Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the behavioral burden, but 'List' and 'all' clearly signal a non-mutating enumeration with no hidden filtering or side effects. It does not describe pagination or access scope, yet for a zero-parameter, read-only listing with an output schema, the core behavior is transparent enough.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.