Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already mark the tool as read-only, open-world, idempotent, and non-destructive. The description adds value by detailing the response contents (fields, geometry type, record count, capabilities), giving agents a clear expectation of what the tool returns. No behavioral traits are hidden, and there is no contradiction with annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.