chore: revert version to 0.4.9 (#509)

* Add success toast after saving diagram

* fix: correct save toast placement

* Changes made:
1. Added i18n support
2. Fixed the issue where the save toast was running only once

* fix: show toast after download completes, not when dialog opens

Move toast from handleDrawioSave (dialog open) to saveDiagramToFile
(after download). Also restore the duplicate-save guard that was removed.

---------

Co-authored-by: Biki Kalita <86558912+Biki-dev@users.noreply.github.com>
Co-authored-by: dayuan.jiang <jdy.toh@gmail.com>

.github/workflows/electron-release.yml

@@ -38,7 +38,7 @@ jobs:
           cache: "npm"
 
       - name: Install dependencies
-        run: npm ci
+        run: npm install
 
       - name: Build and publish Electron app
         run: npm run dist:${{ matrix.platform }}

app/[lang]/page.tsx

@@ -1,6 +1,6 @@
 "use client"
 import { usePathname, useRouter } from "next/navigation"
-import { useCallback, useEffect, useRef, useState } from "react"
+import { Suspense, useCallback, useEffect, useRef, useState } from "react"
 import { DrawIoEmbed } from "react-drawio"
 import type { ImperativePanelHandle } from "react-resizable-panels"
 import ChatPanel from "@/components/chat-panel"
@@ -17,15 +17,8 @@ const drawioBaseUrl =
     process.env.NEXT_PUBLIC_DRAWIO_BASE_URL || "https://embed.diagrams.net"
 
 export default function Home() {
-    const {
-        drawioRef,
-        handleDiagramExport,
-        onDrawioLoad,
-        resetDrawioReady,
-        saveDiagramToStorage,
-        showSaveDialog,
-        setShowSaveDialog,
-    } = useDiagram()
+    const { drawioRef, handleDiagramExport, onDrawioLoad, resetDrawioReady } =
+        useDiagram()
     const router = useRouter()
     const pathname = usePathname()
     // Extract current language from pathname (e.g., "/zh/about" → "zh")
@@ -35,33 +28,12 @@ export default function Home() {
     const [drawioUi, setDrawioUi] = useState<"min" | "sketch">("min")
     const [darkMode, setDarkMode] = useState(false)
     const [isLoaded, setIsLoaded] = useState(false)
+    const [isDrawioReady, setIsDrawioReady] = useState(false)
     const [closeProtection, setCloseProtection] = useState(false)
 
     const chatPanelRef = useRef<ImperativePanelHandle>(null)
-    const isSavingRef = useRef(false)
-    const mouseOverDrawioRef = useRef(false)
     const isMobileRef = useRef(false)
 
-    // Reset saving flag when dialog closes (with delay to ignore lingering save events from draw.io)
-    useEffect(() => {
-        if (!showSaveDialog) {
-            const timeout = setTimeout(() => {
-                isSavingRef.current = false
-            }, 1000)
-            return () => clearTimeout(timeout)
-        }
-    }, [showSaveDialog])
-
-    // Handle save from draw.io's built-in save button
-    // Note: draw.io sends save events for various reasons (focus changes, etc.)
-    // We use mouse position to determine if the user is interacting with draw.io
-    const handleDrawioSave = useCallback(() => {
-        if (!mouseOverDrawioRef.current) return
-        if (isSavingRef.current) return
-        isSavingRef.current = true
-        setShowSaveDialog(true)
-    }, [setShowSaveDialog])
-
     // Load preferences from localStorage after mount
     useEffect(() => {
         // Restore saved locale and redirect if needed
@@ -104,24 +76,29 @@ export default function Home() {
         setIsLoaded(true)
     }, [pathname, router])
 
-    const handleDarkModeChange = async () => {
-        await saveDiagramToStorage()
+    const handleDrawioLoad = useCallback(() => {
+        setIsDrawioReady(true)
+        onDrawioLoad()
+    }, [onDrawioLoad])
+
+    const handleDarkModeChange = () => {
         const newValue = !darkMode
         setDarkMode(newValue)
         localStorage.setItem("next-ai-draw-io-dark-mode", String(newValue))
         document.documentElement.classList.toggle("dark", newValue)
+        setIsDrawioReady(false)
         resetDrawioReady()
     }
 
-    const handleDrawioUiChange = async () => {
-        await saveDiagramToStorage()
+    const handleDrawioUiChange = () => {
         const newUi = drawioUi === "min" ? "sketch" : "min"
         localStorage.setItem("drawio-theme", newUi)
         setDrawioUi(newUi)
+        setIsDrawioReady(false)
         resetDrawioReady()
     }
 
-    // Check mobile - save diagram and reset draw.io before crossing breakpoint
+    // Check mobile - reset draw.io before crossing breakpoint
     const isInitialRenderRef = useRef(true)
     useEffect(() => {
         const checkMobile = () => {
@@ -130,7 +107,7 @@ export default function Home() {
                 !isInitialRenderRef.current &&
                 newIsMobile !== isMobileRef.current
             ) {
-                saveDiagramToStorage().catch(() => {})
+                setIsDrawioReady(false)
                 resetDrawioReady()
             }
             isMobileRef.current = newIsMobile
@@ -141,7 +118,7 @@ export default function Home() {
         checkMobile()
         window.addEventListener("resize", checkMobile)
         return () => window.removeEventListener("resize", checkMobile)
-    }, [saveDiagramToStorage, resetDrawioReady])
+    }, [resetDrawioReady])
 
     const toggleChatPanel = () => {
         const panel = chatPanelRef.current
@@ -199,35 +176,36 @@ export default function Home() {
                         className={`h-full relative ${
                             isMobile ? "p-1" : "p-2"
                         }`}
-                        onMouseEnter={() => {
-                            mouseOverDrawioRef.current = true
-                        }}
-                        onMouseLeave={() => {
-                            mouseOverDrawioRef.current = false
-                        }}
                     >
-                        <div className="h-full rounded-xl overflow-hidden shadow-soft-lg border border-border/30">
-                            {isLoaded ? (
+                        <div className="h-full rounded-xl overflow-hidden shadow-soft-lg border border-border/30 relative">
+                            {isLoaded && (
+                                <div
+                                    className={`h-full w-full ${isDrawioReady ? "" : "invisible absolute inset-0"}`}
+                                >
                                     <DrawIoEmbed
                                         key={`${drawioUi}-${darkMode}-${currentLang}`}
                                         ref={drawioRef}
                                         onExport={handleDiagramExport}
-                                    onLoad={onDrawioLoad}
-                                    onSave={handleDrawioSave}
+                                        onLoad={handleDrawioLoad}
                                         baseUrl={drawioBaseUrl}
                                         urlParameters={{
                                             ui: drawioUi,
-                                        spin: true,
+                                            spin: false,
                                             libraries: false,
                                             saveAndExit: false,
+                                            noSaveBtn: true,
                                             noExitBtn: true,
                                             dark: darkMode,
                                             lang: currentLang,
                                         }}
                                     />
-                            ) : (
-                                <div className="h-full w-full flex items-center justify-center bg-background">
-                                    <div className="animate-spin h-8 w-8 border-4 border-primary border-t-transparent rounded-full" />
+                                </div>
+                            )}
+                            {(!isLoaded || !isDrawioReady) && (
+                                <div className="h-full w-full bg-background flex items-center justify-center">
+                                    <span className="text-muted-foreground">
+                                        Draw.io panel is loading...
+                                    </span>
                                 </div>
                             )}
                         </div>
@@ -250,6 +228,13 @@ export default function Home() {
                     onExpand={() => setIsChatVisible(true)}
                 >
                     <div className={`h-full ${isMobile ? "p-1" : "py-2 pr-2"}`}>
+                        <Suspense
+                            fallback={
+                                <div className="h-full bg-card rounded-xl border border-border/30 flex items-center justify-center text-muted-foreground">
+                                    Loading chat...
+                                </div>
+                            }
+                        >
                             <ChatPanel
                                 isVisible={isChatVisible}
                                 onToggleVisibility={toggleChatPanel}
@@ -260,6 +245,7 @@ export default function Home() {
                                 isMobile={isMobile}
                                 onCloseProtectionChange={setCloseProtection}
                             />
+                        </Suspense>
                     </div>
                 </ResizablePanel>
             </ResizablePanelGroup>

app/globals.css

@@ -74,8 +74,8 @@
     --accent: oklch(0.94 0.03 280);
     --accent-foreground: oklch(0.35 0.08 270);
 
-    /* Coral destructive */
-    --destructive: oklch(0.6 0.2 25);
+    /* Muted rose destructive */
+    --destructive: oklch(0.45 0.12 10);
 
     /* Subtle borders */
     --border: oklch(0.92 0.01 260);
@@ -122,7 +122,7 @@
     --accent: oklch(0.3 0.04 280);
     --accent-foreground: oklch(0.9 0.03 270);
 
-    --destructive: oklch(0.65 0.22 25);
+    --destructive: oklch(0.55 0.12 10);
 
     --border: oklch(0.28 0.015 260);
     --input: oklch(0.25 0.015 260);

components/chat-example-panel.tsx

@@ -70,9 +70,11 @@ function ExampleCard({
 export default function ExamplePanel({
     setInput,
     setFiles,
+    minimal = false,
 }: {
     setInput: (input: string) => void
     setFiles: (files: File[]) => void
+    minimal?: boolean
 }) {
     const dict = useDictionary()
 
@@ -120,7 +122,9 @@ export default function ExamplePanel({
     }
 
     return (
-        <div className="py-6 px-2 animate-fade-in">
+        <div className={minimal ? "" : "py-6 px-2 animate-fade-in"}>
+            {!minimal && (
+                <>
                     {/* MCP Server Notice */}
                     <a
                         href="https://github.com/DayuanJiang/next-ai-draw-io/tree/main/packages/mcp-server"
@@ -157,12 +161,16 @@ export default function ExamplePanel({
                             {dict.examples.subtitle}
                         </p>
                     </div>
+                </>
+            )}
 
             {/* Examples grid */}
             <div className="space-y-3">
+                {!minimal && (
                     <p className="text-xs font-medium text-muted-foreground uppercase tracking-wider px-1">
                         {dict.examples.quickExamples}
                     </p>
+                )}
 
                 <div className="grid gap-2">
                     <ExampleCard

components/chat-input.tsx

@@ -6,7 +6,6 @@ import {
     Image as ImageIcon,
     Loader2,
     Send,
-    Trash2,
 } from "lucide-react"
 import type React from "react"
 import { useCallback, useEffect, useRef, useState } from "react"
@@ -15,7 +14,6 @@ import { ButtonWithTooltip } from "@/components/button-with-tooltip"
 import { ErrorToast } from "@/components/error-toast"
 import { HistoryDialog } from "@/components/history-dialog"
 import { ModelSelector } from "@/components/model-selector"
-import { ResetWarningModal } from "@/components/reset-warning-modal"
 import { SaveDialog } from "@/components/save-dialog"
 
 import { Button } from "@/components/ui/button"
@@ -140,7 +138,6 @@ interface ChatInputProps {
     status: "submitted" | "streaming" | "ready" | "error"
     onSubmit: (e: React.FormEvent<HTMLFormElement>) => void
     onChange: (e: React.ChangeEvent<HTMLTextAreaElement>) => void
-    onClearChat: () => void
     files?: File[]
     onFileChange?: (files: File[]) => void
     pdfData?: Map<
@@ -163,7 +160,6 @@ export function ChatInput({
     status,
     onSubmit,
     onChange,
-    onClearChat,
     files = [],
     onFileChange = () => {},
     pdfData = new Map(),
@@ -176,14 +172,17 @@ export function ChatInput({
     onConfigureModels = () => {},
 }: ChatInputProps) {
     const dict = useDictionary()
-    const { diagramHistory, saveDiagramToFile } = useDiagram()
+    const {
+        diagramHistory,
+        saveDiagramToFile,
+        showSaveDialog,
+        setShowSaveDialog,
+    } = useDiagram()
 
     const textareaRef = useRef<HTMLTextAreaElement>(null)
     const fileInputRef = useRef<HTMLInputElement>(null)
     const [isDragging, setIsDragging] = useState(false)
-    const [showClearDialog, setShowClearDialog] = useState(false)
     const [showHistory, setShowHistory] = useState(false)
-    const [showSaveDialog, setShowSaveDialog] = useState(false)
     // Allow retry when there's an error (even if status is still "streaming" or "submitted")
     const isDisabled =
         (status === "streaming" || status === "submitted") && !error
@@ -313,11 +312,6 @@ export function ChatInput({
         }
     }
 
-    const handleClear = () => {
-        onClearChat()
-        setShowClearDialog(false)
-    }
-
     return (
         <form
             onSubmit={onSubmit}
@@ -353,36 +347,14 @@ export function ChatInput({
                     className="min-h-[60px] max-h-[200px] resize-none border-0 bg-transparent px-4 py-3 text-sm focus-visible:ring-0 focus-visible:ring-offset-0 placeholder:text-muted-foreground/60"
                 />
 
-                <div className="flex items-center justify-between px-3 py-2 border-t border-border/50">
-                    <div className="flex items-center gap-1 overflow-x-hidden">
-                        <ButtonWithTooltip
-                            type="button"
-                            variant="ghost"
-                            size="sm"
-                            onClick={() => setShowClearDialog(true)}
-                            tooltipContent={dict.chat.clearConversation}
-                            className="h-8 w-8 p-0 text-muted-foreground hover:text-destructive hover:bg-destructive/10"
-                        >
-                            <Trash2 className="h-4 w-4" />
-                        </ButtonWithTooltip>
-
-                        <ResetWarningModal
-                            open={showClearDialog}
-                            onOpenChange={setShowClearDialog}
-                            onClear={handleClear}
-                        />
-                    </div>
-
-                    <div className="flex items-center gap-1 overflow-hidden justify-end">
+                <div className="flex items-center justify-end gap-1 px-3 py-2 border-t border-border/50">
                     <div className="flex items-center gap-1 overflow-x-hidden">
                         <ButtonWithTooltip
                             type="button"
                             variant="ghost"
                             size="sm"
                             onClick={() => setShowHistory(true)}
-                                disabled={
-                                    isDisabled || diagramHistory.length === 0
-                                }
+                            disabled={isDisabled || diagramHistory.length === 0}
                             tooltipContent={dict.chat.diagramHistory}
                             className="h-8 w-8 p-0 text-muted-foreground hover:text-foreground"
                         >
@@ -452,7 +424,6 @@ export function ChatInput({
                     </Button>
                 </div>
             </div>
-            </div>
             <HistoryDialog
                 showHistory={showHistory}
                 onToggleHistory={setShowHistory}
@@ -461,7 +432,12 @@ export function ChatInput({
                 open={showSaveDialog}
                 onOpenChange={setShowSaveDialog}
                 onSave={(filename, format) =>
-                    saveDiagramToFile(filename, format, sessionId)
+                    saveDiagramToFile(
+                        filename,
+                        format,
+                        sessionId,
+                        dict.save.savedSuccessfully,
+                    )
                 }
                 defaultFilename={`diagram-${new Date()
                     .toISOString()

components/chat-message-display.tsx

@@ -7,7 +7,6 @@ import {
     ChevronDown,
     ChevronUp,
     Copy,
-    Cpu,
     FileCode,
     FileText,
     Pencil,
@@ -26,6 +25,9 @@ import {
     ReasoningContent,
     ReasoningTrigger,
 } from "@/components/ai-elements/reasoning"
+import { ChatLobby } from "@/components/chat/ChatLobby"
+import { ToolCallCard } from "@/components/chat/ToolCallCard"
+import type { DiagramOperation, ToolPartLike } from "@/components/chat/types"
 import { ScrollArea } from "@/components/ui/scroll-area"
 import { useDictionary } from "@/hooks/use-dictionary"
 import { getApiEndpoint } from "@/lib/base-path"
@@ -33,18 +35,10 @@ import {
     applyDiagramOperations,
     convertToLegalXml,
     extractCompleteMxCells,
-    isMxCellXmlComplete,
     replaceNodes,
     validateAndFixXml,
 } from "@/lib/utils"
 import ExamplePanel from "./chat-example-panel"
-import { CodeBlock } from "./code-block"
-
-interface DiagramOperation {
-    operation: "update" | "add" | "delete"
-    cell_id: string
-    new_xml?: string
-}
 
