feat: 新增写作画布系统

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

@@ -8,6 +8,7 @@ import {
   EyeIcon,
   LoaderIcon,
   PackageIcon,
+  SaveIcon,
   SquareArrowOutUpRightIcon,
   XIcon,
 } from "lucide-react";
@@ -37,7 +38,10 @@ import {
   downloadArtifactFile,
   openArtifactInNewTab,
 } from "@/core/artifacts/download";
-import { useArtifactContent } from "@/core/artifacts/hooks";
+import {
+  useArtifactContent,
+  useUpdateArtifactContent,
+} from "@/core/artifacts/hooks";
 import { urlOfArtifact } from "@/core/artifacts/utils";
 import { useI18n } from "@/core/i18n/hooks";
 import { installSkill } from "@/core/skills/api";
@@ -113,13 +117,18 @@ export function ArtifactFileDetail({
   const isSupportPreview = useMemo(() => {
     return language === "html" || language === "markdown";
   }, [language]);
-  const { content } = useArtifactContent({
+  const { content, isApplyingEdit } = useArtifactContent({
     threadId,
     filepath: filepathFromProps,
     enabled: isCodeFile && !isWriteFile,
   });
 
-  const displayContent = content ?? "";
+  const canEditArtifact =
+    language === "markdown" && !isWriteFile && !isSkillFile && !isMock;
+  const [draftContent, setDraftContent] = useState("");
+  const [hasLocalEdits, setHasLocalEdits] = useState(false);
+  const updateArtifact = useUpdateArtifactContent();
+  const displayContent = canEditArtifact ? draftContent : (content ?? "");
   const isHtmlStreaming = language === "html" && thread.isLoading;
   const hasMultipleArtifacts = (artifacts?.length ?? 0) > 1;
   const fileTypeLabel = useMemo(() => {
@@ -142,6 +151,18 @@ export function ArtifactFileDetail({
   const artifactContentRef = useRef<HTMLDivElement | null>(null);
   const resumeButtonTimeoutRef = useRef<number | null>(null);
 
+  useEffect(() => {
+    setDraftContent(content ?? "");
+    setHasLocalEdits(false);
+  }, [filepathFromProps]);
+
+  useEffect(() => {
+    if (!canEditArtifact || hasLocalEdits) {
+      return;
+    }
+    setDraftContent(content ?? "");
+  }, [canEditArtifact, content, hasLocalEdits]);
+
   useEffect(() => {
     setAllowAutoViewSwitch(true);
     setAutoScrollEnabled(true);
@@ -330,6 +351,32 @@ export function ArtifactFileDetail({
     }
   }, [threadId, filepath, isInstalling]);
 
