Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds nothing beyond that: no indication of what the returned limits contain, whether limits are per-deck defaults or user overrides, or whether they are static or change with study progress.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.