Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the write/mutation profile (readOnlyHint=false, non-idempotent, non-destructive). The description usefully adds the closed action set and the conditional parameter requirements per action, but says nothing about irreversibility, permission requirements, or what happens to dependent state on cancel/block.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.