diff --git a/tests/all-package-defaults.nix b/tests/all-package-defaults.nix
index b54c85a1..a822f6eb 100644
--- a/tests/all-package-defaults.nix
+++ b/tests/all-package-defaults.nix
@@ -75,6 +75,10 @@ let
     "rustaceanvim"
   ]
   ++ lib.optionals hostPlatform.isDarwin [
+    # 2026-04-09: OCaml toolchain build failure on Darwin
+    "flow"
+    "fstar"
+
     # 2026-04-09: build failure
     "fortitude"