diff --git a/src/commands/doctor-session-locks.test.ts b/src/commands/doctor-session-locks.test.ts
index eb5a656a833..7a89b9437bf 100644
--- a/src/commands/doctor-session-locks.test.ts
+++ b/src/commands/doctor-session-locks.test.ts
@@ -2,6 +2,7 @@ import fs from "node:fs/promises";
 import os from "node:os";
 import path from "node:path";
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import { captureEnv } from "../test-utils/env.js";
 
 const note = vi.hoisted(() => vi.fn());
 
@@ -13,21 +14,17 @@ import { noteSessionLockHealth } from "./doctor-session-locks.js";
 
 describe("noteSessionLockHealth", () => {
   let root: string;
-  let prevStateDir: string | undefined;
+  let envSnapshot: ReturnType<typeof captureEnv>;
 
   beforeEach(async () => {
     note.mockReset();
-    prevStateDir = process.env.OPENCLAW_STATE_DIR;
+    envSnapshot = captureEnv(["OPENCLAW_STATE_DIR"]);
     root = await fs.mkdtemp(path.join(os.tmpdir(), "openclaw-doctor-locks-"));
     process.env.OPENCLAW_STATE_DIR = root;
   });
 
   afterEach(async () => {
-    if (prevStateDir === undefined) {
-      delete process.env.OPENCLAW_STATE_DIR;
-    } else {
-      process.env.OPENCLAW_STATE_DIR = prevStateDir;
-    }
+    envSnapshot.restore();
     await fs.rm(root, { recursive: true, force: true });
   });
 
diff --git a/src/infra/restart-sentinel.test.ts b/src/infra/restart-sentinel.test.ts
index a675617f948..ec97c8c5c15 100644
--- a/src/infra/restart-sentinel.test.ts
+++ b/src/infra/restart-sentinel.test.ts
@@ -2,6 +2,7 @@ import fs from "node:fs/promises";
 import os from "node:os";
 import path from "node:path";
 import { afterEach, beforeEach, describe, expect, it } from "vitest";
+import { captureEnv } from "../test-utils/env.js";
 import {
   consumeRestartSentinel,
   formatRestartSentinelMessage,
@@ -12,21 +13,17 @@ import {
 } from "./restart-sentinel.js";
 
 describe("restart sentinel", () => {
-  let prevStateDir: string | undefined;
+  let envSnapshot: ReturnType<typeof captureEnv>;
   let tempDir: string;
 
   beforeEach(async () => {
-    prevStateDir = process.env.OPENCLAW_STATE_DIR;
+    envSnapshot = captureEnv(["OPENCLAW_STATE_DIR"]);
     tempDir = await fs.mkdtemp(path.join(os.tmpdir(), "openclaw-sentinel-"));
     process.env.OPENCLAW_STATE_DIR = tempDir;
   });
 
   afterEach(async () => {
-    if (prevStateDir) {
-      process.env.OPENCLAW_STATE_DIR = prevStateDir;
-    } else {
-      delete process.env.OPENCLAW_STATE_DIR;
-    }
+    envSnapshot.restore();
     await fs.rm(tempDir, { recursive: true, force: true });
   });
 
diff --git a/src/infra/update-startup.test.ts b/src/infra/update-startup.test.ts
index cc88cc1ce7a..924740cdd33 100644
--- a/src/infra/update-startup.test.ts
+++ b/src/infra/update-startup.test.ts
@@ -2,6 +2,7 @@ import fs from "node:fs/promises";
 import os from "node:os";
 import path from "node:path";
 import { afterAll, afterEach, beforeAll, beforeEach, describe, expect, it, vi } from "vitest";
+import { captureEnv } from "../test-utils/env.js";
 import type { UpdateCheckResult } from "./update-check.js";
 
 vi.mock("./openclaw-root.js", () => ({
@@ -38,12 +39,7 @@ describe("update-startup", () => {
   let suiteRoot = "";
   let suiteCase = 0;
   let tempDir: string;
-  let prevStateDir: string | undefined;
-  let prevNodeEnv: string | undefined;
-  let prevVitest: string | undefined;
-  let hadStateDir = false;
-  let hadNodeEnv = false;
-  let hadVitest = false;
+  let envSnapshot: ReturnType<typeof captureEnv>;
 
