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 known. The description adds valuable behavioral context by listing exactly what is returned (extraction source, corroboration score, source list, verification date, freshness summary), helping the agent anticipate output structure.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.