diff --git a/ModeliRpc.proto b/ModeliRpc.proto
index 38552fdc569060af8385eb9d3deb840f06ab7a24..6c6b3cc274ec0533541315cc8da8b9a9d933dd81 100644
--- a/ModeliRpc.proto
+++ b/ModeliRpc.proto
@@ -78,6 +78,7 @@ message StopResponse {
 message AddFmuRequest {
     string instance_name = 1;
     bytes chunk = 2;
+    int64 total_size = 3;
 }
 
 message AddFmuResponse {