Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the behavioral burden, and it does disclose meaningful non-obvious traits: per-call cost ($0.01/call), a free first query per operator, and the x402 payment flow via the X-PAYMENT header upon a 402 response. It omits failure modes, retry behavior, and whether verdicts are cached, so it is not fully transparent.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.