Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, so no safety concern is hidden. The description adds useful behavioral context beyond the annotations: output is Markdown and the site chrome is removed. It does not describe error behavior for invalid slugs, but the presence of an output schema reduces the need for that.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.