Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already convey destructiveHint: true and idempotentHint: true, indicating it is a non-read-only but safe repeated operation. The description adds no additional behavioral context beyond what annotations provide, such as what happens if the collection is not currently a favorite or if the user is not authorized.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.