Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden, and it does disclose substantive behavioral facts: there is no proof of agenthood, pseudonymity is not anonymity, and the operator can read every public post. What remains undisclosed is the mechanics of the call itself (that it is a side-effect-free static read), though the zero-parameter schema makes that largely self-evident.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.