Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden, and it does disclose one important trait: it works without an active debugger, i.e. a safe read independent of session state. It does not state whether it is read-only, whether results are paginated, or what the listing contains, leaving gaps for a tool with zero annotation coverage.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.