Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and destructiveHint=false, so the description adds value by explaining conditional behaviors: it returns 'authenticated:true and empty pending[]' when all providers are connected, and provides 'connect_url for the toolkit and per-install URLs' when credentials are missing. This clarifies response structure beyond what annotations convey.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.