PyTheory for Claude Code
Make music — and music theory — straight from a conversation. This is the official Claude Code plugin marketplace for PyTheory. Say "write me a bossa nova in G minor", "what chord is x32010?", "give me a DADGAD Cmaj7", or "what key are these notes in?" and Claude answers in pure Python — composing, analyzing, and exporting MIDI/WAV/sheet music with no samples, plugins, or DAW required.
This repository is generated from the pytheory repo (the source of truth) via
make sync-skill. Edit the skill there, not here.
Install
In Claude Code:
/plugin marketplace add kennethreitz/pytheory-skill
/plugin install composing-with-pytheory@pytheory
One plugin, six skills — installing it gives Claude all of them. Each triggers on its own kind of request, so just ask: "make a four-chord pop loop", "lay down a funk beat with ghost-note snares", "what's the fingering for F#m7b5?", "tune my guitar to drop D", "what key are C E G B D in?", "voice-lead Cmaj7 to Fmaj7", or "turn this hum into MIDI and a lead sheet".
You'll also want PyTheory itself available where Claude runs (prefer uv if you have it):
uv pip install pytheory # or: pip install pytheory
What's inside
Six skills, all in one plugin:
| Skill | What it does |
|---|---|
| composing-with-pytheory | Full arrangements — Score, parts, progressions, melodies, drums, layering — plus the house style (subtle detune, 0.2 humanize, sine/triangle love) and rendering to audio/MIDI. |
| playing-guitar-with-pytheory | Fretboard fingerings, chord shapes & tab, chord identification, scale diagrams, alternate tunings + capo, ~20 stringed instruments, Nashville charts, and the real-time tuner. |
| chord-lab-with-pytheory | A single chord's notes, voicings (inversions, drop-2/3, open), tension/dissonance, Forte number, tritone sub, and voice leading. |
| keys-and-harmony-with-pytheory | Keys and progressions — diatonic chords, Roman-numeral analysis, key detection, secondary dominants, borrowed chords, and modulation. |
| scales-modes-and-tunings-with-pytheory | Scales and modes, "what scale fits these notes?", intervals, overtones, the circle of fifths, and 16 tuning systems / temperaments. |
| transcription-and-notation-with-pytheory | Audio → notes/MIDI, chord recognition, MIDI import, and export to MusicXML / LilyPond (incl. guitar lead sheets) / ABC / tab. |
Links
- PyTheory docs — https://pytheory.org
- PyTheory source — https://github.com/kennethreitz/pytheory
- Try it in your browser — https://playground.pytheory.org
Privacy
This plugin collects no data — see PRIVACY.md.
License
MIT © Kenneth Reitz