feat(history): Implement conversation history management with artifact restoration and Markdown rendering.

.gitignore

@@ -20,3 +20,4 @@ langchain-docs/
 # VS Code / IDEs
 .vscode/
 .idea/
+CODE_REVIEW.md

backend/src/ea_chatbot/api/routers/history.py

@@ -59,7 +59,8 @@ async def get_conversation_messages(
             "id": str(m.id),
             "role": m.role,
             "content": m.content,
-            "created_at": m.created_at
+            "created_at": m.created_at,
+            "plot_ids": [str(p.id) for p in m.plots]
         } for m in messages
     ]
 

backend/src/ea_chatbot/api/schemas.py

@@ -37,7 +37,7 @@ class MessageResponse(BaseModel):
     role: str
     content: str
     created_at: datetime
-    # Plots are fetched separately via artifact endpoints
+    plot_ids: List[str] = []
 
 class ConversationUpdate(BaseModel):
     name: Optional[str] = None

backend/src/ea_chatbot/app.py

@@ -328,7 +328,8 @@ def main():
             "code_output": None,
             "error": None,
             "plots": [],
-            "dfs": {}
+            "dfs": {},
+            "iterations": 0
         }
 
         # Placeholder for graph output

frontend/package.json

@@ -13,6 +13,7 @@
   "dependencies": {
     "@hookform/resolvers": "^5.2.2",
     "@tailwindcss/vite": "^4.1.18",
+    "@types/react-syntax-highlighter": "^15.5.13",
     "axios": "^1.13.5",
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
@@ -21,7 +22,10 @@
     "react": "^19.2.0",
     "react-dom": "^19.2.0",
     "react-hook-form": "^7.71.1",
+    "react-markdown": "^10.1.0",
     "react-router-dom": "^7.13.0",
+    "react-syntax-highlighter": "^16.1.0",
+    "remark-gfm": "^4.0.1",
     "tailwind-merge": "^3.4.0",
     "tailwindcss": "^4.1.18",
     "zod": "^4.3.6"

frontend/src/App.tsx

@@ -6,7 +6,8 @@ import { RegisterForm } from "./components/auth/RegisterForm"
 import { AuthCallback } from "./components/auth/AuthCallback"
 import { ChatInterface } from "./components/chat/ChatInterface"
 import { AuthService, type UserResponse } from "./services/auth"
-import { ChatService } from "./services/chat"
+import { ChatService, type MessageResponse } from "./services/chat"
+import { type Conversation } from "./components/layout/HistorySidebar"
 import { registerUnauthorizedCallback } from "./services/api"
 
 function App() {
@@ -15,12 +16,17 @@ function App() {
   const [authMode, setAuthMode] = useState<"login" | "register">("login")
   const [isLoading, setIsLoading] = useState(true)
   const [selectedThreadId, setSelectedThreadId] = useState<string | null>(null)
+  const [conversations, setConversations] = useState<Conversation[]>([])
+  const [threadMessages, setThreadMessages] = useState<Record<string, MessageResponse[]>>({})
 
   useEffect(() => {
     // Register callback to handle session expiration from anywhere in the app
     registerUnauthorizedCallback(() => {
       setIsAuthenticated(false)
       setUser(null)
+      setConversations([])
+      setSelectedThreadId(null)
+      setThreadMessages({})
     })
 
     const initAuth = async () => {
@@ -28,8 +34,9 @@ function App() {
         const userData = await AuthService.getMe()
         setUser(userData)
         setIsAuthenticated(true)
+        // Load history after successful auth
+        loadHistory()
       } catch (err: unknown) {
-        // Not logged in or session expired - this is expected if no cookie
         console.log("No active session found", err)
         setIsAuthenticated(false)
       } finally {
@@ -40,11 +47,21 @@ function App() {
     initAuth()
   }, [])
 
+  const loadHistory = async () => {
+    try {
+      const history = await ChatService.listConversations()
+      setConversations(history)
+    } catch (err) {
+      console.error("Failed to load conversation history:", err)
+    }
+  }
+
   const handleAuthSuccess = async () => {
     try {
       const userData = await AuthService.getMe()
       setUser(userData)
       setIsAuthenticated(true)
+      loadHistory()
     } catch (err: unknown) {
       console.error("Failed to fetch user profile after login:", err)
     }
@@ -59,19 +76,65 @@ function App() {
       setIsAuthenticated(false)
       setUser(null)
       setSelectedThreadId(null)
+      setConversations([])
+      setThreadMessages({})
     }
   }
 
-  const handleCreateTempChat = async () => {
+  const handleSelectConversation = async (id: string) => {
+    setSelectedThreadId(id)
+    // Always fetch messages to avoid stale cache issues when switching back
+    // or if the session was updated from elsewhere
     try {
-      const conv = await ChatService.createConversation("Temporary Chat")
+      const msgs = await ChatService.getMessages(id)
-      setSelectedThreadId(conv.id)
+      setThreadMessages(prev => ({ ...prev, [id]: msgs }))
+    } catch (err) {
+      console.error("Failed to fetch messages:", err)
+    }
+  }
+
+  const handleCreateConversation = async () => {
+    try {
+      const newConv = await ChatService.createConversation()
+      setConversations(prev => [newConv, ...prev])
+      setSelectedThreadId(newConv.id)
+      setThreadMessages(prev => ({ ...prev, [newConv.id]: [] }))
     } catch (err) {
       console.error("Failed to create conversation:", err)
-      alert("Failed to start chat session. Please try again.")
     }
   }
 
