diff --git a/ops/nixos/marukuru/default.nix b/ops/nixos/marukuru/default.nix
index 59550546fe..fa0ef93098 100644
--- a/ops/nixos/marukuru/default.nix
+++ b/ops/nixos/marukuru/default.nix
@@ -201,6 +201,14 @@ in {
       shell = "/bin/sh";
       group = "phabricator";
     };
+    builder1 = {
+      isSystemUser = true;
+      hashedPassword = "";
+      shell = "/bin/sh";
+      openssh.authorizedKeys.keys = ["ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIIGXwDOm+ZwWNp97+W1cdzMCzfBzwP0CHt9lxPTSzomU"];
+      createHome = true;
+      home = "/home/builder1";
+    };
   };
   security.sudo.extraRules = [{
     users = [ "vcs" "anonvcs" ];