 // Helper to extract complete operations from streaming input
 function getCompleteOperations(
@@ -58,60 +52,10 @@ function getCompleteOperations(
             ["update", "add", "delete"].includes(op.operation) &&
             typeof op.cell_id === "string" &&
             op.cell_id.length > 0 &&
-            // delete doesn't need new_xml, update/add do
             (op.operation === "delete" || typeof op.new_xml === "string"),
     )
 }
 
-// Tool part interface for type safety
-interface ToolPartLike {
-    type: string
-    toolCallId: string
-    state?: string
-    input?: {
-        xml?: string
-        operations?: DiagramOperation[]
-    } & Record<string, unknown>
-    output?: string
-}
-
-function OperationsDisplay({ operations }: { operations: DiagramOperation[] }) {
-    return (
-        <div className="space-y-3">
-            {operations.map((op, index) => (
-                <div
-                    key={`${op.operation}-${op.cell_id}-${index}`}
-                    className="rounded-lg border border-border/50 overflow-hidden bg-background/50"
-                >
-                    <div className="px-3 py-1.5 bg-muted/40 border-b border-border/30 flex items-center gap-2">
-                        <span
-                            className={`text-[10px] font-medium uppercase tracking-wide ${
-                                op.operation === "delete"
-                                    ? "text-red-600"
-                                    : op.operation === "add"
-                                      ? "text-green-600"
-                                      : "text-blue-600"
-                            }`}
-                        >
-                            {op.operation}
-                        </span>
-                        <span className="text-xs text-muted-foreground">
-                            cell_id: {op.cell_id}
-                        </span>
-                    </div>
-                    {op.new_xml && (
-                        <div className="px-3 py-2">
-                            <pre className="text-[11px] font-mono text-foreground/80 bg-muted/30 rounded px-2 py-1.5 overflow-x-auto whitespace-pre-wrap break-all">
-                                {op.new_xml}
-                            </pre>
-                        </div>
-                    )}
-                </div>
-            ))}
-        </div>
-    )
-}
-
 import { useDiagram } from "@/contexts/diagram-context"
 
 // Helper to split text content into regular text and file sections (PDF or text files)
@@ -183,6 +127,13 @@ const getUserOriginalText = (message: UIMessage): string => {
     return fullText.replace(filePattern, "").trim()
 }
 
+interface SessionMetadata {
+    id: string
+    title: string
+    updatedAt: number
+    thumbnailDataUrl?: string
+}
+
 interface ChatMessageDisplayProps {
     messages: UIMessage[]
     setInput: (input: string) => void
@@ -193,6 +144,11 @@ interface ChatMessageDisplayProps {
     onRegenerate?: (messageIndex: number) => void
     onEditMessage?: (messageIndex: number, newText: string) => void
     status?: "streaming" | "submitted" | "idle" | "error" | "ready"
+    isRestored?: boolean
+    sessions?: SessionMetadata[]
+    onSelectSession?: (id: string) => void
+    onDeleteSession?: (id: string) => void
+    loadedMessageIdsRef?: MutableRefObject<Set<string>>
 }
 
 export function ChatMessageDisplay({
@@ -205,14 +161,33 @@ export function ChatMessageDisplay({
     onRegenerate,
     onEditMessage,
     status = "idle",
+    isRestored = false,
+    sessions = [],
+    onSelectSession,
+    onDeleteSession,
+    loadedMessageIdsRef,
 }: ChatMessageDisplayProps) {
     const dict = useDictionary()
     const { chartXML, loadDiagram: onDisplayChart } = useDiagram()
     const messagesEndRef = useRef<HTMLDivElement>(null)
+    const scrollTopRef = useRef<HTMLDivElement>(null)
     const previousXML = useRef<string>("")
     const processedToolCalls = processedToolCallsRef
     // Track the last processed XML per toolCallId to skip redundant processing during streaming
     const lastProcessedXmlRef = useRef<Map<string, string>>(new Map())
+
+    // Reset refs when messages become empty (new chat or session switch)
+    // This ensures cached examples work correctly after starting a new session
+    useEffect(() => {
+        if (messages.length === 0) {
+            previousXML.current = ""
+            lastProcessedXmlRef.current.clear()
+            // Note: processedToolCalls is passed from parent, so we clear it too
+            processedToolCalls.current.clear()
+            // Scroll to top to show newest history items
+            scrollTopRef.current?.scrollIntoView({ behavior: "instant" })
+        }
+    }, [messages.length, processedToolCalls])
     // Debounce streaming diagram updates - store pending XML and timeout
     const pendingXmlRef = useRef<string | null>(null)
     const debounceTimeoutRef = useRef<ReturnType<typeof setTimeout> | null>(
@@ -347,7 +322,6 @@ export function ChatMessageDisplay({
     const handleDisplayChart = useCallback(
         (xml: string, showToast = false) => {
             let currentXml = xml || ""
-            const startTime = performance.now()
 
             // During streaming (showToast=false), extract only complete mxCell elements
             // This allows progressive rendering even with partial/incomplete trailing XML
@@ -371,14 +345,8 @@ export function ChatMessageDisplay({
                 const parseError = testDoc.querySelector("parsererror")
 
                 if (parseError) {
-                    // Use console.warn instead of console.error to avoid triggering
-                    // Next.js dev mode error overlay for expected streaming states
-                    // (partial XML during streaming is normal and will be fixed by subsequent updates)
+                    // Only show toast if this is the final XML (not during streaming)
                     if (showToast) {
-                        // Only log as error and show toast if this is the final XML
-                        console.error(
-                            "[ChatMessageDisplay] Malformed XML detected in final output",
-                        )
                         toast.error(dict.errors.malformedXml)
                     }
                     return // Skip this update
@@ -392,18 +360,12 @@ export function ChatMessageDisplay({
                         `<mxfile><diagram name="Page-1" id="page-1"><mxGraphModel><root><mxCell id="0"/><mxCell id="1" parent="0"/></root></mxGraphModel></diagram></mxfile>`
                     const replacedXML = replaceNodes(baseXML, convertedXml)
 
-                    const xmlProcessTime = performance.now() - startTime
-
                     // During streaming (showToast=false), skip heavy validation for lower latency
                     // The quick DOM parse check above catches malformed XML
                     // Full validation runs on final output (showToast=true)
                     if (!showToast) {
                         previousXML.current = convertedXml
-                        const loadStartTime = performance.now()
                         onDisplayChart(replacedXML, true)
-                        console.log(
-                            `[Streaming] XML processing: ${xmlProcessTime.toFixed(1)}ms, drawio load: ${(performance.now() - loadStartTime).toFixed(1)}ms`,
-                        )
                         return
                     }
 
@@ -413,30 +375,12 @@ export function ChatMessageDisplay({
                         previousXML.current = convertedXml
                         // Use fixed XML if available, otherwise use original
                         const xmlToLoad = validation.fixed || replacedXML
-                        if (validation.fixes.length > 0) {
-                            console.log(
-                                "[ChatMessageDisplay] Auto-fixed XML issues:",
-                                validation.fixes,
-                            )
-                        }
-                        // Skip validation in loadDiagram since we already validated above
-                        const loadStartTime = performance.now()
                         onDisplayChart(xmlToLoad, true)
-                        console.log(
-                            `[Final] XML processing: ${xmlProcessTime.toFixed(1)}ms, validation+load: ${(performance.now() - loadStartTime).toFixed(1)}ms`,
-                        )
                     } else {
-                        console.error(
-                            "[ChatMessageDisplay] XML validation failed:",
-                            validation.error,
-                        )
                         toast.error(dict.errors.validationFailed)
                     }
                 } catch (error) {
-                    console.error(
-                        "[ChatMessageDisplay] Error processing XML:",
-                        error,
-                    )
+                    console.error("Error processing XML:", error)
                     // Only show toast if this is the final XML (not during streaming)
                     if (showToast) {
                         toast.error(dict.errors.failedToProcess)
@@ -447,8 +391,22 @@ export function ChatMessageDisplay({
         [chartXML, onDisplayChart],
     )
 
+    // Track previous message count to detect bulk loads vs streaming
+    const prevMessageCountRef = useRef(0)
+
     useEffect(() => {
-        if (messagesEndRef.current) {
+        if (messagesEndRef.current && messages.length > 0) {
+            const prevCount = prevMessageCountRef.current
+            const currentCount = messages.length
+            prevMessageCountRef.current = currentCount
+
+            // Bulk load (session restore) - instant scroll, no animation
+            if (prevCount === 0 || currentCount - prevCount > 1) {
+                messagesEndRef.current.scrollIntoView({ behavior: "instant" })
+                return
+            }
+
+            // Single message added - smooth scroll
             messagesEndRef.current.scrollIntoView({ behavior: "smooth" })
         }
     }, [messages])
@@ -666,202 +624,19 @@ export function ChatMessageDisplay({
         // Let the timeouts complete naturally - they're harmless if component unmounts.
     }, [messages, handleDisplayChart, chartXML])
 
-    const renderToolPart = (part: ToolPartLike) => {
-        const callId = part.toolCallId
-        const { state, input, output } = part
-        const isExpanded = expandedTools[callId] ?? true
-        const toolName = part.type?.replace("tool-", "")
-        const isCopied = copiedToolCallId === callId
-
-        const toggleExpanded = () => {
-            setExpandedTools((prev) => ({
-                ...prev,
-                [callId]: !isExpanded,
-            }))
-        }
-
-        const getToolDisplayName = (name: string) => {
-            switch (name) {
-                case "display_diagram":
-                    return "Generate Diagram"
-                case "edit_diagram":
-                    return "Edit Diagram"
-                case "get_shape_library":
-                    return "Get Shape Library"
-                default:
-                    return name
-            }
-        }
-
-        const handleCopy = () => {
-            let textToCopy = ""
-
-            if (input && typeof input === "object") {
-                if (input.xml) {
-                    textToCopy = input.xml
-                } else if (
-                    input.operations &&
-                    Array.isArray(input.operations)
-                ) {
-                    textToCopy = JSON.stringify(input.operations, null, 2)
-                } else if (Object.keys(input).length > 0) {
-                    textToCopy = JSON.stringify(input, null, 2)
-                }
-            }
-
-            if (
-                output &&
-                toolName === "get_shape_library" &&
-                typeof output === "string"
-            ) {
-                textToCopy = output
-            }
-
-            if (textToCopy) {
-                copyMessageToClipboard(callId, textToCopy, true)
-            }
-        }
-
-        return (
-            <div
-                key={callId}
-                className="my-3 rounded-xl border border-border/60 bg-muted/30 overflow-hidden"
-            >
-                <div className="flex items-center justify-between px-4 py-3 bg-muted/50">
-                    <div className="flex items-center gap-2">
-                        <div className="w-6 h-6 rounded-md bg-primary/10 flex items-center justify-center">
-                            <Cpu className="w-3.5 h-3.5 text-primary" />
-                        </div>
-                        <span className="text-sm font-medium text-foreground/80">
-                            {getToolDisplayName(toolName)}
-                        </span>
-                    </div>
-                    <div className="flex items-center gap-2">
-                        {state === "input-streaming" && (
-                            <div className="h-4 w-4 border-2 border-primary border-t-transparent rounded-full animate-spin" />
-                        )}
-                        {state === "output-available" && (
-                            <>
-                                <span className="text-xs font-medium text-green-600 bg-green-50 px-2 py-0.5 rounded-full">
-                                    {dict.tools.complete}
-                                </span>
-                                {isExpanded && (
-                                    <button
-                                        type="button"
-                                        onClick={handleCopy}
-                                        className="p-1 rounded hover:bg-muted transition-colors"
-                                        title={
-                                            copiedToolCallId === callId
-                                                ? dict.chat.copied
-                                                : copyFailedToolCallId ===
-                                                    callId
-                                                  ? dict.chat.failedToCopy
-                                                  : dict.chat.copyResponse
-                                        }
-                                    >
-                                        {isCopied ? (
-                                            <Check className="w-4 h-4 text-green-600" />
-                                        ) : (
-                                            <Copy className="w-4 h-4 text-muted-foreground" />
-                                        )}
-                                    </button>
-                                )}
-                            </>
-                        )}
-                        {state === "output-error" &&
-                            (() => {
-                                // Check if this is a truncation (incomplete XML) vs real error
-                                const isTruncated =
-                                    (toolName === "display_diagram" ||
-                                        toolName === "append_diagram") &&
-                                    !isMxCellXmlComplete(input?.xml)
-                                return isTruncated ? (
-                                    <span className="text-xs font-medium text-yellow-600 bg-yellow-50 px-2 py-0.5 rounded-full">
-                                        Truncated
-                                    </span>
-                                ) : (
-                                    <span className="text-xs font-medium text-red-600 bg-red-50 px-2 py-0.5 rounded-full">
-                                        Error
-                                    </span>
-                                )
-                            })()}
-                        {input && Object.keys(input).length > 0 && (
-                            <button
-                                type="button"
-                                onClick={toggleExpanded}
-                                className="p-1 rounded hover:bg-muted transition-colors"
-                            >
-                                {isExpanded ? (
-                                    <ChevronUp className="w-4 h-4 text-muted-foreground" />
-                                ) : (
-                                    <ChevronDown className="w-4 h-4 text-muted-foreground" />
-                                )}
-                            </button>
-                        )}
-                    </div>
-                </div>
-                {input && isExpanded && (
-                    <div className="px-4 py-3 border-t border-border/40 bg-muted/20">
-                        {typeof input === "object" && input.xml ? (
-                            <CodeBlock code={input.xml} language="xml" />
-                        ) : typeof input === "object" &&
-                          input.operations &&
-                          Array.isArray(input.operations) ? (
-                            <OperationsDisplay operations={input.operations} />
-                        ) : typeof input === "object" &&
-                          Object.keys(input).length > 0 ? (
-                            <CodeBlock
-                                code={JSON.stringify(input, null, 2)}
-                                language="json"
-                            />
-                        ) : null}
-                    </div>
-                )}
-                {output &&
-                    state === "output-error" &&
-                    (() => {
-                        const isTruncated =
-                            (toolName === "display_diagram" ||
-                                toolName === "append_diagram") &&
-                            !isMxCellXmlComplete(input?.xml)
-                        return (
-                            <div
-                                className={`px-4 py-3 border-t border-border/40 text-sm ${isTruncated ? "text-yellow-600" : "text-red-600"}`}
-                            >
-                                {isTruncated
-                                    ? "Output truncated due to length limits. Try a simpler request or increase the maxOutputLength."
-                                    : output}
-                            </div>
-                        )
-                    })()}
-                {/* Show get_shape_library output on success */}
-                {output &&
-                    toolName === "get_shape_library" &&
-                    state === "output-available" &&
-                    isExpanded && (
-                        <div className="px-4 py-3 border-t border-border/40">
-                            <div className="text-xs text-muted-foreground mb-2">
-                                Library loaded (
-                                {typeof output === "string" ? output.length : 0}{" "}
-                                chars)
-                            </div>
-                            <pre className="text-xs bg-muted/50 p-2 rounded-md overflow-auto max-h-32 whitespace-pre-wrap">
-                                {typeof output === "string"
-                                    ? output.substring(0, 800) +
-                                      (output.length > 800 ? "\n..." : "")
-                                    : String(output)}
-                            </pre>
-                        </div>
-                    )}
-            </div>
-        )
-    }
-
     return (
         <ScrollArea className="h-full w-full scrollbar-thin">
-            {messages.length === 0 ? (
-                <ExamplePanel setInput={setInput} setFiles={setFiles} />
-            ) : (
+            <div ref={scrollTopRef} />
+            {messages.length === 0 && isRestored ? (
+                <ChatLobby
+                    sessions={sessions}
+                    onSelectSession={onSelectSession || (() => {})}
+                    onDeleteSession={onDeleteSession}
+                    setInput={setInput}
+                    setFiles={setFiles}
+                    dict={dict}
+                />
+            ) : messages.length === 0 ? null : (
                 <div className="py-4 px-4 space-y-4">
                     {messages.map((message, messageIndex) => {
                         const userMessageText =
@@ -881,13 +656,21 @@ export function ChatMessageDisplay({
                                     .slice(messageIndex + 1)
                                     .every((m) => m.role !== "user"))
                         const isEditing = editingMessageId === message.id
+                        // Skip animation for loaded messages (from session restore)
+                        const isRestoredMessage =
+                            loadedMessageIdsRef?.current.has(message.id) ??
+                            false
                         return (
                             <div
                                 key={message.id}
-                                className={`flex w-full ${message.role === "user" ? "justify-end" : "justify-start"} animate-message-in`}
-                                style={{
+                                className={`flex w-full ${message.role === "user" ? "justify-end" : "justify-start"} ${isRestoredMessage ? "" : "animate-message-in"}`}
+                                style={
+                                    isRestoredMessage
+                                        ? undefined
+                                        : {
                                               animationDelay: `${messageIndex * 50}ms`,
-                                }}
+                                          }
+                                }
                             >
                                 {message.role === "user" &&
                                     userMessageText &&
@@ -984,6 +767,9 @@ export function ChatMessageDisplay({
                                                             isStreaming={
                                                                 isStreamingReasoning
                                                             }
+                                                            defaultOpen={
+                                                                !isRestoredMessage
+                                                            }
                                                         >
                                                             <ReasoningTrigger />
                                                             <ReasoningContent>
@@ -1126,9 +912,30 @@ export function ChatMessageDisplay({
                                             return groups.map(
                                                 (group, groupIndex) => {
                                                     if (group.type === "tool") {
-                                                        return renderToolPart(
+                                                        return (
+                                                            <ToolCallCard
+                                                                key={`${message.id}-tool-${group.startIndex}`}
+                                                                part={
                                                                     group
-                                                                .parts[0] as ToolPartLike,
+                                                                        .parts[0] as ToolPartLike
+                                                                }
+                                                                expandedTools={
+                                                                    expandedTools
+                                                                }
+                                                                setExpandedTools={
+                                                                    setExpandedTools
+                                                                }
+                                                                onCopy={
+                                                                    copyMessageToClipboard
+                                                                }
+                                                                copiedToolCallId={
+                                                                    copiedToolCallId
+                                                                }
+                                                                copyFailedToolCallId={
+                                                                    copyFailedToolCallId
+                                                                }
+                                                                dict={dict}
+                                                            />
                                                         )
                                                     }
 