+  const handleRenameConversation = async (id: string, name: string) => {
+    try {
+      const updated = await ChatService.renameConversation(id, name)
+      setConversations(prev => prev.map(c => c.id === id ? updated : c))
+    } catch (err) {
+      console.error("Failed to rename conversation:", err)
+    }
+  }
+
+  const handleDeleteConversation = async (id: string) => {
+    try {
+      await ChatService.deleteConversation(id)
+      setConversations(prev => prev.filter(c => c.id !== id))
+      // Also clear from cache
+      setThreadMessages(prev => {
+        const next = { ...prev }
+        delete next[id]
+        return next
+      })
+      if (selectedThreadId === id) {
+        setSelectedThreadId(null)
+      }
+    } catch (err) {
+      console.error("Failed to delete conversation:", err)
+    }
+  }
+
+  const handleMessagesFinal = (id: string, messages: MessageResponse[]) => {
+    setThreadMessages(prev => ({ ...prev, [id]: messages }))
+  }
+
   if (isLoading) {
     return (
       <div className="min-h-screen flex items-center justify-center bg-background">
@@ -101,7 +164,14 @@ function App() {
               )}
             </div>
           ) : (
-            <MainLayout>
+            <MainLayout
+              conversations={conversations}
+              selectedId={selectedThreadId}
+              onSelect={handleSelectConversation}
+              onCreate={handleCreateConversation}
+              onRename={handleRenameConversation}
+              onDelete={handleDeleteConversation}
+            >
               <div className="flex flex-col h-full gap-4">
                 <div className="flex justify-between items-center shrink-0">
                   <div>
@@ -119,7 +189,12 @@ function App() {
                 
                 <div className="flex-1 min-h-0">
                   {selectedThreadId ? (
-                    <ChatInterface threadId={selectedThreadId} />
+                    <ChatInterface 
+                      key={selectedThreadId} // Force remount on thread change
+                      threadId={selectedThreadId} 
+                      initialMessages={threadMessages[selectedThreadId] || []}
+                      onMessagesFinal={(msgs) => handleMessagesFinal(selectedThreadId, msgs)}
+                    />
                   ) : (
                     <div className="flex flex-col items-center justify-center h-full text-center space-y-4 bg-muted/30 rounded-xl border border-dashed p-12">
                       <div className="p-4 bg-background rounded-full shadow-sm">
@@ -144,10 +219,10 @@ function App() {
                           Create a new conversation in the sidebar to start asking questions.
                         </p>
                         <button 
-                          onClick={handleCreateTempChat}
+                          onClick={handleCreateConversation}
                           className="mt-4 px-4 py-2 bg-primary text-primary-foreground rounded-md text-sm font-medium hover:bg-primary/90"
                         >
-                          Start Temporary Chat
+                          Start New Chat
                         </button>
                       </div>
                     </div>

frontend/src/components/chat/ChatInterface.test.tsx

@@ -1,7 +1,7 @@
 import { render, screen, fireEvent, waitFor } from "@testing-library/react"
 import { describe, it, expect, vi, beforeEach } from "vitest"
 import { ChatInterface } from "./ChatInterface"
-import { ChatService, type StreamCallbacks } from "@/services/chat"
+import { ChatService, type StreamCallbacks, type MessageResponse } from "@/services/chat"
 
 vi.mock("@/services/chat", () => ({
   ChatService: {
@@ -42,7 +42,7 @@ describe("ChatInterface", () => {
 
   it("displays error message when stream fails", async () => {
     const mockedStreamChat = vi.mocked(ChatService.streamChat)
-    mockedStreamChat.mockImplementation((_msg: string, _id: string, _msgs: any[], callbacks: StreamCallbacks) => {
+    mockedStreamChat.mockImplementation((_msg: string, _id: string, _msgs: MessageResponse[], callbacks: StreamCallbacks) => {
       if (callbacks.onError) {
         callbacks.onError("Connection failed")
       }

frontend/src/components/chat/ChatInterface.tsx

@@ -8,11 +8,16 @@ import { Alert, AlertDescription, AlertTitle } from "@/components/ui/alert"
 interface ChatInterfaceProps {
   threadId: string
   initialMessages?: MessageResponse[]
+  onMessagesFinal?: (messages: MessageResponse[]) => void
 }
 
 const EMPTY_MESSAGES: MessageResponse[] = []
 
