Rehearsal Friction Finder
Paste rehearsal notes and song sections; Jev checks independent friction signals, which code combines into a prioritized practice queue.
Noul Check· yes/no probability
Section · Jev
full primer →The kernel.
Jev answers a short checklist of yes/no questions about Music rehearsal for musicians, each as a probability, and simple rules turn them into pass, review or fail.
Why this primitiveIndependent typed flags turn messy notes into sortable practice priorities without rewriting them.
Kernel
several independent Jev `noul` questions (one per condition) asked together over the same state, combined by explicit code rules
Drives the UI as
a checklist of conditions, each with a 0-1 probability meter and a pass / review / fail colour from code-owned thresholds
Required key.
TYPESAFE_API_KEY
Your TypeSafe key. The mega-prompt asks for it with a secure form and keeps it on the server. Jev returns typed decisions: choice, noul (yes/no probability) and score.
open ↗Add this in your Lovable project under Settings → Secrets before pasting the prompt below.
Appendix · Mega-prompt
The build prompt.
budget · 1 message
Paste into a fresh Lovable project. Make sure the key above is set first. read the build strategy →
Build "Rehearsal Friction Finder" as a ONE-SHOT Lovable build (~5 credits, no follow-ups).
Single-page TanStack Start app, one route, cut scope ruthlessly.
THIS PROMPT IS SELF-CONTAINED
Do not assume the participant knows Jev or has read any other page. TypeSafe Jev is a decision model,
not a text generator. It receives `state` plus a map of typed `questions` and returns JSON that code can
use directly. Use Choice to select exactly one defined option, Noul for a yes/no probability from 0 to 1,
and Score for a probability-weighted position across ordered levels. Keep rules, thresholds, arithmetic,
and actions in code. Use a generative model only if the product separately needs prose.
CONCEPT
Paste rehearsal notes and song sections; Jev checks independent friction signals, which code combines into a prioritized practice queue.
Discipline: Music & Sound Design (Music rehearsal).
Jev pattern: Noul Check (yes/no probability) — several independent Jev `noul` questions (one per condition) asked together over the same state, combined by explicit code rules.
Why typed decisions: Independent typed flags turn messy notes into sortable practice priorities without rewriting them.
ENGINE: TypeSafe Jev (typed decisions, not text)
- Before writing code, ask the participant for `TYPESAFE_API_KEY` with Lovable's secure secret form. Never
ask them to paste it into chat, never prefix it with `VITE_`, and never expose it to browser code.
- Put the callable server function in `src/lib/jev.functions.ts`; do not import a server-only module from UI code.
- Validate the user's input before the handler and read `process.env['TYPESAFE_API_KEY']` inside the handler.
- From the server, call:
POST https://api.typesafe.ai/v1/systemone
Authorization: Bearer <TYPESAFE_API_KEY>, Content-Type: application/json
body: { "model": "jev-latest", "state": <Rehearsal notes, song sections, and upcoming date>, "questions": QUESTIONS }
- Ask all questions in ONE request (they run in parallel and cannot see each other).
- Read Choice from `answers[id].choice`, `.probabilities`, and `.confidence`; Score from `.score`,
`.probabilities`, `.legend`, and `.confidence`; Noul from `.noul` only (it has no separate confidence).
