diff --git a/pkgs/by-name/md/mdserve/package.nix b/pkgs/by-name/md/mdserve/package.nix
index 3e6ddf1b91c1..087e9ebae6f3 100644
--- a/pkgs/by-name/md/mdserve/package.nix
+++ b/pkgs/by-name/md/mdserve/package.nix
@@ -26,7 +26,7 @@ rustPlatform.buildRustPackage (finalAttrs: {
 
   checkFlags = lib.optionals stdenv.hostPlatform.isDarwin [
     # times out on darwin during nixpkgs-review
-    "--skip test_file_modification_updates_via_websocket"
+    "--skip=test_file_modification_updates_via_websocket"
   ];
 
   passthru.updateScript = nix-update-script { };