diff --git a/src/main/java/org/broadinstitute/hellbender/utils/runtime/StreamingProcessController.java b/src/main/java/org/broadinstitute/hellbender/utils/runtime/StreamingProcessController.java
index f7e167d6384..18b8c16c82b 100644
--- a/src/main/java/org/broadinstitute/hellbender/utils/runtime/StreamingProcessController.java
+++ b/src/main/java/org/broadinstitute/hellbender/utils/runtime/StreamingProcessController.java
@@ -260,6 +260,7 @@ private ProcessControllerAckResult getNckWithMessageResult() throws IOException
             throw new GATKException("Negative ack message length  must be > 0");
         }
 
+        // now get the corresponding message of that length messageLength
         final String nckMessage = getIncomingMessage(messageLength);
         return new ProcessControllerAckResult(nckMessage);
     }
diff --git a/src/main/python/org/broadinstitute/hellbender/gatktool/tool.py b/src/main/python/org/broadinstitute/hellbender/gatktool/tool.py
index d7762cdc4c9..6997781f399 100644
--- a/src/main/python/org/broadinstitute/hellbender/gatktool/tool.py
+++ b/src/main/python/org/broadinstitute/hellbender/gatktool/tool.py
@@ -200,13 +200,13 @@ def writeNackWithMessage(self, message: str) -> None:
         self.fileWriter.write(toolconstants._nkmString)
         actualMessageLength = len(message)
         """The message length must be exactly 4 bytes"""
-        if len(str(actualMessageLength)) <= toolconstants.nckMessageLengthSerializedSize:
-            self.fileWriter.write(str(actualMessageLength).zfill(toolconstants.nckMessageLengthSerializedSize))
+        if len(str(actualMessageLength)) <= toolconstants._nckMessageLengthSerializedSize:
+            self.fileWriter.write(str(actualMessageLength).zfill(toolconstants._nckMessageLengthSerializedSize))
             self.fileWriter.write(message)
         else:
             """Message is too long, trim to 9999 bytes"""
-            self.fileWriter.write(str(toolconstants.nckMaxMessageLength))
-            self.fileWriter.write(message[:toolconstants.nckMaxMessageLength])
+            self.fileWriter.write(str(toolconstants._nckMaxMessageLength))
+            self.fileWriter.write(message[:toolconstants._nckMaxMessageLength])
         self.fileWriter.flush()