Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the burden of behavioral disclosure. It clearly signals a read-only operation ('조회한다') and scopes the result to currently enrolled courses)Skip... It does not mention authentication, pagination, or ordering, but those are less critical for a simple list tool and the output schema exists.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.