Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds real behavioral context by naming the exact payload (question records, types, images, time limit, answer choices) and explicitly scoping out correctness, answer checks, and user activity, which prevents the agent from expecting scoring/gameplay data.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.