diff --git a/src/features/launcher/AccountGrid.tsx b/src/features/launcher/AccountGrid.tsx
index dc77813..2764b00 100644
--- a/src/features/launcher/AccountGrid.tsx
+++ b/src/features/launcher/AccountGrid.tsx
@@ -19,6 +19,7 @@ export function AccountGrid({ selectedAccountId, onSelectAccount }: AccountGridP
   const { data: accounts, isLoading } = useGameAccounts();
   const refreshAccounts = useRefreshAccounts();
   const [contextMenu, setContextMenu] = useState<ContextState | null>(null);
+  const [copiedId, setCopiedId] = useState<string | null>(null);
 
   const handleContextMenu = useCallback((e: React.MouseEvent, accountId: string) => {
     e.preventDefault();
@@ -27,6 +28,13 @@ export function AccountGrid({ selectedAccountId, onSelectAccount }: AccountGridP
 
   const closeContextMenu = useCallback(() => setContextMenu(null), []);
 
+  function handleCopyAccount(e: React.MouseEvent, accountId: string) {
+    e.stopPropagation();
+    navigator.clipboard.writeText(accountId);
+    setCopiedId(accountId);
+    setTimeout(() => setCopiedId(null), 1500);
+  }
+
   return (
     <div className="flex flex-1 flex-col gap-2 overflow-hidden">
       <div className="flex items-center justify-between">
@@ -46,17 +54,59 @@ export function AccountGrid({ selectedAccountId, onSelectAccount }: AccountGridP
             {accounts.map((account) => {
               const isSelected = selectedAccountId === account.id;
               const initial = account.displayName.charAt(0).toUpperCase();
+              const isCopied = copiedId === account.id;
               return (
                 <button
                   key={account.id}
                   onClick={() => onSelectAccount(account)}
                   onContextMenu={(e) => handleContextMenu(e, account.id)}
-                  className={`group flex flex-col items-center gap-1.5 rounded-xl border p-3 text-center backdrop-blur-sm transition-colors duration-150 ${
+                  className={`group relative flex flex-col items-center gap-1.5 rounded-xl border p-3 text-center backdrop-blur-sm transition-colors duration-150 ${
                     isSelected
                       ? "border-accent bg-[rgba(232,162,58,0.05)] shadow-[0_0_20px_rgba(232,162,58,0.15)]"
                       : "border-border bg-[var(--surface)] hover:border-[var(--border)] hover:bg-[var(--surface-hover)]"
                   }`}
                 >
+                  {/* Copy button — top-right, visible on hover */}
+                  <span
+                    role="button"
+                    tabIndex={-1}
+                    onClick={(e) => handleCopyAccount(e, account.id)}
+                    title={t("launcher.context.copy_account")}
+                    className={`absolute top-1.5 right-1.5 rounded p-0.5 transition-all ${
+                      isCopied
+                        ? "text-green-400 opacity-100"
+                        : "text-text-faint opacity-0 group-hover:opacity-100 hover:text-accent"
+                    }`}
+                  >
+                    {isCopied ? (
+                      <svg
+                        width="12"
+                        height="12"
+                        viewBox="0 0 24 24"
+                        fill="none"
+                        stroke="currentColor"
+                        strokeWidth="2.5"
+                        strokeLinecap="round"
+                        strokeLinejoin="round"
+                      >
+                        <polyline points="20 6 9 17 4 12" />
+                      </svg>
+                    ) : (
+                      <svg
+                        width="12"
+                        height="12"
+                        viewBox="0 0 24 24"
+                        fill="none"
+                        stroke="currentColor"
+                        strokeWidth="2"
+                        strokeLinecap="round"
+                        strokeLinejoin="round"
+                      >
+                        <rect x="9" y="9" width="13" height="13" rx="2" />
+                        <path d="M5 15H4a2 2 0 0 1-2-2V4a2 2 0 0 1 2-2h9a2 2 0 0 1 2 2v1" />
+                      </svg>
+                    )}
+                  </span>
                   <div
                     className={`flex h-[38px] w-[38px] items-center justify-center rounded-full border-2 text-sm font-bold transition-colors duration-150 ${
                       isSelected
diff --git a/src/features/launcher/OtpPanel.tsx b/src/features/launcher/OtpPanel.tsx
index b960dd1..5344044 100644
--- a/src/features/launcher/OtpPanel.tsx
+++ b/src/features/launcher/OtpPanel.tsx
@@ -2,6 +2,7 @@ import { useState } from "react";
 import { useTranslation } from "../../lib/i18n";
 import { useGameCredentials } from "../../lib/hooks/use-accounts";
 import { useAuthStore } from "../../lib/stores/auth-store";
+import { useErrorToastStore } from "../../lib/stores/error-toast-store";
 import { commands } from "../../lib/tauri";
 import type { GameCredentialsDto } from "../../lib/types";
 
