Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the behavioral burden. It discloses the output behavior (output the JSON returned by the interface) and implies a read-only query operation. It does not explain what happens if the task is still running, fails, or the req_id is invalid, leaving some behavioral ambiguity.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.