Function satisfies 

pub fn satisfies(e: &ModelEntry, reqs: &[Requirement]) -> bool

Can this entry serve a request needing reqs?

No registry write path emits vision today, so a Vision requirement disqualifies every current entry — auto-substitution goes inert for image requests rather than answering them blind. The same code makes a finer distinction the day entries start declaring it; there is no second version of this function to write later.