diff --git a/config/config.yaml b/config/config.yaml
index c7669909c..5f8a19e28 100644
--- a/config/config.yaml
+++ b/config/config.yaml
@@ -11,30 +11,18 @@ conversation:
   vector_threshold: 0.5
   rerank_threshold: 0.5
   rerank_top_k: 5
-  fallback_strategy: "fixed"
+  fallback_strategy: "model"
   fallback_response: "抱歉，我无法回答这个问题。"
   fallback_prompt: |
-    你是一个专业、友好的AI助手。现在用户提出的问题超出了你的知识库范围，你需要生成一个礼貌且有帮助的回复。
+    你是一个专业、友好的AI助手。请根据你的知识直接回答用户的问题。
 
     ## 回复要求
-    - 诚实承认你无法提供准确答案
-    - 简洁友好，不要过度道歉
-    - 可以提供相关的建议或替代方案
-    - 回复控制在50字以内
+    - 直接回答用户的问题
+    - 简洁清晰，言之有物
+    - 如果涉及实时数据或个人隐私信息，诚实说明无法获取
     - 使用礼貌、专业的语气
 
-    ## Few-shot示例
-
-    用户问题: 今天杭州西湖的游客数量是多少？
-    回复: 抱歉，我无法获取实时的杭州西湖游客数据。您可以通过杭州旅游官网或相关APP查询这一信息。
-
-    用户问题: 张教授的新论文发表了吗？
-    回复: 我没有张教授的最新论文信息。建议您查询学术数据库或直接联系张教授获取最新动态。
-
-    用户问题: 我的银行卡号是多少？
-    回复: 作为AI助手，我无法获取您的个人银行信息。请登录您的银行APP或联系银行客服获取相关信息。
-
-    ## 用户当前的问题是:
+    ## 用户的问题是:
     {{.Query}}
   enable_rewrite: true
   enable_query_expansion: true
@@ -175,28 +163,14 @@ conversation:
     ## 以下是用户给出的文章相关信息：
 
   generate_session_title_prompt: |
-    你是一个专业的会话标题生成助手，你的任务是为用户提问创建简洁、精准且具描述性的标题。
+    根据用户的问题，生成一个简短的会话标题。
 
-    ## 格式要求
-    - 标题长度必须在10个字以内
-    - 标题应准确反映用户问题的核心主题
-    - 使用名词短语结构，避免使用问句
-    - 保持简洁明了，删除非必要词语
-    - 不要使用"关于"、"如何"等冗余词语开头
-    - 直接输出标题文本，不要有任何前缀、解释或标点符号
+    要求：
+    - 5-10个字
+    - 提取核心主题
+    - 只输出标题，无需解释
 
-    ## Few-shot示例
-
-    用户问题: 如何提高英语口语水平？
-    标题: 英语口语提升
-
-    用户问题: 最近上海有什么好玩的展览活动？
-    标题: 上海展览推荐
-
-    用户问题: 苹果手机电池不耐用怎么解决？
-    标题: 苹果电池优化
-
-    ## 用户的问题是：
+    用户问题：
   summary:
     repeat_penalty: 1.0
     temperature: 0.3
diff --git a/frontend/src/api/chat/streame.ts b/frontend/src/api/chat/streame.ts
index 2d3d2ba73..4516f87a5 100644
--- a/frontend/src/api/chat/streame.ts
+++ b/frontend/src/api/chat/streame.ts
@@ -28,7 +28,7 @@ export function useStream() {
   let renderTimer: number | null = null
 
   // 启动流式请求
-  const startStream = async (params: { session_id: any; query: any; knowledge_base_ids?: string[]; agent_enabled?: boolean; web_search_enabled?: boolean; summary_model_id?: string; mcp_service_ids?: string[]; method: string; url: string }) => {
+  const startStream = async (params: { session_id: any; query: any; knowledge_base_ids?: string[]; knowledge_ids?: string[]; agent_enabled?: boolean; web_search_enabled?: boolean; summary_model_id?: string; mcp_service_ids?: string[]; method: string; url: string }) => {
     // 重置状态
     output.value = '';
     error.value = null;
@@ -85,6 +85,10 @@ export function useStream() {
       if (params.knowledge_base_ids !== undefined && params.knowledge_base_ids.length > 0) {
         postBody.knowledge_base_ids = params.knowledge_base_ids;
       }
+      // Include knowledge_ids if provided
+      if (params.knowledge_ids !== undefined && params.knowledge_ids.length > 0) {
+        postBody.knowledge_ids = params.knowledge_ids;
+      }
       // Include web_search_enabled if provided
       if (params.web_search_enabled !== undefined) {
         postBody.web_search_enabled = params.web_search_enabled;
diff --git a/frontend/src/api/knowledge-base/index.ts b/frontend/src/api/knowledge-base/index.ts
index 236a6e1e7..7c5f1cb34 100644
--- a/frontend/src/api/knowledge-base/index.ts
+++ b/frontend/src/api/knowledge-base/index.ts
@@ -230,4 +230,8 @@ export interface FAQImportProgress {
 
