Adding UUID to the standard library is defensible for a server-focused language, but making it part of the stdlib binds maintainers to long-term compatibility and support, so the debate should focus on API surface and long term maintenance rather than whether third-party packages exist.

If added, keep the scope small: implement RFC 4122 v4 generation using crypto/rand.Read with correct version and variant bit handling, provide Parse and String, MarshalText and UnmarshalText, JSON Marshal and Unmarshal hooks, and database/sql Scanner and Valuer, and skip v1 MAC and time based generation by default because of privacy and cross-platform headaches.