Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false (mutation), destructiveHint=false (not destructive), and idempotentHint=true. The description adds little beyond that, only implying the favorite is scoped to the authenticated user. It does not describe any additional side effects, permissions, or response behavior, but does not contradict the annotations either.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.