Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries full weight. It states the data source (official MTA GTFS-RT feed) and liveness ('Live'), implying a read-only, non-destructive operation. It does not mention rate limits or authentication, but given the context, the transparency is adequate.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.