feat: implement i18n

frontend/src/app/workspace/chats/[thread_id]/page.tsx

@@ -23,6 +23,7 @@ import { ThreadContext } from "@/components/workspace/messages/context";
 import { ThreadTitle } from "@/components/workspace/thread-title";
 import { Tooltip } from "@/components/workspace/tooltip";
 import { Welcome } from "@/components/workspace/welcome";
+import { useI18n } from "@/core/i18n/hooks";
 import { useLocalSettings } from "@/core/settings";
 import { type AgentThread } from "@/core/threads";
 import { useSubmitThread, useThreadStream } from "@/core/threads/hooks";
@@ -31,6 +32,7 @@ import { uuid } from "@/core/utils/uuid";
 import { cn } from "@/lib/utils";
 
 export default function ChatPage() {
+  const { t } = useI18n();
   const router = useRouter();
   const [settings, setSettings] = useLocalSettings();
   const { setOpen: setSidebarOpen } = useSidebar();
@@ -41,7 +43,6 @@ export default function ChatPage() {
     setArtifacts,
     selectedArtifact,
   } = useArtifacts();
-
   const { thread_id: threadIdFromPath } = useParams<{ thread_id: string }>();
   const isNewThread = useMemo(
     () => threadIdFromPath === "new",
@@ -117,7 +118,7 @@ export default function ChatPage() {
                       }}
                     >
                       <FilesIcon />
-                      Artifacts
+                      {t.common.artifacts}
                     </Button>
                   </Tooltip>
                 )}

frontend/src/app/workspace/chats/page.tsx

@@ -10,11 +10,13 @@ import {
   WorkspaceContainer,
   WorkspaceHeader,
 } from "@/components/workspace/workspace-container";
+import { useI18n } from "@/core/i18n/hooks";
 import { useThreads } from "@/core/threads/hooks";
 import { pathOfThread, titleOfThread } from "@/core/threads/utils";
 import { formatTimeAgo } from "@/core/utils/datetime";
 
 export default function ChatsPage() {
+  const { t } = useI18n();
   const { data: threads } = useThreads();
   const [search, setSearch] = useState("");
   const filteredThreads = useMemo(() => {
@@ -31,7 +33,7 @@ export default function ChatsPage() {
             <Input
               type="search"
               className="h-12 w-full max-w-(--container-width-md) text-xl"
-              placeholder="Search chats"
+              placeholder={t.chats.searchChats}
               autoFocus
               value={search}
               onChange={(e) => setSearch(e.target.value)}

frontend/src/components/workspace/artifacts/artifact-file-detail.tsx

@@ -27,6 +27,7 @@ import { Textarea } from "@/components/ui/textarea";
 import { ToggleGroup, ToggleGroupItem } from "@/components/ui/toggle-group";
 import { useArtifactContent } from "@/core/artifacts/hooks";
 import { urlOfArtifact } from "@/core/artifacts/utils";
+import { useI18n } from "@/core/i18n/hooks";
 import { checkCodeFile, getFileName } from "@/core/utils/files";
 import { cn } from "@/lib/utils";
 
@@ -41,6 +42,7 @@ export function ArtifactFileDetail({
   filepath: string;
   threadId: string;
 }) {
+  const { t } = useI18n();
   const { artifacts, setOpen, select } = useArtifacts();
   const isWriteFile = useMemo(() => {
     return filepathFromProps.startsWith("write-file:");
@@ -124,26 +126,26 @@ export function ArtifactFileDetail({
               <a href={urlOfArtifact({ filepath, threadId })} target="_blank">
                 <ArtifactAction
                   icon={SquareArrowOutUpRightIcon}
-                  label="Open in new window"
-                  tooltip="Open in new window"
+                  label={t.common.openInNewWindow}
+                  tooltip={t.common.openInNewWindow}
                 />
               </a>
             )}
             {isCodeFile && (
               <ArtifactAction
                 icon={CopyIcon}
-                label="Copy"
+                label={t.clipboard.copyToClipboard}
                 disabled={!content}
                 onClick={async () => {
                   try {
                     await navigator.clipboard.writeText(content ?? "");
-                    toast.success("Copied to clipboard");
+                    toast.success(t.clipboard.copiedToClipboard);
                   } catch (error) {
                     toast.error("Failed to copy to clipboard");
                     console.error(error);
                   }
                 }}
-                tooltip="Copy content to clipboard"
+                tooltip={t.clipboard.copyToClipboard}
               />
             )}
             {!isWriteFile && (
@@ -153,17 +155,16 @@ export function ArtifactFileDetail({
               >
                 <ArtifactAction
                   icon={DownloadIcon}
-                  label="Download"
-                  onClick={() => console.log("Download")}
-                  tooltip="Download file"
+                  label={t.common.download}
+                  tooltip={t.common.download}
                 />
               </a>
             )}
             <ArtifactAction
               icon={XIcon}
-              label="Close"
+              label={t.common.close}
               onClick={() => setOpen(false)}
-              tooltip="Close"
+              tooltip={t.common.close}
             />
           </ArtifactActions>
         </div>

