feat: add error handling

web/src/app/_components/toaster.tsx

@@ -0,0 +1,33 @@
+// Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+// SPDX-License-Identifier: MIT
+
+"use client";
+
+import { useTheme } from "next-themes";
+import { Toaster as Sonner } from "sonner";
+
+type ToasterProps = React.ComponentProps<typeof Sonner>;
+
+const Toaster = ({ ...props }: ToasterProps) => {
+  const { resolvedTheme = "dark" } = useTheme();
+  return (
+    <Sonner
+      theme={resolvedTheme as ToasterProps["theme"]}
+      className="toaster group"
+      toastOptions={{
+        classNames: {
+          toast:
+            "group toast group-[.toaster]:bg-background group-[.toaster]:text-foreground group-[.toaster]:border-border group-[.toaster]:shadow-lg",
+          description: "group-[.toast]:text-muted-foreground",
+          actionButton:
+            "group-[.toast]:bg-primary group-[.toast]:text-primary-foreground",
+          cancelButton:
+            "group-[.toast]:bg-muted group-[.toast]:text-muted-foreground",
+        },
+      }}
+      {...props}
+    />
+  );
+};
+
+export { Toaster };

web/src/app/_components/tooltip.tsx

@@ -6,6 +6,7 @@ import {
   TooltipContent,
   TooltipTrigger,
 } from "~/components/ui/tooltip";
+import { cn } from "~/lib/utils";
 
 export function Tooltip({
   className,
@@ -25,7 +26,11 @@ export function Tooltip({
   return (
     <ShadcnTooltip delayDuration={750} open={open}>
       <TooltipTrigger asChild>{children}</TooltipTrigger>
-      <TooltipContent side={side} sideOffset={sideOffset} className={className}>
+      <TooltipContent
+        side={side}
+        sideOffset={sideOffset}
+        className={cn(className)}
+      >
         {title}
       </TooltipContent>
     </ShadcnTooltip>

web/src/app/layout.tsx

@@ -9,6 +9,8 @@ import { Geist } from "next/font/google";
 import { ThemeProviderWrapper } from "~/app/_components/theme-provider-wrapper";
 import { TooltipProvider } from "~/components/ui/tooltip";
 
+import { Toaster } from "./_components/toaster";
+
 export const metadata: Metadata = {
   title: "🦌 DeerFlow",
   description:
@@ -30,6 +32,7 @@ export default function RootLayout({
         <ThemeProviderWrapper>
           <TooltipProvider>{children}</TooltipProvider>
         </ThemeProviderWrapper>
+        <Toaster />
       </body>
     </html>
   );

web/src/core/store/store.ts

@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: MIT
 
 import { nanoid } from "nanoid";
+import { toast } from "sonner";
 import { create } from "zustand";
 
 import { chatStream, generatePodcast } from "../api";
@@ -136,6 +137,7 @@ export async function sendMessage(
       }
     }
   } catch {
+    toast("An error occurred while generating the response. Please try again.");
     // Update message status.
     // TODO: const isAborted = (error as Error).name === "AbortError";
     if (messageId != null) {