Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and non-destructive semantics, so the safety profile is covered without description help. The description adds genuine behavioral context by disclosing the return format (Markdown, numbered verses), which is the useful extra here.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.