Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already carry the safety profile (readOnly, idempotent, non-destructive, closed-world), and the description goes well beyond them by disclosing the failure path ('returns destination_ambiguous with a did_you_mean list') and the alias behavior ('Area names resolve to their parent destination and include resolved_via=area_alias'). These are non-obvious runtime traits an agent must plan around.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.