Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover the safety profile (readOnlyHint=true, idempotentHint=true, destructiveHint=false), lowering the bar, and the description still adds substantial context: pricing ($0.02 per call over x402 on Base), auth requirements (prepaid x-credit-token header, 1 free call/day), no-wallet/no-API-key requirement, and the specific heuristic signals (volume/liquidity ratio, buy/sell symmetry, price movement) that drive the score. No contradiction with annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.