The Harmonic Tree is a real-time harmonic exploration and visualization system that provides an interactive "GPS" for chord progressions. Built as part of the MONK ecosystem, it runs on the TMA device and communicates with the TMA desktop application. Each node represents a chord candidate, and branches represent different harmonic paths — diatonic, modal interchange, modulation, parallel, and more.

Click any chord tile to generate its own harmonic sub-map. Build recursive trees showing harmonic paths of arbitrary depth with visual arrows connecting branches. Active path highlighting shows your current exploration branch, and clicking different tiles replaces the branch rather than stacking duplicates.

The engine supports seven transition types: Diatonic (moves within the current scale), Dominant (strong pull to tonic V→I), Modal Interchange (borrowed chords from parallel modes), Modulation (key change), Chromatic Mediant (cinematic major 3rd shifts), Deceptive (V→vi surprise resolution), and Parallel (major↔minor same tonic). Each type has its own color and scoring weight.

Composers can explore where a progression can go next. Educators can visualize harmonic relationships for students. Live performers can preview transitions without committing. Analysts can study relationships between modes and keys. The Harmonic Tree transforms music theory from a static reference into an interactive, living map.