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frontend-web/docs/openCanvas-progress.md

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+# Open Canvas 集成进度文档
+
+> 更新时间：2026-05-15
+> 当前分支：dhk-1
+
+---
+
+## 一、整体进度概览
+
+| 阶段 | 名称 | 状态 |
+|------|------|------|
+| 前端阶段一 | 路由与目录骨架 | ✅ 已完成 |
+| 前端阶段二 | Canvas 双栏布局 | ✅ 已完成 |
+| 前端阶段三 | 类型与状态协议 | ✅ 已完成（随阶段一一并完成） |
+| 后端阶段一 | ThreadState 扩展 | ✅ 已完成 |
+| 后端阶段二 | canvas_agent 注册 + 最小节点闭环 | ✅ 已完成 |
+| 前端阶段四 | API 适配层 | ✅ 已完成 |
+| 前端阶段五 | 线程与流式状态接入 | ✅ 已完成 |
+| 前端阶段六 | Artifact 渲染器增强（CodeMirror / Markdown） | ✅ 已完成 |
+| 前后端阶段七 | 局部选区改写 | ✅ 已完成 |
+| 前后端阶段八 | 快捷动作系统 | ⬜ 待开始 |
+| 前后端阶段九 | 本地模型支持完善 | ⬜ 待开始 |
+
+**下一个要做的任务**：前后端阶段八 — 快捷动作系统（CanvasEmptyState 模板触发 + 快捷动作按钮）
+
+---
+
+## 二、已完成工作详情
+
+### 2.1 前端路由接入
+
+修改了 `frontend-web/src/pages/PageRoutes.tsx`：
+
+```tsx
+import OpenCanvasRoutes from "@/open-canvas/routes/OpenCanvasRoutes";
+// 在 PageLayout 内部添加：
+<Route path="canvas/*" element={<OpenCanvasRoutes />} />
+```
+
+子路由：
+- `/page/canvas` → `CanvasHomePage`（欢迎页 + 快速开始）
+- `/page/canvas/:thread_id` → `CanvasThreadPage`（主工作区）
+
+### 2.2 前端目录结构（已建立，26 个文件）
+
+```
+frontend-web/src/open-canvas/
+  api/
+    client.ts          # stub，Phase 5 实现
+    models.ts          # stub，Phase 5 实现
+    threads.ts         # stub，Phase 5 实现
+    runs.ts            # stub，Phase 5 实现
+  components/
+    layout/
+      CanvasShell.tsx              # 顶层布局壳，flex-col
+      CanvasHeader.tsx             # 顶部栏：返回键、折叠按钮、标题、流式指示
+      CanvasResizableLayout.tsx    # 左右可拖拽双栏（react-resizable-panels）
+    chat/
+      CanvasChatPanel.tsx          # 左栏：欢迎状态 + 消息列表 + 禁用输入框
+    artifact/
+      CanvasArtifactPanel.tsx      # 右栏：空状态或渲染器
+      CanvasArtifactHeader.tsx     # 右栏顶部：图标、标题、语言 Badge、版本导航
+      CanvasArtifactVersionNav.tsx # 版本 prev/next 导航
+      CanvasEmptyState.tsx         # 空状态：5 种快速开始模板
+      TextArtifactRenderer.tsx     # 文本渲染（Phase 6 增强为 Markdown）
+      CodeArtifactRenderer.tsx     # 代码渲染（Phase 6 增强为 CodeMirror）
+  contexts/
+    CanvasThreadContext.tsx        # threadId、modelName
+    CanvasGraphContext.tsx         # messages、artifact、isStreaming
+    CanvasUIContext.tsx            # isChatCollapsed、isEditing、selection 等 UI 状态
+  hooks/
+    useCanvasStream.ts             # stub，Phase 5 实现
+    useCanvasArtifact.ts           # stub，Phase 6 实现
+    useCanvasSelection.ts          # stub，Phase 7 实现
+    useCanvasQuickActions.ts       # stub，Phase 8 实现
+  pages/
+    CanvasHomePage.tsx             # 欢迎页 + 快速开始入口
+    CanvasThreadPage.tsx           # 三层 Provider 装配 + CanvasShell
+  routes/
+    OpenCanvasRoutes.tsx           # React Router 子路由
+  types/
+    artifact.ts                    # CanvasArtifact、CanvasArtifactText、CanvasArtifactCode
+    thread.ts                      # CanvasMessage、CanvasThreadValues、CanvasThreadMetadata
+    model.ts                       # CanvasModel（含 supports_canvas_* 能力字段）
+    selection.ts                   # CanvasTextSelection、CanvasCodeSelection
+    quick-action.ts                # QuickAction、QuickActionId
+  utils/
+    artifact.ts                    # getCurrentArtifactContent、appendArtifactVersion 等工具
+    selection.ts                   # stub
+    thread.ts                      # stub
+    stream.ts                      # stub
+    quick-actions.ts               # stub
+  constants/
+    index.ts                       # CANVAS_AGENT_ID、PROGRAMMING_LANGUAGES、QUICK_ACTIONS_*
+```
+
+### 2.3 核心类型定义
+
+```ts
+// types/artifact.ts
+export type CanvasArtifact = {
+  currentIndex: number;                          // 从 1 开始
+  contents: CanvasArtifactContent[];
+};
+
+export type CanvasArtifactText = {
+  index: number; type: "text"; title: string; fullMarkdown: string;
+};
+
+export type CanvasArtifactCode = {
+  index: number; type: "code"; title: string;
+  language: ProgrammingLanguageOptions; code: string;
+};
+```
+
+### 2.4 Context 结构
+
+```tsx
+// CanvasThreadPage.tsx 的装配顺序
+<CanvasThreadProvider initialThreadId={thread_id}>
+  <CanvasGraphProvider>
+    <CanvasUIProvider>
+      <CanvasShell />
+    </CanvasUIProvider>
+  </CanvasGraphProvider>
+</CanvasThreadProvider>
+```
+
+---
+
+## 三、已解决的技术难题
+
+### 3.1 react-resizable-panels v4.6.2 API 差异
+
+此版本与旧版 API 不同，必须使用：
+
+```tsx
+// ✅ 正确写法
+import type { GroupImperativeHandle } from "react-resizable-panels";
+const layoutRef = useRef<GroupImperativeHandle>(null);
+
+<ResizablePanelGroup
+  orientation="horizontal"      // ← 不是 direction
+  groupRef={layoutRef}          // ← 不是 ref
+>
+  <ResizablePanel id="chat" ... />      // ← 必须有 id
+  <ResizablePanel id="artifact" ... />  // ← 必须有 id
+</ResizablePanelGroup>
+
+// 切换折叠
+layoutRef.current?.setLayout({ chat: 0, artifact: 100 });  // ← 对象形式，非数组
+```
+
+### 3.2 Flex 高度链（防止底部内容被裁剪）
+
+```
+PageLayout（h-screen）
+  └── main（flex-1）
+        └── CanvasShell div（h-full flex flex-col）
+              └── CanvasResizableLayout wrapper（flex-1 min-h-0 overflow-hidden）← 关键
+                    └── ResizablePanelGroup（h-full）
+                          └── 面板内容（h-full）
+```
+
+**`min-h-0` 是必须的**，否则 flex 子项不会收缩，底部内容被推出屏幕外。
+
+### 3.3 折叠/展开按钮
+
+`CanvasHeader.tsx` 中通过 `useCanvasUIContext()` 控制 `isChatCollapsed`，
+`CanvasResizableLayout.tsx` 中用 `useEffect` 监听并调用 `setLayout`：
+
+```tsx
+useEffect(() => {
+  layoutRef.current?.setLayout(
+    isChatCollapsed ? { chat: 0, artifact: 100 } : { chat: 35, artifact: 65 }
+  );
+}, [isChatCollapsed]);
+```
+
+---
+
+## 四、下一步：后端 ThreadState 扩展
+
+**目标文件**：`offline-backend-20260512/backend/packages/harness/deerflow/agents/thread_state.py`
+
+**任务**：在现有 `ThreadState` 中新增以下 Canvas 专用字段，不影响 `artifacts: list[str]`（文件产物）：
+
+```python
+# 新增 TypedDict（建议单独定义）
+class CanvasArtifactText(TypedDict):
+    index: int
+    type: Literal["text"]
+    title: str
+    fullMarkdown: str
+
+class CanvasArtifactCode(TypedDict):
+    index: int
+    type: Literal["code"]
+    title: str
+    language: str
+    code: str
+
+class CanvasArtifact(TypedDict):
+    currentIndex: int
+    contents: list[CanvasArtifactText | CanvasArtifactCode]
+
+# 在 ThreadState 中新增字段
+artifact: Optional[CanvasArtifact]          # Canvas 主文档（区别于 artifacts 文件列表）
+highlighted_text: Optional[str]             # 用户选中的文本片段
+highlighted_code: Optional[str]             # 用户选中的代码片段
+canvas_mode: Optional[Literal["text", "code"]]
+quick_action_id: Optional[str]             # 快捷动作 id
+web_search_enabled: bool                   # 默认 False
+web_search_results: Optional[list[dict]]
+```
+
+**验收标准**：
+- 旧线程无 `artifact` 字段时不报错
+- `pnpm typecheck` 无新增错误（前端字段已对齐）
+- `make test` 全量回归通过
+
+**之后紧接**：`canvas_agent` 注册 + `factory.py` 修改 + 最小节点闭环
+
+---
+
+## 五、关键文件位置
+
+| 文件 | 用途 |
+|------|------|
+| `frontend-web/docs/openCanvas.md` | 主需求文档 |
+| `frontend-web/docs/openCanvas-frontend-checklist.md` | 前端详细清单 |
+| `frontend-web/docs/openCanvas-backend-checklist.md` | 后端详细清单 |
+| `frontend-web/docs/openCanvas-progress.md` | 本进度文档 |
+| `F:\react01\openCanvas` | open-canvas 源码参考（本地克隆） |
+| `offline-backend-20260512/backend/packages/harness/deerflow/agents/thread_state.py` | 下一步主改文件 |
+| `offline-backend-20260512/backend/packages/harness/deerflow/agents/factory.py` | canvas_agent 注册位置 |
+
+---
+
+## 六、架构决策记录
+
+| 决策 | 内容 |
+|------|------|
+| canvas_agent 方案 | 新增独立 canvas_agent，不改 lead_agent（方案 A）|
+| 路由形式 | `/page/canvas/*`，挂在 PageLayout 内 |
+| artifact 字段共存 | `artifact`（Canvas 文档）与 `artifacts: list[str]`（文件列表）独立共存 |
+| 模型配置真源 | 后端 config.yaml，前端动态加载 /api/models |
+| 前端 artifact 索引 | 从 1 开始（与 open-canvas 对齐） |
+| 流式首版策略 | 节点完成后输出完整 artifact 对象，不做 token 级局部流 |
+
+---
+
+## 七、开始新对话的推荐提示词
+
+```
+我们在集成 open-canvas 到 DeerFlow 项目。
+参考进度文档：frontend-web/docs/openCanvas-progress.md
+目前前端阶段一/二/三已完成，下一步是后端 ThreadState 扩展。
+请从第四节"下一步：后端 ThreadState 扩展"开始继续。
+```

