Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden and does so richly: rewrite cadence (every 20s), staleness limit (<=120s then 503, not charged), per-call cost ($0.01 USDC via x402), the fields each burst carries, and that outcomes are scored 30 minutes post-signal. An agent knows the freshness, cost and failure semantics before calling.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.