What problem does it solve? Arrangements often sound flat because every non-lead part is just accompaniment glued to the main melody. This Skill teaches how to write a genuinely independent second line using counterpoint principles, so simultaneous parts act as distinct musical characters rather than filler. ## Core Features & Use Cases - Four Complementarity Axes: Ensures two lines stay independent via rhythmic density, interval colour, contrary/oblique/similar motion, and staggered melodic peaks. - Voice-Leading Checks: Detects parallel fifths and octaves, hidden fifths, voice crossing and overlap, and enforces melodic constraints (no augmented/diminished intervals, no seventh/ninth leaps, stepwise resolution after leaps). - Invertible Counterpoint: Varies a repeated section by swapping upper and lower voices (octave, tenth, twelfth double counterpoint) without adding new material. - Use Case: When a second chorus needs variation, apply an octave double-counterpoint inversion of the existing counter-melody instead of layering new instruments, keeping the material identical but the sound fresh. ## Quick Start Ask the agent to write a counter-melody for your chorus and check the voice leading of the resulting two-part passage against the four complementarity axes.
