Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden, and 'Get' usefully signals a read-only retrieval rather than a mutation. Still, it does not disclose error behavior, permissions, or what 'full' means in terms of response contents, leaving some behavioral ambiguity.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.