diff --git a/MODULE.bazel b/MODULE.bazel
index 8163c0b018..3ac8e502fe 100644
--- a/MODULE.bazel
+++ b/MODULE.bazel
@@ -82,6 +82,7 @@ rules_rust = use_extension("@rules_rs//rs/experimental:rules_rust.bzl", "rules_r
 rules_rust.patch(
     patches = [
         "//patches:rules_rust_windows_gnullvm_build_script.patch",
+        "//patches:rules_rust_windows_nightly_gnu.patch",
     ],
     strip = 1,
 )
diff --git a/patches/rules_rust_windows_nightly_gnu.patch b/patches/rules_rust_windows_nightly_gnu.patch
new file mode 100644
index 0000000000..97bd540353
--- /dev/null
+++ b/patches/rules_rust_windows_nightly_gnu.patch
@@ -0,0 +1,20 @@
+# What: make the default rules_rust Windows nightly toolchain use GNU, not MSVC.
+# Why: codex's Bazel Windows platform is based on llvm-mingw/gnullvm, and the
+# nightly rustc-dev artifacts that power argument-comment-lint do not exist for
+# gnullvm. Using the default MSVC nightly toolchain on that platform mixes MSVC
+# Rust libraries with GNU/clang linker flags and breaks tool targets such as
+# `process_wrapper`.
+
+diff --git a/rust/repositories.bzl b/rust/repositories.bzl
+--- a/rust/repositories.bzl
++++ b/rust/repositories.bzl
+@@ -48,8 +48,8 @@ DEFAULT_TOOLCHAIN_TRIPLES = {
+     "aarch64-unknown-linux-gnu": "rust_linux_aarch64",
+     "powerpc64le-unknown-linux-gnu": "rust_linux_powerpc64le",
+     "s390x-unknown-linux-gnu": "rust_linux_s390x",
+     "x86_64-apple-darwin": "rust_macos_x86_64",
+-    "x86_64-pc-windows-msvc": "rust_windows_x86_64",
++    "x86_64-pc-windows-gnu": "rust_windows_x86_64",
+     "x86_64-unknown-freebsd": "rust_freebsd_x86_64",
+     "x86_64-unknown-linux-gnu": "rust_linux_x86_64",
+ }