frontend/src/components/workspace/artifacts/artifact-file-list.tsx

@@ -10,6 +10,7 @@ import {
   CardTitle,
 } from "@/components/ui/card";
 import { urlOfArtifact } from "@/core/artifacts/utils";
+import { useI18n } from "@/core/i18n/hooks";
 import { getFileExtensionDisplayName, getFileName } from "@/core/utils/files";
 import { cn } from "@/lib/utils";
 
@@ -24,6 +25,7 @@ export function ArtifactFileList({
   files: string[];
   threadId: string;
 }) {
+  const { t } = useI18n();
   const { select: selectArtifact, setOpen } = useArtifacts();
   const handleClick = useCallback(
     (filepath: string) => {
@@ -57,7 +59,7 @@ export function ArtifactFileList({
               >
                 <Button variant="ghost">
                   <DownloadIcon className="size-4" />
-                  Download
+                  {t.common.download}
                 </Button>
               </a>
             </CardAction>

frontend/src/components/workspace/copy-button.tsx

@@ -2,6 +2,7 @@ import { CheckIcon, CopyIcon } from "lucide-react";
 import { useCallback, useState, type ComponentProps } from "react";
 
 import { Button } from "@/components/ui/button";
+import { useI18n } from "@/core/i18n/hooks";
 
 import { Tooltip } from "./tooltip";
 
@@ -11,6 +12,7 @@ export function CopyButton({
 }: ComponentProps<typeof Button> & {
   clipboardData: string;
 }) {
+  const { t } = useI18n();
   const [copied, setCopied] = useState(false);
   const handleCopy = useCallback(() => {
     void navigator.clipboard.writeText(clipboardData);
@@ -18,7 +20,7 @@ export function CopyButton({
     setTimeout(() => setCopied(false), 2000);
   }, [clipboardData]);
   return (
-    <Tooltip content="Copy to clipboard">
+    <Tooltip content={t.clipboard.copyToClipboard}>
       <Button
         size="icon-sm"
         type="button"

frontend/src/components/workspace/input-box.tsx

@@ -1,3 +1,5 @@
+"use client";
+
 import type { ChatStatus } from "ai";
 import { CheckIcon, LightbulbIcon, LightbulbOffIcon } from "lucide-react";
 import { useCallback, useMemo, useState, type ComponentProps } from "react";
@@ -11,6 +13,7 @@ import {
   PromptInputTextarea,
   type PromptInputMessage,
 } from "@/components/ai-elements/prompt-input";
+import { useI18n } from "@/core/i18n/hooks";
 import { useModels } from "@/core/models/hooks";
 import type { AgentThreadContext } from "@/core/threads";
 import { cn } from "@/lib/utils";
@@ -40,11 +43,11 @@ export function InputBox({
   assistantId?: string | null;
   status?: ChatStatus;
   context: Omit<AgentThreadContext, "thread_id">;
-  showWelcome?: boolean;
   onContextChange?: (context: Omit<AgentThreadContext, "thread_id">) => void;
   onSubmit?: (message: PromptInputMessage) => void;
   onStop?: () => void;
 }) {
+  const { t } = useI18n();
   const [modelDialogOpen, setModelDialogOpen] = useState(false);
   const { models } = useModels();
   const selectedModel = useMemo(
@@ -97,7 +100,7 @@ export function InputBox({
       <PromptInputBody>
         <PromptInputTextarea
           className={cn("size-full")}
-          placeholder="How can I assist you today?"
+          placeholder={t.inputBox.placeholder}
           autoFocus={autoFocus}
         />
       </PromptInputBody>
@@ -107,13 +110,17 @@ export function InputBox({
             content={
               context.thinking_enabled ? (
                 <div className="tex-sm flex flex-col gap-1">
-                  <div>Thinking is enabled</div>
-                  <div className="opacity-50">Click to disable thinking</div>
+                  <div>{t.inputBox.thinkingEnabled}</div>
+                  <div className="opacity-50">
+                    {t.inputBox.clickToDisableThinking}
+                  </div>
                 </div>
               ) : (
                 <div className="tex-sm flex flex-col gap-1">
-                  <div>Thinking is disabled</div>
-                  <div className="opacity-50">Click to enable thinking</div>
+                  <div>{t.inputBox.thinkingDisabled}</div>
+                  <div className="opacity-50">
+                    {t.inputBox.clickToEnableThinking}
+                  </div>
                 </div>
               )
             }
@@ -142,7 +149,7 @@ export function InputBox({
               </PromptInputButton>
             </ModelSelectorTrigger>
             <ModelSelectorContent>
-              <ModelSelectorInput placeholder="Search models..." />
+              <ModelSelectorInput placeholder={t.inputBox.searchModels} />
               <ModelSelectorList>
                 {models.map((m) => (
                   <ModelSelectorItem

