diff --git a/hosts/bagel-box/default.nix b/hosts/bagel-box/default.nix
index 1560c2d..e09cb29 100644
--- a/hosts/bagel-box/default.nix
+++ b/hosts/bagel-box/default.nix
@@ -39,11 +39,8 @@
 
     hydra.enable = true;
     hydra.dbi = "dbi:Pg:dbname=hydra;user=hydra";
-
-    hydra.builders = [
-      "builder-0"
-      "builder-1"
-    ];
+    # Takes 10 builders (0 → 9).
+    hydra.builders = lib.genList (i: "builder-${i}") 9;
 
     ofborg.enable = true;
   };