feat(frontend): 五类交互接入 AI 对话留痕 + Workbench 抽屉入口（AC-3）

- RefinePanel/ChapterRewritePanel：结束后 append [author(意见/答复), ai(产出)]；
  clarify buffer-until-concluded——澄清 Q&A（原意见→反问→答复）缓冲，随最终产出批
  一起落库同 thread；纯放弃不记。refine ai 行 meta 存 version_no+原选段（每版重锚）。
- ContinuePanel：ai-only（续写无作者输入），每候选一条 ai 气泡 meta{candidate_index}。
- GeneratorRunner：成功后 append [author(字段摘要, meta{tool_key,input_fields}),
  ai(渲染预览, meta{tool_key,output_kind})]；空产物不记。lib/toolbox/aiSummary.ts 纯助手+单测。
- InlineToolbox→GeneratorRunner 透传 append+本章号；ToolboxPage 用 silent 直投项目级(chapter_no=null)。
- Workbench：挂 useAiConversation 单实例 + AiConversationDrawer + 底栏「AI 对话」入口（flag 灰度），
  三个 DRAFT-only 再接受回调（替换整章/插入正文/回填选段），成功关抽屉+toast、漂移不盲替换。

apps/web/components/toolbox/GeneratorRunner.tsx

@@ -1,6 +1,6 @@
 "use client";
 
-import { useCallback, useMemo, useState } from "react";
+import { useCallback, useMemo, useRef, useState } from "react";
 import { ArrowLeft, Database, Sparkles } from "lucide-react";
 
 import { useToast } from "@/components/Toast";
@@ -23,8 +23,10 @@ import {
   type PreviewItem,
 } from "@/lib/toolbox/toolbox";
 import { ingestTable, isSingleObjectIngest } from "@/lib/toolbox/ingest";
+import { fieldSummary, renderPreviewText } from "@/lib/toolbox/aiSummary";
 import { buildManuscriptExcerpt } from "@/lib/workbench/manuscriptExcerpt";
 import { useGenerator } from "@/lib/toolbox/useGenerator";
+import type { AiTurnInput } from "@/lib/workbench/useAiConversation";
 import { TemplateFiller } from "./TemplateFiller";
 
 interface GeneratorRunnerProps {
@@ -36,6 +38,10 @@ interface GeneratorRunnerProps {
   // 可选：作者【已写正文】。传入且当前工具有 brief 字段时，表单里出现「用当前正文」按钮，
   // 点击把正文摘录填进 brief，让内容感知型生成器（如书名）据正文反推。工具箱页不传 → 不显示。
   manuscriptText?: string;
+  // 可选留痕：生成成功后 append 一批 [author(字段摘要), ai(预览文本)]。
+  // 内联工具箱传 conversation.appendMessages + 当前章号；工具箱页传 silent 直投 + chapterNo=null。
+  appendMessages?: (turn: AiTurnInput) => void;
+  logChapterNo?: number | null;
 }
 
 // 声明驱动的通用生成器（核心）：按 descriptor.input_fields 渲染表单 → 调通用 generate →
@@ -47,6 +53,8 @@ export function GeneratorRunner({
   onClose,
   onInsertText,
   manuscriptText,
+  appendMessages,
+  logChapterNo,
 }: GeneratorRunnerProps) {
   const gen = useGenerator();
   const toast = useToast();
@@ -55,6 +63,8 @@ export function GeneratorRunner({
   );
   // 入库勾选：预览行下标集合（与 gen.rawPreview 行对齐）。
   const [selected, setSelected] = useState<Set<number>>(new Set());
+  // 本 runner 一次会话 = 一个 thread；多次生成归此组。
+  const threadId = useRef(crypto.randomUUID()).current;
 
