Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, so the description's 'read-only' statement is redundant, but it adds useful context about the scope ('one viewable artifact') and output details (chronological order, anchors, status). It doesn't cover auth/rate limits, but the annotation covers the primary safety profile.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.