Every note guaranteed. Shipped alone.
Guitar tools mostly show you shapes and hope. The harder problem is generating playable material that is provably correct - not probably in key, but in key by construction.
- The Brief
A learner cannot hear which note is wrong; that is why they are learning. A tool that produces plausible output with occasional wrong notes is precisely worthless to the person who cannot detect them.
- Diagnosis
Make the engine incapable of producing a wrong note. Key membership becomes a constraint enforced by the system, not a probability sampled by it - and the guarantee is enforced by a test suite rather than asserted by copy.
- The Build
01 · Determinism over generation-by-vibes
Pick a scale, a tuning and a technique; every generated note is in key by construction. Thirteen scales including the modes and both minor variants. The store listing states the thesis in six words: not guessed, the engine enforces it.
02 · Engine first, product second
The engine was built as owned research and hardened long before an interface existed. The app wraps it without diluting it. The correctness guarantee is the product, so it had to exist before the pixels.
03 · Shipping is a command, not an afternoon
Release automation is scripted against Apple’s App Store Connect API - the launch itself was pressed through the API. Friction you tolerate becomes cadence you accept, so the friction was removed first.
- Artifacts Delivered
- 01Deterministic music engine - 55 modules, 176 test functions
- 02Native iOS app, live worldwide, free with in-app purchases
- 03Scripted release automation against App Store Connect
- 04Practice Packs feature shipped after launch
- Outcome
Live on the App Store, approved on the first submission in under four days with no rejections, and still shipping features weeks after launch.
- Receipts
- 1,397,760in-key exercises the engine can produce
- under 4 daysto App Store approval, first submission, zero rejections
- 3 daysfrom v1.0 to v1.1.0 - and Practice Packs after that
- Not yet known
- —Downloads to date
- —Conversion to in-app purchase
- —Revenue
App Store Connect holds all three and they are not published here. A product weeks past launch with no promotion behind it has numbers that say more about patience than about the product; they are worth reporting after a first promotion cycle, not before.
"Not guessed. The engine enforces it."