Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and destructiveHint=false, covering safety. The description adds meaningful behavior: it returns only the earliest and latest version numbers, not the versions themselves, and supports lookup by slug or id. This is enough for an agent to predict the call's outcome.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.