   const setField = useCallback((name: string, value: string): void => {
     setValues((prev) => ({ ...prev, [name]: value }));
@@ -99,8 +109,36 @@ export function GeneratorRunner({
       return;
     }
     setSelected(new Set());
-    await gen.generate(projectId, tool.key, buildGenerateRequest(values));
-  }, [gen, projectId, tool, values, toast]);
+    const artifact = await gen.generate(
+      projectId,
+      tool.key,
+      buildGenerateRequest(values),
+    );
+    // 留痕（成功且有可读预览时）：author(字段摘要) + ai(渲染预览)；空产物/错误路径不记。
+    if (artifact && appendMessages) {
+      const aiText = renderPreviewText(artifact.preview);
+      if (aiText.length > 0) {
+        appendMessages({
+          threadId,
+          kind: "generator",
+          toolKey: tool.key,
+          chapterNo: logChapterNo ?? null,
+          messages: [
+            {
+              role: "author",
+              content: fieldSummary(tool.input_fields ?? [], values) || tool.title,
+              meta: { tool_key: tool.key, input_fields: values },
+            },
+            {
+              role: "ai",
+              content: aiText,
+              meta: { tool_key: tool.key, output_kind: artifact.outputKind },
+            },
+          ],
+        });
+      }
+    }
+  }, [gen, projectId, tool, values, toast, appendMessages, logChapterNo, threadId]);
 
   const rows = useMemo(
     () => previewRows(gen.rawPreview),

apps/web/components/toolbox/ToolboxPage.tsx

@@ -9,6 +9,7 @@ import { EmptyState } from "@/components/ui/EmptyState";
 import { PageHeader } from "@/components/ui/PageHeader";
 import type { ProjectResponse, ToolDescriptorView } from "@/lib/api/types";
 import { isLegacyTool, resolveLegacyRoute } from "@/lib/toolbox/toolbox";
+import { useAiConversation } from "@/lib/workbench/useAiConversation";
 import { ToolCard } from "./ToolCard";
 import { GeneratorRunner } from "./GeneratorRunner";
 
@@ -27,6 +28,8 @@ export function ToolboxPage({
   initialOpenKey,
 }: ToolboxPageProps) {
   const router = useRouter();
+  // 工具箱页无抽屉：silent 直投——项目级(chapter_no=null)留痕，不 GET、失败不 toast。
+  const conversation = useAiConversation(project.id, 0, { silent: true });
 
   const findOpenable = useCallback(
     (key: string | undefined): ToolDescriptorView | null => {
@@ -76,6 +79,8 @@ export function ToolboxPage({
           <GeneratorRunner
             projectId={project.id}
             tool={active}
+            appendMessages={conversation.appendMessages}
+            logChapterNo={null}
             onClose={() => setActive(null)}
           />
         ) : sorted.length === 0 ? (

apps/web/components/workbench/ChapterRewritePanel.tsx

@@ -1,6 +1,6 @@
 "use client";
 
-import { useState } from "react";
+import { useRef, useState } from "react";
 import { Check, MessagesSquare, RotateCcw, Square, X } from "lucide-react";
 
 import { ThinkingIndicator } from "@/components/ThinkingIndicator";
@@ -12,6 +12,10 @@ import { friendlyError } from "@/lib/errors/messages";
 import { foldClarifications, needsClarifyGate } from "@/lib/workbench/clarify";
 import { useChapterRewrite } from "@/lib/workbench/useChapterRewrite";
 import { useRewriteClarify } from "@/lib/workbench/useRewriteClarify";
+import type {
+  AiTurnInput,
+  AiTurnMessage,
+} from "@/lib/workbench/useAiConversation";
 import { ChoiceChips } from "./ChoiceChips";
 
 // 门控阈值：整章意见 trim 后短于此字数才自动预检反问（清晰意见不交往返税）。
@@ -24,6 +28,8 @@ interface ChapterRewritePanelProps {
   currentDraft: string;
   // 接受某一版 → 替换整章正文（HITL，作者显式点选才落草稿）。
   onAccept: (text: string) => void;
+  // 留痕：每版重写记 [author(折后意见), ai(版本正文)]，含缓冲的 clarify Q&A；同 thread 迭代。
+  appendMessages: (turn: AiTurnInput) => void;
   onClose: () => void;
 }
 