   let resolveOpenClawPackageRoot: (typeof import("./openclaw-root.js"))["resolveOpenClawPackageRoot"];
   let checkUpdateStatus: (typeof import("./update-check.js"))["checkUpdateStatus"];
@@ -62,17 +58,12 @@ describe("update-startup", () => {
     vi.setSystemTime(new Date("2026-01-17T10:00:00Z"));
     tempDir = path.join(suiteRoot, `case-${++suiteCase}`);
     await fs.mkdir(tempDir);
-    hadStateDir = Object.prototype.hasOwnProperty.call(process.env, "OPENCLAW_STATE_DIR");
-    prevStateDir = process.env.OPENCLAW_STATE_DIR;
+    envSnapshot = captureEnv(["OPENCLAW_STATE_DIR", "NODE_ENV", "VITEST"]);
     process.env.OPENCLAW_STATE_DIR = tempDir;
 
-    hadNodeEnv = Object.prototype.hasOwnProperty.call(process.env, "NODE_ENV");
-    prevNodeEnv = process.env.NODE_ENV;
     process.env.NODE_ENV = "test";
 
     // Ensure update checks don't short-circuit in test mode.
-    hadVitest = Object.prototype.hasOwnProperty.call(process.env, "VITEST");
-    prevVitest = process.env.VITEST;
     delete process.env.VITEST;
 
     // Perf: load mocked modules once (after timers/env are set up).
@@ -91,21 +82,7 @@ describe("update-startup", () => {
 
   afterEach(async () => {
     vi.useRealTimers();
-    if (hadStateDir) {
-      process.env.OPENCLAW_STATE_DIR = prevStateDir;
-    } else {
-      delete process.env.OPENCLAW_STATE_DIR;
-    }
-    if (hadNodeEnv) {
-      process.env.NODE_ENV = prevNodeEnv;
-    } else {
-      delete process.env.NODE_ENV;
-    }
-    if (hadVitest) {
-      process.env.VITEST = prevVitest;
-    } else {
-      delete process.env.VITEST;
-    }
+    envSnapshot.restore();
     resetUpdateAvailableStateForTest();
   });
 
diff --git a/src/test-utils/env.test.ts b/src/test-utils/env.test.ts
index 07c01c09758..a978c4bc45c 100644
--- a/src/test-utils/env.test.ts
+++ b/src/test-utils/env.test.ts
@@ -40,6 +40,22 @@ describe("env test utils", () => {
     expect(process.env[key]).toBe(prev);
   });
 
+  it("withEnv can delete a key only inside callback", () => {
+    const key = "OPENCLAW_ENV_TEST_SYNC_DELETE";
+    const prev = process.env[key];
+    process.env[key] = "outer";
+
+    const seen = withEnv({ [key]: undefined }, () => process.env[key]);
+
+    expect(seen).toBeUndefined();
+    expect(process.env[key]).toBe("outer");
+    if (prev === undefined) {
+      delete process.env[key];
+    } else {
+      process.env[key] = prev;
+    }
+  });
+
   it("withEnvAsync restores values when callback throws", async () => {
     const key = "OPENCLAW_ENV_TEST_ASYNC";
     const prev = process.env[key];
@@ -63,4 +79,20 @@ describe("env test utils", () => {
     expect(seen).toBe("inside");
     expect(process.env[key]).toBe(prev);
   });
+
+  it("withEnvAsync can delete a key only inside callback", async () => {
+    const key = "OPENCLAW_ENV_TEST_ASYNC_DELETE";
+    const prev = process.env[key];
+    process.env[key] = "outer";
+
+    const seen = await withEnvAsync({ [key]: undefined }, async () => process.env[key]);
+
+    expect(seen).toBeUndefined();
+    expect(process.env[key]).toBe("outer");
+    if (prev === undefined) {
+      delete process.env[key];
+    } else {
+      process.env[key] = prev;
+    }
+  });
 });