From 91c5d43c48af4e24685c8c86af40004fe90d1acc Mon Sep 17 00:00:00 2001
From: fengxiangdebaozi <10845145+fengxiangdebaozi@user.noreply.gitee.com>
Date: Thu, 23 Jul 2026 15:07:23 +0800
Subject: [PATCH] =?UTF-8?q?=E4=BB=A3=E7=A0=81=E6=8F=90=E4=BA=A4?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../workspace/messages/message-list-item.tsx  | 327 ++++++++++++------
 .../workspace/messages/message-list.tsx       |  67 ++--
 frontend-web/src/core/threads/hooks.ts        |  96 ++++-
 .../components/PositionBuiltinAgentChat.tsx   |  46 ++-
 .../components/PositionIntentInput.tsx        |  35 +-
 .../components/PositionNodeChat.tsx           | 108 +++++-
 .../pages/PositionRoundtablePage.tsx          | 104 ++++--
 .../hooks/useStep1Intent.ts                   |   8 +
 frontend-web/src/styles/globals.css           |  11 +-
 .../backend/app/gateway/routers/threads.py    | 164 +++++++++
 10 files changed, 808 insertions(+), 158 deletions(-)

diff --git a/frontend-web/src/components/workspace/messages/message-list-item.tsx b/frontend-web/src/components/workspace/messages/message-list-item.tsx
index 6ddf0f4a..33c07fff 100644
--- a/frontend-web/src/components/workspace/messages/message-list-item.tsx
+++ b/frontend-web/src/components/workspace/messages/message-list-item.tsx
@@ -135,11 +135,12 @@ export function MessageListItem({
   threadId,
   tokenUsageEnabled = false,
   displaySources = [],
-  extraRehypePlugins,
-  onEditResubmit,
-  onMessageDeleted,
-  turnTime,
-}: {
+  extraRehypePlugins,
+  onEditResubmit,
+  onEditSave,
+  onMessageDeleted,
+  turnTime,
+}: {
   className?: string;
   fitRowToContent?: boolean;
   /**
@@ -151,10 +152,11 @@ export function MessageListItem({
   isLoading?: boolean;
   threadId: string;
   tokenUsageEnabled?: boolean;
-  displaySources?: RuntimeDisplaySource[];
-  extraRehypePlugins?: ReturnType<typeof useRehypeSplitWordsIntoSpans>;
-  onEditResubmit?: (text: string) => void;
-  onMessageDeleted?: (deletedIds: string[]) => void;
+  displaySources?: RuntimeDisplaySource[];
+  extraRehypePlugins?: ReturnType<typeof useRehypeSplitWordsIntoSpans>;
+  onEditResubmit?: (text: string) => void;
+  onEditSave?: (messageId: string, text: string) => void | Promise<void>;
+  onMessageDeleted?: (deletedIds: string[]) => void;
   /**
    * Durable ask time of the turn this message belongs to (the preceding
    * question's `client_ts`). Used to time-stamp the AI answer, which carries no
@@ -162,14 +164,102 @@ export function MessageListItem({
    * wall clock at render time and appear to "drift" to now on every reload.
    */
   turnTime?: string;
-}) {
-  const isHuman = message.type === 'human';
-  const messageMarkdown =
-    extractContentFromMessage(message) ??
-    extractReasoningContentFromMessage(message) ??
-    '';
-  return (
-    <AIElementMessage
+}) {
+  const { t } = useI18n();
+  const isHuman = message.type === 'human';
+  const messageMarkdown =
+    extractContentFromMessage(message) ??
+    extractReasoningContentFromMessage(message) ??
+    '';
+  const [assistantEditing, setAssistantEditing] = useState(false);
+  const [assistantDraft, setAssistantDraft] = useState(messageMarkdown);
+  const [assistantSaving, setAssistantSaving] = useState(false);
+
+  useEffect(() => {
+    if (!assistantEditing) {
+      setAssistantDraft(messageMarkdown);
+    }
+  }, [assistantEditing, messageMarkdown]);
+
+  const canSaveAssistantEdit =
+    !isLoading &&
+    !isHuman &&
+    !!onEditSave &&
+    !!message.id &&
+    !message.id.startsWith('opt-') &&
+    !!messageMarkdown;
+  const confirmAssistantEdit = useCallback(async () => {
+    const value = assistantDraft.trim();
+    if (!value || !message.id || !onEditSave || assistantSaving) {
+      return;
+    }
+    setAssistantSaving(true);
+    try {
+      await onEditSave(message.id, value);
+      setAssistantEditing(false);
+    } catch {
+      // The page-level save callback owns user-facing error toasts. Keep the
+      // editor open so the user can adjust and retry.
+    } finally {
+      setAssistantSaving(false);
+    }
+  }, [assistantDraft, assistantSaving, message.id, onEditSave]);
+
+  if (!isHuman && assistantEditing) {
+    return (
+      <AIElementMessage
+        id={anchorId}
+        className={cn(
+          'group/conversation-message relative',
+          fitRowToContent ? 'max-w-full w-fit' : 'w-full',
+          anchorId && 'scroll-mt-20',
+          className,
+        )}
+        from="assistant"
+      >
+        <AIElementMessageContent className="w-full">
+          <div className="flex w-full flex-col gap-2 rounded-2xl border border-primary/20 bg-primary/5 p-3">
+            <Textarea
+              value={assistantDraft}
+              autoFocus
+              onChange={(event) => setAssistantDraft(event.currentTarget.value)}
+              onKeyDown={(event) => {
+                if (event.key === "Enter" && (event.metaKey || event.ctrlKey)) {
+                  event.preventDefault();
+                  void confirmAssistantEdit();
+                }
+                if (event.key === "Escape") {
+                  event.preventDefault();
+                  setAssistantEditing(false);
+                }
+              }}
+              className="min-h-32 resize-y text-[15px] leading-7"
+            />
+            <div className="flex items-center justify-end gap-2">
+              <Button
+                size="sm"
+                variant="ghost"
+                disabled={assistantSaving}
+                onClick={() => setAssistantEditing(false)}
+              >
+                {t.common.cancel}
+              </Button>
+              <Button
+                size="sm"
+                disabled={!assistantDraft.trim() || assistantSaving}
+                onClick={() => void confirmAssistantEdit()}
+              >
+                {assistantSaving ? "保存中..." : t.common.save}
+              </Button>
+            </div>
+          </div>
+        </AIElementMessageContent>
+      </AIElementMessage>
+    );
+  }
+
+  return (
+    <AIElementMessage
       id={anchorId}
       className={cn(
         'group/conversation-message relative',
@@ -187,11 +277,12 @@ export function MessageListItem({
         threadId={threadId}
         tokenUsageEnabled={tokenUsageEnabled}
         displaySources={displaySources}
-        extraRehypePlugins={extraRehypePlugins}
-        onEditResubmit={onEditResubmit}
-        onMessageDeleted={onMessageDeleted}
-        turnTime={turnTime}
-      />
+        extraRehypePlugins={extraRehypePlugins}
+        onEditResubmit={onEditResubmit}
+        onEditSave={isLoading ? undefined : onEditSave}
+        onMessageDeleted={onMessageDeleted}
+        turnTime={turnTime}
+      />
       {/*
         Human messages carry their own inline copy/edit toolbar inside
         MessageContent (above the timestamp). Only assistant answers use the
@@ -206,15 +297,28 @@ export function MessageListItem({
         >
           <div className="flex gap-1">
             <CopyButton clipboardData={messageMarkdown} />
-            {messageMarkdown && (
-              <DownloadWordButton
-                markdown={messageMarkdown}
-                fileName="message"
-              />
-            )}
-          </div>
-        </MessageToolbar>
-      )}
+            {messageMarkdown && (
+              <DownloadWordButton
+                markdown={messageMarkdown}
+                fileName="message"
+              />
+            )}
+            {canSaveAssistantEdit && (
+              <Tooltip content="编辑消息">
+                <Button
+                  size="icon-sm"
+                  type="button"
+                  variant="ghost"
+                  className="size-6"
+                  onClick={() => setAssistantEditing(true)}
+                >
+                  <PencilIcon size={11} />
+                </Button>
+              </Tooltip>
+            )}
+          </div>
+        </MessageToolbar>
+      )}
     </AIElementMessage>
   );
 }
@@ -228,26 +332,31 @@ export function MessageListItem({
  * the question; confirming sends the edited text as a brand-new turn (the
  * original question stays in the thread).
  */
-function HumanMessageBlock({
-  text,
-  pageContext,
-  filesList,
-  messageTime,
-  components,
-  onEditResubmit,
-  deleteButton,
-}: {
-  text: string;
-  pageContext?: EmbeddedPageContext | null;
-  filesList: React.ReactNode;
-  messageTime: { label: string; full: string } | null;
-  components: MarkdownContentProps["components"];
-  onEditResubmit?: (text: string) => void;
-  deleteButton?: React.ReactNode;
-}) {
-  const { t } = useI18n();
-  const [editing, setEditing] = useState(false);
-  const [draft, setDraft] = useState(text);
+function HumanMessageBlock({
+  messageId,
+  text,
+  pageContext,
+  filesList,
+  messageTime,
+  components,
+  onEditResubmit,
+  onEditSave,
+  deleteButton,
+}: {
+  messageId?: string;
+  text: string;
+  pageContext?: EmbeddedPageContext | null;
+  filesList: React.ReactNode;
+  messageTime: { label: string; full: string } | null;
+  components: MarkdownContentProps["components"];
+  onEditResubmit?: (text: string) => void;
+  onEditSave?: (messageId: string, text: string) => void | Promise<void>;
+  deleteButton?: React.ReactNode;
+}) {
+  const { t } = useI18n();
+  const [editing, setEditing] = useState(false);
+  const [draft, setDraft] = useState(text);
+  const [saving, setSaving] = useState(false);
 
   useEffect(() => {
     if (!editing) {
@@ -255,14 +364,27 @@ function HumanMessageBlock({
     }
   }, [text, editing]);
 
