Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, but the description adds meaningful behavioral context: the exact return states ('authenticated:true', empty pending[], connect_url) and the existence of per-install URLs. This goes beyond the structured data and enhances the agent's understanding.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.