Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent and closed-world, so safety is covered. The description adds only that recommendations are personalized per the listed signals; it says nothing about result count, ranking behavior, or whether omitted signals degrade quality — extra context that would be genuinely useful here.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.