frontend-web/src/open-canvas/api/client.ts

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+export { getAPIClient } from "@/core/api";

frontend-web/src/open-canvas/api/models.ts

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+import { apiFetch } from "@/core/api";
+import { getBackendBaseURL } from "@/core/config";
+
+import type { CanvasModel } from "../types/model";
+
+interface BackendModel {
+  name: string;
+  display_name?: string;
+  provider?: string;
+  is_local?: boolean;
+  supports_vision?: boolean;
+  supports_thinking?: boolean;
+  supports_reasoning_effort?: boolean;
+  supports_tool_calling?: boolean;
+}
+
+export async function loadCanvasModels(): Promise<CanvasModel[]> {
+  const res = await apiFetch(`${getBackendBaseURL()}/api/models`);
+  const data = (await res.json()) as { models?: BackendModel[] };
+  return (data.models ?? []).map(
+    (m): CanvasModel => ({
+      name: m.name,
+      display_name: m.display_name ?? m.name,
+      provider: m.provider,
+      is_local: m.is_local,
+      supports_vision: m.supports_vision,
+      supports_thinking: m.supports_thinking,
+      supports_reasoning_effort: m.supports_reasoning_effort,
+      supports_tool_calling: m.supports_tool_calling ?? true,
+      supports_canvas_generation: true,
+      supports_canvas_rewrite: true,
+      supports_canvas_code_edit: true,
+      supports_streaming_text: true,
+      supports_streaming_tool_calls: m.supports_tool_calling ?? true,
+    }),
+  );
+}

frontend-web/src/open-canvas/api/runs.ts

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+import { getAPIClient } from "@/core/api";
+
+import { CANVAS_AGENT_ID } from "../constants";
+import type { CanvasArtifact } from "../types/artifact";
+import type { CanvasMessage } from "../types/thread";
+
+export type CanvasRunInput = {
+  messages: Array<{ type: string; content: string }>;
+  canvas_mode?: "text" | "code";
+  highlighted_text?: string;
+  highlighted_code?: string;
+  quick_action_id?: string;
+};
+
+export type CanvasStreamCallbacks = {
+  onMessage?: (msg: CanvasMessage) => void;
+  onArtifact?: (artifact: CanvasArtifact) => void;
+  onDone?: () => void;
+  onError?: (err: unknown) => void;
+};
+
+export async function streamCanvasRun(
+  threadId: string,
+  input: CanvasRunInput,
+  callbacks: CanvasStreamCallbacks,
+): Promise<void> {
+  const client = getAPIClient();
+  try {
+    const stream = client.runs.stream(threadId, CANVAS_AGENT_ID, {
+      input,
+      streamMode: ["values", "messages-tuple"],
+    });
+
+    for await (const chunk of stream) {
+      // Cast to string: SDK typings only list a subset of event names
+      const event = chunk.event as string;
+      const data = (chunk as { event: string; data: unknown }).data;
+      if (event === "values") {
+        const state = data as Record<string, unknown>;
+        if (state.artifact) {
+          callbacks.onArtifact?.(state.artifact as CanvasArtifact);
+        }
+      } else if (event === "messages/tuple") {
+        const [msg] = data as [CanvasMessage];
+        if (msg) {
+          callbacks.onMessage?.(msg);
+        }
+      }
+    }
+    callbacks.onDone?.();
+  } catch (err) {
+    callbacks.onError?.(err);
+  }
+}
+
+export async function stopCanvasRun(
+  threadId: string,
+  runId: string,
+): Promise<void> {
+  const client = getAPIClient();
+  await client.runs.cancel(threadId, runId);
+}

frontend-web/src/open-canvas/api/threads.ts

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+import { getAPIClient } from "@/core/api";
+
+import { CANVAS_THREAD_METADATA } from "../constants";
+import type { CanvasThreadMetadata, CanvasThreadValues } from "../types/thread";
+
+export async function createCanvasThread(
+  metadata?: Partial<CanvasThreadMetadata>,
+): Promise<string> {
+  const client = getAPIClient();
+  const thread = await client.threads.create({
+    metadata: { ...CANVAS_THREAD_METADATA, ...metadata },
+  });
+  return thread.thread_id;
+}
+
+export async function getCanvasThread(
+  threadId: string,
+): Promise<CanvasThreadValues | null> {
+  const client = getAPIClient();
+  try {
+    const state =
+      await client.threads.getState<CanvasThreadValues>(threadId);
+    return (state.values as CanvasThreadValues) ?? null;
+  } catch {
+    return null;
+  }
+}
+
+export async function updateCanvasThreadState(
+  threadId: string,
+  values: Partial<CanvasThreadValues>,
+): Promise<void> {
+  const client = getAPIClient();
+  await client.threads.updateState(threadId, { values });
+}

frontend-web/src/open-canvas/components/artifact/CanvasArtifactHeader.tsx

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+import { FileText, Code2 } from "lucide-react";
+
+import { Badge } from "@/components/ui/badge";
+
+import { useCanvasGraphContext } from "../../contexts/CanvasGraphContext";
+import { getCurrentArtifactContent } from "../../utils/artifact";
+import { CanvasArtifactVersionNav } from "./CanvasArtifactVersionNav";
+
+export function CanvasArtifactHeader() {
+  const { artifact } = useCanvasGraphContext();
+  const content = getCurrentArtifactContent(artifact);
+
+  if (!content) return null;
+
+  const isCode = content.type === "code";
+  const Icon = isCode ? Code2 : FileText;
+
+  return (
+    <div className="h-11 border-b flex items-center px-4 gap-2 shrink-0 bg-background">
+      <Icon className="h-4 w-4 text-muted-foreground shrink-0" />
+
+      <span className="text-sm font-medium truncate flex-1 min-w-0">
+        {content.title}
+      </span>
+
+      <div className="flex items-center gap-2 shrink-0">
+        <Badge variant="secondary" className="text-[10px] h-5 px-1.5">
+          {isCode ? (content as { language: string }).language : "文本"}
+        </Badge>
+        <CanvasArtifactVersionNav />
+      </div>
+    </div>
+  );
+}

frontend-web/src/open-canvas/components/artifact/CanvasArtifactPanel.tsx

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+import { useSearchParams } from "react-router-dom";
+
+import { useCanvasGraphContext } from "../../contexts/CanvasGraphContext";
+import { getCurrentArtifactContent, isCodeArtifact } from "../../utils/artifact";
+import { CanvasArtifactHeader } from "./CanvasArtifactHeader";
+import { CanvasEmptyState } from "./CanvasEmptyState";
+import { TextArtifactRenderer } from "./TextArtifactRenderer";
+import { CodeArtifactRenderer } from "./CodeArtifactRenderer";
+import type {
+  CanvasArtifactCode,
+  CanvasArtifactText,
+} from "../../types/artifact";
+
+export function CanvasArtifactPanel() {
+  const { artifact } = useCanvasGraphContext();
+  const [searchParams] = useSearchParams();
+  const initialType = searchParams.get("type") as "text" | "code" | null;
+
+  if (!artifact) {
+    return (
+      <div className="h-full bg-muted/10">
+        <CanvasEmptyState initialType={initialType} />
+      </div>
+    );
+  }
+
+  const content = getCurrentArtifactContent(artifact);
+
+  return (
+    <div className="h-full flex flex-col overflow-hidden">
+      <CanvasArtifactHeader />
+      <div className="flex-1 overflow-hidden">
+        {content && isCodeArtifact(content) ? (
+          <CodeArtifactRenderer content={content as CanvasArtifactCode} />
+        ) : content ? (
+          <TextArtifactRenderer content={content as CanvasArtifactText} />
+        ) : null}
+      </div>
+    </div>
+  );
+}

frontend-web/src/open-canvas/components/artifact/CanvasArtifactVersionNav.tsx

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+import { ChevronLeft, ChevronRight } from "lucide-react";
+
+import { Button } from "@/components/ui/button";
+
+import { useCanvasGraphContext } from "../../contexts/CanvasGraphContext";
+import { setCurrentArtifactIndex } from "../../utils/artifact";
+
+export function CanvasArtifactVersionNav() {
+  const { artifact, setArtifact } = useCanvasGraphContext();
+
+  if (!artifact || artifact.contents.length <= 1) return null;
+
+  const total = artifact.contents.length;
+  const current = artifact.currentIndex;
+  const canGoPrev = current > 1;
+  const canGoNext = current < total;
+
+  function go(delta: -1 | 1) {
+    if (!artifact) return;
+    setArtifact(setCurrentArtifactIndex(artifact, current + delta));
+  }
+
+  return (
+    <div className="flex items-center gap-0.5">
+      <Button
+        variant="ghost"
+        size="icon"
+        className="h-6 w-6"
+        onClick={() => go(-1)}
+        disabled={!canGoPrev}
+        title="上一个版本"
+      >
+        <ChevronLeft className="h-3.5 w-3.5" />
+      </Button>
+      <span className="text-xs text-muted-foreground tabular-nums w-10 text-center">
+        {current}/{total}
+      </span>
+      <Button
+        variant="ghost"
+        size="icon"
+        className="h-6 w-6"
+        onClick={() => go(1)}
+        disabled={!canGoNext}
+        title="下一个版本"
+      >
+        <ChevronRight className="h-3.5 w-3.5" />
+      </Button>
+    </div>
+  );
+}

