diff --git a/test/setup.ts b/test/setup.ts
index c02df22be..0af5a6299 100644
--- a/test/setup.ts
+++ b/test/setup.ts
@@ -2,58 +2,9 @@ import fs from "node:fs";
 import os from "node:os";
 import path from "node:path";
 
-function sanitizeWindowsCIOutput(text: string): string {
-  return text
-    .replace(/[\uD800-\uDBFF][\uDC00-\uDFFF]/g, "?")
-    .replace(/[\uD800-\uDFFF]/g, "?");
-}
+import { installWindowsCIOutputSanitizer } from "./windows-ci-output-sanitizer";
 
-if (process.platform === "win32" && process.env.GITHUB_ACTIONS === "true") {
-  const decodeUtf8Text = (chunk: unknown): string | null => {
-    if (typeof chunk === "string") return chunk;
-    if (Buffer.isBuffer(chunk)) return chunk.toString("utf-8");
-    if (chunk instanceof Uint8Array)
-      return Buffer.from(chunk).toString("utf-8");
-    if (chunk instanceof ArrayBuffer)
-      return Buffer.from(chunk).toString("utf-8");
-    if (ArrayBuffer.isView(chunk)) {
-      return Buffer.from(
-        chunk.buffer,
-        chunk.byteOffset,
-        chunk.byteLength,
-      ).toString("utf-8");
-    }
-    return null;
-  };
-
-  const originalStdoutWrite = process.stdout.write.bind(process.stdout);
-  const originalStderrWrite = process.stderr.write.bind(process.stderr);
-
-  process.stdout.write = ((chunk: unknown, ...args: unknown[]) => {
-    const text = decodeUtf8Text(chunk);
-    if (text !== null)
-      return originalStdoutWrite(sanitizeWindowsCIOutput(text), ...args);
-    return originalStdoutWrite(chunk as never, ...args); // passthrough
-  }) as typeof process.stdout.write;
-
-  process.stderr.write = ((chunk: unknown, ...args: unknown[]) => {
-    const text = decodeUtf8Text(chunk);
-    if (text !== null)
-      return originalStderrWrite(sanitizeWindowsCIOutput(text), ...args);
-    return originalStderrWrite(chunk as never, ...args); // passthrough
-  }) as typeof process.stderr.write;
-
-  const originalWriteSync = fs.writeSync.bind(fs);
-  fs.writeSync = ((fd: number, data: unknown, ...args: unknown[]) => {
-    if (fd === 1 || fd === 2) {
-      const text = decodeUtf8Text(data);
-      if (text !== null) {
-        return originalWriteSync(fd, sanitizeWindowsCIOutput(text), ...args);
-      }
-    }
-    return originalWriteSync(fd, data as never, ...(args as never[]));
-  }) as typeof fs.writeSync;
-}
+installWindowsCIOutputSanitizer();
 
 const originalHome = process.env.HOME;
 const originalUserProfile = process.env.USERPROFILE;
diff --git a/test/vitest-global-setup.ts b/test/vitest-global-setup.ts
new file mode 100644
index 000000000..3a05d7661
--- /dev/null
+++ b/test/vitest-global-setup.ts
@@ -0,0 +1,5 @@
+import { installWindowsCIOutputSanitizer } from "./windows-ci-output-sanitizer";
+
+export default function globalSetup() {
+  installWindowsCIOutputSanitizer();
+}
diff --git a/test/windows-ci-output-sanitizer.ts b/test/windows-ci-output-sanitizer.ts
new file mode 100644
index 000000000..37c777d4f
--- /dev/null
+++ b/test/windows-ci-output-sanitizer.ts
@@ -0,0 +1,59 @@
+import fs from "node:fs";
+
+function sanitizeWindowsCIOutput(text: string): string {
+  return text
+    .replace(/[\uD800-\uDBFF][\uDC00-\uDFFF]/g, "?")
+    .replace(/[\uD800-\uDFFF]/g, "?");
+}
+
+function decodeUtf8Text(chunk: unknown): string | null {
+  if (typeof chunk === "string") return chunk;
+  if (Buffer.isBuffer(chunk)) return chunk.toString("utf-8");
+  if (chunk instanceof Uint8Array) return Buffer.from(chunk).toString("utf-8");
+  if (chunk instanceof ArrayBuffer) return Buffer.from(chunk).toString("utf-8");
+  if (ArrayBuffer.isView(chunk)) {
+    return Buffer.from(
+      chunk.buffer,
+      chunk.byteOffset,
+      chunk.byteLength,
+    ).toString("utf-8");
+  }
+  return null;
+}
+
+export function installWindowsCIOutputSanitizer(): void {
+  if (process.platform !== "win32") return;
+  if (process.env.GITHUB_ACTIONS !== "true") return;
+
+  const globalKey = "__clawdbotWindowsCIOutputSanitizerInstalled";
+  if ((globalThis as Record<string, unknown>)[globalKey] === true) return;
+  (globalThis as Record<string, unknown>)[globalKey] = true;
+
+  const originalStdoutWrite = process.stdout.write.bind(process.stdout);
+  const originalStderrWrite = process.stderr.write.bind(process.stderr);
+
+  process.stdout.write = ((chunk: unknown, ...args: unknown[]) => {
+    const text = decodeUtf8Text(chunk);
+    if (text !== null)
+      return originalStdoutWrite(sanitizeWindowsCIOutput(text), ...args);
+    return originalStdoutWrite(chunk as never, ...args); // passthrough
+  }) as typeof process.stdout.write;
+
+  process.stderr.write = ((chunk: unknown, ...args: unknown[]) => {
+    const text = decodeUtf8Text(chunk);
+    if (text !== null)
+      return originalStderrWrite(sanitizeWindowsCIOutput(text), ...args);
+    return originalStderrWrite(chunk as never, ...args); // passthrough
+  }) as typeof process.stderr.write;
+
+  const originalWriteSync = fs.writeSync.bind(fs);
+  fs.writeSync = ((fd: number, data: unknown, ...args: unknown[]) => {
+    if (fd === 1 || fd === 2) {
+      const text = decodeUtf8Text(data);
+      if (text !== null) {
+        return originalWriteSync(fd, sanitizeWindowsCIOutput(text), ...args);
+      }
+    }
+    return originalWriteSync(fd, data as never, ...(args as never[]));
+  }) as typeof fs.writeSync;
+}
diff --git a/vitest.config.ts b/vitest.config.ts
index 87f83935f..f2d9ca1a2 100644
--- a/vitest.config.ts
+++ b/vitest.config.ts
@@ -4,6 +4,7 @@ export default defineConfig({
   test: {
     include: ["src/**/*.test.ts", "test/format-error.test.ts"],
     setupFiles: ["test/setup.ts"],
+    globalSetup: ["test/vitest-global-setup.ts"],
     exclude: [
       "dist/**",
       "apps/macos/**",