Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds useful behavior (it expands matchdays by following the site's round links and behaves differently with/without a slug), but says nothing about result volume, pagination, or freshness beyond 'live'.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.