There is no error spec :( But [these](https://github.com/jclouds/jclouds/blob/master/core/src/main/java/org/jclouds/util/Throwables2.java#L138-L141) are the top level exceptions jclouds takes into account. Error handlers should try to map responses to these Exceptions, and throw an `HttpResponseException` if no one is appropriate.