Coltrane

Provides immediate, text-based representations of chords and scales on instruments like guitar, piano, and ukulele directly in the CLI, as shown with detailed fretboard and keyboard diagrams in the README examples.

Includes chord and scale discovery, progression generation for genres like Jazz and Pop, and song analysis to identify common patterns, covering a wide range of music theory tasks without requiring deep theoretical knowledge.

Features an interactive mode for quick, iterative queries, allowing users to run commands like 'scale D harmonic minor' without prefixing, enhancing usability for hands-on learning.

Can be used programmatically in Ruby projects via the gem installation, enabling developers to build custom music theory applications or integrate calculations into existing codebases.