-  const confirmEdit = useCallback(() => {
-    const value = draft.trim();
-    if (!value) {
-      return;
-    }
-    onEditResubmit?.(value);
-    setEditing(false);
-  }, [draft, onEditResubmit]);
+  const confirmEdit = useCallback(async () => {
+    const value = draft.trim();
+    if (!value || saving) {
+      return;
+    }
+    if (onEditSave && messageId && !messageId.startsWith("opt-")) {
+      setSaving(true);
+      try {
+        await onEditSave(messageId, value);
+        setEditing(false);
+      } catch {
+        // The page-level save callback owns user-facing error toasts. Keep the
+        // editor open so the user can adjust and retry.
+      } finally {
+        setSaving(false);
+      }
+      return;
+    }
+    onEditResubmit?.(value);
+    setEditing(false);
+  }, [draft, messageId, onEditResubmit, onEditSave, saving]);
 
   if (editing) {
     return (
@@ -275,10 +397,10 @@ function HumanMessageBlock({
           onKeyDown={(event) => {
             if (event.key === "Enter" && (event.metaKey || event.ctrlKey)) {
               event.preventDefault();
-              confirmEdit();
-            }
-            if (event.key === "Escape") {
-              event.preventDefault();
+              void confirmEdit();
+            }
+            if (event.key === "Escape") {
+              event.preventDefault();
               setEditing(false);
             }
           }}
@@ -286,17 +408,22 @@ function HumanMessageBlock({
         />
         <div className="flex items-center justify-end gap-2">
           <Button
-            size="sm"
-            variant="ghost"
-            onClick={() => setEditing(false)}
-          >
-            {t.common.cancel}
-          </Button>
-          <Button size="sm" onClick={confirmEdit} disabled={!draft.trim()}>
-            {t.common.confirm}
-          </Button>
-        </div>
-      </div>
+            size="sm"
+            variant="ghost"
+            disabled={saving}
+            onClick={() => setEditing(false)}
+          >
+            {t.common.cancel}
+          </Button>
+          <Button
+            size="sm"
+            onClick={() => void confirmEdit()}
+            disabled={!draft.trim() || saving}
+          >
+            {saving ? "保存中..." : onEditSave ? t.common.save : t.common.confirm}
+          </Button>
+        </div>
+      </div>
     );
   }
 
@@ -324,11 +451,11 @@ function HumanMessageBlock({
       {(text || deleteButton) && (
         <div className="flex items-center gap-0.5 opacity-0 transition-opacity duration-200 group-hover/conversation-message:opacity-100">
           {text && <CopyButton clipboardData={text} className="size-6" />}
-          {text && onEditResubmit && (
-            <Tooltip content={t.inputBox.editQuestion}>
-              <Button
-                size="icon-sm"
-                type="button"
+          {text && (onEditResubmit || onEditSave) && (
+            <Tooltip content={onEditSave ? "编辑消息" : t.inputBox.editQuestion}>
+              <Button
+                size="icon-sm"
+                type="button"
                 variant="ghost"
                 className="size-6"
                 onClick={() => setEditing(true)}
@@ -396,22 +523,24 @@ function MessageContent_({
   threadId,
   tokenUsageEnabled = false,
   displaySources = [],
-  extraRehypePlugins,
-  onEditResubmit,
-  onMessageDeleted,
-  turnTime,
-}: {
+  extraRehypePlugins,
+  onEditResubmit,
+  onEditSave,
+  onMessageDeleted,
+  turnTime,
+}: {
   className?: string;
   message: Message;
   isLoading?: boolean;
   threadId: string;
   tokenUsageEnabled?: boolean;
-  displaySources?: RuntimeDisplaySource[];
-  extraRehypePlugins?: ReturnType<typeof useRehypeSplitWordsIntoSpans>;
-  onEditResubmit?: (text: string) => void;
-  onMessageDeleted?: (deletedIds: string[]) => void;
-  turnTime?: string;
-}) {
+  displaySources?: RuntimeDisplaySource[];
+  extraRehypePlugins?: ReturnType<typeof useRehypeSplitWordsIntoSpans>;
+  onEditResubmit?: (text: string) => void;
+  onEditSave?: (messageId: string, text: string) => void | Promise<void>;
+  onMessageDeleted?: (deletedIds: string[]) => void;
+  turnTime?: string;
+}) {
   const baseRehypePlugins = useRehypeSplitWordsIntoSpans(isLoading);
 
   // Streamdown splits content into per-block processors; calling the factory
@@ -555,14 +684,16 @@ function MessageContent_({
     const canDelete =
       !!onMessageDeleted && !!message.id && !message.id.startsWith('opt-');
     return (
-      <HumanMessageBlock
-        text={parsedHumanContent.content}
-        pageContext={parsedHumanContent.pageContext}
-        filesList={filesList}
-        messageTime={messageTime}
-        components={components}
-        onEditResubmit={onEditResubmit}
-        deleteButton={
+      <HumanMessageBlock
+        messageId={message.id}
+        text={parsedHumanContent.content}
+        pageContext={parsedHumanContent.pageContext}
+        filesList={filesList}
+        messageTime={messageTime}
+        components={components}
+        onEditResubmit={onEditResubmit}
+        onEditSave={onEditSave}
+        deleteButton={
           canDelete ? (
             <DeleteMessageButton
               threadId={threadId}
diff --git a/frontend-web/src/components/workspace/messages/message-list.tsx b/frontend-web/src/components/workspace/messages/message-list.tsx
index a117d4fa..07e33688 100644
--- a/frontend-web/src/components/workspace/messages/message-list.tsx
+++ b/frontend-web/src/components/workspace/messages/message-list.tsx
@@ -97,10 +97,13 @@ export function MessageList({
   tokenUsageEnabled = false,
   extraRehypePlugins,
   scrollButtonClassName,
-  onClarificationSubmit,
-  onEditResubmit,
-  onSetupAgentApprove,
-  onSetupAgentReject,
+  onClarificationSubmit,
+  onEditResubmit,
+  onEditSave,
+  messageContentOverrides,
+  externallyHiddenMessageIds,
+  onSetupAgentApprove,
+  onSetupAgentReject,
   onSetupWritingApprove,
   onSetupWritingReject,
   onSetupWritingStart,
@@ -116,9 +119,12 @@ export function MessageList({
   /** 额外定位「回到最新」悬浮按钮——不同页面输入框高度不同，需上移让位。 */
   scrollButtonClassName?: string;
   extraRehypePlugins?: ReturnType<typeof useRehypeSplitWordsIntoSpans>;
-  onClarificationSubmit?: (answer: string) => void | Promise<void>;
-  onEditResubmit?: (text: string) => void;
-  onSetupAgentApprove?: (payload: SetupAgentApprovalPayload) => void | Promise<void>;
+  onClarificationSubmit?: (answer: string) => void | Promise<void>;
+  onEditResubmit?: (text: string) => void;
+  onEditSave?: (messageId: string, text: string) => void | Promise<void>;
+  messageContentOverrides?: Record<string, string>;
+  externallyHiddenMessageIds?: Set<string>;
+  onSetupAgentApprove?: (payload: SetupAgentApprovalPayload) => void | Promise<void>;
   onSetupAgentReject?: (payload: SetupAgentApprovalPayload) => void | Promise<void>;
   onSetupWritingApprove?: (payload: SetupWritingApprovalPayload) => void | Promise<void>;
   onSetupWritingReject?: (payload: SetupWritingApprovalPayload) => void | Promise<void>;
@@ -157,17 +163,33 @@ export function MessageList({
     });
   }, []);
 
