Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already mark the tool as readOnly, idempotent, and non-destructive. The description adds useful behavioral detail beyond that, such as the specific backend dependencies checked and the lazy-loading behavior of the embedding model on first sentiment search. No contradiction with annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.