Ableton Theory Coach

Ableton Theory Coach

Read MIDI from the Set and explain the music theory behind it — detected key/scale, chord names and functions (Roman numerals), the progression, melodic analysis, and voice-leading observations. Educational: it teaches why a part works, not just what it is.

When to use

Triggers: "analyze this clip", "what chords/key is this", "explain the harmony/progression", "voice-leading". To generate music use the composition skills; this one explains existing MIDI.

Process

1. Use ableton-live-runner for build/run/kill + scaffold.
2. Read the target clip's notes (clip.notes) and the project context (song.rootNote,

song.scaleName, song.scaleIntervals).

1. Analyze:

• Pitch-class content → infer key/scale (compare note set to major/minor/modal templates; the

project scale is a strong prior).

• Chords → group notes overlapping in time per beat/bar; identify root + quality (triad, 7th,

9th, sus, slash) from intervals.

• Function → Roman numerals relative to the key; flag cadences, secondary dominants, modal

interchange, the turnaround.

• Melody → contour, chord-tone vs non-chord-tone usage, motif/repetition, range.
• Voice-leading → common tones, smooth vs leapy motion, parallel intervals.

1. Explain clearly — concise, leveled to the user; name the theory and say why it sounds the way

it does (e.g. "the ♭6 over the tonic is what makes it eerie").

1. Optionally render a WebView report with api.ui.showModalDialog(url, w, h, onResult, onError) —

it takes a file URL, not inline HTML: write the HTML to environment.tempDirectory / storageDirectory and pass its file:// URL; the callback returns a string. Or just print the analysis.

Chord-detection sketch

function chordsByBar(notes, bpb = 4) {
  const bars = {};
  for (const n of notes) { const bar = Math.floor(n.startTime / bpb); (bars[bar] ??= []).push(n.pitch % 12); }
  return Object.entries(bars).map(([bar, pcs]) => ({ bar: +bar, pcs: [...new Set(pcs)].sort((a, b) => a - b) }));
}
// match each bar's pitch-class set against interval templates {maj:[0,4,7], min:[0,3,7], m7:[0,3,7,10], ...}
// to name root + quality; then convert to a Roman numeral relative to song.rootNote.

Limits

• Detection is heuristic — ambiguous sets (e.g. rootless/quartal voicings) may need the bass clue or a

best-guess with alternatives stated.

• Reads notes only; expression/automation isn't analyzed.

See ableton-reharmonize, ableton-topline, ableton-describe-to-midi.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: Korben00
• Source: Korben00/ableton-producer-skills
• License: MIT

Install and usage instructions live in the source repository linked above.