# pedrozath/coltrane

🎹🎸A music theory library with a command-line interface

Repository: https://github.com/pedrozath/coltrane
Canonical: https://ross.abutalabs.com/products/coltrane
Language: Ruby
License: MIT
License Family: permissive
Topics: music, ruby, gem
Last push: 2025-01-29T18:17:15+00:00

## Health v2 (maintenance only)
Score: 34/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 4, release rhythm 35, longevity 100
- inputs: {"age_days": 3382, "days_push": 581, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2398, forks 69 (observed 2026-08-28T04:06:43.687418+00:00)

## What it is
Coltrane is a Ruby music theory library with a companion command-line interface for calculating chords, scales, and chord progressions. It renders results as guitar, bass, piano, or ukulele fretboard/fingering diagrams directly in the terminal.

## Use cases
- find the name of a chord from a set of notes
- discover scales containing a given chord or note set
- generate chord progressions for jazz, blues, or pop
- see how to play a chord on guitar or ukulele
- find chords common between two scales
- explore music theory from the terminal

## When to choose
- you want a scriptable music theory calculator in Ruby
- you need chord/scale answers without reading sheet music
- you want instrument-specific voicings rendered in the terminal

## When to avoid
- you need audio playback or MIDI production features
- you want a GUI music theory app
- you work outside Ruby and don't want a CLI dependency

## Facets
- artifact type: cli-tool
- maturity: active
- function: cli
- domain: education
- platform: cli, cross-platform
- tags: music-theory, chords, scales, ruby-gem, guitar, piano, command-line

## Member repositories
- pedrozath/coltrane (main) score 34

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:43.687418+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T02:34:19.358484+00:00, confidence not recorded.
  - readme: https://github.com/pedrozath/coltrane (fetched 2026-08-28T04:06:43.687418+00:00, sha 30d168306060)
- Data as of 2026-08-30T08:39:29.467469+00:00.