frontend/src/components/workspace/messages/message-group.tsx

@@ -21,8 +21,10 @@ import {
   ChainOfThoughtSearchResults,
   ChainOfThoughtStep,
 } from "@/components/ai-elements/chain-of-thought";
+import { CodeBlock } from "@/components/ai-elements/code-block";
 import { MessageResponse } from "@/components/ai-elements/message";
 import { Button } from "@/components/ui/button";
+import { useI18n } from "@/core/i18n/hooks";
 import {
   extractReasoningContentFromMessage,
   findToolCallResult,
@@ -33,7 +35,6 @@ import { cn } from "@/lib/utils";
 
 import { useArtifacts } from "../artifacts";
 import { FlipDisplay } from "../flip-display";
-import { CodeBlock } from "@/components/ai-elements/code-block";
 
 export function MessageGroup({
   className,
@@ -44,6 +45,7 @@ export function MessageGroup({
   messages: Message[];
   isLoading?: boolean;
 }) {
+  const { t } = useI18n();
   const [showAbove, setShowAbove] = useState(false);
   const [showLastThinking, setShowLastThinking] = useState(false);
   const steps = useMemo(() => convertToSteps(messages), [messages]);
@@ -84,8 +86,8 @@ export function MessageGroup({
             label={
               <span className="opacity-60">
                 {showAbove
-                  ? "Less steps"
-                  : `${aboveLastToolCallSteps.length} more step${aboveLastToolCallSteps.length === 1 ? "" : "s"}`}
+                  ? t.toolCalls.lessSteps
+                  : t.toolCalls.moreSteps(aboveLastToolCallSteps.length)}
               </span>
             }
             icon={
@@ -134,7 +136,7 @@ export function MessageGroup({
             <div className="flex w-full items-center justify-between">
               <ChainOfThoughtStep
                 className="font-normal"
-                label="Thinking"
+                label={t.common.thinking}
                 icon={LightbulbIcon}
               ></ChainOfThoughtStep>
               <div>
@@ -178,16 +180,12 @@ function ToolCall({
   args: Record<string, unknown>;
   result?: string | Record<string, unknown>;
 }) {
+  const { t } = useI18n();
   const { select, setOpen } = useArtifacts();
   if (name === "web_search") {
-    let label: React.ReactNode = "Search for related information";
+    let label: React.ReactNode = t.toolCalls.searchForRelatedInfo;
     if (typeof args.query === "string") {
-      label = (
-        <div>
-          Search on the web for{" "}
-          <span className="font-bold">&quot;{args.query}&quot;</span>
-        </div>
-      );
+      label = t.toolCalls.searchOnWebFor(args.query);
     }
     return (
       <ChainOfThoughtStep key={id} label={label} icon={SearchIcon}>
@@ -217,7 +215,7 @@ function ToolCall({
       <ChainOfThoughtStep
         key={id}
         className="cursor-pointer"
-        label="View web page"
+        label={t.toolCalls.viewWebPage}
         icon={GlobeIcon}
         onClick={() => {
           window.open(url, "_blank");
@@ -236,7 +234,7 @@ function ToolCall({
     let description: string | undefined = (args as { description: string })
       ?.description;
     if (!description) {
-      description = "List folder";
+      description = t.toolCalls.listFolder;
     }
     const path: string | undefined = (args as { path: string })?.path;
     return (
@@ -250,7 +248,7 @@ function ToolCall({
     let description: string | undefined = (args as { description: string })
       ?.description;
     if (!description) {
-      description = "Read file";
+      description = t.toolCalls.readFile;
     }
     const path: string | undefined = (args as { path: string })?.path;
     return (
@@ -264,7 +262,7 @@ function ToolCall({
     let description: string | undefined = (args as { description: string })
