Fetching status code description with jquery

I'm attempting to fetch status code description I send from asp.net mvc app via jquery and ajax, but can't seem to find where it's hidden.

This is backend:

return new HttpStatusCodeResult(403, "someDescription");  

and this is jquery:

$.ajax({
    url: someUrl,
    method: "POST",
    data: "teamMemberId=" + id,
    statusCode: {
        404: function (obj, textStatus, errorThrown) {
            cancel();
        },
        403: function (obj, textStatus, errorThrown) {
            alert(
                //statusCodeDescription
            );
        },
        200: cancel
    }
});  

Thanks!