components/chat-panel.tsx

@@ -9,34 +9,39 @@ import {
     Settings,
 } from "lucide-react"
 import Image from "next/image"
+import { useRouter, useSearchParams } from "next/navigation"
 import type React from "react"
-import { useCallback, useEffect, useRef, useState } from "react"
+import {
+    useCallback,
+    useEffect,
+    useLayoutEffect,
+    useRef,
+    useState,
+} from "react"
 import { flushSync } from "react-dom"
 import { Toaster, toast } from "sonner"
 import { ButtonWithTooltip } from "@/components/button-with-tooltip"
 import { ChatInput } from "@/components/chat-input"
 import { ModelConfigDialog } from "@/components/model-config-dialog"
-import { ResetWarningModal } from "@/components/reset-warning-modal"
 import { SettingsDialog } from "@/components/settings-dialog"
 import { useDiagram } from "@/contexts/diagram-context"
 import { useDiagramToolHandlers } from "@/hooks/use-diagram-tool-handlers"
 import { useDictionary } from "@/hooks/use-dictionary"
 import { getSelectedAIConfig, useModelConfig } from "@/hooks/use-model-config"
+import { useSessionManager } from "@/hooks/use-session-manager"
 import { getApiEndpoint } from "@/lib/base-path"
 import { findCachedResponse } from "@/lib/cached-responses"
 import { formatMessage } from "@/lib/i18n/utils"
 import { isPdfFile, isTextFile } from "@/lib/pdf-utils"
+import { sanitizeMessages } from "@/lib/session-storage"
 import { type FileData, useFileProcessor } from "@/lib/use-file-processor"
 import { useQuotaManager } from "@/lib/use-quota-manager"
-import { formatXML } from "@/lib/utils"
+import { cn, formatXML, isRealDiagram } from "@/lib/utils"
 import { ChatMessageDisplay } from "./chat-message-display"
 import { DevXmlSimulator } from "./dev-xml-simulator"
 
 // localStorage keys for persistence
-const STORAGE_MESSAGES_KEY = "next-ai-draw-io-messages"
-const STORAGE_XML_SNAPSHOTS_KEY = "next-ai-draw-io-xml-snapshots"
 const STORAGE_SESSION_ID_KEY = "next-ai-draw-io-session-id"
-export const STORAGE_DIAGRAM_XML_KEY = "next-ai-draw-io-diagram-xml"
 
 // sessionStorage keys
 const SESSION_STORAGE_INPUT_KEY = "next-ai-draw-io-input"
@@ -113,10 +118,17 @@ export default function ChatPanel({
         handleExportWithoutHistory,
         resolverRef,
         chartXML,
+        latestSvg,
         clearDiagram,
+        getThumbnailSvg,
+        diagramHistory,
+        setDiagramHistory,
     } = useDiagram()
 
     const dict = useDictionary()
+    const router = useRouter()
+    const searchParams = useSearchParams()
+    const urlSessionId = searchParams.get("session")
 
     const onFetchChart = (saveToHistory = true) => {
         return Promise.race([
@@ -152,11 +164,14 @@ export default function ChatPanel({
 
     // Model configuration hook
     const modelConfig = useModelConfig()
+
+    // Session manager for chat history (pass URL session ID for restoration)
+    const sessionManager = useSessionManager({ initialSessionId: urlSessionId })
+
     const [input, setInput] = useState("")
     const [dailyRequestLimit, setDailyRequestLimit] = useState(0)
     const [dailyTokenLimit, setDailyTokenLimit] = useState(0)
     const [tpmLimit, setTpmLimit] = useState(0)
-    const [showNewChatDialog, setShowNewChatDialog] = useState(false)
     const [minimalStyle, setMinimalStyle] = useState(false)
 
     // Restore input from sessionStorage on mount (when ChatPanel remounts due to key change)
@@ -201,13 +216,37 @@ export default function ChatPanel({
 
     // Flag to track if we've restored from localStorage
     const hasRestoredRef = useRef(false)
+    const [isRestored, setIsRestored] = useState(false)
+
+    // Track previous isVisible to only animate when toggling (not on page load)
+    const prevIsVisibleRef = useRef(isVisible)
+    const [shouldAnimatePanel, setShouldAnimatePanel] = useState(false)
+    useEffect(() => {
+        // Only animate when visibility changes from false to true (not on initial load)
+        if (!prevIsVisibleRef.current && isVisible) {
+            setShouldAnimatePanel(true)
+        }
+        prevIsVisibleRef.current = isVisible
+    }, [isVisible])
 
     // Ref to track latest chartXML for use in callbacks (avoids stale closure)
     const chartXMLRef = useRef(chartXML)
+    // Track session ID that was loaded without a diagram (to prevent thumbnail contamination)
+    const justLoadedSessionIdRef = useRef<string | null>(null)
     useEffect(() => {
         chartXMLRef.current = chartXML
+        // Clear the no-diagram flag when a diagram is generated
+        if (chartXML) {
+            justLoadedSessionIdRef.current = null
+        }
     }, [chartXML])
 
+    // Ref to track latest SVG for thumbnail generation
+    const latestSvgRef = useRef(latestSvg)
+    useEffect(() => {
+        latestSvgRef.current = latestSvg
+    }, [latestSvg])
+
     // Ref to track consecutive auto-retry count (reset on user action)
     const autoRetryCountRef = useRef(0)
     // Ref to track continuation retry count (for truncation handling)
@@ -289,32 +328,6 @@ export default function ChatPanel({
                 // Silence access code error in console since it's handled by UI
                 if (!error.message.includes("Invalid or missing access code")) {
                     console.error("Chat error:", error)
-                    // Debug: Log messages structure when error occurs
-                    console.log("[onError] messages count:", messages.length)
-                    messages.forEach((msg, idx) => {
-                        console.log(`[onError] Message ${idx}:`, {
-                            role: msg.role,
-                            partsCount: msg.parts?.length,
-                        })
-                        if (msg.parts) {
-                            msg.parts.forEach((part: any, partIdx: number) => {
-                                console.log(
-                                    `[onError]   Part ${partIdx}:`,
-                                    JSON.stringify({
-                                        type: part.type,
-                                        toolName: part.toolName,
-                                        hasInput: !!part.input,
-                                        inputType: typeof part.input,
-                                        inputKeys:
-                                            part.input &&
-                                            typeof part.input === "object"
-                                                ? Object.keys(part.input)
-                                                : null,
-                                    }),
-                                )
-                            })
-                        }
-                    })
                 }
 
                 // Translate technical errors into user-friendly messages
@@ -360,15 +373,7 @@ export default function ChatPanel({
                     setShowSettingsDialog(true)
                 }
             },
-            onFinish: ({ message }) => {
-                // Track actual token usage from server metadata
-                const metadata = message?.metadata as
-                    | Record<string, unknown>
-                    | undefined
-
-                // DEBUG: Log finish reason to diagnose truncation
-                console.log("[onFinish] finishReason:", metadata?.finishReason)
-            },
+            onFinish: () => {},
             sendAutomaticallyWhen: ({ messages }) => {
                 const isInContinuationMode = partialXmlRef.current.length > 0
 
@@ -426,58 +431,199 @@ export default function ChatPanel({
         messagesRef.current = messages
     }, [messages])
 
-    const messagesEndRef = useRef<HTMLDivElement>(null)
+    // Track last synced session ID to detect external changes (e.g., URL back/forward)
+    const lastSyncedSessionIdRef = useRef<string | null>(null)
 
-    // Restore messages and XML snapshots from localStorage on mount
-    useEffect(() => {
+    // Helper: Sync UI state with session data (eliminates duplication)
+    // Track message IDs that are being loaded from session (to skip animations/scroll)
+    const loadedMessageIdsRef = useRef<Set<string>>(new Set())
+    // Track when session was just loaded (to skip auto-save on load)
+    const justLoadedSessionRef = useRef(false)
+
+    const syncUIWithSession = useCallback(
+        (
+            data: {
+                messages: unknown[]
+                xmlSnapshots: [number, string][]
+                diagramXml: string
+                diagramHistory?: { svg: string; xml: string }[]
+            } | null,
+        ) => {
+            const hasRealDiagram = isRealDiagram(data?.diagramXml)
+            if (data) {
+                // Mark all message IDs as loaded from session
+                const messageIds = (data.messages as any[]).map(
+                    (m: any) => m.id,
+                )
+                loadedMessageIdsRef.current = new Set(messageIds)
+                setMessages(data.messages as any)
+                xmlSnapshotsRef.current = new Map(data.xmlSnapshots)
+                if (hasRealDiagram) {
+                    onDisplayChart(data.diagramXml, true)
+                    chartXMLRef.current = data.diagramXml
+                } else {
+                    clearDiagram()
+                    // Clear refs to prevent stale data from being saved
+                    chartXMLRef.current = ""
+                    latestSvgRef.current = ""
+                }
+                setDiagramHistory(data.diagramHistory || [])
+            } else {
+                loadedMessageIdsRef.current = new Set()
+                setMessages([])
+                xmlSnapshotsRef.current.clear()
+                clearDiagram()
+                // Clear refs to prevent stale data from being saved
+                chartXMLRef.current = ""
+                latestSvgRef.current = ""
+                setDiagramHistory([])
+            }
+        },
+        [setMessages, onDisplayChart, clearDiagram, setDiagramHistory],
+    )
+
+    // Helper: Build session data object for saving (eliminates duplication)
+    const buildSessionData = useCallback(
+        async (options: { withThumbnail?: boolean } = {}) => {
+            const currentDiagramXml = chartXMLRef.current || ""
+            // Only capture thumbnail if there's a meaningful diagram (not just empty template)
+            const hasRealDiagram = isRealDiagram(currentDiagramXml)
+            let thumbnailDataUrl: string | undefined
+            if (hasRealDiagram && options.withThumbnail) {
+                const freshThumb = await getThumbnailSvg()
+                if (freshThumb) {
+                    latestSvgRef.current = freshThumb
+                    thumbnailDataUrl = freshThumb
+                } else if (latestSvgRef.current) {
+                    // Use cached thumbnail only if we have a real diagram
+                    thumbnailDataUrl = latestSvgRef.current
+                }
+            }
+            return {
+                messages: sanitizeMessages(messagesRef.current),
+                xmlSnapshots: Array.from(xmlSnapshotsRef.current.entries()),
+                diagramXml: currentDiagramXml,
+                thumbnailDataUrl,
+                diagramHistory,
+            }
+        },
+        [diagramHistory, getThumbnailSvg],
+    )
+
+    // Restore messages and XML snapshots from session manager on mount
+    // This effect syncs with the session manager's loaded session
+    useLayoutEffect(() => {
         if (hasRestoredRef.current) return
+        if (sessionManager.isLoading) return // Wait for session manager to load
+
         hasRestoredRef.current = true
 