@@ -34,12 +40,16 @@ export function ChapterRewritePanel({
   chapterNo,
   currentDraft,
   onAccept,
+  appendMessages,
   onClose,
 }: ChapterRewritePanelProps) {
   const rewrite = useChapterRewrite();
   const clarify = useRewriteClarify();
   const [feedback, setFeedback] = useState("");
   const [pendingFeedback, setPendingFeedback] = useState<string | null>(null);
+  // 本面板一次会话 = 一个 thread；多版迭代 + 澄清往复归此组，版本号本地累加。
+  const threadId = useRef(crypto.randomUUID()).current;
+  const versionNoRef = useRef(0);
 
   const hasVersions = rewrite.versions.length > 0;
   const clarifying = clarify.status === "checking";
@@ -51,12 +61,34 @@ export function ChapterRewritePanel({
   const priorDraft = rewrite.latest?.text ?? currentDraft;
   const err = rewrite.state.phase === "error" ? rewrite.state.error : null;
 
-  // 折入澄清答案（或原意见）后流式重写，并清理澄清态。
-  const runSend = (fb: string): void => {
+  // 折入澄清答案（或原意见）后流式重写，结束后留痕；clarifyTurns 非空时把缓冲 Q&A 一并落库。
+  const runSend = (fb: string, clarifyTurns: AiTurnMessage[] | null): void => {
     clarify.reset();
     setPendingFeedback(null);
     setFeedback("");
-    void rewrite.send(projectId, chapterNo, fb, priorDraft);
+    void (async () => {
+      const v = await rewrite.send(projectId, chapterNo, fb, priorDraft);
+      if (!v) return; // 停止/失败/空版：不留痕。
+      versionNoRef.current += 1;
+      const versionNo = versionNoRef.current;
+      const aiRow: AiTurnMessage = {
+        role: "ai",
+        content: v.text,
+        meta: { version_no: versionNo },
+      };
+      // clarify 分支：作者答复 IS 本轮 author 输入；否则记 author(折后意见, meta{version_no})。
+      const messages = clarifyTurns
+        ? [...clarifyTurns, aiRow]
+        : [
+            {
+              role: "author" as const,
+              content: fb,
+              meta: { version_no: versionNo },
+            },
+            aiRow,
+          ];
+      appendMessages({ threadId, kind: "rewrite", chapterNo, messages });
+    })();
   };
 
   // 「重写整章 / 再改一版」：意见含糊/极短（或 force）先预检反问；否则直接流式重写。
@@ -70,14 +102,32 @@ export function ChapterRewritePanel({
         return;
       }
     }
-    runSend(fb);
+    runSend(fb, null);
   };
 
-  // 作者答复澄清（点选 value 或自由输入）→ 折进意见 → 流式重写。
+  // 作者答复澄清（点选 value 或自由输入）→ 缓冲 Q&A（原意见→反问→答复）+ 折进意见 → 流式重写。
   const onClarifyAnswer = (answer: string): void => {
-    const question = clarify.decision?.questions[0]?.question ?? "";
+    const q = clarify.decision?.questions[0];
+    const question = q?.question ?? "";
     const base = pendingFeedback ?? feedback.trim();
-    runSend(foldClarifications(base, [{ question, answer }]));
+    const clarifyTurns: AiTurnMessage[] = [
+      { role: "author", content: base },
+      {
+        role: "ai",
+        content: question,
+        meta: {
+          parent_kind: "rewrite",
+          options: (q?.options ?? []).map((o) => ({
+            label: o.label,
+            value: o.value,
+          })),
+          allow_free_text: q?.allowFreeText ?? false,
+          verification: clarify.decision?.verification ?? "",
+        },
+      },
+      { role: "author", content: answer },
+    ];
+    runSend(foldClarifications(base, [{ question, answer }]), clarifyTurns);
   };
 
   return (

apps/web/components/workbench/ContinuePanel.tsx

@@ -1,6 +1,6 @@
 "use client";
 
-import { useEffect, useRef } from "react";
+import { useCallback, useEffect, useRef } from "react";
 import { Check, Plus, X } from "lucide-react";
 
 import { ThinkingIndicator } from "@/components/ThinkingIndicator";
@@ -8,12 +8,15 @@ import { Button } from "@/components/ui/Button";
 import { SectionHeader } from "@/components/ui/SectionHeader";
 import { StatusNote } from "@/components/ui/StatusNote";
 import { useContinue } from "@/lib/workbench/useContinue";
+import type { AiTurnInput } from "@/lib/workbench/useAiConversation";
 
 interface ContinuePanelProps {
   projectId: string;
   chapterNo: number;
   // 插入选中候选到正文（追加到章末）。
   onInsert: (text: string) => void;
+  // 留痕：每条候选记一条 ai 气泡（续写无作者输入，故无 author 气泡）。
+  appendMessages: (turn: AiTurnInput) => void;
   onClose: () => void;
 }
 