frontend-web/src/open-canvas/components/artifact/CanvasEmptyState.tsx

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+import { FileText, Code2, Globe, Atom, Terminal } from "lucide-react";
+import type { LucideIcon } from "lucide-react";
+
+import { useCanvasGraphContext } from "../../contexts/CanvasGraphContext";
+import { createDraftArtifact } from "../../utils/artifact";
+import type { ProgrammingLanguageOptions } from "../../types/artifact";
+
+const HTML_TEMPLATE = `<!DOCTYPE html>
+<html lang="zh-CN">
+<head>
+  <meta charset="UTF-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1.0">
+  <title>页面标题</title>
+  <style>
+    body { font-family: sans-serif; margin: 2rem; color: #333; }
+  </style>
+</head>
+<body>
+  <h1>Hello World</h1>
+  <p>在这里开始编写你的页面</p>
+</body>
+</html>`;
+
+const REACT_TEMPLATE = `import React from "react";
+
+interface Props {
+  // 在这里定义 props
+}
+
+export default function MyComponent({}: Props) {
+  return (
+    <div>
+      <h1>My Component</h1>
+      <p>在这里开始编写你的组件</p>
+    </div>
+  );
+}`;
+
+const PYTHON_TEMPLATE = `def main():
+    """主函数"""
+    print("Hello, World!")
+
+
+if __name__ == "__main__":
+    main()`;
+
+interface QuickStartOption {
+  icon: LucideIcon;
+  title: string;
+  description: string;
+  type: "text" | "code";
+  templateTitle: string;
+  content: string;
+  language?: ProgrammingLanguageOptions;
+}
+
+const QUICK_START_OPTIONS: QuickStartOption[] = [
+  {
+    icon: FileText,
+    title: "空白文档",
+    description: "从空白 Markdown 文档开始",
+    type: "text",
+    templateTitle: "未命名文档",
+    content: "",
+  },
+  {
+    icon: Code2,
+    title: "空白代码",
+    description: "从空白代码文件开始",
+    type: "code",
+    templateTitle: "未命名代码",
+    content: "",
+    language: "python",
+  },
+  {
+    icon: Globe,
+    title: "HTML 页面",
+    description: "基础 HTML 页面模板",
+    type: "code",
+    templateTitle: "HTML 页面",
+    content: HTML_TEMPLATE,
+    language: "html",
+  },
+  {
+    icon: Atom,
+    title: "React 组件",
+    description: "TypeScript React 组件模板",
+    type: "code",
+    templateTitle: "React 组件",
+    content: REACT_TEMPLATE,
+    language: "typescript",
+  },
+  {
+    icon: Terminal,
+    title: "Python 脚本",
+    description: "Python 入口脚本模板",
+    type: "code",
+    templateTitle: "Python 脚本",
+    content: PYTHON_TEMPLATE,
+    language: "python",
+  },
+];
+
+interface CanvasEmptyStateProps {
+  initialType?: "text" | "code" | null;
+}
+
+export function CanvasEmptyState({ initialType }: CanvasEmptyStateProps) {
+  const { setArtifact } = useCanvasGraphContext();
+
+  function handleSelect(option: QuickStartOption) {
+    setArtifact(
+      createDraftArtifact(option.type, {
+        title: option.templateTitle,
+        content: option.content,
+        language: option.language,
+      }),
+    );
+  }
+
+  const filtered =
+    initialType
+      ? QUICK_START_OPTIONS.filter(
+          (o) => !initialType || o.type === initialType || o.type === "text",
+        )
+      : QUICK_START_OPTIONS;
+
+  return (
+    <div className="h-full flex flex-col items-center justify-center px-6">
+      <div className="w-full max-w-sm space-y-6">
+        <div className="text-center space-y-1">
+          <p className="text-sm font-medium">选择模板快速开始</p>
+          <p className="text-xs text-muted-foreground">
+            或直接在左侧聊天区发送消息
+          </p>
+        </div>
+
+        <div className="space-y-2">
+          {QUICK_START_OPTIONS.map((option) => {
+            const Icon = option.icon;
+            const isHighlighted = initialType && option.type === initialType && option.content === "";
+            return (
+              <button
+                key={option.title}
+                onClick={() => handleSelect(option)}
+                className={`w-full flex items-center gap-3 rounded-lg border px-4 py-3 text-left transition-all hover:border-primary/50 hover:bg-accent/40 focus:outline-none focus-visible:ring-2 focus-visible:ring-ring ${
+                  isHighlighted
+                    ? "border-primary/40 bg-primary/5"
+                    : "bg-card"
+                }`}
+              >
+                <div className="w-8 h-8 rounded-md bg-muted flex items-center justify-center shrink-0">
+                  <Icon className="w-4 h-4 text-muted-foreground" />
+                </div>
+                <div className="min-w-0">
+                  <p className="text-sm font-medium truncate">{option.title}</p>
+                  <p className="text-xs text-muted-foreground truncate">
+                    {option.description}
+                  </p>
+                </div>
+              </button>
+            );
+          })}
+        </div>
+      </div>
+    </div>
+  );
+}

frontend-web/src/open-canvas/components/artifact/CodeArtifactRenderer.tsx

@@ -0,0 +1,120 @@
+import { html } from "@codemirror/lang-html";
+import { javascript } from "@codemirror/lang-javascript";
+import { json } from "@codemirror/lang-json";
+import { python } from "@codemirror/lang-python";
+import type { Extension } from "@codemirror/state";
+import type { ViewUpdate } from "@codemirror/view";
+import { basicLightInit } from "@uiw/codemirror-theme-basic";
+import { monokaiInit } from "@uiw/codemirror-theme-monokai";
+import CodeMirror from "@uiw/react-codemirror";
+import { useTheme } from "next-themes";
+import { useCallback, useMemo } from "react";
+
+import type {
+  CanvasArtifactCode,
+  ProgrammingLanguageOptions,
+} from "../../types/artifact";
+import { useCanvasSelection } from "../../hooks/useCanvasSelection";
+
+// ---------------------------------------------------------------------------
+// Themes — match code-editor.tsx defaults
+// ---------------------------------------------------------------------------
+
+const darkTheme = monokaiInit({
+  settings: {
+    background: "transparent",
+    gutterBackground: "transparent",
+    gutterForeground: "#555",
+    gutterActiveForeground: "#fff",
+    fontSize: "var(--text-sm)",
+  },
+});
+
+const lightTheme = basicLightInit({
+  settings: {
+    background: "transparent",
+    fontSize: "var(--text-sm)",
+  },
+});
+
+// ---------------------------------------------------------------------------
+// Language detection
+// ---------------------------------------------------------------------------
+
+function getLanguageExtension(
+  lang: ProgrammingLanguageOptions,
+): Extension | null {
+  switch (lang) {
+    case "typescript":
+      return javascript({ typescript: true, jsx: true });
+    case "javascript":
+      return javascript({ jsx: true });
+    case "python":
+      return python();
+    case "html":
+      return html();
+    case "json":
+      return json();
+    // cpp, java, rust, sql, xml, clojure, csharp, php → plain text fallback
+    default:
+      return null;
+  }
+}
+
+// ---------------------------------------------------------------------------
+// Component
+// ---------------------------------------------------------------------------
+
+interface CodeArtifactRendererProps {
+  content: CanvasArtifactCode;
+}
+
+export function CodeArtifactRenderer({ content }: CodeArtifactRendererProps) {
+  const { resolvedTheme } = useTheme();
+  const { handleCodeSelectionChange } = useCanvasSelection();
+
+  const extensions = useMemo<Extension[]>(() => {
+    const ext = getLanguageExtension(content.language);
+    return ext ? [ext] : [];
+  }, [content.language]);
+
+  const handleUpdate = useCallback(
+    (update: ViewUpdate) => {
+      if (!update.selectionSet) return;
+      const { from, to } = update.state.selection.main;
+      handleCodeSelectionChange(from, to);
+    },
+    [handleCodeSelectionChange],
+  );
+
+  if (!content.code) {
+    return (
+      <div className="h-full flex items-center justify-center">
+        <p className="text-sm text-muted-foreground">
+          空白代码，发送消息让 AI 填充内容
+        </p>
+      </div>
+    );
+  }
+
+  return (
+    <div className="h-full overflow-auto">
+      <CodeMirror
+        value={content.code}
+        readOnly
+        height="100%"
+        className="h-full font-mono [&_.cm-editor]:h-full [&_.cm-focused]:outline-none!"
+        theme={resolvedTheme === "dark" ? darkTheme : lightTheme}
+        extensions={extensions}
+        onUpdate={handleUpdate}
+        basicSetup={{
+          lineNumbers: true,
+          foldGutter: true,
+          highlightActiveLine: false,
+          highlightActiveLineGutter: false,
+          autocompletion: false,
+        }}
+      />
+    </div>
+  );
+}

frontend-web/src/open-canvas/components/artifact/TextArtifactRenderer.tsx

@@ -0,0 +1,142 @@
+import ReactMarkdown from "react-markdown";
+import remarkGfm from "remark-gfm";
+
+import type { CanvasArtifactText } from "../../types/artifact";
+import { useCanvasSelection } from "../../hooks/useCanvasSelection";
+
+interface TextArtifactRendererProps {
+  content: CanvasArtifactText;
+}
+
+export function TextArtifactRenderer({ content }: TextArtifactRendererProps) {
+  const { handleTextPointerUp } = useCanvasSelection();
+
+  if (!content.fullMarkdown) {
+    return (
+      <div className="h-full flex items-center justify-center">
+        <p className="text-sm text-muted-foreground">
+          空白文档，发送消息让 AI 填充内容
+        </p>
+      </div>
+    );
+  }
+
+  return (
+    <div
+      className="h-full overflow-y-auto"
+      onMouseUp={() => handleTextPointerUp(content.fullMarkdown)}
+    >
+      <div className="max-w-3xl mx-auto px-8 py-8">
+        <ReactMarkdown
+          remarkPlugins={[remarkGfm]}
+          components={{
+            h1: ({ children }) => (
+              <h1 className="text-2xl font-bold mb-4 mt-6 first:mt-0 text-foreground border-b border-border pb-2">
+                {children}
+              </h1>
+            ),
+            h2: ({ children }) => (
+              <h2 className="text-xl font-semibold mb-3 mt-6 text-foreground">
+                {children}
+              </h2>
+            ),
+            h3: ({ children }) => (
+              <h3 className="text-base font-semibold mb-2 mt-4 text-foreground">
+                {children}
+              </h3>
+            ),
+            h4: ({ children }) => (
+              <h4 className="text-sm font-semibold mb-2 mt-3 text-foreground">
+                {children}
+              </h4>
+            ),
+            p: ({ children }) => (
+              <p className="mb-4 leading-7 text-sm text-foreground/90">
+                {children}
+              </p>
+            ),
+            ul: ({ children }) => (
+              <ul className="mb-4 ml-5 list-disc space-y-1.5 text-sm text-foreground/90">
+                {children}
+              </ul>
+            ),
+            ol: ({ children }) => (
+              <ol className="mb-4 ml-5 list-decimal space-y-1.5 text-sm text-foreground/90">
+                {children}
+              </ol>
+            ),
+            li: ({ children }) => (
+              <li className="leading-7">{children}</li>
+            ),
+            blockquote: ({ children }) => (
+              <blockquote className="border-l-4 border-primary/30 pl-4 my-4 text-muted-foreground italic text-sm">
+                {children}
+              </blockquote>
+            ),
+            pre: ({ children }) => (
+              <pre className="mb-4 rounded-md bg-muted/60 overflow-x-auto">
+                {children}
+              </pre>
+            ),
+            code: ({ className, children }) => {
+              const isBlock = Boolean(className?.startsWith("language-"));
+              if (isBlock) {
+                return (
+                  <code className="block p-4 text-xs font-mono text-foreground leading-relaxed">
+                    {children}
+                  </code>
+                );
+              }
+              return (
+                <code className="bg-muted px-1.5 py-0.5 rounded text-xs font-mono text-foreground">
+                  {children}
+                </code>
+              );
+            },
+            table: ({ children }) => (
+              <div className="mb-4 overflow-x-auto rounded-md border border-border">
+                <table className="w-full text-sm border-collapse">
+                  {children}
+                </table>
+              </div>
+            ),
+            thead: ({ children }) => (
+              <thead className="bg-muted/50">{children}</thead>
+            ),
+            th: ({ children }) => (
+              <th className="px-4 py-2 text-left text-xs font-semibold text-foreground border-b border-border">
+                {children}
+              </th>
+            ),
+            td: ({ children }) => (
+              <td className="px-4 py-2 text-xs text-foreground/80 border-b border-border last:border-0">
+                {children}
+              </td>
+            ),
+            hr: () => <hr className="my-6 border-border" />,
+            a: ({ href, children }) => (
+              <a
+                href={href}
+                className="text-primary underline underline-offset-2 hover:text-primary/80 transition-colors"
+                target="_blank"
+                rel="noopener noreferrer"
+              >
+                {children}
+              </a>
+            ),
+            strong: ({ children }) => (
+              <strong className="font-semibold text-foreground">
+                {children}
+              </strong>
+            ),
+            em: ({ children }) => (
+              <em className="italic text-foreground/80">{children}</em>
+            ),
+          }}
+        >
+          {content.fullMarkdown}
+        </ReactMarkdown>
+      </div>
+    </div>
+  );
+}