         try {
-            // Restore messages
-            const savedMessages = localStorage.getItem(STORAGE_MESSAGES_KEY)
-            if (savedMessages) {
-                const parsed = JSON.parse(savedMessages)
-                if (Array.isArray(parsed) && parsed.length > 0) {
-                    setMessages(parsed)
-                }
-            }
-
-            // Restore XML snapshots
-            const savedSnapshots = localStorage.getItem(
-                STORAGE_XML_SNAPSHOTS_KEY,
-            )
-            if (savedSnapshots) {
-                const parsed = JSON.parse(savedSnapshots)
-                xmlSnapshotsRef.current = new Map(parsed)
+            const currentSession = sessionManager.currentSession
+            if (currentSession && currentSession.messages.length > 0) {
+                // Restore from session manager (IndexedDB)
+                justLoadedSessionRef.current = true
+                syncUIWithSession(currentSession)
             }
+            // Initialize lastSyncedSessionIdRef to prevent sync effect from firing immediately
+            lastSyncedSessionIdRef.current = sessionManager.currentSessionId
+            // Note: Migration from old localStorage format is handled by session-storage.ts
         } catch (error) {
-            console.error("Failed to restore from localStorage:", error)
-            // On complete failure, clear storage to allow recovery
-            localStorage.removeItem(STORAGE_MESSAGES_KEY)
-            localStorage.removeItem(STORAGE_XML_SNAPSHOTS_KEY)
+            console.error("Failed to restore session:", error)
             toast.error(dict.errors.sessionCorrupted)
+        } finally {
+            setIsRestored(true)
         }
-    }, [setMessages])
+    }, [
+        sessionManager.isLoading,
+        sessionManager.currentSession,
+        syncUIWithSession,
+        dict.errors.sessionCorrupted,
+    ])
+
+    // Sync UI when session changes externally (e.g., URL navigation via back/forward)
+    // This handles changes AFTER initial restore
+    useEffect(() => {
+        if (!isRestored) return // Wait for initial restore to complete
+        if (!sessionManager.isAvailable) return
+
+        const newSessionId = sessionManager.currentSessionId
+        const newSession = sessionManager.currentSession
+
+        // Skip if session ID hasn't changed (our own saves don't change the ID)
+        if (newSessionId === lastSyncedSessionIdRef.current) return
+
+        // Update last synced ID
+        lastSyncedSessionIdRef.current = newSessionId
+
+        // Sync UI with new session
+        if (newSession && newSession.messages.length > 0) {
+            justLoadedSessionRef.current = true
+            syncUIWithSession(newSession)
+        } else if (!newSession) {
+            syncUIWithSession(null)
+        }
+    }, [
+        isRestored,
+        sessionManager.isAvailable,
+        sessionManager.currentSessionId,
+        sessionManager.currentSession,
+        syncUIWithSession,
+    ])
+
+    // Save messages to session manager (debounced, only when not streaming)
+    // Destructure stable values to avoid effect re-running on every render
+    const {
+        isAvailable: sessionIsAvailable,
+        currentSessionId,
+        saveCurrentSession,
+    } = sessionManager
+
+    // Use ref for saveCurrentSession to avoid infinite loop
+    // (saveCurrentSession changes after each save, which would re-trigger the effect)
+    const saveCurrentSessionRef = useRef(saveCurrentSession)
+    saveCurrentSessionRef.current = saveCurrentSession
 
-    // Save messages to localStorage whenever they change (debounced to prevent blocking during streaming)
     useEffect(() => {
         if (!hasRestoredRef.current) return
+        if (!sessionIsAvailable) return
+        // Only save when not actively streaming to avoid write storms
+        if (status === "streaming" || status === "submitted") return
+
+        // Skip auto-save if session was just loaded (to prevent re-ordering)
+        if (justLoadedSessionRef.current) {
+            justLoadedSessionRef.current = false
+            return
+        }
 
         // Clear any pending save
         if (localStorageDebounceRef.current) {
             clearTimeout(localStorageDebounceRef.current)
         }
 
+        // Capture current session ID at schedule time to verify at save time
+        const scheduledForSessionId = currentSessionId
+        // Capture whether there's a REAL diagram NOW (not just empty template)
+        const hasDiagramNow = isRealDiagram(chartXMLRef.current)
+        // Check if this session was just loaded without a diagram
+        const isNodiagramSession =
+            justLoadedSessionIdRef.current === scheduledForSessionId
+
         // Debounce: save after 1 second of no changes
-        localStorageDebounceRef.current = setTimeout(() => {
+        localStorageDebounceRef.current = setTimeout(async () => {
             try {
-                localStorage.setItem(
-                    STORAGE_MESSAGES_KEY,
-                    JSON.stringify(messages),
+                if (messages.length > 0) {
+                    const sessionData = await buildSessionData({
+                        // Only capture thumbnail if there was a diagram AND this isn't a no-diagram session
+                        withThumbnail: hasDiagramNow && !isNodiagramSession,
+                    })
+                    await saveCurrentSessionRef.current(
+                        sessionData,
+                        scheduledForSessionId,
                     )
+                }
             } catch (error) {
-                console.error("Failed to save messages to localStorage:", error)
+                console.error("Failed to save session:", error)
             }
         }, LOCAL_STORAGE_DEBOUNCE_MS)
 
@@ -487,63 +633,62 @@ export default function ChatPanel({
                 clearTimeout(localStorageDebounceRef.current)
             }
         }
-    }, [messages])
+    }, [
+        messages,
+        status,
+        sessionIsAvailable,
+        currentSessionId,
+        buildSessionData,
+    ])
 
-    // Save XML snapshots to localStorage whenever they change
-    const saveXmlSnapshots = useCallback(() => {
-        try {
-            const snapshotsArray = Array.from(xmlSnapshotsRef.current.entries())
-            localStorage.setItem(
-                STORAGE_XML_SNAPSHOTS_KEY,
-                JSON.stringify(snapshotsArray),
-            )
-        } catch (error) {
-            console.error(
-                "Failed to save XML snapshots to localStorage:",
-                error,
-            )
+    // Update URL when a new session is created (first message sent)
+    useEffect(() => {
+        if (sessionManager.currentSessionId && !urlSessionId) {
+            // A session was created but URL doesn't have the session param yet
+            router.replace(`?session=${sessionManager.currentSessionId}`, {
+                scroll: false,
+            })
         }
-    }, [])
+    }, [sessionManager.currentSessionId, urlSessionId, router])
 
     // Save session ID to localStorage
     useEffect(() => {
         localStorage.setItem(STORAGE_SESSION_ID_KEY, sessionId)
     }, [sessionId])
 
+    // Save session when page becomes hidden (tab switch, close, navigate away)
+    // This is more reliable than beforeunload for async IndexedDB operations
     useEffect(() => {
-        if (messagesEndRef.current) {
-            messagesEndRef.current.scrollIntoView({ behavior: "smooth" })
-        }
-    }, [messages])
+        if (!sessionManager.isAvailable) return
 
-    // Save state right before page unload (refresh/close)
-    useEffect(() => {
-        const handleBeforeUnload = () => {
+        const handleVisibilityChange = async () => {
+            if (
+                document.visibilityState === "hidden" &&
+                messagesRef.current.length > 0
+            ) {
                 try {
-                localStorage.setItem(
-                    STORAGE_MESSAGES_KEY,
-                    JSON.stringify(messagesRef.current),
-                )
-                localStorage.setItem(
-                    STORAGE_XML_SNAPSHOTS_KEY,
-                    JSON.stringify(
-                        Array.from(xmlSnapshotsRef.current.entries()),
-                    ),
-                )
-                const xml = chartXMLRef.current
-                if (xml && xml.length > 300) {
-                    localStorage.setItem(STORAGE_DIAGRAM_XML_KEY, xml)
-                }
-                localStorage.setItem(STORAGE_SESSION_ID_KEY, sessionId)
+                    // Attempt to save session - browser may not wait for completion
+                    // Skip thumbnail capture as it may not complete in time
+                    const sessionData = await buildSessionData({
+                        withThumbnail: false,
+                    })
+                    await sessionManager.saveCurrentSession(sessionData)
                 } catch (error) {
-                console.error("Failed to persist state before unload:", error)
+                    console.error(
+                        "Failed to save session on visibility change:",
+                        error,
+                    )
+                }
             }
         }
 
-        window.addEventListener("beforeunload", handleBeforeUnload)
+        document.addEventListener("visibilitychange", handleVisibilityChange)
         return () =>
-            window.removeEventListener("beforeunload", handleBeforeUnload)
-    }, [sessionId])
+            document.removeEventListener(
+                "visibilitychange",
+                handleVisibilityChange,
+            )
+    }, [sessionManager, buildSessionData])
 
     const onFormSubmit = async (e: React.FormEvent<HTMLFormElement>) => {
         e.preventDefault()
@@ -627,7 +772,6 @@ export default function ChatPanel({
                 // Save XML snapshot for this message (will be at index = current messages.length)
                 const messageIndex = messages.length
                 xmlSnapshotsRef.current.set(messageIndex, chartXml)
-                saveXmlSnapshots()
 
                 sendChatMessage(parts, chartXml, previousXml, sessionId)
 
@@ -641,30 +785,97 @@ export default function ChatPanel({
         }
     }
 
-    const handleNewChat = useCallback(() => {
+    // Handle session switching from history dropdown
+    const handleSelectSession = useCallback(
+        async (sessionId: string) => {
+            if (!sessionManager.isAvailable) return
+
+            // Save current session before switching
+            if (messages.length > 0) {
+                const sessionData = await buildSessionData({
+                    withThumbnail: true,
+                })
+                await sessionManager.saveCurrentSession(sessionData)
+            }
+
+            // Switch to selected session
+            const sessionData = await sessionManager.switchSession(sessionId)
+            if (sessionData) {
+                const hasRealDiagram = isRealDiagram(sessionData.diagramXml)
+                justLoadedSessionRef.current = true
+
+                // CRITICAL: Update latestSvgRef with the NEW session's thumbnail
+                // This prevents stale thumbnail from previous session being used by auto-save
+                latestSvgRef.current = sessionData.thumbnailDataUrl || ""
+
+                // Track if this session has no real diagram - to prevent thumbnail contamination
+                if (!hasRealDiagram) {
+                    justLoadedSessionIdRef.current = sessionId
+                } else {
+                    justLoadedSessionIdRef.current = null
+                }
+                syncUIWithSession(sessionData)
+                router.replace(`?session=${sessionId}`, { scroll: false })
+            }
+        },
+        [sessionManager, messages, buildSessionData, syncUIWithSession, router],
+    )
+
+    // Handle session deletion from history dropdown
+    const handleDeleteSession = useCallback(
+        async (sessionId: string) => {
+            if (!sessionManager.isAvailable) return
+            const result = await sessionManager.deleteSession(sessionId)
+
+            if (result.wasCurrentSession) {
+                // Deleted current session - clear UI and URL
+                syncUIWithSession(null)
+                router.replace(window.location.pathname, { scroll: false })
+            }
+        },
+        [sessionManager, syncUIWithSession, router],
+    )
+
+    const handleNewChat = useCallback(async () => {
+        // Save current session before creating new one
+        if (sessionManager.isAvailable && messages.length > 0) {
+            const sessionData = await buildSessionData({ withThumbnail: true })
+            await sessionManager.saveCurrentSession(sessionData)
+            // Refresh sessions list to ensure dropdown shows the saved session
+            await sessionManager.refreshSessions()
+        }
+
+        // Clear session manager state BEFORE clearing URL to prevent race condition
+        // (otherwise the URL update effect would restore the old session URL)
+        sessionManager.clearCurrentSession()
+
+        // Clear UI state (can't use syncUIWithSession here because we also need to clear files)
         setMessages([])
         clearDiagram()
+        setDiagramHistory([])
         handleFileChange([]) // Use handleFileChange to also clear pdfData
         const newSessionId = `session-${Date.now()}-${Math.random()
             .toString(36)
             .slice(2, 9)}`
         setSessionId(newSessionId)
         xmlSnapshotsRef.current.clear()
-        // Clear localStorage with error handling
-        try {
-            localStorage.removeItem(STORAGE_MESSAGES_KEY)
-            localStorage.removeItem(STORAGE_XML_SNAPSHOTS_KEY)
-            localStorage.removeItem(STORAGE_DIAGRAM_XML_KEY)
-            localStorage.setItem(STORAGE_SESSION_ID_KEY, newSessionId)
         sessionStorage.removeItem(SESSION_STORAGE_INPUT_KEY)
         toast.success(dict.dialogs.clearSuccess)
-        } catch (error) {
-            console.error("Failed to clear localStorage:", error)
-            toast.warning(dict.errors.storageUpdateFailed)
-        }
 
-        setShowNewChatDialog(false)
-    }, [clearDiagram, handleFileChange, setMessages, setSessionId])
+        // Clear URL param to show blank state
+        router.replace(window.location.pathname, { scroll: false })
+    }, [
+        clearDiagram,
+        handleFileChange,
+        setMessages,
+        setSessionId,
+        sessionManager,
+        messages,
+        router,
+        dict.dialogs.clearSuccess,
+        buildSessionData,
+        setDiagramHistory,
+    ])
 
     const handleInputChange = (
         e: React.ChangeEvent<HTMLInputElement | HTMLTextAreaElement>,
@@ -701,7 +912,6 @@ export default function ChatPanel({
                 xmlSnapshotsRef.current.delete(key)
             }
         }
-        saveXmlSnapshots()
     }
 
     // Send chat message with headers
@@ -915,12 +1125,16 @@ export default function ChatPanel({
 
