Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden, and it does disclose meaningful behavior: it triggers a real automated login, scans the entire course list, and mutates the session's permission context. What it omits is significant for a login-performing tool — required prerequisites (extension installed, Chrome running, credentials present), idempotency when called repeatedly, whether re-running re-authenticates, and failure/retry behavior.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.