---- Update balance ---
-c ADD <user> <ammount> "<reason>"\n
-s 200 Add OK\n or 403 Not Coke\n or 404 Bad User\n
---- Set Balance ---
-c SET <user> <balance> "<reason>"\n
-s 200 Set OK\n or 403 Not allowed\n or 404 Bad User\n
---- Get Users Balances ---
-c ENUM_USERS[ <max balance>]\n
-s 201 Users <count> <username> <username> ...\n
+--- Alter balance ---
+c ADD <user> <ammount> <reason>\n
+s 200 Add OK\n or 402 No balance\n or 403 Not Coke\n or 404 Bad User\n
+
+--- Get Item list ---
+c ENUM_ITEMS\n
+s 201 Items <count>\n
+s 202 Item <item_id> <price> <description>\n
+ ...
+s 200 List End\n
+--- Get Item Information ---
+c ITEM_INFO <item_id>\n
+s 202 Item <item_id> <price> <description>\n
+
+--- Get Users' Balances ---
+ <max balance> and <min balance> can be '-' to indicate "none"
+c ENUM_USERS[ <min balance> [<max balance>]]\n
+s 201 Users <count>\n
+s 202 User <username> <balance> <flags>\n
+ ...
+s 200 List End\n