Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds non-obvious behavioral context: support percentages are calculated by Velarion from disclosed vote counts and marked as such in the citation. This is valuable beyond the structured annotations, with no contradiction.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.