config\routes.php

<?php
	Router::parseExtensions('json');
	Router::connect('/', array('controller' => 'pages', 'action' => 'display', 'home'));
	Router::connect('/pages/*', array('controller' => 'pages', 'action' => 'display'));
	CakePlugin::routes();
	require CAKE . 'Config' . DS . 'routes.php';

Controller\TasksController.php

<?php
App::uses('AppController', 'Controller');

class TasksController extends AppController {

	public $components = ['Session', 'Paginator', 'RequestHandler'];

	public function index() {
		$this->Task->recursive = 0;
		$this->Paginator->settings = $this->paginate;
		$this->Paginator->settings['limit'] = 16;
		$this->set('tasks', $this->Paginator->paginate());
		$this->set('_serialize', ['tasks']);
	}
}

curl.text

$ curl -XGET -v cake.localhost/tasks.json
* Adding handle: conn: 0x7ff24b804000
* Adding handle: send: 0
* Adding handle: recv: 0
* Curl_addHandleToPipeline: length: 1
* - Conn 0 (0x7ff24b804000) send_pipe: 1, recv_pipe: 0
* About to connect() to cake.localhost port 80 (#0)
*   Trying 127.0.0.1...
* Connected to cake.localhost (127.0.0.1) port 80 (#0)
> GET /tasks.json HTTP/1.1
> User-Agent: curl/7.30.0
> Host: cake.localhost
> Accept: */*
>
< HTTP/1.1 200 OK
< Date: Wed, 10 Dec 2014 03:07:50 GMT
* Server Apache/2.2.26 (Unix) DAV/2 PHP/5.4.32 mod_ssl/2.2.26 OpenSSL/0.9.8za is not blacklisted
< Server: Apache/2.2.26 (Unix) DAV/2 PHP/5.4.32 mod_ssl/2.2.26 OpenSSL/0.9.8za
< X-Powered-By: PHP/5.4.32
< Content-Length: 15719
< Content-Type: application/json; charset=UTF-8
<
{
    "tasks": [
        {
            "Task": {
                "id": "1",
                "milestone_id": "1",
                "user_id": "1",
                "title": "go go power rangers.",
                "description": "testing",
                "completed": false,
                "created": "2012-07-16 21:21:04",
                "modified": "2014-06-16 02:48:42"
            },
            "Milestone": {
                "id": "1",
                "title": "Kick ass",
                "description": "aww yeah",
                "due_date": "2012-07-15",
                "completed": false,
                "project_id": "1",
                "created": "2012-07-15 19:46:49",
                "modified": "2012-07-15 19:46:49"
            },
            "User": {
                "id": "1",
                "username": "mark",
                "password": "ebdcb0d611eee4e2509632e2644b96d3906d8be6",
                "created": "2012-09-14 09:35:36",
                "modified": "2012-09-14 09:35:36"
            }
        }
    ]
}
* Connection #0 to host cake.localhost left intact