diff --git a/config.pbtxt b/config.pbtxt
index a738e22..0e4b12d 100644
--- a/config.pbtxt
+++ b/config.pbtxt
@@ -3,9 +3,19 @@ backend: "python"
 max_batch_size: 0
 
 input [
+  {
+    name: "INPUT"
+    data_type: TYPE_STRING
+    dims: [ -1 ]
+  }
 ]
 
 output [
+  {
+    name: "OUTPUT"
+    data_type: TYPE_STRING
+    dims: [ -1 ]
+  }
 ]