Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the burden. It indicates a read-only listing operation but does not disclose return format, ordering, pagination, or any potential pitfalls (e.g., hidden bases, performance with large vaults). It adds basic context but lacks richer behavioral detail.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.