diff --git a/sway/ipc-json.c b/sway/ipc-json.c
index 3933f3ef7..3b69ad384 100644
--- a/sway/ipc-json.c
+++ b/sway/ipc-json.c
@@ -627,6 +627,9 @@ static void ipc_json_describe_view(struct sway_container *c, json_object *object
 	json_object_object_add(object, "sandbox_instance_id",
 			sandbox_instance_id ? json_object_new_string(sandbox_instance_id) : NULL);
 
+	const char *tag = view_get_tag(c->view);
+	json_object_object_add(object, "tag", tag ? json_object_new_string(tag) : NULL);
+
 	json_object *idle_inhibitors = json_object_new_object();
 
 	struct sway_idle_inhibitor_v1 *user_inhibitor =
diff --git a/sway/sway-ipc.7.scd b/sway/sway-ipc.7.scd
index 87f0828b7..4b0d5c962 100644
--- a/sway/sway-ipc.7.scd
+++ b/sway/sway-ipc.7.scd
@@ -419,6 +419,10 @@ node and will have the following properties:
 :  string
 :  (Only windows) The instance ID provided by the associated sandbox engine (or
    _null_)
+|- tag
+:  string
+:  (Only windows) For an xdg-shell window, tag of the toplevel, if set.
+   Otherwise, _null_
 |- window
 :  integer
 :  (Only xwayland windows) The X11 window ID for the xwayland window