diff --git a/apps/chat/serializers/chat.py b/apps/chat/serializers/chat.py
index c01a0a9f6aa..06d2bcf3029 100644
--- a/apps/chat/serializers/chat.py
+++ b/apps/chat/serializers/chat.py
@@ -58,7 +58,6 @@
 from models_provider.tools import get_model_instance_by_model_workspace_id
 from system_manage.models.chat_user_token_quota import ChatUserTokenQuota
 
-# 「Chat 行尚未查询」的哨兵，区别于「查询过但不存在(None)」
 _CHAT_UNSET = object()
 
 
@@ -200,13 +199,10 @@ def ensure_chat_row(self, question, asker):
         self._chat_cache = chat
         return chat
 
-    def save_chat_record(self, chat_record_id, question, asker, new_record):
-        """插入一条占位 ChatRecord（workflow 完成后由 update_chat_record 回填）。"""
-        chat_id = self.data.get("chat_id")
-        q_text = question.get("content", "") if isinstance(question, dict) else question
-        self.ensure_chat_row(q_text, asker)
-        defaults = {
-            "chat_id": chat_id,
+    def get_defaults_record(self, question):
+        """构造一条占位 ChatRecord 的字段（workflow 完成后由 update_chat_record 回填）。"""
+        return {
+            "chat_id": self.data.get("chat_id"),
             "problem_text": "",
             "answer_text": "",
             "details": {},
@@ -222,12 +218,6 @@ def save_chat_record(self, chat_record_id, question, asker, new_record):
             "question": question,
             "messages": [],
         }
-        if new_record:
-            # 全新记录：直接插入，省掉 update_or_create 的一次 SELECT
-            ChatRecord(id=chat_record_id, **defaults).save(force_insert=True)
-        else:
-            # Form 提交 / 重答：复用同一 chat_record_id
-            QuerySet(ChatRecord).update_or_create(id=chat_record_id, defaults=defaults)
 
     @staticmethod
     def _usage_from_context(workflow_context):
@@ -288,6 +278,9 @@ def chat_work_flow(self, application, instance: dict, base_to_response):
         workflow = new_instance(work_flow, WorkflowType.APPLICATION)
 
         chat_record_id_str = str(uuid.uuid7()) if chat_record_id is None else str(chat_record_id)
+        self.ensure_chat_row(message, chat_user)
+        if chat_record_id is None:
+            ChatRecord(id=chat_record_id_str, **self.get_defaults_record(message_dict)).save(force_insert=True)
 
         parameters = {
             "history_chat_record": history_chat_record,
@@ -317,12 +310,10 @@ def chat_work_flow(self, application, instance: dict, base_to_response):
 
         result_queue = queue.Queue()
         aggregation = AggregationManager()
-        self.save_chat_record(chat_record_id_str, message_dict, chat_user, new_record=chat_record_id is None)
 
         def on_next(wf_manage, content):
             aggregation.aggregate(content)
             block = content.to_dict()
-            # 持久化(resume)与 live 队列都放裸内容块，格式化统一交给消费端的 base_to_response
             get_message_queue().produce(chat_record_id_str, block)
             result_queue.put(("chunk", block))
 
