Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already convey that the tool is write-oriented, destructive, and idempotent. The description adds no extra behavioral context such as side effects, permissions, or error handling, but it also does not contradict the annotations. The additional value over annotations is minimal.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.