NelmioApiDocBundle/Resources/config/swagger_php.xml

<?xml version="1.0" ?>
<container xmlns="http://symfony.com/schema/dic/services"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">

    <services>
        <service id="nelmio_api_doc.describers.swagger_php" class="Nelmio\ApiDocBundle\Describer\SwaggerPhpDescriber" public="false">
            <argument type="service" id="nelmio_api_doc.routes" />
            <argument type="service" id="nelmio_api_doc.controller_reflector" />
            <argument type="service" id="annotation_reader" />

            <tag name="nelmio_api_doc.describer" priority="-200" />
        </service>
    </services>

</container>