+  const handleSaveArtifact = useCallback(async () => {
+    if (!canEditArtifact || updateArtifact.isPending) {
+      return;
+    }
+    try {
+      await updateArtifact.mutateAsync({
+        filepath,
+        threadId,
+        isMock,
+        content: draftContent,
+      });
+      setHasLocalEdits(false);
+      toast.success("Markdown 已保存");
+    } catch (error) {
+      console.error("Failed to save artifact:", error);
+      toast.error(error instanceof Error ? error.message : "Markdown 保存失败");
+    }
+  }, [
+    canEditArtifact,
+    draftContent,
+    filepath,
+    isMock,
+    threadId,
+    updateArtifact,
+  ]);
+
   return (
     <Artifact className={cn(className)}>
       <ArtifactHeader className="grid grid-cols-[minmax(0,1fr)_auto_minmax(0,1fr)] items-center gap-3 px-4 py-3">
@@ -407,6 +454,15 @@ export function ArtifactFileDetail({
         </div>
         <div className="flex items-center justify-end gap-2">
           <ArtifactActions className="bg-muted/45 rounded-full border border-black/6 p-1 dark:border-white/8">
+            {canEditArtifact && (
+              <ArtifactAction
+                icon={updateArtifact.isPending ? LoaderIcon : SaveIcon}
+                label="保存 Markdown"
+                tooltip={hasLocalEdits ? "保存 Markdown 修改" : "Markdown 已保存"}
+                disabled={!hasLocalEdits || updateArtifact.isPending}
+                onClick={handleSaveArtifact}
+              />
+            )}
             {!isWriteFile && filepath.endsWith(".skill") && (
               <Tooltip content={t.toolCalls.skillInstallTooltip}>
                 <ArtifactAction
@@ -499,6 +555,12 @@ export function ArtifactFileDetail({
         className="relative p-0"
         onWheelCapture={handlePauseAutoScroll}
       >
+        {isApplyingEdit && (
+          <div className="absolute right-4 bottom-4 z-20 inline-flex items-center gap-2 rounded-full border border-[#d8b878] bg-[#fff3cf]/95 px-3 py-1.5 text-xs text-[#6d5625] shadow-sm">
+            <span className="h-3.5 w-0.5 animate-pulse rounded-full bg-[#9b7a2f]" />
+            正在改写 Markdown
+          </div>
+        )}
         {showResumeAutoScroll && (
           <button
             type="button"
@@ -512,18 +574,28 @@ export function ArtifactFileDetail({
         {isSupportPreview &&
           viewMode === "preview" &&
           (language === "markdown" || language === "html") && (
-            <ArtifactFilePreview
+              <ArtifactFilePreview
-              content={displayContent}
+                content={displayContent}
-              language={language ?? "text"}
+                language={language ?? "text"}
-              animated={showPreviewSwitchPulse}
+                animated={showPreviewSwitchPulse}
-            />
+                activeCursor={isApplyingEdit}
-          )}
+              />
+            )}
         {isCodeFile && viewMode === "code" && (
           <div className="size-full">
             <CodeEditor
               className="size-full resize-none rounded-none border-none bg-transparent"
               value={displayContent ?? ""}
-              readonly
+              readonly={!canEditArtifact}
+              onChange={
+                canEditArtifact
+                  ? (value) => {
+                      setDraftContent(value);
+                      setHasLocalEdits(true);
+                    }
+                  : undefined
+              }
+              streamingReadonlyFallback={!canEditArtifact}
             />
           </div>
         )}
@@ -545,10 +617,12 @@ export function ArtifactFilePreview({
   content,
   language,
   animated = false,
+  activeCursor = false,
 }: {
   content: string;
   language: string;
   animated?: boolean;
+  activeCursor?: boolean;
 }) {
   const [htmlPreviewUrl, setHtmlPreviewUrl] = useState<string>();
 
@@ -583,6 +657,9 @@ export function ArtifactFilePreview({
         >
           {content ?? ""}
         </Streamdown>
+        {activeCursor && (
+          <span className="mt-2 inline-block h-5 w-0.5 animate-pulse rounded-full bg-[#9b7a2f]" />
+        )}
       </div>
     );
   }

frontend-web/src/components/workspace/code-editor.tsx

@@ -38,18 +38,22 @@ export function CodeEditor({
   className,
   placeholder,
   value,
+  onChange,
   readonly,
   disabled,
   autoFocus,
   settings,
+  streamingReadonlyFallback = true,
 }: {
   className?: string;
   placeholder?: string;
   value: string;
+  onChange?: (value: string) => void;
   readonly?: boolean;
   disabled?: boolean;
   autoFocus?: boolean;
   settings?: unknown;
+  streamingReadonlyFallback?: boolean;
 }) {
   const {
     thread: { isLoading },
@@ -77,7 +81,7 @@ export function CodeEditor({
         className,
       )}
     >
-      {isLoading ? (
+      {isLoading && streamingReadonlyFallback ? (
         <Textarea
           className={cn(
             "h-full overflow-auto font-mono [&_.cm-editor]:h-full [&_.cm-focused]:outline-none!",
@@ -107,6 +111,7 @@ export function CodeEditor({
           }}
           autoFocus={autoFocus}
           value={value}
+          onChange={onChange}
         />
       )}
     </div>

