Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already mark it read-only and non-destructive, and the description adds useful behavioral context: the search is scoped to lessons and blog posts, and results include id/title/url plus exact id formats ('lesson:<module>/<section>', 'post:<slug>'). This helps an agent interpret and use results correctly.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.