Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the burden of indicating behavior. It clarifies the return content (full detail, including targeting JSON), implying a read operation, but does not disclose error handling, auth requirements, or behavior for nonexistent IDs.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.