diff --git a/enjo_lib/comm/transport/datagrams.py b/enjo_lib/comm/transport/datagrams.py
index d46e7db..800b96c 100644
--- a/enjo_lib/comm/transport/datagrams.py
+++ b/enjo_lib/comm/transport/datagrams.py
@@ -99,6 +99,7 @@ class FailureMetadata(GeneralTransportMetadata):
 
     epoch: EpochId
     reason: HumanFriendlyDesc
+    debug_data: JSON
 
 
 # restart