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

@@ -3,6 +3,7 @@
 import type { ChatStatus } from "ai";
 import {
   CheckIcon,
+  FileTextIcon,
   GraduationCapIcon,
   LightbulbIcon,
   PaperclipIcon,
@@ -124,6 +125,7 @@ export function InputBox({
   > & {
     mode: "flash" | "thinking" | "pro" | "ultra" | undefined;
     reasoning_effort?: "minimal" | "low" | "medium" | "high";
+    writing_mode?: boolean;
   };
   extraHeader?: React.ReactNode;
   isNewThread?: boolean;
@@ -136,6 +138,7 @@ export function InputBox({
     > & {
       mode: "flash" | "thinking" | "pro" | "ultra" | undefined;
       reasoning_effort?: "minimal" | "low" | "medium" | "high";
+      writing_mode?: boolean;
     },
   ) => void;
   onFollowupsVisibilityChange?: (visible: boolean) => void;
@@ -246,6 +249,13 @@ export function InputBox({
     [onContextChange, context],
   );
 
+  const handleWritingModeToggle = useCallback(() => {
+    onContextChange?.({
+      ...context,
+      writing_mode: !context.writing_mode,
+    });
+  }, [context, onContextChange]);
+
   const handleSubmit = useCallback(
     async (message: PromptInputMessage) => {
       if (status === "streaming") {
@@ -506,6 +516,26 @@ export function InputBox({
             </PromptInputActionMenuContent>
           </PromptInputActionMenu> */}
             <AddAttachmentsButton className="rounded-full border border-[#eee3d5] bg-[#fffaf5] px-2.5! shadow-none hover:bg-white" />
+            <Tooltip
+              content={
+                context.writing_mode
+                  ? "写作模式已开启：最终输出会强制保存为 Markdown 文件"
+                  : "开启写作模式：最终输出保存为 Markdown 文件并进入画布"
+              }
+            >
+              <PromptInputButton
+                className={cn(
+                  "gap-1.5! rounded-full border px-3! shadow-none",
+                  context.writing_mode
+                    ? "border-[#d8b878] bg-[#fff3cf] text-[#6d5625] hover:bg-[#ffedbd]"
+                    : "border-[#eee3d5] bg-[#fffaf5] text-[#7e6a57] hover:bg-white",
+                )}
+                onClick={handleWritingModeToggle}
+              >
+                <FileTextIcon className="size-3" />
+                <span className="text-xs font-normal">写作</span>
+              </PromptInputButton>
+            </Tooltip>
             <PromptInputActionMenu>
               <ModeHoverGuide
                 mode={

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

@@ -336,15 +336,18 @@ function ToolCall({
       description = t.toolCalls.writeFile;
     }
     const path: string | undefined = (args as { path: string })?.path;
+    const artifactPath =
+      name === "write_file" && path
+        ? new URL(
+            `write-file:${path}?message_id=${messageId}&tool_call_id=${id}`,
+          ).toString()
+        : path;
     if (isLoading && isLast && autoOpen && autoSelect && path && !result) {
       setTimeout(() => {
-        const url = new URL(
+        if (!artifactPath || selectedArtifact === artifactPath) {
-          `write-file:${path}?message_id=${messageId}&tool_call_id=${id}`,
-        ).toString();
-        if (selectedArtifact === url) {
           return;
         }
-        select(url, true);
+        select(artifactPath, true);
         setOpen(true);
       }, 100);
     }
@@ -356,11 +359,10 @@ function ToolCall({
         label={description}
         icon={NotebookPenIcon}
         onClick={() => {
-          select(
+          if (!artifactPath) {
-            new URL(
+            return;
-              `write-file:${path}?message_id=${messageId}&tool_call_id=${id}`,
+          }
-            ).toString(),
+          select(artifactPath);
-          );
           setOpen(true);
         }}
       >

frontend-web/src/core/artifacts/api.ts

@@ -0,0 +1,40 @@
+import { apiFetch } from "@/core/api";
+
+import { urlOfArtifact } from "./utils";
+
+async function errorMessageFromResponse(res: Response): Promise<string> {
+  try {
+    const data: unknown = await res.json();
+    if (data && typeof data === "object" && "detail" in data) {
+      const detail = (data as { detail: unknown }).detail;
+      if (typeof detail === "string") return detail;
+    }
+  } catch {
+    // ignore non-json errors
+  }
+  return res.statusText || "Request failed";
+}
+
+export async function updateArtifactContent({
+  filepath,
+  threadId,
+  content,
+  isMock,
+}: {
+  filepath: string;
+  threadId: string;
+  content: string;
+  isMock?: boolean;
+}) {
+  const res = await apiFetch(urlOfArtifact({ filepath, threadId, isMock }), {
+    method: "PATCH",
+    headers: {
+      "Content-Type": "application/json",
+    },
+    body: JSON.stringify({ content }),
+  });
+  if (!res.ok) {
+    throw new Error(await errorMessageFromResponse(res));
+  }
+  return res.text();
+}

