Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=true and openWorldHint=true, but the description adds the crucial undisclosed detail that it may SEND real email from the user's address depending on preference. It does not say whether queued declines can be cancelled or reversed, which matters for a destructive, non-idempotent tool.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.