feat: 删除提问时级联删除其回答，并移除回答上的删除按钮

- 删除按钮只保留在用户提问气泡上；AI 回答不再单独提供删除
- 后端 DELETE /messages/{id} 改为按整轮删除：从提问删到下一条提问之前，
  返回实际删除的 deleted_ids，保持 checkpoint 合法（无孤立工具结果/回答）
- 前端隐藏后端返回的整批 id，删除后即时消失
- 更新删除相关中英文案

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend-web/src/components/workspace/messages/delete-message-button.tsx

@@ -17,10 +17,11 @@ import { useDeleteMessage } from "@/core/threads/hooks";
 import { Tooltip } from "../tooltip";
 
 /**
- * Hover affordance that deletes a single message (a user question or an
- * assistant answer) after a confirmation step. The actual removal is persisted
- * server-side; `onDeleted` lets the parent hide the bubble immediately without
- * waiting for the stream cache to refresh.
+ * Hover affordance that deletes a conversation turn (a user question together
+ * with its answer) after a confirmation step. The actual removal is persisted
+ * server-side; `onDeleted` receives the ids the server removed so the parent
+ * can hide those bubbles immediately without waiting for the stream cache to
+ * refresh.
  */
 export function DeleteMessageButton({
   threadId,
@@ -30,7 +31,7 @@ export function DeleteMessageButton({
 }: {
   threadId: string;
   messageId: string;
-  onDeleted?: () => void;
+  onDeleted?: (deletedIds: string[]) => void;
   className?: string;
 }) {
   const { t } = useI18n();
@@ -39,8 +40,11 @@ export function DeleteMessageButton({
 
   const handleConfirm = async () => {
     try {
-      await deleteMessage.mutateAsync({ threadId, messageId });
-      onDeleted?.();
+      const deletedIds = await deleteMessage.mutateAsync({
+        threadId,
+        messageId,
+      });
+      onDeleted?.(deletedIds);
       setOpen(false);
     } catch (error) {
       toast.error(

frontend-web/src/components/workspace/messages/message-list-item.tsx

@@ -147,18 +147,13 @@ export function MessageListItem({
   displaySources?: RuntimeDisplaySource[];
   extraRehypePlugins?: ReturnType<typeof useRehypeSplitWordsIntoSpans>;
   onEditResubmit?: (text: string) => void;
-  onMessageDeleted?: (messageId: string) => void;
+  onMessageDeleted?: (deletedIds: string[]) => void;
 }) {
   const isHuman = message.type === 'human';
   const messageMarkdown =
     extractContentFromMessage(message) ??
     extractReasoningContentFromMessage(message) ??
     '';
-  // Deletion is offered only for messages that already exist server-side
-  // (real, non-optimistic ids). Optimistic placeholders (`opt-*`) have no
-  // checkpoint entry to remove.
-  const canDelete =
-    !!onMessageDeleted && !!message.id && !message.id.startsWith('opt-');
   return (
     <AIElementMessage
       className={cn(
@@ -200,13 +195,6 @@ export function MessageListItem({
                 fileName="message"
               />
             )}
-            {canDelete && (
-              <DeleteMessageButton
-                threadId={threadId}
-                messageId={message.id!}
-                onDeleted={() => onMessageDeleted?.(message.id!)}
-              />
-            )}
           </div>
         </MessageToolbar>
       )}
@@ -389,7 +377,7 @@ function MessageContent_({
   displaySources?: RuntimeDisplaySource[];
   extraRehypePlugins?: ReturnType<typeof useRehypeSplitWordsIntoSpans>;
   onEditResubmit?: (text: string) => void;
-  onMessageDeleted?: (messageId: string) => void;
+  onMessageDeleted?: (deletedIds: string[]) => void;
 }) {
   const baseRehypePlugins = useRehypeSplitWordsIntoSpans(isLoading);
 
@@ -521,6 +509,9 @@ function MessageContent_({
   }
 
   if (isHuman) {
+    // Only the user's own question carries a delete affordance, and only once
+    // it exists server-side (real, non-optimistic id). Deleting it cascades to
+    // its answer on the backend.
     const canDelete =
       !!onMessageDeleted && !!message.id && !message.id.startsWith('opt-');
     return (
@@ -536,7 +527,7 @@ function MessageContent_({
             <DeleteMessageButton
               threadId={threadId}
               messageId={message.id!}
-              onDeleted={() => onMessageDeleted?.(message.id!)}
+              onDeleted={(ids) => onMessageDeleted?.(ids)}
               className="size-6"
             />
           ) : null

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

@@ -104,10 +104,11 @@ export function MessageList({
   useEffect(() => {
     setHiddenMessageIds(new Set());
   }, [threadId]);
-  const handleMessageDeleted = useCallback((messageId: string) => {
+  const handleMessageDeleted = useCallback((deletedIds: string[]) => {
+    if (deletedIds.length === 0) return;
     setHiddenMessageIds((prev) => {
       const next = new Set(prev);
-      next.add(messageId);
+      for (const id of deletedIds) next.add(id);
       return next;
     });
   }, []);

frontend-web/src/core/i18n/locales/en-US.ts

@@ -82,9 +82,10 @@ export const enUS: Translations = {
   inputBox: {
     placeholder: "How can I assist you today?",
     editQuestion: "Edit question",
-    deleteMessage: "Delete message",
-    deleteMessageConfirmTitle: "Delete this message?",
-    deleteMessageConfirmDescription: "This action cannot be undone.",
+    deleteMessage: "Delete question and answer",
+    deleteMessageConfirmTitle: "Delete this question and its answer?",
+    deleteMessageConfirmDescription:
+      "The question and its answer will both be removed. This cannot be undone.",
     createSkillPrompt:
       "We're going to build a new skill step by step with `skill-creator`. To start, what do you want this skill to do?",
     addAttachments: "Add attachments",

