Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description discloses key behavioral traits beyond annotations: it validates inputs, sends an email, returns a pending_id, and imposes a 10-minute requirement. Even though annotations are all false (not read-only, not idempotent), the description aligns and adds meaningful context. It doesn't fully describe what happens on duplicate signups or whether the email is always sent, but the provided details are valuable.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.