@@ -23,16 +26,37 @@ export function ContinuePanel({
   projectId,
   chapterNo,
   onInsert,
+  appendMessages,
   onClose,
 }: ContinuePanelProps) {
   const { status, candidates, generate } = useContinue();
   const ranRef = useRef(false);
+  // 本面板一次会话 = 一个 thread；多条候选归此组，candidate_index 本地累加。
+  const threadId = useRef(crypto.randomUUID()).current;
+  const candidateIdxRef = useRef(0);
+
+  // 生成一条候选并（成功时）留痕：ai-only，meta 存候选序号。
+  const runGenerate = useCallback(async (): Promise<void> => {
+    const text = await generate(projectId, chapterNo);
+    if (!text) return;
+    const candidateIndex = candidateIdxRef.current;
+    candidateIdxRef.current += 1;
+    appendMessages({
+      threadId,
+      kind: "continue",
+      toolKey: "continue",
+      chapterNo,
+      messages: [
+        { role: "ai", content: text, meta: { candidate_index: candidateIndex } },
+      ],
+    });
+  }, [generate, projectId, chapterNo, appendMessages, threadId]);
 
   useEffect(() => {
     if (ranRef.current) return;
     ranRef.current = true;
-    void generate(projectId, chapterNo);
-  }, [projectId, chapterNo, generate]);
+    void runGenerate();
+  }, [runGenerate]);
 
   const busy = status === "generating";
 
@@ -58,7 +82,7 @@ export function ContinuePanel({
         <StatusNote variant="danger" className="mt-3 text-xs" title="续写失败">
           <button
             type="button"
-            onClick={() => void generate(projectId, chapterNo)}
+            onClick={() => void runGenerate()}
             className="mt-1 inline-flex items-center gap-1 text-cinnabar hover:underline"
           >
             重试
@@ -90,7 +114,7 @@ export function ContinuePanel({
 
       <div className="mt-3">
         <Button
-          onClick={() => void generate(projectId, chapterNo)}
+          onClick={() => void runGenerate()}
           disabled={busy}
           variant="secondary"
           size="sm"

apps/web/components/workbench/InlineToolbox.tsx

@@ -11,11 +11,16 @@ import { GeneratorRunner } from "@/components/toolbox/GeneratorRunner";
 import type { ToolDescriptorView } from "@/lib/api/types";
 import { isLegacyTool } from "@/lib/toolbox/toolbox";
 import { useToolboxTools } from "@/lib/toolbox/useToolboxTools";
+import type { AiTurnInput } from "@/lib/workbench/useAiConversation";
 
 interface InlineToolboxProps {
   projectId: string;
+  // 当前章号：内联工具箱生成留痕挂本章（chapter_no=current）。
+  chapterNo: number;
   // 把生成结果插入正文（追加到章末）。
   onInsertText: (text: string) => void;
+  // 留痕：生成成功后 append 一批（透传给 GeneratorRunner）。
+  appendMessages: (turn: AiTurnInput) => void;
   // 当前正文（编辑器 text）。透传给 GeneratorRunner，供 book-title 等据正文反推 brief。
   manuscriptText?: string;
   onClose: () => void;
@@ -26,7 +31,9 @@ interface InlineToolboxProps {
 // 人设/大纲）仍走各自更丰富的独立页，不塞进内联面板。
 export function InlineToolbox({
   projectId,
+  chapterNo,
   onInsertText,
+  appendMessages,
   manuscriptText,
   onClose,
 }: InlineToolboxProps) {
@@ -52,6 +59,8 @@ export function InlineToolbox({
             projectId={projectId}
             tool={active}
             manuscriptText={manuscriptText}
+            appendMessages={appendMessages}
+            logChapterNo={chapterNo}
             onClose={() => setActive(null)}
             onInsertText={(text) => {
               if (text.trim().length > 0) onInsertText(text);

apps/web/components/workbench/RefinePanel.tsx

@@ -11,6 +11,10 @@ import { TextArea } from "@/components/ui/TextArea";
 import { useRefine } from "@/lib/workbench/useRefine";
 import { useClarify } from "@/lib/workbench/useClarify";
 import { foldClarifications, needsClarifyGate } from "@/lib/workbench/clarify";
+import type {
+  AiTurnInput,
+  AiTurnMessage,
+} from "@/lib/workbench/useAiConversation";
 import { ChoiceChips } from "./ChoiceChips";
 
