Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations declare a non-read-only, open-world, non-idempotent operation, and the description usefully adds that the work runs as an asynchronous runner job and that no connection requests are sent. It still omits operational traits such as how long the job takes, how to track its status, or that repeating it creates a new run.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.