Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate read-only and non-destructive behavior. The description adds useful behavioral detail beyond annotations by specifying exactly what happens when all providers are connected versus when credentials are missing, including the exact fields returned (authenticated, pending[], connect_url).
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.