frontend-web/src/core/artifacts/hooks.ts

@@ -1,9 +1,65 @@
-import { useQuery } from "@tanstack/react-query";
+import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
 import { useMemo } from "react";
 
 import { useThread } from "@/components/workspace/messages/context";
 
 import { loadArtifactContent, loadArtifactContentFromToolCall } from "./loader";
+import { updateArtifactContent } from "./api";
+
+function hasToolResult(thread: ReturnType<typeof useThread>["thread"], toolCallId?: string) {
+  if (!toolCallId) {
+    return false;
+  }
+  return thread.messages.some(
+    (message) => message.type === "tool" && message.tool_call_id === toolCallId,
+  );
+}
+
+function applyPendingTextEdit({
+  content,
+  filepath,
+  thread,
+}: {
+  content: string | undefined;
+  filepath: string;
+  thread: ReturnType<typeof useThread>["thread"];
+}) {
+  if (!content || !thread.isLoading) {
+    return null;
+  }
+
+  for (const message of [...thread.messages].reverse()) {
+    if (message.type !== "ai" || !message.tool_calls) {
+      continue;
+    }
+    for (const toolCall of [...message.tool_calls].reverse()) {
+      if (toolCall.name !== "str_replace" || hasToolResult(thread, toolCall.id)) {
+        continue;
+      }
+      const args = toolCall.args as {
+        path?: unknown;
+        old_str?: unknown;
+        new_str?: unknown;
+        replace_all?: unknown;
+      };
+      if (args.path !== filepath) {
+        continue;
+      }
+      if (typeof args.old_str !== "string" || typeof args.new_str !== "string") {
+        continue;
+      }
+      if (!content.includes(args.old_str)) {
+        return { content, kind: "editing" as const };
+      }
+      const nextContent =
+        args.replace_all === true
+          ? content.split(args.old_str).join(args.new_str)
+          : content.replace(args.old_str, args.new_str);
+      return { content: nextContent, kind: "editing" as const };
+    }
+  }
+  return null;
+}
 
 export function useArtifactContent({
   filepath,
@@ -31,13 +87,42 @@ export function useArtifactContent({
       return loadArtifactContent({ filepath, threadId, isMock });
     },
     enabled,
+    refetchInterval: thread.isLoading ? 1000 : false,
     // Cache artifact content for 5 minutes to avoid repeated fetches (especially for .skill ZIP extraction)
     staleTime: 5 * 60 * 1000,
   });
+  const pendingEdit = useMemo(() => {
+    if (isWriteFile) {
+      return null;
+    }
+    return applyPendingTextEdit({
+      content: data?.content,
+      filepath,
+      thread,
+    });
+  }, [data?.content, filepath, isWriteFile, thread]);
+
   return {
-    content: isWriteFile ? content : data?.content,
+    content: isWriteFile ? content : (pendingEdit?.content ?? data?.content),
     url: isWriteFile ? undefined : data?.url,
     isLoading,
+    isApplyingEdit: pendingEdit?.kind === "editing",
     error,
   };
 }
+
+export function useUpdateArtifactContent() {
+  const queryClient = useQueryClient();
+  return useMutation({
+    mutationFn: updateArtifactContent,
+    onSuccess: (content, variables) => {
+      queryClient.setQueryData(
+        ["artifact", variables.filepath, variables.threadId, variables.isMock],
+        {
+          content,
+          url: undefined,
+        },
+      );
+    },
+  });
+}

frontend-web/src/core/artifacts/index.ts

@@ -1,2 +1,3 @@
+export * from "./api";
 export * from "./download";
 export * from "./loader";