 export function getFAQImportProgress(taskId: string) {
   return get(`/api/v1/faq/import/progress/${taskId}`);
-}
\ No newline at end of file
+}
+
+export function searchKnowledge(keyword: string, offset = 0, limit = 20) {
+  return get(`/api/v1/knowledge/search?keyword=${encodeURIComponent(keyword)}&offset=${offset}&limit=${limit}`);
+}
diff --git a/frontend/src/components/Input-field.vue b/frontend/src/components/Input-field.vue
index 89b446a0a..44534ee3a 100644
--- a/frontend/src/components/Input-field.vue
+++ b/frontend/src/components/Input-field.vue
@@ -1,13 +1,15 @@
 <script setup lang="ts">
-import { ref, defineEmits, onMounted, onUnmounted, defineProps, computed, watch, nextTick, h } from "vue";
+import { ref, onMounted, onUnmounted, computed, watch, nextTick, h } from "vue";
 import { useRoute, useRouter } from 'vue-router';
 import { onBeforeRouteUpdate } from 'vue-router';
 import { MessagePlugin } from "tdesign-vue-next";
 import { useSettingsStore } from '@/stores/settings';
 import { useUIStore } from '@/stores/ui';
-import { listKnowledgeBases } from '@/api/knowledge-base';
+import { listKnowledgeBases, searchKnowledge, batchQueryKnowledge } from '@/api/knowledge-base';
 import { stopSession } from '@/api/chat';
 import KnowledgeBaseSelector from './KnowledgeBaseSelector.vue';
+import MentionSelector from './MentionSelector.vue';
+import { getCaretCoordinates } from '@/utils/caret';
 import { listModels, type ModelConfig } from '@/api/model';
 import { getTenantWebSearchConfig } from '@/api/web-search';
 import { getConversationConfig, updateConversationConfig, type ConversationConfig } from '@/api/system';
@@ -24,6 +26,21 @@ const showAgentModeSelector = ref(false);
 const agentModeButtonRef = ref<HTMLElement>();
 const agentModeDropdownStyle = ref<Record<string, string>>({});
 
+// Mention related state
+const showMention = ref(false);
+const mentionQuery = ref("");
+const mentionItems = ref<Array<{ id: string; name: string; type: 'kb' | 'file'; kbType?: 'document' | 'faq'; count?: number; kbName?: string }>>([]);
+const mentionActiveIndex = ref(0);
+const mentionStyle = ref<Record<string, string>>({});
+const textareaRef = ref<any>(null); // Ref to t-textarea component
+const mentionStartPos = ref(0);
+const isComposing = ref(false);
+const isMentionTriggeredByButton = ref(false);
+const mentionHasMore = ref(false);
+const mentionLoading = ref(false);
+const mentionOffset = ref(0);
+const MENTION_PAGE_SIZE = 20;
+
 const props = defineProps({
   isReplying: {
     type: Boolean,
@@ -42,14 +59,49 @@ const props = defineProps({
 const isAgentEnabled = computed(() => settingsStore.isAgentEnabled);
 const isWebSearchEnabled = computed(() => settingsStore.isWebSearchEnabled);
 const selectedKbIds = computed(() => settingsStore.settings.selectedKnowledgeBases || []);
+const selectedFileIds = computed(() => settingsStore.settings.selectedFiles || []);
 const isWebSearchConfigured = ref(false);
 
 // 获取已选择的知识库信息
-const knowledgeBases = ref<Array<{ id: string; name: string }>>([]);
+const knowledgeBases = ref<Array<{ id: string; name: string; type?: 'document' | 'faq'; knowledge_count?: number; chunk_count?: number }>>([]);
+const fileList = ref<Array<{ id: string; name: string }>>([]);
+
 const selectedKbs = computed(() => {
   return knowledgeBases.value.filter(kb => selectedKbIds.value.includes(kb.id));
 });
 
