Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond annotations that already mark this as a safe read, the description discloses a critical lifecycle behavior: timelines are retained for 24 hours after last use and must be saved externally for longer work. It also clarifies that frame end is exclusive, adding useful semantic detail.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.