Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden of behavioral disclosure. It adds value by specifying that the return is 'base64-encoded file content', which is crucial for understanding output format. However, it lacks details on error handling (e.g., if the file doesn't exist), performance aspects like file size limits, or security considerations, leaving gaps in behavioral context.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.