Pedal marks are completely unreachable through Model A and the agent-facing Model B API

Sustain-pedal notation is a routine, frequently-needed mark for keyboard repertoire — directly relevant to any Gradus keyboard-writing content (chorale realizations at the keyboard, Baroque keyboard fugue).

Gould, Behind Bars, ch. Pedalling — pedal marking is described as ordinary notation for any piano part, not an advanced/rare feature.

This rule can be decided from pitches, durations and voices — no layout required. A validator can check it before anything is drawn.