diff --git a/schema/druncschema/process_manager.proto b/schema/druncschema/process_manager.proto
index a51c6ac..0f85ebb 100644
--- a/schema/druncschema/process_manager.proto
+++ b/schema/druncschema/process_manager.proto
@@ -104,7 +104,7 @@ message ProcessInstance {
     DEAD = 1;
   };
   StatusCode status_code = 3;
-  int32 return_code = 4;
+  optional int32 return_code = 4;
   ProcessUUID uuid = 5;
   optional string remote_pid = 6;
 }
diff --git a/src/druncschema/process_manager_pb2.py b/src/druncschema/process_manager_pb2.py
index 41eebe0..8fcd377 100644
--- a/src/druncschema/process_manager_pb2.py
+++ b/src/druncschema/process_manager_pb2.py
@@ -28,7 +28,7 @@
 from druncschema import generic_pb2 as druncschema_dot_generic__pb2
 
 
-DESCRIPTOR = _descriptor_pool.Default().AddSerializedFile(b'\n!druncschema/process_manager.proto\x12#dunedaq.druncschema.process_manager\x1a\"druncschema/request_response.proto\x1a\x1d\x64runcschema/description.proto\x1a\x17\x64runcschema/token.proto\x1a\x19\x64runcschema/generic.proto\"o\n\x12ProcessRestriction\x12\x15\n\rallowed_hosts\x18\x01 \x03(\t\x12\x1a\n\x12\x61llowed_host_types\x18\x02 \x03(\t\x12\x17\n\ndata_mount\x18\x03 \x01(\tH\x00\x88\x01\x01\x42\r\n\x0b_data_mount\";\n\x1a\x43ommandNotificationMessage\x12\x0c\n\x04user\x18\x01 \x01(\t\x12\x0f\n\x07\x63ommand\x18\x02 \x01(\t\"-\n\x1aGenericNotificationMessage\x12\x0f\n\x07message\x18\x01 \x01(\t\"\xc9\x01\n\x15\x45xceptionNotification\x12\x12\n\nerror_text\x18\x01 \x01(\t\x12Y\n\x0bstack_trace\x18\x02 \x03(\x0b\x32\x44.dunedaq.druncschema.process_manager.ExceptionNotification.StackLine\x1a\x41\n\tStackLine\x12\x11\n\tline_text\x18\x01 \x01(\t\x12\x13\n\x0bline_number\x18\x02 \x01(\t\x12\x0c\n\x04\x66ile\x18\x03 \x01(\t\"\x8a\x01\n\nLogRequest\x12)\n\x05token\x18\x01 \x01(\x0b\x32\x1a.dunedaq.druncschema.Token\x12@\n\x05query\x18\x02 \x01(\x0b\x32\x31.dunedaq.druncschema.process_manager.ProcessQuery\x12\x0f\n\x07how_far\x18\x03 \x01(\x05\"\xc3\x01\n\x08LogLines\x12\x0c\n\x04name\x18\x01 \x01(\t\x12)\n\x05token\x18\x02 \x01(\x0b\x32\x1a.dunedaq.druncschema.Token\x12>\n\x04uuid\x18\x03 \x01(\x0b\x32\x30.dunedaq.druncschema.process_manager.ProcessUUID\x12\r\n\x05lines\x18\x04 \x03(\t\x12/\n\x04\x66lag\x18\x05 \x01(\x0e\x32!.dunedaq.druncschema.ResponseFlag\"\x1b\n\x0bProcessUUID\x12\x0c\n\x04uuid\x18\x01 \x01(\t\"\xc3\x01\n\x0fProcessMetadata\x12>\n\x04uuid\x18\x01 \x01(\x0b\x32\x30.dunedaq.druncschema.process_manager.ProcessUUID\x12\x0c\n\x04user\x18\x02 \x01(\t\x12\x14\n\x07session\x18\x03 \x01(\tH\x00\x88\x01\x01\x12\x0c\n\x04name\x18\x04 \x01(\t\x12\x10\n\x08hostname\x18\x05 \x01(\t\x12\x14\n\x07tree_id\x18\x06 \x01(\tH\x01\x88\x01\x01\x42\n\n\x08_sessionB\n\n\x08_tree_id\"\xc6\x01\n\x0cProcessQuery\x12)\n\x05token\x18\x01 \x01(\x0b\x32\x1a.dunedaq.druncschema.Token\x12?