Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already carry readOnlyHint=true, and the description adds output composition details (titles, descriptions, thumbnails, publish dates). It does not describe pagination behavior or edge cases, but with read-only safety already declared this is adequate.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.