Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the transparency burden. It discloses that results are filtered by the current user's permission to add content, which is useful. However, it does not mention pagination behavior (e.g., cursor handling) or the exact structure of returned data, which might be relevant for a list tool.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.