-export function ChatInterface({ threadId, initialMessages = EMPTY_MESSAGES }: ChatInterfaceProps) {
+export function ChatInterface({ 
+  threadId, 
+  initialMessages = EMPTY_MESSAGES,
+  onMessagesFinal
+}: ChatInterfaceProps) {
   const [messages, setMessages] = React.useState<MessageResponse[]>(initialMessages)
   const [isStreaming, setIsStreaming] = React.useState(false)
   const [error, setError] = React.useState<string | null>(null)
@@ -42,6 +47,9 @@ export function ChatInterface({ threadId, initialMessages = EMPTY_MESSAGES }: Ch
           onMessageUpdate: (updatedMessages) => {
             setMessages(updatedMessages)
           },
+          onMessagesFinal: (finalMessages) => {
+            if (onMessagesFinal) onMessagesFinal(finalMessages)
+          },
           onDone: () => {
             setIsStreaming(false)
           },

frontend/src/components/chat/MarkdownContent.tsx

@@ -0,0 +1,78 @@
+import ReactMarkdown, { type Components } from "react-markdown"
+import remarkGfm from "remark-gfm"
+import { Prism as SyntaxHighlighter } from "react-syntax-highlighter"
+import { oneDark } from "react-syntax-highlighter/dist/esm/styles/prism"
+
+interface MarkdownContentProps {
+  content: string
+}
+
+export function MarkdownContent({ content }: MarkdownContentProps) {
+  const components: Components = {
+    code({ children, className }) {
+      const match = /language-(\w+)/.exec(className || "")
+      if (match) {
+        return (
+          <SyntaxHighlighter
+            style={oneDark}
+            language={match[1]}
+            PreTag="div"
+            customStyle={{
+              margin: "1rem 0",
+              borderRadius: "0.5rem",
+              fontSize: "0.875rem",
+            }}
+          >
+            {String(children).replace(/\n$/, "")}
+          </SyntaxHighlighter>
+        )
+      }
+      return <code className={className}>{children}</code>
+    },
+    table({ children }) {
+      return (
+        <div className="my-4 w-full overflow-x-auto rounded-lg border">
+          <table className="w-full text-sm">{children}</table>
+        </div>
+      )
+    },
+    thead({ children }) {
+      return <thead className="bg-muted/50 border-b">{children}</thead>
+    },
+    th({ children }) {
+      return <th className="px-4 py-2 text-left font-semibold">{children}</th>
+    },
+    td({ children }) {
+      return <td className="border-t px-4 py-2">{children}</td>
+    },
+    p({ children }) {
+      return <p className="mb-2 last:mb-0">{children}</p>
+    },
+    ul({ children }) {
+      return <ul className="mb-4 list-disc pl-6 last:mb-0">{children}</ul>
+    },
+    ol({ children }) {
+      return <ol className="mb-4 list-decimal pl-6 last:mb-0">{children}</ol>
+    },
+    li({ children }) {
+      return <li className="mb-1">{children}</li>
+    },
+    h1({ children }) {
+      return <h1 className="mb-4 text-2xl font-bold">{children}</h1>
+    },
+    h2({ children }) {
+      return <h2 className="mb-3 text-xl font-bold">{children}</h2>
+    },
+    h3({ children }) {
+      return <h3 className="mb-2 text-lg font-bold">{children}</h3>
+    },
+  }
+
+  return (
+    <div className="text-sm leading-relaxed">
+      <ReactMarkdown remarkPlugins={[remarkGfm]} components={components}>
+        {content}
+      </ReactMarkdown>
+    </div>
+  )
+}

frontend/src/components/chat/MessageBubble.tsx

@@ -1,5 +1,6 @@
 import { cn } from "@/lib/utils"
 import { type MessageResponse } from "@/services/chat"
+import { MarkdownContent } from "./MarkdownContent"
 
 interface MessageBubbleProps {
   message: MessageResponse
@@ -43,8 +44,11 @@ export function MessageBubble({ message }: MessageBubbleProps) {
           </div>
         )}
 
-        <div className="whitespace-pre-wrap break-words text-sm">
+        <div className="break-words text-sm">
-          {message.content || (isAssistant && !message.plots?.length ? (
+          {isAssistant ? (
+            message.content ? (
+              <MarkdownContent content={message.content} />
+            ) : !message.plots?.length && !message.plot_ids?.length ? (
               <div className="flex items-center gap-1 py-1">
                 <div className="flex gap-1">
                   <div className="h-1.5 w-1.5 rounded-full bg-current animate-bounce [animation-delay:-0.3s]" />
@@ -52,14 +56,17 @@ export function MessageBubble({ message }: MessageBubbleProps) {
                   <div className="h-1.5 w-1.5 rounded-full bg-current animate-bounce" />
                 </div>
               </div>
-          ) : "")}
+            ) : null
+          ) : (
+            <div className="whitespace-pre-wrap">{message.content}</div>
+          )}
         </div>
         
