Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already establish readOnly, idempotent, non-destructive behavior; the description adds concrete behavioral detail beyond annotations by specifying exact conditions and returned fields (authenticated:true, empty pending[], connect_url, per-install URLs). This is valuable transparency for an agent.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.