Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
readOnlyHint=true already establishes this as a safe read. The description adds useful behavioral detail about the payload ('codes with their meanings', courses 'resolved'), hinting at expansion of codes/relationships, but it does not clarify what 'resolved' means operationally or how missing/unmapped data is handled.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.