     // Full view
     return (
-        <div className="h-full flex flex-col bg-card shadow-soft animate-slide-in-right rounded-xl border border-border/30 relative">
+        <div
+            className={cn(
+                "h-full flex flex-col bg-card shadow-soft rounded-xl border border-border/30 relative",
+                shouldAnimatePanel && "animate-slide-in-right",
+            )}
+        >
             <Toaster
-                position="bottom-center"
+                position="bottom-left"
                 richColors
                 expand
-                style={{ position: "absolute" }}
                 toastOptions={{
                     style: {
                         maxWidth: "480px",
@@ -933,7 +1147,15 @@ export default function ChatPanel({
                 className={`${isMobile ? "px-3 py-2" : "px-5 py-4"} border-b border-border/50`}
             >
                 <div className="flex items-center justify-between">
-                    <div className="flex items-center gap-2 overflow-x-hidden">
+                    <button
+                        type="button"
+                        onClick={handleNewChat}
+                        disabled={
+                            status === "streaming" || status === "submitted"
+                        }
+                        className="flex items-center gap-2 overflow-x-hidden hover:opacity-80 transition-opacity cursor-pointer disabled:opacity-50 disabled:cursor-not-allowed"
+                        title={dict.nav.newChat}
+                    >
                         <div className="flex items-center gap-2">
                             <Image
                                 src={
@@ -952,14 +1174,17 @@ export default function ChatPanel({
                                 Next AI Drawio
                             </h1>
                         </div>
-                    </div>
+                    </button>
                     <div className="flex items-center gap-1 justify-end overflow-visible">
                         <ButtonWithTooltip
                             tooltipContent={dict.nav.newChat}
                             variant="ghost"
                             size="icon"
-                            onClick={() => setShowNewChatDialog(true)}
-                            className="hover:bg-accent"
+                            onClick={handleNewChat}
+                            disabled={
+                                status === "streaming" || status === "submitted"
+                            }
+                            className="hover:bg-accent disabled:opacity-50 disabled:cursor-not-allowed"
                         >
                             <MessageSquarePlus
                                 className={`${isMobile ? "h-4 w-4" : "h-5 w-5"} text-muted-foreground`}
@@ -1006,6 +1231,11 @@ export default function ChatPanel({
                     onRegenerate={handleRegenerate}
                     status={status}
                     onEditMessage={handleEditMessage}
+                    isRestored={isRestored}
+                    sessions={sessionManager.sessions}
+                    onSelectSession={handleSelectSession}
+                    onDeleteSession={handleDeleteSession}
+                    loadedMessageIdsRef={loadedMessageIdsRef}
                 />
             </main>
 
@@ -1029,7 +1259,6 @@ export default function ChatPanel({
                     status={status}
                     onSubmit={onFormSubmit}
                     onChange={handleInputChange}
-                    onClearChat={handleNewChat}
                     files={files}
                     onFileChange={handleFileChange}
                     pdfData={pdfData}
@@ -1060,12 +1289,6 @@ export default function ChatPanel({
                 onOpenChange={setShowModelConfigDialog}
                 modelConfig={modelConfig}
             />
-
-            <ResetWarningModal
-                open={showNewChatDialog}
-                onOpenChange={setShowNewChatDialog}
-                onClear={handleNewChat}
-            />
         </div>
     )
 }

components/chat/ChatLobby.tsx

@@ -0,0 +1,274 @@
+"use client"
+
+import {
+    ChevronDown,
+    ChevronUp,
+    MessageSquare,
+    Search,
+    Trash2,
+    X,
+} from "lucide-react"
+import Image from "next/image"
+import { useState } from "react"
+import ExamplePanel from "@/components/chat-example-panel"
+import {
+    AlertDialog,
+    AlertDialogAction,
+    AlertDialogCancel,
+    AlertDialogContent,
+    AlertDialogDescription,
+    AlertDialogFooter,
+    AlertDialogHeader,
+    AlertDialogTitle,
+} from "@/components/ui/alert-dialog"
+
+interface SessionMetadata {
+    id: string
+    title: string
+    updatedAt: number
+    thumbnailDataUrl?: string
+}
+
+interface ChatLobbyProps {
+    sessions: SessionMetadata[]
+    onSelectSession: (id: string) => void
+    onDeleteSession?: (id: string) => void
+    setInput: (input: string) => void
+    setFiles: (files: File[]) => void
+    dict: {
+        sessionHistory?: {
+            recentChats?: string
+            searchPlaceholder?: string
+            noResults?: string
+            justNow?: string
+            deleteTitle?: string
+            deleteDescription?: string
+        }
+        examples?: {
+            quickExamples?: string
+        }
+        common: {
+            delete: string
+            cancel: string
+        }
+    }
+}
+
+// Helper to format session date
+function formatSessionDate(
+    timestamp: number,
+    dict?: { justNow?: string },
+): string {
+    const date = new Date(timestamp)
+    const now = new Date()
+    const diffMs = now.getTime() - date.getTime()
+    const diffMins = Math.floor(diffMs / (1000 * 60))
+    const diffHours = Math.floor(diffMs / (1000 * 60 * 60))
+
+    if (diffMins < 1) return dict?.justNow || "Just now"
+    if (diffMins < 60) return `${diffMins}m ago`
+    if (diffHours < 24) return `${diffHours}h ago`
+
+    return date.toLocaleDateString(undefined, {
+        month: "short",
+        day: "numeric",
+    })
+}
+
+export function ChatLobby({
+    sessions,
+    onSelectSession,
+    onDeleteSession,
+    setInput,
+    setFiles,
+    dict,
+}: ChatLobbyProps) {
+    // Track whether examples section is expanded (collapsed by default when there's history)
+    const [examplesExpanded, setExamplesExpanded] = useState(false)
+    // Delete confirmation dialog state
+    const [deleteDialogOpen, setDeleteDialogOpen] = useState(false)
+    const [sessionToDelete, setSessionToDelete] = useState<string | null>(null)
+    // Search filter for history
+    const [searchQuery, setSearchQuery] = useState("")
+
+    const hasHistory = sessions.length > 0
+
+    if (!hasHistory) {
+        // Show full examples when no history
+        return <ExamplePanel setInput={setInput} setFiles={setFiles} />
+    }
+
+    // Show history + collapsible examples when there are sessions
+    return (
+        <div className="py-6 px-2 animate-fade-in">
+            {/* Recent Chats Section */}
+            <div className="mb-6">
+                <p className="text-xs font-medium text-muted-foreground uppercase tracking-wider px-1 mb-3">
+                    {dict.sessionHistory?.recentChats || "Recent Chats"}
+                </p>
+                {/* Search Bar */}
+                <div className="relative mb-3">
+                    <Search className="absolute left-3 top-1/2 -translate-y-1/2 w-4 h-4 text-muted-foreground" />
+                    <input
+                        type="text"
+                        placeholder={
+                            dict.sessionHistory?.searchPlaceholder ||
+                            "Search chats..."
+                        }
+                        value={searchQuery}
+                        onChange={(e) => setSearchQuery(e.target.value)}
+                        className="w-full pl-9 pr-3 py-2 text-sm rounded-lg border border-border/60 bg-background focus:outline-none focus:ring-2 focus:ring-primary/30 focus:border-primary/50 transition-all"
+                    />
+                    {searchQuery && (
+                        <button
+                            type="button"
+                            onClick={() => setSearchQuery("")}
+                            className="absolute right-2 top-1/2 -translate-y-1/2 p-1 rounded hover:bg-muted transition-colors"
+                        >
+                            <X className="w-3 h-3 text-muted-foreground" />
+                        </button>
+                    )}
+                </div>
+                <div className="space-y-2">
+                    {sessions
+                        .filter((session) =>
+                            session.title
+                                .toLowerCase()
+                                .includes(searchQuery.toLowerCase()),
+                        )
+                        .map((session) => (
+                            // biome-ignore lint/a11y/useSemanticElements: Cannot use button - has nested delete button which causes hydration error
+                            <div
+                                key={session.id}
+                                role="button"
+                                tabIndex={0}
+                                className="group w-full flex items-center gap-3 p-3 rounded-xl border border-border/60 bg-card hover:bg-accent/50 hover:border-primary/30 transition-all duration-200 cursor-pointer text-left"
+                                onClick={() => onSelectSession(session.id)}
+                                onKeyDown={(e) => {
+                                    if (e.key === "Enter" || e.key === " ") {
+                                        e.preventDefault()
+                                        onSelectSession(session.id)
+                                    }
+                                }}
+                            >
+                                {session.thumbnailDataUrl ? (
+                                    <div className="w-12 h-12 shrink-0 rounded-lg border bg-white overflow-hidden">
+                                        <Image
+                                            src={session.thumbnailDataUrl}
+                                            alt=""
+                                            width={48}
+                                            height={48}
+                                            className="object-contain w-full h-full"
+                                        />
+                                    </div>
+                                ) : (
+                                    <div className="w-12 h-12 shrink-0 rounded-lg bg-primary/10 flex items-center justify-center">
+                                        <MessageSquare className="w-5 h-5 text-primary" />
+                                    </div>
+                                )}
+                                <div className="min-w-0 flex-1">
+                                    <div className="text-sm font-medium truncate">
+                                        {session.title}
+                                    </div>
+                                    <div className="text-xs text-muted-foreground">
+                                        {formatSessionDate(
+                                            session.updatedAt,
+                                            dict.sessionHistory,
+                                        )}
+                                    </div>
+                                </div>
+                                {onDeleteSession && (
+                                    <button
+                                        type="button"
+                                        onClick={(e) => {
+                                            e.stopPropagation()
+                                            setSessionToDelete(session.id)
+                                            setDeleteDialogOpen(true)
+                                        }}
+                                        className="p-1.5 rounded-lg opacity-0 group-hover:opacity-100 text-muted-foreground hover:text-destructive hover:bg-destructive/10 transition-all"
+                                        title={dict.common.delete}
+                                    >
+                                        <Trash2 className="w-4 h-4" />
+                                    </button>
+                                )}
+                            </div>
+                        ))}
+                    {sessions.filter((s) =>
+                        s.title
+                            .toLowerCase()
+                            .includes(searchQuery.toLowerCase()),
+                    ).length === 0 &&
+                        searchQuery && (
+                            <p className="text-sm text-muted-foreground text-center py-4">
+                                {dict.sessionHistory?.noResults ||
+                                    "No chats found"}
+                            </p>
+                        )}
+                </div>
+            </div>
+
+            {/* Collapsible Examples Section */}
+            <div className="border-t border-border/50 pt-4">
+                <button
+                    type="button"
+                    onClick={() => setExamplesExpanded(!examplesExpanded)}
+                    className="w-full flex items-center justify-between px-1 py-2 text-xs font-medium text-muted-foreground uppercase tracking-wider hover:text-foreground transition-colors"
+                >
+                    <span>
+                        {dict.examples?.quickExamples || "Quick Examples"}
+                    </span>
+                    {examplesExpanded ? (
+                        <ChevronUp className="w-4 h-4" />
+                    ) : (
+                        <ChevronDown className="w-4 h-4" />
+                    )}
+                </button>
+                {examplesExpanded && (
+                    <div className="mt-2">
+                        <ExamplePanel
+                            setInput={setInput}
+                            setFiles={setFiles}
+                            minimal
+                        />
+                    </div>
+                )}
+            </div>
+
+            {/* Delete Confirmation Dialog */}
+            <AlertDialog
+                open={deleteDialogOpen}
+                onOpenChange={setDeleteDialogOpen}
+            >
+                <AlertDialogContent className="max-w-sm">
+                    <AlertDialogHeader>
+                        <AlertDialogTitle>
+                            {dict.sessionHistory?.deleteTitle ||
+                                "Delete this chat?"}
+                        </AlertDialogTitle>
+                        <AlertDialogDescription>
+                            {dict.sessionHistory?.deleteDescription ||
+                                "This will permanently delete this chat session and its diagram. This action cannot be undone."}
+                        </AlertDialogDescription>
+                    </AlertDialogHeader>
+                    <AlertDialogFooter>
+                        <AlertDialogCancel>
+                            {dict.common.cancel}
+                        </AlertDialogCancel>
+                        <AlertDialogAction
+                            onClick={() => {
+                                if (sessionToDelete && onDeleteSession) {
+                                    onDeleteSession(sessionToDelete)
+                                }
+                                setDeleteDialogOpen(false)
+                                setSessionToDelete(null)
+                            }}
+                            className="border border-red-300 bg-red-50 text-red-700 hover:bg-red-100 hover:border-red-400"
+                        >
+                            {dict.common.delete}
+                        </AlertDialogAction>
+                    </AlertDialogFooter>
+                </AlertDialogContent>
+            </AlertDialog>
+        </div>
+    )
+}

