diff --git a/src/raspberrypi/rascsi_interface.proto b/src/raspberrypi/rascsi_interface.proto
index 92482fb5..1509a1f3 100644
--- a/src/raspberrypi/rascsi_interface.proto
+++ b/src/raspberrypi/rascsi_interface.proto
@@ -197,7 +197,8 @@ message PbOperationInfo {
     map<int32, PbOperationMetaData> operations = 1;
 }
 
-// rascsi special purpose error codes for cases where a textual error message is not sufficient
+// rascsi special purpose error codes for cases where a textual error message may not be not sufficient.
+/// The client may react on this code, e.g. by prompting the user for an authentication token.
 enum PbErrorCode {
     // No error code available
     NO_ERROR_CODE = 0;