Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, and closed-world behavior, so the safety profile needs no restating. The description adds genuinely new behavioral context: that sprints are included, that results are averaged per driver, and that coverage begins in 2023 due to position data availability — a data-availability constraint not expressed anywhere in the schema.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.