Lyric capitalization follows sentence-level rules, not per-note capitalization; punctuation attaches to the syllable it belongs to

Only the first word of a line/phrase and proper nouns are capitalized; punctuation is placed immediately after the syllable that ends the clause, without a preceding space, and does not itself receive a hyphen.

Author capitalizes every syllable of a hyphenated word, or places a comma with a leading space, or attaches a hyphen after a syllable that already ends in punctuation.

Gould general text-underlay practice; standard English orthography carried into engraving practice per Read.

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