Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond annotations (openWorldHint, idempotentHint), the description discloses key behaviors: Cloudflare returns an authorize URL and auto-writes records after authorization; other providers require manual record addition. This adds value without contradicting annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.