Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, openWorld, idempotent, non-destructive, but the description adds unique behavioral context: k-anonymity via 5-char prefix (full hash never leaves tool), no data stored, and rate limits. This informs privacy and quota implications beyond the structured hints.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.