Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate read-only, idempotent, non-destructive behavior. The description adds valuable state-dependent context: it explains the meaning of 'authenticated:true', empty 'pending[]', and the presence of 'connect_url' and per-install URLs when credentials are missing. This goes beyond the annotation flags.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.