE THE WORK 01 jev-router > https://github.com/gargpratyush/jev-router 02 jcm-router > https://github.com/adarshmishra07/jcm-router 03 jev-agent-skill-router > https://github.com/GodsBoy/jev-agent-skill-router GUARD EVERY ACTION 04 pi-heed > https://github.com/Nyarlathoteppppp/pi-heed 05 fx > https://github.com/vercel-labs/fx 06 Foreman > https://github.com/thruwire/foreman SCORE WHAT MATTERS 07 LlamaIndex Jev > https://github.com/WiktorB2004/llama-index-jev 08 citation-verifier > https://github.com/MarissaFamularo/citation-verifier PUT IT TO WORK 09 yoshi > https://github.com/compozy/yoshi 10 mastra-jev-moderation > https://github.com/CodeAlive-AI/mastra-jev-moderation the loop: your agent hits a fork > Jev answers with a probability > your code decides what that number allows > the agent moves on 3 builds I'd explore: coding agent: jev-router > fx > Foreman > yoshi support desk: jev-agent-skill-router > mastra-jev-moderation > LlamaIndex Jev research: jcm-router > pi-heed > citation-verifier save this, then build a decision layer for your agents ⭣
Guidex.com
delost's list of ten repos, grouped as route the work, guard every action, score what matters and put it to work, with three suggested stacks for coding, support and research agents.

MIKE
@mikenevermiss
Jev is brand new and there's no tutorial for it yet. so I wrote the prompt that makes Claude read the docs, pick one real use case, and build the agent. it's a runnable code, added failure handling, and a rule for when Claude takes over. paste it in and try it.
Guidex.com
MIKE's prompt has Claude read the Jev docs, pick one real use case and build a runnable agent, with failure handling and a rule for when Claude takes over.
darkzodchi
@zodchiii
Send this Jev prompt to Opus 5.5 or any AI agent it installs Jev → audits your workflow → finds where you waste tokens, time and money then moves repeatable decisions out of expensive Opus calls → upgrading your AI stack beyond 95% of people Copy this now. Thank me later
Guidex.com
darkzodchi's prompt for Opus 5.5 or any agent: install Jev, audit the workflow for wasted tokens, time and money, then move repeatable decisions out of expensive calls.
NO1ennn
@N01ennn
x.com/i/article/2103…
Guidex.com
N01ennn's long guide: mark the decisions in an agent loop, move them off the frontier model, and measure the result. Its best part is the arithmetic for why routing down and back up can cost more than never routing.
Gipp 🦅
@gippp69
x.com/i/article/2103…
Guidex.com
Gipp prices a four-lane event desk and shows where the bill ends up: in the share of events that go to a writing model. Includes an audit lane for the ignored events and a daily bill script. The bill figures are assumed rates, not invoices.
What to read before you build: TypeSafe’s own quickstart, docs and cookbooks, the LangChain harness guide, the awesome-jev lists other builders keep, and the launch coverage.
164 guides