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, and the description is not obligated to repeat it. But it adds nothing behavioral of its own — no mention of what a facet result contains, how filters interact, or the 10,000 result-window constraint — so it contributes no context beyond the annotation baseline.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.