Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, but the description adds valuable context: 'no auth, no state changes, no charges.' This goes beyond annotations by clarifying the operational and cost implications, which is especially useful for a pricing tool.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.