diff --git a/apps/emqx/src/emqx_channel.erl b/apps/emqx/src/emqx_channel.erl
index a3480e232..1f51c15b1 100644
--- a/apps/emqx/src/emqx_channel.erl
+++ b/apps/emqx/src/emqx_channel.erl
@@ -259,7 +259,8 @@ init(
             mountpoint => MountPoint,
             is_bridge => false,
             is_superuser => false,
-            enable_authn => maps:get(enable_authn, Opts, true)
+            enable_authn => maps:get(enable_authn, Opts, true),
+            attrs => #{}
         },
         Zone
     ),
diff --git a/apps/emqx/src/emqx_cm.erl b/apps/emqx/src/emqx_cm.erl
index c14058f9a..ac41c2da4 100644
--- a/apps/emqx/src/emqx_cm.erl
+++ b/apps/emqx/src/emqx_cm.erl
@@ -221,7 +221,7 @@ get_chan_info(ClientId, ChanPid) ->
     wrap_rpc(emqx_cm_proto_v2:get_chan_info(ClientId, ChanPid)).
 
 %% @doc Update infos of the channel.
--spec set_chan_info(emqx_types:clientid(), emqx_types:attrs()) -> boolean().
+-spec set_chan_info(emqx_types:clientid(), emqx_types:channel_attrs()) -> boolean().
 set_chan_info(ClientId, Info) when ?IS_CLIENTID(ClientId) ->
     Chan = {ClientId, self()},
     try
diff --git a/apps/emqx/src/emqx_types.erl b/apps/emqx/src/emqx_types.erl
index 99a71e20b..3883991b4 100644
--- a/apps/emqx/src/emqx_types.erl
+++ b/apps/emqx/src/emqx_types.erl
@@ -54,7 +54,8 @@
     password/0,
     peerhost/0,
     peername/0,
-    protocol/0
+    protocol/0,
+    client_attrs/0
 ]).
 
 -export_type([
@@ -106,7 +107,7 @@
 
 -export_type([
     caps/0,
-    attrs/0,
+    channel_attrs/0,
     infos/0,
     stats/0
 ]).
@@ -189,8 +190,11 @@
     anonymous => boolean(),
     cn => binary(),
     dn => binary(),
+    %% extra attributes
+    attrs => client_attrs(),
     atom() => term()
 }.
+-type client_attrs() :: #{binary() => binary()}.
 -type clientid() :: binary() | atom().
 -type username() :: option(binary()).
 -type password() :: option(binary()).
@@ -270,7 +274,7 @@
 -type command() :: #command{}.
 
 -type caps() :: emqx_mqtt_caps:caps().
--type attrs() :: #{atom() => term()}.
+-type channel_attrs() :: #{atom() => term()}.
 -type infos() :: #{atom() => term()}.
 -type stats() :: [{atom(), term()}].