Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already provide readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds value by disclosing the two distinct return states (authenticated:true with empty pending[] vs connect_url and per-install URLs), which is behavioral detail beyond what annotations convey. No contradiction with annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.