Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare non-read-only, open-world, non-idempotent, non-destructive behavior. The description adds important context beyond annotations: the API key is not issued immediately and requires email verification, which is central to understanding the tool's side effects and follow-up flow.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.