diff --git a/nixos/modules/services/continuous-integration/jenkins/default.nix b/nixos/modules/services/continuous-integration/jenkins/default.nix
index c3dc59a9fbd..b264a2e4bb4 100644
--- a/nixos/modules/services/continuous-integration/jenkins/default.nix
+++ b/nixos/modules/services/continuous-integration/jenkins/default.nix
@@ -25,7 +25,8 @@ in {
         default = "jenkins";
         type = with types; string;
         description = ''
-          User the jenkins server should execute under.
+          If the default user "jenkins" is configured then this is the primary
+          group of that user.
         '';
       };
 
diff --git a/nixos/modules/services/continuous-integration/jenkins/slave.nix b/nixos/modules/services/continuous-integration/jenkins/slave.nix
index 1d31ab830f6..9d952b2d2be 100644
--- a/nixos/modules/services/continuous-integration/jenkins/slave.nix
+++ b/nixos/modules/services/continuous-integration/jenkins/slave.nix
@@ -33,7 +33,8 @@ in {
         default = "jenkins";
         type = with types; string;
         description = ''
-          User the jenkins slave agent should execute under.
+          If the default slave agent user "jenkins" is configured then this is
+          the primary group of that user.
         '';
       };