Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations provide comprehensive hints (readOnlyHint: true, destructiveHint: false, idempotentHint: true, openWorldHint: true), so the description's burden is lower. The description doesn't add any behavioral context beyond what annotations already declare (e.g., no details about what 'statements' are, format of return data, or any constraints). However, it doesn't contradict the annotations, so it meets the minimum baseline with annotations present.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.