Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden, and it does disclose the returned fields (size, timestamp, metadata), which is real behavioral content. But it says nothing about whether the path must exist, error behavior for missing paths or directories, or how 'metadata' relates to note frontmatter — notable gaps for an unannotated tool.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.