diff --git a/pkgs/tools/package-management/lix/common-lix.nix b/pkgs/tools/package-management/lix/common-lix.nix
index fdd550e8c8d1..42c3bc93e405 100644
--- a/pkgs/tools/package-management/lix/common-lix.nix
+++ b/pkgs/tools/package-management/lix/common-lix.nix
@@ -122,10 +122,11 @@ let
           [project options]
           builtin-dep-closure = @deps@
         '';
-        passAsFile = [ "input" ];
+        __structuredAttrs = true;
       }
       ''
-        substitute $inputPath $out --replace-fail @deps@ "$(cat ${deps})"
+        printf "%s" "$input" > $out
+        substituteInPlace $out --replace-fail @deps@ "$(cat ${deps})"
       '';
 
   # curl 8.21.0 /somehow/ breaks Lix unit tests.