List every scale type in the database with intervals, degree labels and aliases.

Use a scale type's name (or any alias) with get_scale, match_scales, diatonic_chords and degrees_to_chords.

List every chord type in the database with intervals, degree labels, symbol suffixes and aliases.

Use a chord type's name or symbol suffix with get_chord, and root+suffix symbols (e.g. 'Am', 'G7', 'F#m7b5') anywhere a chord symbol is accepted.

Describe a scale type; with a root note, generate its notes.

Without root: intervals and degree labels only (e.g. major = 0 2 4 5 7 9 11). With root: the spelled notes, e.g. get_scale('major', 'C') -> C D E F G A B C. Give the root an octave for concrete pitches: get_scale('major', 'C5') -> C5 ... C6 plus MIDI numbers. The returned notes array feeds directly into match_chords, random_notes, notes_to_midi, etc.

Describe a chord type; with a root note, generate its notes.

Without root: intervals and degrees only (e.g. minor 7 = 0 3 7 10). With root: the spelled chord, e.g. get_chord('min', 'F') -> F Ab C. Give the root an octave for concrete pitches: get_chord('9', 'C4') -> C4 E4 G4 Bb4 D5 plus MIDI numbers. The returned notes array feeds directly into random_notes, notes_to_midi, match_scales, etc.

Find scales that contain all of the given notes (octaves are ignored).

notes is a list like ['C', 'E', 'G'] or a string 'c e g' — any other tool's notes output works as-is. A match is 'exact' when the input uses every note of the scale; otherwise 'contains', with the scale's extra notes listed in added_notes. Exact and tighter (smaller) scales sort first.

Find chords that match the given notes (octaves are ignored).

'exact' matches use exactly the input pitch classes; when the first input note is not the chord root the inversion is reported with slash notation (e.g. 'E G C' -> C/E, first inversion). 'partial' matches are chords that contain all input notes plus the listed missing_notes.

List the chord built on each degree of a scale (triads, or sevenths).

E.g. diatonic_chords('C', 'major') -> I=C, ii=Dm, iii=Em, IV=F, V=G, vi=Am, vii°=Bdim. Seven-note scales also get roman numerals, degree names and harmonic functions (tonic/subdominant/dominant) — the raw material for designing a progression yourself; then resolve it with degrees_to_chords. A root with an octave (e.g. 'C4') yields concrete pitches with MIDI numbers.

Resolve a chord-degree sequence you chose into concrete chords of a scale.

degrees is your sequence as numbers or roman numerals: [1, 5, 6, 4], 'I V vi IV' or '1-5-6-4'. Returns the chord (symbol + notes) on each chosen degree, in order — e.g. in C major: C, G, Am, F. The symbols array feeds directly into chords_to_midi / song_to_midi. This tool only maps degrees to chords; choosing and ordering the degrees is up to you.

Pick count uniformly random notes from a pool of notes (a pure dice roll).

The pool is any notes array — typically from get_scale or get_chord, e.g. random notes from A minor pentatonic. Octaves in the pool are kept. Reproducible via seed; the seed used is always returned.

Roll a random rhythm pattern of length steps (a pure dice roll).

Returns a pattern string like 'O...Oo..' where O = strong beat, o = weak beat, . = pause. density is the chance a step holds a note; accent_probability the chance a note is strong. The pattern feeds the rhythm argument of notes_to_midi / song_to_midi; you can also edit it by hand first. Reproducible via seed; the seed used is always returned.

Write a note sequence (scale, arpeggio or melody) to a MIDI file.

Plays the notes in order, one per step_beats. With rhythm (a pattern like 'O.oo.O..' from random_rhythm or hand-written), each step follows the pattern: O = accented note, o = soft note, . = pause (notes are consumed in order and wrap around if the pattern needs more; with sustain=true pauses extend the previous note instead). Octave-less notes are placed by octave_policy: 'nearest' for melodies, 'ascending' for scale runs. Returns the file path and base64 plus the exact note events written.

Write a chord sequence to a MIDI file (block chords, or arpeggiated).

chords items are chord symbols ('C', 'Am7', 'F#dim', 'C/E', 'C4maj7' — e.g. the symbols output of degrees_to_chords) and/or explicit note arrays (['C','E','G'] or ['C4','E4','G4']). Octave-less chords are voiced upward from octave. Each chord lasts beats_per_chord. Returns the file path and base64 plus each chord's voiced notes and MIDI numbers.

Write a melody plus chord accompaniment into one two-track MIDI file.

Track 1 plays melody_notes (optionally shaped by melody_rhythm, same rules as notes_to_midi); track 2 plays chords (same formats as chords_to_midi), one every beats_per_chord. You decide which melody notes go over which chords — align them by length: a melody over 4 chords of 4 beats with 0.5-beat steps needs a 32-step rhythm/notes. General MIDI *_program numbers pick instruments (0 piano, 32 bass, 48 strings...).