Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden of behavioral disclosure. 'Get details' implies a read-only operation but does not state what details are returned, whether the resource can be absent, what errors occur, or whether any scoping or permission requirements apply. The description adds minimal behavioral context beyond the obvious meaning of the name.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.