diff --git a/scripts/lib/cross-os-release-checks/network-smokes.ts b/scripts/lib/cross-os-release-checks/network-smokes.ts
index 0f8acf2cbe0a..c37a9d23c463 100644
--- a/scripts/lib/cross-os-release-checks/network-smokes.ts
+++ b/scripts/lib/cross-os-release-checks/network-smokes.ts
@@ -1,5 +1,6 @@
 import { randomUUID } from "node:crypto";
 import { join } from "node:path";
+import { truncateUtf16Safe } from "../../../packages/normalization-core/src/utf16-slice.ts";
 import type { GatewayHandle, LaneState } from "./config.ts";
 import {
   CROSS_OS_DASHBOARD_FETCH_TIMEOUT_MS,
@@ -157,7 +158,7 @@ export async function readBoundedCrossOsResponseText(
 
       text += decoder.decode(value, { stream: true });
       if (text.length > maxChars) {
-        text = text.slice(0, maxChars);
+        text = truncateUtf16Safe(text, maxChars);
         truncated = true;
         break;
       }
diff --git a/scripts/lib/cross-os-release-checks/shared.ts b/scripts/lib/cross-os-release-checks/shared.ts
index 7caba1940b1d..fa345e0a67f5 100644
--- a/scripts/lib/cross-os-release-checks/shared.ts
+++ b/scripts/lib/cross-os-release-checks/shared.ts
@@ -1,5 +1,6 @@
 import { existsSync } from "node:fs";
 import { join } from "node:path";
+import { truncateUtf16Safe } from "../../../packages/normalization-core/src/utf16-slice.ts";
 
 export function resolveCommandPath(command: string) {
   const pathValue = process.env.PATH ?? "";
@@ -28,7 +29,7 @@ export function trimForSummary(value: string) {
   if (trimmed.length <= 600) {
     return trimmed;
   }
-  return `${trimmed.slice(0, 600)}...`;
+  return `${truncateUtf16Safe(trimmed, 600)}...`;
 }
 
 export function formatError(error: unknown) {
diff --git a/test/scripts/openclaw-cross-os-release-checks.test.ts b/test/scripts/openclaw-cross-os-release-checks.test.ts
index 53b3e9541d97..ae875e1dba14 100644
--- a/test/scripts/openclaw-cross-os-release-checks.test.ts
+++ b/test/scripts/openclaw-cross-os-release-checks.test.ts
@@ -88,6 +88,7 @@ import {
   resolveRunnerMatrix,
   resolveStaticFileContentType,
   startStaticFileServer,
+  trimForSummary,
   shouldExerciseManagedGatewayLifecycleAfterInstall,
   shouldRunPackagedUpgradeStatusProbe,
   shouldRunWindowsInstalledBrowserOverrideImportSmoke,
@@ -210,6 +211,41 @@ describe("scripts/openclaw-cross-os-release-checks", () => {
     expect(CROSS_OS_FETCH_BODY_MAX_CHARS).toBeGreaterThan(1024);
   });
 
+  it.each([
+    {
+      caseName: "drops a split surrogate pair",
+      responseBody: `abc\u{1f600}tail`,
+      expectedText: "abc\n[truncated]",
+    },
+    {
+      caseName: "preserves a complete surrogate pair",
+      responseBody: `ab\u{1f600}tail`,
+      expectedText: `ab\u{1f600}\n[truncated]`,
+    },
+  ])(
+    "keeps cross-OS response truncation UTF-16 safe: $caseName",
+    async ({ responseBody, expectedText }) => {
+      const response = new Response(responseBody);
+
+      await expect(readBoundedCrossOsResponseText(response, 4)).resolves.toBe(expectedText);
+    },
+  );
+
+  it.each([
+    {
+      caseName: "drops a split surrogate pair",
+      input: `${"x".repeat(599)}\u{1f600}tail`,
+      expected: `${"x".repeat(599)}...`,
+    },
+    {
+      caseName: "preserves a complete surrogate pair",
+      input: `${"x".repeat(598)}\u{1f600}tail`,
+      expected: `${"x".repeat(598)}\u{1f600}...`,
+    },
+  ])("keeps cross-OS summaries UTF-16 safe: $caseName", ({ input, expected }) => {
+    expect(trimForSummary(input)).toBe(expected);
+  });
+
   it("keeps cross-OS fetch timeouts active while reading response bodies", async () => {
     let canceled = false;
     const abortController = new AbortController();