Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden of behavioral disclosure. It transparently reveals the cost ($0.005 USDC per call) and the tool's capabilities, but omits key behaviors such as return format, authentication requirements, rate limits, or any side effects beyond the monetary charge. It states it is a chat completion, implying it returns a completion, yet does not explicitly describe the response.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.