+const selectedFiles = computed(() => {
+  // If we have file details in fileList, use them.
+  // Otherwise we might show ID or Loading...
+  return selectedFileIds.value.map((id: string) => {
+    const found = fileList.value.find(f => f.id === id);
+    return found || { id, name: 'Loading...' };
+  });
+});
+
+  // 合并所有选中项（用于输入框内显示）
+  const allSelectedItems = computed(() => {
+    const kbs = selectedKbs.value.map(kb => ({ 
+      ...kb, 
+      type: 'kb' as const,
+      kbType: kb.type // 保留原始类型用于显示区分
+    }));
+    const files = selectedFiles.value.map((f: { id: string; name: string }) => ({ 
+      ...f, 
+      type: 'file' as const 
+    }));
+    return [...kbs, ...files];
+  });
+
+// 移除选中项
+const removeSelectedItem = (item: { id: string; type: 'kb' | 'file' }) => {
+  if (item.type === 'kb') {
+    settingsStore.removeKnowledgeBase(item.id);
+  } else {
+    settingsStore.removeFile(item.id);
+  }
+};
+
 // 模型相关状态
 const availableModels = ref<ModelConfig[]>([]);
 const selectedModelId = ref<string>('');
@@ -91,6 +143,31 @@ const loadKnowledgeBases = async () => {
   }
 };
 
+const loadFiles = async () => {
+  const ids = selectedFileIds.value;
+  if (ids.length === 0) return;
+  
+  // Filter out files we already have info for
+  const missingIds = ids.filter((id: string) => !fileList.value.find(f => f.id === id));
+  if (missingIds.length === 0) return;
+
+  try {
+    const query = new URLSearchParams();
+    missingIds.forEach((id: string) => query.append('ids', id));
+    const res: any = await batchQueryKnowledge(query.toString());
+    if (res.data) {
+      const newFiles = res.data.map((f: any) => ({ id: f.id, name: f.title || f.file_name }));
+      fileList.value = [...fileList.value, ...newFiles];
+    }
+  } catch (e) {
+    console.error("Failed to load files", e);
+  }
+};
+
+watch(selectedFileIds, () => {
+  loadFiles();
+}, { immediate: true });
+
 const loadWebSearchConfig = async () => {
   try {
     const response: any = await getTenantWebSearchConfig();
@@ -322,8 +399,299 @@ const updateModelDropdownPosition = () => {
   console.log('[Model Dropdown] Applied style:', modelDropdownStyle.value);
 };
 