 // 门控阈值：再沟通意见 trim 后短于此字数才自动预检反问（清晰意见不交往返税）。
@@ -23,6 +27,8 @@ interface RefinePanelProps {
   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;
+  // 留痕：把本轮往复（含缓冲的 clarify Q&A）作为一批 append（fail-soft，不阻塞回炉）。
+  appendMessages: (turn: AiTurnInput) => void;
   onClose: () => void;
 }
 
@@ -33,6 +39,7 @@ export function RefinePanel({
   chapterNo,
   original,
   onAccept,
+  appendMessages,
   onClose,
 }: RefinePanelProps) {
   const { status, versions, latest, refine, recommunicate } = useRefine();
@@ -40,12 +47,36 @@ export function RefinePanel({
   const [instruction, setInstruction] = useState("");
   const [pendingInstruction, setPendingInstruction] = useState<string | null>(null);
   const ranRef = useRef(false);
+  // 本面板一次会话 = 一个 thread；所有润色/再沟通/澄清往复归此组。版本号 repo 无关，本地累加。
+  const threadId = useRef(crypto.randomUUID()).current;
+  const versionNoRef = useRef(0);
 
-  // 打开即对选段回炉一次（仅一次，避免重复请求）。
+  // 一版 ai 产出气泡：content=产出，meta 存版本号 + 原选段（每版都存，供任意版 re-accept 重锚）。
+  const aiRow = (refined: string): AiTurnMessage => {
+    versionNoRef.current += 1;
+    return {
+      role: "ai",
+      content: refined,
+      meta: { version_no: versionNoRef.current, segment: original },
+    };
+  };
+
+  // 打开即对选段回炉一次（仅一次，避免重复请求）；成功后留痕 [author(原选段), ai(润色)]。
   useEffect(() => {
     if (ranRef.current) return;
     ranRef.current = true;
-    void refine(projectId, chapterNo, original);
+    void (async () => {
+      const v = await refine(projectId, chapterNo, original);
+      if (v) {
+        appendMessages({
+          threadId,
+          kind: "refine",
+          chapterNo,
+          messages: [{ role: "author", content: original }, aiRow(v.refined)],
+        });
+      }
+    })();
+    // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [projectId, chapterNo, original, refine]);
 
   const busy = status === "refining";
@@ -53,12 +84,23 @@ export function RefinePanel({
   const firstQuestion = clarify.decision?.questions[0] ?? null;
   const asking = clarify.status === "asking" && firstQuestion !== null;
 
-  // 折入澄清答案（或原意见）后回炉，并清理澄清态。
-  const runRecommunicate = (finalInstruction: string): void => {
+  // 折入澄清答案（或原意见）后回炉，结束后留痕；clarifyTurns 非空时把缓冲的 Q&A 一并落库。
+  const runRecommunicate = (
+    finalInstruction: string,
+    clarifyTurns: AiTurnMessage[] | null,
+  ): void => {
     clarify.reset();
     setPendingInstruction(null);
     setInstruction("");
-    void recommunicate(projectId, chapterNo, finalInstruction);
+    void (async () => {
+      const v = await recommunicate(projectId, chapterNo, finalInstruction);
+      if (!v) return;
+      // clarify 分支：作者答复 IS 本轮 author 输入，不再另加 author(意见) 气泡；否则记 author(意见)。
+      const messages = clarifyTurns
+        ? [...clarifyTurns, aiRow(v.refined)]
+        : [{ role: "author" as const, content: finalInstruction }, aiRow(v.refined)];
+      appendMessages({ threadId, kind: "refine", chapterNo, messages });
+    })();
   };
 