-  const allMessages = useMemo(
-    () => thread.messages.filter((m) => !isHiddenFromUIMessage(m)),
-    [thread.messages],
-  );
-  const messages = useMemo(
-    () =>
-      hiddenMessageIds.size === 0
-        ? allMessages
-        : allMessages.filter((m) => !m.id || !hiddenMessageIds.has(m.id)),
-    [allMessages, hiddenMessageIds],
-  );
+  const allMessages = useMemo(() => {
+    const hasOverrides = messageContentOverrides && Object.keys(messageContentOverrides).length > 0;
+    return thread.messages
+      .filter((m) => !isHiddenFromUIMessage(m))
+      .map((message) => {
+        const override =
+          hasOverrides && message.id
+            ? messageContentOverrides?.[message.id]
+            : undefined;
+        return override === undefined
+          ? message
+          : ({ ...message, content: override } as Message);
+      });
+  }, [messageContentOverrides, thread.messages]);
+  const messages = useMemo(
+    () => {
+      const externalHidden = externallyHiddenMessageIds ?? new Set<string>();
+      return hiddenMessageIds.size === 0 && externalHidden.size === 0
+        ? allMessages
+        : allMessages.filter(
+            (m) =>
+              !m.id ||
+              (!hiddenMessageIds.has(m.id) && !externalHidden.has(m.id)),
+          );
+    },
+    [allMessages, externallyHiddenMessageIds, hiddenMessageIds],
+  );
 
   const askTimes = useChatAskTimes();
 
@@ -382,10 +404,11 @@ export function MessageList({
                   threadId={threadId}
                   tokenUsageEnabled={tokenUsageEnabled}
                   displaySources={displaySources}
-                  extraRehypePlugins={extraRehypePlugins}
-                  onEditResubmit={onEditResubmit}
-                  onMessageDeleted={
-                    allowDelete ? handleMessageDeleted : undefined
+                  extraRehypePlugins={extraRehypePlugins}
+                  onEditResubmit={onEditResubmit}
+                  onEditSave={onEditSave}
+                  onMessageDeleted={
+                    allowDelete ? handleMessageDeleted : undefined
                   }
                   turnTime={msg.id ? turnTimes.get(msg.id) : undefined}
                 />
diff --git a/frontend-web/src/core/threads/hooks.ts b/frontend-web/src/core/threads/hooks.ts
index e744ced7..4b61756f 100644
--- a/frontend-web/src/core/threads/hooks.ts
+++ b/frontend-web/src/core/threads/hooks.ts
@@ -1363,8 +1363,8 @@ export function useDeleteThread() {
  * `MessageList`) so the removal shows immediately; a reload then reads the
  * persisted, already-trimmed state.
  */
-export function useDeleteMessage() {
-  return useMutation({
+export function useDeleteMessage() {
+  return useMutation({
     mutationFn: async ({
       threadId,
       messageId,
@@ -1394,12 +1394,92 @@ export function useDeleteMessage() {
       // Fall back to the requested id so the caller can always hide something.
       return body.deleted_ids?.length ? body.deleted_ids : [messageId];
     },
-  });
-}
-
-/**
- * Merge metadata into a conversation's record via the Gateway
- * `PATCH /api/threads/{id}` route. Used to persist per-conversation flags such
+  });
+}
+
+/**
+ * Clear all messages from a thread checkpoint. The caller should immediately
+ * hide the returned ids locally because the active stream cache may still hold
+ * the old message objects until a reload/refetch reads the trimmed checkpoint.
+ */
+export function useClearThreadMessages() {
+  return useMutation({
+    mutationFn: async ({
+      threadId,
+    }: {
+      threadId: string;
+    }): Promise<string[]> => {
+      const response = await apiFetch(
+        `${getBackendBaseURL()}/api/threads/${encodeURIComponent(
+          threadId,
+        )}/messages`,
+        {
+          method: "DELETE",
+        },
+      );
+
+      if (!response.ok) {
+        const error = await response
+          .json()
+          .catch(() => ({ detail: "清空对话失败。" }));
+        throw new Error(error.detail ?? "清空对话失败。");
+      }
+
+      const body = (await response.json().catch(() => ({}))) as {
+        deleted_ids?: string[];
+      };
+      return body.deleted_ids ?? [];
+    },
+  });
+}
+
+/**
+ * Persist an in-place message edit in the latest thread checkpoint.
+ *
+ * This is opt-in UI behaviour: most chat pages keep their existing
+ * "edit question and resubmit" affordance, while position roundtable can pass
+ * this mutation down to save the original message content itself.
+ */
+export function useEditMessage() {
+  return useMutation({
+    mutationFn: async ({
+      threadId,
+      messageId,
+      content,
+    }: {
+      threadId: string;
+      messageId: string;
+      content: string;
+    }): Promise<Message> => {
+      const response = await apiFetch(
+        `${getBackendBaseURL()}/api/threads/${encodeURIComponent(
+          threadId,
+        )}/messages/${encodeURIComponent(messageId)}`,
+        {
+          method: "PATCH",
+          headers: { "Content-Type": "application/json" },
+          body: JSON.stringify({ content }),
+        },
+      );
+
+      if (!response.ok) {
+        const error = await response
+          .json()
+          .catch(() => ({ detail: "消息保存失败。" }));
+        throw new Error(error.detail ?? "消息保存失败。");
+      }
+
+      const body = (await response.json().catch(() => ({}))) as {
+        message?: Message;
+      };
+      return body.message ?? ({ id: messageId, type: "human", content } as Message);
+    },
+  });
+}
+
+/**
+ * Merge metadata into a conversation's record via the Gateway
+ * `PATCH /api/threads/{id}` route. Used to persist per-conversation flags such
  * as `is_pinned` (置顶) and `is_favorite` (收藏) — a conversation belongs to a
  * single user, so these live directly on the thread metadata (no join table).
  * Updates the `["threads", "search"]` cache optimistically so the UI reflects
diff --git a/frontend-web/src/position-roundtable/components/PositionBuiltinAgentChat.tsx b/frontend-web/src/position-roundtable/components/PositionBuiltinAgentChat.tsx
index b95285e2..a1f20a52 100644
--- a/frontend-web/src/position-roundtable/components/PositionBuiltinAgentChat.tsx
+++ b/frontend-web/src/position-roundtable/components/PositionBuiltinAgentChat.tsx
@@ -1,14 +1,15 @@
 import type { BaseStream } from "@langchain/langgraph-sdk/react";
 import { useCallback, useEffect, useMemo, useRef, useState } from "react";
-import { Bot, CheckCircle2, FileText, LockKeyhole, Sparkles, Target } from "lucide-react";
+import { Bot, CheckCircle2, FileText, LockKeyhole, Sparkles, Target, Trash2 } from "lucide-react";
 import { toast } from "sonner";
+import { Button as TButton } from "tdesign-react";
 
 import type { PromptInputMessage } from "@/components/ai-elements/prompt-input";
 import { MessageList } from "@/components/workspace/messages";
 import { ThreadContext } from "@/components/workspace/messages/context";
 import { useAgent } from "@/core/agents";
 import { useLocalSettings } from "@/core/settings";
-import { useThreadStream } from "@/core/threads/hooks";
+import { useClearThreadMessages, useThreadStream } from "@/core/threads/hooks";
 import type { AgentThreadState } from "@/core/threads/types";
 import { textOfMessage } from "@/core/threads/utils";
 import { uuid } from "@/core/utils/uuid";
@@ -234,6 +235,10 @@ export function PositionBuiltinAgentChat({
     useState<PendingBuiltinSubmission | null>(null);
   const pendingSubmissionRef = useRef(false);
   const handledAutoStartRequestRef = useRef<number | undefined>(undefined);
+  const clearThreadMessages = useClearThreadMessages();
+  const [externallyHiddenMessageIds, setExternallyHiddenMessageIds] = useState<Set<string>>(
+    () => new Set(),
+  );
 
   useEffect(() => {
     setAssistantId(fallbackAgentId);
@@ -244,6 +249,7 @@ export function PositionBuiltinAgentChat({
     pendingSubmissionRef.current = false;
     setPendingSubmission(null);
     handledAutoStartRequestRef.current = undefined;
+    setExternallyHiddenMessageIds(new Set());
   }, [fallbackAgentId, kind, persistedThreadId, session?.id]);
 
   const canWrite =
@@ -479,6 +485,31 @@ export function PositionBuiltinAgentChat({
     [activeThreadId, onPreviewArtifact],
   );
 
