diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index 5cbc3d4..63bfe41 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -48,6 +48,7 @@ import {
   labels,
   roleLabels,
   type Analysis,
+  type AssistantReply,
   type Context,
   type Dataset,
   type FormulaColumn,
@@ -514,6 +515,9 @@ export function App() {
   if (!session.user) return <Login onLogin={loadSession} />;
   const user = session.user;
   const canUpload = user.role !== "viewer" && !user.departments.length;
+  const canDesign =
+    (user.role === "admin" || user.role === "analyst") &&
+    !user.departments.length;
   return (
     <div className="app">
       <aside className={`sidebar ${mobileNav ? "open" : ""}`}>
@@ -1428,15 +1432,29 @@ export function App() {
           ds={ds}
           ctx={ctx}
           ai={session.ai_enabled}
+          canDesign={canDesign}
           onClose={() => setChat(false)}
-          onApply={(reply) => {
-            setCtx(reply.context);
+          onApply={(reply: AssistantReply) => {
+            // 普通回答与列设计不改变页面；只有显式查询动作才导航。
+            if (reply.kind === "column_design" || !reply.context) return;
+            if (
+              !["overview", "anomalies", "drill", "evidence"].includes(
+                reply.intent?.action,
+              )
+            )
+              return;
+            const next: Context = {
+              ...reply.context,
+              custom_columns:
+                reply.context?.custom_columns ?? ctx.custom_columns,
+            };
+            setCtx(next);
             setPath(
-              Object.entries(reply.context.filters).map(
+              Object.entries(next.filters).map(
                 ([key, value], index, entries) => ({
                   label: value,
                   ctx: {
-                    ...reply.context,
+                    ...next,
                     group: key,
                     filters: Object.fromEntries(entries.slice(0, index)),
                   },
@@ -1450,8 +1468,17 @@ export function App() {
                   ? "anomalies"
                   : "investigate",
             );
-            if (reply.intent.action === "evidence")
-              setEvidenceCtx(reply.context);
+            if (reply.intent.action === "evidence") setEvidenceCtx(next);
+          }}
+          onColumnsApplied={(columns: FormulaColumn[]) => {
+            setCtx((current) =>
+              current ? { ...current, custom_columns: columns } : current,
+            );
+            api<{ items: SavedFormulaDefinition[] }>(
+              `/datasets/${ds.id}/formula-definitions`,
+            )
+              .then((data) => setFormulaDefinitions(data.items))
+              .catch(report);
           }}
         />
       )}
diff --git a/frontend/src/dialogs.tsx b/frontend/src/dialogs.tsx
index ead1367..0f4603a 100644
--- a/frontend/src/dialogs.tsx
+++ b/frontend/src/dialogs.tsx
@@ -12,6 +12,10 @@ import {
   labels,
   roleLabels,
   type AIConfig,
+  type AssistantDesign,
+  type AssistantMessage,
+  type AssistantMode,
+  type AssistantReply,
   type Context,
   type Dataset,
   type FormulaColumn,
@@ -24,6 +28,67 @@ import {
 
 type User = NonNullable<Session["user"]>;
 
+interface ChatMessage {
+  role: "user" | "assistant";
+  content: string;
+  history?: string;
+  source?: "model" | "rules";
+  model?: string | null;
+}
+
+const navigationActions = new Set([
+  "overview",
+  "anomalies",
+  "drill",
+  "evidence",
+]);
+
+function scopeKeyOf(ds: Dataset, ctx: Context) {
+  return [
+    ds.id,
+    ds.version,
+    ctx.start,
+    ctx.end,
+    ctx.baseline_end || "",
+    ctx.comparison,
+    ctx.group,
+    ctx.metric,
+    JSON.stringify(Object.entries(ctx.filters || {}).sort()),
+  ].join("|");
+}
+
+// 只提交已完成的 user→assistant 轮次，最多 5 轮，当前问题不进入 history。
+function completedHistory(messages: ChatMessage[]): AssistantMessage[] {
+  const history: AssistantMessage[] = [];
+  for (let index = 0; index + 1 < messages.length; index += 2) {
+    const user = messages[index];
+    const assistant = messages[index + 1];
+    if (user.role === "user" && assistant.role === "assistant")
+      history.push(
+        { role: "user", content: user.content },
+        {
+          role: "assistant",
+          content: assistant.history || assistant.content,
+        },
+      );
+  }
+  return history.slice(-10);
+}
+
+function replyContent(reply: AssistantReply) {
