Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover safety (readOnly, idempotent, non-destructive, openWorld), so the description's job is context — and it delivers by disclosing the full inventory of metadata fields returned, plus an example payload, which lets an agent judge whether the call is worth making. It doesn't discuss failure behavior for unknown dataset_ids or response size, keeping it short of a 5.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.