@@ -337,9 +328,7 @@ def on_complete(wf_manage, error):
                 )
             messages = aggregation.get_contents()
             self.update_chat_record(chat_user_id, chat_record_id_str, wf_manage.context, messages)
-            # 计数统计放到内容落库之后再更新（挪出进对话前的关键路径）
             ChatCountSerializer(data={"chat_id": chat_id}).update_chat()
-            # 定稿后把本轮记录追加进历史缓存（question 已在建占位时确定，messages 为聚合结果）
             ChatHistory(chat_id).append(
                 ChatRecord(
                     id=chat_record_id_str,
@@ -403,7 +392,6 @@ def generate():
                         yield "data: [DONE]\n\n"
                         break
                     if msg_type == "chunk":
-                        # data 是裸内容块(content.to_dict())，格式化交给 base_to_response
                         frame = base_to_response.to_stream(chat_id, chat_record_id_str, data)
                         if frame is not None:
                             yield "data: " + frame + "\n\n"
diff --git a/apps/common/handle/impl/response/system_to_response.py b/apps/common/handle/impl/response/system_to_response.py
index 29243613ae4..daabc6cc1b5 100644
--- a/apps/common/handle/impl/response/system_to_response.py
+++ b/apps/common/handle/impl/response/system_to_response.py
@@ -23,7 +23,7 @@ def to_stream(self, chat_id, chat_record_id, block: dict):
             {
                 "chat_id": str(chat_id),
                 "chat_record_id": str(chat_record_id),
-                "content": [block],
+                "content": [{**block, "chat_id": str(chat_id), "chat_record_id": str(chat_record_id)}],
             },
             ensure_ascii=False,
         )
diff --git a/ui/src/components/conversation/chat-panel/index.vue b/ui/src/components/conversation/chat-panel/index.vue
index 43e93d5b71a..92dfa0617a7 100644
--- a/ui/src/components/conversation/chat-panel/index.vue
+++ b/ui/src/components/conversation/chat-panel/index.vue
@@ -236,7 +236,7 @@
 </template>
 
 <script setup lang="ts">
-import { ref, computed, nextTick, watch, onMounted, reactive } from 'vue'
+import { ref, computed, nextTick, watch, onMounted, reactive, provide } from 'vue'
 import { CircleCloseFilled, Paperclip, Promotion, VideoPause } from '@element-plus/icons-vue'
 import ContentList from '../content-list/index.vue'
 import Loading from '../loading/index.vue'
@@ -364,10 +364,8 @@ const addFile = (file: File) => {
 
   const uploadPromise = (async () => {
     try {
-      let cid = currentChatId.value
-      if (!cid) {
-        cid = store.newChat()
-      }
+      // 惰性取当前 chat_id（幂等），保证文件 source_id 与后续发送的 chat_id 一致
+      const cid = store.getChatId()
       const result = await store.uploadFile(file, cid)
       item.url = result.url
       const parts = result.url.split('/')
@@ -446,19 +444,15 @@ const send = async () => {
 
     const text = question.value.content.trim()
 
-    // 没有当前对话时本地生成草稿 chat_id（后端首发时 open-if-missing）
-    if (!currentChatId.value) {
-      store.newChat()
-    }
-
-    const cid = currentChatId.value
+    // 惰性取 chat_id（无则前端生成，后端首发时 open-if-missing）
+    const cid = store.getChatId()
 
-    // 首条消息：乐观更新草稿标题；落库交给流结束后的后台 renameChat
+    // 首条消息：此刻才把会话 push 进左侧列表（新建时不 push），标题用 question 内容乐观更新；
+    // 落库交给流结束后的后台 renameChat。
     const isFirstMessage = messages.value.length === 0
     const abstract = text.substring(0, 256)
-    if (isFirstMessage && text) {
-      const conv = store.conversations.value.find((c: any) => c.id === cid)
-      if (conv) conv.abstract = abstract
+    if (isFirstMessage && !store.conversations.value.some((c: any) => c.id === cid)) {
+      store.conversations.value.unshift({ id: cid, abstract: text ? abstract : '新对话' })
     }
 
     // 分类文件
@@ -478,54 +472,27 @@ const send = async () => {
       .filter((f) => !isImage(f.name) && !isDocument(f.name) && !isAudio(f.name) && !isVideo(f.name))
       .map((f) => ({ url: f.url, file_id: f.file_id, name: f.name }))
 
