Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With only an openWorldHint annotation and no readOnly/destructive hints, the description must disclose behavioral context. It does not mention permission requirements, idempotency, what happens to existing users, or validation behavior. 'Add users to the account' adds negligible insight beyond the tool name.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.