+  const answer = (reply.answer || "").trim();
+  if (reply.kind !== "column_design") return answer || "本轮没有返回内容。";
+  const questions = (reply.design?.questions || [])
+    .map((question) => question.trim())
+    .filter(Boolean);
+  if (
+    questions.length &&
+    !questions.every((question) => answer.includes(question))
+  )
+    return [answer, questions.join("\n")].filter(Boolean).join("\n");
+  return answer || "请补充列名、计算含义和适用范围。";
+}
+
 function describeExpression(expression: FormulaExpression): string {
   if ("metric" in expression) return labels[expression.metric];
   if ("number" in expression) return String(expression.number);
@@ -796,57 +861,374 @@ export function Copilot({
   ds,
   ctx,
   ai,
+  canDesign,
   onClose,
   onApply,
+  onColumnsApplied,
 }: {
   ds: Dataset;
   ctx: Context;
   ai: boolean;
+  canDesign: boolean;
   onClose: () => void;
-  onApply: (reply: { context: Context; intent: { action: string } }) => void;
+  onApply: (reply: AssistantReply) => void;
+  onColumnsApplied: (columns: FormulaColumn[]) => void;
 }) {
   const [question, setQuestion] = useState(""),
     [consent, setConsent] = useState(false),
     [useModel, setUseModel] = useState(false),
-    [answer, setAnswer] = useState(""),
+    [mode, setMode] = useState<AssistantMode>("auto"),
+    [messages, setMessages] = useState<ChatMessage[]>([]),
+    [inFlight, setInFlight] = useState<string>(""),
+    [design, setDesign] = useState<AssistantDesign | null>(null),
+    [notice, setNotice] = useState(""),
     [error, setError] = useState(""),
-    [busy, setBusy] = useState(false);
+    [busy, setBusy] = useState(false),
+    [saving, setSaving] = useState(false);
+  const epoch = useRef(0);
+  const savingRef = useRef(false);
+  const scopeRef = useRef<string | null>(null);
+  const listRef = useRef<HTMLDivElement>(null);
+  const inputRef = useRef<HTMLTextAreaElement>(null);
+  const currentScope = scopeKeyOf(ds, ctx);
+  const completedTurns = messages.filter((item) => item.role === "user").length;
+  const limitReached = completedTurns >= 6;
+  const canSend =
+    !busy &&
+    !saving &&
+    !!question.trim() &&
+    !limitReached &&
+    (!useModel || consent) &&
+    (mode !== "column_design" || (useModel && consent));
+
+  useEffect(() => {
+    if (scopeRef.current === currentScope) return;
+    const initial = scopeRef.current === null;
+    scopeRef.current = currentScope;
+    if (initial) return;
+    // 数据/范围/映射版本变化：历史与待确认定义立即失效，迟到响应按 epoch 丢弃。
+    epoch.current += 1;
+    savingRef.current = false;
+    setBusy(false);
+    setSaving(false);
+    setInFlight("");
+    setMessages([]);
+    setDesign(null);
+    setMode("auto");
+    setError("");
+    setNotice("数据范围已变更，已开始新的对话。");
+  }, [currentScope]);
+
+  useEffect(() => {
+    const list = listRef.current;
+    if (list) list.scrollTop = list.scrollHeight;
+  }, [messages, inFlight, design, notice, error]);
+
   async function submit(event: React.FormEvent) {
     event.preventDefault();
+    const text = question.trim();
+    if (!canSend) return;
+    const nextMode: AssistantMode = useModel ? mode : "auto";
+    const history = completedHistory(messages);
+    const ticket = ++epoch.current;
     setBusy(true);
     setError("");
+    setNotice("");
+    // 新消息立即让旧预览失效。
+    setDesign(null);
+    setInFlight(text);
     try {
-      const r = await api<{
-        answer: string;
-        context: Context;
-        intent: { action: string };
-      }>(`/datasets/${ds.id}/assistant`, "POST", {
-        question,
-        context: ctx,
-        use_model: useModel,
-        consent,
-      });
-      setAnswer(r.answer);
-      onApply(r);
+      const reply = await api<AssistantReply>(
+        `/datasets/${ds.id}/assistant`,
+        "POST",
+        {
+          question: text,
+          context: ctx,
+          use_model: useModel,
+          consent,
+          history,
+          mode: nextMode,
+        },
+      );
+      if (ticket !== epoch.current) return;
+      const assistantContent = replyContent(reply);
+      // 完整列定义进入后续对话历史，便于“继续修改”沿用上一版口径。
+      const historyContent =
+        reply.kind === "column_design" && reply.design?.column
+          ? `${assistantContent}\n列定义：${JSON.stringify(reply.design.column)}`
+          : undefined;
+      setMessages((items) => [
+        ...items,
+        { role: "user", content: text },
+        {
+          role: "assistant",
