Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false, openWorldHint=false), so the bar is lower. The description still adds real behavioral context: output length is bounded to 2-4 sentences, answers come only from internal knowledge, and unknown topics trigger an honest fallback rather than fabrication.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.