+// Mention Logic
+let lastMentionQuery = '';
+const loadMentionItems = async (q: string, resetIndex = true, append = false) => {
+  console.log('[Mention] loadMentionItems called with query:', q, 'append:', append);
+  
+  if (!append) {
+    mentionOffset.value = 0;
+  }
+  
+  // Fetch KBs (always show, filter by query) - only on first load
+  let kbItems: any[] = [];
+  if (!append) {
+    const kbs = knowledgeBases.value.filter(kb => 
+      !q || kb.name.toLowerCase().includes(q.toLowerCase())
+    );
+    kbItems = kbs.map(kb => ({ 
+      id: kb.id, 
+      name: kb.name, 
+      type: 'kb' as const, 
+      kbType: kb.type || 'document',
+      count: kb.type === 'faq' ? (kb.chunk_count || 0) : (kb.knowledge_count || 0)
+    }));
+  }
+  
+  // Fetch Files from API
+  let fileItems: any[] = [];
+  mentionLoading.value = true;
+  try {
+    const res: any = await searchKnowledge(q || '', mentionOffset.value, MENTION_PAGE_SIZE);
+    console.log('[Mention] searchKnowledge response:', res);
+    if (res.data && Array.isArray(res.data)) {
+      fileItems = res.data.map((f: any) => ({ 
+        id: f.id, 
+        name: f.title || f.file_name, 
+        type: 'file' as const,
+        kbName: f.knowledge_base_name || ''
+      }));
+    }
+    mentionHasMore.value = res.has_more || false;
+    mentionOffset.value += fileItems.length;
+  } catch (e) {
+    console.error('[Mention] searchKnowledge error:', e);
+    mentionHasMore.value = false;
+  } finally {
+    mentionLoading.value = false;
+  }
+  
+  if (append) {
+    // Append file items to existing list
+    mentionItems.value = [...mentionItems.value, ...fileItems];
+  } else {
+    mentionItems.value = [...kbItems, ...fileItems];
+  }
+  console.log('[Mention] Total items:', mentionItems.value.length, { kbItems: kbItems.length, fileItems: fileItems.length });
+  
+  // Only reset index if query changed or explicitly requested
+  if (resetIndex || q !== lastMentionQuery) {
+    mentionActiveIndex.value = 0;
+  }
+  // Ensure index is within bounds
+  if (mentionActiveIndex.value >= mentionItems.value.length) {
+    mentionActiveIndex.value = Math.max(0, mentionItems.value.length - 1);
+  }
+  lastMentionQuery = q;
+};
+
+const loadMoreMentionItems = () => {
+  if (mentionHasMore.value && !mentionLoading.value) {
+    loadMentionItems(lastMentionQuery, false, true);
+  }
+};
+
+const getTextareaEl = () => {
+  if (!textareaRef.value) return null;
+  // If it's a native element
+  if (textareaRef.value instanceof HTMLTextAreaElement) return textareaRef.value;
+  // If it's a component wrapper
+  const el = textareaRef.value.$el || textareaRef.value;
+  if (!el) return null;
+  if (el.tagName === 'TEXTAREA') return el as HTMLTextAreaElement;
+  return el.querySelector('textarea');
+};
+
+const onInput = (val: string | InputEvent) => {
+  // 如果正在输入法组合中，不处理搜索逻辑，等待 compositionend
+  if (isComposing.value) return;
+
+  // TDesign t-textarea passes the value directly, not an event
+  const inputVal = typeof val === 'string' ? val : query.value;
+  
+  const textarea = getTextareaEl();
+  if (!textarea) {
+    console.warn('[Mention] Could not get textarea element');
+    return;
+  }
+  
+  const cursor = textarea.selectionStart;
+  const textBeforeCursor = inputVal.slice(0, cursor);
+  
+  console.log('[Mention] onInput called', { inputVal, cursor, textBeforeCursor, showMention: showMention.value });
+  
+  if (showMention.value) {
+    // 如果不是按钮触发的，检查 @ 符号
+    if (!isMentionTriggeredByButton.value) {
+      if (!inputVal || inputVal.length <= mentionStartPos.value || inputVal.charAt(mentionStartPos.value) !== '@') {
+        showMention.value = false;
+        return;
+      }
+    }
+
+    // 如果是按钮触发的，mentionStartPos 指向的是光标位置（即虚拟的 @ 位置前），所以实际上不应该往左删
+    // 但如果用户删除了前面的内容导致长度变短，也需要处理
+    if (cursor < mentionStartPos.value) {
+      showMention.value = false;
+      return;
+    }
+    
+    // Get query
+    // 如果是按钮触发，mentionStartPos 是起始位置，不需要 +1 跳过 @
+    const start = isMentionTriggeredByButton.value ? mentionStartPos.value : mentionStartPos.value + 1;
+    const q = inputVal.slice(start, cursor);
+    
+    if (q.includes(' ')) {
+      showMention.value = false;
+      return;
+    }
+    // Only reload if query changed
+    if (q !== mentionQuery.value) {
+      mentionQuery.value = q;
+      loadMentionItems(q, true); // Reset index when query changes
+    }
+  } else {
+    if (textBeforeCursor.endsWith('@')) {
+      console.log('[Mention] @ detected, opening menu');
+      isMentionTriggeredByButton.value = false;
+      mentionStartPos.value = cursor - 1;
+      showMention.value = true;
+      mentionQuery.value = "";
+      
+      const coords = getCaretCoordinates(textarea, cursor);
