| Music Composition Core | Portable music-composition primitives built on Foundation |
| Core | Root module for the reconstructed music domain |
| Pitch | Written pitch primitives: letters, accidentals, note names and pitches |
| Interval | Directed intervals and spelling-preserving transposition |
| Tuning | Frequencies of written pitches under an explicit tuning |
| Scale | Scale patterns, spelled scales and the reviewed scale catalog |
| Chord | Chord patterns, spelled chords, inversions and the reviewed chord catalog |
| Key | Key signatures, keys in the seven diatonic modes and spelling in a key |
| Notation | Text formatting and parsing into caller-provided buffers |
| Rhythm | Exact written durations, independent of playback time |
| Build Guide | Configure MCC against a matching Foundation package |
| Foundation Dependency | Foundation package resolution and compatibility contract |
| Platform Presets | Public MCC presets backed by pinned RoModularBuild profiles |
| Examples | Runnable demonstrations of MCC APIs |
| Music-Domain Specification | Invariants shared by every MCC music-theory module |
| Workflows | Repeatable configure, build, test, documentation, install, and export |
| Shared Build Infrastructure | MCC's pinned RoModularBuild integration and ownership boundary |
| Installed Package Consumer Test | Validate MCC exactly as an independent downstream project uses it |
| Legacy Migration Backlog | Controlled reconstruction plan for the historical MCC codebases |