       ?.description;
     if (!description) {
-      description = "Write file";
+      description = t.toolCalls.writeFile;
     }
     const path: string | undefined = (args as { path: string })?.path;
     return (
@@ -291,7 +289,7 @@ function ToolCall({
     const description: string | undefined = (args as { description: string })
       ?.description;
     if (!description) {
-      return "Execute command";
+      return t.toolCalls.executeCommand;
     }
     const command: string | undefined = (args as { command: string })?.command;
     return (
@@ -312,7 +310,11 @@ function ToolCall({
     );
   } else if (name === "present_files") {
     return (
-      <ChainOfThoughtStep key={id} label="Present files" icon={FileTextIcon}>
+      <ChainOfThoughtStep
+        key={id}
+        label={t.toolCalls.presentFiles}
+        icon={FileTextIcon}
+      >
         <ChainOfThoughtSearchResult>
           {Array.isArray((args as { filepaths: string[] }).filepaths) &&
             (args as { filepaths: string[] }).filepaths.map(
@@ -330,7 +332,7 @@ function ToolCall({
     return (
       <ChainOfThoughtStep
         key={id}
-        label="Need your help"
+        label={t.toolCalls.needYourHelp}
         icon={MessageCircleQuestionMarkIcon}
       ></ChainOfThoughtStep>
     );
@@ -340,13 +342,7 @@ function ToolCall({
     return (
       <ChainOfThoughtStep
         key={id}
-        label={
-          description ?? (
-            <div>
-              Use &quot;<span className="font-bold">{name}</span>&quot; tool
-            </div>
-          )
-        }
+        label={description ?? t.toolCalls.useTool(name)}
         icon={WrenchIcon}
       ></ChainOfThoughtStep>
     );

frontend/src/components/workspace/recent-chat-list.tsx

@@ -20,10 +20,12 @@ import {
   SidebarMenuButton,
   SidebarMenuItem,
 } from "@/components/ui/sidebar";
+import { useI18n } from "@/core/i18n/hooks";
 import { useDeleteThread, useThreads } from "@/core/threads/hooks";
 import { pathOfThread, titleOfThread } from "@/core/threads/utils";
 
 export function RecentChatList() {
+  const { t } = useI18n();
   const router = useRouter();
   const pathname = usePathname();
   const { thread_id: threadIdFromPath } = useParams<{ thread_id: string }>();
@@ -52,7 +54,7 @@ export function RecentChatList() {
   }
   return (
     <SidebarGroup>
-      <SidebarGroupLabel>Recent chats</SidebarGroupLabel>
+      <SidebarGroupLabel>{t.sidebar.recentChats}</SidebarGroupLabel>
       <SidebarGroupContent className="group-data-[collapsible=icon]:pointer-events-none group-data-[collapsible=icon]:-mt-8 group-data-[collapsible=icon]:opacity-0">
         <SidebarMenu>
           <div className="flex w-full flex-col gap-1">
@@ -78,7 +80,7 @@ export function RecentChatList() {
                             className="bg-background/50 hover:bg-background"
                           >
                             <MoreHorizontal />
-                            <span className="sr-only">More</span>
+                            <span className="sr-only">{t.common.more}</span>
                           </SidebarMenuAction>
                         </DropdownMenuTrigger>
                         <DropdownMenuContent
@@ -90,7 +92,7 @@ export function RecentChatList() {
                             onSelect={() => handleDelete(thread.thread_id)}
                           >
                             <Trash2 className="text-muted-foreground" />
-                            <span>Delete</span>
+                            <span>{t.common.delete}</span>
                           </DropdownMenuItem>
                         </DropdownMenuContent>
                       </DropdownMenu>