SERVER IMPLEMENTATION (adapt the input name and result mapping to this concept)
```ts
import { createServerFn } from "@tanstack/react-start";
import { z } from "zod";
const Input = z.object({ text: z.string().trim().min(1).max(20000) });
export const decide = createServerFn({ method: "POST" })
.inputValidator((input: unknown) => Input.parse(input))
.handler(async ({ data }) => {
const apiKey = process.env['TYPESAFE_API_KEY'];
if (!apiKey) return { ok: false as const, status: 500, message: "TYPESAFE_API_KEY is not configured." };
const requestBody = {
model: "jev-latest",
state: { text: data.text },
questions: QUESTIONS,
};
let response: Response | undefined;
for (let attempt = 0; attempt < 3; attempt += 1) {
response = await fetch("https://api.typesafe.ai/v1/systemone", {
method: "POST",
headers: { Authorization: `Bearer ${apiKey}`, "Content-Type": "application/json" },
body: JSON.stringify(requestBody),
});
if (response.ok || (response.status !== 429 && response.status < 500)) break;
if (attempt < 2) await new Promise((resolve) => setTimeout(resolve, 750 * 2 ** attempt));
}
if (!response) return { ok: false as const, status: 503, message: "Jev did not respond." };
if (!response.ok) {
const message = (await response.text()).slice(0, 500) || `Jev request failed (${response.status}).`;
return { ok: false as const, status: response.status, message };
}
const result = await response.json();
return { ok: true as const, answers: result.answers };
});
```
In the page component, call `decide` with `useServerFn`, preserve the participant's input while loading or
on error, disable duplicate submissions, and render the returned typed values rather than parsing prose.
QUESTIONS (start here, refine wording if needed)
{
"repeat_issue": {
"type": "noul",
"instructions": "Is the same performance issue reported more than once?",
"criteria": {
"true": "A recurring issue appears across notes or sections.",
"false": "No recurring issue is evident."
}
},
"timing_issue": {
"type": "noul",
"instructions": "Do the notes indicate a timing or synchronization problem?",
"criteria": {
"true": "Timing drift or coordination trouble is described.",
"false": "No timing problem is described."
}
},
"deadline_urgent": {
"type": "noul",
"instructions": "Is the issue relevant to an imminent performance deadline?",
"criteria": {
"true": "The notes connect it to a near-term performance.",
"false": "No imminent performance connection is stated."
}
}
}
DECISION RULES (in code, not in the model)
- choice/score: if confidence < 0.6 show a "needs review" badge instead of acting.
- noul: >= 0.75 = yes, <= 0.25 = no, otherwise "review".
- score: normalise with score / (levels - 1) before combining with weights.
- Missing or malformed answers go to review. Show safe HTTP status and message in the UI. Retry only 429/5xx,
at most twice with increasing delay; never retry 400/401/402/403/404 and never invent results.
- If the product needs prose (a summary, a message), use Lovable AI for that text only; Jev makes the decisions.
UI
a checklist of conditions, each with a 0-1 probability meter and a pass / review / fail colour from code-owned thresholds. Include 2 sample inputs as one-click chips so the demo works instantly.
Tailwind + shadcn, editorial look, footer: "Built during the Creative AI & Quantum Hackathon organised by StreetKode Fam during Indian Krump Festival 14".
NO database, NO auth, NO extra pages, NO tests.
BEFORE YOU FINISH
- Run the app and test both sample inputs through the real server function.
- Confirm the browser receives no API key and no fabricated fallback result.
- Confirm Choice/Score confidence and Noul probability drive the stated review rules.
- Confirm loading, success, review, empty-input, and service-error states are readable on mobile.
Reference only if needed: https://docs.typesafe.ai/api and https://docs.typesafe.ai/primitives
Market sizing.
TAM
$1B music education and rehearsal software
SAM
$120M band rehearsal management
SOM
$2M active ensembles
Indicative figures for hackathon pitches — refine with your own research before raising.
Adjacent entries.
Demo production
Demo Readiness Gate
Paste a demo’s notes and mix metadata; Jev checks independent readiness conditions, which code combines into a go, revise, or hold decision.
Sample clearanceSample License Scout
Paste sample descriptions and project-use details; Jev checks independent clearance conditions, which code combines into a review flag.
Live performance planningSetlist Arc Checker
Paste a setlist with song notes and performance constraints; Jev checks independent flow conditions, which code combines into reorder suggestions or a readiness flag.
Sound designCue Sheet Auditor
Paste a scene cue sheet and production constraints; Jev checks independent cue-integrity conditions, which code combines into a pass or review queue.