diff --git a/scripts/e2e/lib/bundled-plugin-install-uninstall/runtime-smoke.mjs b/scripts/e2e/lib/bundled-plugin-install-uninstall/runtime-smoke.mjs
index 7f4f7bac6ed..4c93b4c3ab5 100644
--- a/scripts/e2e/lib/bundled-plugin-install-uninstall/runtime-smoke.mjs
+++ b/scripts/e2e/lib/bundled-plugin-install-uninstall/runtime-smoke.mjs
@@ -68,7 +68,7 @@ function readPositiveInt(raw, fallback, name) {
     throw new Error(`invalid ${name}: ${text}`);
   }
   const parsed = Number(text);
-  if (!Number.isInteger(parsed) || parsed <= 0) {
+  if (!Number.isSafeInteger(parsed) || parsed <= 0) {
     throw new Error(`invalid ${name}: ${text}`);
   }
   return parsed;
diff --git a/test/scripts/bundled-plugin-install-uninstall-probe.test.ts b/test/scripts/bundled-plugin-install-uninstall-probe.test.ts
index 12c36643b7a..f6bb5c54c46 100644
--- a/test/scripts/bundled-plugin-install-uninstall-probe.test.ts
+++ b/test/scripts/bundled-plugin-install-uninstall-probe.test.ts
@@ -266,6 +266,14 @@ describe("bundled plugin install/uninstall probe", () => {
     expect(result.stderr).toContain("invalid bundled plugin runtime index: 1e3");
   });
 
+  it("rejects unsafe bundled plugin runtime limit env values", async () => {
+    await expect(
+      importRuntimeSmokeWithEnv({
+        OPENCLAW_BUNDLED_PLUGIN_RUNTIME_READY_MS: String(Number.MAX_SAFE_INTEGER + 1),
+      }),
+    ).rejects.toThrow("invalid OPENCLAW_BUNDLED_PLUGIN_RUNTIME_READY_MS: 9007199254740992");
+  });
+
   it("rejects bundled plugin runtime ports outside the TCP range", async () => {
     const runtimeSmoke = await import(pathToFileURL(runtimeSmokePath).href);
     const env = {