Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and openWorldHint=true, so safety and open-world nature are covered. The description adds only that it is 1:1 with the official client and that "parameter and date restrictions follow the official API" — a pointer to external, unspecified constraints rather than a disclosure of them. No info about data source, auth, or limits.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.