Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden of behavioral disclosure. It merely says 'rename or move' without detailing side effects, safety profile, or potential errors (e.g., whether the operation can overwrite existing folders or requires authentication). This is insufficient for a mutation tool.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.