Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden and discloses almost nothing: not whether this is a read-only fetch, what happens when no voice is configured (empty result vs error), nor what shape the returned style guide takes. 'Get' implies read-only but that is inference, not disclosure.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.