+          content: assistantContent,
+          history: historyContent,
+          source: reply.source,
+          model: reply.model,
+        },
+      ]);
+      if (reply.kind === "column_design") {
+        setMode("column_design");
+        setDesign(reply.design || null);
+        if (!reply.design)
+          setNotice("列设计未返回可用预览，请补充描述后重试。");
+      } else {
+        setMode(nextMode === "column_design" ? "auto" : mode);
+        setDesign(null);
+      }
+      setQuestion((current) => (current === text ? "" : current));
+      if (
+        navigationActions.has(reply.intent?.action) &&
+        reply.context &&
+        scopeKeyOf(ds, reply.context) !== currentScope
+      ) {
+        // 本轮由助手主动更新范围，保留刚生成的回答；页面变化由 App 应用。
+        scopeRef.current = scopeKeyOf(ds, reply.context);
+      }
+      onApply(reply);
     } catch (e) {
-      setError((e as Error).message);
+      if (ticket === epoch.current) setError((e as Error).message);
     } finally {
-      setBusy(false);
+      if (ticket === epoch.current) {
+        setBusy(false);
+        setInFlight("");
+      }
     }
   }
+
+  function newConversation() {
+    epoch.current += 1;
+    savingRef.current = false;
+    setMessages([]);
+    setDesign(null);
+    setInFlight("");
+    setMode("auto");
+    setBusy(false);
+    setSaving(false);
+    setError("");
+    setNotice("已开始新对话。");
+  }
+
+  function exitDesign() {
+    setMode("auto");
+    setDesign(null);
+    setNotice("已退出列设计，可继续普通问答。");
+    inputRef.current?.focus();
+  }
+
+  function continueEditing() {
+    setDesign(null);
+    setNotice("请补充或修改列定义后重新发送。");
+    inputRef.current?.focus();
+  }
+
+  async function confirmDesign() {
+    const column = design?.complete ? design.column : null;
+    if (!column || !canDesign || savingRef.current || busy) return;
+    const nameKey = column.name.trim().toLowerCase();
+    const columns = ctx.custom_columns || [];
+    const position = columns.findIndex(
+      (item) => item.name.trim().toLowerCase() === nameKey,
+    );
+    if (position < 0 && columns.length >= 10) {
+      setError("当前已有 10 个分析列，请先移除一列后再添加。");
+      return;
+    }
+    const ticket = epoch.current;
+    savingRef.current = true;
+    setSaving(true);
+    setError("");
+    setNotice("");
+    try {
+      let definitions: SavedFormulaDefinition[];
+      try {
+        definitions = (
+          await api<{ items: SavedFormulaDefinition[] }>(
+            `/datasets/${ds.id}/formula-definitions`,
+          )
+        ).items;
+      } catch (e) {
+        if (ticket === epoch.current)
+          setError(`无法读取已保存定义：${(e as Error).message}`);
+        return;
+      }
+      if (ticket !== epoch.current) return;
+      const duplicates = definitions.filter(
+        (item) => item.definition.name.trim().toLowerCase() === nameKey,
+      );
+      const shared = duplicates.find((item) => !item.owned);
+      if (shared) {
+        if (ticket === epoch.current)
+          setError(
+            `已存在由 ${shared.owner} 共享的同名列「${shared.definition.name}」，请先更换列名。`,
+          );
+        return;
+      }
+      const owned = duplicates.find((item) => item.owned);
+      const saved = await api<SavedFormulaDefinition>(
+        `/datasets/${ds.id}/formula-definitions`,
+        "POST",
+        {
+          definition: column,
+          ...(owned ? { revision: owned.revision } : {}),
+        },
+      );
+      if (ticket !== epoch.current) return;
+      const latest = ctx.custom_columns || [];
+      const index = latest.findIndex(
+        (item) => item.name.trim().toLowerCase() === nameKey,
+      );
+      if (index < 0 && latest.length >= 10) {
+        setError(
+          `已保存定义「${saved.definition.name}」，但当前分析列已达 10 列，请先移除一列后再确认。`,
+        );
+        return;
+      }
+      const next =
+        index >= 0
+          ? latest.map((item, i) => (i === index ? saved.definition : item))
+          : [...latest, saved.definition];
+      onColumnsApplied(next);
+      setDesign(null);
+      setMode("auto");
+      setNotice(`已添加分析列：${saved.definition.name}，分析结果已刷新。`);
+    } catch (e) {
+      if (ticket === epoch.current)
+        setError(`保存定义失败：${(e as Error).message}`);
+    } finally {
+      if (ticket === epoch.current) {
+        savingRef.current = false;
+        setSaving(false);
+      }
+    }
+  }
+
   return (
-    <aside className="copilot">
