Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false and destructiveHint=false, so the safety profile is fully covered without the description. The description adds value only by disclosing the shape of the payload (broader/narrower/related), which matters because there is no output schema; it says nothing about missing-URI behavior or label-language fallback.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.