   // 「再改一版」：意见含糊/极短（或 force）先预检反问；否则直接回炉。
@@ -73,14 +115,33 @@ export function RefinePanel({
         return;
       }
     }
-    runRecommunicate(trimmed);
+    runRecommunicate(trimmed, null);
   };
 
-  // 作者答复澄清（点选 value 或自由输入）→ 折进意见 → 回炉。
+  // 作者答复澄清（点选 value 或自由输入）→ 缓冲 Q&A（原意见→反问→答复）+ 折进意见 → 回炉。
   const onClarifyAnswer = (answer: string): void => {
-    const question = clarify.decision?.questions[0]?.question ?? "";
+    const q = clarify.decision?.questions[0];
+    const question = q?.question ?? "";
     const base = pendingInstruction ?? instruction.trim();
-    runRecommunicate(foldClarifications(base, [{ question, answer }]));
+    // 缓冲三条：原含糊意见(author) → AI 反问(ai, 选项进 meta) → 作者答复(author)，随本轮产出一起落库。
+    const clarifyTurns: AiTurnMessage[] = [
+      { role: "author", content: base },
+      {
+        role: "ai",
+        content: question,
+        meta: {
+          parent_kind: "refine",
+          options: (q?.options ?? []).map((o) => ({
+            label: o.label,
+            value: o.value,
+          })),
+          allow_free_text: q?.allowFreeText ?? false,
+          verification: clarify.decision?.verification ?? "",
+        },
+      },
+      { role: "author", content: answer },
+    ];
+    runRecommunicate(foldClarifications(base, [{ question, answer }]), clarifyTurns);
   };
 
   return (

apps/web/components/workbench/Workbench.tsx

@@ -9,6 +9,7 @@ import {
   ClipboardCheck,
   FileText,
   Library,
+  MessagesSquare,
   PanelLeft,
   PanelRight,
   PenLine,
@@ -51,9 +52,14 @@ import { ContinuePanel } from "./ContinuePanel";
 import { InlineToolbox } from "./InlineToolbox";
 import { ChapterRewritePanel } from "./ChapterRewritePanel";
 import { ContextDrawer, CONTEXT_DRAWER_ENABLED } from "./ContextDrawer";
+import {
+  AiConversationDrawer,
+  AI_CONVERSATION_ENABLED,
+} from "./AiConversationDrawer";
 import { GenrePicker } from "./GenrePicker";
 import { GENRES } from "@/lib/wizard/wizard";
 import { useGenreGate, toGenreDirective } from "@/lib/workbench/useGenreGate";
+import { useAiConversation } from "@/lib/workbench/useAiConversation";
 
 interface WorkbenchProps {
   project: ProjectResponse;
@@ -96,6 +102,10 @@ export function Workbench({
   const [genrePromptOpen, setGenrePromptOpen] = useState(false);
   // WFW-6 上下文速查抽屉：加法式、flag 灰度；与三张 AI 结果卡互不干扰。
   const [contextOpen, setContextOpen] = useState(false);
+  // AC-3 AI 对话抽屉：Workbench 级单实例（append 即使抽屉关着也能触发）；flag 灰度。
+  const [conversationOpen, setConversationOpen] = useState(false);
+  const conversation = useAiConversation(project.id, chapterNo);
+  const conversationTriggerRef = useRef<HTMLButtonElement>(null);
   const toast = useToast();
   const autosave = useAutosave(project.id, chapterNo, initialText);
   const stream = useDraftStream();
@@ -225,6 +235,37 @@ export function Workbench({
     setContinueOpen(false);
   };
 
