diff --git a/apps/web/components/workbench/Editor.tsx b/apps/web/components/workbench/Editor.tsx
index 3ff184c..0f9a20a 100644
--- a/apps/web/components/workbench/Editor.tsx
+++ b/apps/web/components/workbench/Editor.tsx
@@ -4,17 +4,37 @@ import { useEffect, useRef } from "react";
 
 import { cn, focusRing, proseBody } from "@/lib/ui/variants";
 
+export interface EditorSelection {
+  start: number;
+  end: number;
+  text: string;
+}
+
 interface EditorProps {
   value: string;
   onChange: (value: string) => void;
   streaming: boolean;
+  // 选区变化上报（供「润色选段」等选区级 AI 动作取材）。空选区也会上报（start===end）。
+  onSelectionChange?: (selection: EditorSelection) => void;
 }
 
 // 中栏正文编辑器：宋体、720px 居中、行高 1.9（UX §2.3 / §6.3）。
 // 流式中显示朱砂光标提示（prefers-reduced-motion 下不闪烁，见 globals.css）。
-export function Editor({ value, onChange, streaming }: EditorProps) {
+export function Editor({
+  value,
+  onChange,
+  streaming,
+  onSelectionChange,
+}: EditorProps) {
   const ref = useRef<HTMLTextAreaElement>(null);
 
+  const reportSelection = (el: HTMLTextAreaElement): void => {
+    if (!onSelectionChange) return;
+    const start = el.selectionStart;
+    const end = el.selectionEnd;
+    onSelectionChange({ start, end, text: value.slice(start, end) });
+  };
+
   // 自适应高度：textarea 高度=内容高度（overflow-hidden 不内部滚动），由外层写作区
   // 单一滚动条统管。修复正文出现嵌套滚动条 + 定高 60vh 不铺满展示区的怪象。
   // min-h-[60vh] 仍作空稿时的最小可写高度（内容更长时按内容增高、外层滚动）。
@@ -35,6 +55,7 @@ export function Editor({ value, onChange, streaming }: EditorProps) {
         id="chapter-editor"
         value={value}
         onChange={(e) => onChange(e.target.value)}
+        onSelect={(e) => reportSelection(e.currentTarget)}
         readOnly={streaming}
         aria-busy={streaming}
         placeholder="夜色如墨……点击「写本章」让 AI 起草，或直接在此书写。"
diff --git a/apps/web/components/workbench/RefinePanel.tsx b/apps/web/components/workbench/RefinePanel.tsx
new file mode 100644
index 0000000..5a31a1c
--- /dev/null
+++ b/apps/web/components/workbench/RefinePanel.tsx
@@ -0,0 +1,133 @@
+"use client";
+
+import { useEffect, useRef, useState } from "react";
+import { Check, MessageSquarePlus, RotateCcw, X } from "lucide-react";
+
+import { ThinkingIndicator } from "@/components/ThinkingIndicator";
+import { Button } from "@/components/ui/Button";
+import { SectionHeader } from "@/components/ui/SectionHeader";
+import { StatusNote } from "@/components/ui/StatusNote";
+import { TextArea } from "@/components/ui/TextArea";
+import { useRefine } from "@/lib/workbench/useRefine";
+
+interface RefinePanelProps {
+  projectId: string;
+  chapterNo: number;
+  // 选中原文；打开即对其回炉一次。
+  original: string;
+  // 接受回填：把选段替换为该产出（调用方按内容重锚落回草稿）。
+  onAccept: (refined: string) => void;
+  onClose: () => void;
+}
+
+// 润色 / 再沟通结果卡（内联，非模态）：打开即润色选段；作者可「再沟通」追加意见迭代出新版，
+// 择版接受回填正文，或放弃。原文只读、生成不写库（不变量 #3），accept 才动草稿。
+export function RefinePanel({
+  projectId,
+  chapterNo,
+  original,
+  onAccept,
+  onClose,
+}: RefinePanelProps) {
+  const { status, versions, latest, refine, recommunicate } = useRefine();
+  const [instruction, setInstruction] = useState("");
+  const ranRef = useRef(false);
+
+  // 打开即对选段回炉一次（仅一次，避免重复请求）。
+  useEffect(() => {
+    if (ranRef.current) return;
+    ranRef.current = true;
+    void refine(projectId, chapterNo, original);
+  }, [projectId, chapterNo, original, refine]);
+
+  const busy = status === "refining";
+
+  const onRecommunicate = (): void => {
+    const trimmed = instruction.trim();
+    if (!trimmed || busy) return;
+    setInstruction("");
+    void recommunicate(projectId, chapterNo, trimmed);
+  };
+
+  return (
+    <div className="border-b border-line bg-panel px-4 py-3 sm:px-6">
+      <div className="flex items-center justify-between gap-3">
