The field guide to Jev's open-source ecosystem

What it does This is an awesome-list, not a tool: a hand-curated index of everything orbiting Jev and System One — the typed decision models from TypeSafe that take state in and return calibrated probabilities per option. It covers 25 papers, 46 open-source projects, 35 benchmarks, and a growing pile of independent evaluations, organized into sections from “Built with Jev” to “The Shape Before Jev” (the intellectual lineage) and “What Jev Is Sold Against” (the competition).

The interesting bit Two sections you won’t find in a typical awesome-list: a lineage section tracing the ideas that predate Jev, and a “sold against” section cataloging the alternatives it competes with. That’s a curated map of a whole argument, not just a link dump. The independent evaluations matter too — the list links third-party numbers (JevBench results, local latency reports) rather than only vendor claims.

Key highlights

• 167 entries across 9 sections, including 125 with code and 46 open-weight models
• Tracks open rebuilds of the System One shape: OneJev (0.8B–27B multimodal), browser runtimes, MLX ports, and from-scratch clones
• Includes documented failure modes for Jev 1.13 straight from TypeSafe’s own docs
• Multilingual coverage: Thai, Japanese, and English open decision models with reported accuracy numbers
• CC BY 4.0 licensed, with a companion website and a papers-only spinoff list

Caveats

• It’s a list, not software — the JavaScript repo exists to render the gallery site
• Most benchmark numbers are author-reported, not independently verified by the list maintainers

Verdict If you’re evaluating typed decision models or want to run Jev-shaped inference locally, this is the best starting map. If you wanted a library to install, it’s a reading list wearing a repo’s clothes.