diff --git a/cs/src/comm/epoxy-transport/EpoxyTransport.bond b/cs/src/comm/epoxy-transport/EpoxyTransport.bond
index 9c43253c78..7b1473f4a3 100644
--- a/cs/src/comm/epoxy-transport/EpoxyTransport.bond
+++ b/cs/src/comm/epoxy-transport/EpoxyTransport.bond
@@ -19,7 +19,7 @@ enum PayloadType
 struct EpoxyHeaders
 {
     0: uint64 conversation_id;
-    1: required PayloadType payload_type;
+    1: required PayloadType payload_type = Request;
     2: string method_name;
     3: int32 error_code;
 }
@@ -64,6 +64,6 @@ enum ProtocolErrorCode
 
 struct ProtocolError
 {
-    0: ProtocolErrorCode error_code;
+    0: ProtocolErrorCode error_code = GENERIC_ERROR;
     1: nullable<bonded<bond.comm.Error>> details;
 }
diff --git a/cs/src/comm/interfaces/Comm.bond b/cs/src/comm/interfaces/Comm.bond
index b086b45f0a..da9e0621ed 100644
--- a/cs/src/comm/interfaces/Comm.bond
+++ b/cs/src/comm/interfaces/Comm.bond
@@ -49,7 +49,7 @@ struct ConnectionMetrics
     0: string connection_id;
     1: string local_endpoint;
     2: string remote_endpoint;
-    3: ConnectionShutdownReason shutdown_reason;
+    3: ConnectionShutdownReason shutdown_reason = Unknown;
     4: double duration_millis;
 }
 
diff --git a/examples/cs/core/import/schema.bond b/examples/cs/core/import/schema.bond
index 36f31002f4..f6d8aa2c8c 100644
--- a/examples/cs/core/import/schema.bond
+++ b/examples/cs/core/import/schema.bond
@@ -7,6 +7,6 @@ struct Message
 {
     // To use a type from a different namespace, use its fully qualified name.
     0: Examples.Common.Protocol.Header Header;
-    1: Examples.Common.Priority Priority;
+    1: Examples.Common.Priority Priority = Normal;
     2: uint32 MessagePayload;
 }