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 tells the agent exactly what information will be returned: columns, numeric-ness, row count, and provenance banner. It does not explicitly state read-only behavior or error conditions, but for a no-parameter metadata tool the disclosed outputs are sufficient.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.