Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, providing safety profile. The description adds the crucial UTC timezone context, which affects behavior. However, it doesn't describe output format or edge cases (e.g., handling of invalid dates), so it's not fully complete.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.