-        {message.plots && message.plots.length > 0 && (
+        {(message.plots || message.plot_ids) && ((message.plots?.length || 0) > 0 || (message.plot_ids?.length || 0) > 0) && (
           <div className="mt-4 grid grid-cols-1 gap-2">
-            {message.plots.map((plot, index) => (
+            {message.plots?.map((plot, index) => (
               <img
-                key={index}
+                key={`stream-${index}`}
                 src={`data:image/png;base64,${plot}`}
                 alt="Analysis Plot"
                 className="rounded-md border bg-white w-full h-auto cursor-pointer hover:opacity-90 transition-opacity"
@@ -68,6 +75,17 @@ export function MessageBubble({ message }: MessageBubbleProps) {
                 }}
               />
             ))}
+            {message.plot_ids?.map((plotId, index) => (
+              <img
+                key={`history-${index}`}
+                src={`${import.meta.env.VITE_API_URL || ""}/api/v1/artifacts/plots/${plotId}`}
+                alt="Historical Analysis Plot"
+                className="rounded-md border bg-white w-full h-auto cursor-pointer hover:opacity-90 transition-opacity"
+                onClick={() => {
+                  // TODO: Open in modal (Phase 5)
+                }}
+              />
+            ))}
           </div>
         )}
       </div>

frontend/src/components/layout/HistorySidebar.tsx

@@ -0,0 +1,166 @@
+import * as React from "react"
+import { 
+  PlusIcon, 
+  MessageSquareIcon, 
+  MoreVerticalIcon, 
+  PencilIcon, 
+  TrashIcon,
+  CheckIcon,
+  XIcon 
+} from "lucide-react"
+import { 
+  Sidebar, 
+  SidebarContent, 
+  SidebarHeader, 
+  SidebarFooter,
+  SidebarGroup,
+  SidebarGroupLabel,
+  SidebarGroupContent,
+  SidebarMenu,
+  SidebarMenuItem,
+  SidebarMenuButton,
+  SidebarMenuAction
+} from "@/components/ui/sidebar"
+import { 
+  DropdownMenu, 
+  DropdownMenuContent, 
+  DropdownMenuItem, 
+  DropdownMenuTrigger 
+} from "@/components/ui/dropdown-menu"
+import { Button } from "@/components/ui/button"
+import { Input } from "@/components/ui/input"
+
+export interface Conversation {
+  id: string
+  name: string
+  created_at: string
+}
+
+interface HistorySidebarProps {
+  conversations: Conversation[]
+  selectedId: string | null
+  onSelect: (id: string) => void
+  onCreate: () => void
+  onRename: (id: string, newName: string) => void
+  onDelete: (id: string) => void
+}
+
+export function HistorySidebar({
+  conversations,
+  selectedId,
+  onSelect,
+  onCreate,
+  onRename,
+  onDelete,
+}: HistorySidebarProps) {
+  const [editingId, setEditingId] = React.useState<string | null>(null)
+  const [editValue, setEditValue] = React.useState("")
+
+  const handleStartRename = (conv: Conversation) => {
+    setEditingId(conv.id)
+    setEditValue(conv.name)
+  }
+
+  const handleConfirmRename = () => {
+    if (editingId && editValue.trim()) {
+      onRename(editingId, editValue.trim())
+    }
+    setEditingId(null)
+  }
+
+  const handleCancelRename = () => {
+    setEditingId(null)
+  }
+
+  const handleDelete = (id: string) => {
+    if (confirm("Are you sure you want to delete this conversation?")) {
+      onDelete(id)
+    }
+  }
+
+  return (
+    <Sidebar role="complementary">
+      <SidebarHeader className="border-b p-4">
+        <Button 
+          onClick={onCreate}
+          className="w-full justify-start gap-2" 
+          variant="outline"
+        >
+          <PlusIcon className="h-4 w-4" />
+          New Chat
+        </Button>
+      </SidebarHeader>
+      
+      <SidebarContent>
+        <SidebarGroup>
+          <SidebarGroupLabel>Recent Conversations</SidebarGroupLabel>
+          <SidebarGroupContent>
+            <SidebarMenu>
+              {conversations.map((conv) => (
+                <SidebarMenuItem key={conv.id}>
+                  {editingId === conv.id ? (
+                    <div className="flex items-center gap-1 p-1 w-full">
+                      <Input
+                        value={editValue}
+                        onChange={(e) => setEditValue(e.target.value)}
+                        className="h-7 text-sm"
+                        autoFocus
+                        onKeyDown={(e) => {
+                          if (e.key === "Enter") handleConfirmRename()
+                          if (e.key === "Escape") handleCancelRename()
+                        }}
+                      />
+                      <Button size="icon-xs" variant="ghost" onClick={handleConfirmRename}>
+                        <CheckIcon className="h-3 w-3" />
+                      </Button>
+                      <Button size="icon-xs" variant="ghost" onClick={handleCancelRename}>
+                        <XIcon className="h-3 w-3" />
+                      </Button>
+                    </div>
+                  ) : (
+                    <>
+                      <SidebarMenuButton
+                        isActive={selectedId === conv.id}
+                        onClick={() => onSelect(conv.id)}
+                        tooltip={conv.name}
+                      >
+                        <MessageSquareIcon className="h-4 w-4" />
+                        <span>{conv.name}</span>
+                      </SidebarMenuButton>
+                      
+                      <DropdownMenu>
+                        <DropdownMenuTrigger asChild>
+                          <SidebarMenuAction showOnHover>
+                            <MoreVerticalIcon className="h-4 w-4" />
+                            <span className="sr-only">Conversation actions</span>
+                          </SidebarMenuAction>
+                        </DropdownMenuTrigger>
+                        <DropdownMenuContent align="end" className="w-40">
+                          <DropdownMenuItem onClick={() => handleStartRename(conv)}>
+                            <PencilIcon className="mr-2 h-4 w-4" />
+                            Rename
+                          </DropdownMenuItem>
+                          <DropdownMenuItem 
+                            onClick={() => handleDelete(conv.id)}
+                            className="text-destructive focus:text-destructive"
+                          >
+                            <TrashIcon className="mr-2 h-4 w-4" />
+                            Delete
+                          </DropdownMenuItem>
+                        </DropdownMenuContent>
+                      </DropdownMenu>
+                    </>
+                  )}
+                </SidebarMenuItem>
+              ))}
+            </SidebarMenu>
+          </SidebarGroupContent>
+        </SidebarGroup>
+      </SidebarContent>
+      
+      <SidebarFooter className="border-t p-4">
+        <div className="text-xs text-muted-foreground">© 2026 Election Analytics</div>
+      </SidebarFooter>
+    </Sidebar>
+  )
+}

