Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate non-read-only, non-idempotent, and non-destructive behavior. The description adds value by specifying exactly what is duplicated (analysis, captures, message history, and version-dependent items like live current map and transformation proposal). This provides behavioral nuance beyond the annotations. However, it does not describe error conditions or side effects.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.