Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already establish readOnly, idempotent, non-destructive and closed-world behavior, so the safety profile is covered. The description adds genuinely new context beyond them: the token is the sole credential, and the response deliberately excludes address, phone and payment details — useful disclosure for an agent handling buyer data.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.