Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the burden of explaining behavior. It clearly communicates that the tool is a read-style query returning diagnostic stop information, which is useful. It does not disclose edge cases such as what happens if no stop has occurred, whether session_id must refer to a valid session, or the exact response structure, so transparency is only partially complete.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.