Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already establish read-only, idempotent, non-destructive behavior. The description adds useful non-annotation context: the underlying source (HDX CKAN Action API) and that no auth is required. This meaningfully extends the agent's understanding of call prerequisites without contradicting the annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.