Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden and does disclose the core read-only behavior via 'Get information'. It does not mention response contents, authentication requirements, or failure modes, but for a simple no-parameter getter these omissions are less impactful.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.