How to update Guzzle service description for v5?

I have the following service description that I had used for quite a while with older version of Guzzle:

[
    'name'        => 'Gist',
    'apiVersion'  => 'v3',
    'baseUrl'     => 'https://api.github.com/',
    'description' => 'Gists and comments access',
    'operations'  => [
        'GetGists'    => [
            'httpMethod' => 'GET',
            'uri'        => '/users/{user}/gists',
            'parameters' => [
                'user'  => [
                    'location' => 'uri',
                    'required' => true,
                ],
                'since' => [
                    'location' => 'query',
                ],
            ],
        ],
        'GetComments' => [
            'httpMethod' => 'GET',
            'uri'        => '/gists/{id}/comments',
            'parameters' => [
                'id' => [
                    'location' => 'uri',
                    'required' => true,
                ],
            ],
        ],
    ],
]

Now I am moving bunch of thing to a current version of Guzzle and this absolutely refuses to work with newer broken out guzzle/services.

My code is along the lines of:

$client = new Client;
$client->setDefaultOption('verify', false);
$description  = new Description($this->getServiceDescription());
$guzzleClient = new GuzzleClient($client, $description);
$command      = $guzzleClient->getCommand('GetGists', [ 'user' => $this->user ]);
$gists        = $guzzleClient->execute($command); // $gists is empty array?..

It clearly understands command at least partially, since it will complain if I don’t provide required argument or misspell name.

But in the end it’s just empty array and no remote idea what I need to do to troubleshoot it or how do I need to update service description.

The URL it should (does?) access is https://api.github.com/users/Rarst/gists

Answer

Ok, it seems that model is mandatory to interpret response and I got it to working (without much understanding of what and how model controls : ):

[
    'name'        => 'Gist',
    'apiVersion'  => 'v3',
    'baseUrl'     => 'https://api.github.com/',
    'description' => 'Gists and comments access',
    'operations'  => [
        'GetGists'    => [
            'responseModel' => 'getResponse',
            'httpMethod'    => 'GET',
            'uri'           => '/users/{user}/gists',
            'parameters'    => [
                'user'  => [
                    'location' => 'uri',
                    'required' => true,
                ],
                'since' => [
                    'location' => 'query',
                ],
            ],
        ],
        'GetComments' => [
            'responseModel' => 'getResponse',
            'httpMethod'    => 'GET',
            'uri'           => '/gists/{id}/comments',
            'parameters'    => [
                'id' => [
                    'location' => 'uri',
                    'required' => true,
                ],
            ],
        ],
    ],
    'models'      => [
        'getResponse' => [
            'type'                 => 'object',
            'additionalProperties' => [
                'location' => 'json'
            ]
        ]
    ]
]