If X composes something, X is an artist. The person playing a composed work is a performer. Some people have both the roles of artist and performer for a given work.
To say an AI composes something is anthropomorphizing a computer. If you enter a prompt to make a machine generate work based on existing artists' art, you're not composing (in the artistic sense) and neither is the computer. Math isn't art even if it's pretty or if mathematical concepts are used in art.
The term "director" instead of composer or artist conveys what's happening a lot better with telling machines to generate art via prompts.