+  const handleClearConversation = useCallback(async () => {
+    const threadId = boundThreadIdRef.current;
+    if (!threadId) {
+      toast.info("当前智能体还没有可清空的对话");
+      return;
+    }
+    if (thread.isLoading || isSubmitting) {
+      toast.info("智能体正在生成，完成后再清空对话");
+      return;
+    }
+    const confirmed = window.confirm("确定清空当前智能体对话吗？清空后不可恢复。");
+    if (!confirmed) return;
+
+    const fallbackIds = thread.messages
+      .map((message) => message.id)
+      .filter((id): id is string => Boolean(id));
+    try {
+      const deletedIds = await clearThreadMessages.mutateAsync({ threadId });
+      setExternallyHiddenMessageIds(new Set(deletedIds.length ? deletedIds : fallbackIds));
+      toast.success("对话已清空");
+    } catch (error) {
+      toast.error(error instanceof Error ? error.message : "清空对话失败");
+    }
+  }, [clearThreadMessages, isSubmitting, thread.isLoading, thread.messages]);
+
   useEffect(() => {
     if (
       !autoStartRequestKey ||
@@ -534,6 +565,16 @@ export function PositionBuiltinAgentChat({
               onSelect={onSelectBuiltinAgent}
             />
           )}
+          <TButton
+            size="small"
+            variant="outline"
+            shape="circle"
+            className="!h-8 !w-8 !min-w-8 !shrink-0 !p-0 !bg-white/90 dark:!border-[#2b8ffe]/55 dark:!bg-[#082d5f]/90"
+            icon={<Trash2 className="!size-4 !shrink-0" />}
+            disabled={!boundThreadId || thread.isLoading || isSubmitting || clearThreadMessages.isPending}
+            onClick={() => void handleClearConversation()}
+            title="清空当前智能体对话"
+          />
         </header>
 
         {persistedArtifacts.length > 0 && (
@@ -580,6 +621,7 @@ export function PositionBuiltinAgentChat({
             scrollButtonClassName="bottom-6"
             onEditResubmit={(text) => void handleSubmit({ text, files: [] })}
             onOpenArtifact={handleOpenMessageArtifact}
+            externallyHiddenMessageIds={externallyHiddenMessageIds}
           />
         ) : (
           <div className="flex min-h-0 flex-1 flex-col items-center justify-center px-8 text-center">
diff --git a/frontend-web/src/position-roundtable/components/PositionIntentInput.tsx b/frontend-web/src/position-roundtable/components/PositionIntentInput.tsx
index 7e228ff4..6b51568d 100644
--- a/frontend-web/src/position-roundtable/components/PositionIntentInput.tsx
+++ b/frontend-web/src/position-roundtable/components/PositionIntentInput.tsx
@@ -11,10 +11,22 @@ import {
   Sparkles,
   X,
 } from "lucide-react";
+import { Select as TSelect } from "tdesign-react";
 
 import { AutoGrowTextarea } from "@/components/ui/auto-grow-textarea";
 import type { Step1InputAreaProps } from "@/roundtable-planning/components/Step1Panel";
 
+interface PositionIntentModelOption {
+  label: string;
+  value: string;
+}
+
+interface PositionIntentInputProps extends Step1InputAreaProps {
+  modelOptions?: PositionIntentModelOption[];
+  selectedModel?: string;
+  onSelectedModelChange?: (model: string) => void;
+}
+
 /** Keep attachment metadata presentation local to this position-only composer. */
 function formatFileSize(bytes: number): string {
   if (bytes < 1024) return `${bytes} B`;
@@ -49,7 +61,10 @@ export function PositionIntentInput({
   hideEnterRoundtable,
   onManualSave,
   onTriggerToast,
-}: Step1InputAreaProps) {
+  modelOptions = [],
+  selectedModel,
+  onSelectedModelChange,
+}: PositionIntentInputProps) {
   // Files are owned by Step1Panel. This ref only opens the native picker and
   // forwards its selection through onAddFiles, so replacement layouts do not
   // accidentally create a second attachment state.
@@ -162,6 +177,24 @@ export function PositionIntentInput({
             </button>
           </div>
           <div className="ml-auto flex min-w-0 flex-wrap items-center justify-end gap-1.5">
+          {modelOptions.length > 0 && (
+            <div
+              className="flex h-10 shrink-0 items-center gap-1.5 rounded-[4px] border border-slate-200 bg-white pl-2 text-xs font-bold text-slate-700 shadow-sm dark:border-[#2b8ffe]/35 dark:bg-[#102f63] dark:text-[#b9d3f7]"
+              title="切换意图理解模型"
+            >
+              <Sparkles className="size-3.5 shrink-0 text-primary dark:text-[#73c8ff]" />
+              <TSelect
+                size="small"
+                aria-label="切换意图理解模型"
+                value={selectedModel}
+                options={modelOptions}
+                disabled={isSending}
+                onChange={(value) => onSelectedModelChange?.(String(value))}
+                className="w-[150px] shrink-0 [&_.t-input]:!h-8 [&_.t-input]:!border-0 [&_.t-input]:!bg-transparent [&_.t-input]:!px-1 [&_.t-input]:!text-xs [&_.t-input]:!font-bold [&_.t-input]:!shadow-none dark:[&_.t-input]:!text-[#dceaff]"
+                popupProps={{ overlayClassName: "z-[80]" }}
+              />
+            </div>
+          )}
           <button
             id="send-message-btn"
             type="button"
diff --git a/frontend-web/src/position-roundtable/components/PositionNodeChat.tsx b/frontend-web/src/position-roundtable/components/PositionNodeChat.tsx
index fe39f266..0337da22 100644
--- a/frontend-web/src/position-roundtable/components/PositionNodeChat.tsx
+++ b/frontend-web/src/position-roundtable/components/PositionNodeChat.tsx
@@ -1,6 +1,6 @@
 import type { BaseStream } from "@langchain/langgraph-sdk/react";
 import { useCallback, useEffect, useMemo, useRef, useState } from "react";
-import { Bot, FileText, LockKeyhole, Settings } from "lucide-react";
+import { Bot, FileText, LockKeyhole, Settings, Trash2 } from "lucide-react";
 import { toast } from "sonner";
 import { Button as TButton, Select as TSelect } from "tdesign-react";
 import type { PromptInputMessage } from "@/components/ai-elements/prompt-input";
@@ -8,7 +8,7 @@ import { ThreadContext } from "@/components/workspace/messages/context";
 import { MessageList } from "@/components/workspace/messages";
 import { useAgent } from "@/core/agents";
 import { useLocalSettings } from "@/core/settings";
-import { useThreadStream } from "@/core/threads/hooks";
+import { useClearThreadMessages, useEditMessage, useThreadStream } from "@/core/threads/hooks";
 import type { AgentThreadState } from "@/core/threads/types";
 import { textOfMessage } from "@/core/threads/utils";
 import { uuid } from "@/core/utils/uuid";
@@ -221,6 +221,12 @@ export function PositionNodeChat({
   const draftThreadIdRef = useRef(node.threadId ?? uuid());
   const upstreamRevisionRef = useRef<Record<string, unknown> | null>(null);
   const autoPreviewedArtifactKeyRef = useRef<string | null>(null);
+  const clearThreadMessages = useClearThreadMessages();
+  const editMessage = useEditMessage();
+  const [messageContentOverrides, setMessageContentOverrides] = useState<Record<string, string>>({});
+  const [externallyHiddenMessageIds, setExternallyHiddenMessageIds] = useState<Set<string>>(
+    () => new Set(),
+  );
   const nodeArtifacts = useMemo(() => readNodeArtifacts(node.artifactManifest), [node.artifactManifest]);
   const canWrite =
     sessionStatus !== "archived" &&
@@ -232,7 +238,9 @@ export function PositionNodeChat({
   useEffect(() => {
     setBoundThreadId(node.threadId);
     boundThreadIdRef.current = node.threadId;
-  }, [node.threadId]);
+    setMessageContentOverrides({});
+    setExternallyHiddenMessageIds(new Set());
+  }, [node.nodeKey, node.threadId]);
 
   const bindCreatedThread = useCallback(
     (threadId: string) => {
@@ -313,6 +321,15 @@ export function PositionNodeChat({
 