+      const rect = textarea.getBoundingClientRect();
+      const scrollTop = textarea.scrollTop;
+      const menuHeight = 320; // 预估最大高度
+      
+      let left = rect.left + coords.left;
+      // Prevent menu from going off-screen horizontally
+      if (left + 300 > window.innerWidth) {
+        left = window.innerWidth - 300 - 10;
+      }
+      
+      // 光标相对于视口的实际 top 位置
+      const cursorAbsoluteTop = rect.top + coords.top - scrollTop;
+      const lineHeight = coords.height; // 光标高度
+
+      // Check vertical space below cursor
+      const spaceBelow = window.innerHeight - (cursorAbsoluteTop + lineHeight);
+      
+      if (spaceBelow < menuHeight && cursorAbsoluteTop > menuHeight) {
+         // Show above cursor (using bottom positioning)
+         // bottom distance = viewport height - cursor top position
+         const bottom = window.innerHeight - cursorAbsoluteTop;
+         mentionStyle.value = {
+           left: `${left}px`,
+           bottom: `${bottom}px`,
+           top: 'auto'
+         };
+      } else {
+         // Show below cursor (using top positioning)
+         const top = cursorAbsoluteTop + lineHeight;
+         mentionStyle.value = {
+           left: `${left}px`,
+           top: `${top}px`,
+           bottom: 'auto'
+         };
+      }
+      
+      loadMentionItems("");
+    }
+  }
+};
+
+const onCompositionStart = () => {
+  isComposing.value = true;
+};
+
+const onCompositionEnd = (e: CompositionEvent) => {
+  isComposing.value = false;
+  // 手动触发 onInput 逻辑
+  // 注意：在 compositionend 时，v-model 可能还没更新，或者已经更新但我们需要用最新值
+  // TDesign textarea 可能需要 nextTick
+  nextTick(() => {
+    onInput(query.value);
+  });
+};
+
+const triggerMention = () => {
+  const textarea = getTextareaEl();
+  if (!textarea) return;
+  
+  // 关闭其他选择器
+  showAgentModeSelector.value = false;
+  showModelSelector.value = false;
+
+  textarea.focus();
+  
+  // 直接显示菜单，不插入 @
+  showMention.value = true;
+  isMentionTriggeredByButton.value = true;
+  mentionQuery.value = "";
+  mentionStartPos.value = textarea.selectionStart;
+  
+  const rect = textarea.getBoundingClientRect();
+  const menuHeight = 320;
+  
+  // 判断输入框上方空间
+  const spaceAbove = rect.top;
+  const spaceBelow = window.innerHeight - rect.bottom;
+  
+  // 优先显示在上方，除非上方空间不足且下方空间充足
+  if (spaceAbove > menuHeight || spaceAbove > spaceBelow) {
+    // Show above textarea
+    mentionStyle.value = {
+      left: `${rect.left}px`,
+      bottom: `${window.innerHeight - rect.top + 8}px`, // 8px padding
+      top: 'auto'
+    };
+  } else {
+    // Show below textarea
+    mentionStyle.value = {
+      left: `${rect.left}px`,
+      top: `${rect.bottom + 8}px`,
+      bottom: 'auto'
+    };
+  }
+  
+  loadMentionItems("");
+};
+
+const onMentionSelect = (item: any) => {
+  if (item.type === 'kb') {
+      settingsStore.addKnowledgeBase(item.id);
+  } else if (item.type === 'file') {
+      settingsStore.addFile(item.id);
+      // Add to local cache immediately
+      if (!fileList.value.find(f => f.id === item.id)) {
+        fileList.value.push(item);
+      }
+  }
+  
+  const textarea = getTextareaEl();
+  if (textarea) {
+    // 如果是通过输入 @ 触发的，需要删除 @ 和后面的查询文字
+    if (!isMentionTriggeredByButton.value) {
+      const cursor = textarea.selectionStart;
+      const textBeforeAt = query.value.slice(0, mentionStartPos.value);
+      const textAfterCursor = query.value.slice(cursor);
+      query.value = textBeforeAt + textAfterCursor;
+      
+      nextTick(() => {
+        textarea.selectionStart = textarea.selectionEnd = mentionStartPos.value;
+        textarea.focus();
+      });
+    } else {
+      // 通过按钮触发的，如果用户输入了查询词，需要删除查询词
+      const cursor = textarea.selectionStart;
+      if (cursor > mentionStartPos.value) {
+         const textBeforeStart = query.value.slice(0, mentionStartPos.value);
+         const textAfterCursor = query.value.slice(cursor);
+         query.value = textBeforeStart + textAfterCursor;
+         
+         nextTick(() => {
+           textarea.selectionStart = textarea.selectionEnd = mentionStartPos.value;
+           textarea.focus();
+         });
+      } else {
+         // 直接聚焦
+         textarea.focus();
+      }
+    }
+  }
+  
+  showMention.value = false;
+};
+
+const removeFile = (id: string) => {
+  settingsStore.removeFile(id);
+};
+
 const toggleModelSelector = () => {
-  if (selectedKbIds.value.length === 0) return;
+  // 互斥：关闭其他
+  showMention.value = false;
+  showAgentModeSelector.value = false;
+
   showModelSelector.value = !showModelSelector.value;
   if (showModelSelector.value) {
     if (!availableModels.value.length) {
@@ -351,6 +719,15 @@ const closeAgentModeSelector = () => {
   showAgentModeSelector.value = false;
 };
 
