Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description is transparent that this is a no-op that does nothing — that's honest behavioral disclosure. No annotations are provided, but the description carries the necessary burden by explicitly stating the tool performs no operation. It does not describe return values or error behavior, but for a no-op tool that's less critical.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.