Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, and the description adds useful behavioral context: results are newest-first and are summaries rather than full requests. It also points to get_webhook_request for full detail, giving the agent a sense of the data shape without repeating annotation info.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.