   const activeThreadId =
     boundThreadIdRef.current ?? actualThreadId ?? boundThreadId ?? draftThreadIdRef.current;
+  const latestAiMessageId = useMemo(() => {
+    for (let index = thread.messages.length - 1; index >= 0; index -= 1) {
+      const message = thread.messages[index];
+      if (message?.type === "ai" && message.id && (textOfMessage(message) ?? "").trim()) {
+        return message.id;
+      }
+    }
+    return null;
+  }, [thread.messages]);
   const handleOpenMessageArtifact = useCallback(
     (filepath: string) => {
       onPreviewArtifact?.({
@@ -324,6 +341,78 @@ export function PositionNodeChat({
     },
     [activeThreadId, onPreviewArtifact],
   );
+  const handleSaveMessageEdit = useCallback(
+    async (messageId: string, text: string) => {
+      const threadId = boundThreadIdRef.current;
+      const content = text.trim();
+      if (!threadId || !content) return;
+      try {
+        const updatedMessage = await editMessage.mutateAsync({
+          threadId,
+          messageId,
+          content,
+        });
+        setMessageContentOverrides((prev) => ({
+          ...prev,
+          [messageId]: textOfMessage(updatedMessage) ?? content,
+        }));
+        if (updatedMessage.type === "ai" && messageId === latestAiMessageId) {
+          try {
+            const updatedNode = await completePositionNodeTurn(sessionId, node.nodeKey, {
+              latestAnswer: content,
+              artifactManifest: node.artifactManifest,
+              upstreamRevision: node.upstreamRevision,
+            });
+            onNodeUpdate(updatedNode);
+          } catch (syncError) {
+            toast.warning(
+              `消息已保存，但节点交接摘要同步失败：${
+                syncError instanceof Error ? syncError.message : String(syncError)
+              }`,
+            );
+          }
+        }
+        toast.success("消息已保存");
+      } catch (error) {
+        toast.error(error instanceof Error ? error.message : "消息保存失败");
+        throw error;
+      }
+    },
+    [
+      editMessage,
+      latestAiMessageId,
+      node.artifactManifest,
+      node.nodeKey,
+      node.upstreamRevision,
+      onNodeUpdate,
+      sessionId,
+    ],
+  );
+  const handleClearConversation = useCallback(async () => {
+    const threadId = boundThreadIdRef.current;
+    if (!threadId) {
+      toast.info("当前智能体还没有可清空的对话");
+      return;
+    }
+    if (thread.isLoading) {
+      toast.info("智能体正在生成，完成后再清空对话");
+      return;
+    }
+    const confirmed = window.confirm("确定清空当前智能体对话吗？清空后不可恢复。");
+    if (!confirmed) return;
+
+    const fallbackIds = thread.messages
+      .map((message) => message.id)
+      .filter((id): id is string => Boolean(id));
+    try {
+      const deletedIds = await clearThreadMessages.mutateAsync({ threadId });
+      setExternallyHiddenMessageIds(new Set(deletedIds.length ? deletedIds : fallbackIds));
+      setMessageContentOverrides({});
+      toast.success("对话已清空");
+    } catch (error) {
+      toast.error(error instanceof Error ? error.message : "清空对话失败");
+    }
+  }, [clearThreadMessages, thread.isLoading, thread.messages]);
   const hasMultipleSwitchOptions = switchOptions.length > 1;
   const switchSelectOptions = useMemo(
     () =>
@@ -504,6 +593,16 @@ export function PositionNodeChat({
               onSelect={onSelectBuiltinAgent}
             />
           )}
+          <TButton
+            size="small"
+            variant="outline"
+            shape="circle"
+            className="!h-8 !w-8 !min-w-8 !shrink-0 !p-0 !bg-white/90 dark:!border-[#2b8ffe]/55 dark:!bg-[#082d5f]/90"
+            icon={<Trash2 className="!size-4 !shrink-0" />}
+            disabled={!boundThreadId || thread.isLoading || clearThreadMessages.isPending}
+            onClick={() => void handleClearConversation()}
+            title="清空当前智能体对话"
+          />
           {onOpenConfiguration && (
             <TButton
               size="small"
@@ -560,6 +659,9 @@ export function PositionNodeChat({
             paddingBottom={24}
             scrollButtonClassName="bottom-6"
             onEditResubmit={(text) => void handleSubmit({ text, files: [] })}
+            onEditSave={handleSaveMessageEdit}
+            messageContentOverrides={messageContentOverrides}
+            externallyHiddenMessageIds={externallyHiddenMessageIds}
             onOpenArtifact={handleOpenMessageArtifact}
           />
         ) : (
diff --git a/frontend-web/src/position-roundtable/pages/PositionRoundtablePage.tsx b/frontend-web/src/position-roundtable/pages/PositionRoundtablePage.tsx
index 87b6d8b4..8c2b6dca 100644
--- a/frontend-web/src/position-roundtable/pages/PositionRoundtablePage.tsx
+++ b/frontend-web/src/position-roundtable/pages/PositionRoundtablePage.tsx
@@ -26,6 +26,7 @@ import {
   Settings,
   Sparkles,
   Target,
+  Trash2,
   UserRoundCog,
   XCircle,
   type LucideIcon,
@@ -66,6 +67,7 @@ import { useAgent } from "@/core/agents";
 import { loadArtifactContent } from "@/core/artifacts/loader";
 import type { Agent } from "@/core/agents";
 import { useModels } from "@/core/models/hooks";
+import { useClearThreadMessages } from "@/core/threads/hooks";
 import type { AgentThreadState } from "@/core/threads/types";
 import { textOfMessage } from "@/core/threads/utils";
 import { desensitize } from "@/lib/desensitize";
@@ -616,7 +618,23 @@ export default function PositionRoundtablePage({
   );
 
   const { models } = useModels();
-  const selectedModel = models[0]?.name ?? "";
+  const [selectedModel, setSelectedModel] = useState("");
+  useEffect(() => {
+    if (models.length === 0) return;
+    const stillExists = models.some((model) => model.name === selectedModel);
+    if (!selectedModel || !stillExists) {
+      setSelectedModel(models[0]?.name ?? "");
+    }
+  }, [models, selectedModel]);
+  const intentModelOptions = useMemo(
+    () =>
+      models.map((model) => ({
+        label: model.display_name || model.name,
+        value: model.name,
+      })),
+    [models],
+  );
+  const clearIntentThreadMessages = useClearThreadMessages();
   const triggerToast = useCallback((message: string) => toast.info(message), []);
   const intent = useStep1Intent({
     // 全岗位共用原会商的对话接口与输入面板；岗位运行编排后续再按角色接入。
@@ -633,6 +651,26 @@ export default function PositionRoundtablePage({
   const persistedIntentRef = useRef<string | null>(null);
   const isArchivedSession = positionSession?.status === "archived";
 