+  // 从「AI 对话」历史再接受（复用 DRAFT-only HITL：只回填编辑器草稿，不绕开验收事务——不变量 #3）。
+  // 返回 true=成功则抽屉自关，露出改动后的编辑器 + 成功 toast；refine 找不到原选段返回 false + 漂移提示。
+  const onReplaceChapterFromHistory = (content: string): boolean => {
+    setText(content);
+    autosave.onChange(content);
+    toast("已替换整章。", "success");
+    return true;
+  };
+
+  const onAppendDraftFromHistory = (content: string): boolean => {
+    appendToDraft(content);
+    toast("已插入正文。", "success");
+    return true;
+  };
+
+  const onRefillSegmentFromHistory = (
+    segment: string,
+    refined: string,
+  ): boolean => {
+    // 合成零区间强制 slice 校验失败 → 走 indexOf 按存档的原选段重锚；找不到则不盲替换。
+    const next = applyRefinement(text, segment, refined, { start: 0, end: 0 });
+    if (next === null) {
+      toast("正文已改动，找不到原选段，无法回填。", "error");
+      return false;
+    }
+    setText(next);
+    autosave.onChange(next);
+    toast("已回填选段。", "success");
+    return true;
+  };
+
   // 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);
@@ -288,6 +329,7 @@ export function Workbench({
               chapterNo={chapterNo}
               original={selection.text}
               onAccept={onAcceptRefine}
+              appendMessages={conversation.appendMessages}
               onClose={() => setRefineOpen(false)}
             />
           ) : null}
@@ -296,13 +338,16 @@ export function Workbench({
               projectId={project.id}
               chapterNo={chapterNo}
               onInsert={onInsertContinuation}
+              appendMessages={conversation.appendMessages}
               onClose={() => setContinueOpen(false)}
             />
           ) : null}
           {toolboxOpen ? (
             <InlineToolbox
               projectId={project.id}
+              chapterNo={chapterNo}
               manuscriptText={text}
+              appendMessages={conversation.appendMessages}
               onInsertText={(chunk) => {
                 appendToDraft(chunk);
                 setToolboxOpen(false);
@@ -316,6 +361,7 @@ export function Workbench({
               chapterNo={chapterNo}
               currentDraft={text}
               onAccept={onAcceptRewrite}
+              appendMessages={conversation.appendMessages}
               onClose={() => setRewriteOpen(false)}
             />
           ) : null}
@@ -350,6 +396,8 @@ export function Workbench({
             onRewrite={openRewrite}
             onOpenContext={() => setContextOpen(true)}
             contextTriggerRef={contextTriggerRef}
+            onOpenConversation={() => setConversationOpen(true)}
+            conversationTriggerRef={conversationTriggerRef}
           />
         </section>
 
@@ -387,6 +435,20 @@ export function Workbench({
         onClose={() => setContextOpen(false)}
         triggerRef={contextTriggerRef}
       />
+
+      {/* AC-3 AI 对话：右侧 slide-over 气泡视图；从历史再接受只回填草稿，不绕验收事务。flag 灰度。 */}
+      {AI_CONVERSATION_ENABLED ? (
+        <AiConversationDrawer
+          open={conversationOpen}
+          onClose={() => setConversationOpen(false)}
+          conversation={conversation}
+          currentChapterNo={chapterNo}
+          onReplaceChapter={onReplaceChapterFromHistory}
+          onAppendDraft={onAppendDraftFromHistory}
+          onRefillSegment={onRefillSegmentFromHistory}
+          triggerRef={conversationTriggerRef}
+        />
+      ) : null}
     </AppShell>
   );
 }
@@ -585,6 +647,9 @@ interface ToolbarProps {
   // 打开上下文速查抽屉（WFW-6）。
   onOpenContext: () => void;
   contextTriggerRef: RefObject<HTMLButtonElement | null>;
+  // 打开 AI 对话抽屉（AC-3）。
+  onOpenConversation: () => void;
+  conversationTriggerRef: RefObject<HTMLButtonElement | null>;
 }
 
 function Toolbar({
@@ -605,6 +670,8 @@ function Toolbar({
   onRewrite,
   onOpenContext,
   contextTriggerRef,
+  onOpenConversation,
+  conversationTriggerRef,
 }: 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">
@@ -681,6 +748,18 @@ function Toolbar({
             速查
           </Button>
         ) : null}
+        {AI_CONVERSATION_ENABLED ? (
+          <Button
+            ref={conversationTriggerRef}
+            onClick={onOpenConversation}
+            variant="secondary"
+            size="sm"
+            title="打开 AI 对话（润色/重写/续写/工具箱往复留痕）"
+          >
+            <MessagesSquare className="h-4 w-4" aria-hidden="true" />
+            AI 对话
+          </Button>
+        ) : null}
         <Link
           href={`/projects/${projectId}/outline`}
           className={buttonClass({ variant: "secondary", size: "sm" })}