Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover read-only, idempotent, open-world, and non-destructive traits, and the description still adds substantial behavioral context beyond them: return ordering (newest first), per-row fields (last_confirmed, stale), the 1/7/30/90-day freshness buckets, and pricing/metering ($0 free, alternatives at $0.05/$0.10). Nothing is left for the agent to infer about cost or shape.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.