Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the behavioral disclosure burden. 'List' strongly implies a non-mutating, read-only operation, and 'persistent Python session' adds useful state context. However, it does not disclose behavior for invalid or expired session IDs, or clarify that only names are returned rather than values, though the output schema likely covers return shape.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.