frontend-web/src/open-canvas/components/chat/CanvasChatPanel.tsx

@@ -0,0 +1,205 @@
+import { Loader2, SendHorizonal, Sparkles, User, X } from "lucide-react";
+import { useRef, useState, type KeyboardEvent } from "react";
+
+import { Badge } from "@/components/ui/badge";
+import { Button } from "@/components/ui/button";
+import { Textarea } from "@/components/ui/textarea";
+
+import { useCanvasGraphContext } from "../../contexts/CanvasGraphContext";
+import { useCanvasSelection } from "../../hooks/useCanvasSelection";
+import { useCanvasStream } from "../../hooks/useCanvasStream";
+import { getCurrentArtifactContent, isCodeArtifact } from "../../utils/artifact";
+import {
+  buildMessageWithSelection,
+  hasActiveSelection,
+  resolveCodeSelection,
+} from "../../utils/selection";
+
+function ChatWelcome() {
+  return (
+    <div className="flex flex-col items-center justify-center h-full text-center px-6 space-y-3">
+      <div className="w-10 h-10 rounded-full bg-primary/10 flex items-center justify-center">
+        <Sparkles className="w-5 h-5 text-primary" />
+      </div>
+      <div className="space-y-1">
+        <p className="text-sm font-medium">开始创作</p>
+        <p className="text-xs text-muted-foreground leading-relaxed">
+          发送消息让 AI 帮你生成文档或代码，
+          <br />
+          或在右侧选择快速开始模板
+        </p>
+      </div>
+    </div>
+  );
+}
+
+export function CanvasChatPanel() {
+  const { messages, isStreaming, artifact } = useCanvasGraphContext();
+  const { sendMessage } = useCanvasStream();
+  const { selection, clearSelection } = useCanvasSelection();
+  const [input, setInput] = useState("");
+  const textareaRef = useRef<HTMLTextAreaElement>(null);
+
+  const hasMessages = messages.length > 0;
+  const hasSelection = hasActiveSelection(selection);
+
+  // Resolve selected code snippet when artifact is a code artifact
+  const currentContent = getCurrentArtifactContent(artifact);
+  const resolvedCode =
+    selection.codeSelection && currentContent && isCodeArtifact(currentContent)
+      ? resolveCodeSelection(
+          currentContent.code,
+          selection.codeSelection.startCharIndex,
+          selection.codeSelection.endCharIndex,
+        )
+      : undefined;
+
+  // Build a short preview for the selection badge
+  const selectionPreview = (() => {
+    if (selection.textSelection?.selectedText) {
+      const t = selection.textSelection.selectedText;
+      return t.length > 40 ? t.slice(0, 40) + "…" : t;
+    }
+    if (resolvedCode) {
+      return resolvedCode.length > 40
+        ? resolvedCode.slice(0, 40) + "…"
+        : resolvedCode;
+    }
+    return null;
+  })();
+
+  async function handleSend() {
+    const text = input.trim();
+    if (!text || isStreaming) return;
+    setInput("");
+
+    // Embed selection context into the message when something is selected
+    const finalText = hasSelection
+      ? buildMessageWithSelection(text, selection, resolvedCode)
+      : text;
+
+    clearSelection();
+    await sendMessage(finalText);
+  }
+
+  function handleKeyDown(e: KeyboardEvent<HTMLTextAreaElement>) {
+    if (e.key === "Enter" && !e.shiftKey) {
+      e.preventDefault();
+      void handleSend();
+    }
+  }
+
+  return (
+    <div className="h-full flex flex-col bg-background">
+      {/* Message list */}
+      <div className="flex-1 overflow-y-auto min-h-0">
+        {hasMessages ? (
+          <div className="p-4 space-y-4">
+            {messages.map((msg, i) => {
+              const isHuman = msg.type === "human";
+              const text =
+                typeof msg.content === "string"
+                  ? msg.content
+                  : JSON.stringify(msg.content);
+
+              return (
+                <div
+                  key={msg.id ?? i}
+                  className={`flex gap-2 ${isHuman ? "justify-end" : "justify-start"}`}
+                >
+                  {!isHuman && (
+                    <div className="w-6 h-6 rounded-full bg-primary/10 flex items-center justify-center shrink-0 mt-0.5">
+                      <Sparkles className="w-3 h-3 text-primary" />
+                    </div>
+                  )}
+                  <div
+                    className={`max-w-[80%] rounded-lg px-3 py-2 text-sm ${
+                      isHuman
+                        ? "bg-primary text-primary-foreground"
+                        : "bg-muted text-foreground"
+                    }`}
+                  >
+                    {text}
+                  </div>
+                  {isHuman && (
+                    <div className="w-6 h-6 rounded-full bg-muted flex items-center justify-center shrink-0 mt-0.5">
+                      <User className="w-3 h-3" />
+                    </div>
+                  )}
+                </div>
+              );
+            })}
+            {isStreaming && (
+              <div className="flex gap-2 justify-start">
+                <div className="w-6 h-6 rounded-full bg-primary/10 flex items-center justify-center shrink-0 mt-0.5">
+                  <Sparkles className="w-3 h-3 text-primary" />
+                </div>
+                <div className="bg-muted rounded-lg px-3 py-2">
+                  <Loader2 className="w-3 h-3 animate-spin text-muted-foreground" />
+                </div>
+              </div>
+            )}
+          </div>
+        ) : (
+          <ChatWelcome />
+        )}
+      </div>
+
+      {/* Selection badge */}
+      {hasSelection && selectionPreview && (
+        <div className="px-3 pt-2 shrink-0">
+          <Badge
+            variant="secondary"
+            className="flex items-center gap-1.5 max-w-full text-xs font-normal py-1 px-2 h-auto"
+          >
+            <span className="shrink-0 text-muted-foreground">
+              {selection.textSelection ? "选中文本:" : "选中代码:"}
+            </span>
+            <span className="truncate min-w-0 font-mono">
+              {selectionPreview}
+            </span>
+            <button
+              onClick={clearSelection}
+              className="shrink-0 ml-auto hover:text-foreground text-muted-foreground transition-colors"
+              aria-label="清除选区"
+            >
+              <X className="w-3 h-3" />
+            </button>
+          </Badge>
+        </div>
+      )}
+
+      {/* Input area */}
+      <div className="border-t p-3 shrink-0">
+        <div className="flex gap-2 items-end">
+          <Textarea
+            ref={textareaRef}
+            value={input}
+            onChange={(e) => setInput(e.target.value)}
+            onKeyDown={handleKeyDown}
+            placeholder={
+              hasSelection
+                ? "针对选中内容发出指令…"
+                : "发送消息以开始… (Enter 发送，Shift+Enter 换行)"
+            }
+            className="min-h-[40px] max-h-[160px] resize-none text-sm"
+            rows={1}
+            disabled={isStreaming}
+          />
+          <Button
+            size="icon"
+            className="h-9 w-9 shrink-0"
+            disabled={!input.trim() || isStreaming}
+            onClick={() => void handleSend()}
+          >
+            {isStreaming ? (
+              <Loader2 className="h-4 w-4 animate-spin" />
+            ) : (
+              <SendHorizonal className="h-4 w-4" />
+            )}
+          </Button>
+        </div>
+      </div>
+    </div>
+  );
+}

