Agostini was fond of musical enigmas, puzzles, surprise and double-entendre, and his many musical collections display this. "Enigmi musicali" and "L'echo, et enigmi musicali" are canons to be solved by riddles, full of unusual chromatic progressions, instrumental interpolations, and other musical curiosities. Some of his books of madrigals are written in a virtuoso singing style obviously intended for the three current members of the "concerto di donne" (Laura Peverara, Anna Guarini, and Livia d'Arco). His third book of madrigals, for six voices (1582), appears to be the earliest collection of the actual repertory of this ensemble.