diff --git a/letsencrypt/client/interfaces.py b/letsencrypt/client/interfaces.py
index 80a43f885..3ce0e990a 100644
--- a/letsencrypt/client/interfaces.py
+++ b/letsencrypt/client/interfaces.py
@@ -5,6 +5,26 @@ import zope.interface
 # pylint: disable=too-few-public-methods
 
 
+class IPluginFactory(zope.interface.Interface):
+
+    def __call__(config):
+        """Create new `IPlugin`.
+
+        :param IConfig config: Configuration.
+
+        """
+
+    def add_parser_arguments(add):
+        """Add plugin arguments to the CLI argument parser.
+
+        :param callable add: Function that proxies calls to
+            `argparse.ArgumentParser.add_argument` prepending options
+            with unique plugin name prefix.
+
+        """
+        # TODO: move to IPlugin?
+
+
 class IPlugin(zope.interface.Interface):
     """Let's Encrypt plugin."""
 
diff --git a/letsencrypt/client/plugins/apache/configurator.py b/letsencrypt/client/plugins/apache/configurator.py
index 55f7e2875..34a57b2b0 100644
--- a/letsencrypt/client/plugins/apache/configurator.py
+++ b/letsencrypt/client/plugins/apache/configurator.py
@@ -79,6 +79,7 @@ class ApacheConfigurator(augeas_configurator.AugeasConfigurator):
 
     """
     zope.interface.implements(interfaces.IAuthenticator, interfaces.IInstaller)
+    zope.interface.classProvides(interfaces.IPluginFactory)
 
     description = "Apache Web Server"
 
diff --git a/letsencrypt/client/plugins/standalone/authenticator.py b/letsencrypt/client/plugins/standalone/authenticator.py
index e0b06aa30..fa4e62d7f 100644
--- a/letsencrypt/client/plugins/standalone/authenticator.py
+++ b/letsencrypt/client/plugins/standalone/authenticator.py
@@ -30,9 +30,14 @@ class StandaloneAuthenticator(object):
 
     """
     zope.interface.implements(interfaces.IAuthenticator)
+    zope.interface.classProvides(interfaces.IPluginFactory)
 
     description = "Standalone Authenticator"
 
+    @classmethod
+    def add_parser_arguments(cls, add):
+        pass
+
     def __init__(self, unused_config):
         self.child_pid = None
         self.parent_pid = os.getpid()