frontend/src/components/workspace/welcome.tsx

@@ -1,6 +1,10 @@
+"use client";
+
+import { useI18n } from "@/core/i18n/hooks";
 import { cn } from "@/lib/utils";
 
 export function Welcome({ className }: { className?: string }) {
+  const { t } = useI18n();
   return (
     <div
       className={cn(
@@ -8,17 +12,13 @@ export function Welcome({ className }: { className?: string }) {
         className,
       )}
     >
-      <div className="text-2xl font-bold">👋 Hello, again!</div>
+      <div className="text-2xl font-bold">{t.welcome.greeting}</div>
       <div className="text-muted-foreground text-sm">
-        <p>
-          Welcome to 🦌 DeerFlow, an open source super agent. With built-in and
-          custom
-        </p>
-        <p>
-          skills, DeerFlow helps you search on the web, analyze data, and
-          generate
-        </p>{" "}
-        <p>artifacts like slides, web pages and do almost anything.</p>
+        {t.welcome.description.includes("\n") ? (
+          <pre className="whitespace-pre">{t.welcome.description}</pre>
+        ) : (
+          <p>{t.welcome.description}</p>
+        )}
       </div>
     </div>
   );

frontend/src/components/workspace/workspace-container.tsx

@@ -12,6 +12,7 @@ import {
   BreadcrumbPage,
   BreadcrumbSeparator,
 } from "@/components/ui/breadcrumb";
+import { useI18n } from "@/core/i18n/hooks";
 import { cn } from "@/lib/utils";
 
 import { GithubIcon } from "./github-icon";
@@ -34,6 +35,7 @@ export function WorkspaceHeader({
   children,
   ...props
 }: React.ComponentProps<"header">) {
+  const { t } = useI18n();
   const pathname = usePathname();
   const segments = useMemo(() => {
     const parts = pathname?.split("/") || [];
@@ -56,7 +58,7 @@ export function WorkspaceHeader({
               <BreadcrumbItem className="hidden md:block">
                 <BreadcrumbLink asChild>
                   <Link href={`/${segments[0]}`}>
-                    {nameOfSegment(segments[0])}
+                    {nameOfSegment(segments[0], t)}
                   </Link>
                 </BreadcrumbLink>
               </BreadcrumbItem>
@@ -68,12 +70,12 @@ export function WorkspaceHeader({
                   {segments.length >= 2 ? (
                     <BreadcrumbLink asChild>
                       <Link href={`/${segments[0]}/${segments[1]}`}>
-                        {nameOfSegment(segments[1])}
+                        {nameOfSegment(segments[1], t)}
                       </Link>
                     </BreadcrumbLink>
                   ) : (
                     <BreadcrumbPage>
-                      {nameOfSegment(segments[1])}
+                      {nameOfSegment(segments[1], t)}
                     </BreadcrumbPage>
                   )}
                 </BreadcrumbItem>
@@ -89,7 +91,7 @@ export function WorkspaceHeader({
         </Breadcrumb>
       </div>
       <div className="pr-4">
-        <Tooltip content="DeerFlow on Github">
+        <Tooltip content={t.workspace.githubTooltip}>
           <a
             href="https://github.com/bytedance/deer-flow"
             target="_blank"
@@ -122,7 +124,12 @@ export function WorkspaceBody({
   );
 }
 
-function nameOfSegment(segment: string | undefined) {
-  if (!segment) return "Home";
+function nameOfSegment(
+  segment: string | undefined,
+  t: ReturnType<typeof useI18n>["t"],
+) {
+  if (!segment) return t.common.home;
+  if (segment === "workspace") return t.breadcrumb.workspace;
+  if (segment === "chats") return t.breadcrumb.chats;
   return segment[0]?.toUpperCase() + segment.slice(1);
 }

frontend/src/components/workspace/workspace-header.tsx

@@ -11,9 +11,11 @@ import {
   SidebarTrigger,
   useSidebar,
 } from "@/components/ui/sidebar";
+import { useI18n } from "@/core/i18n/hooks";
 import { cn } from "@/lib/utils";
 