+        <SectionHeader
+          title="润色 / 再沟通"
+          description="对选中段回炉；不满意可追加意见让 AI 再改一版，满意后接受回填。"
+        />
+        <Button onClick={onClose} variant="ghost" size="icon" aria-label="关闭润色">
+          <X className="h-4 w-4" aria-hidden="true" />
+        </Button>
+      </div>
+
+      <div className="mt-3 grid gap-3 sm:grid-cols-2">
+        <figure className="rounded border border-line bg-bg p-3">
+          <figcaption className="mb-1 text-2xs text-ink-soft">原文</figcaption>
+          <p className="whitespace-pre-wrap text-sm text-ink-soft">{original}</p>
+        </figure>
+        <figure className="rounded border border-cinnabar/40 bg-bg p-3">
+          <figcaption className="mb-1 flex items-center gap-2 text-2xs text-ink-soft">
+            改写
+            {versions.length > 0 ? (
+              <span className="rounded bg-panel px-1.5 py-0.5 tabular-nums">
+                第 {versions.length} 版
+              </span>
+            ) : null}
+          </figcaption>
+          {busy && !latest ? (
+            <ThinkingIndicator label="润色中" className="text-xs text-cinnabar" />
+          ) : latest ? (
+            <p className="whitespace-pre-wrap text-sm text-ink">{latest.refined}</p>
+          ) : status === "error" ? (
+            <StatusNote variant="danger" className="text-xs" title="回炉失败">
+              <button
+                type="button"
+                onClick={() => void refine(projectId, chapterNo, original)}
+                className="mt-1 inline-flex items-center gap-1 text-cinnabar hover:underline"
+              >
+                <RotateCcw className="h-3.5 w-3.5" aria-hidden="true" />
+                重试
+              </button>
+            </StatusNote>
+          ) : null}
+        </figure>
+      </div>
+
+      <div className="mt-3 space-y-2">
+        <label className="block">
+          <span className="sr-only">再沟通意见</span>
+          <TextArea
+            value={instruction}
+            onChange={(e) => setInstruction(e.target.value)}
+            rows={2}
+            placeholder="再沟通：想怎么改？（如「再收紧节奏」「保留这句比喻」）"
+          />
+        </label>
+        <div className="flex flex-wrap items-center gap-2">
+          <Button
+            onClick={onRecommunicate}
+            disabled={busy || instruction.trim().length === 0}
+            variant="secondary"
+            size="sm"
+          >
+            <MessageSquarePlus className="h-4 w-4" aria-hidden="true" />
+            再改一版
+          </Button>
+          <Button
+            onClick={() => latest && onAccept(latest.refined)}
+            disabled={busy || !latest}
+            variant="primary"
+            size="sm"
+          >
+            <Check className="h-4 w-4" aria-hidden="true" />
+            接受回填
+          </Button>
+          {busy ? (
+            <ThinkingIndicator label="生成中" className="text-xs text-cinnabar" />
+          ) : null}
+        </div>
+      </div>
+    </div>
+  );
+}
diff --git a/apps/web/components/workbench/Workbench.tsx b/apps/web/components/workbench/Workbench.tsx
index abe7203..391dc70 100644
--- a/apps/web/components/workbench/Workbench.tsx
+++ b/apps/web/components/workbench/Workbench.tsx
@@ -12,11 +12,13 @@ import {
   PanelRight,
   PenLine,
   Square,
+  Wand2,
 } from "lucide-react";
 
 import { AppShell } from "@/components/AppShell";
 import { Drawer } from "@/components/Drawer";
 import { ThinkingIndicator } from "@/components/ThinkingIndicator";
+import { useToast } from "@/components/Toast";
 import { Button } from "@/components/ui/Button";
 import { SectionHeader } from "@/components/ui/SectionHeader";
 import { StatusNote } from "@/components/ui/StatusNote";
