diff --git a/scripts/test-parallel.mjs b/scripts/test-parallel.mjs
index a98e0b11c3..cfa80dfa87 100644
--- a/scripts/test-parallel.mjs
+++ b/scripts/test-parallel.mjs
@@ -35,7 +35,10 @@ const isMacOS = process.platform === "darwin" || process.env.RUNNER_OS === "macO
 const isWindows = process.platform === "win32" || process.env.RUNNER_OS === "Windows";
 const isWindowsCi = isCI && isWindows;
 const nodeMajor = Number.parseInt(process.versions.node.split(".")[0] ?? "", 10);
-const supportsVmForks = Number.isFinite(nodeMajor) ? nodeMajor < 24 : true;
+// vmForks is a big win for transform/import heavy suites, but Node 24 had
+// regressions with Vitest's vm runtime in this repo. Keep it opt-out via
+// OPENCLAW_TEST_VM_FORKS=0, and let users force-enable with =1.
+const supportsVmForks = Number.isFinite(nodeMajor) ? nodeMajor !== 24 : true;
 const useVmForks =
   process.env.OPENCLAW_TEST_VM_FORKS === "1" ||
   (process.env.OPENCLAW_TEST_VM_FORKS !== "0" && !isWindows && supportsVmForks);
diff --git a/vitest.config.ts b/vitest.config.ts
index f5f35faaa8..7fc32c5c11 100644
--- a/vitest.config.ts
+++ b/vitest.config.ts
@@ -18,6 +18,9 @@ export default defineConfig({
   test: {
     testTimeout: 120_000,
     hookTimeout: isWindows ? 180_000 : 120_000,
+    // Many suites rely on `vi.stubEnv(...)` and expect it to be scoped to the test.
+    // This is especially important under `pool=vmForks` where env leaks cross-file.
+    unstubEnvs: true,
     pool: "forks",
     maxWorkers: isCI ? ciWorkers : localWorkers,
     include: ["src/**/*.test.ts", "extensions/**/*.test.ts", "test/format-error.test.ts"],