Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden of behavioral disclosure. It only states that it gets OHLC data; it does not describe the return format, whether adjusted=true is default, or what happens if the previous day is not a trading day. The behavior is minimally defined.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.