+const closeMentionSelector = (e: MouseEvent) => {
+  const target = e.target as HTMLElement;
+  // 如果点击的是输入框区域，不关闭 Mention 列表（由光标逻辑控制）
+  if (target.closest('.rich-input-container')) {
+    return;
+  }
+  showMention.value = false;
+};
+
 // 窗口事件处理器
 let resizeHandler: (() => void) | null = null;
 let scrollHandler: (() => void) | null = null;
@@ -370,6 +747,7 @@ onMounted(() => {
   // 监听点击外部关闭下拉菜单
   document.addEventListener('click', closeAgentModeSelector);
   document.addEventListener('click', closeModelSelector);
+  document.addEventListener('click', closeMentionSelector);
   
   // 监听窗口大小变化和滚动，重新计算位置
   resizeHandler = () => {
@@ -396,6 +774,7 @@ onMounted(() => {
 onUnmounted(() => {
   document.removeEventListener('click', closeAgentModeSelector);
   document.removeEventListener('click', closeModelSelector);
+  document.removeEventListener('click', closeMentionSelector);
   if (resizeHandler) {
     window.removeEventListener('resize', resizeHandler);
   }
@@ -417,8 +796,8 @@ watch(() => uiStore.showSettingsModal, (visible, prevVisible) => {
   }
 });
 
-watch(selectedKbIds, (ids) => {
-  if (!ids.length) {
+watch([selectedKbIds, selectedFileIds], ([kbIds, fileIds]) => {
+  if (!kbIds.length && !fileIds.length) {
     closeModelSelector();
   }
 }, { deep: true });
@@ -430,10 +809,6 @@ const createSession = (val: string) => {
     MessagePlugin.info(t('input.messages.enterContent'));
     return;
   }
-  if (selectedKbIds.value.length === 0) {
-    MessagePlugin.warning(t('input.messages.selectKnowledge'));
-    return;
-  }
   if (props.isReplying) {
     return MessagePlugin.error(t('input.messages.replying'));
   }
@@ -531,6 +906,10 @@ const toggleAgentModeSelector = () => {
     return;
   }
   
+  // 互斥
+  showMention.value = false;
+  showModelSelector.value = false;
+
   showAgentModeSelector.value = !showAgentModeSelector.value;
   if (showAgentModeSelector.value) {
     // 多次更新位置确保准确
@@ -566,6 +945,44 @@ const clearvalue = () => {
 }
 
 const onKeydown = (val: string, event: { e: { preventDefault(): unknown; keyCode: number; shiftKey: any; ctrlKey: any; }; }) => {
+  if (showMention.value) {
+    if (event.e.keyCode === 38) { // Up
+      event.e.preventDefault();
+      mentionActiveIndex.value = Math.max(0, mentionActiveIndex.value - 1);
+      return;
+    }
+    if (event.e.keyCode === 40) { // Down
+      event.e.preventDefault();
+      mentionActiveIndex.value = Math.min(mentionItems.value.length - 1, mentionActiveIndex.value + 1);
+      return;
+    }
+    if (event.e.keyCode === 13) { // Enter
+      event.e.preventDefault();
+      if (mentionItems.value[mentionActiveIndex.value]) {
+        onMentionSelect(mentionItems.value[mentionActiveIndex.value]);
+      }
+      return;
+    }
+    if (event.e.keyCode === 27) { // Esc
+        showMention.value = false;
+        return;
+    }
+  }
+
+  // 退格键：当输入框为空且有选中项时，删除最后一个选中项
+  if (event.e.keyCode === 8) { // Backspace
+    const textarea = getTextareaEl();
+    if (textarea && textarea.selectionStart === 0 && textarea.selectionEnd === 0 && query.value === '') {
+      const items = allSelectedItems.value;
+      if (items.length > 0) {
+        event.e.preventDefault();
+        const lastItem = items[items.length - 1];
+        removeSelectedItem(lastItem);
+        return;
+      }
+    }
+  }
+
   if ((event.e.keyCode == 13 && event.e.shiftKey) || (event.e.keyCode == 13 && event.e.ctrlKey)) {
     return;
   }
@@ -654,6 +1071,11 @@ const toggleAgentMode = () => {
 }
 
