Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
There are no annotations, so the description carries the behavioral transparency burden. It does convey that this is an informational, read-only tool by describing what it covers: inputs, outputs, assumptions, and tables. It does not explicitly say 'it does not perform calculations' or describe the response format, but for a zero-parameter describe tool the behavior is reasonably transparent.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.