diff --git a/src/calibre/utils/serve_coffee.py b/src/calibre/utils/serve_coffee.py
index 2493bcbba1..68bf9f5674 100644
--- a/src/calibre/utils/serve_coffee.py
+++ b/src/calibre/utils/serve_coffee.py
@@ -73,7 +73,7 @@ def fork_job(*args, **kwargs):
         except:
             errors = [traceback.format_exc()]
 
-        return cs, errors
+        return {'result':(cs, errors)}
 
 # }}}