Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare read-only, closed-world, idempotent, non-destructive behavior. The description adds useful context beyond annotations: documents are public only, the response includes an official source URL and deployed content checksum, and arbitrary URLs/private files are not supported.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.