jev is insane 🤯 here is jev playing smash bros against itself he is controlling all 4 different characters. and literally deciding whats the best move to play against itself all within a fraction of a second i used over 22 million tokens to play this match and it only cost Show more
Core Concepts
State
The content a request asks Jev to evaluate: a string, a named object, or an array of messages, shared by every question in the request.
- Category
- Core Concepts
- Also known as
- —
- Related terms
- 5
- Directory entries
- 3
- Docs
- docs.typesafe.ai
- Added
- 2026-09-24
Definition
State is the material you would present to a panel of experts before asking for a judgment: a support message, a passage, a conversation, a record, or the current state of your application. It can be a plain string, a JSON object with named fields, or an array of text values.
One request pairs one state with one or more questions. Every question sees the same state and is evaluated independently. Objects are recommended for most requests, and trimming state to what the questions need is part of the craft because unrelated detail causes context rot.
Tagscoreapi
Related terms
Definitions that connect to this one.
QuestionA named judgment for Jev to make about the state, defined by an ID, a type, instructions, and criteria for the typed primitives.Core ConceptsContext rotThe accuracy loss that comes from padding state with detail unrelated to the question; filter state before sending it.Core ConceptsBacktick path referenceNaming a state field inside instructions with backticked dot-and-index paths, such as `ticket.messages[0].text`.PrimitivesText-only inputJev evaluates strings, JSON objects, and arrays of text; images, audio, and video are not supported and must be pre-processed.Core ConceptsDecompositionBreaking a broad judgment into one question per factor, then combining the answers with weights and rules you control in code.Core Concepts
From the directory
How to shape what Jev evaluates: a string, a named object, or an array of messages. Every question in a request sees the same state and is evaluated independently.
Practices & PatternsDocs#official#docs#state
Official
The raw HTTP contract behind every SDK: POST a state plus typed noul, choice, and score questions to /v1/systemone, and get one answer per question, with error codes and retry guidance.
Sites & GuidesDocs#official#docs#api
Official
A maintained list of jev-1.13's known failure modes, literal reading, unreliable counting, dates as text, indirection, context rot, and contradictory criteria, each with a guardrail.
Practices & PatternsDocs#official#docs#evaluation
Official
From the community
Posts from builders shipping with Jev right now.
Jev plays Smash Bros. against itself
A keystroke oracle that reads intent in ~100 ms
Also have been playing with @typesafeai Jev, insane! So many immediate use cases and new apps are possible. What a time to be a builder! Sharing some experiments here starting with: Keystroke oracle / predictive launcher: Your launcher ranks by aliases, fuzzy match, and Show more
A second-hand shopping agent
Claude me integró Jev con Playwright para buscar usados. Lee unos 26 artículos por minuto y decide qué hacer con cada uno en 406 milisegundos Descartó los que no encajaban con lo que busco, ofertó por los que sí y hasta les mandó un mensaje a los vendedores cuando faltaba algún Show more
Predictive spreadsheets
Another crazy @typesafeai Jev example: Predictive spreadsheets Spreadsheets recalculate numbers, not meaning. Jev reads intent. Type "Urgency" at the top of a column and, as you type, it figures out you want each row rated from "no follow-up needed" to "urgent" in ~100 ms.
@dabit3
Also have been playing with @typesafeai Jev, insane! So many immediate use cases and new apps are possible. What a time to be a builder! Sharing some experiments here starting with: Keystroke oracle / predictive launcher: Your launcher ranks by aliases, fuzzy match, and
The compaction plugin, in Chinese
连 JEV 的联合创始人 @CompleteSkeptic 都亲自下场转发点赞：这是 JEV 正确的打开方式！ 大家在 Claude Code 里写长代码，最恶心的就是上下文一满，系统就卡住 10 秒去写总结小作文 开发者 @tamarajtran 刚刚开源了这个插件：利用 JEV 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
WTF is Jev, and 9 things people are building
TL;DR of my new article: WTF is Jev by @typesafeai, and the 9 things people are already building with it. The thesis: 𝗮 𝗰𝗼-𝗰𝗿𝗲𝗮𝘁𝗼𝗿 𝗼𝗳 𝗖𝗵𝗮𝘁𝗚𝗣𝗧 𝘀𝗽𝗲𝗻𝘁 𝘁𝘄𝗼 𝘆𝗲𝗮𝗿𝘀 𝗶𝗻 𝘀𝘁𝗲𝗮𝗹𝘁𝗵 𝗼𝗻 𝗮 𝗺𝗼𝗱𝗲𝗹 𝘁𝗵𝗮𝘁 𝗰𝗮𝗻𝗻𝗼𝘁 𝘄𝗿𝗶𝘁𝗲 𝗮 Show more
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