Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The annotations already establish this as a read-only, idempotent, non-destructive operation. The description adds useful behavioral context by disclosing the not-found fallback: it returns a list of available slugs, which is not visible in the annotations or schema.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.