All Jev resources
This is the full index of everything Jev: 2231 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.
- Entries
- 2231
- Categories
- 11
- Official
- 93
- Community
- 2138
- Source sites
- 148
- Deep dives
- 2231
Last updated . Entries are added as they appear and re-checked when they are touched.
Browse Jev by category
11 ways into the ecosystem. Each category page leads with its own shortlist of starting points.
- Repos & SDKs202Client libraries, adapters, and source code you can build on with Jev, from the official Python and TypeScript SDKs to community ports in Go, .NET, and PHP.
- Integrations & Adapters145Framework, platform, gateway, and database integrations that put Jev inside the stack you already run, from LangChain and Pydantic AI to Postgres and Home Assistant.
- Agents & MCP302Agent runtimes, coding-agent gates and routers, MCP servers, and skill or context tooling that hand an agent Jev's typed decisions.
- Tools & CLIs447Standalone Jev CLIs, desktop apps, playgrounds, and utilities you run directly, from shell history and semantic search to dashboards and meters.
- Cookbooks91Official, runnable Jev recipes that show what decision models are good at, each with its own datasets, latencies, and numbers.
- Demos & Experiments363Playable demos, games, simulators, and experiments that put Jev in the loop, from Mario and drones to moderation firehoses and trading bots.
- Practices & Patterns248How to design Jev states, questions, and confidence gates the right way, from the official patterns to the failure modes worth designing around.
- Guides & Articles224Documentation, write-ups, and community hubs for learning Jev, from the canonical docs to independent tutorials and reviews.
- Benchmarks & Evaluations55Benchmarks, calibration studies, independent evaluations, and observability write-ups that measure how Jev actually behaves.
- Models & Reimplementations99Open reimplementations of Jev, retrained heads on small models, and inference-time tricks that reproduce the System One shape with other weights.
- Media & Talks55Videos, talks, podcasts, and news coverage about building with Jev.
Browse Jev by use case or industry
The same directory, sliced by what you are building and who you are building it for.
All 2231 Jev resources
Search the full directory, or filter by category and tag.
Showing 1–48 of 93 resources
typesafe-ai/WorkflowEvalsPythonStart here with Jev
Hand-picked entries the maintainers recommend first, from official primitives to community tools.
Hawxy/TypeSafeAI.NetC#
tryAGI/TypeSafeAIC#Newest Jev resources
The latest additions to the directory, newest first.
Watch: Jev in action
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.
Discussions about Jev
Threads from Reddit and Hacker News about building with Jev.
Hacker News: Show HN: Ad Spend Guard gates budget before the auction, not the creative after.
Show HN: Gating ad budget with a decision modelRead the thread on Hacker NewsReddit: Reranking rebooking options with a decision model, ranked with reasons.
Hacker News: Pick Verify: a single decision at the warehouse pick station catches confusable picks.
Show HN: Verifying robot picks with a decision modelRead the thread on Hacker NewsHacker News: Decision Index 0.2.1 scores open reproductions of Jev on a frozen suite.
jackbravo4 pointsDecision Index 0.2.1 – 70 open reproductions of TypeSafe Jev's Decision ModelRead the thread on Hacker NewsHacker News: Software Bombe and live Enigma demo where Jev ranks cribs and judges plaintext.
ag_212 pointsShow HN: Jev as the Bletchley Park Analyst: A Software Bombe on EnigmaRead the thread on Hacker NewsHacker News: Show HN for the decide CLI: brew install, file context, and multi-question shell scripts.
vsekhar2 pointsShow HN: Decide – Jev decisions in the shell, scripts, and agent skillsRead the thread on Hacker NewsHow entries are chosen
Every entry is hand-picked against the same bar, whether it comes from TypeSafe or the community.
- Public and working — no paywalls, sign-up walls, or dead links.
- Concrete — it has to be about Jev and the System One API, not generic LLM content.
- Useful today — something a developer can learn from or use right now.
- Distinct — if a similar entry exists, the description has to say what makes this one different: a different runtime, a cheaper path, a measured result, or a narrower focus.
- Documented — repos state their license, and docs are in English or carry an English summary.
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.
Common questions
Short answers about Jev and how this directory works.
What is Jev?
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.
What is the difference between Choice, Score, and Noul?
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.
Which Jev SDKs and client libraries are available?
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.
Is the directory free, and is it affiliated with TypeSafe AI?
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.
How often is the directory updated?
Entries are added as new resources appear and re-checked when they are touched. The directory currently holds 2231 entries from 148 source sites, last updated Oct 12, 2026.
What is a verified deep dive?
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. 2231 of the 2231 entries carry one today.
For the canonical details, read the official TypeSafe docs and the API reference.
From the Jev community
Posts from builders shipping with Jev right now.