Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description takes on the burden of behavior disclosure. It states the operation is a lookup and lists return fields, implying a read-only, non-destructive action. However, it does not disclose behavior on invalid input, empty results, or error handling, leaving some uncertainty for the agent.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.