-    // 构建 question content
+    // 构建 question content（USER 气泡展示用）与 API message（发后端用）
     const questionContent: any = { type: 'QUESTION', content: text }
-    if (images.length) questionContent.image_list = images
-    if (documents.length) questionContent.document_list = documents
-    if (audio.length) questionContent.audio_list = audio
-    if (video.length) questionContent.video_list = video
-    if (other.length) questionContent.other_list = other
-
-    store.pushMessage({
-      role: 'USER',
-      content: [questionContent],
-      id: nanoid(),
-    })
-
-    store.pushMessage(store.createAnswerMessage())
-    const aiMsg = messages.value[messages.value.length - 1]
-    if (!aiMsg) return
-
-    // 构建 API payload
     const message: any = { content: text, type: 'QUESTION' }
-    if (images.length) message.image_list = images
-    if (documents.length) message.document_list = documents
-    if (audio.length) message.audio_list = audio
-    if (video.length) message.video_list = video
-    if (other.length) message.other_list = other
-
-    const payload: any = { message, stream: true, re_chat: false }
-
-    loading.value = true
-    store.startStream({
-      cid,
-      request: () => store.chat(cid, payload),
-      onStream: (chunk) => {
-        store.appendChunk(aiMsg, chunk)
-        scrollToBottom()
-      },
+    if (images.length) questionContent.image_list = message.image_list = images
+    if (documents.length) questionContent.document_list = message.document_list = documents
+    if (audio.length) questionContent.audio_list = message.audio_list = audio
+    if (video.length) questionContent.video_list = message.video_list = video
+    if (other.length) questionContent.other_list = message.other_list = other
+
+    // 委托通用 sendMessage：新问答（新增 USER 气泡 + 新 answer 消息），
+    // 首条消息落库后把真实标题写回后端交给 onFinish。
+    sendMessage({
+      message,
+      newQuestion: true,
+      questionContent,
+      reChat: false,
       onFinish: () => {
-        scrollToBottom()
-        loading.value = false
-        // 首条消息落库后，把真实标题写回后端（此时会话已被 open-if-missing 建好）
         if (isFirstMessage && text) {
           store.renameChat(cid, abstract).catch(() => {})
         }
       },
-      onFailure: () => {
-        scrollToBottom()
-        loading.value = false
-      },
     })
     question.value.content = ''
     clearFiles()
@@ -592,6 +559,79 @@ watch(
   },
 )
 
+// 新建/切换会话时清空暂存文件与输入，避免文件的 source_id 与新 chat_id 对不上
+watch(
+  () => store.composerResetSignal.value,
+  () => {
+    clearFiles()
+    question.value.content = ''
+  },
+)
+
+// ── 通用发起对话（注入给内容组件） ──────────────────────────
+// 表单提交、以及未来任何“能发起对话”的内容组件都通过它发起/续跑一次对话。
+// 调用方只需显式声明 newQuestion：是否新增一个 question（新 USER 气泡 + 新 answer 消息），
+// 否则续跑聚合回已存在的那条 assistant 消息（后端复用同一 chat_record）。
+interface SendMessageOptions {
+  message: any // 后端 message dict {content,type,image_list?,...}
+  newQuestion: boolean
+  questionContent?: any // newQuestion=true 时 USER 气泡展示的 content 项，缺省用 message
+  reChat?: boolean // 默认 false；新引擎下仅影响知识节点“换答案”去重
+  formData?: Record<string, any>
+  position?: any
+  chatRecordId?: string | null
+  chunkId?: string | null
+  onFinish?: () => void // 收尾钩子（如首条消息落库改标题），在内置结束逻辑后调用
+  onFailure?: () => void
+}
+
+const sendMessage = (opts: SendMessageOptions) => {
+  const cid = store.getChatId()
+
+  // 定位流式写入目标消息
+  let target: any
+  if (opts.newQuestion) {
+    store.pushMessage({ role: 'USER', content: [opts.questionContent ?? opts.message], id: nanoid() })
+    store.pushMessage(store.createAnswerMessage())
+    target = messages.value[messages.value.length - 1]
+  } else {
+    // 续跑：reload 后按 `${chat_record_id}_ASSISTANT` 命中；实时流中 answer 消息 id 为 '' → 回退最后一条
+    target =
+      messages.value.find((m: any) => m.id === `${opts.chatRecordId}_ASSISTANT`) ||
+      messages.value[messages.value.length - 1]
+  }
+  if (!target) return
+
+  const payload: any = { message: opts.message, stream: true, re_chat: opts.reChat ?? false }
+  if (opts.formData) payload.form_data = opts.formData
+  if (opts.position !== undefined) payload.position = opts.position
+  if (opts.chatRecordId) payload.chat_record_id = opts.chatRecordId
+  if (opts.chunkId) payload.chunk_id = opts.chunkId
+
+  loading.value = true
+  store.startStream({
+    cid,
+    request: () => store.chat(cid, payload),
+    onStream: (chunk: any) => {
+      store.appendChunk(target, chunk)
+      scrollToBottom()
+    },
+    onFinish: () => {
+      target.write_ed = true
+      loading.value = false
+      scrollToBottom()
+      opts.onFinish?.()
+    },
+    onFailure: () => {
+      target.write_ed = true
+      loading.value = false
+      opts.onFailure?.()
+    },
+  })
+}
+
+provide('sendMessage', sendMessage)
+
 defineExpose({ scrollToBottom })
 </script>
 