components/chat/ToolCallCard.tsx

@@ -0,0 +1,250 @@
+"use client"
+
+import { Check, ChevronDown, ChevronUp, Copy, Cpu } from "lucide-react"
+import type { Dispatch, SetStateAction } from "react"
+import { CodeBlock } from "@/components/code-block"
+import { isMxCellXmlComplete } from "@/lib/utils"
+import type { DiagramOperation, ToolPartLike } from "./types"
+
+interface ToolCallCardProps {
+    part: ToolPartLike
+    expandedTools: Record<string, boolean>
+    setExpandedTools: Dispatch<SetStateAction<Record<string, boolean>>>
+    onCopy: (callId: string, text: string, isToolCall: boolean) => void
+    copiedToolCallId: string | null
+    copyFailedToolCallId: string | null
+    dict: {
+        tools: { complete: string }
+        chat: { copied: string; failedToCopy: string; copyResponse: string }
+    }
+}
+
+function OperationsDisplay({ operations }: { operations: DiagramOperation[] }) {
+    return (
+        <div className="space-y-3">
+            {operations.map((op, index) => (
+                <div
+                    key={`${op.operation}-${op.cell_id}-${index}`}
+                    className="rounded-lg border border-border/50 overflow-hidden bg-background/50"
+                >
+                    <div className="px-3 py-1.5 bg-muted/40 border-b border-border/30 flex items-center gap-2">
+                        <span
+                            className={`text-[10px] font-medium uppercase tracking-wide ${
+                                op.operation === "delete"
+                                    ? "text-red-600"
+                                    : op.operation === "add"
+                                      ? "text-green-600"
+                                      : "text-blue-600"
+                            }`}
+                        >
+                            {op.operation}
+                        </span>
+                        <span className="text-xs text-muted-foreground">
+                            cell_id: {op.cell_id}
+                        </span>
+                    </div>
+                    {op.new_xml && (
+                        <div className="px-3 py-2">
+                            <pre className="text-[11px] font-mono text-foreground/80 bg-muted/30 rounded px-2 py-1.5 overflow-x-auto whitespace-pre-wrap break-all">
+                                {op.new_xml}
+                            </pre>
+                        </div>
+                    )}
+                </div>
+            ))}
+        </div>
+    )
+}
+
+export function ToolCallCard({
+    part,
+    expandedTools,
+    setExpandedTools,
+    onCopy,
+    copiedToolCallId,
+    copyFailedToolCallId,
+    dict,
+}: ToolCallCardProps) {
+    const callId = part.toolCallId
+    const { state, input, output } = part
+    // Default to collapsed if tool is complete, expanded if still streaming
+    const isExpanded = expandedTools[callId] ?? state !== "output-available"
+    const toolName = part.type?.replace("tool-", "")
+    const isCopied = copiedToolCallId === callId
+
+    const toggleExpanded = () => {
+        setExpandedTools((prev) => ({
+            ...prev,
+            [callId]: !isExpanded,
+        }))
+    }
+
+    const getToolDisplayName = (name: string) => {
+        switch (name) {
+            case "display_diagram":
+                return "Generate Diagram"
+            case "edit_diagram":
+                return "Edit Diagram"
+            case "get_shape_library":
+                return "Get Shape Library"
+            default:
+                return name
+        }
+    }
+
+    const handleCopy = () => {
+        let textToCopy = ""
+
+        if (input && typeof input === "object") {
+            if (input.xml) {
+                textToCopy = input.xml
+            } else if (input.operations && Array.isArray(input.operations)) {
+                textToCopy = JSON.stringify(input.operations, null, 2)
+            } else if (Object.keys(input).length > 0) {
+                textToCopy = JSON.stringify(input, null, 2)
+            }
+        }
+
+        if (
+            output &&
+            toolName === "get_shape_library" &&
+            typeof output === "string"
+        ) {
+            textToCopy = output
+        }
+
+        if (textToCopy) {
+            onCopy(callId, textToCopy, true)
+        }
+    }
+
+    return (
+        <div className="my-3 rounded-xl border border-border/60 bg-muted/30 overflow-hidden">
+            <div className="flex items-center justify-between px-4 py-3 bg-muted/50">
+                <div className="flex items-center gap-2">
+                    <div className="w-6 h-6 rounded-md bg-primary/10 flex items-center justify-center">
+                        <Cpu className="w-3.5 h-3.5 text-primary" />
+                    </div>
+                    <span className="text-sm font-medium text-foreground/80">
+                        {getToolDisplayName(toolName)}
+                    </span>
+                </div>
+                <div className="flex items-center gap-2">
+                    {state === "input-streaming" && (
+                        <div className="h-4 w-4 border-2 border-primary border-t-transparent rounded-full animate-spin" />
+                    )}
+                    {state === "output-available" && (
+                        <>
+                            <span className="text-xs font-medium text-green-600 bg-green-50 px-2 py-0.5 rounded-full">
+                                {dict.tools.complete}
+                            </span>
+                            {isExpanded && (
+                                <button
+                                    type="button"
+                                    onClick={handleCopy}
+                                    className="p-1 rounded hover:bg-muted transition-colors"
+                                    title={
+                                        copiedToolCallId === callId
+                                            ? dict.chat.copied
+                                            : copyFailedToolCallId === callId
+                                              ? dict.chat.failedToCopy
+                                              : dict.chat.copyResponse
+                                    }
+                                >
+                                    {isCopied ? (
+                                        <Check className="w-4 h-4 text-green-600" />
+                                    ) : (
+                                        <Copy className="w-4 h-4 text-muted-foreground" />
+                                    )}
+                                </button>
+                            )}
+                        </>
+                    )}
+                    {state === "output-error" &&
+                        (() => {
+                            // Check if this is a truncation (incomplete XML) vs real error
+                            const isTruncated =
+                                (toolName === "display_diagram" ||
+                                    toolName === "append_diagram") &&
+                                !isMxCellXmlComplete(input?.xml)
+                            return isTruncated ? (
+                                <span className="text-xs font-medium text-yellow-600 bg-yellow-50 px-2 py-0.5 rounded-full">
+                                    Truncated
+                                </span>
+                            ) : (
+                                <span className="text-xs font-medium text-red-600 bg-red-50 px-2 py-0.5 rounded-full">
+                                    Error
+                                </span>
+                            )
+                        })()}
+                    {input && Object.keys(input).length > 0 && (
+                        <button
+                            type="button"
+                            onClick={toggleExpanded}
+                            className="p-1 rounded hover:bg-muted transition-colors"
+                        >
+                            {isExpanded ? (
+                                <ChevronUp className="w-4 h-4 text-muted-foreground" />
+                            ) : (
+                                <ChevronDown className="w-4 h-4 text-muted-foreground" />
+                            )}
+                        </button>
+                    )}
+                </div>
+            </div>
+            {input && isExpanded && (
+                <div className="px-4 py-3 border-t border-border/40 bg-muted/20">
+                    {typeof input === "object" && input.xml ? (
+                        <CodeBlock code={input.xml} language="xml" />
+                    ) : typeof input === "object" &&
+                      input.operations &&
+                      Array.isArray(input.operations) ? (
+                        <OperationsDisplay operations={input.operations} />
+                    ) : typeof input === "object" &&
+                      Object.keys(input).length > 0 ? (
+                        <CodeBlock
+                            code={JSON.stringify(input, null, 2)}
+                            language="json"
+                        />
+                    ) : null}
+                </div>
+            )}
+            {output &&
+                state === "output-error" &&
+                (() => {
+                    const isTruncated =
+                        (toolName === "display_diagram" ||
+                            toolName === "append_diagram") &&
+                        !isMxCellXmlComplete(input?.xml)
+                    return (
+                        <div
+                            className={`px-4 py-3 border-t border-border/40 text-sm ${isTruncated ? "text-yellow-600" : "text-red-600"}`}
+                        >
+                            {isTruncated
+                                ? "Output truncated due to length limits. Try a simpler request or increase the maxOutputLength."
+                                : output}
+                        </div>
+                    )
+                })()}
+            {/* Show get_shape_library output on success */}
+            {output &&
+                toolName === "get_shape_library" &&
+                state === "output-available" &&
+                isExpanded && (
+                    <div className="px-4 py-3 border-t border-border/40">
+                        <div className="text-xs text-muted-foreground mb-2">
+                            Library loaded (
+                            {typeof output === "string" ? output.length : 0}{" "}
+                            chars)
+                        </div>
+                        <pre className="text-xs bg-muted/50 p-2 rounded-md overflow-auto max-h-32 whitespace-pre-wrap">
+                            {typeof output === "string"
+                                ? output.substring(0, 800) +
+                                  (output.length > 800 ? "\n..." : "")
+                                : String(output)}
+                        </pre>
+                    </div>
+                )}
+        </div>
+    )
+}

components/chat/types.ts

@@ -0,0 +1,16 @@
+export interface DiagramOperation {
+    operation: "update" | "add" | "delete"
+    cell_id: string
+    new_xml?: string
+}
+
+export interface ToolPartLike {
+    type: string
+    toolCallId: string
+    state?: string
+    input?: {
+        xml?: string
+        operations?: DiagramOperation[]
+    } & Record<string, unknown>
+    output?: string
+}

contexts/diagram-context.tsx

@@ -3,15 +3,20 @@
 import type React from "react"
 import { createContext, useContext, useEffect, useRef, useState } from "react"
 import type { DrawIoEmbedRef } from "react-drawio"
-import { STORAGE_DIAGRAM_XML_KEY } from "@/components/chat-panel"
+import { toast } from "sonner"
 import type { ExportFormat } from "@/components/save-dialog"
 import { getApiEndpoint } from "@/lib/base-path"
-import { extractDiagramXML, validateAndFixXml } from "../lib/utils"
+import {
+    extractDiagramXML,
+    isRealDiagram,
+    validateAndFixXml,
+} from "../lib/utils"
 
 interface DiagramContextType {
     chartXML: string
     latestSvg: string
     diagramHistory: { svg: string; xml: string }[]
+    setDiagramHistory: (history: { svg: string; xml: string }[]) => void
     loadDiagram: (chart: string, skipValidation?: boolean) => string | null
     handleExport: () => void
     handleExportWithoutHistory: () => void
@@ -23,8 +28,9 @@ interface DiagramContextType {
         filename: string,
         format: ExportFormat,
         sessionId?: string,
+        successMessage?: string,
     ) => void
-    saveDiagramToStorage: () => Promise<void>
+    getThumbnailSvg: () => Promise<string | null>
     isDrawioReady: boolean
     onDrawioLoad: () => void
     resetDrawioReady: () => void
@@ -41,72 +47,52 @@ export function DiagramProvider({ children }: { children: React.ReactNode }) {
         { svg: string; xml: string }[]
     >([])
     const [isDrawioReady, setIsDrawioReady] = useState(false)
-    const [canSaveDiagram, setCanSaveDiagram] = useState(false)
     const [showSaveDialog, setShowSaveDialog] = useState(false)
     const hasCalledOnLoadRef = useRef(false)
     const drawioRef = useRef<DrawIoEmbedRef | null>(null)
     const resolverRef = useRef<((value: string) => void) | null>(null)
     // Track if we're expecting an export for history (user-initiated)
     const expectHistoryExportRef = useRef<boolean>(false)
-    // Track if diagram has been restored from localStorage
+    // Track if diagram has been restored after DrawIO remount (e.g., theme change)
     const hasDiagramRestoredRef = useRef<boolean>(false)
+    // Track latest chartXML for restoration after remount
+    const chartXMLRef = useRef<string>("")
 
     const onDrawioLoad = () => {
         // Only set ready state once to prevent infinite loops
         if (hasCalledOnLoadRef.current) return
         hasCalledOnLoadRef.current = true
-        // console.log("[DiagramContext] DrawIO loaded, setting ready state")
         setIsDrawioReady(true)
     }
 
     const resetDrawioReady = () => {
-        // console.log("[DiagramContext] Resetting DrawIO ready state")
         hasCalledOnLoadRef.current = false
         setIsDrawioReady(false)
     }
 
-    // Restore diagram XML when DrawIO becomes ready
-    // eslint-disable-next-line react-hooks/exhaustive-deps -- loadDiagram uses refs internally and is stable
+    // Keep chartXMLRef in sync with state for restoration after remount
     useEffect(() => {
-        // Reset restore flag when DrawIO is not ready (e.g., theme/UI change remounts it)
+        chartXMLRef.current = chartXML
+    }, [chartXML])
+
+    // Restore diagram when DrawIO becomes ready after remount (e.g., theme/UI change)
+    useEffect(() => {
+        // Reset restore flag when DrawIO is not ready (preparing for next restore cycle)
         if (!isDrawioReady) {
             hasDiagramRestoredRef.current = false
-            setCanSaveDiagram(false)
             return
         }
+        // Only restore once per ready cycle
         if (hasDiagramRestoredRef.current) return
         hasDiagramRestoredRef.current = true
 
-        try {
-            const savedDiagramXml = localStorage.getItem(
-                STORAGE_DIAGRAM_XML_KEY,
-            )
-            if (savedDiagramXml) {
-                // Skip validation for trusted saved diagrams
-                loadDiagram(savedDiagramXml, true)
+        // Restore diagram from ref if we have one
+        const xmlToRestore = chartXMLRef.current
+        if (isRealDiagram(xmlToRestore) && drawioRef.current) {
+            drawioRef.current.load({ xml: xmlToRestore })
         }
-        } catch (error) {
-            console.error("Failed to restore diagram from localStorage:", error)
-        }
-
-        // Allow saving after restore is complete
-        setTimeout(() => {
-            setCanSaveDiagram(true)
-        }, 500)
     }, [isDrawioReady])
 
-    // Save diagram XML to localStorage whenever it changes (debounced)
-    useEffect(() => {
-        if (!canSaveDiagram) return
-        if (!chartXML || chartXML.length <= 300) return
-
-        const timeoutId = setTimeout(() => {
-            localStorage.setItem(STORAGE_DIAGRAM_XML_KEY, chartXML)
-        }, 1000)
-
-        return () => clearTimeout(timeoutId)
-    }, [chartXML, canSaveDiagram])
-
     // Track if we're expecting an export for file save (stores raw export data)
     const saveResolverRef = useRef<{
         resolver: ((data: string) => void) | null
@@ -132,27 +118,32 @@ export function DiagramProvider({ children }: { children: React.ReactNode }) {
         }
     }
 
-    // Save current diagram to localStorage (used before theme/UI changes)
-    const saveDiagramToStorage = async (): Promise<void> => {
-        if (!drawioRef.current) return
+    // Get current diagram as SVG for thumbnail (used by session storage)
+    const getThumbnailSvg = async (): Promise<string | null> => {
+        if (!drawioRef.current) return null
+        // Don't export if diagram is empty
+        if (!isRealDiagram(chartXML)) return null
 
         try {
-            const currentXml = await Promise.race([
+            const svgData = await Promise.race([
                 new Promise<string>((resolve) => {
                     resolverRef.current = resolve
                     drawioRef.current?.exportDiagram({ format: "xmlsvg" })
                 }),
                 new Promise<string>((_, reject) =>
-                    setTimeout(() => reject(new Error("Export timeout")), 2000),
+                    setTimeout(() => reject(new Error("Export timeout")), 3000),
                 ),
             ])
 
-            // Only save if diagram has meaningful content (not empty template)
-            if (currentXml && currentXml.length > 300) {
-                localStorage.setItem(STORAGE_DIAGRAM_XML_KEY, currentXml)
+            // Update latestSvg so it's available for future saves
+            if (svgData?.includes("<svg")) {
+                setLatestSvg(svgData)
+                return svgData
             }
-        } catch (error) {
-            console.error("Failed to save diagram to storage:", error)
+            return null
+        } catch {
+            // Timeout is expected occasionally - don't log as error
+            return null
         }
     }
 
@@ -247,6 +238,7 @@ export function DiagramProvider({ children }: { children: React.ReactNode }) {
         filename: string,
         format: ExportFormat,
         sessionId?: string,
+        successMessage?: string,
     ) => {
         if (!drawioRef.current) {
             console.warn("Draw.io editor not ready")
@@ -273,9 +265,6 @@ export function DiagramProvider({ children }: { children: React.ReactNode }) {
                     fileContent = xmlContent
                     mimeType = "application/xml"
                     extension = ".drawio"
-
-                    // Save to localStorage when user manually saves
-                    localStorage.setItem(STORAGE_DIAGRAM_XML_KEY, xmlContent)
                 } else if (format === "png") {
                     // PNG data comes as base64 data URL
                     fileContent = exportData
@@ -311,6 +300,14 @@ export function DiagramProvider({ children }: { children: React.ReactNode }) {
                 a.click()
                 document.body.removeChild(a)
 
