diff --git a/lib/cdist/core/manifest.py b/lib/cdist/core/manifest.py
index f7b08c20..38d2ee98 100644
--- a/lib/cdist/core/manifest.py
+++ b/lib/cdist/core/manifest.py
@@ -75,7 +75,7 @@ class Manifest(object):
             '__cdist_type_base_path': self.local.type_path, # for use in type emulator
         }
         if self.log.getEffectiveLevel() == logging.DEBUG:
-            self.env.update({'__debug': "yes" })
+            self.env.update({'__cdist_debug': "yes" })
 
 
     def run_initial_manifest(self, script):