diff --git a/ui/src/components/conversation/common/use-chat-store/chat/index.ts b/ui/src/components/conversation/common/use-chat-store/chat/index.ts
index 35d1807c9b8..dee38731556 100644
--- a/ui/src/components/conversation/common/use-chat-store/chat/index.ts
+++ b/ui/src/components/conversation/common/use-chat-store/chat/index.ts
@@ -10,6 +10,9 @@ import type { ChatMessage } from '../../types'
 // ── 共享状态（单例） ─────────────────────────────────────
 const appInfo = ref<{ name: string; icon: string } | null>(null)
 const currentChatId = ref('')
+// composer 重置信号：新建/切换会话时自增，chat-panel 监听后清空暂存文件与输入，
+// 避免上传文件（source_id 绑旧 chat_id）在切上下文后与新 chat_id 对不上。
+const composerResetSignal = ref(0)
 
 // ── 会话 CRUD ─────────────────────────────────────────
 const { conversations, loadConversations, loadMore } = useConversationCrud({
@@ -78,16 +81,13 @@ export function useChatStore() {
   })
 
   // ── 会话操作 ─────────────────────────────────────────
-  // 本地新建：前端直接生成 chat_id（草稿），不预先请求后端 open；
-  // 首次发消息 / 上传时后端会按该 id 现开会话（open-if-missing）。
-  const newChat = (): string => {
-    const id = crypto.randomUUID()
-    currentChatId.value = id
-    resetMsgState()
-    if (!conversations.value.some((c) => c.id === id)) {
-      conversations.value.unshift({ id, abstract: '新建对话' })
-    }
-    return id
+  // 惰性获取当前 chat_id：已有则原样返回；为空才前端生成一个并赋值。
+  // 幂等——反复调用返回同一个 id，从而上传文件的 source_id 与后续发送的 chat_id 始终一致。
+  // 不请求后端 open，不往左侧列表 push（直到首次发消息才入列表，见 chat-panel send）。
+  const getChatId = (): string => {
+    if (currentChatId.value) return currentChatId.value
+    currentChatId.value = crypto.randomUUID()
+    return currentChatId.value
   }
 
   const openChat = async (appId?: string) => {
@@ -114,26 +114,6 @@ export function useChatStore() {
     return { url: res, name: file.name }
   }
 