\n\x05uuids\x18\x02 \x03(\x0b\x32\x30.dunedaq.druncschema.process_manager.ProcessUUID\x12\r\n\x05names\x18\x03 \x03(\t\x12\x0c\n\x04user\x18\x04 \x01(\t\x12\x0f\n\x07session\x18\x05 \x01(\t\x12\x12\n\x05\x63rash\x18\x06 \x01(\x08H\x00\x88\x01\x01\x42\x08\n\x06_crash\"\xc7\x03\n\x12ProcessDescription\x12\x46\n\x08metadata\x18\x01 \x01(\x0b\x32\x34.dunedaq.druncschema.process_manager.ProcessMetadata\x12M\n\x03\x65nv\x18\x02 \x03(\x0b\x32@.dunedaq.druncschema.process_manager.ProcessDescription.EnvEntry\x12\x65\n\x18\x65xecutable_and_arguments\x18\x03 \x03(\x0b\x32\x43.dunedaq.druncschema.process_manager.ProcessDescription.ExecAndArgs\x12#\n\x1bprocess_execution_directory\x18\x04 \x01(\t\x12\x19\n\x11process_logs_path\x18\x05 \x01(\t\x1a\x1c\n\nStringList\x12\x0e\n\x06values\x18\x01 \x03(\t\x1a)\n\x0b\x45xecAndArgs\x12\x0c\n\x04\x65xec\x18\x01 \x01(\t\x12\x0c\n\x04\x61rgs\x18\x02 \x03(\t\x1a*\n\x08\x45nvEntry\x12\x0b\n\x03key\x18\x01 \x01(\t\x12\r\n\x05value\x18\x02 \x01(\t:\x02\x38\x01\"\xb5\x03\n\x0fProcessInstance\x12T\n\x13process_description\x18\x01 \x01(\x0b\x32\x37.dunedaq.druncschema.process_manager.ProcessDescription\x12T\n\x13process_restriction\x18\x02 \x01(\x0b\x32\x37.dunedaq.druncschema.process_manager.ProcessRestriction\x12T\n\x0bstatus_code\x18\x03 \x01(\x0e\x32?.dunedaq.druncschema.process_manager.ProcessInstance.StatusCode\x12\x13\n\x0breturn_code\x18\x04 \x01(\x05\x12>\n\x04uuid\x18\x05 \x01(\x0b\x32\x30.dunedaq.druncschema.process_manager.ProcessUUID\x12\x17\n\nremote_pid\x18\x06 \x01(\tH\x00\x88\x01\x01\"#\n\nStatusCode\x12\x0b\n\x07RUNNING\x10\x00\x12\x08\n\x04\x44\x45\x41\x44\x10\x01\x42\r\n\x0b_remote_pid\"\xc5\x01\n\x13ProcessInstanceList\x12\x0c\n\x04name\x18\x01 \x01(\t\x12)\n\x05token\x18\x02 \x01(\x0b\x32\x1a.dunedaq.druncschema.Token\x12\x44\n\x06values\x18\x03 \x03(\x0b\x32\x34.dunedaq.druncschema.process_manager.ProcessInstance\x12/\n\x04\x66lag\x18\x04 \x01(\x0e\x32!.dunedaq.druncschema.ResponseFlag\"\xe4\x01\n\x0b\x42ootRequest\x12)\n\x05token\x18\x01 \x01(\x0b\x32\x1a.dunedaq.druncschema.Token\x12T\n\x13process_description\x18\x02 \x01(\x0b\x32\x37.dunedaq.druncschema.process_manager.ProcessDescription\x12T\n\x13process_restriction\x18\x03 \x01(\x0b\x32\x37.dunedaq.druncschema.process_manager.ProcessRestriction2\xd3\x07\n\x0eProcessManager\x12N\n\x08send_msg\x12\x1c.dunedaq.druncschema.Request\x1a\".dunedaq.druncschema.OutcomeStatus\"\x00\x12L\n\x08\x64\x65scribe\x12\x1c.dunedaq.druncschema.Request\x1a .dunedaq.druncschema.Description\"\x00\x12t\n\x04\x62oot\x12\x30.dunedaq.druncschema.process_manager.BootRequest\x1a\x38.dunedaq.druncschema.process_manager.ProcessInstanceList\"\x00\x12\x65\n\tterminate\x12\x1c.dunedaq.druncschema.Request\x1a\x38.dunedaq.druncschema.process_manager.ProcessInstanceList\"\x00\x12x\n\x07restart\x12\x31.dunedaq.druncschema.process_manager.ProcessQuery\x1a\x38.dunedaq.druncschema.process_manager.ProcessInstanceList\"\x00\x12u\n\x04kill\x12\x31.dunedaq.druncschema.process_manager.ProcessQuery\x1a\x38.dunedaq.druncschema.process_manager.ProcessInstanceList\"\x00\x12v\n\x05\x66lush\x12\x31.dunedaq.druncschema.process_manager.ProcessQuery\x1a\x38.dunedaq.druncschema.process_manager.ProcessInstanceList\"\x00\x12s\n\x02ps\x12\x31.dunedaq.druncschema.process_manager.ProcessQuery\x1a\x38.dunedaq.druncschema.process_manager.ProcessInstanceList\"\x00\x12h\n\x04logs\x12/.dunedaq.druncschema.process_manager.LogRequest\x1a-.dunedaq.druncschema.process_manager.LogLines\"\x00\x62\x06proto3')
+DESCRIPTOR = _descriptor_pool.Default().AddSerializedFile(b'\n!druncschema/process_manager.proto\x12#dunedaq.druncschema.process_manager\x1a\"druncschema/request_response.proto\x1a\x1d\x64runcschema/description.proto\x1a\x17\x64runcschema/token.proto\x1a\x19\x64runcschema/generic.proto\"o\n\x12ProcessRestriction\x12\x15\n\rallowed_hosts\x18\x01 \x03(\t\x12\x1a\n\x12\x61llowed_host_types\x18\x02 \x03(\t\x12\x17\n\ndata_mount\x18\x03 \x01(\tH\x00\x88\x01\x01\x42\r\n\x0b_data_mount\";\n\x1a\x43ommandNotificationMessage\x12\x0c\n\x04user\x18\x01 \x01(\t\x12\x0f\n\x07\x63ommand\x18\x02 \x01(\t\"-\n\x1aGenericNotificationMessage\x12\x0f\n\x07message\x18\x01 \x01(\t\"\xc9\x01\n\x15\x45xceptionNotification\x12\x12\n\nerror_text\x18\x01 \x01(\t\x12Y\n\x0bstack_trace\x18\x02 \x03(\x0b\x32\x44.dunedaq.druncschema.process_manager.ExceptionNotification.StackLine\x1a\x41\n\tStackLine\x12\x11\n\tline_text\x18\x01 \x01(\t\x12\x13\n\x0bline_number\x18\x02 \x01(\t\x12\x0c\n\x04\x66ile\x18\x03 \x01(\t\"\x8a\x01\n\nLogRequest\x12)\n\x05token\x18\x01 \x01(\x0b\x32\x1a.dunedaq.druncschema.Token\x12@\n\x05query\x18\x02 \x01(\x0b\x32\x31.dunedaq.druncschema.process_manager.ProcessQuery\x12\x0f\n\x07how_far\x18\x03 \x01(\x05\"\xc3\x01\n\x08LogLines\x12\x0c\n\x04name\x18\x01 \x01(\t\x12)\n\x05token\x18\x02 \x01(\x0b\x32\x1a.dunedaq.druncschema.Token\x12>\n\x04uuid\x18\x03 \x01(\x0b\x32\x30.dunedaq.druncschema.process_manager.ProcessUUID\x12\r\n\x05lines\x18\x04 \x03(\t\x12/\n\x04\x66lag\x18\x05 \x01(\x0e\x32!.dunedaq.druncschema.ResponseFlag\"\x1b\n\x0bProcessUUID\x12\x0c\n\x04uuid\x18\x01 \x01(\t\"\xc3\x01\n\x0fProcessMetadata\x12>\n\x04uuid\x18\x01 \x01(\x0b\x32\x30.dunedaq.druncschema.process_manager.ProcessUUID\x12\x0c\n\x04user\x18\x02 \x01(\t\x12\x14\n\x07session\x18\x03 \x01(\tH\x00\x88\x01\x01\x12\x0c\n\x04name\x18\x04 \x01(\t\x12\x10\n\x08hostname\x18\x05 \x01(\t\x12\x14\n\x07tree_id\x18\x06 \x01(\tH\x01\x88\x01\x01\x42\n\n\x08_sessionB\n\n\x08_tree_id\"\xc6\x01\n\x0cProcessQuery\x12)\n\x05token\x18\x01 \x01(\x0b\x32\x1a.dunedaq.druncschema.Token\x12?