@@ -30,10 +32,12 @@ import {
   type ChapterEntry,
 } from "@/lib/workbench/chapter";
 import { composeDirective, STYLE_PRESETS } from "@/lib/workbench/directive";
+import { applyRefinement } from "@/lib/workbench/refineApply";
 import { buttonClass } from "@/lib/ui/variants";
 import { ChapterList, ChapterListContent } from "./ChapterList";
 import { ChapterAssistant, AssistantContent } from "./ChapterAssistant";
-import { Editor } from "./Editor";
+import { Editor, type EditorSelection } from "./Editor";
+import { RefinePanel } from "./RefinePanel";
 
 interface WorkbenchProps {
   project: ProjectResponse;
@@ -64,9 +68,14 @@ export function Workbench({
   // 本章指令（T4-b）：自由文本 + 风格预设 → 写本章时组装传入 draft 生成。
   const [directive, setDirective] = useState("");
   const [presetIds, setPresetIds] = useState<string[]>([]);
+  // 选区级 AI 动作（润色/再沟通）：编辑器上报的最新选区 + 结果卡开合。
+  const [selection, setSelection] = useState<EditorSelection | null>(null);
+  const [refineOpen, setRefineOpen] = useState(false);
+  const toast = useToast();
   const autosave = useAutosave(project.id, chapterNo, initialText);
   const stream = useDraftStream();
   const lastStreamText = useRef("");
+  const canRefine = selection !== null && selection.text.trim().length > 0;
   const chapterTriggerRef = useRef<HTMLButtonElement>(null);
   const assistantTriggerRef = useRef<HTMLButtonElement>(null);
 
@@ -104,6 +113,24 @@ export function Workbench({
     autosave.onChange(value);
   };
 
+  // 接受润色/再沟通产出：按内容重锚把选段替换为产出并落草稿；原文已变则提示重选（不盲替换）。
+  const onAcceptRefine = (refined: string): void => {
+    if (selection) {
+      const next = applyRefinement(text, selection.text, refined, {
+        start: selection.start,
+        end: selection.end,
+      });
+      if (next === null) {
+        toast("正文已改动，找不到原选段，请重新选择后再润色。", "error");
+      } else {
+        setText(next);
+        autosave.onChange(next);
+      }
+    }
+    setRefineOpen(false);
+    setSelection(null);
+  };
+
   // 字数统计非空白字符（与中文读者直觉一致：标点/空格不计入正文体量）。
   const wordCount = text.replace(/\s+/g, "").length;
   const closePanel = (): void => setMobilePanel(null);
@@ -153,11 +180,21 @@ export function Workbench({
             presetIds={presetIds}
             onTogglePreset={togglePreset}
           />
+          {refineOpen && canRefine && selection ? (
+            <RefinePanel
+              projectId={project.id}
+              chapterNo={chapterNo}
+              original={selection.text}
+              onAccept={onAcceptRefine}
+              onClose={() => setRefineOpen(false)}
+            />
+          ) : null}
           <div className="flex-1 overflow-auto px-6 py-8">
             <Editor
               value={text}
               onChange={onEditorChange}
               streaming={stream.isStreaming}
+              onSelectionChange={setSelection}
             />
           </div>
           <Toolbar
@@ -171,6 +208,8 @@ export function Workbench({
             liveMessage={liveMessage}
             onWrite={onWrite}
             onStop={stream.stop}
+            canRefine={canRefine}
+            onRefineSelection={() => setRefineOpen(true)}
           />
         </section>
 
@@ -358,6 +397,9 @@ interface ToolbarProps {
   liveMessage: string;
   onWrite: () => void;
   onStop: () => void;
+  // 选区级润色：有非空选区时可用；点击打开润色/再沟通结果卡。
+  canRefine: boolean;
+  onRefineSelection: () => void;
 }
 
 function Toolbar({
@@ -371,6 +413,8 @@ function Toolbar({
   liveMessage,
   onWrite,
   onStop,
+  canRefine,
+  onRefineSelection,
 }: ToolbarProps) {
   return (
     <div className="sticky bottom-0 z-10 border-t border-line bg-panel/95 px-4 py-2 backdrop-blur sm:px-6 sm:py-3">
