diff --git a/pkgs/by-name/st/stalwart_0_16/package.nix b/pkgs/by-name/st/stalwart_0_16/package.nix
index 311ba8536bb2..608ae1d9a6ab 100644
--- a/pkgs/by-name/st/stalwart_0_16/package.nix
+++ b/pkgs/by-name/st/stalwart_0_16/package.nix
@@ -112,6 +112,12 @@ rustPlatform.buildRustPackage (finalAttrs: {
   ++ lib.optionals withFoundationdb [ "foundationdb" ]
   ++ lib.optionals stalwartEnterprise [ "enterprise" ];
 
+  cargoBuildFlags = [
+    "-p"
+    "stalwart"
+  ];
+  cargoTestFlags = finalAttrs.cargoBuildFlags;
+
   doCheck = true;
   nativeCheckInputs = [
     openssl