Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and a closed-world scope, so safety is covered structurally. The description adds only the 'Copy and checks' framing about what is being returned, which hints at output content but does not say what happens for an unknown slug or how large the payload is.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.