Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden of disclosure. It only states the basic action without revealing important details such as whether it creates a deep copy, how it handles nodes, side effects on the original, required permissions, or the response format.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.