Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover readOnly, idempotent, non-destructive and closed-world, so the safety burden is lifted. The description still adds real value by disclosing the fixed record count (308) and the shape of each record (metric label, route, data URL, verified/pending source status), which tells the agent what it will get back. Pagination and rate-limit behavior remain unstated.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.