Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare read-only, idempotent, open-world and non-destructive, so safety is covered. The description adds genuinely useful context beyond that: the tool only sees the FDA's 20 most recent announcements (~3 weeks), it discloses this limitation to the user, and results are ordered newest first. Return-field detail is partly redundant with the output schema.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.