frontend/src/components/layout/MainLayout.test.tsx

@@ -1,11 +1,20 @@
 import { render, screen } from "@testing-library/react"
-import { describe, it, expect } from "vitest"
+import { describe, it, expect, vi } from "vitest"
 import { MainLayout } from "./MainLayout"
 
 describe("MainLayout", () => {
+  const mockProps = {
+    conversations: [],
+    selectedId: null,
+    onSelect: vi.fn(),
+    onCreate: vi.fn(),
+    onRename: vi.fn(),
+    onDelete: vi.fn(),
+  }
+
   it("renders children correctly", () => {
     render(
-      <MainLayout>
+      <MainLayout {...mockProps}>
         <div data-testid="test-child">Test Content</div>
       </MainLayout>
     )
@@ -14,13 +23,13 @@ describe("MainLayout", () => {
   })
 
   it("renders the sidebar", () => {
-    render(<MainLayout>Content</MainLayout>)
+    render(<MainLayout {...mockProps}>Content</MainLayout>)
     // Sidebar should have some identifying text or role
     expect(screen.getByRole("complementary")).toBeInTheDocument()
   })
 
   it("renders the header/navigation", () => {
-    render(<MainLayout>Content</MainLayout>)
+    render(<MainLayout {...mockProps}>Content</MainLayout>)
     expect(screen.getByRole("navigation")).toBeInTheDocument()
   })
 })

frontend/src/components/layout/MainLayout.tsx

@@ -1,25 +1,37 @@
 import * as React from "react"
-import { SidebarProvider, Sidebar, SidebarContent, SidebarHeader, SidebarFooter, SidebarInset, SidebarTrigger } from "@/components/ui/sidebar"
+import { SidebarProvider, SidebarInset, SidebarTrigger } from "@/components/ui/sidebar"
+import { HistorySidebar, type Conversation } from "./HistorySidebar"
 
 interface MainLayoutProps {
   children: React.ReactNode
+  conversations: Conversation[]
+  selectedId: string | null
+  onSelect: (id: string) => void
+  onCreate: () => void
+  onRename: (id: string, newName: string) => void
+  onDelete: (id: string) => void
 }
 
-export function MainLayout({ children }: MainLayoutProps) {
+export function MainLayout({ 
+  children,
+  conversations,
+  selectedId,
+  onSelect,
+  onCreate,
+  onRename,
+  onDelete
+}: MainLayoutProps) {
   return (
     <SidebarProvider>
       <div className="flex h-screen w-full overflow-hidden">
-        <Sidebar role="complementary">
+        <HistorySidebar 
-          <SidebarHeader>
+          conversations={conversations}
-            <div className="p-4 font-bold text-xl">EA Chatbot</div>
+          selectedId={selectedId}
-          </SidebarHeader>
+          onSelect={onSelect}
-          <SidebarContent>
+          onCreate={onCreate}
-            {/* Navigation links or conversation history will go here */}
+          onRename={onRename}
-          </SidebarContent>
+          onDelete={onDelete}
-          <SidebarFooter>
+        />
-            <div className="p-4 text-xs text-muted-foreground">© 2026 Election Analytics</div>
-          </SidebarFooter>
-        </Sidebar>
         <SidebarInset className="flex flex-col flex-1 h-full overflow-hidden">
           <header className="flex h-16 shrink-0 items-center gap-2 border-b px-4" role="navigation">
             <SidebarTrigger />

