Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond the annotations, the description discloses that the server returns a sandboxed iframe, an installation page, and restrictions, and that unknown ids or extra fields produce a JSON-RPC Invalid params error. This meaningfully enriches the read-only, idempotent safety profile already declared by annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.