frontend-web/src/core/settings/local.ts

@@ -8,6 +8,7 @@ export const DEFAULT_LOCAL_SETTINGS: LocalSettings = {
     model_name: undefined,
     mode: undefined,
     reasoning_effort: undefined,
+    writing_mode: false,
   },
 };
 

frontend-web/src/core/threads/types.ts

@@ -16,6 +16,8 @@ export interface AgentThreadContext extends Record<string, unknown> {
   is_plan_mode: boolean;
   subagent_enabled: boolean;
   reasoning_effort?: "minimal" | "low" | "medium" | "high";
+  writing_mode?: boolean;
+  writing_artifact_path?: string;
   agent_id?: string;
   /** @deprecated kept for reading legacy thread metadata; prefer agent_id */
   agent_name?: string;

frontend-web/src/pages/ChatPage.tsx

@@ -1,9 +1,9 @@
 "use client";
 
-import { useCallback, useEffect, useState } from "react";
+import { useCallback, useEffect, useMemo, useState } from "react";
 
 import { type PromptInputMessage } from "@/components/ai-elements/prompt-input";
-import { ArtifactTrigger } from "@/components/workspace/artifacts";
+import { ArtifactTrigger, useArtifacts } from "@/components/workspace/artifacts";
 import {
   ChatBox,
   useSpecificChatMode,
@@ -39,6 +39,7 @@ export default function ChatPage() {
   const [settings, setSettings] = useThreadSettings(threadId);
   const [mounted, setMounted] = useState(false);
   const { tokenUsageEnabled } = useModels();
+  const { selectedArtifact } = useArtifacts();
   useSpecificChatMode();
 
   useEffect(() => {
@@ -85,15 +86,32 @@ export default function ChatPage() {
     },
   });
 
+  const writingArtifactPath = useMemo(() => {
+    const isMarkdown = (path: string | null | undefined) =>
+      !!path && /\.(md|markdown)(?:$|[?#])/i.test(path);
+    if (isMarkdown(selectedArtifact)) {
+      return selectedArtifact ?? undefined;
+    }
+    return [...(thread.values.artifacts ?? [])]
+      .reverse()
+      .find((path) => isMarkdown(path));
+  }, [selectedArtifact, thread.values.artifacts]);
+
   const handleSubmit = useCallback(
     (message: PromptInputMessage) => {
       setHasStartedConversation(true);
       window.dispatchEvent(
         new CustomEvent("workspace:sandbox-resume-autoscroll"),
       );
-      void sendMessage(threadId, message);
+      void sendMessage(
+        threadId,
+        message,
+        settings.context.writing_mode && writingArtifactPath
+          ? { writing_artifact_path: writingArtifactPath }
+          : undefined,
+      );
     },
-    [sendMessage, threadId],
+    [sendMessage, settings.context.writing_mode, threadId, writingArtifactPath],
   );
   const handleClarificationSubmit = useCallback(
     async (answer: string) => {

offline-backend-20260512/backend/app/gateway/routers/artifacts.py

@@ -6,6 +6,7 @@ from urllib.parse import quote
 
 from fastapi import APIRouter, HTTPException, Request
 from fastapi.responses import FileResponse, PlainTextResponse, Response
+from pydantic import BaseModel
 
 from app.gateway.authz import require_permission
 from app.gateway.path_utils import resolve_thread_virtual_path
@@ -20,6 +21,22 @@ ACTIVE_CONTENT_MIME_TYPES = {
     "image/svg+xml",
 }
 
