Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden and does substantial work: it discloses per-call pricing ($0.005), the payment rail (x402, USDC on Base), the input ceiling (4000 chars), the label count bounds, and the single-label output cardinality. It omits error/failure behavior, latency, and whether retries re-charge, which keeps 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.