Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the burden and does so well: it discloses the effect (read-only access for the staff member), the scope ('nothing can be changed by staff'), the duration (the requested hours), and the start time ('starting now'). It leaves out error behavior for non-pending requests and any audit/permission requirements beyond the admin role.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.