frontend-web/src/open-canvas/components/layout/CanvasHeader.tsx

@@ -0,0 +1,76 @@
+import { useNavigate } from "react-router-dom";
+import { ArrowLeft, Loader2, PanelLeftClose, PanelLeftOpen } from "lucide-react";
+
+import { Button } from "@/components/ui/button";
+import { Separator } from "@/components/ui/separator";
+import {
+  Tooltip,
+  TooltipContent,
+  TooltipTrigger,
+} from "@/components/ui/tooltip";
+
+import { useCanvasThreadContext } from "../../contexts/CanvasThreadContext";
+import { useCanvasGraphContext } from "../../contexts/CanvasGraphContext";
+import { useCanvasUIContext } from "../../contexts/CanvasUIContext";
+import { getCurrentArtifactContent } from "../../utils/artifact";
+
+export function CanvasHeader() {
+  const navigate = useNavigate();
+  const { threadId } = useCanvasThreadContext();
+  const { artifact, isStreaming } = useCanvasGraphContext();
+  const { isChatCollapsed, setIsChatCollapsed } = useCanvasUIContext();
+
+  const currentContent = getCurrentArtifactContent(artifact);
+  const title = currentContent?.title ?? "新 Canvas";
+
+  return (
+    <div className="h-11 border-b flex items-center px-3 gap-2 shrink-0 bg-background">
+      <Button
+        variant="ghost"
+        size="icon"
+        className="h-7 w-7 shrink-0"
+        onClick={() => navigate("/page/canvas")}
+        title="返回 Canvas 列表"
+      >
+        <ArrowLeft className="h-4 w-4" />
+      </Button>
+
+      <Separator orientation="vertical" className="h-4" />
+
+      <Tooltip>
+        <TooltipTrigger asChild>
+          <Button
+            variant="ghost"
+            size="icon"
+            className="h-7 w-7 shrink-0"
+            onClick={() => setIsChatCollapsed(!isChatCollapsed)}
+          >
+            {isChatCollapsed ? (
+              <PanelLeftOpen className="h-4 w-4" />
+            ) : (
+              <PanelLeftClose className="h-4 w-4" />
+            )}
+          </Button>
+        </TooltipTrigger>
+        <TooltipContent side="bottom">
+          {isChatCollapsed ? "展开聊天区" : "收起聊天区"}
+        </TooltipContent>
+      </Tooltip>
+
+      <Separator orientation="vertical" className="h-4" />
+
+      <div className="flex items-center gap-2 min-w-0 flex-1">
+        <span className="text-sm font-medium truncate">{title}</span>
+        {isStreaming && (
+          <Loader2 className="h-3.5 w-3.5 animate-spin text-muted-foreground shrink-0" />
+        )}
+      </div>
+
+      {threadId && (
+        <span className="text-[11px] text-muted-foreground font-mono hidden sm:block shrink-0 max-w-[120px] truncate">
+          {threadId.slice(0, 8)}
+        </span>
+      )}
+    </div>
+  );
+}

frontend-web/src/open-canvas/components/layout/CanvasResizableLayout.tsx

@@ -0,0 +1,58 @@
+import { useEffect, useRef } from "react";
+import type { GroupImperativeHandle } from "react-resizable-panels";
+
+import {
+  ResizableHandle,
+  ResizablePanel,
+  ResizablePanelGroup,
+} from "@/components/ui/resizable";
+
+import { useCanvasUIContext } from "../../contexts/CanvasUIContext";
+import { CanvasChatPanel } from "../chat/CanvasChatPanel";
+import { CanvasArtifactPanel } from "../artifact/CanvasArtifactPanel";
+
+const LAYOUT_COLLAPSED = { chat: 0, artifact: 100 };
+const LAYOUT_DEFAULT = { chat: 35, artifact: 65 };
+
+export function CanvasResizableLayout() {
+  const { isChatCollapsed } = useCanvasUIContext();
+  const layoutRef = useRef<GroupImperativeHandle>(null);
+
+  useEffect(() => {
+    layoutRef.current?.setLayout(
+      isChatCollapsed ? LAYOUT_COLLAPSED : LAYOUT_DEFAULT,
+    );
+  }, [isChatCollapsed]);
+
+  return (
+    <div className="flex-1 min-h-0 overflow-hidden">
+      <ResizablePanelGroup
+        orientation="horizontal"
+        groupRef={layoutRef}
+        className="h-full"
+      >
+        <ResizablePanel
+          id="chat"
+          defaultSize={35}
+          minSize={0}
+          collapsible
+          collapsedSize={0}
+          className="overflow-hidden"
+        >
+          <CanvasChatPanel />
+        </ResizablePanel>
+
+        <ResizableHandle withHandle />
+
+        <ResizablePanel
+          id="artifact"
+          defaultSize={65}
+          minSize={40}
+          className="overflow-hidden"
+        >
+          <CanvasArtifactPanel />
+        </ResizablePanel>
+      </ResizablePanelGroup>
+    </div>
+  );
+}

frontend-web/src/open-canvas/components/layout/CanvasShell.tsx

@@ -0,0 +1,43 @@
+import { useEffect } from "react";
+
+import { getCanvasThread } from "../../api/threads";
+import { useCanvasGraphContext } from "../../contexts/CanvasGraphContext";
+import { useCanvasThreadContext } from "../../contexts/CanvasThreadContext";
+import { CanvasHeader } from "./CanvasHeader";
+import { CanvasResizableLayout } from "./CanvasResizableLayout";
+
+export function CanvasShell() {
+  const { threadId } = useCanvasThreadContext();
+  const { setMessages, setArtifact } = useCanvasGraphContext();
+
+  // Load existing thread state when navigating to a saved thread
+  useEffect(() => {
+    if (!threadId) return;
+    let cancelled = false;
+
+    getCanvasThread(threadId)
+      .then((values) => {
+        if (cancelled || !values) return;
+        if (values.messages?.length) {
+          setMessages(values.messages);
+        }
+        if (values.artifact) {
+          setArtifact(values.artifact);
+        }
+      })
+      .catch((err) => {
+        console.error("[canvas] failed to load thread state:", err);
+      });
+
+    return () => {
+      cancelled = true;
+    };
+  }, [threadId, setMessages, setArtifact]);
+
+  return (
+    <div className="h-full flex flex-col overflow-hidden bg-background">
+      <CanvasHeader />
+      <CanvasResizableLayout />
+    </div>
+  );
+}

frontend-web/src/open-canvas/constants/index.ts

@@ -0,0 +1,43 @@
+import type { ProgrammingLanguageOptions } from "../types/artifact";
+import type { QuickAction } from "../types/quick-action";
+
+export const CANVAS_AGENT_ID = "canvas_agent";
+
+export const CANVAS_THREAD_METADATA = {
+  ui_mode: "canvas",
+  agent_id: CANVAS_AGENT_ID,
+} as const;
+
+export const PROGRAMMING_LANGUAGES: Array<{
+  language: ProgrammingLanguageOptions;
+  label: string;
+}> = [
+  { language: "typescript", label: "TypeScript" },
+  { language: "javascript", label: "JavaScript" },
+  { language: "python", label: "Python" },
+  { language: "html", label: "HTML" },
+  { language: "cpp", label: "C++" },
+  { language: "java", label: "Java" },
+  { language: "rust", label: "Rust" },
+  { language: "sql", label: "SQL" },
+  { language: "json", label: "JSON" },
+  { language: "php", label: "PHP" },
+  { language: "xml", label: "XML" },
+  { language: "clojure", label: "Clojure" },
+  { language: "csharp", label: "C#" },
+  { language: "other", label: "Other" },
+];
+
+export const QUICK_ACTIONS_TEXT: QuickAction[] = [
+  { id: "expand", label: "扩写", applicable_to: "text" },
+  { id: "shorten", label: "精简", applicable_to: "text" },
+  { id: "formalize", label: "改正式语气", applicable_to: "text" },
+  { id: "casualize", label: "改口语语气", applicable_to: "text" },
+];
+
+export const QUICK_ACTIONS_CODE: QuickAction[] = [
+  { id: "add_comments", label: "加注释", applicable_to: "code" },
+  { id: "add_logs", label: "加日志", applicable_to: "code" },
+  { id: "fix_bugs", label: "修复 Bug", applicable_to: "code" },
+  { id: "optimize_code", label: "优化代码", applicable_to: "code" },
+];

frontend-web/src/open-canvas/contexts/CanvasGraphContext.tsx

@@ -0,0 +1,72 @@
+import {
+  createContext,
+  useCallback,
+  useContext,
+  useState,
+  type ReactNode,
+} from "react";
+
+import type { CanvasArtifact } from "../types/artifact";
+import type { CanvasMessage } from "../types/thread";
+
+export interface CanvasGraphContextValue {
+  messages: CanvasMessage[];
+  artifact: CanvasArtifact | null;
+  isStreaming: boolean;
+  setMessages: (messages: CanvasMessage[]) => void;
+  /** Upsert a message by id — concatenates string content for streaming deltas. */
+  appendMessage: (msg: CanvasMessage) => void;
+  setArtifact: (artifact: CanvasArtifact | null) => void;
+  setIsStreaming: (v: boolean) => void;
+}
+
+const CanvasGraphContext = createContext<CanvasGraphContextValue | null>(null);
+
+export function CanvasGraphProvider({ children }: { children: ReactNode }) {
+  const [messages, setMessages] = useState<CanvasMessage[]>([]);
+  const [artifact, setArtifact] = useState<CanvasArtifact | null>(null);
+  const [isStreaming, setIsStreaming] = useState(false);
+
+  const appendMessage = useCallback((msg: CanvasMessage) => {
+    setMessages((prev) => {
+      if (!msg.id) return [...prev, msg];
+      const idx = prev.findIndex((m) => m.id === msg.id);
+      if (idx >= 0) {
+        const existing = prev[idx]!;
+        const existingText =
+          typeof existing.content === "string" ? existing.content : "";
+        const deltaText =
+          typeof msg.content === "string" ? msg.content : "";
+        const next = [...prev];
+        next[idx] = { ...existing, content: existingText + deltaText };
+        return next;
+      }
+      return [...prev, msg];
+    });
+  }, []);
+
+  return (
+    <CanvasGraphContext.Provider
+      value={{
+        messages,
+        artifact,
+        isStreaming,
+        setMessages,
+        appendMessage,
+        setArtifact,
+        setIsStreaming,
+      }}
+    >
+      {children}
+    </CanvasGraphContext.Provider>
+  );
+}
+
+export function useCanvasGraphContext() {
+  const ctx = useContext(CanvasGraphContext);
+  if (!ctx)
+    throw new Error(
+      "useCanvasGraphContext must be used within CanvasGraphProvider",
+    );
+  return ctx;
+}

frontend-web/src/open-canvas/contexts/CanvasThreadContext.tsx

@@ -0,0 +1,40 @@
+import { createContext, useContext, useState, type ReactNode } from "react";
+
+export interface CanvasThreadContextValue {
+  threadId: string | null;
+  modelName: string | null;
+  setThreadId: (id: string | null) => void;
+  setModelName: (name: string | null) => void;
+}
+
+const CanvasThreadContext = createContext<CanvasThreadContextValue | null>(null);
+
+export function CanvasThreadProvider({
+  children,
+  initialThreadId,
+}: {
+  children: ReactNode;
+  initialThreadId?: string | null;
+}) {
+  const [threadId, setThreadId] = useState<string | null>(
+    initialThreadId ?? null,
+  );
+  const [modelName, setModelName] = useState<string | null>(null);
+
+  return (
+    <CanvasThreadContext.Provider
+      value={{ threadId, setThreadId, modelName, setModelName }}
+    >
+      {children}
+    </CanvasThreadContext.Provider>
+  );
+}
+
+export function useCanvasThreadContext() {
+  const ctx = useContext(CanvasThreadContext);
+  if (!ctx)
+    throw new Error(
+      "useCanvasThreadContext must be used within CanvasThreadProvider",
+    );
+  return ctx;
+}

