Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the tool as read-only, idempotent, and non-destructive. The description adds meaningful conditional behavior beyond these annotations, explaining exactly what happens when providers are connected (authenticated:true, empty pending[]) and when credentials are missing (connect_url for toolkit and per-install URLs). This is valuable, non-redundant context.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.