-  // ── 发送消息 ─────────────────────────────────────────
-  const sendMessage = (cid: string, payload: any, aiMsg: ChatMessage) => {
-    loading.value = true
-    streamManager.startStream({
-      cid,
-      request: () => chat(cid, payload),
-      onStream: (chunk) => {
-        appendChunk(aiMsg, chunk)
-      },
-      onFinish: () => {
-        aiMsg.write_ed = true
-        loading.value = false
-      },
-      onFailure: () => {
-        aiMsg.write_ed = true
-        loading.value = false
-      }
-    })
-  }
-
   // ── 切换对话 ─────────────────────────────────────────
   const switchConversation = async (cid: string) => {
     await streamManager.switchConversation({
@@ -169,7 +149,7 @@ export function useChatStore() {
     // 会话
     loadConversations,
     loadMore,
-    newChat,
+    getChatId,
     openChat,
     deleteChat,
     renameChat,
@@ -183,7 +163,6 @@ export function useChatStore() {
     appendChunk,
     // 流式
     chat,
-    sendMessage,
     startStream: streamManager.startStream,
     switchConversation,
     closeStream: streamManager.closeStream,
@@ -191,5 +170,10 @@ export function useChatStore() {
     cancelWorkflow: (cid: string) => streamManager.cancelWorkflow(cid, 'chat'),
     // 文件
     uploadFile,
+    // composer 重置
+    composerResetSignal,
+    resetComposer: () => {
+      composerResetSignal.value++
+    },
   }
 }
diff --git a/ui/src/components/conversation/common/use-chat-store/debug/index.ts b/ui/src/components/conversation/common/use-chat-store/debug/index.ts
index 90ec0982995..6ffea95fdd8 100644
--- a/ui/src/components/conversation/common/use-chat-store/debug/index.ts
+++ b/ui/src/components/conversation/common/use-chat-store/debug/index.ts
@@ -10,6 +10,9 @@ import type { ChatMessage } from '../../types'
 // ── 共享状态（单例） ─────────────────────────────────────
 const appInfo = ref<{ name: string; icon: string } | null>(null)
 const currentChatId = ref('')
+// composer 重置信号：新建/切换会话时自增，chat-panel 监听后清空暂存文件与输入，
+// 避免上传文件（source_id 绑旧 chat_id）在切上下文后与新 chat_id 对不上。
+const composerResetSignal = ref(0)
 let currentApplicationId = ''
 const loading = ref<boolean>(false)
 
@@ -87,16 +90,13 @@ export function useDebugStore() {
   })
 
   // ── 会话操作 ─────────────────────────────────────────
-  // 本地新建：前端直接生成 chat_id（草稿），不预先请求后端 open；
-  // 首次发消息 / 上传时后端会按该 id 现开会话（open-if-missing）。
-  const newChat = (): string => {
-    const id = crypto.randomUUID()
-    currentChatId.value = id
-    resetMsgState()
-    if (!conversations.value.some((c) => c.id === id)) {
-      conversations.value.unshift({ id, abstract: '新建对话' })
-    }
-    return id
+  // 惰性获取当前 chat_id：已有则原样返回；为空才前端生成一个并赋值。
+  // 幂等——反复调用返回同一个 id，从而上传文件的 source_id 与后续发送的 chat_id 始终一致。
+  // 不请求后端 open，不往左侧列表 push（直到首次发消息才入列表，见 chat-panel send）。
+  const getChatId = (): string => {
+    if (currentChatId.value) return currentChatId.value
+    currentChatId.value = crypto.randomUUID()
+    return currentChatId.value
   }
 
   const openChat = async (appId?: string) => {
@@ -120,10 +120,8 @@ export function useDebugStore() {
   // ── 文件上传 ─────────────────────────────────────────
   const uploadFile = async (file: File, chatId: string): Promise<{ url: string; name: string }> => {
     loading.value = true
-    let cid = chatId
-    if (!cid) {
-      cid = await openChat(applicationId.value)
-    }
+    // 无会话时前端生成草稿 chat_id（不调后端 open），与发送保持同一个 id。
+    const cid = chatId || getChatId()
     const res = await debugApi.uploadFile(file, cid)
     loading.value = false
     return { url: res, name: file.name }
@@ -163,7 +161,7 @@ export function useDebugStore() {
     // 会话
     loadConversations,
     loadMore,
-    newChat,
+    getChatId,
     openChat,
     deleteChat,
     renameChat,
@@ -184,5 +182,10 @@ export function useDebugStore() {
     cancelWorkflow: (cid: string) => streamManager.cancelWorkflow(cid, 'debug', currentApplicationId),
     // 文件
     uploadFile,
+    // composer 重置
+    composerResetSignal,
+    resetComposer: () => {
+      composerResetSignal.value++
+    },
   }
 }
diff --git a/ui/src/components/conversation/content/items/form.vue b/ui/src/components/conversation/content/items/form.vue
index 65944120234..14783f55ca6 100644
--- a/ui/src/components/conversation/content/items/form.vue
+++ b/ui/src/components/conversation/content/items/form.vue
@@ -1,11 +1,6 @@
 <template>
   <div class="content-form">
-    <MkDynamicsForm
-      ref="dynamicsFormRef"
-      :view="is_submit"
-      :render-data="form_field_list"
-      v-model="form_data"
-    />
+    <MkDynamicsForm ref="dynamicsFormRef" :view="is_submit" :render-data="form_field_list" v-model="form_data" />
     <el-button :type="is_submit ? 'info' : 'primary'" :disabled="is_submit" @click="submit">
       {{ is_submit ? '已提交' : '提交' }}
     </el-button>
@@ -16,7 +11,8 @@
 import { computed, ref, inject } from 'vue'
 import { MkDynamicsForm } from '@/components/mk-dynamics-form'
 
