diff --git a/libs/line-message/commands/group.js b/libs/line-message/commands/group.js
index 8e44807..633aab2 100644
--- a/libs/line-message/commands/group.js
+++ b/libs/line-message/commands/group.js
@@ -187,6 +187,12 @@ const delPage = async (txt = '', source = {}, db) => {
   }
 }
 
+/**
+ * add twitch channel notify to group
+ * @param {string} txt command body format => twitch_user type tmpl
+ * @param {object} source
+ * @param {object} db
+ */
 const addTwitch = async (txt = '', source = {}, db) => {
   if (!db) return null
   if (!('type' in source) || !('groupId' in source) || !('userId' in source)) return null