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Jev Mice
A browser colony of mice, cats, traps, and food. Each animal's next move is judged by Jev, or by fixed rules when the model is turned off.
- Format
- Playground
- Reading time
- 3 min
- Published by
- Community
- Last verified
- Sep 2026
Highlights
- The world is mice, cats, traps, and food. You can follow one animal by clicking it.
- Each animal's next move is either a Jev judgment or a fixed rule, depending on the settings.
- The layout puts settings on the left, playback on the right, and a History tab for past moves.
- Show HN posted it on 23 September 2026 as a colony simulation with a deterministic engine beside Jev.
Watch out
The page is a client-rendered app, so this entry follows the public description rather than a server-rendered ruleset. One point on Hacker News. Not a TypeSafe product.
Questions about this entry
Short answers drawn from the linked project or page.
The entry's copy says each animal's next move is either a Jev judgment or a fixed rule, depending on settings. Beyond that the page documents nothing useful: it is a client-rendered app, the extracted text is empty, and no prompt, question type or criteria list is published. You cannot reproduce the behaviour from what is written.
Unknown from the page. It does not publish latency, token usage, cost, or whether the simulation needs your own Jev key at all. The only documented controls are the settings pane that switches between Jev and fixed rules, playback on the right, and a History tab of past moves.
Structurally yes, since the settings let you choose a Jev judgment or a fixed rule per animal, and the History tab keeps past moves. But no agreement, win-rate or divergence metric is reported, so a side-by-side run gives you anecdote-level evidence unless you build your own scoring.
Only clickable, as far as the page documents. There is no repository, license, local build path or self-hosting note anywhere in what is available. It was posted as a Show HN colony simulation with a deterministic engine beside Jev, and the entry follows that public description rather than a server-rendered ruleset.
Yes. Clicking an animal follows it, the settings pane on the left switches each animal between a Jev judgment and a fixed rule, playback controls sit on the right, and a History tab keeps past moves. That is the whole documented interface; nothing further about the world, its rules or the prompt is published.
The page does not say. No prompt, state description or visibility rule is published, so it is impossible to tell whether an animal is scored on its local surroundings or on the whole colony, and whether the mice and the cats are reacting to each other or judged independently each turn.
The Show HN posting calls the non-model path a deterministic engine, which implies repeatable runs, but nothing on the page documents a seed, a turn counter or a way to replay a run, so the determinism is a description rather than something the app demonstrates.
Reactions & coverage
Posts, threads, and videos about this entry from around the web.
Hacker News: Show HN: a mouse colony where each next move is Jev or a fixed rule.
1 pointShow HN: Jev-mice – mouse colony simulation using Jev and deterministic engineRead 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 public Minecraft PvP where a diffusion LM picks moves from structured state.
2 pointsShow HN: Minecraft PvP against DiffusionGemma-as-Jev, 24 ms per decisionRead the thread on Hacker NewsHacker News: Show HN: Jev finished a Pokémon Red run, with the Hall of Fame stats on the landing page.
pancomplex272 pointsShow HN: Jev Plays Pokémon RedRead the thread on Hacker NewsMore Jev resources like this
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