NelmioApiDocBundle/Resources/config/services.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">

    <parameters>
        <parameter key="nelmio_api_doc.extractor.api_doc_extractor.class">Nelmio\ApiDocBundle\Extractor\ApiDocExtractor</parameter>
        <parameter key="nelmio_api_doc.form.extension.description_field_type_extension.class">Nelmio\ApiDocBundle\Form\Extension\DescriptionFieldTypeExtension</parameter>
    </parameters>

    <services>
        <service id="nelmio_api_doc.extractor.api_doc_extractor" class="%nelmio_api_doc.extractor.api_doc_extractor.class%">
            <argument type="service" id="service_container"/>
            <argument type="service" id="router" />
            <argument type="service" id="annotation_reader" />
        </service>
        <service id="nelmio_api_doc.form.extension.description_field_type_extension" class="%nelmio_api_doc.form.extension.description_field_type_extension.class%">
            <tag name="form.type_extension" alias="field" />
        </service>
    </services>

</container>