-const chat = inject<any>('chat')
+// 由 chat-panel 注入的通用「发起对话」函数
+const sendMessage = inject<(opts: any) => void>('sendMessage')
 
 const props = defineProps<{
   content: any
@@ -30,41 +26,25 @@ const form_data = computed({
   get: () => (props.content.is_submit ? props.content.form_data : _form_data.value),
   set: (v) => {
     _form_data.value = v
-  }
+  },
 })
 const dynamicsFormRef = ref()
 
+// 表单重提交是对同一条 chat_record 的续跑（newQuestion=false）：
+// 不新增 question，续跑分片由 chat-panel 聚合回持有本表单的那条 assistant 消息。
 const submit = async () => {
   try {
     await dynamicsFormRef.value?.validate()
     _submit.value = true
-    
-    if (chat?.sendMessage) {
-      // 确保有对话 ID
-      if (!chat.currentChatId?.value && chat?.openChat) {
-        await chat.openChat()
-      }
-      
-      // 传递 position、chat_record_id、chunk_id
-      const position = props.content.position || null
-      const chatRecordId = props.content.chat_record_id || null
-      const chunkId = props.content.id || null
-      
-      // form_data 只包含表单收集到的数据
-      const formData = { ...form_data.value }
-      
-      // 使用 form_content_format 作为消息
-      const message = props.content.form_content_format || '表单已提交'
-      
-      await chat.sendMessage(message, { 
-        re_chat: true, 
-        form_data: formData,
-        position: position,
-        chat_record_id: chatRecordId,
-        chunk_id: chunkId,
-        onScroll: () => chat.scrollToBottom?.()
-      })
-    }
+    sendMessage?.({
+      message: { content: '', type: 'QUESTION' },
+      newQuestion: false,
+      reChat: true,
+      formData: { ...form_data.value },
+      position: props.content.position || null,
+      chatRecordId: props.content.chat_record_id || null,
+      chunkId: props.content.id || null,
+    })
   } catch (e) {
     console.error('Form submit failed:', e)
     _submit.value = false
diff --git a/ui/src/components/conversation/sidebar/index.vue b/ui/src/components/conversation/sidebar/index.vue
index 50278023348..97b66227917 100644
--- a/ui/src/components/conversation/sidebar/index.vue
+++ b/ui/src/components/conversation/sidebar/index.vue
@@ -112,6 +112,8 @@ const renamingId = ref<string | null>(null)
 const renameValue = ref('')
 
 const handleSwitch = async (id: string) => {
+  // 切换会话丢弃当前未发送的暂存文件/输入，避免其 source_id 绑在旧会话上
+  store.resetComposer()
   store.currentChatId.value = id
   await store.switchConversation(id)
   if (props.mode === 'drawer') emit('update:open', false)
@@ -128,8 +130,13 @@ const handleDelete = async (id: string) => {
 }
 
 const handleNew = () => {
-  // 本地草稿：仅生成 chat_id 并清空消息，不请求后端 open（避免产生空会话）。
-  store.newChat()
+  // 已在空白新对话（无消息）则不动：保留当前 chat_id 与暂存文件（幂等，避免连点/上传后再点导致 id 变化）。
+  // 只有从已有会话切回空白时才重置消息并清空暂存文件（旧文件的 source_id 绑在旧会话上）。
+  if (store.messages.value.length > 0) {
+    store.resetComposer()
+    store.currentChatId.value = ''
+    store.resetMsgState()
+  }
   if (props.mode === 'drawer') emit('update:open', false)
 }