+  const handleClearIntentConversation = useCallback(async () => {
+    if (intent.isIntentSending) {
+      toast.info("意图理解正在生成，完成后再清空对话");
+      return;
+    }
+    const confirmed = window.confirm("确定清空意图理解对话吗？清空后不可恢复。");
+    if (!confirmed) return;
+    try {
+      if (intent.intentThreadId) {
+        await clearIntentThreadMessages.mutateAsync({
+          threadId: intent.intentThreadId,
+        });
+      }
+      intent.clearInteractiveMessages();
+      toast.success("意图理解对话已清空");
+    } catch (error) {
+      toast.error(error instanceof Error ? error.message : "清空意图理解对话失败");
+    }
+  }, [clearIntentThreadMessages, intent]);
+
   const syncSessionUrl = useCallback(
     (sessionId: string, nextTaskId: string) => {
       const next = new URLSearchParams(searchParamsString);
@@ -1491,6 +1529,18 @@ export default function PositionRoundtablePage({
             </div>
           </div>
         }
+        headerRightSlot={
+          <TButton
+            size="small"
+            variant="outline"
+            shape="circle"
+            className="!h-8 !w-8 !min-w-8 !shrink-0 !p-0 !bg-white/90 dark:!border-[#2b8ffe]/55 dark:!bg-[#082d5f]/90"
+            icon={<Trash2 className="!size-4 !shrink-0" />}
+            disabled={intent.isIntentSending || clearIntentThreadMessages.isPending}
+            onClick={() => void handleClearIntentConversation()}
+            title="清空意图理解对话"
+          />
+        }
         interactiveMessages={intent.interactiveMessages}
         intentThreadId={intent.intentThreadId}
         intentReady={chainStarted ? frozenIntent ?? intent.intentReady : intent.intentReady}
@@ -1538,7 +1588,14 @@ export default function PositionRoundtablePage({
             </button>
           ) : undefined
         }
-        inputArea={(inputProps) => <PositionIntentInput {...inputProps} />}
+        inputArea={(inputProps) => (
+          <PositionIntentInput
+            {...inputProps}
+            modelOptions={intentModelOptions}
+            selectedModel={selectedModel}
+            onSelectedModelChange={setSelectedModel}
+          />
+        )}
         onManualSave={() => undefined}
         onTriggerToast={triggerToast}
         submitIntentClarifications={intent.submitIntentClarifications}
@@ -1747,7 +1804,7 @@ export default function PositionRoundtablePage({
             onClick={() => {
               setLeftPanelCollapsed(false);
             }}
-            className="absolute left-3 top-3 z-20 flex h-10 w-[30px] items-center justify-center rounded-r-[4px] border border-l-0 border-[#2b8ffe]/60 bg-[#032650]/95 shadow-[4px_0_12px_rgba(0,0,0,0.18)] transition-colors hover:bg-[#0b386d] focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-[#45c3f3]/70"
+            className="absolute left-3 top-3 z-20 flex h-10 w-[30px] items-center justify-center rounded-r-[4px] border border-l-0 border-primary/25 bg-white/95 text-primary shadow-[4px_0_12px_rgba(15,23,42,0.08)] transition-colors hover:bg-primary/5 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-primary/25 dark:border-[#2b8ffe]/60 dark:bg-[#032650]/95 dark:shadow-[4px_0_12px_rgba(0,0,0,0.18)] dark:hover:bg-[#0b386d] dark:focus-visible:ring-[#45c3f3]/70"
           >
             <img src={expandLogo} alt="" className="size-4" />
           </button>
@@ -1892,6 +1949,7 @@ export default function PositionRoundtablePage({
                 filepath={sandboxArtifact.path}
                 threadId={sandboxArtifact.threadId}
                 onClose={closeSandbox}
+                allowVirtualMarkdownEdit
                 disableDesensitize
                 hideFileName
               />
@@ -2795,7 +2853,7 @@ function HoverEditButton({
       aria-label={title}
       onClick={onClick}
       className={cn(
-        "pointer-events-none flex size-7 shrink-0 items-center justify-center rounded-[4px] text-[#45c3f3] opacity-0 transition-[opacity,color,background-color] duration-150 hover:bg-[#45c3f3]/10 hover:text-[#a2e1f9] focus-visible:pointer-events-auto focus-visible:opacity-100 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-[#45c3f3]/65 motion-reduce:transition-none",
+        "pointer-events-none flex size-7 shrink-0 items-center justify-center rounded-[4px] text-primary opacity-0 transition-[opacity,color,background-color] duration-150 hover:bg-primary/10 hover:text-primary focus-visible:pointer-events-auto focus-visible:opacity-100 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-primary/25 motion-reduce:transition-none dark:text-[#45c3f3] dark:hover:bg-[#45c3f3]/10 dark:hover:text-[#a2e1f9] dark:focus-visible:ring-[#45c3f3]/65",
         revealClassName,
       )}
     >
@@ -2834,19 +2892,19 @@ function TaskAnalysisPanel({
         className,
       )}
     >
-      <div className="relative flex h-10 items-center border-b border-slate-200 !bg-[linear-gradient(89.65deg,#0062d9_0.03%,#0062d900_99.97%)] px-4 dark:border-b-[#2b8ffe]/60 dark:after:absolute dark:after:inset-x-0 dark:after:bottom-[-1px] dark:after:h-px dark:after:bg-[#45c3f3]/85 dark:after:content-['']">
+      <div className="relative flex h-10 items-center border-b border-rose-100 bg-[linear-gradient(89.65deg,rgba(245,34,45,0.10)_0.03%,rgba(245,34,45,0)_99.97%)] px-4 dark:!bg-[linear-gradient(89.65deg,#0062d9_0.03%,#0062d900_99.97%)] dark:border-b-[#2b8ffe]/60 dark:after:absolute dark:after:inset-x-0 dark:after:bottom-[-1px] dark:after:h-px dark:after:bg-[#45c3f3]/85 dark:after:content-['']">
         <span
           aria-hidden="true"
-          className="mr-3 h-5 w-1 shrink-0 rounded-l-[2px] rounded-br-[2px] bg-[linear-gradient(167.47deg,#a2e1f9_0%,#45c3f3_100%)]"
+          className="mr-3 h-5 w-1 shrink-0 rounded-l-[2px] rounded-br-[2px] bg-[linear-gradient(167.47deg,#f15959_0%,#cc1925_100%)] dark:bg-[linear-gradient(167.47deg,#a2e1f9_0%,#45c3f3_100%)]"
         />
-        <h2 className="text-base font-[550] tracking-wide text-white">任务分析</h2>
+        <h2 className="text-base font-[550] tracking-wide text-slate-900 dark:text-white">任务分析</h2>
         <button
           type="button"
           title={collapsed ? "展开任务分析" : "收起任务分析"}
           aria-label={collapsed ? "展开任务分析" : "收起任务分析"}
           aria-expanded={!collapsed}
           onClick={() => onCollapsedChange(!collapsed)}
-          className="relative z-10 ml-auto flex size-7 shrink-0 items-center justify-center rounded-[4px] transition-colors hover:bg-[#45c3f3]/10 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-[#45c3f3]/65"
+          className="relative z-10 ml-auto flex size-7 shrink-0 items-center justify-center rounded-[4px] transition-colors hover:bg-primary/10 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-primary/25 dark:hover:bg-[#45c3f3]/10 dark:focus-visible:ring-[#45c3f3]/65"
         >
           <img src={expandLogo} alt="" className="size-4" />
         </button>
@@ -2867,7 +2925,7 @@ function TaskAnalysisPanel({
           )}
         >
           <div className={cn("space-y-4 p-4", children && "shrink-0")}>
-            <article className="group/task-details relative overflow-hidden rounded-[4px] bg-[rgba(0,98,217,0.1)] px-4 py-5">
+            <article className="group/task-details relative overflow-hidden rounded-[4px] border border-rose-100 bg-rose-50/70 px-4 py-5 dark:border-transparent dark:bg-[rgba(0,98,217,0.1)]">
               {taskEditable && onEditTask && (
                 <div className="absolute right-2 top-2">
                   <HoverEditButton
@@ -2879,24 +2937,24 @@ function TaskAnalysisPanel({
               )}
               <h3
                 title={desensitize(task.title)}
-                className="pr-8 text-xl font-[550] leading-8 text-white"
+                className="pr-8 text-xl font-[550] leading-8 text-slate-900 dark:text-white"
               >
                 <span className="line-clamp-1">{desensitize(task.title)}</span>
               </h3>
               <p
                 title={desensitize(task.description)}
-                className="mt-3 line-clamp-3 whitespace-pre-wrap text-sm leading-6 text-white"
+                className="mt-3 line-clamp-3 whitespace-pre-wrap text-sm leading-6 text-slate-700 dark:text-white"
               >
                 {desensitize(task.description)}
               </p>
-              <div className="mt-4 space-y-2 border-t border-[rgba(85,166,254,0.16)] pt-3 text-sm text-slate-600 dark:text-[#c5d7ee]">
+              <div className="mt-4 space-y-2 border-t border-rose-100 pt-3 text-sm text-slate-600 dark:border-[rgba(85,166,254,0.16)] dark:text-[#c5d7ee]">
                 <p className="flex min-w-0 items-center gap-2">
-                  <FileText className="size-4 shrink-0 text-[#45c3f3]" strokeWidth={1.8} />
+                  <FileText className="size-4 shrink-0 text-primary dark:text-[#45c3f3]" strokeWidth={1.8} />
                   <span className="shrink-0 text-slate-500 dark:text-[#9ebfe2]">任务来源：</span>
                   <span className="truncate">{desensitize(task.source)}</span>
                 </p>
                 <p className="flex min-w-0 items-center gap-2">
-                  <Clock3 className="size-4 shrink-0 text-[#45c3f3]" strokeWidth={1.8} />
+                  <Clock3 className="size-4 shrink-0 text-primary dark:text-[#45c3f3]" strokeWidth={1.8} />
                   <span className="shrink-0 text-slate-500 dark:text-[#9ebfe2]">下发时间：</span>
                   <span className="truncate">{task.issuedAt || "未设置"}</span>
                 </p>
@@ -2907,7 +2965,7 @@ function TaskAnalysisPanel({
               <div className="relative flex h-10 items-center border-b border-slate-200 dark:border-[#2b8ffe]/60">
                 <span
                   aria-hidden="true"
-                  className="mr-3 h-6 w-1 shrink-0 rounded-l-[2px] rounded-br-[2px] bg-[linear-gradient(167.47deg,#a2e1f9_0%,#45c3f3_100%)]"
+                  className="mr-3 h-6 w-1 shrink-0 rounded-l-[2px] rounded-br-[2px] bg-[linear-gradient(167.47deg,#f15959_0%,#cc1925_100%)] dark:bg-[linear-gradient(167.47deg,#a2e1f9_0%,#45c3f3_100%)]"
                 />
                 <h3 className="text-lg font-[550] tracking-wide text-slate-900 dark:text-white">意图分析</h3>
                 {intentEditable && onEditIntent && (
@@ -2982,10 +3040,10 @@ function TaskInformationCard({
 }) {
   return (
     <section className="group relative shrink-0 overflow-hidden rounded-[4px] border border-[#ECE7E4] bg-white shadow-[0_4px_20px_rgba(0,0,0,0.02)] dark:border-[rgba(43,143,254,0.6)] dark:bg-[#032650] dark:shadow-none">
-      <div className="relative flex h-10 items-center border-b border-slate-200 !bg-[linear-gradient(89.65deg,#0062d9_0.03%,#0062d900_99.97%)] px-4 dark:border-b-[#2b8ffe]/60 dark:after:absolute dark:after:inset-x-0 dark:after:bottom-[-1px] dark:after:h-px dark:after:bg-[#45c3f3]/85 dark:after:content-['']">
+      <div className="relative flex h-10 items-center border-b border-rose-100 bg-[linear-gradient(89.65deg,rgba(245,34,45,0.10)_0.03%,rgba(245,34,45,0)_99.97%)] px-4 [&_h2]:!text-slate-900 dark:!bg-[linear-gradient(89.65deg,#0062d9_0.03%,#0062d900_99.97%)] dark:border-b-[#2b8ffe]/60 dark:[&_h2]:!text-white dark:after:absolute dark:after:inset-x-0 dark:after:bottom-[-1px] dark:after:h-px dark:after:bg-[#45c3f3]/85 dark:after:content-['']">
         <span
           aria-hidden="true"
-          className="mr-3 h-5 w-1 shrink-0 rounded-l-[2px] rounded-br-[2px] bg-[linear-gradient(167.47deg,#a2e1f9_0%,#45c3f3_100%)]"
+          className="mr-3 h-5 w-1 shrink-0 rounded-l-[2px] rounded-br-[2px] bg-[linear-gradient(167.47deg,#f15959_0%,#cc1925_100%)] dark:bg-[linear-gradient(167.47deg,#a2e1f9_0%,#45c3f3_100%)]"
         />
         <h2 className="text-base font-[550] tracking-wide text-white">任务信息</h2>
         <div className="relative z-10 ml-auto flex items-center gap-2">
@@ -2996,7 +3054,7 @@ function TaskInformationCard({
             aria-label={collapsed ? "展开任务信息" : "收起任务信息"}
             aria-expanded={!collapsed}
             onClick={() => onCollapsedChange(!collapsed)}
-            className="flex size-7 shrink-0 items-center justify-center rounded-[4px] transition-colors hover:bg-[#45c3f3]/10 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-[#45c3f3]/65"
+            className="flex size-7 shrink-0 items-center justify-center rounded-[4px] transition-colors hover:bg-primary/10 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-primary/25 dark:hover:bg-[#45c3f3]/10 dark:focus-visible:ring-[#45c3f3]/65"
           >
             <img src={expandLogo} alt="" className="size-4" />
           </button>
@@ -3141,7 +3199,7 @@ function BusinessChainSelector({
       <div className="relative flex h-10 items-center border-b border-slate-200 dark:border-[#2b8ffe]/60">
         <span
           aria-hidden="true"
-          className="mr-3 h-6 w-1 shrink-0 rounded-l-[2px] rounded-br-[2px] bg-[linear-gradient(167.47deg,#a2e1f9_0%,#45c3f3_100%)]"
+          className="mr-3 h-6 w-1 shrink-0 rounded-l-[2px] rounded-br-[2px] bg-[linear-gradient(167.47deg,#f15959_0%,#cc1925_100%)] dark:bg-[linear-gradient(167.47deg,#a2e1f9_0%,#45c3f3_100%)]"
         />
         <h3 className="text-lg font-[550] tracking-wide text-slate-900 dark:text-white">业务链</h3>
         <span className="ml-auto flex size-6 items-center justify-center rounded-[4px] bg-slate-100 text-xs font-semibold tabular-nums text-slate-500 dark:bg-[#0b386d] dark:text-[#83c1ff]">
@@ -3323,10 +3381,10 @@ function IntentUnderstandingCard({
         collapsed ? "flex-none" : "flex-1",
       )}
     >
-      <div className="relative flex h-10 shrink-0 items-center border-b border-slate-200 !bg-[linear-gradient(89.65deg,#0062d9_0.03%,#0062d900_99.97%)] px-4 dark:border-b-[#2b8ffe]/60 dark:after:absolute dark:after:inset-x-0 dark:after:bottom-[-1px] dark:after:h-px dark:after:bg-[#45c3f3]/85 dark:after:content-['']">
+      <div className="relative flex h-10 shrink-0 items-center border-b border-rose-100 bg-[linear-gradient(89.65deg,rgba(245,34,45,0.10)_0.03%,rgba(245,34,45,0)_99.97%)] px-4 [&_h2]:!text-slate-900 dark:!bg-[linear-gradient(89.65deg,#0062d9_0.03%,#0062d900_99.97%)] dark:border-b-[#2b8ffe]/60 dark:[&_h2]:!text-white dark:after:absolute dark:after:inset-x-0 dark:after:bottom-[-1px] dark:after:h-px dark:after:bg-[#45c3f3]/85 dark:after:content-['']">
         <span
           aria-hidden="true"
-          className="mr-3 h-5 w-1 shrink-0 rounded-l-[2px] rounded-br-[2px] bg-[linear-gradient(167.47deg,#a2e1f9_0%,#45c3f3_100%)]"
+          className="mr-3 h-5 w-1 shrink-0 rounded-l-[2px] rounded-br-[2px] bg-[linear-gradient(167.47deg,#f15959_0%,#cc1925_100%)] dark:bg-[linear-gradient(167.47deg,#a2e1f9_0%,#45c3f3_100%)]"
         />
         <h2 className="text-base font-[550] tracking-wide text-white">意图理解</h2>
         <div className="relative z-10 ml-auto flex items-center gap-2">
@@ -3337,7 +3395,7 @@ function IntentUnderstandingCard({
             aria-label={collapsed ? "展开意图理解" : "收起意图理解"}
             aria-expanded={!collapsed}
             onClick={() => onCollapsedChange(!collapsed)}
-            className="flex size-7 shrink-0 items-center justify-center rounded-[4px] transition-colors hover:bg-[#45c3f3]/10 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-[#45c3f3]/65"
+            className="flex size-7 shrink-0 items-center justify-center rounded-[4px] transition-colors hover:bg-primary/10 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-primary/25 dark:hover:bg-[#45c3f3]/10 dark:focus-visible:ring-[#45c3f3]/65"
           >
             <img src={expandLogo} alt="" className="size-4" />
           </button>
@@ -3521,7 +3579,7 @@ function BusinessChainFlow({
           {embedded ? (
             <span
               aria-hidden="true"
-              className="h-6 w-1 shrink-0 rounded-l-[2px] rounded-br-[2px] bg-[linear-gradient(167.47deg,#a2e1f9_0%,#45c3f3_100%)]"
+              className="h-6 w-1 shrink-0 rounded-l-[2px] rounded-br-[2px] bg-[linear-gradient(167.47deg,#f15959_0%,#cc1925_100%)] dark:bg-[linear-gradient(167.47deg,#a2e1f9_0%,#45c3f3_100%)]"
             />
           ) : (
             <span className="flex size-5 shrink-0 items-center justify-center rounded-md bg-primary text-primary-foreground">
diff --git a/frontend-web/src/roundtable-planning/hooks/useStep1Intent.ts b/frontend-web/src/roundtable-planning/hooks/useStep1Intent.ts
index 2c009023..689f3f03 100644
--- a/frontend-web/src/roundtable-planning/hooks/useStep1Intent.ts
+++ b/frontend-web/src/roundtable-planning/hooks/useStep1Intent.ts
@@ -149,6 +149,7 @@ export interface UseStep1IntentReturn {
   hydrateFromDraft: (snapshot: Step1Snapshot) => void;
   /** 给「跳过此项」按钮 / 「继续追问」按钮等本地 demo 操作用。 */
   appendLocalMessage: (msg: InteractiveMessage) => void;
+  clearInteractiveMessages: () => void;
 }
 
