Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds value by disclosing concrete behavioral details: it returns 'authenticated:true' and empty 'pending[]' when all providers are connected, and returns 'connect_url' when credentials are missing. It does not repeat annotations. Slight credit reduction because it doesn't mention rate limits, caching, or latency behavior, but it goes beyond the annotations meaningfully.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.