@@ -388,6 +432,18 @@ function Toolbar({
             写本章
           </Button>
         )}
+        {!streaming ? (
+          <Button
+            onClick={onRefineSelection}
+            disabled={!canRefine}
+            variant="secondary"
+            size="sm"
+            title={canRefine ? undefined : "先在正文里选中一段再润色"}
+          >
+            <Wand2 className="h-4 w-4" aria-hidden="true" />
+            润色选段
+          </Button>
+        ) : null}
         {streaming ? (
           // ThinkingIndicator 自带 role=status，开始时播报一次「生成中」；
           // 易变字数 aria-hidden，仅供视觉，不逐 token 打扰屏读。
diff --git a/apps/web/lib/workbench/refineApply.test.ts b/apps/web/lib/workbench/refineApply.test.ts
new file mode 100644
index 0000000..84cc355
--- /dev/null
+++ b/apps/web/lib/workbench/refineApply.test.ts
@@ -0,0 +1,37 @@
+import { describe, expect, it } from "vitest";
+
+import { applyRefinement } from "./refineApply";
+
+describe("applyRefinement", () => {
+  const full = "第一段。原文段落。第三段。";
+  const original = "原文段落。";
+  const refined = "润色后的段落。";
+  // "第一段。" = 4 字，原文段落在 [4, 4+len)
+  const range = { start: 4, end: 4 + original.length };
+
+  it("选区未漂移：按 range 原地替换", () => {
+    expect(applyRefinement(full, original, refined, range)).toBe(
+      "第一段。润色后的段落。第三段。",
+    );
+  });
+
+  it("选区漂移但原文唯一：按内容重锚替换", () => {
+    // range 指向错位（如流式追加导致偏移），但原文仍能唯一定位。
+    const drifted = { start: 0, end: 3 };
+    expect(applyRefinement(full, original, refined, drifted)).toBe(
+      "第一段。润色后的段落。第三段。",
+    );
+  });
+
+  it("原文已不存在（正文被大改）：返回 null 让调用方提示重选", () => {
+    expect(applyRefinement("完全不同的正文", original, refined, range)).toBeNull();
+  });
+
+  it("只替换首个匹配（重锚回退时保守取第一处）", () => {
+    const twice = "原文段落。中间。原文段落。";
+    const drifted = { start: 99, end: 100 };
+    expect(applyRefinement(twice, original, refined, drifted)).toBe(
+      "润色后的段落。中间。原文段落。",
+    );
+  });
+});
diff --git a/apps/web/lib/workbench/refineApply.ts b/apps/web/lib/workbench/refineApply.ts
new file mode 100644
index 0000000..17cb752
--- /dev/null
+++ b/apps/web/lib/workbench/refineApply.ts
@@ -0,0 +1,24 @@
+// 润色/再沟通 accept 回填：把选中原文替换为产出。选区偏移可能因异步/流式漂移，
+// 故先按 range 校验，未命中则按原文内容重锚（indexOf）——原文已不存在则返回 null，
+// 由调用方提示作者重新选择，绝不盲替换（plan §3.3 mustFix）。
+
+export interface SelectionRange {
+  start: number;
+  end: number;
+}
+
+export function applyRefinement(
+  fullText: string,
+  original: string,
+  refined: string,
+  range: SelectionRange,
+): string | null {
+  // 选区未漂移：range 处正好是原文 → 原地替换。
+  if (fullText.slice(range.start, range.end) === original) {
+    return fullText.slice(0, range.start) + refined + fullText.slice(range.end);
+  }
+  // 漂移：按内容重锚，保守取首个匹配。
+  const idx = fullText.indexOf(original);
+  if (idx === -1) return null;
+  return fullText.slice(0, idx) + refined + fullText.slice(idx + original.length);
+}
diff --git a/apps/web/lib/workbench/useRefine.test.ts b/apps/web/lib/workbench/useRefine.test.ts
new file mode 100644
index 0000000..574d5b5
--- /dev/null
+++ b/apps/web/lib/workbench/useRefine.test.ts
@@ -0,0 +1,131 @@
+// @vitest-environment jsdom
+import { act, renderHook } from "@testing-library/react";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+
+import { useRefine } from "./useRefine";
+
+// 后端客户端与 Toast 是 hook 的外部副作用边界，单测一律 mock。
+const post = vi.fn();
+const toast = vi.fn();
+vi.mock("@/lib/api/client", () => ({
+  api: { POST: (...a: unknown[]) => post(...a) },
+}));
+vi.mock("@/components/Toast", () => ({ useToast: () => toast }));
+
+const REFINE_PATH = "/projects/{project_id}/chapters/{chapter_no}/refine";
+
+describe("useRefine", () => {
+  beforeEach(() => {
+    post.mockReset();
+    toast.mockReset();
+  });
+  afterEach(() => vi.clearAllMocks());
