Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true, so the tool is clearly read-only and safe. The description adds value by listing what metadata is returned (columns, types, etc.) but does not disclose other behaviors like caching, rate limits, or return format beyond the listed fields.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.