--- title: Introducing System One Models & Jev | daily.dev description: TypeSafe AI, founded by ex-OpenAI researcher Diogo Almeida, launched a new class of model called System One Models, with the first public model named Jev now... canonical: https://daily.dev/posts/n5x94drbm twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Introducing System One Models & Jev | daily.dev og:description: TypeSafe AI, founded by ex-OpenAI researcher Diogo Almeida, launched a new class of model called System One Models, with the first public model named Jev now... og:url: https://daily.dev/posts/n5x94drbm og:image: https://api.daily.dev/og/posts/N5X94dRbM.png og:image:alt: Post cover image og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Introducing System One Models & Jev **[Primary Tech](https://daily.dev/sources/primarytech)** · [@sergio_napoli](https://daily.dev/sergio_napoli) · 33 upvotes · 0 comments ## Summary TypeSafe AI, founded by ex-OpenAI researcher Diogo Almeida, launched a new class of model called System One Models, with the first public model named Jev now in early access. Rather than generating text autoregressively, Jev produces typed, probabilistic structured outputs directly usable by software, claimed to be two orders of magnitude faster and cheaper than LLMs while being guaranteed free of type errors and hallucinations on schema matching. It's trained with a new method called Reinforcement Learning for Calibrated Decisions (RLCD). The company published workflow evaluations claiming up to 193.6x speed and 444.6x cost improvements versus reference models like GPT-6 Astra and Fable 5.1, alongside demos (a Doom-playing bot and a Wikipedia-racing agent) intended to showcase real-time structured decision-making. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [What is Jev? How System One models could change AI agents : fireup.pro](https://daily.dev/posts/what-is-jev-how-system-one-models-could-change-ai-agents-fireup-pro-eqcqub8on) · FireUp · 1 upvotes · 0 comments - [Jev: System One — Best Partner to LLMs](https://daily.dev/posts/jev-system-one-best-partner-to-llms-8kfcdbklg) · Medium · 2 upvotes · 0 comments --- Tags: [#llm](https://daily.dev/tags/llm), [#reinforcement-learning](https://daily.dev/tags/reinforcement-learning) [View this post on daily.dev](https://daily.dev/posts/n5x94drbm) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"DiscussionForumPosting","mainEntityOfPage":"https://daily.dev/posts/n5x94drbm","headline":"Introducing System One Models & Jev","text":"Shared: Introducing System One Models & Jev","url":"https://daily.dev/posts/n5x94drbm","datePublished":"2026-09-18T01:03:16.250Z","dateModified":"2026-09-18T01:03:16.253Z","author":{"@type":"Person","name":"Sergio Napoli","url":"https://daily.dev/sergio_napoli","image":"https://media.daily.dev/image/upload/s--9nw9sep5--/f_auto/v1725282512/avatars/avatar_hkStKFLZ6PhZC05AjFAtE","description":"I’m a Software Engineer with experience developing software solutions end-to-end.","interactionStatistic":{"@type":"InteractionCounter","interactionType":{"@type":"EndorseAction"},"userInteractionCount":770}},"image":"https://media.daily.dev/image/upload/s--CxzD6vbw--/f_auto/v1722860399/public/Placeholder%2005","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":33},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"sharedContent":{"@type":"WebPage","url":"https://api.daily.dev/r/tKP9uRZkg"},"isPartOf":{"@type":"WebPage","url":"https://daily.dev/squads/primarytech","name":"Primary Tech"}} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Primary Tech","item":"https://daily.dev/squads/primarytech"},{"@type":"ListItem","position":3,"name":"Introducing System One Models & Jev"}]} ```