frontend/src/components/ui/dropdown-menu.tsx

@@ -0,0 +1,199 @@
+"use client"
+
+import * as React from "react"
+import { DropdownMenu as DropdownMenuPrimitive } from "radix-ui"
+import { CheckIcon, ChevronRightIcon, CircleIcon } from "lucide-react"
+
+import { cn } from "@/lib/utils"
+
+const DropdownMenu = DropdownMenuPrimitive.Root
+
+const DropdownMenuTrigger = DropdownMenuPrimitive.Trigger
+
+const DropdownMenuGroup = DropdownMenuPrimitive.Group
+
+const DropdownMenuPortal = DropdownMenuPrimitive.Portal
+
+const DropdownMenuSub = DropdownMenuPrimitive.Sub
+
+const DropdownMenuRadioGroup = DropdownMenuPrimitive.RadioGroup
+
+const DropdownMenuSubTrigger = React.forwardRef<
+  React.ElementRef<typeof DropdownMenuPrimitive.SubTrigger>,
+  React.ComponentPropsWithoutRef<typeof DropdownMenuPrimitive.SubTrigger> & {
+    inset?: boolean
+  }
+>(({ className, inset, children, ...props }, ref) => (
+  <DropdownMenuPrimitive.SubTrigger
+    ref={ref}
+    className={cn(
+      "focus:bg-accent data-[state=open]:bg-accent flex cursor-default items-center rounded-sm px-2 py-1.5 text-sm outline-hidden select-none",
+      inset && "pl-8",
+      className
+    )}
+    {...props}
+  >
+    {children}
+    <ChevronRightIcon className="ml-auto h-4 w-4" />
+  </DropdownMenuPrimitive.SubTrigger>
+))
+DropdownMenuSubTrigger.displayName = "DropdownMenuSubTrigger"
+
+const DropdownMenuSubContent = React.forwardRef<
+  React.ElementRef<typeof DropdownMenuPrimitive.SubContent>,
+  React.ComponentPropsWithoutRef<typeof DropdownMenuPrimitive.SubContent>
+>(({ className, ...props }, ref) => (
+  <DropdownMenuPrimitive.SubContent
+    ref={ref}
+    className={cn(
+      "bg-popover text-popover-foreground data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0 data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95 data-[side=bottom]:slide-in-from-top-2 data-[side=left]:slide-in-from-right-2 data-[side=right]:slide-in-from-left-2 data-[side=top]:slide-in-from-bottom-2 z-50 min-w-[8rem] overflow-hidden rounded-md border p-1 shadow-lg",
+      className
+    )}
+    {...props}
+  />
+))
+DropdownMenuSubContent.displayName = "DropdownMenuSubContent"
+
+const DropdownMenuContent = React.forwardRef<
+  React.ElementRef<typeof DropdownMenuPrimitive.Content>,
+  React.ComponentPropsWithoutRef<typeof DropdownMenuPrimitive.Content>
+>(({ className, sideOffset = 4, ...props }, ref) => (
+  <DropdownMenuPrimitive.Portal>
+    <DropdownMenuPrimitive.Content
+      ref={ref}
+      sideOffset={sideOffset}
+      className={cn(
+        "bg-popover text-popover-foreground data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0 data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95 data-[side=bottom]:slide-in-from-top-2 data-[side=left]:slide-in-from-right-2 data-[side=right]:slide-in-from-left-2 data-[side=top]:slide-in-from-bottom-2 z-50 min-w-[8rem] overflow-hidden rounded-md border p-1 shadow-md",
+        className
+      )}
+      {...props}
+    />
+  </DropdownMenuPrimitive.Portal>
+))
+DropdownMenuContent.displayName = "DropdownMenuContent"
+
+const DropdownMenuItem = React.forwardRef<
+  React.ElementRef<typeof DropdownMenuPrimitive.Item>,
+  React.ComponentPropsWithoutRef<typeof DropdownMenuPrimitive.Item> & {
+    inset?: boolean
+  }
+>(({ className, inset, children, ...props }, ref) => (
+  <DropdownMenuPrimitive.Item
+    ref={ref}
+    className={cn(
+      "focus:bg-accent focus:text-accent-foreground relative flex cursor-default items-center rounded-sm px-2 py-1.5 text-sm outline-hidden transition-colors data-[disabled]:pointer-events-none data-[disabled]:opacity-50 select-none",
+      inset && "pl-8",
+      className
