diff --git a/panel/default.nix b/panel/default.nix
index c6749611..9da9fef5 100644
--- a/panel/default.nix
+++ b/panel/default.nix
@@ -27,7 +27,7 @@ in
       pkgs.openssh
     ];
     env = {
-      DEPLOYMENT_FLAKE = ../.;
+      DEPLOYMENT_FLAKE = toString ../.;
       DEPLOYMENT_NAME = "test";
       NPINS_DIRECTORY = toString ../npins;
       CREDENTIALS_DIRECTORY = toString ./.credentials;