Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, indicating a safe, non-destructive read operation. The description adds value by disclosing plan-specific rule limits (PRO=5, ULTRA=20), which is not in annotations. 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.