\n\x05uuids\x18\x02 \x03(\x0b\x32\x30.dunedaq.druncschema.process_manager.ProcessUUID\x12\r\n\x05names\x18\x03 \x03(\t\x12\x0c\n\x04user\x18\x04 \x01(\t\x12\x0f\n\x07session\x18\x05 \x01(\t\x12\x12\n\x05\x63rash\x18\x06 \x01(\x08H\x00\x88\x01\x01\x42\x08\n\x06_crash\"\xc7\x03\n\x12ProcessDescription\x12\x46\n\x08metadata\x18\x01 \x01(\x0b\x32\x34.dunedaq.druncschema.process_manager.ProcessMetadata\x12M\n\x03\x65nv\x18\x02 \x03(\x0b\x32@.dunedaq.druncschema.process_manager.ProcessDescription.EnvEntry\x12\x65\n\x18\x65xecutable_and_arguments\x18\x03 \x03(\x0b\x32\x43.dunedaq.druncschema.process_manager.ProcessDescription.ExecAndArgs\x12#\n\x1bprocess_execution_directory\x18\x04 \x01(\t\x12\x19\n\x11process_logs_path\x18\x05 \x01(\t\x1a\x1c\n\nStringList\x12\x0e\n\x06values\x18\x01 \x03(\t\x1a)\n\x0b\x45xecAndArgs\x12\x0c\n\x04\x65xec\x18\x01 \x01(\t\x12\x0c\n\x04\x61rgs\x18\x02 \x03(\t\x1a*\n\x08\x45nvEntry\x12\x0b\n\x03key\x18\x01 \x01(\t\x12\r\n\x05value\x18\x02 \x01(\t:\x02\x38\x01\"\xca\x03\n\x0fProcessInstance\x12T\n\x13process_description\x18\x01 \x01(\x0b\x32\x37.dunedaq.druncschema.process_manager.ProcessDescription\x12T\n\x13process_restriction\x18\x02 \x01(\x0b\x32\x37.dunedaq.druncschema.process_manager.ProcessRestriction\x12T\n\x0bstatus_code\x18\x03 \x01(\x0e\x32?.dunedaq.druncschema.process_manager.ProcessInstance.StatusCode\x12\x18\n\x0breturn_code\x18\x04 \x01(\x05H\x00\x88\x01\x01\x12>\n\x04uuid\x18\x05 \x01(\x0b\x32\x30.dunedaq.druncschema.process_manager.ProcessUUID\x12\x17\n\nremote_pid\x18\x06 \x01(\tH\x01\x88\x01\x01\"#\n\nStatusCode\x12\x0b\n\x07RUNNING\x10\x00\x12\x08\n\x04\x44\x45\x41\x44\x10\x01\x42\x0e\n\x0c_return_codeB\r\n\x0b_remote_pid\"\xc5\x01\n\x13ProcessInstanceList\x12\x0c\n\x04name\x18\x01 \x01(\t\x12)\n\x05token\x18\x02 \x01(\x0b\x32\x1a.dunedaq.druncschema.Token\x12\x44\n\x06values\x18\x03 \x03(\x0b\x32\x34.dunedaq.druncschema.process_manager.ProcessInstance\x12/\n\x04\x66lag\x18\x04 \x01(\x0e\x32!.dunedaq.druncschema.ResponseFlag\"\xe4\x01\n\x0b\x42ootRequest\x12)\n\x05token\x18\x01 \x01(\x0b\x32\x1a.dunedaq.druncschema.Token\x12T\n\x13process_description\x18\x02 \x01(\x0b\x32\x37.dunedaq.druncschema.process_manager.ProcessDescription\x12T\n\x13process_restriction\x18\x03 \x01(\x0b\x32\x37.dunedaq.druncschema.process_manager.ProcessRestriction2\xd3\x07\n\x0eProcessManager\x12N\n\x08send_msg\x12\x1c.dunedaq.druncschema.Request\x1a\".dunedaq.druncschema.OutcomeStatus\"\x00\x12L\n\x08\x64\x65scribe\x12\x1c.dunedaq.druncschema.Request\x1a .dunedaq.druncschema.Description\"\x00\x12t\n\x04\x62oot\x12\x30.dunedaq.druncschema.process_manager.BootRequest\x1a\x38.dunedaq.druncschema.process_manager.ProcessInstanceList\"\x00\x12\x65\n\tterminate\x12\x1c.dunedaq.druncschema.Request\x1a\x38.dunedaq.druncschema.process_manager.ProcessInstanceList\"\x00\x12x\n\x07restart\x12\x31.dunedaq.druncschema.process_manager.ProcessQuery\x1a\x38.dunedaq.druncschema.process_manager.ProcessInstanceList\"\x00\x12u\n\x04kill\x12\x31.dunedaq.druncschema.process_manager.ProcessQuery\x1a\x38.dunedaq.druncschema.process_manager.ProcessInstanceList\"\x00\x12v\n\x05\x66lush\x12\x31.dunedaq.druncschema.process_manager.ProcessQuery\x1a\x38.dunedaq.druncschema.process_manager.ProcessInstanceList\"\x00\x12s\n\x02ps\x12\x31.dunedaq.druncschema.process_manager.ProcessQuery\x1a\x38.dunedaq.druncschema.process_manager.ProcessInstanceList\"\x00\x12h\n\x04logs\x12/.dunedaq.druncschema.process_manager.LogRequest\x1a-.dunedaq.druncschema.process_manager.LogLines\"\x00\x62\x06proto3')
 
 _globals = globals()
 _builder.BuildMessageAndEnumDescriptors(DESCRIPTOR, _globals)
@@ -66,13 +66,13 @@
   _globals['_PROCESSDESCRIPTION_ENVENTRY']._serialized_start=1799
   _globals['_PROCESSDESCRIPTION_ENVENTRY']._serialized_end=1841
   _globals['_PROCESSINSTANCE']._serialized_start=1844
-  _globals['_PROCESSINSTANCE']._serialized_end=2281
-  _globals['_PROCESSINSTANCE_STATUSCODE']._serialized_start=2231
-  _globals['_PROCESSINSTANCE_STATUSCODE']._serialized_end=2266
-  _globals['_PROCESSINSTANCELIST']._serialized_start=2284
-  _globals['_PROCESSINSTANCELIST']._serialized_end=2481
-  _globals['_BOOTREQUEST']._serialized_start=2484
-  _globals['_BOOTREQUEST']._serialized_end=2712
-  _globals['_PROCESSMANAGER']._serialized_start=2715
-  _globals['_PROCESSMANAGER']._serialized_end=3694
+  _globals['_PROCESSINSTANCE']._serialized_end=2302
+  _globals['_PROCESSINSTANCE_STATUSCODE']._serialized_start=2236
+  _globals['_PROCESSINSTANCE_STATUSCODE']._serialized_end=2271
+  _globals['_PROCESSINSTANCELIST']._serialized_start=2305
+  _globals['_PROCESSINSTANCELIST']._serialized_end=2502
+  _globals['_BOOTREQUEST']._serialized_start=2505
+  _globals['_BOOTREQUEST']._serialized_end=2733
+  _globals['_PROCESSMANAGER']._serialized_start=2736
+  _globals['_PROCESSMANAGER']._serialized_end=3715
 # @@protoc_insertion_point(module_scope)
diff --git a/src/druncschema/process_manager_pb2.pyi b/src/druncschema/process_manager_pb2.pyi
index 67c12ec..40e70d1 100644
