diff --git a/include/neuron/adapter.h b/include/neuron/adapter.h
index ee4523e0..567dc925 100644
--- a/include/neuron/adapter.h
+++ b/include/neuron/adapter.h
@@ -86,8 +86,8 @@ typedef struct adapter_callbacks {
 
     union {
         struct {
-            void (*update)(neu_adapter_t *adapter, const char *name,
-                           neu_dvalue_t value);
+            void (*update)(neu_adapter_t *adapter, const char *group,
+                           const char *tag, neu_dvalue_t value);
             void (*write_response)(neu_adapter_t *adapter, void *req,
                                    neu_error error);
         } driver;
diff --git a/include/neuron/plugin.h b/include/neuron/plugin.h
index cd2630ad..02d63424 100644
--- a/include/neuron/plugin.h
+++ b/include/neuron/plugin.h
@@ -50,6 +50,9 @@ struct neu_plugin_group {
     char *    group_name;
     UT_array *tags;
 
+    // the number of all tags under the node
+    uint16_t tag_size;
+
     void *                user_data;
     neu_plugin_group_free group_free;
 };