+    <aside className="copilot" aria-label="财务分析助手">
       <header>
-        <strong>财务分析助手</strong>
-        <button className="icon" aria-label="关闭" onClick={onClose}>
-          <X />
-        </button>
+        <div className="copilot-title">
+          <strong>财务分析助手</strong>
+          <small>
+            {mode === "column_design" ? "列设计模式" : "普通问答"} · 已完成{" "}
+            {completedTurns}/6 轮
+          </small>
+        </div>
+        <div className="copilot-actions">
+          <button className="ghost" onClick={newConversation}>
+            新对话
+          </button>
+          {mode === "column_design" && (
+            <button className="ghost" disabled={saving} onClick={exitDesign}>
+              退出列设计
+            </button>
+          )}
+          <button className="icon" aria-label="关闭" onClick={onClose}>
+            <X />
+          </button>
+        </div>
       </header>
       <div className="context-tag">
         当前范围：{Object.values(ctx.filters).join(" / ") || "全部"} · {ds.name}
       </div>
-      <div className="chat-messages" aria-live="polite">
-        {answer && <p className="message">{answer}</p>}
+      <div className="chat-messages" aria-live="polite" ref={listRef}>
+        {!messages.length && !inFlight && !design && (
+          <p className="muted">
+            可以询问当前范围的经营问题，或描述要新增的分析列。
+          </p>
+        )}
+        {messages.map((message, index) => (
+          <div
+            key={index}
+            className={message.role === "user" ? "message-user" : "message assistant"}
+          >
+            <strong>{message.role === "user" ? "我" : "助手"}</strong>
+            <p className={message.role === "user" ? "question" : undefined}>
+              {message.content}
+            </p>
+            {message.role === "assistant" && message.source && (
+              <span className="message-source">
+                来源：
+                {message.source === "model"
+                  ? `模型回答 · ${message.model || "未命名模型"}`
+                  : "规则摘要"}
+              </span>
+            )}
+          </div>
+        ))}
+        {inFlight && (
+          <div className="message-user pending">
+            <strong>我</strong>
+            <p className="question">{inFlight}</p>
+            <span className="message-source">发送中…</span>
+          </div>
+        )}
+        {design && (
+          <section className="design-preview" aria-label="列定义预览">
+            {design.complete && design.column ? (
+              <>
+                <h3>{design.column.name}</h3>
+                <p>{design.column.meaning}</p>
+                <dl>
+                  <dt>计算表达式</dt>
+                  <dd>
+                    {describeExpression(
+                      design.column.expression as FormulaExpression,
+                    )}
+                  </dd>
+                  <dt>适用范围</dt>
+                  <dd>{design.column.scope}</dd>
+                  <dt>缺失/零分母</dt>
+                  <dd>{design.column.missing}</dd>
+                </dl>
+                <div className="design-actions">
+                  {canDesign ? (
+                    <button
+                      className="primary"
+                      disabled={saving || busy}
+                      onClick={confirmDesign}
+                    >
+                      {saving ? "添加中…" : "确认并添加分析列"}
+                    </button>
+                  ) : (
+                    <p className="muted">
+                      当前账号无列设计权限，无法添加分析列。
+                    </p>
+                  )}
+                  <button disabled={saving || busy} onClick={continueEditing}>
+                    继续修改
+                  </button>
+                </div>
+                {saving && (
+                  <p role="status" className="muted">
+                    正在保存定义并刷新分析结果…
+                  </p>
+                )}
+              </>
+            ) : (
+              <>
+                <h3>列设计待补充</h3>
+                {design.questions.length ? (
+                  <ul>
+                    {design.questions.map((item, index) => (
+                      <li key={index}>{item}</li>
+                    ))}
+                  </ul>
+                ) : (
+                  <p>请补充列名、计算含义和适用范围。</p>
+                )}
+                <button disabled={saving || busy} onClick={exitDesign}>
+                  退出列设计
+                </button>
+              </>