 export function WorkspaceHeader({ className }: { className?: string }) {
+  const { t } = useI18n();
   const { state } = useSidebar();
   const pathname = usePathname();
   return (
@@ -48,7 +50,7 @@ export function WorkspaceHeader({ className }: { className?: string }) {
           >
             <Link className="text-muted-foreground" href="/workspace/chats/new">
               <MessageSquarePlus size={16} />
-              <span>New chat</span>
+              <span>{t.sidebar.newChat}</span>
             </Link>
           </SidebarMenuButton>
         </SidebarMenuItem>

frontend/src/components/workspace/workspace-nav-menu.tsx

@@ -10,8 +10,10 @@ import {
   SidebarMenuButton,
   SidebarMenuItem,
 } from "@/components/ui/sidebar";
+import { useI18n } from "@/core/i18n/hooks";
 
 export function WorkspaceNavMenu() {
+  const { t } = useI18n();
   const pathname = usePathname();
   return (
     <SidebarGroup className="pt-1">
@@ -20,7 +22,7 @@ export function WorkspaceNavMenu() {
           <SidebarMenuButton isActive={pathname === "/workspace/chats"} asChild>
             <Link className="text-muted-foreground" href="/workspace/chats">
               <MessagesSquare />
-              <span>Chats</span>
+              <span>{t.sidebar.chats}</span>
             </Link>
           </SidebarMenuButton>
         </SidebarMenuItem>

frontend/src/components/workspace/workspace-sidebar.tsx

@@ -1,10 +1,18 @@
+import { SettingsIcon } from "lucide-react";
+
 import {
   Sidebar,
   SidebarHeader,
   SidebarContent,
   SidebarFooter,
   SidebarRail,
+  SidebarMenu,
+  SidebarMenuItem,
+  SidebarMenuButton,
+  SidebarGroup,
+  SidebarGroupContent,
 } from "@/components/ui/sidebar";
+import { useI18n } from "@/core/i18n/hooks";
 
 import { RecentChatList } from "./recent-chat-list";
 import { WorkspaceHeader } from "./workspace-header";
@@ -13,6 +21,7 @@ import { WorkspaceNavMenu } from "./workspace-nav-menu";
 export function WorkspaceSidebar({
   ...props
 }: React.ComponentProps<typeof Sidebar>) {
+  const { t } = useI18n();
   return (
     <Sidebar variant="sidebar" collapsible="icon" {...props}>
       <SidebarHeader className="py-0">
@@ -22,7 +31,22 @@ export function WorkspaceSidebar({
         <WorkspaceNavMenu />
         <RecentChatList />
       </SidebarContent>
-      <SidebarFooter></SidebarFooter>
+      <SidebarFooter>
+        <SidebarGroup className="px-0">
+          <SidebarGroupContent>
+            <SidebarMenu>
+              <SidebarMenuItem>
+                <SidebarMenuButton asChild>
+                  <div className="text-muted-foreground cursor-pointer">
+                    <SettingsIcon size={16} />
+                    <span>{t.common.settings}</span>
+                  </div>
+                </SidebarMenuButton>
+              </SidebarMenuItem>
+            </SidebarMenu>
+          </SidebarGroupContent>
+        </SidebarGroup>
+      </SidebarFooter>
       <SidebarRail />
     </Sidebar>
   );

frontend/src/core/i18n/hooks.ts

@@ -0,0 +1,57 @@
+"use client";
+
+import { useEffect, useState } from "react";
+
+import { enUS } from "./locales/en-US";
+import { zhCN } from "./locales/zh-CN";
+
+import { detectLocale, type Locale, type Translations } from "./index";
+
+const translations: Record<Locale, Translations> = {
+  "en-US": enUS,
+  "zh-CN": zhCN,
+};
+
+export function useI18n() {
+  const [locale, setLocale] = useState<Locale>(() => {
+    if (typeof window === "undefined") {
+      return "en-US";
+    }
+
+    // Try to get from localStorage first
+    const saved = localStorage.getItem("locale") as Locale | null;
+    if (saved && (saved === "en-US" || saved === "zh-CN")) {
+      return saved;
+    }
+
+    // Otherwise detect from browser
+    return detectLocale();
+  });
+
+  const t = translations[locale];
+
+  const changeLocale = (newLocale: Locale) => {
+    setLocale(newLocale);
+    if (typeof window !== "undefined") {
+      localStorage.setItem("locale", newLocale);
+    }
+  };
+
+  // Initialize locale on mount
+  useEffect(() => {
+    if (typeof window !== "undefined") {
+      const saved = localStorage.getItem("locale") as Locale | null;
+      if (!saved) {
+        const detected = detectLocale();
+        setLocale(detected);
+        localStorage.setItem("locale", detected);
+      }
+    }
+  }, []);
+
+  return {
+    locale,
+    t,
+    changeLocale,
+  };
+}