+EDITABLE_TEXT_SUFFIXES = {
+    ".md",
+    ".markdown",
+    ".txt",
+    ".json",
+    ".yaml",
+    ".yml",
+    ".csv",
+    ".xml",
+    ".log",
+}
+
+
+class ArtifactUpdateRequest(BaseModel):
+    content: str
+
 
 def _build_content_disposition(disposition_type: str, filename: str) -> str:
     """Build an RFC 5987 encoded Content-Disposition header value."""
@@ -181,3 +198,44 @@ async def get_artifact(thread_id: str, path: str, request: Request, download: bo
         return PlainTextResponse(content=actual_path.read_text(encoding="utf-8"), media_type=mime_type)
 
     return Response(content=actual_path.read_bytes(), media_type=mime_type, headers={"Content-Disposition": _build_content_disposition("inline", actual_path.name)})
+
+
+@router.patch(
+    "/threads/{thread_id}/artifacts/{path:path}",
+    summary="Update Artifact File",
+    description="Update a text artifact file in the current thread workspace.",
+)
+@require_permission("threads", "write", owner_check=True)
+async def update_artifact(
+    thread_id: str,
+    path: str,
+    request: Request,
+    body: ArtifactUpdateRequest,
+) -> Response:
+    """Update a text artifact.
+
+    This endpoint is intentionally limited to normal text artifacts. Files inside
+    .skill archives and active web content remain read-only from the artifact UI.
+    """
+    if ".skill/" in path:
+        raise HTTPException(status_code=400, detail="Skill archive contents are read-only.")
+
+    actual_path = resolve_thread_virtual_path(thread_id, path)
+    logger.info(f"Updating artifact path: thread_id={thread_id}, requested_path={path}, actual_path={actual_path}")
+
+    if not actual_path.exists():
+        raise HTTPException(status_code=404, detail=f"Artifact not found: {path}")
+
+    if not actual_path.is_file():
+        raise HTTPException(status_code=400, detail=f"Path is not a file: {path}")
+
+    mime_type, _ = mimetypes.guess_type(actual_path)
+    suffix = actual_path.suffix.lower()
+    if mime_type in ACTIVE_CONTENT_MIME_TYPES:
+        raise HTTPException(status_code=400, detail="Active web artifacts are read-only.")
+
+    if suffix not in EDITABLE_TEXT_SUFFIXES and not (mime_type and mime_type.startswith("text/")):
+        raise HTTPException(status_code=400, detail="Only text artifacts can be edited.")
+
+    actual_path.write_text(body.content, encoding="utf-8")
+    return PlainTextResponse(content=body.content, media_type=mime_type or "text/plain")

offline-backend-20260512/backend/app/gateway/services.py

@@ -111,6 +111,8 @@ _CONTEXT_CONFIGURABLE_KEYS: frozenset[str] = frozenset(
         "mode",
         "thinking_enabled",
         "reasoning_effort",
+        "writing_mode",
+        "writing_artifact_path",
         "is_plan_mode",
         "subagent_enabled",
         "max_concurrent_subagents",

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

@@ -330,6 +330,10 @@ def _make_lead_agent(config: RunnableConfig, *, app_config: AppConfig):
     subagent_enabled = cfg.get("subagent_enabled", False)
     max_concurrent_subagents = cfg.get("max_concurrent_subagents", 3)
     is_bootstrap = cfg.get("is_bootstrap", False)
+    writing_mode = bool(cfg.get("writing_mode", False))
+    writing_artifact_path = cfg.get("writing_artifact_path") if writing_mode else None
+    if not isinstance(writing_artifact_path, str) or not writing_artifact_path.strip():
+        writing_artifact_path = None
     agent_id = validate_agent_id(cfg.get("agent_id") or cfg.get("agent_name"))
 
     agent_config = load_agent_config(agent_id) if not is_bootstrap else None
@@ -349,7 +353,7 @@ def _make_lead_agent(config: RunnableConfig, *, app_config: AppConfig):
         thinking_enabled = False
 
     logger.info(
-        "Create Agent(%s) -> thinking_enabled: %s, reasoning_effort: %s, model_name: %s, is_plan_mode: %s, subagent_enabled: %s, max_concurrent_subagents: %s",
+        "Create Agent(%s) -> thinking_enabled: %s, reasoning_effort: %s, model_name: %s, is_plan_mode: %s, subagent_enabled: %s, max_concurrent_subagents: %s, writing_mode: %s",
         agent_id or "default",
         thinking_enabled,
         reasoning_effort,
@@ -357,6 +361,7 @@ def _make_lead_agent(config: RunnableConfig, *, app_config: AppConfig):
         is_plan_mode,
         subagent_enabled,
         max_concurrent_subagents,
+        writing_mode,
     )
 
