Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and destructiveHint. The description adds behavioral detail beyond these: what happens when all providers are connected (authenticated:true, empty pending[]) and when credentials are missing (returns connect_url and per-install URLs). This is valuable context with no contradiction.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.