+
+  it("初始为 idle，无版本、无原文", () => {
+    const { result } = renderHook(() => useRefine());
+    expect(result.current.status).toBe("idle");
+    expect(result.current.versions).toEqual([]);
+    expect(result.current.latest).toBeNull();
+    expect(result.current.original).toBeNull();
+  });
+
+  it("润色：调 /refine，压入一版，original=选中原文，status=ready", async () => {
+    post.mockResolvedValue({
+      data: { original: "原文段", refined: "润色后的段落" },
+      error: null,
+    });
+
+    const { result } = renderHook(() => useRefine());
+    await act(async () => {
+      await result.current.refine("p1", 3, "原文段");
+    });
+
+    expect(post).toHaveBeenCalledWith(REFINE_PATH, {
+      params: { path: { project_id: "p1", chapter_no: 3 } },
+      body: { segment: "原文段" },
+    });
+    expect(result.current.status).toBe("ready");
+    expect(result.current.original).toBe("原文段");
+    expect(result.current.latest).toEqual({
+      segment: "原文段",
+      instruction: "",
+      refined: "润色后的段落",
+    });
+    expect(result.current.versions).toHaveLength(1);
+  });
+
+  it("润色带指令：instruction 透传后端", async () => {
+    post.mockResolvedValue({ data: { original: "s", refined: "r" }, error: null });
+    const { result } = renderHook(() => useRefine());
+    await act(async () => {
+      await result.current.refine("p1", 1, "原文", "更口语一点");
+    });
+    expect(post).toHaveBeenCalledWith(REFINE_PATH, {
+      params: { path: { project_id: "p1", chapter_no: 1 } },
+      body: { segment: "原文", instruction: "更口语一点" },
+    });
+  });
+
+  it("再沟通：以上一版产出为输入 + 作者新意见，压入新版，original 不变", async () => {
+    post
+      .mockResolvedValueOnce({ data: { original: "原文", refined: "第一版" }, error: null })
+      .mockResolvedValueOnce({ data: { original: "第一版", refined: "第二版" }, error: null });
+
+    const { result } = renderHook(() => useRefine());
+    await act(async () => {
+      await result.current.refine("p1", 2, "原文");
+    });
+    await act(async () => {
+      await result.current.recommunicate("p1", 2, "再收紧节奏");
+    });
+
+    expect(post).toHaveBeenLastCalledWith(REFINE_PATH, {
+      params: { path: { project_id: "p1", chapter_no: 2 } },
+      body: { segment: "第一版", instruction: "再收紧节奏" },
+    });
+    expect(result.current.versions).toHaveLength(2);
+    expect(result.current.original).toBe("原文");
+    expect(result.current.latest?.refined).toBe("第二版");
+  });
+
+  it("无历史版本时再沟通为空操作（不打后端）", async () => {
+    const { result } = renderHook(() => useRefine());
+    await act(async () => {
+      await result.current.recommunicate("p1", 1, "改一下");
+    });
+    expect(post).not.toHaveBeenCalled();
+  });
+
+  it("后端返回 error：status=error、弹错误 toast、版本栈不变", async () => {
+    post.mockResolvedValue({ data: null, error: { detail: "配额不足" } });
+    const { result } = renderHook(() => useRefine());
+    await act(async () => {
+      await result.current.refine("p1", 1, "原文");
+    });
+    expect(result.current.status).toBe("error");
+    expect(result.current.versions).toEqual([]);
+    expect(toast).toHaveBeenCalledWith(expect.any(String), "error");
+  });
+
+  it("请求抛异常：status=error、弹网络异常 toast", async () => {
+    post.mockRejectedValue(new Error("network down"));
+    const { result } = renderHook(() => useRefine());
+    await act(async () => {
+      await result.current.refine("p1", 1, "原文");
+    });
+    expect(result.current.status).toBe("error");
+    expect(toast).toHaveBeenCalledWith("回炉请求异常，请检查网络。", "error");
+  });
+
+  it("reset 清回 idle 与空版本", async () => {
+    post.mockResolvedValue({ data: { original: "s", refined: "r" }, error: null });
+    const { result } = renderHook(() => useRefine());
+    await act(async () => {
