Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the agent knows this is a safe read operation. The description adds substantial context beyond the annotations: it specifies that runs are ordered newest-first, paged, and details the content of each run (changed, diffScore, signed image URLs) plus the response structure { items, nextCursor }. This provides a clear picture of behavior without contradicting the annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.