+    )}
+    {...props}
+  >
+    {children}
+  </DropdownMenuPrimitive.Item>
+))
+DropdownMenuItem.displayName = "DropdownMenuItem"
+
+const DropdownMenuCheckboxItem = React.forwardRef<
+  React.ElementRef<typeof DropdownMenuPrimitive.CheckboxItem>,
+  React.ComponentPropsWithoutRef<typeof DropdownMenuPrimitive.CheckboxItem>
+>(({ className, children, checked, ...props }, ref) => (
+  <DropdownMenuPrimitive.CheckboxItem
+    ref={ref}
+    className={cn(
+      "focus:bg-accent focus:text-accent-foreground relative flex cursor-default items-center rounded-sm py-1.5 pr-2 pl-8 text-sm outline-hidden transition-colors data-[disabled]:pointer-events-none data-[disabled]:opacity-50 select-none",
+      className
+    )}
+    checked={checked}
+    {...props}
+  >
+    <span className="absolute left-2 flex h-3.5 w-3.5 items-center justify-center">
+      <DropdownMenuPrimitive.ItemIndicator>
+        <CheckIcon className="h-4 w-4" />
+      </DropdownMenuPrimitive.ItemIndicator>
+    </span>
+    {children}
+  </DropdownMenuPrimitive.CheckboxItem>
+))
+DropdownMenuCheckboxItem.displayName = "DropdownMenuCheckboxItem"
+
+const DropdownMenuRadioItem = React.forwardRef<
+  React.ElementRef<typeof DropdownMenuPrimitive.RadioItem>,
+  React.ComponentPropsWithoutRef<typeof DropdownMenuPrimitive.RadioItem>
+>(({ className, children, ...props }, ref) => (
+  <DropdownMenuPrimitive.RadioItem
+    ref={ref}
+    className={cn(
+      "focus:bg-accent focus:text-accent-foreground relative flex cursor-default items-center rounded-sm py-1.5 pr-2 pl-8 text-sm outline-hidden transition-colors data-[disabled]:pointer-events-none data-[disabled]:opacity-50 select-none",
+      className
+    )}
+    {...props}
+  >
+    <span className="absolute left-2 flex h-3.5 w-3.5 items-center justify-center">
+      <DropdownMenuPrimitive.ItemIndicator>
+        <CircleIcon className="h-2 w-2 fill-current" />
+      </DropdownMenuPrimitive.ItemIndicator>
+    </span>
+    {children}
+  </DropdownMenuPrimitive.RadioItem>
+))
+DropdownMenuRadioItem.displayName = "DropdownMenuRadioItem"
+
+const DropdownMenuLabel = React.forwardRef<
+  React.ElementRef<typeof DropdownMenuPrimitive.Label>,
+  React.ComponentPropsWithoutRef<typeof DropdownMenuPrimitive.Label> & {
+    inset?: boolean
+  }
+>(({ className, inset, ...props }, ref) => (
+  <DropdownMenuPrimitive.Label
+    ref={ref}
+    className={cn(
+      "px-2 py-1.5 text-sm font-semibold",
+      inset && "pl-8",
+      className
+    )}
+    {...props}
+  />
+))
+DropdownMenuLabel.displayName = "DropdownMenuLabel"
+
+const DropdownMenuSeparator = React.forwardRef<
+  React.ElementRef<typeof DropdownMenuPrimitive.Separator>,
+  React.ComponentPropsWithoutRef<typeof DropdownMenuPrimitive.Separator>
+>(({ className, ...props }, ref) => (
+  <DropdownMenuPrimitive.Separator
+    ref={ref}
+    className={cn("bg-muted -mx-1 my-1 h-px", className)}
+    {...props}
+  />
+))
+DropdownMenuSeparator.displayName = "DropdownMenuSeparator"
+
+const DropdownMenuShortcut = ({
+  className,
+  ...props
+}: React.HTMLAttributes<HTMLSpanElement>) => {
+  return (
+    <span
+      className={cn("ml-auto text-xs tracking-widest opacity-60", className)}
+      {...props}
+    />
+  )
+}
+DropdownMenuShortcut.displayName = "DropdownMenuShortcut"
+
+export {
+  DropdownMenu,
+  DropdownMenuTrigger,
+  DropdownMenuContent,
+  DropdownMenuItem,
+  DropdownMenuCheckboxItem,
+  DropdownMenuRadioItem,
+  DropdownMenuLabel,
+  DropdownMenuSeparator,
+  DropdownMenuShortcut,
+  DropdownMenuGroup,
+  DropdownMenuPortal,
+  DropdownMenuSub,
+  DropdownMenuSubContent,
+  DropdownMenuSubTrigger,
+  DropdownMenuRadioGroup,
+}

