I've been using Jev by @typesafeai Here's the six things i've tried and am confident I'll still use Jev for 60 days from now. There's many more experiments, ideas, and things I think I will use it for. It's a big deal (more on why in next post). But I am only sharing things Show more
super-jev
An experimental TypeScript harness that connects evidence to Jev judgments, permitted actions, and verified outcomes, with pluggable data sources and tools, local JSONL traces, and zero runtime dependencies.
- Category
- Repos & SDKs
- Published by
- Community
- Author
- Kevthetech143
- Added
- 2026-09-22
Highlights
- One bounded run tracks state, fetches evidence through observe, batches typed questions, validates answers, permits one tool, and verifies the outcome.
- Runs end as success, stopped, blocked, or error, bounded by maxSteps, timeoutMs, maxRequestBytes, and maxRepeats.
- The byte budget is a local size guard, not a tokenizer, and retries are not automatic; an action_started without action_completed needs reconciliation.
- Journals record context, answers, and outcomes; credentials stay out of trace payloads and raw error text is omitted.
- The suite has 50 tests, and a live jev-1.13.0 response is checked in as a fixture that confirmed the documented score rule and disproved one inferred rule.
Quickstart
import { run, Jev, JsonlJournal } from './src/index.ts';
import { recovery } from './examples/domains.ts';
const result = await run({ domain: recovery(), initial: { restarted: false, healthy: false },
evaluator: new Jev(), journal: new JsonlJournal('runs/my-run.jsonl'),
maxSteps: 10, timeoutMs: 30_000, maxRequestBytes: 100_000, maxRepeats: 2 });
console.log(result.status, result.state);Watch out
MIT-licensed but experimental V0.2.0 and not affiliated with TypeSafe AI; needs Node.js 24+ and TYPESAFE_API_KEY, plugins run in-process as trusted code without sandboxing, and there are no automatic retries.
More like this
From the community
Posts from builders shipping with Jev right now.
Six uses that stuck after 60 days
Security decisions that fit Jev
This made me rethink where AI actually fits into security engineering. For purely engineering work, forget about ChatGPT or Claude. TypeSafe AI just released Jev, and I think it’s going to change how we build AI into security workflows. Instead of asking an LLM to “investigate Show more
we are officially out of stealth! join the frontier and get access to Jev on our website (link on profile)
A million judged questions
Ask Jev anything. Give it a try at askjev.ai It won't answer. It will judge. Let's see if we can get to 1 million questions. @typesafeai 🤝 @convex work great together. @hmartenjoyer @CompleteSkeptic @justKDeng @mikeysee
Inferring Jev's internals from 1,000 calls
Jevの内部アーキテクチャを推測している技術記事(Jev’s Architecture Unmasked)からメモ。 ・本記事はJevのAPIを約1万回の呼び出して、内部構造を推測したもの ・従来の言語モデルを用いた分類やルーティングでは、トークンを1文字ずつ逐次生成するために膨大な無駄な計算コストが発生していた。 Show more
The open System One roundup
Jev 发布没几天,开源社区已经开始疯狂复刻了🔥 最值得推荐的五个模型: 1、Laya 421M:原生决策模型,支持 Mac 2、Decider-2B:最像 Jev,基于 Qwen3.5 3、NanoJev 0.6B:专门的 Decision Head 4、Reflex:Qwen3.5 + Direct Logits 5、System-One 4B:专门做概率校准 Show more
Jev 刚发布没几天,开源社区就出现了同款🔥 Decider-2B模型,是基于 Qwen3.5-2B 做了特殊调整 它和 Jev 模型是一样的 只做选择 评分和判断 不是文本类的 LLM 模型 但两者还是有几个明显区别: 1、模型 Jev:闭源 System One Model Decider:Qwen3.5-2B,约 1.9B 参数,Apache 2.0 开源 2、价格
The launch post
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 Show more

