From d8860595201d346f5be8237d0982400a788aac01 Mon Sep 17 00:00:00 2001
From: mushuiyu886 <yang.haoyu@xydigit.com>
Date: Sun, 12 Jul 2026 08:03:58 +0800
Subject: [PATCH] fix(line): preserve Unicode boundaries in recipient errors
 (#104109)

---
 extensions/line/src/send.test.ts | 18 ++++++++++++++++++
 extensions/line/src/send.ts      |  2 +-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/extensions/line/src/send.test.ts b/extensions/line/src/send.test.ts
index 0038979f3cc1..fff00336b80a 100644
--- a/extensions/line/src/send.test.ts
+++ b/extensions/line/src/send.test.ts
@@ -384,6 +384,24 @@ describe("LINE send helpers", () => {
     expect(pushMessageMock).not.toHaveBeenCalled();
   });
 
+  it("preserves UTF-16 boundaries in invalid recipient diagnostics", async () => {
+    await expect(
+      sendModule.pushMessagesLine(`aab😀${"x".repeat(40)}`, [{ type: "text", text: "hello" }], {
+        cfg: LINE_TEST_CFG,
+      }),
+    ).rejects.toThrow(
+      "Recipient is not a valid LINE id (case-sensitive; expected leading capital C/U/R): aab…",
+    );
+    await expect(
+      sendModule.pushMessagesLine(`aa😀${"y".repeat(40)}`, [{ type: "text", text: "hello" }], {
+        cfg: LINE_TEST_CFG,
+      }),
+    ).rejects.toThrow(
+      "Recipient is not a valid LINE id (case-sensitive; expected leading capital C/U/R): aa😀…",
+    );
+    expect(pushMessageMock).not.toHaveBeenCalled();
+  });
+
   it("accepts case-exact LINE recipients with the leading capital preserved", async () => {
     await sendModule.pushMessagesLine(
       "Cabcdef0123456789abcdef0123456789",
diff --git a/extensions/line/src/send.ts b/extensions/line/src/send.ts
index b63060ddce5e..7b223abfbe34 100644
--- a/extensions/line/src/send.ts
+++ b/extensions/line/src/send.ts
@@ -79,7 +79,7 @@ function normalizeTarget(to: string): string {
   // fixtures (e.g. "U123") are left alone. openclaw/openclaw#81628
   if (normalized.length >= 33 && !/^[CUR]/.test(normalized)) {
     throw new Error(
-      `Recipient is not a valid LINE id (case-sensitive; expected leading capital C/U/R): ${normalized.slice(0, 4)}…`,
+      `Recipient is not a valid LINE id (case-sensitive; expected leading capital C/U/R): ${truncateUtf16Safe(normalized, 4)}…`,
     );
   }