+            )}
+          </section>
+        )}
+        {notice && (
+          <p role="status" className="notice">
+            {notice}
+          </p>
+        )}
         {error && (
           <p role="alert" className="error">
             {error}
@@ -857,10 +1239,17 @@ export function Copilot({
         <label>
           描述要分析的问题
           <textarea
+            ref={inputRef}
             required
             maxLength={2000}
             value={question}
             onChange={(e) => setQuestion(e.target.value)}
+            onKeyDown={(event) => {
+              if (event.key === "Enter" && (event.metaKey || event.ctrlKey)) {
+                event.preventDefault();
+                event.currentTarget.form?.requestSubmit();
+              }
+            }}
           />
         </label>
         {ai && (
@@ -869,7 +1258,14 @@ export function Copilot({
               <input
                 type="checkbox"
                 checked={useModel}
-                onChange={(e) => setUseModel(e.target.checked)}
+                disabled={busy || saving}
+                onChange={(e) => {
+                  setUseModel(e.target.checked);
+                  if (!e.target.checked) {
+                    setMode("auto");
+                    setDesign(null);
+                  }
+                }}
               />
               使用已配置的 AI 模型理解问题
             </label>
@@ -878,18 +1274,29 @@ export function Copilot({
                 <input
                   type="checkbox"
                   checked={consent}
+                  disabled={busy || saving}
                   onChange={(e) => setConsent(e.target.checked)}
                 />
-                同意发送问题和筛选上下文
+                同意将本次对话、当前筛选、指标定义和权限范围内的汇总分析结果发送到已配置的模型服务
               </label>
             )}
           </>
         )}
-        <button
-          className="primary"
-          disabled={busy || !question.trim() || (useModel && !consent)}
-        >
-          {busy ? "分析中…" : "发送"}
+        {busy && (
+          <p role="status" className="copilot-status">
+            正在分析…
+          </p>
+        )}
+        {limitReached && (
+          <p role="status" className="notice">
+            已达到 6 轮对话上限，请开始新对话。
+          </p>
+        )}
+        {mode === "column_design" && !(useModel && consent) && (
+          <p className="notice">列设计需要启用模型并同意发送。</p>
+        )}
+        <button className="primary" disabled={!canSend}>
+          {busy ? "发送中…" : "发送"}
         </button>
       </form>
     </aside>
diff --git a/frontend/src/style.css b/frontend/src/style.css
index 06ab09a..f6975c5 100644
--- a/frontend/src/style.css
+++ b/frontend/src/style.css
@@ -1204,6 +1204,7 @@ dialog footer > span {
   display: flex;
   align-items: center;
   justify-content: space-between;
+  gap: 10px;
   padding: 17px 18px;
   border-bottom: 1px solid var(--line);
 }
@@ -1211,6 +1212,34 @@ dialog footer > span {
   display: block;
   margin-top: 5px;
 }
+.copilot-title {
+  flex: 1;
+  min-width: 0;
+}
+.copilot-title strong {
+  display: block;
+  overflow-wrap: anywhere;
+}
+.copilot-title small {
+  color: var(--muted);
+  font-size: 10px;
+  line-height: 1.4;
+}
+.copilot-actions {
+  display: flex;
+  align-items: center;
+  justify-content: flex-end;
+  flex-wrap: wrap;
+  gap: 4px;
+}
+.copilot-actions .ghost {
+  min-height: 0;
+  padding: 4px 7px;
+  font-size: 10px;
+}
+.copilot-actions .icon {
+  min-width: 32px;
+}
 .chat-messages {
   flex: 1;
   overflow: auto;
@@ -1232,17 +1261,106 @@ dialog footer > span {
   font-size: 12px;
   margin-bottom: 7px;
 }
-.message {
+.message,
+.message-user {
   padding-block: 10px;
   border-top: 1px solid var(--line);
   font-size: 12px;
   line-height: 1.9;
 }
-.message p {
+.message > strong,
+.message-user > strong {
+  display: block;
+  margin-bottom: 5px;
+  font-size: 10px;
+  color: #7b9282;
+}
+.message.assistant > strong {
+  color: #1d584a;
+}
+.message-user.pending .question {
+  opacity: 0.7;
+}
+.message-source {
+  display: block;
+  margin-top: 6px;
+  font-size: 10px;
+  color: #7b9282;
+  overflow-wrap: anywhere;
+}
+.message-user.pending .message-source {
+  color: #9a7a2e;
+}
+.copilot-status {
+  margin: 0 0 8px;
+  font-size: 10px;
+  color: var(--muted);
+}
+.copilot .notice,
+.copilot .error {
+  margin: 10px 0 0;
+  padding: 8px 10px;
+  font-size: 11px;
+  line-height: 1.6;
+}
+.design-preview {
+  margin-top: 12px;
