diff --git a/homeassistant/components/conversation.py b/homeassistant/components/conversation.py
index 11e018846c2..dc8446412c4 100644
--- a/homeassistant/components/conversation.py
+++ b/homeassistant/components/conversation.py
@@ -8,9 +8,12 @@ import logging
 import re
 import warnings
 
+import voluptuous as vol
+
 from homeassistant import core
 from homeassistant.const import (
     ATTR_ENTITY_ID, SERVICE_TURN_OFF, SERVICE_TURN_ON)
+import homeassistant.helpers.config_validation as cv
 
 DOMAIN = "conversation"
 
@@ -18,6 +21,10 @@ SERVICE_PROCESS = "process"
 
 ATTR_TEXT = "text"
 
+SERVICE_PROCESS_SCHEMA = vol.Schema({
+    vol.Required(ATTR_TEXT): vol.All(cv.string, vol.Lower),
+})
+
 REGEX_TURN_COMMAND = re.compile(r'turn (?P<name>(?: |\w)+) (?P<command>\w+)')
 
 REQUIREMENTS = ['fuzzywuzzy==0.8.0']
@@ -32,11 +39,7 @@ def setup(hass, config):
 
     def process(service):
         """Parse text into commands."""
-        if ATTR_TEXT not in service.data:
-            logger.error("Received process service call without a text")
-            return
-
-        text = service.data[ATTR_TEXT].lower()
+        text = service.data[ATTR_TEXT]
         match = REGEX_TURN_COMMAND.match(text)
 
         if not match:
@@ -67,6 +70,6 @@ def setup(hass, config):
             logger.error(
                 'Got unsupported command %s from text %s', command, text)
 
-    hass.services.register(DOMAIN, SERVICE_PROCESS, process)
-
+    hass.services.register(DOMAIN, SERVICE_PROCESS, process,
+                           schema=SERVICE_PROCESS_SCHEMA)
     return True