Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare read-only, open-world, idempotent, and non-destructive behavior, so the description does not need to restate safety. It adds useful behavioral context by clarifying that results concern active attacker-registered character-substitution and visual-confusion domains used for impersonation or phishing, though it does not discuss caching or output characteristics.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.