+  padding: 12px;
+  border: 1px solid var(--line);
+  border-radius: 6px;
+  background: #f8faf9;
+  font-size: 12px;
+  line-height: 1.7;
+}
+.design-preview h3 {
+  margin: 0 0 6px;
+  font-size: 13px;
+  overflow-wrap: anywhere;
+}
+.design-preview p {
+  margin: 0 0 6px;
   white-space: pre-wrap;
   overflow-wrap: anywhere;
 }
-.message .question {
+.design-preview ul {
+  margin: 0 0 8px;
+  padding-left: 18px;
+}
+.design-preview li {
+  margin-bottom: 4px;
+  overflow-wrap: anywhere;
+}
+.design-preview dl {
+  display: grid;
+  grid-template-columns: auto minmax(0, 1fr);
+  gap: 4px 10px;
+  margin: 8px 0 10px;
+}
+.design-preview dt {
+  color: #7b9282;
+}
+.design-preview dd {
+  margin: 0;
+  overflow-wrap: anywhere;
+}
+.design-actions {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 6px;
+}
+.design-actions button {
+  font-size: 11px;
+  white-space: normal;
+  text-align: center;
+}
+.message p,
+.message-user p {
+  white-space: pre-wrap;
+  overflow-wrap: anywhere;
+}
+.message .question,
+.message-user .question {
   background: #e9f2ec;
   padding: 10px 12px;
   border-radius: 5px;
@@ -1258,8 +1376,17 @@ dialog footer > span {
   border-top: 1px solid var(--line);
 }
 .copilot .check {
+  display: flex;
+  align-items: flex-start;
+  gap: 7px;
+  margin: 0 0 10px;
   font-size: 10px;
-  margin-bottom: 10px;
+  line-height: 1.5;
+  white-space: normal;
+}
+.copilot .check input {
+  flex: none;
+  margin-top: 2px;
 }
 .chat-input {
   display: flex;
@@ -1585,6 +1712,15 @@ details {
     width: calc(100% - 20px);
     height: calc(100dvh - 75px);
   }
+  .copilot header {
+    padding: 12px 14px;
+  }
+  .copilot .chat-messages {
+    padding: 14px;
+  }
+  .design-actions button {
+    flex: 1 1 100%;
+  }
   dialog,
   .dialog.wide {
     width: calc(100% - 16px);
diff --git a/frontend/src/types.ts b/frontend/src/types.ts
index 0008087..2452372 100644
--- a/frontend/src/types.ts
+++ b/frontend/src/types.ts
@@ -125,6 +125,34 @@ export interface SavedFormulaDefinition {
   owner: string;
   history: { revision: number; definition: FormulaColumn; updated_at: string }[];
 }
+export interface AssistantMessage {
+  role: "user" | "assistant";
+  content: string;
+}
+export type AssistantMode = "auto" | "column_design";
+export interface AssistantDesign {
+  complete: boolean;
+  questions: string[];
+  column: FormulaColumn | null;
+}
+export interface AssistantIntent {
+  action: string;
+  metric?: Metric;
+  group?: string;
+  filters?: Record<string, string>;
+}
+export interface AssistantReply {
+  answer: string;
+  intent: AssistantIntent;
+  context: Context;
+  version: string;
+  provider: string;
+  evidence?: unknown[];
+  kind: "answer" | "column_design";
+  source: "model" | "rules";
+  model: string | null;
+  design?: AssistantDesign;
+}
 export interface Value {
   current: Numeric;
   baseline: Numeric;
@@ -174,6 +202,8 @@ export interface Session {
     departments: string[];
   } | null;
   ai_enabled: boolean;
+  ai_model?: string | null;
+  ai_provider?: "openai" | "local" | null;
 }
 export const format = (v: Numeric | undefined, metric?: string) =>
   v == null
diff --git a/tests/e2e/assistant.spec.ts b/tests/e2e/assistant.spec.ts
new file mode 100644
index 0000000..e2e6242
--- /dev/null
+++ b/tests/e2e/assistant.spec.ts
@@ -0,0 +1,266 @@
+import { expect, test } from "@playwright/test";
+import type { Page } from "@playwright/test";
+import fs from "node:fs";
+
+const password =
+  process.env.E2E_PASSWORD ||
+  fs.readFileSync("var/local-access.txt", "utf8").match(/密码：(.+)/)![1];
+
+const csv = (customerCode: string) =>
+  `期间,科室,学科,医生等级,医生,产品一级分类,实际收入,成本,毛利贡献,客户编码\n2025-08,测试儿保,普儿,高级,医生A,医疗服务,10000,4000,6000,${customerCode}\n2026-08,测试儿保,普儿,高级,医生A,医疗服务,5000,4000,3000,${customerCode}\n`;
+
+// 模型请求由 route mock，登录、导入、保存定义与查询走真实后端。
+async function forceAiEnabled(page: Page) {
+  await page.route("**/api/session", async (route) => {
+    const response = await route.fetch();
+    const json = await response.json();
+    const headers = Object.fromEntries(
+      Object.entries(response.headers()).filter(
+        ([name]) => name.toLowerCase() !== "content-length",
+      ),
+    );
+    await route.fulfill({
+      status: response.status(),
+      headers,
+      json: { ...json, ai_enabled: true },
+    });
+  });
+}
+
+async function login(page: Page) {
+  await page.goto("/");
