gistfile1.txt

function custom_json_api_prepare_post( $post_response, $post, $context ) {

    $post_response['do_api_action']['default']['above_title'] = 'this is above the title';
    $post_response['do_api_action']['default']['below_title'] = 'this is below the title';
    $post_response['do_api_action']['default']['above_content'] = 'this is above the content';
    $post_response['do_api_action']['default']['below_content'] = 'this is below the content';

    return $post_response;
}
add_filter( 'json_prepare_post', 'custom_json_api_prepare_post', 10, 3 );