frontend/src/core/i18n/index.ts

@@ -0,0 +1,23 @@
+export { enUS } from "./locales/en-US";
+export { zhCN } from "./locales/zh-CN";
+export type { Translations } from "./locales/types";
+
+export type Locale = "en-US" | "zh-CN";
+
+// Helper function to detect browser locale
+export function detectLocale(): Locale {
+  // if (typeof window === "undefined") {
+  //   return "en-US";
+  // }
+
+  // const browserLang =
+  //   navigator.language ||
+  //   (navigator as unknown as { userLanguage: string }).userLanguage;
+
+  // // Check if browser language is Chinese (zh, zh-CN, zh-TW, etc.)
+  // if (browserLang.toLowerCase().startsWith("zh")) {
+  //   return "zh-CN";
+  // }
+
+  return "en-US";
+}

frontend/src/core/i18n/locales/en-US.ts

@@ -0,0 +1,86 @@
+import type { Translations } from "./types";
+
+export const enUS: Translations = {
+  // Common
+  common: {
+    home: "Home",
+    settings: "Settings",
+    delete: "Delete",
+    openInNewWindow: "Open in new window",
+    close: "Close",
+    more: "More",
+    search: "Search",
+    download: "Download",
+    thinking: "Thinking",
+    artifacts: "Artifacts",
+  },
+
+  // Welcome
+  welcome: {
+    greeting: "👋 Hello, again!",
+    description:
+      "Welcome to 🦌 DeerFlow, an open source super agent. With built-in and custom skills, DeerFlow helps you search on the web, analyze data, and generate artifacts like slides, web pages and do almost anything.",
+  },
+
+  // Clipboard
+  clipboard: {
+    copyToClipboard: "Copy to clipboard",
+    copiedToClipboard: "Copied to clipboard",
+    failedToCopyToClipboard: "Failed to copy to clipboard",
+  },
+
+  // Input Box
+  inputBox: {
+    placeholder: "How can I assist you today?",
+    thinkingEnabled: "Thinking is enabled",
+    thinkingDisabled: "Thinking is disabled",
+    clickToDisableThinking: "Click to disable thinking",
+    clickToEnableThinking: "Click to enable thinking",
+    searchModels: "Search models...",
+  },
+
+  // Sidebar
+  sidebar: {
+    newChat: "New chat",
+    chats: "Chats",
+    recentChats: "Recent chats",
+  },
+
+  // Breadcrumb
+  breadcrumb: {
+    workspace: "Workspace",
+    chats: "Chats",
+  },
+
+  // Workspace
+  workspace: {
+    githubTooltip: "DeerFlow on Github",
+  },
+
+  // Conversation
+  conversation: {
+    noMessages: "No messages yet",
+    startConversation: "Start a conversation to see messages here",
+  },
+
+  // Chats
+  chats: {
+    searchChats: "Search chats",
+  },
+
+  // Tool calls
+  toolCalls: {
+    moreSteps: (count: number) => `${count} more step${count === 1 ? "" : "s"}`,
+    lessSteps: "Less steps",
+    executeCommand: "Execute command",
+    presentFiles: "Present files",
+    needYourHelp: "Need your help",
+    useTool: (toolName: string) => `Use "${toolName}" tool`,
+    searchForRelatedInfo: "Search for related information",
+    searchOnWebFor: (query: string) => `Search on the web for "${query}"`,
+    viewWebPage: "View web page",
+    listFolder: "List folder",
+    readFile: "Read file",
+    writeFile: "Write file",
+  },
+};

frontend/src/core/i18n/locales/index.ts

@@ -0,0 +1,3 @@
+export { enUS } from "./en-US";
+export { zhCN } from "./zh-CN";
+export type { Translations } from "./types";