+  await page.getByLabel("用户名", { exact: true }).fill("admin");
+  await page.getByLabel("密码", { exact: true }).fill(password);
+  await page.getByRole("button", { name: "登录", exact: true }).click();
+  await expect(page.getByRole("button", { name: "导入新表格" })).toBeVisible();
+}
+
+async function uploadCsv(page: Page) {
+  const uploaded = page.waitForResponse(
+    (response) =>
+      response.url().endsWith("/api/datasets") &&
+      response.request().method() === "POST",
+  );
+  await page.getByLabel("上传财务表格").setInputFiles({
+    name: `assistant-e2e-${Date.now()}.csv`,
+    mimeType: "text/csv",
+    buffer: Buffer.from(csv(`E2E-${Date.now()}`)),
+  });
+  await uploaded;
+  await page
+    .getByRole("dialog", { name: "确认导入字段" })
+    .getByRole("button", { name: "确认并导入" })
+    .click();
+  await expect(
+    page.getByRole("heading", { name: "集团经营总览", exact: true }),
+  ).toBeVisible({ timeout: 60000 });
+}
+
+async function openCopilot(page: Page) {
+  await page.getByRole("button", { name: "Copilot", exact: true }).click();
+  const copilot = page.locator(".copilot");
+  await copilot
+    .getByRole("checkbox", { name: "使用已配置的 AI 模型理解问题" })
+    .check();
+  await copilot.getByRole("checkbox", { name: /同意将本次对话/ }).check();
+  return copilot;
+}
+
+test("动态回答：展示模型标记与实际模型名，普通问答不改变页面", async ({
+  page,
+}) => {
+  await page.setViewportSize({ width: 1512, height: 982 });
+  await forceAiEnabled(page);
+  const requests: Array<Record<string, unknown>> = [];
+  await page.route("**/api/datasets/*/assistant", async (route) => {
+    const payload = route.request().postDataJSON();
+    requests.push(payload);
+    await route.fulfill({
+      json: {
+        answer: "动态分析标记 A：本期收入 5,000，成本 4,000。",
+        intent: {
+          action: "answer",
+          metric: payload.context.metric,
+          group: payload.context.group,
+          filters: payload.context.filters,
+        },
+        context: payload.context,
+        version: "assistant-e2e",
+        provider: "local",
+        evidence: [],
+        kind: "answer",
+        source: "model",
+        model: "deepseek-chat-e2e",
+      },
+    });
+  });
+  await login(page);
+  await uploadCsv(page);
+  const copilot = await openCopilot(page);
+  await copilot.getByLabel("描述要分析的问题").fill("本期收入有哪些变化？");
+  await copilot.getByRole("button", { name: "发送", exact: true }).click();
+
+  await expect(
+    copilot.getByText("动态分析标记 A", { exact: false }),
+  ).toBeVisible();
+  await expect(copilot).toContainText("来源：模型回答 · deepseek-chat-e2e");
+  await expect(
+    page.getByRole("heading", { name: "集团经营总览", exact: true }),
+  ).toBeVisible();
+  await expect(page.getByRole("heading", { name: /异常调查/ })).toHaveCount(0);
+  expect(requests).toHaveLength(1);
+  expect(requests[0]).toMatchObject({
+    question: "本期收入有哪些变化？",
+    use_model: true,
+    consent: true,
+    mode: "auto",
+    history: [],
+  });
+  expect(requests[0].context).toMatchObject({ filters: {} });
+});
+
+test("对话新增列：追问、预览、确认后真实保存并出现列头", async ({ page }) => {
+  await page.setViewportSize({ width: 1600, height: 1000 });
+  await forceAiEnabled(page);
+  const requests: Array<Record<string, unknown>> = [];
+  await page.route("**/api/datasets/*/assistant", async (route) => {
+    const payload = route.request().postDataJSON();
+    requests.push(payload);
+    const first = requests.length === 1;
+    await route.fulfill({
+      json: {
+        answer: first ? "请补充列的定义。" : "已整理列定义。",
+        intent: {
+          action: "design_column",
+          metric: payload.context.metric,
+          group: payload.context.group,
+          filters: payload.context.filters,
+        },
+        context: payload.context,
+        version: "assistant-e2e",
+        provider: "local",
+        evidence: [],
+        kind: "column_design",
+        source: "model",
+        model: "deepseek-chat-e2e",
+        design: first
+          ? {
+              complete: false,
+              questions: ["缺失值和零分母如何处理？"],
+              column: null,
+            }
+          : {
+              complete: true,
+              questions: [],
+              column: {
+                name: "收入成本差",
+                meaning: "实际收入减成本",
+                scope: "所选分组与期间",
+                missing: "结果不可用（#N/A）；零分母不可用",
+                expression: {
+                  operator: "subtract",
+                  left: { metric: "revenue" },
