Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations cover the safety profile (readOnly, idempotent, non-destructive, open world), and the description adds substantial context beyond them: latency (1-3 s), price (USD 0.01 / 0.004 per section), a free tier of 5 per IP per UTC day, the heuristic caveat, and an explicit untrusted-input warning for returned page text and on-chain strings. That is rich operational disclosure.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.