Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover read-only, idempotent, non-destructive, closed-world behavior, so the bar is lower. The description still adds real value by disclosing the return shape ('verdict status and a plain-language teaser') and an important limitation ('exact thresholds are not public'), which prevents an agent from promising precise numbers.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.