Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond the read-only annotation, the description discloses key nuances: questions_for_user is advisory while requires_user_input is server-enforced, and it explains user_provided_fields gating submit_response. This adds significant operational context not available from annotations alone.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.