Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description still adds real value by scoping the data returned ('Metadata/approved fields only; no secrets, contacts or original files'), which tells the agent what it will and will not get back.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.