Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full behavioral burden and does disclose the exact returned content and that it should be the first call. For a zero-argument, read-only introspection tool there is little else to disclose (no auth, mutation, or rate-limit concerns), though it never states it is read-only or side-effect free.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.