Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already establish readOnly, non-destructive, and closed-world behavior, so the safety profile is covered. The description adds genuine value by disclosing what the payload contains (section identifiers, Markdown body, current revision), which goes beyond the annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.