 const INTENT_WELCOME_TEXT =
@@ -662,6 +663,12 @@ export function useStep1Intent(options: UseStep1IntentOptions): UseStep1IntentRe
     setInteractiveMessages((prev) => [...prev, msg]);
   }, []);
 
+  const clearInteractiveMessages = useCallback(() => {
+    setInteractiveMessages([]);
+    setPendingIntentClarificationMsgId(null);
+    setIntentClarificationSelections(new Map());
+  }, []);
+
   const updateIntentReady = useCallback((next: IntentSummary) => {
     // 用户手动改完意图 → 覆盖为权威值,并清掉「待澄清」态(已确认意图,无需再答问)。
     setIntentReady(next);
@@ -687,5 +694,6 @@ export function useStep1Intent(options: UseStep1IntentOptions): UseStep1IntentRe
     stopIntentStream,
     hydrateFromDraft,
     appendLocalMessage,
+    clearInteractiveMessages,
   };
 }
diff --git a/frontend-web/src/styles/globals.css b/frontend-web/src/styles/globals.css
index e03014a3..3f56ed9c 100644
--- a/frontend-web/src/styles/globals.css
+++ b/frontend-web/src/styles/globals.css
@@ -602,7 +602,7 @@
   /* 岗位会商左侧业务链：列表较窄，避免滚动条抢占卡片内容宽度。 */
   .business-chain-scrollbar {
     scrollbar-width: thin;
-    scrollbar-color: #2b8ffe transparent;
+    scrollbar-color: rgb(214 36 36 / 0.9) transparent;
   }
 