+                  right: { metric: "cost" },
+                },
+              },
+            },
+      },
+    });
+  });
+  await login(page);
+  await uploadCsv(page);
+  const copilot = await openCopilot(page);
+  await copilot.getByLabel("描述要分析的问题").fill("我想加一个新的分析列。");
+  await copilot.getByRole("button", { name: "发送", exact: true }).click();
+
+  const preview = copilot.getByRole("region", { name: "列定义预览" });
+  await expect(preview).toContainText("缺失值和零分母如何处理？");
+  await expect(
+    preview.getByRole("button", { name: "确认并添加分析列" }),
+  ).toHaveCount(0);
+  await expect(
+    copilot.getByRole("button", { name: "退出列设计", exact: true }).first(),
+  ).toBeVisible();
+
+  await copilot
+    .getByLabel("描述要分析的问题")
+    .fill(
+      "列名收入成本差，用实际收入减成本，应用当前筛选的本期和基期，缺失显示不可用。",
+    );
+  await copilot.getByRole("button", { name: "发送", exact: true }).click();
+
+  await expect(preview).toContainText("收入成本差");
+  await expect(preview).toContainText("实际收入减成本");
+  await expect(preview).toContainText("计算表达式");
+  await expect(preview).toContainText("(实际收入 − 成本)");
+  await expect(preview).toContainText("适用范围");
+  await expect(preview).toContainText("缺失/零分母");
+  expect(requests).toHaveLength(2);
+  expect(requests[1].mode).toBe("column_design");
+  expect(requests[1].question).toBe(
+    "列名收入成本差，用实际收入减成本，应用当前筛选的本期和基期，缺失显示不可用。",
+  );
+  expect(requests[1].history).toEqual([
+    { role: "user", content: "我想加一个新的分析列。" },
+    {
+      role: "assistant",
+      content: expect.stringContaining("缺失值和零分母如何处理？"),
+    },
+  ]);
+
+  // 保存定义与查询不 mock：走真实后端并检查返回值和表格列头。
+  const savedResponse = page.waitForResponse(
+    (response) =>
+      response.url().includes("/formula-definitions") &&
+      response.request().method() === "POST",
+  );
+  const customQuery = page.waitForResponse(
+    (response) =>
+      response.url().includes("/query") &&
+      response.request().method() === "POST" &&
+      ((response.request().postDataJSON()?.custom_columns?.length as number) ||
+        0) > 0,
+  );
+  await preview
+    .getByRole("button", { name: "确认并添加分析列", exact: true })
+    .click();
+  const saved = await savedResponse;
+  expect(saved.ok()).toBeTruthy();
+  expect((await saved.json()).definition.name).toBe("收入成本差");
+  const query = await customQuery;
+  const customResult = await query.json();
+  // Decimal 以字符串保留精度（如 "1000.000000000000000000000000"），按数值断言。
+  expect(Number(customResult.summary.custom_0.current)).toBe(1000);
+  expect(Number(customResult.summary.custom_0.baseline)).toBe(6000);
+  expect(Number(customResult.summary.custom_0.delta)).toBe(-5000);
+  expect(Number(customResult.rows[0].values.custom_0.current)).toBe(1000);
+
+  await expect(
+    copilot.getByRole("status").filter({ hasText: "已添加分析列" }),
+  ).toBeVisible();
+  const header = page.locator(".ag-header-cell-text", {
+    hasText: "收入成本差",
+  });
+  // AG Grid 可能水平虚拟化列头；每次轮询滚到最右再检查是否已渲染。
+  await expect
+    .poll(
+      async () => {
+        for (const selector of [
+          ".ag-body-horizontal-scroll-viewport",
+          ".ag-center-cols-viewport",
+        ]) {
+          const scroller = page.locator(selector);
+          if (await scroller.count()) {
+            await scroller.evaluate((element) => {
+              const viewport = element as HTMLElement;
+              viewport.scrollLeft = viewport.scrollWidth;
+            });
+          }
+        }
+        return header.count();
+      },
+      { timeout: 20000 },
+    )
+    .toBeGreaterThan(0);
+  await expect(header).toBeVisible({ timeout: 20000 });
+});
diff --git a/tests/e2e/formula-export.spec.ts b/tests/e2e/formula-export.spec.ts
index 86a6885..235be0b 100644
--- a/tests/e2e/formula-export.spec.ts
+++ b/tests/e2e/formula-export.spec.ts
@@ -128,8 +128,9 @@ test("新增列：补充信息触发追问并重新确认后生成公式工作
   );
   await columns.getByRole("button", { name: "应用", exact: true }).click();
   const customResult = await (await customQuery).json();
-  expect(customResult.summary.custom_0.current).toBe("1000");
-  expect(customResult.rows[0].values.custom_0.current).toBe("1000");
+  // Decimal 以字符串保留存储精度（如 "1000.000000000000000000000000"），按数值断言。
+  expect(Number(customResult.summary.custom_0.current)).toBe(1000);
+  expect(Number(customResult.rows[0].values.custom_0.current)).toBe(1000);
 
   await page.getByRole("button", { name: "生成公式工作簿" }).click();
   const reopened = page.getByRole("dialog", { name: "生成公式工作簿" });