Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden of explaining behavior, but it only names the action and input. It does not disclose the output format (e.g., list of offending words vs pass/fail status), limits, or any other behavioral details an agent would need to handle the result correctly.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.