 const toggleWebSearch = () => {
+  // 互斥：虽然不是弹出层，但操作时关闭其他弹出层体验更好
+  showMention.value = false;
+  showModelSelector.value = false;
+  showAgentModeSelector.value = false;
+
   if (!isWebSearchConfigured.value) {
     const messageContent = h('div', { style: 'display: flex; flex-direction: column; gap: 6px; max-width: 280px;' }, [
       h('span', { style: 'color: #333; line-height: 1.5;' }, t('input.messages.webSearchNotConfigured')),
@@ -727,7 +1149,54 @@ onBeforeRouteUpdate((to, from, next) => {
 </script>
 <template>
   <div class="answers-input">
-    <t-textarea v-model="query" :placeholder="$t('input.placeholder')" name="description" :autosize="true" @keydown="onKeydown" />
+    <!-- 富文本输入框容器 -->
+    <div class="rich-input-container">
+      <!-- 选中的知识库和文件标签（显示在输入框内顶部） -->
+      <div v-if="allSelectedItems.length > 0" class="selected-tags-inline">
+        <span 
+          v-for="item in allSelectedItems" 
+          :key="item.id" 
+          class="inline-tag"
+          :class="[
+            item.type === 'kb' ? (item.kbType === 'faq' ? 'faq-tag' : 'kb-tag') : 'file-tag'
+          ]"
+        >
+          <span class="tag-icon">
+            <t-icon v-if="item.type === 'kb'" :name="item.kbType === 'faq' ? 'chat-bubble-help' : 'folder'" />
+            <t-icon v-else name="file" />
+          </span>
+          <span class="tag-name">{{ item.name }}</span>
+          <span class="tag-remove" @click="removeSelectedItem(item)">×</span>
+        </span>
+      </div>
+      
+      <!-- 实际输入框 -->
+      <t-textarea 
+        ref="textareaRef"
+        v-model="query" 
+        :placeholder="allSelectedItems.length > 0 ? $t('input.placeholderWithContext') : $t('input.placeholder')" 
+        name="description" 
+        :autosize="true" 
+        @keydown="onKeydown" 
+        @input="onInput"
+        @compositionstart="onCompositionStart"
+        @compositionend="onCompositionEnd"
+      />
+    </div>
+    
+    <!-- Mention Selector -->
+    <Teleport to="body">
+      <MentionSelector
+        :visible="showMention"
+        :style="mentionStyle"
+        :items="mentionItems"
+        :hasMore="mentionHasMore"
+        :loading="mentionLoading"
+        v-model:activeIndex="mentionActiveIndex"
+        @select="onMentionSelect"
+        @loadMore="loadMoreMentionItems"
+      />
+    </Teleport>
     
     <!-- 控制栏 -->
     <div class="control-bar">
@@ -879,50 +1348,25 @@ onBeforeRouteUpdate((to, from, next) => {
           </div>
         </t-tooltip>
 
-        <!-- @ 知识库选择按钮 -->
-        <div 
-          ref="atButtonRef"
-          class="control-btn kb-btn"
-          :class="{ 'active': selectedKbIds.length > 0 }"
-          @click="toggleKbSelector"
-        >
-          <img :src="getImgSrc('at-icon.svg')" alt="@" class="control-icon" />
-          <span class="kb-btn-text">
-            {{ selectedKbIds.length > 0 ? $t('input.knowledgeBaseWithCount', { count: selectedKbIds.length }) : $t('input.knowledgeBase') }}
-          </span>
-          <svg 
-            width="12" 
-            height="12" 
-            viewBox="0 0 12 12" 
-            fill="currentColor"
-            class="dropdown-arrow"
-            :class="{ 'rotate': showKbSelector }"
-          >
-            <path d="M2.5 4.5L6 8L9.5 4.5H2.5Z"/>
-          </svg>
-        </div>
-
-        <!-- 已选择的知识库标签 -->
-        <div v-if="displayedKbs.length > 0" class="kb-tags">
+        <!-- @ 知识库/文件选择按钮 -->
+        <t-tooltip :content="allSelectedItems.length > 0 ? $t('input.knowledgeBaseWithCount', { count: allSelectedItems.length }) : $t('input.knowledgeBase')">
           <div 
-            v-for="kb in displayedKbs" 
-            :key="kb.id" 
-            class="kb-tag"
+            ref="atButtonRef"
+            class="control-btn kb-btn"
+            :class="{ 'active': allSelectedItems.length > 0 }"
+            @click.stop
+            @mousedown.prevent="triggerMention"
           >
-            <span class="kb-tag-text">{{ kb.name }}</span>
-            <span class="kb-tag-remove" @click.stop="removeKb(kb.id)">×</span>
+            <img :src="getImgSrc('at-icon.svg')" alt="@" class="control-icon" />
+            <span v-if="allSelectedItems.length > 0" class="kb-count">{{ allSelectedItems.length }}</span>
           </div>
-          <div v-if="remainingCount > 0" class="kb-tag more-tag">
-            +{{ remainingCount }}
-          </div>
-        </div>
+        </t-tooltip>
 
         <!-- 模型显示 -->
         <div class="model-display">
           <div
             ref="modelButtonRef"
             class="model-selector-trigger"
-            :class="{ disabled: selectedKbIds.length === 0 }"
             @click.stop="toggleModelSelector"
           >
             <span class="model-selector-name">
@@ -1002,7 +1446,7 @@ onBeforeRouteUpdate((to, from, next) => {
           v-if="!isReplying"
         @click="createSession(query)" 
         class="control-btn send-btn"
-        :class="{ 'disabled': !query.length || selectedKbIds.length === 0 }"
+        :class="{ 'disabled': !query.length }"
       >
         <img src="../assets/img/sending-aircraft.svg" :alt="$t('input.send')" />
         </div>
@@ -1033,37 +1477,146 @@ const getImgSrc = (url: string) => {
   transform: translateX(-400px);
 }
 
