Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden; it does so by explicitly framing the operation as a read ('Read this') and enumerating the exact information returned: source, date computed, licence, and citation. It does not detail output formatting, but that is minor for a parameterless metadata tool.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.