diff --git a/launch/tf-env.nix b/launch/tf-env.nix
index 9ef8518a..fca0731d 100644
--- a/launch/tf-env.nix
+++ b/launch/tf-env.nix
@@ -6,7 +6,12 @@
 }:
 pkgs.stdenv.mkDerivation {
   name = "tf-repo";
-  src = ../.;
+  src =
+    with lib.fileset;
+    toSource {
+      root = ../.;
+      fileset = intersection (gitTracked ../.) ../.;
+    };
   buildInputs = [
     (import ./tf.nix { inherit lib pkgs; })
   ];