diff --git a/pkgs/by-name/kc/kcl-language-server/package.nix b/pkgs/by-name/kc/kcl-language-server/package.nix
index 0a2c8c9ed034..375a89b3a8e4 100644
--- a/pkgs/by-name/kc/kcl-language-server/package.nix
+++ b/pkgs/by-name/kc/kcl-language-server/package.nix
@@ -22,8 +22,10 @@ rustPlatform.buildRustPackage (finalAttrs: {
 
   cargoHash = "sha256-FulW9qNVVZtOoRfm+NPwQENJU9Ib1GBzcjHxk5QS70g=";
 
-  PROTOC = "${protobuf}/bin/protoc";
-  PROTOC_INCLUDE = "${protobuf}/include";
+  env = {
+    PROTOC = "${protobuf}/bin/protoc";
+    PROTOC_INCLUDE = "${protobuf}/include";
+  };
 
   buildAndTestSubdir = "tools/src/LSP";