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Kev — small decision models built on Qwen3.5, honest about exactly how much accuracy you give up
Kev (Apache-2.0, Python, 1,681 stars, 93 forks, created September 17, 177 commits, 4 contributors, kev-family release September 20) is a family of 0.8B/4B/9B decision models built on Qwen3.5 bases, with an API that matches TypeSafe's System One wire format closely enough that you point their own Python SDK at localhost instead of TypeSafe's servers. uv run python -m kev.serve --run jaredpalmer/kev-4b --port 8009 starts a local server; send it a support ticket with three typed questions (which department, does this need escalation, how frustrated is the customer) and it returns a choice, a yes/no probability, and a 0-2 severity score, each with its own confidence and full probability breakdown, in under 500ms on an Apple M5. Three question types cover most of what an LLM judge or a routing prompt is actually asked to decide.
What sets Kev apart from the rest of today's list is what it says about its own numbers. Kev-9B trails Jev by 3.5 points on out-of-domain accuracy (0.822 vs 0.857) and scores 0.852 on a held-out test set Jev has never been run against — and the README says outright, "we don't know which datasets Jev was trained on, so this isn't a controlled comparison of the two architectures." A KEV_TEMPERATURE calibration setting cuts confident wrong answers from 8.7% to 4.4%, close to Jev's own 3.7%; a KEV_DATE_FACTS flag that hands the model a pre-computed day-count pushes deadline-policy accuracy from 0.80 to 0.90 against Jev's 0.93. Every improvement is quantified against the gap it's closing, not against zero. The HN launch thread (116 points, 55 comments) split the way these threads usually do — one commenter called it "a bit of a Jev explosion," another asked, reasonably, whether tool-calling on an existing chat model already covered most of the use cases this opens up — and the author, Jared Palmer (Turborepo, Formik), didn't oversell past what the tables show.
Reach for it if you want a local, self-hosted decision model without waiting on TypeSafe's access queue, and you can live with single-digit accuracy points below the hosted original on data unlike what Kev trained on; it replaces the hand-rolled few-shot classification prompt you're currently running against a chat model for ticket routing, escalation flags, or rubric scoring. Delete the GPT-4o-mini call you use today just to pick one of five labels. Tradeoffs: 4B and 9B need a 32GB Mac or a CUDA GPU to run comfortably; the context window tops out around 32k per a thread commenter's testing; and every accuracy number in the README is Kev's own eval run, not a third party's.