+                // Show success toast after download is initiated
+                if (successMessage) {
+                    toast.success(successMessage, {
+                        position: "bottom-left",
+                        duration: 2500,
+                    })
+                }
+
                 // Delay URL revocation to ensure download completes
                 if (!url.startsWith("data:")) {
                     setTimeout(() => URL.revokeObjectURL(url), 100)
@@ -346,6 +343,7 @@ export function DiagramProvider({ children }: { children: React.ReactNode }) {
                 chartXML,
                 latestSvg,
                 diagramHistory,
+                setDiagramHistory,
                 loadDiagram,
                 handleExport,
                 handleExportWithoutHistory,
@@ -354,7 +352,7 @@ export function DiagramProvider({ children }: { children: React.ReactNode }) {
                 handleDiagramExport,
                 clearDiagram,
                 saveDiagramToFile,
-                saveDiagramToStorage,
+                getThumbnailSvg,
                 isDrawioReady,
                 onDrawioLoad,
                 resetDrawioReady,

docker-compose.yml

@@ -11,7 +11,7 @@ services:
         # - NEXT_PUBLIC_BASE_PATH=/nextaidrawio
     ports: ["3000:3000"]
     env_file: .env
-    environment:
-      # For subdirectory deployment, uncomment and set your path:
+    # environment:
+    #   # For subdirectory deployment, uncomment and set your path:
     #   NEXT_PUBLIC_BASE_PATH: /nextaidrawio
     depends_on: [drawio]

hooks/use-session-manager.ts

@@ -0,0 +1,322 @@
+"use client"
+
+import { useCallback, useEffect, useRef, useState } from "react"
+import {
+    type ChatSession,
+    createEmptySession,
+    deleteSession as deleteSessionFromDB,
+    enforceSessionLimit,
+    extractTitle,
+    getAllSessionMetadata,
+    getSession,
+    isIndexedDBAvailable,
+    migrateFromLocalStorage,
+    type SessionMetadata,
+    type StoredMessage,
+    saveSession,
+} from "@/lib/session-storage"
+
+export interface SessionData {
+    messages: StoredMessage[]
+    xmlSnapshots: [number, string][]
+    diagramXml: string
+    thumbnailDataUrl?: string
+    diagramHistory?: { svg: string; xml: string }[]
+}
+
+export interface UseSessionManagerReturn {
+    // State
+    sessions: SessionMetadata[]
+    currentSessionId: string | null
+    currentSession: ChatSession | null
+    isLoading: boolean
+    isAvailable: boolean
+
+    // Actions
+    switchSession: (id: string) => Promise<SessionData | null>
+    deleteSession: (id: string) => Promise<{ wasCurrentSession: boolean }>
+    // forSessionId: optional session ID to verify save targets correct session (prevents stale debounce writes)
+    saveCurrentSession: (
+        data: SessionData,
+        forSessionId?: string | null,
+    ) => Promise<void>
+    refreshSessions: () => Promise<void>
+    clearCurrentSession: () => void
+}
+
+interface UseSessionManagerOptions {
+    /** Session ID from URL param - if provided, load this session; if null, start blank */
+    initialSessionId?: string | null
+}
+
+export function useSessionManager(
+    options: UseSessionManagerOptions = {},
+): UseSessionManagerReturn {
+    const { initialSessionId } = options
+    const [sessions, setSessions] = useState<SessionMetadata[]>([])
+    const [currentSessionId, setCurrentSessionId] = useState<string | null>(
+        null,
+    )
+    const [currentSession, setCurrentSession] = useState<ChatSession | null>(
+        null,
+    )
+    const [isLoading, setIsLoading] = useState(true)
+    const [isAvailable, setIsAvailable] = useState(false)
+
+    const isInitializedRef = useRef(false)
+    // Sequence guard for URL changes - prevents out-of-order async resolution
+    const urlChangeSequenceRef = useRef(0)
+
+    // Load sessions list
+    const refreshSessions = useCallback(async () => {
+        if (!isIndexedDBAvailable()) return
+        try {
+            const metadata = await getAllSessionMetadata()
+            setSessions(metadata)
+        } catch (error) {
+            console.error("Failed to refresh sessions:", error)
+        }
+    }, [])
+
+    // Initialize on mount
+    useEffect(() => {
+        if (isInitializedRef.current) return
+        isInitializedRef.current = true
+
+        async function init() {
+            setIsLoading(true)
+
+            if (!isIndexedDBAvailable()) {
+                setIsAvailable(false)
+                setIsLoading(false)
+                return
+            }
+
+            setIsAvailable(true)
+
+            try {
+                // Run migration first (one-time conversion from localStorage)
+                await migrateFromLocalStorage()
+
+                // Load sessions list
+                const metadata = await getAllSessionMetadata()
+                setSessions(metadata)
+
+                // Only load a session if initialSessionId is provided (from URL param)
+                if (initialSessionId) {
+                    const session = await getSession(initialSessionId)
+                    if (session) {
+                        setCurrentSession(session)
+                        setCurrentSessionId(session.id)
+                    }
+                    // If session not found, stay in blank state (URL has invalid session ID)
+                }
+                // If no initialSessionId, start with blank state (no auto-restore)
+            } catch (error) {
+                console.error("Failed to initialize session manager:", error)
+            } finally {
+                setIsLoading(false)
+            }
+        }
+
+        init()
+    }, [initialSessionId])
+
+    // Handle URL session ID changes after initialization
+    // Note: intentionally NOT including currentSessionId in deps to avoid race conditions
+    // when clearCurrentSession() is called before URL updates
+    useEffect(() => {
+        if (!isInitializedRef.current) return // Wait for initial load
+        if (!isAvailable) return
+
+        // Increment sequence to invalidate any pending async operations
+        urlChangeSequenceRef.current++
+        const currentSequence = urlChangeSequenceRef.current
+
+        async function handleSessionIdChange() {
+            if (initialSessionId) {
+                // URL has session ID - load it
+                const session = await getSession(initialSessionId)
+
+                // Check if this request is still the latest (sequence guard)
+                // If not, a newer URL change happened while we were loading
+                if (currentSequence !== urlChangeSequenceRef.current) {
+                    return
+                }
+
+                if (session) {
+                    // Only update if the session is different from current
+                    setCurrentSessionId((current) => {
+                        if (current !== session.id) {
+                            setCurrentSession(session)
+                            return session.id
+                        }
+                        return current
+                    })
+                }
+            }
+            // Removed: else clause that clears session
+            // Clearing is now handled explicitly by clearCurrentSession()
+            // This prevents race conditions when URL update is async
+        }
+
+        handleSessionIdChange()
+    }, [initialSessionId, isAvailable])
+
+    // Refresh sessions on window focus (multi-tab sync)
+    useEffect(() => {
+        const handleFocus = () => {
+            refreshSessions()
+        }
+        window.addEventListener("focus", handleFocus)
+        return () => window.removeEventListener("focus", handleFocus)
+    }, [refreshSessions])
+
+    // Switch to a different session
+    const switchSession = useCallback(
+        async (id: string): Promise<SessionData | null> => {
+            if (id === currentSessionId) return null
+
+            // Save current session first if it has messages
+            if (currentSession && currentSession.messages.length > 0) {
+                await saveSession(currentSession)
+            }
+
+            // Load the target session
+            const session = await getSession(id)
+            if (!session) {
+                console.error("Session not found:", id)
+                return null
+            }
+
+            // Update state
+            setCurrentSession(session)
+            setCurrentSessionId(session.id)
+
+            return {
+                messages: session.messages,
+                xmlSnapshots: session.xmlSnapshots,
+                diagramXml: session.diagramXml,
+                thumbnailDataUrl: session.thumbnailDataUrl,
+                diagramHistory: session.diagramHistory,
+            }
+        },
+        [currentSessionId, currentSession],
+    )
+
+    // Delete a session
+    const deleteSession = useCallback(
+        async (id: string): Promise<{ wasCurrentSession: boolean }> => {
+            const wasCurrentSession = id === currentSessionId
+            await deleteSessionFromDB(id)
+
+            // If deleting current session, clear state (caller will show new empty session)
+            if (wasCurrentSession) {
+                setCurrentSession(null)
+                setCurrentSessionId(null)
+            }
+
+            await refreshSessions()
+
+            return { wasCurrentSession }
+        },
+        [currentSessionId, refreshSessions],
+    )
+
+    // Save current session data (debounced externally by caller)
+    // forSessionId: if provided, verify save targets correct session (prevents stale debounce writes)
+    const saveCurrentSession = useCallback(
+        async (
+            data: SessionData,
+            forSessionId?: string | null,
+        ): Promise<void> => {
+            // If forSessionId is provided, verify it matches current session
+            // This prevents stale debounced saves from overwriting a newly switched session
+            if (
+                forSessionId !== undefined &&
+                forSessionId !== currentSessionId
+            ) {
+                return
+            }
+
+            if (!currentSession) {
+                // Create a new session if none exists
+                const newSession: ChatSession = {
+                    ...createEmptySession(),
+                    messages: data.messages,
+                    xmlSnapshots: data.xmlSnapshots,
+                    diagramXml: data.diagramXml,
+                    thumbnailDataUrl: data.thumbnailDataUrl,
+                    diagramHistory: data.diagramHistory,
+                    title: extractTitle(data.messages),
+                }
+                await saveSession(newSession)
+                await enforceSessionLimit()
+                setCurrentSession(newSession)
+                setCurrentSessionId(newSession.id)
+                await refreshSessions()
+                return
+            }
+
+            // Update existing session
+            const updatedSession: ChatSession = {
+                ...currentSession,
+                messages: data.messages,
+                xmlSnapshots: data.xmlSnapshots,
+                diagramXml: data.diagramXml,
+                thumbnailDataUrl:
+                    data.thumbnailDataUrl ?? currentSession.thumbnailDataUrl,
+                diagramHistory:
+                    data.diagramHistory ?? currentSession.diagramHistory,
+                updatedAt: Date.now(),
+                // Update title if it's still default and we have messages
+                title:
+                    currentSession.title === "New Chat" &&
+                    data.messages.length > 0
+                        ? extractTitle(data.messages)
+                        : currentSession.title,
+            }
+
+            await saveSession(updatedSession)
+            setCurrentSession(updatedSession)
+
+            // Update sessions list metadata
+            setSessions((prev) =>
+                prev.map((s) =>
+                    s.id === updatedSession.id
+                        ? {
+                              ...s,
+                              title: updatedSession.title,
+                              updatedAt: updatedSession.updatedAt,
+                              messageCount: updatedSession.messages.length,
+                              hasDiagram:
+                                  !!updatedSession.diagramXml &&
+                                  updatedSession.diagramXml.trim().length > 0,
+                              thumbnailDataUrl: updatedSession.thumbnailDataUrl,
+                          }
+                        : s,
+                ),
+            )
+        },
+        [currentSession, currentSessionId, refreshSessions],
+    )
+
+    // Clear current session state (for starting fresh without loading another session)
+    const clearCurrentSession = useCallback(() => {
+        setCurrentSession(null)
+        setCurrentSessionId(null)
+    }, [])
+
+    return {
+        sessions,
+        currentSessionId,
+        currentSession,
+        isLoading,
+        isAvailable,
+        switchSession,
+        deleteSession,
+        saveCurrentSession,
+        refreshSessions,
+        clearCurrentSession,
+    }
+}

lib/i18n/dictionaries/en.json

@@ -117,7 +117,8 @@
             "drawio": "Draw.io XML",
             "png": "PNG Image",
             "svg": "SVG Image"
-        }
+        },
+        "savedSuccessfully": "Saved successfully!"
     },
     "history": {
         "title": "Diagram History",
@@ -212,6 +213,22 @@
         "contactMe": "Contact Me",
         "usageNotice": "Due to high usage, I have changed the model from Claude to minimax-m2 and added some usage limits. See About page for details."
     },
+    "sessionHistory": {
+        "tooltip": "Chat History",
+        "newChat": "New Chat",
+        "empty": "No chat history yet",
+        "emptyHint": "Start a conversation to begin",
+        "today": "Today",
+        "yesterday": "Yesterday",
+        "thisWeek": "This Week",
+        "earlier": "Earlier",
+        "deleteTitle": "Delete this chat?",
+        "deleteDescription": "This will permanently delete this chat session and its diagram. This action cannot be undone.",
+        "recentChats": "Recent Chats",
+        "justNow": "Just now",
+        "searchPlaceholder": "Search chats...",
+        "noResults": "No chats found"
+    },
     "modelConfig": {
         "title": "AI Model Configuration",
         "description": "Configure multiple AI providers and models",

lib/i18n/dictionaries/ja.json

@@ -117,7 +117,8 @@
             "drawio": "Draw.io XML",
             "png": "PNG 画像",
             "svg": "SVG 画像"
-        }
+        },
+        "savedSuccessfully": "保存完了！"
     },
     "history": {
         "title": "ダイアグラム履歴",
@@ -212,6 +213,22 @@
         "contactMe": "お問い合わせ",
         "usageNotice": "利用量の増加に伴い、コスト削減のためモデルを Claude から minimax-m2 に変更し、いくつかの利用制限を設けました。詳細は概要ページをご覧ください。"
     },
+    "sessionHistory": {
+        "tooltip": "チャット履歴",
+        "newChat": "新しいチャット",
+        "empty": "チャット履歴はまだありません",
+        "emptyHint": "会話を始めてください",
+        "today": "今日",
+        "yesterday": "昨日",
+        "thisWeek": "今週",
+        "earlier": "それ以前",
+        "deleteTitle": "このチャットを削除しますか？",
+        "deleteDescription": "このチャットセッションとダイアグラムは完全に削除されます。この操作は取り消せません。",
+        "recentChats": "最近のチャット",
+        "justNow": "たった今",
+        "searchPlaceholder": "チャットを検索...",
+        "noResults": "チャットが見つかりません"
+    },
     "modelConfig": {
         "title": "AIモデル設定",
         "description": "複数のAIプロバイダーとモデルを設定",

lib/i18n/dictionaries/zh.json

@@ -117,7 +117,8 @@
             "drawio": "Draw.io XML",
             "png": "PNG 图片",
             "svg": "SVG 图片"
-        }
+        },
+        "savedSuccessfully": "保存成功！"
     },
     "history": {
         "title": "图表历史",
@@ -212,6 +213,22 @@
         "contactMe": "联系我",
         "usageNotice": "由于使用量过高，我已将模型从 Claude 更换为 minimax-m2，并设置了一些用量限制。详情请查看关于页面。"
     },
+    "sessionHistory": {
+        "tooltip": "聊天历史",
+        "newChat": "新对话",
+        "empty": "暂无聊天记录",
+        "emptyHint": "开始对话吧",
+        "today": "今天",
+        "yesterday": "昨天",
+        "thisWeek": "本周",
+        "earlier": "更早",
+        "deleteTitle": "删除此对话？",
+        "deleteDescription": "这将永久删除此聊天会话及其图表。此操作无法撤消。",
+        "recentChats": "最近对话",
+        "justNow": "刚刚",
+        "searchPlaceholder": "搜索对话...",
+        "noResults": "未找到对话"
+    },
     "modelConfig": {
         "title": "AI 模型配置",
         "description": "配置多个 AI 提供商和模型",

