Non-required arguments in compojure-api/schema/swagger?

When I have a definition of an API like this:

(POST* "/register" []
    :body-params [username :- String,
                  password :- String,
                  name :- String]
    (ok)))

what's the appropriate way of making name optional? Is it:

(POST* "/register" []
    :body-params [username :- String,
                  password :- String,
                  {name :- String nil}]
    (ok)))

As you know it uses letk plumbing notation and as far as I recall the syntax is correct but the default value should be consistent with the expected type so I'd say it should be "" rather than nil as (string? nil) => false

(POST* "/register" []
    :body-params [username :- String,
                  password :- String,
                  {name :- String ""}]
    (ok)))