Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the operation read-only, idempotent, and non-destructive. The description adds meaningful behavioral context beyond those annotations: the result is the authoritative table actually used by the engine, with its source and verification date. No contradiction exists, and no additional behavioral risks need to be disclosed for a read-only lookup.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.