lib/session-storage.ts

@@ -0,0 +1,338 @@
+import { type DBSchema, type IDBPDatabase, openDB } from "idb"
+import { nanoid } from "nanoid"
+
+// Constants
+const DB_NAME = "next-ai-drawio"
+const DB_VERSION = 1
+const STORE_NAME = "sessions"
+const MIGRATION_FLAG = "next-ai-drawio-migrated-to-idb"
+const MAX_SESSIONS = 50
+
+// Types
+export interface ChatSession {
+    id: string
+    title: string
+    createdAt: number
+    updatedAt: number
+    messages: StoredMessage[]
+    xmlSnapshots: [number, string][]
+    diagramXml: string
+    thumbnailDataUrl?: string // Small PNG preview of the diagram
+    diagramHistory?: { svg: string; xml: string }[] // Version history of diagram edits
+}
+
+export interface StoredMessage {
+    id: string
+    role: "user" | "assistant" | "system"
+    parts: Array<{ type: string; [key: string]: unknown }>
+}
+
+export interface SessionMetadata {
+    id: string
+    title: string
+    createdAt: number
+    updatedAt: number
+    messageCount: number
+    hasDiagram: boolean
+    thumbnailDataUrl?: string
+}
+
+interface ChatSessionDB extends DBSchema {
+    sessions: {
+        key: string
+        value: ChatSession
+        indexes: { "by-updated": number }
+    }
+}
+
+// Database singleton
+let dbPromise: Promise<IDBPDatabase<ChatSessionDB>> | null = null
+
+async function getDB(): Promise<IDBPDatabase<ChatSessionDB>> {
+    if (!dbPromise) {
+        dbPromise = openDB<ChatSessionDB>(DB_NAME, DB_VERSION, {
+            upgrade(db, oldVersion) {
+                if (oldVersion < 1) {
+                    const store = db.createObjectStore(STORE_NAME, {
+                        keyPath: "id",
+                    })
+                    store.createIndex("by-updated", "updatedAt")
+                }
+                // Future migrations: if (oldVersion < 2) { ... }
+            },
+        })
+    }
+    return dbPromise
+}
+
+// Check if IndexedDB is available
+export function isIndexedDBAvailable(): boolean {
+    if (typeof window === "undefined") return false
+    try {
+        return "indexedDB" in window && window.indexedDB !== null
+    } catch {
+        return false
+    }
+}
+
+// CRUD Operations
+export async function getAllSessionMetadata(): Promise<SessionMetadata[]> {
+    if (!isIndexedDBAvailable()) return []
+    try {
+        const db = await getDB()
+        const tx = db.transaction(STORE_NAME, "readonly")
+        const index = tx.store.index("by-updated")
+        const metadata: SessionMetadata[] = []
+
+        // Use cursor to read only metadata fields (avoids loading full messages/XML)
+        let cursor = await index.openCursor(null, "prev") // newest first
+        while (cursor) {
+            const s = cursor.value
+            metadata.push({
+                id: s.id,
+                title: s.title,
+                createdAt: s.createdAt,
+                updatedAt: s.updatedAt,
+                messageCount: s.messages.length,
+                hasDiagram: !!s.diagramXml && s.diagramXml.trim().length > 0,
+                thumbnailDataUrl: s.thumbnailDataUrl,
+            })
+            cursor = await cursor.continue()
+        }
+        return metadata
+    } catch (error) {
+        console.error("Failed to get session metadata:", error)
+        return []
+    }
+}
+
+export async function getSession(id: string): Promise<ChatSession | null> {
+    if (!isIndexedDBAvailable()) return null
+    try {
+        const db = await getDB()
+        return (await db.get(STORE_NAME, id)) || null
+    } catch (error) {
+        console.error("Failed to get session:", error)
+        return null
+    }
+}
+
+export async function saveSession(session: ChatSession): Promise<boolean> {
+    if (!isIndexedDBAvailable()) return false
+    try {
+        const db = await getDB()
+        await db.put(STORE_NAME, session)
+        return true
+    } catch (error) {
+        // Handle quota exceeded
+        if (
+            error instanceof DOMException &&
+            error.name === "QuotaExceededError"
+        ) {
+            console.warn("Storage quota exceeded, deleting oldest session...")
+            await deleteOldestSession()
+            // Retry once
+            try {
+                const db = await getDB()
+                await db.put(STORE_NAME, session)
+                return true
+            } catch (retryError) {
+                console.error(
+                    "Failed to save session after cleanup:",
+                    retryError,
+                )
+                return false
+            }
+        } else {
+            console.error("Failed to save session:", error)
+            return false
+        }
+    }
+}
+
+export async function deleteSession(id: string): Promise<void> {
+    if (!isIndexedDBAvailable()) return
+    try {
+        const db = await getDB()
+        await db.delete(STORE_NAME, id)
+    } catch (error) {
+        console.error("Failed to delete session:", error)
+    }
+}
+
+export async function getSessionCount(): Promise<number> {
+    if (!isIndexedDBAvailable()) return 0
+    try {
+        const db = await getDB()
+        return await db.count(STORE_NAME)
+    } catch (error) {
+        console.error("Failed to get session count:", error)
+        return 0
+    }
+}
+
+export async function deleteOldestSession(): Promise<void> {
+    if (!isIndexedDBAvailable()) return
+    try {
+        const db = await getDB()
+        const tx = db.transaction(STORE_NAME, "readwrite")
+        const index = tx.store.index("by-updated")
+        const cursor = await index.openCursor()
+        if (cursor) {
+            await cursor.delete()
+        }
+        await tx.done
+    } catch (error) {
+        console.error("Failed to delete oldest session:", error)
+    }
+}
+
+// Enforce max sessions limit
+export async function enforceSessionLimit(): Promise<void> {
+    const count = await getSessionCount()
+    if (count > MAX_SESSIONS) {
+        const toDelete = count - MAX_SESSIONS
+        for (let i = 0; i < toDelete; i++) {
+            await deleteOldestSession()
+        }
+    }
+}
+
+// Helper: Create a new empty session
+export function createEmptySession(): ChatSession {
+    return {
+        id: nanoid(),
+        title: "New Chat",
+        createdAt: Date.now(),
+        updatedAt: Date.now(),
+        messages: [],
+        xmlSnapshots: [],
+        diagramXml: "",
+    }
+}
+
+// Helper: Extract title from first user message (truncated to reasonable length)
+const MAX_TITLE_LENGTH = 100
+
+export function extractTitle(messages: StoredMessage[]): string {
+    const firstUserMessage = messages.find((m) => m.role === "user")
+    if (!firstUserMessage) return "New Chat"
+
+    const textPart = firstUserMessage.parts.find((p) => p.type === "text")
+    if (!textPart || typeof textPart.text !== "string") return "New Chat"
+
+    const text = textPart.text.trim()
+    if (!text) return "New Chat"
+
+    // Truncate long titles
+    if (text.length > MAX_TITLE_LENGTH) {
+        return text.slice(0, MAX_TITLE_LENGTH).trim() + "..."
+    }
+    return text
+}
+
+// Helper: Sanitize UIMessage to StoredMessage
+export function sanitizeMessage(message: unknown): StoredMessage | null {
+    if (!message || typeof message !== "object") return null
+
+    const msg = message as Record<string, unknown>
+    if (!msg.id || !msg.role) return null
+
+    const role = msg.role as string
+    if (!["user", "assistant", "system"].includes(role)) return null
+
+    // Extract parts, removing streaming state artifacts
+    let parts: Array<{ type: string; [key: string]: unknown }> = []
+    if (Array.isArray(msg.parts)) {
+        parts = msg.parts.map((part: unknown) => {
+            if (!part || typeof part !== "object") return { type: "unknown" }
+            const p = part as Record<string, unknown>
+            // Remove streaming-related fields
+            const { isStreaming, streamingState, ...cleanPart } = p
+            return cleanPart as { type: string; [key: string]: unknown }
+        })
+    }
+
+    return {
+        id: msg.id as string,
+        role: role as "user" | "assistant" | "system",
+        parts,
+    }
+}
+
+export function sanitizeMessages(messages: unknown[]): StoredMessage[] {
+    return messages
+        .map(sanitizeMessage)
+        .filter((m): m is StoredMessage => m !== null)
+}
+
+// Migration from localStorage
+export async function migrateFromLocalStorage(): Promise<string | null> {
+    if (typeof window === "undefined") return null
+    if (!isIndexedDBAvailable()) return null
+
+    // Check if already migrated
+    if (localStorage.getItem(MIGRATION_FLAG)) return null
+
+    try {
+        const savedMessages = localStorage.getItem("next-ai-draw-io-messages")
+        const savedSnapshots = localStorage.getItem(
+            "next-ai-draw-io-xml-snapshots",
+        )
+        const savedXml = localStorage.getItem("next-ai-draw-io-diagram-xml")
+
+        let newSessionId: string | null = null
+        let migrationSucceeded = false
+
+        if (savedMessages) {
+            const messages = JSON.parse(savedMessages)
+            if (Array.isArray(messages) && messages.length > 0) {
+                const sanitized = sanitizeMessages(messages)
+                const session: ChatSession = {
+                    id: nanoid(),
+                    title: extractTitle(sanitized),
+                    createdAt: Date.now(),
+                    updatedAt: Date.now(),
+                    messages: sanitized,
+                    xmlSnapshots: savedSnapshots
+                        ? JSON.parse(savedSnapshots)
+                        : [],
+                    diagramXml: savedXml || "",
+                }
+                const saved = await saveSession(session)
+                if (saved) {
+                    // Verify the session was actually written
+                    const verified = await getSession(session.id)
+                    if (verified) {
+                        newSessionId = session.id
+                        migrationSucceeded = true
+                    }
+                }
+            } else {
+                // Empty array or invalid data - nothing to migrate, mark as success
+                migrationSucceeded = true
+            }
+        } else {
+            // No data to migrate - mark as success
+            migrationSucceeded = true
+        }
+
+        // Only clean up old data if migration succeeded
+        if (migrationSucceeded) {
+            localStorage.setItem(MIGRATION_FLAG, "true")
+            localStorage.removeItem("next-ai-draw-io-messages")
+            localStorage.removeItem("next-ai-draw-io-xml-snapshots")
+            localStorage.removeItem("next-ai-draw-io-diagram-xml")
+        } else {
+            console.warn(
+                "Migration to IndexedDB failed - keeping localStorage data for retry",
+            )
+        }
+
+        return newSessionId
+    } catch (error) {
+        console.error("Migration failed:", error)
+        // Don't mark as migrated - allow retry on next load
+        return null
+    }
+}

lib/storage.ts

@@ -1,13 +1,7 @@
-// Centralized localStorage keys
-// Consolidates all storage keys from chat-panel.tsx and settings-dialog.tsx
+// Centralized localStorage keys for quota tracking and settings
+// Chat data is now stored in IndexedDB via session-storage.ts
 
 export const STORAGE_KEYS = {
-    // Chat data
-    messages: "next-ai-draw-io-messages",
-    xmlSnapshots: "next-ai-draw-io-xml-snapshots",
-    diagramXml: "next-ai-draw-io-diagram-xml",
-    sessionId: "next-ai-draw-io-session-id",
-
     // Quota tracking
     requestCount: "next-ai-draw-io-request-count",
     requestDate: "next-ai-draw-io-request-date",

lib/utils.ts

@@ -6,6 +6,25 @@ export function cn(...inputs: ClassValue[]) {
     return twMerge(clsx(inputs))
 }
 
+// ============================================================================
+// Diagram Constants
+// ============================================================================
+
+/**
+ * Minimum length for a "real" diagram XML (not just empty template).
+ * Empty mxfile templates are ~147-300 chars; real diagrams are larger.
+ */
+export const MIN_REAL_DIAGRAM_LENGTH = 300
+
+/**
+ * Check if diagram XML represents a real diagram (not just empty template).
+ * @param xml - The diagram XML string to check
+ * @returns true if the XML is a real diagram with content
+ */
+export function isRealDiagram(xml: string | undefined | null): boolean {
+    return !!xml && xml.length > MIN_REAL_DIAGRAM_LENGTH
+}
+
 // ============================================================================
 // XML Validation/Fix Constants
 // ============================================================================

package.json

@@ -1,6 +1,6 @@
 {
     "name": "next-ai-draw-io",
-    "version": "0.4.7",
+    "version": "0.4.9",
     "license": "Apache-2.0",
     "private": true,
     "main": "dist-electron/main/index.js",
@@ -64,6 +64,7 @@
         "class-variance-authority": "^0.7.1",
         "clsx": "^2.1.1",
         "cmdk": "^1.1.1",
+        "idb": "^8.0.3",
         "js-tiktoken": "^1.0.21",
         "jsdom": "^27.0.0",
         "jsonrepair": "^3.13.1",
@@ -71,7 +72,7 @@
         "motion": "^12.23.25",
         "negotiator": "^1.0.0",
         "next": "^16.0.7",
-        "ollama-ai-provider-v2": "^1.5.4",
+        "ollama-ai-provider-v2": "^2.0.0",
         "pako": "^2.1.0",
         "prism-react-renderer": "^2.4.1",
         "react": "^19.1.2",
@@ -89,9 +90,9 @@
         "zod": "^4.1.12"
     },
     "optionalDependencies": {
+        "@tailwindcss/oxide-linux-x64-gnu": "^4.1.18",
         "lightningcss": "^1.30.2",
-        "lightningcss-linux-x64-gnu": "^1.30.2",
-        "@tailwindcss/oxide-linux-x64-gnu": "^4.1.18"
+        "lightningcss-linux-x64-gnu": "^1.30.2"
     },
     "lint-staged": {
         "*.{js,ts,jsx,tsx,json,css}": [

packages/mcp-server/README.md

@@ -64,6 +64,24 @@ Add to Cursor MCP config (`~/.cursor/mcp.json`):
 }
 ```
 
+### Cline (VS Code Extension)
+
+1. Click the **MCP Servers** icon in Cline's top menu bar
+2. Select the **Configure** tab
+3. Click **Configure MCP Servers** to edit `cline_mcp_settings.json`
+4. Add the drawio server:
+
+```json
+{
+  "mcpServers": {
+    "drawio": {
+      "command": "npx",
+      "args": ["@next-ai-drawio/mcp-server@latest"]
+    }
+  }
+}
+```
+
 ### Claude Code CLI
 
 ```bash

packages/mcp-server/src/http-server.ts

@@ -29,10 +29,27 @@ function getOrigin(url: string): string {
 
 const DRAWIO_ORIGIN = getOrigin(DRAWIO_BASE_URL)
 
+// Minimal blank diagram used to bootstrap new sessions.
+// This avoids the draw.io embed spinner (spin=1) getting stuck when no `load(xml)` is ever sent.
+const DEFAULT_DIAGRAM_XML = `<mxfile host="app.diagrams.net"><diagram id="blank" name="Page-1"><mxGraphModel><root><mxCell id="0"/><mxCell id="1" parent="0"/></root></mxGraphModel></diagram></mxfile>`
+
 // Normalize URL for iframe src - ensure no double slashes
 function normalizeUrl(url: string): string {
     // Remove trailing slash to avoid double slashes
-    return url.replace(/\/$/, '')
+    return url.replace(/\/$/, "")
+}
+
+function isLikelyMcpSessionId(sessionId: string): boolean {
+    // Keep this cheap and conservative to avoid creating state for arbitrary IDs.
+    return sessionId.startsWith("mcp-") && sessionId.length <= 128
+}
+
+function ensureSessionStateInitialized(sessionId: string): void {
+    if (!sessionId) return
+    if (!isLikelyMcpSessionId(sessionId)) return
+    if (stateStore.has(sessionId)) return
+
+    setState(sessionId, DEFAULT_DIAGRAM_XML)
 }
 
 interface SessionState {
@@ -177,8 +194,11 @@ function handleRequest(
     }
 
     if (url.pathname === "/" || url.pathname === "/index.html") {
+        const sessionId = url.searchParams.get("mcp") || ""
+        ensureSessionStateInitialized(sessionId)
+
         res.writeHead(200, { "Content-Type": "text/html" })
-        res.end(getHtmlPage(url.searchParams.get("mcp") || ""))
+        res.end(getHtmlPage(sessionId))
     } else if (url.pathname === "/api/state") {
         handleStateApi(req, res, url)
     } else if (url.pathname === "/api/history") {
@@ -205,6 +225,7 @@ function handleStateApi(
             res.end(JSON.stringify({ error: "sessionId required" }))
             return
         }
+        ensureSessionStateInitialized(sessionId)
         const state = stateStore.get(sessionId)
         res.writeHead(200, { "Content-Type": "application/json" })
         res.end(