frontend-web/src/open-canvas/contexts/CanvasUIContext.tsx

@@ -0,0 +1,79 @@
+import {
+  createContext,
+  useCallback,
+  useContext,
+  useState,
+  type ReactNode,
+} from "react";
+
+import type {
+  CanvasCodeSelection,
+  CanvasSelectionState,
+  CanvasTextSelection,
+} from "../types/selection";
+
+export interface CanvasUIContextValue {
+  isChatCollapsed: boolean;
+  isEditing: boolean;
+  isWebSearchOpen: boolean;
+  selection: CanvasSelectionState;
+  setIsChatCollapsed: (v: boolean) => void;
+  setIsEditing: (v: boolean) => void;
+  setIsWebSearchOpen: (v: boolean) => void;
+  /** Set text selection; clears any existing code selection. */
+  setTextSelection: (s: CanvasTextSelection | null) => void;
+  /** Set code selection; clears any existing text selection. */
+  setCodeSelection: (s: CanvasCodeSelection | null) => void;
+  clearSelection: () => void;
+}
+
+const EMPTY_SELECTION: CanvasSelectionState = {
+  textSelection: null,
+  codeSelection: null,
+};
+
+const CanvasUIContext = createContext<CanvasUIContextValue | null>(null);
+
+export function CanvasUIProvider({ children }: { children: ReactNode }) {
+  const [isChatCollapsed, setIsChatCollapsed] = useState(false);
+  const [isEditing, setIsEditing] = useState(false);
+  const [isWebSearchOpen, setIsWebSearchOpen] = useState(false);
+  const [selection, setSelection] =
+    useState<CanvasSelectionState>(EMPTY_SELECTION);
+
+  const setTextSelection = useCallback((s: CanvasTextSelection | null) => {
+    setSelection({ textSelection: s, codeSelection: null });
+  }, []);
+
+  const setCodeSelection = useCallback((s: CanvasCodeSelection | null) => {
+    setSelection({ textSelection: null, codeSelection: s });
+  }, []);
+
+  return (
+    <CanvasUIContext.Provider
+      value={{
+        isChatCollapsed,
+        isEditing,
+        isWebSearchOpen,
+        selection,
+        setIsChatCollapsed,
+        setIsEditing,
+        setIsWebSearchOpen,
+        setTextSelection,
+        setCodeSelection,
+        clearSelection: () => setSelection(EMPTY_SELECTION),
+      }}
+    >
+      {children}
+    </CanvasUIContext.Provider>
+  );
+}
+
+export function useCanvasUIContext() {
+  const ctx = useContext(CanvasUIContext);
+  if (!ctx)
+    throw new Error(
+      "useCanvasUIContext must be used within CanvasUIProvider",
+    );
+  return ctx;
+}

frontend-web/src/open-canvas/hooks/useCanvasArtifact.ts

@@ -0,0 +1,2 @@
+// Phase 6-7: artifact version management helpers
+export {};

frontend-web/src/open-canvas/hooks/useCanvasQuickActions.ts

@@ -0,0 +1,2 @@
+// Phase 9: trigger quick actions and write quick_action_id to run input
+export {};

frontend-web/src/open-canvas/hooks/useCanvasSelection.ts

@@ -0,0 +1,43 @@
+import { useCallback } from "react";
+
+import { useCanvasUIContext } from "../contexts/CanvasUIContext";
+import { captureTextSelection } from "../utils/selection";
+
+export function useCanvasSelection() {
+  const { selection, setTextSelection, setCodeSelection, clearSelection } =
+    useCanvasUIContext();
+
+  /**
+   * Call from a text renderer's onMouseUp handler.
+   * Reads window.getSelection() and stores the result.
+   */
+  const handleTextPointerUp = useCallback(
+    (fullMarkdown: string) => {
+      const captured = captureTextSelection(fullMarkdown);
+      setTextSelection(captured);
+    },
+    [setTextSelection],
+  );
+
+  /**
+   * Call from CodeMirror's onUpdate/onStatistics handler.
+   * Pass the selection range (from/to char indices).
+   */
+  const handleCodeSelectionChange = useCallback(
+    (from: number, to: number) => {
+      if (from === to) {
+        setCodeSelection(null);
+      } else {
+        setCodeSelection({ startCharIndex: from, endCharIndex: to });
+      }
+    },
+    [setCodeSelection],
+  );
+
+  return {
+    selection,
+    handleTextPointerUp,
+    handleCodeSelectionChange,
+    clearSelection,
+  };
+}

frontend-web/src/open-canvas/hooks/useCanvasStream.ts

@@ -0,0 +1,88 @@
+import { useCallback, useRef } from "react";
+import { useNavigate } from "react-router-dom";
+
+import { streamCanvasRun } from "../api/runs";
+import type { CanvasRunInput } from "../api/runs";
+import { createCanvasThread } from "../api/threads";
+import { useCanvasGraphContext } from "../contexts/CanvasGraphContext";
+import { useCanvasThreadContext } from "../contexts/CanvasThreadContext";
+import type { CanvasMessage } from "../types/thread";
+
+export function useCanvasStream() {
+  const navigate = useNavigate();
+  const { threadId, setThreadId, modelName } = useCanvasThreadContext();
+  const { messages, setMessages, appendMessage, setArtifact, setIsStreaming } =
+    useCanvasGraphContext();
+
+  // Ref so callbacks inside streamCanvasRun always see the latest messages
+  // without adding `messages` to useCallback's dep array (avoids re-creation
+  // on every message append during streaming).
+  const messagesRef = useRef(messages);
+  messagesRef.current = messages;
+
+  const sendMessage = useCallback(
+    async (
+      text: string,
+      extra?: Partial<Omit<CanvasRunInput, "messages">>,
+    ) => {
+      // 1. Ensure we have a thread
+      let activeThreadId = threadId;
+      if (!activeThreadId) {
+        activeThreadId = await createCanvasThread(
+          modelName ? { model_name: modelName } : undefined,
+        );
+        setThreadId(activeThreadId);
+        navigate(`/page/canvas/${activeThreadId}`, { replace: true });
+      }
+
+      // 2. Optimistic human message
+      const humanMsg: CanvasMessage = {
+        id: `human-${Date.now()}`,
+        type: "human",
+        content: text,
+      };
+      setMessages([...messagesRef.current, humanMsg]);
+      setIsStreaming(true);
+
+      // 3. Build run input
+      const input: CanvasRunInput = {
+        messages: [{ type: "human", content: text }],
+        ...extra,
+      };
+
+      // 4. Stream
+      await streamCanvasRun(activeThreadId, input, {
+        onMessage(msg) {
+          // Only surface AI text replies; skip tool messages
+          if (msg.type === "ai") {
+            appendMessage(msg);
+          }
+        },
+        onArtifact(artifact) {
+          setArtifact(artifact);
+        },
+        onDone() {
+          setIsStreaming(false);
+        },
+        onError(err) {
+          console.error("[canvas] stream error:", err);
+          setIsStreaming(false);
+        },
+      });
+    },
+    // messagesRef replaces direct `messages` dep — intentional
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+    [
+      threadId,
+      modelName,
+      setThreadId,
+      navigate,
+      appendMessage,
+      setMessages,
+      setArtifact,
+      setIsStreaming,
+    ],
+  );
+
+  return { sendMessage };
+}

frontend-web/src/open-canvas/hooks/useCanvasThread.ts

@@ -0,0 +1 @@
+export { useCanvasThreadContext as useCanvasThread } from "../contexts/CanvasThreadContext";

frontend-web/src/open-canvas/pages/CanvasHomePage.tsx

@@ -0,0 +1,76 @@
+import { useNavigate } from "react-router-dom";
+import { v4 as uuidv4 } from "uuid";
+import { FileText, Code2, Sparkles } from "lucide-react";
+
+import { Button } from "@/components/ui/button";
+
+const QUICK_START_ITEMS = [
+  {
+    type: "text" as const,
+    icon: FileText,
+    title: "新建文本文档",
+    description: "撰写和编辑 Markdown 文档，AI 实时协作修改",
+  },
+  {
+    type: "code" as const,
+    icon: Code2,
+    title: "新建代码",
+    description: "编写和重构多语言代码，AI 辅助生成与优化",
+  },
+];
+
+export default function CanvasHomePage() {
+  const navigate = useNavigate();
+
+  function handleQuickStart(type: "text" | "code") {
+    const threadId = uuidv4();
+    navigate(`${threadId}?type=${type}`);
+  }
+
+  return (
+    <div className="h-full flex flex-col items-center justify-center bg-background px-6">
+      <div className="w-full max-w-xl space-y-10">
+        <div className="text-center space-y-3">
+          <div className="inline-flex items-center justify-center w-12 h-12 rounded-xl bg-primary/10 mb-2">
+            <Sparkles className="w-6 h-6 text-primary" />
+          </div>
+          <h1 className="text-3xl font-bold tracking-tight">Canvas 模式</h1>
+          <p className="text-muted-foreground text-base leading-relaxed">
+            在左侧聊天区与 AI 协作，右侧实时生成和编辑文档或代码
+          </p>
+        </div>
+
+        <div className="grid grid-cols-2 gap-4">
+          {QUICK_START_ITEMS.map(({ type, icon: Icon, title, description }) => (
+            <button
+              key={type}
+              onClick={() => handleQuickStart(type)}
+              className="group flex flex-col gap-3 rounded-xl border bg-card p-5 text-left transition-all hover:border-primary/50 hover:shadow-md hover:bg-accent/30 focus:outline-none focus-visible:ring-2 focus-visible:ring-ring"
+            >
+              <div className="flex items-center justify-center w-9 h-9 rounded-lg bg-muted group-hover:bg-primary/10 transition-colors">
+                <Icon className="w-4 h-4 text-muted-foreground group-hover:text-primary transition-colors" />
+              </div>
+              <div className="space-y-1">
+                <p className="font-medium text-sm">{title}</p>
+                <p className="text-xs text-muted-foreground leading-relaxed">
+                  {description}
+                </p>
+              </div>
+            </button>
+          ))}
+        </div>
+
+        <div className="text-center">
+          <Button
+            variant="ghost"
+            size="sm"
+            className="text-muted-foreground text-xs"
+            onClick={() => navigate(uuidv4())}
+          >
+            或直接开始空白 Canvas
+          </Button>
+        </div>
+      </div>
+    </div>
+  );
+}

