Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the safe-read profile (readOnlyHint, idempotentHint, non-destructive, closed-world), so the description is not obliged to restate safety. It adds real value by disclosing the return payload (critique, sharpening questions, risks, recommended route, promotion target) and by surfacing the revision-token workflow dependency, which no annotation conveys.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.