Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Although annotations cover the write/safety profile (readOnlyHint=false, destructiveHint=false), the description adds real behavioral context: it names the exact state being cleared (UserPreferences.has_seen_tour, all checklist_* flags), notes that the checklist widget is re-shown, and documents the no-op outcome. This is more than the annotations convey and there is no contradiction with them.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.