Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations only say non-read-only, non-destructive, non-idempotent, closed-world; the description adds real value by enumerating the negative side effects: it never publishes, contacts providers, forms a contract, or moves money, and it names the control requirement for the later publish step. The remaining gap is that it does not address duplicate-draft behavior or validation failures, which matters for a non-idempotent create.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.