Sometimes there is response.error, other times there is an errors array in the root of the response. It's frustrating trying to handle these cases without knowing what to expect with proper documentation.
I still do not see any documentation about the formatting of error responses.
I planned on logging these to a file or dispatching an email, but not having them interrupt operation.
From my own experience and from glancing around the forum, all I see is:
error : type
error : type, description