@@ -11,12 +12,39 @@ interface OtpPanelProps {
 }
 
 export function OtpPanel({ selectedAccountId, onOtpFetched }: OtpPanelProps) {
-  const { t } = useTranslation();
   const credentialsMutation = useGameCredentials();
   const [credentials, setCredentials] = useState<GameCredentialsDto | null>(null);
   const [copied, setCopied] = useState(false);
   const [autoInput, setAutoInput] = useState(true);
   const [pasting, setPasting] = useState(false);
+  const { t } = useTranslation();
+  const addToast = useErrorToastStore((s) => s.addToast);
+
+  function handleOtpError(error: Error) {
+    const msg = error.message || t("launcher.otp_error");
+    const isSessionGone =
+      msg.includes("Not authenticated") ||
+      msg.includes("expired") ||
+      msg.includes("閒置過久") ||
+      msg.includes("重新登入") ||
+      msg.includes("Invalid credentials");
+
+    if (isSessionGone) {
+      // Session is dead — remove it and redirect to login
+      const sessionId = useAuthStore.getState().activeSessionId;
+      if (sessionId) {
+        commands.logout(sessionId).catch(() => {});
+        useAuthStore.getState().removeSession(sessionId);
+      }
+      addToast({
+        message: t("errors.AUTH_SESSION_EXPIRED"),
+        category: "authentication",
+        critical: true,
+      });
+    } else {
+      addToast({ message: msg, category: "authentication", critical: false });
+    }
+  }
 
   async function handleGetOtp() {
     if (!selectedAccountId) return;
@@ -42,6 +70,7 @@ export function OtpPanel({ selectedAccountId, onOtpFetched }: OtpPanelProps) {
               setTimeout(() => setCopied(false), 2000);
             }
           },
+          onError: handleOtpError,
         });
       } catch {
         // Error — fall back to regular OTP
@@ -51,6 +80,7 @@ export function OtpPanel({ selectedAccountId, onOtpFetched }: OtpPanelProps) {
             onOtpFetched?.(selectedAccountId, data.otp);
             setCopied(false);
           },
+          onError: handleOtpError,
         });
       } finally {
         setPasting(false);
@@ -63,6 +93,7 @@ export function OtpPanel({ selectedAccountId, onOtpFetched }: OtpPanelProps) {
           onOtpFetched?.(selectedAccountId, data.otp);
           setCopied(false);
         },
+        onError: handleOtpError,
       });
     }
   }
diff --git a/src/locales/en-US.json b/src/locales/en-US.json
index 23137b3..012f8f9 100644
--- a/src/locales/en-US.json
+++ b/src/locales/en-US.json
@@ -173,6 +173,7 @@
   "launcher.otp": "One-Time Password",
   "launcher.otp_placeholder": "Select an account to get OTP",
   "launcher.get_otp": "Get OTP",
+  "launcher.otp_error": "Failed to retrieve OTP",
   "launcher.fetching_otp": "Fetching...",
   "launcher.auto_input": "Auto Input",
   "launcher.game_info": "MapleStory",
diff --git a/src/locales/zh-CN.json b/src/locales/zh-CN.json
index 0853f86..974247f 100644
--- a/src/locales/zh-CN.json
+++ b/src/locales/zh-CN.json
@@ -173,6 +173,7 @@
   "launcher.otp": "一次性密码",
   "launcher.otp_placeholder": "选择账号以获取 OTP",
   "launcher.get_otp": "获取 OTP",
+  "launcher.otp_error": "获取密码失败",
   "launcher.fetching_otp": "获取中...",
   "launcher.auto_input": "自动输入",
   "launcher.game_info": "MapleStory",
diff --git a/src/locales/zh-TW.json b/src/locales/zh-TW.json
index 24b0c6b..e29de75 100644
--- a/src/locales/zh-TW.json
+++ b/src/locales/zh-TW.json
@@ -179,6 +179,7 @@
   "launcher.otp": "一次性密碼",
   "launcher.otp_placeholder": "選擇帳號以取得 OTP",
   "launcher.get_otp": "取得 OTP",
+  "launcher.otp_error": "取得密碼失敗",
   "launcher.fetching_otp": "取得中...",
   "launcher.auto_input": "自動輸入",
   "launcher.game_info": "MapleStory",