The lead line to write against, in ascending onset order.
Chord sounding at an absolute beat position, or null when none applies.
OptionalchordExact chord-change beats exposed by the caller's timeline. The generator also probes its half-beat grid, but callback discontinuities between grid points are not introspectable and should be listed here.
Key/scale context for scale-tone decisions.
OptionaltsMeter used for strong-beat decisions.
OptionalregisterWhich side of the melody the counter line occupies.
OptionalrhythmOnset strategy: 'complement' moves where the melody holds or rests and
reinforces some strong beats; 'follow' mirrors melody onsets.
OptionalprofileSafety profile applied to candidate pitches.
OptionalpitchLowest MIDI pitch the counter line may use (default derived from register).
OptionalpitchHighest MIDI pitch the counter line may use (default derived from register).
OptionalseedPRNG seed; the same seed always yields the same line.
Options controlling generateCounterMelody.