frontend-web/src/open-canvas/pages/CanvasThreadPage.tsx

@@ -0,0 +1,20 @@
+import { useParams } from "react-router-dom";
+
+import { CanvasThreadProvider } from "../contexts/CanvasThreadContext";
+import { CanvasGraphProvider } from "../contexts/CanvasGraphContext";
+import { CanvasUIProvider } from "../contexts/CanvasUIContext";
+import { CanvasShell } from "../components/layout/CanvasShell";
+
+export default function CanvasThreadPage() {
+  const { thread_id } = useParams<{ thread_id: string }>();
+
+  return (
+    <CanvasThreadProvider initialThreadId={thread_id}>
+      <CanvasGraphProvider>
+        <CanvasUIProvider>
+          <CanvasShell />
+        </CanvasUIProvider>
+      </CanvasGraphProvider>
+    </CanvasThreadProvider>
+  );
+}

frontend-web/src/open-canvas/routes/OpenCanvasRoutes.tsx

@@ -0,0 +1,13 @@
+import { Route, Routes } from "react-router-dom";
+
+import CanvasHomePage from "../pages/CanvasHomePage";
+import CanvasThreadPage from "../pages/CanvasThreadPage";
+
+export default function OpenCanvasRoutes() {
+  return (
+    <Routes>
+      <Route index element={<CanvasHomePage />} />
+      <Route path=":thread_id" element={<CanvasThreadPage />} />
+    </Routes>
+  );
+}

frontend-web/src/open-canvas/types/artifact.ts

@@ -0,0 +1,39 @@
+export type ProgrammingLanguageOptions =
+  | "typescript"
+  | "javascript"
+  | "cpp"
+  | "java"
+  | "php"
+  | "python"
+  | "html"
+  | "sql"
+  | "json"
+  | "rust"
+  | "xml"
+  | "clojure"
+  | "csharp"
+  | "other";
+
+export type ArtifactType = "code" | "text";
+
+export type CanvasArtifactText = {
+  index: number;
+  type: "text";
+  title: string;
+  fullMarkdown: string;
+};
+
+export type CanvasArtifactCode = {
+  index: number;
+  type: "code";
+  title: string;
+  language: ProgrammingLanguageOptions;
+  code: string;
+};
+
+export type CanvasArtifactContent = CanvasArtifactText | CanvasArtifactCode;
+
+export type CanvasArtifact = {
+  currentIndex: number;
+  contents: CanvasArtifactContent[];
+};

frontend-web/src/open-canvas/types/model.ts

@@ -0,0 +1,15 @@
+export type CanvasModel = {
+  name: string;
+  display_name: string;
+  provider?: string;
+  is_local?: boolean;
+  supports_vision?: boolean;
+  supports_thinking?: boolean;
+  supports_reasoning_effort?: boolean;
+  supports_tool_calling?: boolean;
+  supports_canvas_generation?: boolean;
+  supports_canvas_rewrite?: boolean;
+  supports_canvas_code_edit?: boolean;
+  supports_streaming_text?: boolean;
+  supports_streaming_tool_calls?: boolean;
+};

frontend-web/src/open-canvas/types/quick-action.ts

@@ -0,0 +1,20 @@
+export type QuickActionApplicableTo = "text" | "code" | "both";
+
+export type QuickAction = {
+  id: string;
+  label: string;
+  applicable_to: QuickActionApplicableTo;
+  prompt_template?: string;
+};
+
+export type QuickActionId =
+  | "expand"
+  | "shorten"
+  | "formalize"
+  | "casualize"
+  | "add_comments"
+  | "add_logs"
+  | "fix_bugs"
+  | "optimize_code"
+  | "port_language"
+  | string;

frontend-web/src/open-canvas/types/selection.ts

@@ -0,0 +1,15 @@
+export type CanvasTextSelection = {
+  fullMarkdown: string;
+  markdownBlock: string;
+  selectedText: string;
+};
+
+export type CanvasCodeSelection = {
+  startCharIndex: number;
+  endCharIndex: number;
+};
+
+export type CanvasSelectionState = {
+  textSelection: CanvasTextSelection | null;
+  codeSelection: CanvasCodeSelection | null;
+};

frontend-web/src/open-canvas/types/thread.ts

@@ -0,0 +1,22 @@
+import type { CanvasArtifact } from "./artifact";
+
+export type CanvasMessage = {
+  id?: string;
+  type: string;
+  content: string | unknown[];
+  additional_kwargs?: Record<string, unknown>;
+};
+
+export type CanvasThreadValues = {
+  title?: string;
+  messages?: CanvasMessage[];
+  artifact?: CanvasArtifact;
+  web_search_results?: unknown[];
+  todos?: unknown[];
+};
+
+export type CanvasThreadMetadata = {
+  ui_mode: "canvas";
+  agent_id: "canvas_agent";
+  model_name?: string;
+};

frontend-web/src/open-canvas/utils/artifact.ts

@@ -0,0 +1,84 @@
+import type {
+  CanvasArtifact,
+  CanvasArtifactContent,
+  CanvasArtifactText,
+  CanvasArtifactCode,
+  ProgrammingLanguageOptions,
+} from "../types/artifact";
+
+export function getCurrentArtifactContent(
+  artifact: CanvasArtifact | null,
+): CanvasArtifactContent | null {
+  if (!artifact || artifact.contents.length === 0) return null;
+  return (
+    artifact.contents.find((c) => c.index === artifact.currentIndex) ??
+    artifact.contents[artifact.contents.length - 1]
+  );
+}
+
+export function isTextArtifact(
+  content: CanvasArtifactContent,
+): content is CanvasArtifactText {
+  return content.type === "text";
+}
+
+export function isCodeArtifact(
+  content: CanvasArtifactContent,
+): content is CanvasArtifactCode {
+  return content.type === "code";
+}
+
+export function appendArtifactVersion(
+  artifact: CanvasArtifact,
+  content: Omit<CanvasArtifactContent, "index">,
+): CanvasArtifact {
+  const nextIndex = artifact.contents.length + 1;
+  const newContent = { ...content, index: nextIndex } as CanvasArtifactContent;
+  return {
+    currentIndex: nextIndex,
+    contents: [...artifact.contents, newContent],
+  };
+}
+
+export function setCurrentArtifactIndex(
+  artifact: CanvasArtifact,
+  index: number,
+): CanvasArtifact {
+  return { ...artifact, currentIndex: index };
+}
+
+export function createDraftArtifact(
+  type: "text" | "code",
+  options?: {
+    title?: string;
+    content?: string;
+    language?: ProgrammingLanguageOptions;
+  },
+): CanvasArtifact {
+  const { title, content = "", language = "python" } = options ?? {};
+  if (type === "text") {
+    return {
+      currentIndex: 1,
+      contents: [
+        {
+          index: 1,
+          type: "text",
+          title: title ?? "未命名文档",
+          fullMarkdown: content,
+        },
+      ],
+    };
+  }
+  return {
+    currentIndex: 1,
+    contents: [
+      {
+        index: 1,
+        type: "code",
+        title: title ?? "未命名代码",
+        language,
+        code: content,
+      },
+    ],
+  };
+}

frontend-web/src/open-canvas/utils/quick-actions.ts

@@ -0,0 +1,2 @@
+// Phase 9: map quick action ids to run inputs
+export {};

frontend-web/src/open-canvas/utils/selection.ts

@@ -0,0 +1,98 @@
+import type {
+  CanvasSelectionState,
+  CanvasTextSelection,
+} from "../types/selection";
+
+export function hasActiveSelection(selection: CanvasSelectionState): boolean {
+  return selection.textSelection !== null || selection.codeSelection !== null;
+}
+
+/**
+ * Find the nearest line-level block in markdown that contains selectedText.
+ * Falls back to the selectedText itself when no clean boundary is found.
+ */
+function findMarkdownBlock(fullMarkdown: string, selectedText: string): string {
+  const idx = fullMarkdown.indexOf(selectedText);
+  if (idx === -1) return selectedText;
+
+  let blockStart = idx;
+  while (blockStart > 0 && fullMarkdown[blockStart - 1] !== "\n") {
+    blockStart--;
+  }
+
+  let blockEnd = idx + selectedText.length;
+  while (blockEnd < fullMarkdown.length && fullMarkdown[blockEnd] !== "\n") {
+    blockEnd++;
+  }
+
+  return fullMarkdown.slice(blockStart, blockEnd).trim();
+}
+
+/**
+ * Read the browser selection and map it to a CanvasTextSelection.
+ * Returns null when nothing meaningful is selected.
+ */
+export function captureTextSelection(
+  fullMarkdown: string,
+): CanvasTextSelection | null {
+  const sel = window.getSelection();
+  if (!sel || sel.isCollapsed) return null;
+
+  const selectedText = sel.toString().trim();
+  if (!selectedText) return null;
+
+  return {
+    fullMarkdown,
+    markdownBlock: findMarkdownBlock(fullMarkdown, selectedText),
+    selectedText,
+  };
+}
+
+/**
+ * Extract the code snippet from a full code string given char indices.
+ */
+export function resolveCodeSelection(
+  code: string,
+  start: number,
+  end: number,
+): string {
+  return code.slice(start, end).trim();
+}
+
+/**
+ * Build the human message with embedded selection context so the canvas_agent
+ * knows exactly which portion to rewrite.
+ */
+export function buildMessageWithSelection(
+  userText: string,
+  selection: CanvasSelectionState,
+  resolvedCode?: string,
+): string {
+  const { textSelection, codeSelection } = selection;
+
+  if (textSelection?.selectedText) {
+    return [
+      "请针对以下选中的文本内容进行操作：",
+      "",
+      "<selection>",
+      textSelection.selectedText,
+      "</selection>",
+      "",
+      `用户指令：${userText}`,
+    ].join("\n");
+  }
+
+  if (codeSelection && resolvedCode) {
+    return [
+      "请针对以下选中的代码片段进行操作：",
+      "",
+      "<selection>",
+      resolvedCode,
+      "</selection>",
+      "",
+      `用户指令：${userText}`,
+    ].join("\n");
+  }
+
+  return userText;
+}

frontend-web/src/open-canvas/utils/stream.ts

@@ -0,0 +1,2 @@
+// Phase 6: parse LangGraph stream events into messages and artifact updates
+export {};

frontend-web/src/open-canvas/utils/thread.ts

@@ -0,0 +1,2 @@
+// Phase 5: thread creation, metadata tagging, and state recovery helpers
+export {};

frontend-web/src/pages/PageRoutes.tsx

@@ -6,6 +6,7 @@ import { PageSidebar } from "@/components/page-sidebar";
 import WorkspaceRoutes from "./WorkspaceRoutes";
 import StrategyRoutes from "./StrategyRoutes";
 import Header from "@/strategy-components/Header";
+import OpenCanvasRoutes from "@/open-canvas/routes/OpenCanvasRoutes";
 
