diff --git a/src/HomeAssistant/Runtime.hs b/src/HomeAssistant/Runtime.hs
index 8d58d8a..94d35a0 100644
--- a/src/HomeAssistant/Runtime.hs
+++ b/src/HomeAssistant/Runtime.hs
@@ -86,10 +86,10 @@ receiveJSON conn = do
 
 wsCallService
   :: WS.Connection
-  -> Int
-  -> T.Text
-  -> T.Text
-  -> T.Text
+  -> Int           -- ^ request id
+  -> T.Text        -- ^ domain
+  -> T.Text        -- ^ service
+  -> T.Text        -- ^ entity id
   -> IO ()
 wsCallService conn requestId domain service entityId =
   WS.sendTextData conn $ encode $ object