Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already carry the key behavioral safety profile: readOnlyHint=true and idempotentHint=true, so an agent knows this has no lasting side effects. The description adds the 'with question details' scoping fact, which is useful. It does not comment on permissions, errors, or response shape beyond that, so the description adds only a modest amount beyond the annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.