frontend-web/src/core/i18n/locales/zh-CN.ts

@@ -82,9 +82,9 @@ export const zhCN: Translations = {
   inputBox: {
     placeholder: "今天我能为你做些什么？",
     editQuestion: "编辑问题",
-    deleteMessage: "删除消息",
-    deleteMessageConfirmTitle: "删除这条消息？",
-    deleteMessageConfirmDescription: "删除后将无法恢复。",
+    deleteMessage: "删除提问及回答",
+    deleteMessageConfirmTitle: "删除该提问及其回答？",
+    deleteMessageConfirmDescription: "该提问及对应的回答都会被删除，且无法恢复。",
     createSkillPrompt:
       "我们一起用 skill-creator 技能来创建一个技能吧。先问问我希望这个技能能做什么。",
     addAttachments: "添加附件",

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

@@ -805,11 +805,13 @@ export function useDeleteThread() {
 }
 
 /**
- * Delete a single message (a user question or an assistant answer) from a
- * thread. Hits the Gateway endpoint that filters the message out of the latest
- * checkpoint. The live `useStream` cache is not auto-refreshed by this call —
- * callers hide the deleted id locally (see `MessageList`) so the removal shows
- * immediately; a reload then reads the persisted, already-trimmed state.
+ * Delete a conversation turn (a user question together with its answer) from a
+ * thread. Hits the Gateway endpoint that removes the question and every
+ * following message up to the next question from the latest checkpoint, and
+ * returns the ids that were actually removed. The live `useStream` cache is not
+ * auto-refreshed by this call — callers hide the returned ids locally (see
+ * `MessageList`) so the removal shows immediately; a reload then reads the
+ * persisted, already-trimmed state.
  */
 export function useDeleteMessage() {
   return useMutation({
@@ -819,7 +821,7 @@ export function useDeleteMessage() {
     }: {
       threadId: string;
       messageId: string;
-    }) => {
+    }): Promise<string[]> => {
       const response = await apiFetch(
         `${getBackendBaseURL()}/api/threads/${encodeURIComponent(
           threadId,
@@ -835,6 +837,12 @@ export function useDeleteMessage() {
           .catch(() => ({ detail: "删除消息失败。" }));
         throw new Error(error.detail ?? "删除消息失败。");
       }
+
+      const body = (await response.json().catch(() => ({}))) as {
+        deleted_ids?: string[];
+      };
+      // Fall back to the requested id so the caller can always hide something.
+      return body.deleted_ids?.length ? body.deleted_ids : [messageId];
     },
   });
 }

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

@@ -1012,13 +1012,16 @@ async def update_thread_state(thread_id: str, body: ThreadStateUpdateRequest, re
 @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]:
-    """Delete a single message (a user question or an assistant answer) from a
-    thread's latest checkpoint.
+    """Delete a conversation turn from a thread's latest checkpoint.
 
-    Filters the message whose ``id`` matches ``message_id`` out of the
-    ``messages`` channel and writes a fresh checkpoint. The remaining messages
-    keep their original ``BaseMessage`` objects (mirroring
-    :func:`update_thread_state`), so the graph can still resume the thread.
+    ``message_id`` identifies a user question. The whole turn is removed: the
+    question plus every following message (its answer and any tool/intermediate
+    messages) up to — but not including — the next user question. Removing a
+    complete turn keeps the remaining checkpoint valid (no orphaned tool
+    results / dangling answers) and lets the graph still resume the thread.
+
+    If ``message_id`` points at a non-human message, only that single message is
+    removed.
     """
     checkpointer = get_checkpointer(request)
 
@@ -1045,10 +1048,28 @@ async def delete_thread_message(thread_id: str, message_id: str, request: Reques
     if not isinstance(messages, list):
         raise HTTPException(status_code=404, detail="Thread has no messages")
 
-    filtered = [m for m in messages if _message_id(m) != message_id]
-    if len(filtered) == len(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")
 
+    # Delete the whole turn: from the question to just before the next question.
+    end = len(messages)
+    if _message_type(messages[target_index]) == "human":
+        for j in range(target_index + 1, len(messages)):
+            if _message_type(messages[j]) == "human":
+                end = j
+                break
+    else:
+        end = target_index + 1
+
+    deleted_ids = [
+        mid for m in messages[target_index:end] if (mid := _message_id(m))
+    ]
+    filtered = messages[:target_index] + messages[end:]
+
     channel_values["messages"] = filtered
     checkpoint["channel_values"] = channel_values
     metadata["updated_at"] = now_iso()
@@ -1070,11 +1091,12 @@ async def delete_thread_message(thread_id: str, message_id: str, request: Reques
         raise HTTPException(status_code=500, detail="Failed to delete message")
 
     logger.info(
-        "Deleted message %s from thread %s",
+        "Deleted turn starting at message %s (%d message(s)) from thread %s",
         sanitize_log_param(message_id),
+        len(messages) - len(filtered),
         sanitize_log_param(thread_id),
     )
-    return {"ok": True, "deleted": message_id, "remaining": len(filtered)}
+    return {"ok": True, "deleted_ids": deleted_ids, "remaining": len(filtered)}
 
 
 @router.post("/{thread_id}/history", response_model=list[HistoryEntry])