 // 设为 true 时隐藏侧边栏（开发中，暂未完成）
 const SIDEBAR_ENABLED = false;
@@ -41,6 +42,7 @@ function PageLayout() {
               }
             />
             <Route path="strategy/*" element={<StrategyRoutes />} />
+            <Route path="canvas/*" element={<OpenCanvasRoutes />} />
           </Routes>
         </main>
       </div>

offline-backend-20260512/backend/langgraph.json

@@ -6,7 +6,8 @@
   ],
   "env": ".env",
   "graphs": {
-    "lead_agent": "deerflow.agents:make_lead_agent"
+    "lead_agent": "deerflow.agents:make_lead_agent",
+    "canvas_agent": "deerflow.agents.canvas_agent:make_canvas_agent"
   },
   "auth": {
     "path": "./app/gateway/langgraph_auth.py:auth"

offline-backend-20260512/backend/packages/harness/deerflow/agents/canvas_agent/__init__.py

@@ -0,0 +1,3 @@
+from deerflow.agents.canvas_agent.agent import make_canvas_agent
+
+__all__ = ["make_canvas_agent"]

offline-backend-20260512/backend/packages/harness/deerflow/agents/canvas_agent/agent.py

@@ -0,0 +1,68 @@
+from __future__ import annotations
+
+import logging
+
+from langchain.agents import create_agent
+from langchain_core.runnables import RunnableConfig
+
+from deerflow.agents.canvas_agent.prompt import CANVAS_SYSTEM_PROMPT
+from deerflow.agents.canvas_agent.tools import update_artifact_tool
+from deerflow.agents.middlewares.clarification_middleware import ClarificationMiddleware
+from deerflow.agents.middlewares.dangling_tool_call_middleware import DanglingToolCallMiddleware
+from deerflow.agents.middlewares.loop_detection_middleware import LoopDetectionMiddleware
+from deerflow.agents.middlewares.title_middleware import TitleMiddleware
+from deerflow.agents.middlewares.tool_error_handling_middleware import ToolErrorHandlingMiddleware
+from deerflow.agents.thread_state import ThreadState
+from deerflow.config.app_config import get_app_config
+from deerflow.models import create_chat_model
+from deerflow.tools.builtins import ask_clarification_tool
+
+logger = logging.getLogger(__name__)
+
+
+def _get_runtime_config(config: RunnableConfig) -> dict:
+    cfg = dict(config.get("configurable", {}) or {})
+    context = config.get("context", {}) or {}
+    if isinstance(context, dict):
+        cfg.update(context)
+    return cfg
+
+
+def make_canvas_agent(config: RunnableConfig):
+    """LangGraph graph factory for canvas mode; signature compatible with LangGraph Server."""
+    app_config = get_app_config()
+    cfg = _get_runtime_config(config)
+
+    requested_model = cfg.get("model_name") or cfg.get("model")
+    if requested_model and app_config.get_model_config(requested_model):
+        model_name = requested_model
+    else:
+        if requested_model:
+            logger.warning("Canvas agent: model '%s' not found; falling back to default.", requested_model)
+        model_name = app_config.models[0].name if app_config.models else None
+
+    if model_name is None:
+        raise ValueError("No chat models configured. Please add at least one model in config.yaml.")
+
+    thinking_enabled = cfg.get("thinking_enabled", False)
+    model_config = app_config.get_model_config(model_name)
+    if thinking_enabled and model_config and not model_config.supports_thinking:
+        thinking_enabled = False
+
+    logger.info("Create CanvasAgent -> model_name: %s, thinking_enabled: %s", model_name, thinking_enabled)
+
+    middlewares = [
+        DanglingToolCallMiddleware(),
+        ToolErrorHandlingMiddleware(),
+        TitleMiddleware(app_config=app_config),
+        LoopDetectionMiddleware(),
+        ClarificationMiddleware(),
+    ]
+
+    return create_agent(
+        model=create_chat_model(name=model_name, thinking_enabled=thinking_enabled, app_config=app_config),
+        tools=[update_artifact_tool, ask_clarification_tool],
+        middleware=middlewares,
+        system_prompt=CANVAS_SYSTEM_PROMPT,
+        state_schema=ThreadState,
+    )

offline-backend-20260512/backend/packages/harness/deerflow/agents/canvas_agent/prompt.py

@@ -0,0 +1,40 @@
+CANVAS_SYSTEM_PROMPT = """You are a Canvas AI assistant that helps users create and edit documents and code.
+
+<canvas_behavior>
+You work with an **artifact** — a document or code file shown in the canvas panel on the right.
+ALWAYS call `update_artifact` to save your work. Never embed the artifact content in your chat response.
+
+Rules:
+- On every request that creates or changes the artifact, call `update_artifact` ONCE with the COMPLETE updated content.
+- In your text reply, describe what you did in 1–2 sentences.
+- If the user is only asking a question (no edit needed), answer in text — skip the tool call.
+</canvas_behavior>
+
+<artifact_context>
+The current artifact state is injected into your context. When editing, build on the existing content exactly.
+When creating from scratch, produce a complete, high-quality artifact in one shot.
+</artifact_context>
+
+<selection_rewrite>
+When the user's message contains a <selection> block, you MUST:
+1. Identify the exact selection in the current artifact content.
+2. Rewrite ONLY that selection according to the user's instruction.
+3. Keep the rest of the artifact exactly unchanged.
+4. Call update_artifact with the complete artifact where the selection has been replaced.
+
+Example: if the artifact is "A B C" and the selection is "B" with instruction "make it bold",
+produce "A **B** C" — not a new document.
+</selection_rewrite>
+
+<quick_actions>
+When the user triggers a quick action, apply it to the full artifact unless specific highlighted text is provided:
+- expand: Add depth and detail while preserving structure
+- shorten: Condense to the essential points
+- formalize: Rewrite in professional, formal language
+- casualize: Rewrite in friendly, conversational language
+- add_comments: Add clear, helpful code comments
+- add_logs: Add appropriate logging statements
+- fix_bugs: Identify and fix all bugs in the code
+- optimize_code: Improve performance and readability
+</quick_actions>
+"""

offline-backend-20260512/backend/packages/harness/deerflow/agents/canvas_agent/tools.py

@@ -0,0 +1,65 @@
+from __future__ import annotations
+
+from typing import Annotated, Literal
+
+from langchain.tools import InjectedToolCallId, ToolRuntime, tool
+from langchain_core.messages import ToolMessage
+from langgraph.types import Command
+from langgraph.typing import ContextT
+
+from deerflow.agents.thread_state import CanvasArtifact, CanvasArtifactCode, CanvasArtifactText, ThreadState
+
+
+@tool("update_artifact", parse_docstring=True)
+def update_artifact_tool(
+    runtime: ToolRuntime[ContextT, ThreadState],
+    tool_call_id: Annotated[str, InjectedToolCallId],
+    type: Literal["text", "code"],
+    title: str,
+    content: str,
+    language: str = "other",
+) -> Command:
+    """Create or update the canvas artifact. Always call this to persist your work.
+
+    Args:
+        type: Artifact type — "text" for markdown documents, "code" for source code.
+        title: Human-readable title of the artifact.
+        content: Full artifact content: markdown text or complete source code.
+        language: Programming language (for code type only, e.g. "python", "typescript"). Ignored for text.
+    """
+    current: CanvasArtifact | None = (runtime.state or {}).get("artifact") if runtime.state else None
+
+    if current is not None:
+        existing_contents = list(current.get("contents", []))
+        new_index = current.get("currentIndex", len(existing_contents)) + 1
+    else:
+        existing_contents = []
+        new_index = 1
+
+    if type == "text":
+        new_entry: CanvasArtifactText | CanvasArtifactCode = CanvasArtifactText(
+            index=new_index,
+            type="text",
+            title=title,
+            fullMarkdown=content,
+        )
+    else:
+        new_entry = CanvasArtifactCode(
+            index=new_index,
+            type="code",
+            title=title,
+            language=language,
+            code=content,
+        )
+
+    updated: CanvasArtifact = {
+        "currentIndex": new_index,
+        "contents": existing_contents + [new_entry],
+    }
+
+    return Command(
+        update={
+            "artifact": updated,
+            "messages": [ToolMessage("Artifact updated.", tool_call_id=tool_call_id)],
+        }
+    )

offline-backend-20260512/backend/packages/harness/deerflow/agents/thread_state.py

@@ -1,4 +1,4 @@
-from typing import Annotated, NotRequired, TypedDict
+from typing import Annotated, Literal, NotRequired, Optional, TypedDict
 
 from langchain.agents import AgentState
 
@@ -18,6 +18,26 @@ class ViewedImageData(TypedDict):
     mime_type: str
 
 
+class CanvasArtifactText(TypedDict):
+    index: int
+    type: Literal["text"]
+    title: str
+    fullMarkdown: str
+
+
+class CanvasArtifactCode(TypedDict):
+    index: int
+    type: Literal["code"]
+    title: str
+    language: str
+    code: str
+
+
+class CanvasArtifact(TypedDict):
+    currentIndex: int
+    contents: list[CanvasArtifactText | CanvasArtifactCode]
+
+
 def merge_artifacts(existing: list[str] | None, new: list[str] | None) -> list[str]:
     """Reducer for artifacts list - merges and deduplicates artifacts."""
     if existing is None:
@@ -53,3 +73,11 @@ class ThreadState(AgentState):
     todos: NotRequired[list | None]
     uploaded_files: NotRequired[list[dict] | None]
     viewed_images: Annotated[dict[str, ViewedImageData], merge_viewed_images]  # image_path -> {base64, mime_type}
+    # Canvas fields (coexist with artifacts: list[str] which tracks file outputs)
+    artifact: NotRequired[Optional[CanvasArtifact]]
+    highlighted_text: NotRequired[Optional[str]]
+    highlighted_code: NotRequired[Optional[str]]
+    canvas_mode: NotRequired[Optional[Literal["text", "code"]]]
+    quick_action_id: NotRequired[Optional[str]]
+    web_search_enabled: NotRequired[bool]
+    web_search_results: NotRequired[Optional[list[dict]]]