--- a/src/druncschema/process_manager_pb2.pyi
+++ b/src/druncschema/process_manager_pb2.pyi
@@ -430,17 +430,22 @@ class ProcessInstance(_message.Message):
         process_description: Global___ProcessDescription | None = ...,
         process_restriction: Global___ProcessRestriction | None = ...,
         status_code: Global___ProcessInstance.StatusCode.ValueType = ...,
-        return_code: _builtins.int = ...,
+        return_code: _builtins.int | None = ...,
         uuid: Global___ProcessUUID | None = ...,
         remote_pid: _builtins.str | None = ...,
     ) -> None: ...
-    _HasFieldArgType: _TypeAlias = _typing.Literal["_remote_pid", b"_remote_pid", "process_description", b"process_description", "process_restriction", b"process_restriction", "remote_pid", b"remote_pid", "uuid", b"uuid"]  # noqa: Y015
+    _HasFieldArgType: _TypeAlias = _typing.Literal["_remote_pid", b"_remote_pid", "_return_code", b"_return_code", "process_description", b"process_description", "process_restriction", b"process_restriction", "remote_pid", b"remote_pid", "return_code", b"return_code", "uuid", b"uuid"]  # noqa: Y015
     def HasField(self, field_name: _HasFieldArgType) -> _builtins.bool: ...
-    _ClearFieldArgType: _TypeAlias = _typing.Literal["_remote_pid", b"_remote_pid", "process_description", b"process_description", "process_restriction", b"process_restriction", "remote_pid", b"remote_pid", "return_code", b"return_code", "status_code", b"status_code", "uuid", b"uuid"]  # noqa: Y015
+    _ClearFieldArgType: _TypeAlias = _typing.Literal["_remote_pid", b"_remote_pid", "_return_code", b"_return_code", "process_description", b"process_description", "process_restriction", b"process_restriction", "remote_pid", b"remote_pid", "return_code", b"return_code", "status_code", b"status_code", "uuid", b"uuid"]  # noqa: Y015
     def ClearField(self, field_name: _ClearFieldArgType) -> None: ...
     _WhichOneofReturnType__remote_pid: _TypeAlias = _typing.Literal["remote_pid"]  # noqa: Y015
     _WhichOneofArgType__remote_pid: _TypeAlias = _typing.Literal["_remote_pid", b"_remote_pid"]  # noqa: Y015
+    _WhichOneofReturnType__return_code: _TypeAlias = _typing.Literal["return_code"]  # noqa: Y015
+    _WhichOneofArgType__return_code: _TypeAlias = _typing.Literal["_return_code", b"_return_code"]  # noqa: Y015
+    @_typing.overload
     def WhichOneof(self, oneof_group: _WhichOneofArgType__remote_pid) -> _WhichOneofReturnType__remote_pid | None: ...
+    @_typing.overload
+    def WhichOneof(self, oneof_group: _WhichOneofArgType__return_code) -> _WhichOneofReturnType__return_code | None: ...
 
 Global___ProcessInstance: _TypeAlias = ProcessInstance  # noqa: Y015