+      await result.current.refine("p1", 1, "s");
+    });
+    act(() => result.current.reset());
+    expect(result.current.status).toBe("idle");
+    expect(result.current.versions).toEqual([]);
+    expect(result.current.latest).toBeNull();
+  });
+});
diff --git a/apps/web/lib/workbench/useRefine.ts b/apps/web/lib/workbench/useRefine.ts
new file mode 100644
index 0000000..2d795be
--- /dev/null
+++ b/apps/web/lib/workbench/useRefine.ts
@@ -0,0 +1,112 @@
+"use client";
+
+import { useCallback, useMemo, useState } from "react";
+
+import { api } from "@/lib/api/client";
+import { useToast } from "@/components/Toast";
+
+// 编辑器内「润色 / 再沟通」核心（复用同步 /refine，只读、不写库——不变量 #3）。
+// 润色：对选中段回炉一次。再沟通：以上一版产出为输入 + 作者新意见再回炉，形成版本栈，
+// 作者可回看每一版、择一 accept 回填正文（accept/回填由组件负责，此处只管生成与版本历史）。
+
+export interface RefineVersion {
+  // 本次回炉的输入段：首轮 = 选中原文；再沟通 = 上一版产出。
+  segment: string;
+  // 本次改写指令（再沟通时为作者的新意见）；无则空串。
+  instruction: string;
+  refined: string;
+}
+
+export type RefineStatus = "idle" | "refining" | "ready" | "error";
+
+export interface UseRefine {
+  status: RefineStatus;
+  versions: RefineVersion[];
+  // 版本栈顶（最新产出）。
+  latest: RefineVersion | null;
+  // 最初选中的原文（accept 回填的对比基线）。
+  original: string | null;
+  refine: (
+    projectId: string,
+    chapterNo: number,
+    segment: string,
+    instruction?: string,
+  ) => Promise<void>;
+  // 以上一版产出为输入 + 作者新意见再回炉一次。无历史版本时为空操作。
+  recommunicate: (
+    projectId: string,
+    chapterNo: number,
+    instruction: string,
+  ) => Promise<void>;
+  reset: () => void;
+}
+
+export function useRefine(): UseRefine {
+  const [status, setStatus] = useState<RefineStatus>("idle");
+  const [versions, setVersions] = useState<RefineVersion[]>([]);
+  const toast = useToast();
+
+  const runRefine = useCallback(
+    async (
+      projectId: string,
+      chapterNo: number,
+      segment: string,
+      instruction: string,
+    ): Promise<void> => {
+      setStatus("refining");
+      try {
+        const trimmed = instruction.trim();
+        const { data, error } = await api.POST(
+          "/projects/{project_id}/chapters/{chapter_no}/refine",
+          {
+            params: { path: { project_id: projectId, chapter_no: chapterNo } },
+            body: trimmed ? { segment, instruction: trimmed } : { segment },
+          },
+        );
+        if (error || !data) {
+          setStatus("error");
+          toast("回炉失败，请重试。", "error");
+          return;
+        }
+        setVersions((prev) => [
+          ...prev,
+          { segment, instruction: trimmed, refined: data.refined },
+        ]);
+        setStatus("ready");
+      } catch {
+        setStatus("error");
+        toast("回炉请求异常，请检查网络。", "error");
+      }
+    },
+    [toast],
+  );
+
+  const refine = useCallback<UseRefine["refine"]>(
+    (projectId, chapterNo, segment, instruction) =>
+      runRefine(projectId, chapterNo, segment, instruction ?? ""),
+    [runRefine],
+  );
+
+  const recommunicate = useCallback<UseRefine["recommunicate"]>(
+    (projectId, chapterNo, instruction) => {
+      const last = versions[versions.length - 1];
+      // 无历史版本 → 无从「再沟通」；空操作，不打后端。
+      if (!last) return Promise.resolve();
+      return runRefine(projectId, chapterNo, last.refined, instruction);
+    },
+    [runRefine, versions],
+  );
+
+  const reset = useCallback((): void => {
+    setStatus("idle");
+    setVersions([]);
+  }, []);
+
+  const latest = versions.at(-1) ?? null;
+  const original = versions[0]?.segment ?? null;
+
+  return useMemo(
+    () => ({ status, versions, latest, original, refine, recommunicate, reset }),
+    [status, versions, latest, original, refine, recommunicate, reset],
+  );
+}