     # Inject run metadata for LangSmith trace tagging
@@ -381,6 +386,8 @@ def _make_lead_agent(config: RunnableConfig, *, app_config: AppConfig):
             "reasoning_effort": reasoning_effort,
             "is_plan_mode": is_plan_mode,
             "subagent_enabled": subagent_enabled,
+            "writing_mode": writing_mode,
+            "writing_artifact_path": writing_artifact_path,
             "tool_groups": agent_config.tool_groups if agent_config else None,
             "available_skills": runtime_available_skills,
         }
@@ -401,6 +408,8 @@ def _make_lead_agent(config: RunnableConfig, *, app_config: AppConfig):
             system_prompt=apply_prompt_template(
                 subagent_enabled=subagent_enabled,
                 max_concurrent_subagents=max_concurrent_subagents,
+                writing_mode=writing_mode,
+                writing_artifact_path=writing_artifact_path,
                 available_skills=set(["bootstrap"]),
                 app_config=resolved_app_config,
             ),
@@ -423,6 +432,8 @@ def _make_lead_agent(config: RunnableConfig, *, app_config: AppConfig):
             max_concurrent_subagents=max_concurrent_subagents,
             agent_id=agent_id,
             agent_name=agent_display_name,
+            writing_mode=writing_mode,
+            writing_artifact_path=writing_artifact_path,
             available_skills=(set(agent_config.skills or []) if agent_config else None),
             app_config=resolved_app_config,
         ),

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

@@ -474,6 +474,8 @@ You: "Deploying to staging..." [proceed]
 
 {deferred_tools_section}
 
+{writing_mode_section}
+
 {subagent_section}
 
 <working_directory existed="true">
@@ -793,6 +795,8 @@ def apply_prompt_template(
     *,
     agent_id: str | None = None,
     agent_name: str | None = None,
+    writing_mode: bool = False,
+    writing_artifact_path: str | None = None,
     available_skills: set[str] | None = None,
     app_config: AppConfig | None = None,
 ) -> str:
@@ -828,6 +832,32 @@ def apply_prompt_template(
 
     # Get deferred tools section (tool_search)
     deferred_tools_section = get_deferred_tools_prompt_section(app_config=app_config)
+    current_writing_artifact = (
+        f"\n**Current Markdown Artifact**\n- Continue editing this existing Markdown file unless the user explicitly asks for a new document: `{writing_artifact_path}`\n"
+        if writing_artifact_path
+        else ""
+    )
+    writing_mode_section = (
+        f"""
+<writing_mode>
+Writing mode is enabled for this run.
+
+**Mandatory Output Contract**
+- Treat the user's request as a writing/report-generation task.
+- Your final deliverable MUST be a Markdown file, not only an inline chat answer.
+- If a current Markdown artifact is provided below, you MUST revise that existing file rather than creating a new file, unless the user explicitly asks for a separate/new document.
+- When revising an existing Markdown artifact, read the file first if needed, then overwrite the same path with the complete updated Markdown content.
+- Write the deliverable to `/mnt/user-data/outputs/` with a clear `.md` filename, for example `/mnt/user-data/outputs/report.md`.
+- Use `write_file` or an equivalent file-writing tool to save the complete Markdown content.
+- After writing the file, call `present_files` with the Markdown file path so the user can open it as an artifact/canvas.
+- The final chat response should be brief and point to the generated Markdown artifact. Do not duplicate the full report inline unless the user explicitly asks.
+- If you revise an existing Markdown artifact, update the Markdown file and present it again.
+{current_writing_artifact}
+</writing_mode>
+"""
+        if writing_mode
+        else ""
+    )
 
     # Build ACP agent section only if ACP agents are configured
     acp_section = _build_acp_section(app_config=app_config)
@@ -843,6 +873,7 @@ def apply_prompt_template(
         soul=get_agent_soul(storage_agent_id),
         skills_section=skills_section,
         deferred_tools_section=deferred_tools_section,
+        writing_mode_section=writing_mode_section,
         memory_context=memory_context,
         network_policy_section=network_policy_section,
         subagent_section=subagent_section,