Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden. It correctly implies a read-only operation, but does not disclose any potential costs, data freshness, or whether the tool requires certain permissions. However, the simple nature of the operation (listing) makes this acceptable.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.