frontend/src/core/i18n/locales/types.ts

@@ -0,0 +1,83 @@
+export interface Translations {
+  // Common
+  common: {
+    home: string;
+    settings: string;
+    delete: string;
+    openInNewWindow: string;
+    close: string;
+    more: string;
+    search: string;
+    download: string;
+    thinking: string;
+    artifacts: string;
+  };
+
+  // Welcome
+  welcome: {
+    greeting: string;
+    description: string;
+  };
+
+  // Clipboard
+  clipboard: {
+    copyToClipboard: string;
+    copiedToClipboard: string;
+    failedToCopyToClipboard: string;
+  };
+
+  // Input Box
+  inputBox: {
+    placeholder: string;
+    thinkingEnabled: string;
+    thinkingDisabled: string;
+    clickToDisableThinking: string;
+    clickToEnableThinking: string;
+    searchModels: string;
+  };
+
+  // Sidebar
+  sidebar: {
+    recentChats: string;
+    newChat: string;
+    chats: string;
+  };
+
+  // Breadcrumb
+  breadcrumb: {
+    workspace: string;
+    chats: string;
+  };
+
+  // Workspace
+  workspace: {
+    githubTooltip: string;
+  };
+
+  // Conversation
+  conversation: {
+    noMessages: string;
+    startConversation: string;
+  };
+
+  // Chats
+  chats: {
+    searchChats: string;
+  };
+
+  // Tool calls
+  toolCalls: {
+    moreSteps: (count: number) => string;
+    lessSteps: string;
+    executeCommand: string;
+    presentFiles: string;
+    needYourHelp: string;
+    useTool: (toolName: string) => string;
+    searchForRelatedInfo: string;
+    searchOnWebFor: (query: string) => string;
+    viewWebPage: string;
+    listFolder: string;
+    readFile: string;
+    writeFile: string;
+  };
+}

frontend/src/core/i18n/locales/zh-CN.ts

@@ -0,0 +1,86 @@
+import type { Translations } from "./types";
+
+export const zhCN: Translations = {
+  // Common
+  common: {
+    home: "首页",
+    settings: "设置",
+    delete: "删除",
+    openInNewWindow: "在新窗口打开",
+    close: "关闭",
+    more: "更多",
+    search: "搜索",
+    download: "下载",
+    thinking: "思考",
+    artifacts: "文件",
+  },
+
+  // Welcome
+  welcome: {
+    greeting: "👋 你好，欢迎回来！",
+    description:
+      "欢迎使用 🦌 DeerFlow，一个完全开源的超级智能体。通过内置和\n自定义的 Skills，DeerFlow 可以帮你搜索网络、分析数据，\n还能为你生成幻灯片、网页等作品，几乎可以做任何事情。",
+  },
+
+  // Clipboard
+  clipboard: {
+    copyToClipboard: "复制到剪贴板",
+    copiedToClipboard: "已复制到剪贴板",
+    failedToCopyToClipboard: "复制到剪贴板失败",
+  },
+
+  // Input Box
+  inputBox: {
+    placeholder: "今天我能为你做些什么？",
+    thinkingEnabled: "思考功能已启用",
+    thinkingDisabled: "思考功能已禁用",
+    clickToDisableThinking: "点击禁用思考功能",
+    clickToEnableThinking: "点击启用思考功能",
+    searchModels: "搜索模型...",
+  },
+
+  // Sidebar
+  sidebar: {
+    newChat: "新对话",
+    chats: "对话",
+    recentChats: "最近的聊天",
+  },
+
+  // Breadcrumb
+  breadcrumb: {
+    workspace: "工作区",
+    chats: "对话",
+  },
+
+  // Workspace
+  workspace: {
+    githubTooltip: "DeerFlow 在 Github",
+  },
+
+  // Conversation
+  conversation: {
+    noMessages: "还没有消息",
+    startConversation: "开始新的对话以查看消息",
+  },
+
+  // Chats
+  chats: {
+    searchChats: "搜索对话",
+  },
+
+  // Tool calls
+  toolCalls: {
+    moreSteps: (count: number) => `查看其他 ${count} 个步骤`,
+    lessSteps: "隐藏步骤",
+    executeCommand: "执行命令",
+    presentFiles: "展示文件",
+    needYourHelp: "需要你的协助",
+    useTool: (toolName: string) => `使用 “${toolName}” 工具`,
+    searchForRelatedInfo: "搜索相关信息",
+    searchOnWebFor: (query: string) => `在网络上搜索 “${query}”`,
+    viewWebPage: "查看网页",
+    listFolder: "列出文件夹",
+    readFile: "读取文件",
+    writeFile: "写入文件",
+  },
+};