Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already establish readOnlyHint, idempotentHint, and non-destructive behavior, so the description doesn't need to restate those. It adds useful behavioral context by naming the searched content (papers, reviews, decisions) and the return shape (ids, titles, venues). It stops short of describing result ordering or pagination details, but the schema covers limit/offset.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.