diff --git a/common/nix-options.nix b/common/nix-options.nix
index dbcad26..11adb91 100644
--- a/common/nix-options.nix
+++ b/common/nix-options.nix
@@ -1,4 +1,4 @@
-{ lib, pkgs, ... }:
+{ config, lib, pkgs, ... }:
 
 {
   documentation = {
@@ -22,8 +22,7 @@
     log-lines = 32;
     # basically pwn-as-a-service
     accept-flake-config = false;
-    # set by `nix.registry.nixpkgs.flake`
-    flake-registry = "/etc/nix/registry.json";
+    flake-registry = config.nix.registry.nixpkgs.flake;
   };
 
   # Let <nixpkgs> be the used system packages, such that `nix-shell` can pick them up