frontend/src/services/chat.test.ts

@@ -1,5 +1,5 @@
-import { describe, it, expect, vi } from "vitest"
+import { describe, it, expect } from "vitest"
-import { ChatService, type ChatEvent } from "./chat"
+import { ChatService, type ChatEvent, type MessageResponse } from "./chat"
 
 describe("ChatService SSE Parsing", () => {
   it("should correctly parse a text stream chunk", () => {
@@ -42,26 +42,26 @@ describe("ChatService SSE Parsing", () => {
 
 describe("ChatService Message State Management", () => {
   it("should append text chunks to the last message content", () => {
-    const messages = [{ id: "1", role: "assistant", content: "Initial", created_at: new Date().toISOString() }]
+    const messages: MessageResponse[] = [{ id: "1", role: "assistant", content: "Initial", created_at: new Date().toISOString() }]
     const event: ChatEvent = {
       type: "on_chat_model_stream",
       node: "summarizer",
       data: { chunk: { content: " text" } }
     }
     
-    const updatedMessages = ChatService.updateMessagesWithEvent(messages as any, event)
+    const updatedMessages = ChatService.updateMessagesWithEvent(messages, event)
     expect(updatedMessages[0].content).toBe("Initial text")
   })
 
   it("should add plots to the message state", () => {
-    const messages = [{ id: "1", role: "assistant", content: "Analysis", created_at: new Date().toISOString(), plots: [] }]
+    const messages: MessageResponse[] = [{ id: "1", role: "assistant", content: "Analysis", created_at: new Date().toISOString(), plots: [] }]
     const event: ChatEvent = {
       type: "on_chain_end",
       name: "executor",
       data: { encoded_plots: ["plot1"] }
     }
     
-    const updatedMessages = ChatService.updateMessagesWithEvent(messages as any, event)
+    const updatedMessages = ChatService.updateMessagesWithEvent(messages, event)
     expect(updatedMessages[0].plots).toEqual(["plot1"])
   })
 })

frontend/src/services/chat.ts

@@ -5,7 +5,8 @@ export interface MessageResponse {
   role: "user" | "assistant"
   content: string
   created_at: string
-  plots?: string[] // base64 encoded plots
+  plots?: string[] // base64 encoded plots (from stream)
+  plot_ids?: string[] // plot IDs (from history)
   steps?: string[] // reasoning steps
 }
 
@@ -13,11 +14,17 @@ export interface ChatEvent {
   type: string
   name?: string
   node?: string
-  data?: any
+  data?: {
+    chunk?: { content?: string }
+    output?: { messages?: { content: string }[] }
+    encoded_plots?: string[]
+    message?: string
+  }
 }
 
 export interface StreamCallbacks {
   onMessageUpdate: (messages: MessageResponse[]) => void
+  onMessagesFinal?: (messages: MessageResponse[]) => void
   onDone?: () => void
   onError?: (error: string) => void
 }
@@ -173,7 +180,7 @@ export const ChatService = {
     currentMessages: MessageResponse[],
     callbacks: StreamCallbacks
   ) {
-    const { onMessageUpdate, onDone, onError } = callbacks
+    const { onMessageUpdate, onMessagesFinal, onDone, onError } = callbacks
     
     // Add user message and a placeholder assistant message
     let activeMessages: MessageResponse[] = [
@@ -228,6 +235,7 @@ export const ChatService = {
 
         for (const event of events) {
           if (event.type === "done") {
+            if (onMessagesFinal) onMessagesFinal(activeMessages)
             if (onDone) onDone()
             continue
           }
@@ -256,6 +264,15 @@ export const ChatService = {
     return response.data
   },
 
+  async renameConversation(conversationId: string, name: string) {
+    const response = await api.patch(`/conversations/${conversationId}`, { name })
+    return response.data
+  },
+
+  async deleteConversation(conversationId: string) {
+    await api.delete(`/conversations/${conversationId}`)
+  },
+
   async getMessages(conversationId: string) {
     const response = await api.get(`/conversations/${conversationId}/messages`)
     return response.data

frontend/src/services/chat_history.test.ts

@@ -0,0 +1,55 @@
+import { describe, it, expect, vi, beforeEach } from "vitest"
+import api from "./api"
+import { ChatService } from "./chat"
+
+vi.mock("./api")
+const mockedApi = api as any
+
+describe("ChatService History Management", () => {
+  beforeEach(() => {
+    vi.resetAllMocks()
+  })
+
+  it("should list conversations", async () => {
+    const mockData = [{ id: "c1", name: "Conv 1" }]
+    mockedApi.get.mockResolvedValueOnce({ data: mockData })
+    
+    const result = await ChatService.listConversations()
+    expect(mockedApi.get).toHaveBeenCalledWith("/conversations")
+    expect(result).toEqual(mockData)
+  })
+
+  it("should create a conversation", async () => {
+    const mockData = { id: "c2", name: "New Conv" }
+    mockedApi.post.mockResolvedValueOnce({ data: mockData })
+    
+    const result = await ChatService.createConversation("New Conv")
+    expect(mockedApi.post).toHaveBeenCalledWith("/conversations", { name: "New Conv" })
+    expect(result).toEqual(mockData)
+  })
+
+  it("should rename a conversation", async () => {
+    const mockData = { id: "c1", name: "Renamed" }
+    mockedApi.patch.mockResolvedValueOnce({ data: mockData })
+    
+    const result = await ChatService.renameConversation("c1", "Renamed")
+    expect(mockedApi.patch).toHaveBeenCalledWith("/conversations/c1", { name: "Renamed" })
+    expect(result).toEqual(mockData)
+  })
+
+  it("should delete a conversation", async () => {
+    mockedApi.delete.mockResolvedValueOnce({})
+    
+    await ChatService.deleteConversation("c1")
+    expect(mockedApi.delete).toHaveBeenCalledWith("/conversations/c1")
+  })
+
+  it("should fetch messages", async () => {
+    const mockData = [{ id: "m1", content: "Hi" }]
+    mockedApi.get.mockResolvedValueOnce({ data: mockData })
+    
+    const result = await ChatService.getMessages("c1")
+    expect(mockedApi.get).toHaveBeenCalledWith("/conversations/c1/messages")
+    expect(result).toEqual(mockData)
+  })
+})