{
  "id": 8407003,
  "title": "Choice, Score and Noul: four mistakes with Jev's primitives",
  "url": "https://urgent.news/2026/09/19/choice-score-and-noul-four-mistakes-with-jevs-primitives",
  "topic": "ai",
  "section": "AI",
  "published": "2026-09-19T06:25:37.000Z",
  "source": {
    "name": "Dev.to",
    "slug": "dev-to",
    "url": "https://dev.to/dave8172/choice-score-and-noul-four-mistakes-with-jevs-primitives-1eng"
  },
  "original_language": "en",
  "account": "I constructed a Magic 8 Ball using System One model Jev from TypeSafe. Jev reads natural language and returns a probability distribution over the options you provide, with no prose, reasoning trace, or JSON repair. I made four mistakes in building my Magic 8 Ball, each costing me about $0.000014. The first mistake was interpreting the Score as a winner. The Score returns a position on your levels, but it's actually a probability-weighted average. The second mistake was assuming low confidence indicated doubt about the answer. Every Choice and Score comes with a confidence rating from 0 to 1, but confidence measures how peaked the distribution is, not the truth of the answer. The third mistake was offering options that split their own vote. An 8 Ball typically has twenty answers, and my ball only had five. When I asked my ball a question, it offered multiple answers that were near-synonyms, causing a disagreement in the options presented. Finally, I forgot that the options are part of the prompt. The model cannot choose an omitted value; leaving an option out makes it impossible for the model to provide that answer.",
  "summary": "Jev is a System One model from TypeSafe. It reads natural language like any LLM, and instead of writing a reply it returns a probability distribution over options you supply. No prose, no reasoning trace, no JSON to repair — a number per option, summing to 1. I spent a week building a Magic 8 Ball on it, which sounds like a toy and turned out to be a decent test rig: every answer is a judgment…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}