AI makes the demo. It doesn't make the brief.

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AI can hand you a finished-sounding demo in thirty seconds. It cannot hand a session player what they actually need to record on it.

That gap is the whole problem. A remote session musician gets a rough track and a vague message — “make it feel like the chorus lifts, maybe more energy on the bridge?” — and the first hour of paid studio time goes to reverse-engineering the song instead of playing it. The demo exists. The brief doesn’t.

So over a 24-hour weekend in Lisbon, a small team and I built Session Prep Assistant — and it won 1st place, “Musiversal” challenge — Music Hackspace Hackathon, Lisbon, Spring 2026.

What it does

You drop in a rough idea or an AI-generated backing track. You get back everything a human player needs to nail the part in one take:

  1. Local audio analysis — tempo, key, song structure, and chords, computed on-device. No upload of your audio to a model.
  2. An instrument-specific vibe brief — a producer-style written direction (feel, energy, role, tone), tailored per instrument: drums, guitar, bass, keys.
  3. An engraved chord chart — real notation, with rests for silent bars and a ”?” on low-confidence chords. Honest, not faked.
  4. Play-along stems — separated stems plus a synthesized chord-guide stem to practice against.

The point isn’t to replace the musician. It’s to bridge an amateur or AI idea up to a professional performance, so the expensive part — a real player in a real room — goes to recording, not to explaining the song over chat.

Measured, not vibes

The differentiator I’m proudest of isn’t a feature, it’s a posture.

The pipeline is graded by an automated musician-judge on real songs. Below 85/100, it doesn’t ship. That’s a quality gate, not a prompt you hope behaves. And it’s honest by design: when the analysis isn’t sure about a chord, it says so on the chart instead of inventing precision. We validated the whole thing on a real AI-generated demo with 149 tests before we’d let it on stage.

A tool that confidently lies to a session player is worse than no tool. So this one is built to admit what it doesn’t know.

The team

Built at the Music Hackspace Hackathon (Lisbon, 16–17 May 2026), for the Musiversal challenge:

  • Vitalii Ionov — creator & lead
  • Maria Dmitrievich — engineering, and a musician
  • Angelina Mezhonova — music production and quality

It was a genuinely good room to build in. Music Hackspace ran it; Musiversal — the remote-recording marketplace that connects artists with session players — set the challenge, which is exactly the problem we went after.

Try it

The site is the pitch and the product in one place:

If you do remote session work — or you make demos and keep losing the first take to “wait, what key is this?” — I’d genuinely like to hear what it gets wrong.

Session Prep Assistant — 1st place, Musiversal challenge, Music Hackspace Hackathon Lisbon 2026. Built by Vitalii Ionov & team. Valencia / Lisbon, 2026.