Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the tool read-only, idempotent, and non-destructive. The description adds meaningful conditional behavior about the response shape, including authenticated, pending[], and connect_url fields. It does not explain what 'pending' contains or partial-connection behavior, but annotations lower the bar.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.