Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered without help from the description. The description adds real value by describing the shape of the returned product data (a useful substitute for the missing output schema), but says nothing about behavior for an invalid or stale slug.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.