   .business-chain-scrollbar::-webkit-scrollbar {
@@ -612,6 +612,15 @@
 
   .business-chain-scrollbar::-webkit-scrollbar-thumb {
     border: 0;
+    background: linear-gradient(180deg, rgb(241 89 89 / 0.82), rgb(214 36 36 / 0.9))
+      padding-box;
+  }
+
+  .dark .business-chain-scrollbar {
+    scrollbar-color: #2b8ffe transparent;
+  }
+
+  .dark .business-chain-scrollbar::-webkit-scrollbar-thumb {
     background: linear-gradient(180deg, rgb(85 166 254 / 0.82), rgb(0 98 217 / 0.9))
       padding-box;
   }
diff --git a/offline-backend-20260512/backend/app/gateway/routers/threads.py b/offline-backend-20260512/backend/app/gateway/routers/threads.py
index 6a637378..05522052 100644
--- a/offline-backend-20260512/backend/app/gateway/routers/threads.py
+++ b/offline-backend-20260512/backend/app/gateway/routers/threads.py
@@ -1064,6 +1064,19 @@ class AppendMessageRequest(BaseModel):
     type: str = Field(default="human", description="Message role: human/ai/system")
 
 
+class EditMessageRequest(BaseModel):
+    """Request body for editing one persisted chat message."""
+
+    content: str = Field(..., description="Replacement message text")
+
+    @field_validator("content")
+    @classmethod
+    def _content_not_blank(cls, value: str) -> str:
+        if not value.strip():
+            raise ValueError("Message content cannot be empty")
+        return value
+
+
 def _flatten_msg_content(content: Any) -> str:
     """把 message.content(str / 结构化 block 列表)拍平成纯文本。"""
     if isinstance(content, str):
@@ -1079,6 +1092,17 @@ def _flatten_msg_content(content: Any) -> str:
     return str(content) if content else ""
 
 
+def _set_message_content(message: Any, content: str) -> None:
+    """Replace a message's visible content while preserving id/metadata/files."""
+    if isinstance(message, dict):
+        message["content"] = content
+        return
+    try:
+        setattr(message, "content", content)
+    except Exception as exc:
+        raise TypeError("Message content cannot be edited") from exc
+
+
 def _extract_last_ai_text(messages: list[Any]) -> str:
     """返回最后一条 AI 消息的纯文本;没有则空串。兼容 message 对象与序列化 dict 两种存储形态。"""
     for msg in reversed(messages or []):
@@ -1176,6 +1200,64 @@ async def get_thread_last_ai_message(thread_id: str, request: Request, max_chars
     return {"delivered": full_len > 0, "content": text, "length": full_len}
 
 
+@router.delete("/{thread_id}/messages")
+@require_permission("threads", "write", owner_check=True, require_existing=True)
+async def clear_thread_messages(thread_id: str, request: Request) -> dict[str, Any]:
+    """Clear all messages from a thread's latest checkpoint."""
+    checkpointer = get_checkpointer(request)
+    config: dict[str, Any] = {
+        "configurable": {
+            "thread_id": thread_id,
+            "checkpoint_ns": "",
+        }
+    }
+    try:
+        checkpoint_tuple = await checkpointer.aget_tuple(config)
+    except Exception:
+        logger.exception("Failed to get state for thread %s", sanitize_log_param(thread_id))
+        raise HTTPException(status_code=500, detail="Failed to get thread state")
+
+    if checkpoint_tuple is None:
+        raise HTTPException(status_code=404, detail=f"Thread {thread_id} not found")
+
+    checkpoint: dict[str, Any] = dict(getattr(checkpoint_tuple, "checkpoint", {}) or {})
+    metadata: dict[str, Any] = dict(getattr(checkpoint_tuple, "metadata", {}) or {})
+    channel_values: dict[str, Any] = dict(checkpoint.get("channel_values", {}))
+
+    messages = channel_values.get("messages")
+    if not isinstance(messages, list):
+        messages = []
+
+    deleted_ids = [mid for m in messages if (mid := _message_id(m))]
+    channel_values["messages"] = []
+    checkpoint["channel_values"] = channel_values
+    checkpoint["id"] = str(uuid6(clock_seq=-2))
+    checkpoint["ts"] = now_iso()
+    versions = dict(checkpoint.get("channel_versions", {}))
+    new_ver = checkpointer.get_next_version(versions.get("messages"), None)
+    versions["messages"] = new_ver
+    checkpoint["channel_versions"] = versions
+    metadata["updated_at"] = now_iso()
+
+    try:
+        await checkpointer.aput(config, checkpoint, metadata, {"messages": new_ver})
+    except Exception:
+        logger.exception("Failed to clear messages from thread %s", sanitize_log_param(thread_id))
+        raise HTTPException(status_code=500, detail="Failed to clear thread messages")
+
+    logger.info(
+        "Cleared %d message(s) from thread %s",
+        len(messages),
+        sanitize_log_param(thread_id),
+    )
+    return {
+        "ok": True,
+        "deleted_ids": deleted_ids,
+        "deleted_count": len(messages),
+        "remaining": 0,
+    }
+
+
 @router.delete("/{thread_id}/messages/{message_id}")
 @require_permission("threads", "write", owner_check=True, require_existing=True)
 async def delete_thread_message(thread_id: str, message_id: str, request: Request) -> dict[str, Any]:
@@ -1266,6 +1348,88 @@ async def delete_thread_message(thread_id: str, message_id: str, request: Reques
     return {"ok": True, "deleted_ids": deleted_ids, "remaining": len(filtered)}
 
 
+@router.patch("/{thread_id}/messages/{message_id}")
+@require_permission("threads", "write", owner_check=True, require_existing=True)
+async def edit_thread_message(
+    thread_id: str,
+    message_id: str,
+    body: EditMessageRequest,
+    request: Request,
+) -> dict[str, Any]:
+    """Edit one message in a thread's latest checkpoint.
+
+    This is intentionally narrower than ``POST /state``: callers send only the
+    target id and replacement text, while the server preserves all other
+    message fields (attachments, timestamps, tool metadata, ids) and bumps the
+    ``messages`` channel version so the edited checkpoint is durable.
+    """
+    checkpointer = get_checkpointer(request)
+    config: dict[str, Any] = {
+        "configurable": {
+            "thread_id": thread_id,
+            "checkpoint_ns": "",
+        }
+    }
+    try:
+        checkpoint_tuple = await checkpointer.aget_tuple(config)
+    except Exception:
+        logger.exception("Failed to get state for thread %s", sanitize_log_param(thread_id))
+        raise HTTPException(status_code=500, detail="Failed to get thread state")
+
+    if checkpoint_tuple is None:
+        raise HTTPException(status_code=404, detail=f"Thread {thread_id} not found")
+
+    checkpoint: dict[str, Any] = dict(getattr(checkpoint_tuple, "checkpoint", {}) or {})
+    metadata: dict[str, Any] = dict(getattr(checkpoint_tuple, "metadata", {}) or {})
+    channel_values: dict[str, Any] = dict(checkpoint.get("channel_values", {}))
+    messages = list(channel_values.get("messages") or [])
+    if not messages:
+        raise HTTPException(status_code=404, detail="Thread has no messages")
+
+    target_index = next(
+        (i for i, m in enumerate(messages) if _message_id(m) == message_id),
+        None,
+    )
+    if target_index is None:
+        raise HTTPException(status_code=404, detail=f"Message {message_id} not found")
+
+    try:
+        _set_message_content(messages[target_index], body.content)
+    except TypeError as exc:
+        raise HTTPException(status_code=422, detail=str(exc)) from exc
+
+    channel_values["messages"] = messages
+    checkpoint["channel_values"] = channel_values
+    checkpoint["id"] = str(uuid6(clock_seq=-2))
+    checkpoint["ts"] = now_iso()
+    versions = dict(checkpoint.get("channel_versions", {}))
+    new_ver = checkpointer.get_next_version(versions.get("messages"), None)
+    versions["messages"] = new_ver
+    checkpoint["channel_versions"] = versions
+    metadata["updated_at"] = now_iso()
+
+    try:
+        await checkpointer.aput(config, checkpoint, metadata, {"messages": new_ver})
+    except Exception:
+        logger.exception(
+            "Failed to edit message %s from thread %s",
+            sanitize_log_param(message_id),
+            sanitize_log_param(thread_id),
+        )
+        raise HTTPException(status_code=500, detail="Failed to edit message")
+
+    serialized_messages = serialize_channel_values({"messages": [messages[target_index]]}).get("messages", [])
+    logger.info(
+        "Edited message %s in thread %s",
+        sanitize_log_param(message_id),
+        sanitize_log_param(thread_id),
+    )
+    return {
+        "ok": True,
+        "message": serialized_messages[0] if serialized_messages else {"id": message_id, "content": body.content},
+    }
+
+
 @router.post("/{thread_id}/history", response_model=list[HistoryEntry])
 @require_permission("threads", "read", owner_check=True)
 async def get_thread_history(thread_id: str, body: ThreadHistoryRequest, request: Request) -> list[HistoryEntry]: