What it is
A TypeScript playground testing whether TypeSafe's System One model Jev can steer music composition across eight styles, plus an absurd trolley-problem demo, for developers exploring typed model decisions.
How it uses Jev
Jev decides only enum labels: character, form, key, meter, texture, palette, tempo, dynamics, instrument, and per-slot harmony phrases and contours. Code expands these into chords, roles, notes, sheet music, audio and MIDI. An offline HeuristicPlanner stub sits behind the same interface.
Primitives:choicescorenoul
Technique worth stealing
Separating a pure deterministic renderPlan from the planner: nothing upstream knows about notes, nothing downstream knows about Jev.
Try it
npm install && npm run dev — works offline with the heuristic stub; add TYPESAFE_API_KEY for live Jev.
Evidence
Each line is one question put to Jev about the README. ≥ 0.60 reads as yes, ≤ 0.40 as no; in between Jev is not making a call.
- Jev-centricyes0.91
- Shows a System One patternyes0.85
- Handles uncertaintyno0.09
- Measuredno0.05
- Runnableno0.32
- Worth recommendingunclear0.51
- Model replicano0.07
- Problem scopescore on a 0–2 scale0.01
- About Jevyes0.98
Signals by Jev jev-1.13.0, card written by DeepSeek V4.1 Flash from the README on 20 Sept 2026.