Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already establish read-only, non-destructive, open-world behavior. The description adds the useful point-in-time notion of a historical cutoff, but it does not explain what "source-record revisions" represent or how the bounded result behaves.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.