Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so safety is covered. The description contributes one extra fact beyond that: secrets are excluded from the returned configuration ('non-secret'), which is a genuinely useful boundary. It says nothing about permissions, rate limits, or scope of the returned config.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.