Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations exist, so the description bears the transparency burden. It describes the core transformation and a negative property (no WHOIS/ownership), but fails to disclose the output shape of 'labels', how the json, url, and zone parameters are handled, or what 'discarded after the check' means in the context of this tool.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.