Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint and idempotentHint, indicating safety. The description supplements with formula details (±4% per year, max ±5 years) and a clear disclaimer that results are for reference only and not legal advice, adding behavioral context without contradiction.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.