Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the behavioral burden. 'List' implies a read-only operation and 'loaded plugins' clarifies that empty or unloaded slots are not included, but the description does not disclose output format, ordering, or behavior for invalid track numbers.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.