Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond the annotations it discloses the security model that matters most: the copy runs as the requesting user with their own logins, never the author's, and can call only the functions its listing lists. It also explains the non-obvious idempotent-like behavior (existing copy returned with `alreadyHave: true`), which materially refines the `idempotentHint: false` signal, and names the auth step (`sitesNeedingLogin`, one-time sign-in links) the caller must complete.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.