Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden, and it does add real context: metrics come from synthetic probing of endpoints and history only grows from prober start, which warns the agent about limited historical depth. It says nothing about permissions, rate limits, or error behavior, so coverage is partial rather than complete.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.