diff --git a/tests/root-tsconfig.test.ts b/tests/root-tsconfig.test.ts
new file mode 100644
index 000000000..c0e532075
--- /dev/null
+++ b/tests/root-tsconfig.test.ts
@@ -0,0 +1,40 @@
+import path from "node:path";
+import ts from "typescript";
+import { describe, expect, it } from "vite-plus/test";
+
+const repoRoot = path.resolve(import.meta.dirname, "..");
+const rootTsconfig = path.join(repoRoot, "tsconfig.json");
+
+function loadRootTsconfigFileNames(): string[] {
+  const config = ts.readConfigFile(rootTsconfig, (fileName) => ts.sys.readFile(fileName));
+  if (config.error) {
+    throw new Error(ts.flattenDiagnosticMessageText(config.error.messageText, "\n"));
+  }
+
+  const parsed = ts.parseJsonConfigFileContent(config.config, ts.sys, repoRoot);
+  if (parsed.errors.length > 0) {
+    throw new Error(
+      parsed.errors
+        .map((error) => ts.flattenDiagnosticMessageText(error.messageText, "\n"))
+        .join("\n"),
+    );
+  }
+
+  return parsed.fileNames.map((fileName) =>
+    path.relative(repoRoot, fileName).replaceAll(path.sep, "/"),
+  );
+}
+
+describe("root tsconfig scope", () => {
+  it("keeps independent app files and package build output outside the root project", () => {
+    const fileNames = loadRootTsconfigFileNames();
+
+    expect(fileNames).toContain("packages/vinext/src/index.ts");
+    expect(fileNames).toContain("tests/root-tsconfig.test.ts");
+    expect(fileNames).toContain("vite.config.ts");
+    expect(fileNames.some((fileName) => fileName.startsWith("apps/"))).toBe(false);
+    expect(fileNames.some((fileName) => fileName.startsWith("packages/vinext/dist/"))).toBe(false);
+    expect(fileNames.some((fileName) => fileName.startsWith(".claude/"))).toBe(false);
+    expect(fileNames.some((fileName) => fileName.startsWith(".worktrees/"))).toBe(false);
+  });
+});
diff --git a/tsconfig.json b/tsconfig.json
index 9c8b4ae82..2879f6869 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -14,5 +14,13 @@
       "vinext/shims/*": ["./packages/vinext/src/shims/*"]
     }
   },
+  "include": [
+    "*.ts",
+    "*.tsx",
+    "packages/vinext/src/**/*.ts",
+    "packages/vinext/src/**/*.tsx",
+    "tests/**/*.ts",
+    "tests/**/*.tsx"
+  ],
   "exclude": ["node_modules", "dist", "fixtures", "tests/fixtures", "benchmarks", "examples"]
 }