diff --git a/frontend/src/uxbox/main/data/workspace.cljs b/frontend/src/uxbox/main/data/workspace.cljs
index b5f6f378a..88d8291a8 100644
--- a/frontend/src/uxbox/main/data/workspace.cljs
+++ b/frontend/src/uxbox/main/data/workspace.cljs
@@ -102,6 +102,8 @@
 (defn initialize
   "Initialize the workspace state."
   [project page]
+  {:pre [(uuid? project)
+         (uuid? page)]}
   (InitializeWorkspace. project page))
 
 ;; --- Workspace Tooltips