+/* 富文本输入框容器 */
+.rich-input-container {
+  position: relative;
+  width: 800px;
+  background: var(--td-bg-color-container, #FFF);
+  border-radius: 12px;
+  border: 1px solid var(--td-component-border, #E7E7E7);
+  box-shadow: 0 6px 6px 0 rgba(0, 0, 0, 0.04), 0 12px 12px -1px rgba(0, 0, 0, 0.08);
+  
+  &:focus-within {
+    border-color: var(--td-brand-color, #07C05F);
+  }
+}
+
+/* 选中的标签（输入框内顶部） */
+.selected-tags-inline {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 6px;
+  padding: 12px 16px 8px;
+  border-bottom: 1px solid var(--td-component-border, #f0f0f0);
+}
+
+.inline-tag {
+  display: inline-flex;
+  align-items: center;
+  gap: 4px;
+  padding: 4px 8px;
+  border-radius: 6px;
+  font-size: 12px;
+  font-weight: 500;
+  cursor: default;
+  transition: all 0.15s;
+  background: var(--td-bg-color-secondarycontainer, #f3f3f3);
+  border: 1px solid transparent;
+  color: var(--td-text-color-primary, #333);
+  
+  /* KB - Document (Greenish tint) */
+  &.kb-tag {
+    background: rgba(16, 185, 129, 0.08);
+    color: #059669;
+    
+    .tag-icon {
+      color: #10b981;
+    }
+  }
+
+  /* KB - FAQ (Blueish tint) */
+  &.faq-tag {
+    background: rgba(0, 82, 217, 0.08);
+    color: #0052d9;
+    
+    .tag-icon {
+      color: #0052d9;
+    }
+  }
+  
+  /* File (Orange tint) */
+  &.file-tag {
+    background: rgba(237, 123, 47, 0.08);
+    color: #e65100;
+    
+    .tag-icon {
+      color: #ed7b2f;
+    }
+  }
+  
+  .tag-icon {
+    font-size: 14px;
+    display: flex;
+    align-items: center;
+  }
+  
+  .tag-name {
+    max-width: 120px;
+    overflow: hidden;
+    text-overflow: ellipsis;
+    white-space: nowrap;
+    color: currentColor;
+  }
+  
+  .tag-remove {
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    width: 14px;
+    height: 14px;
+    margin-left: 2px;
+    border-radius: 50%;
+    font-size: 14px;
+    line-height: 1;
+    cursor: pointer;
+    opacity: 0.5;
+    transition: opacity 0.15s, background 0.15s;
+    color: currentColor;
+    
+    &:hover {
+      opacity: 1;
+      background: rgba(0, 0, 0, 0.1);
+    }
+  }
+}
+
 :deep(.t-textarea__inner) {
   width: 100%;
-  width: 800px;
-  max-height: 250px !important;
-  min-height: 112px !important;
+  max-height: 200px !important;
+  min-height: 120px !important;
   resize: none;
-  color: #000000e6;
+  color: var(--td-text-color-primary, #000000e6);
   font-size: 16px;
   font-weight: 400;
   line-height: 24px;
-  font-family: "PingFang SC";
-  padding: 16px 12px 72px 16px;  /* 增加底部padding为控制栏腾出更多空间（原52px -> 72px） */
-  border-radius: 12px;
-  border: 1px solid #E7E7E7;
+  font-family: var(--td-font-family, "PingFang SC");
+  padding: 12px 16px 56px 16px;
+  border-radius: 0 0 12px 12px;
+  border: none;
   box-sizing: border-box;
-  background: #FFF;
-  box-shadow: 0 6px 6px 0 #0000000a, 0 12px 12px -1px #00000014;
+  background: transparent;
+  box-shadow: none;
 
   &:focus {
-    border: 1px solid #07C05F;
+    border: none;
+    box-shadow: none;
   }
 
   &::placeholder {
-    color: #00000066;
-    font-family: "PingFang SC";
+    color: var(--td-text-color-placeholder, #00000066);
+    font-family: var(--td-font-family, "PingFang SC");
     font-size: 16px;
     font-weight: 400;
     line-height: 24px;
   }
 }
 
+/* 当没有选中标签时，textarea 样式 */
+.rich-input-container:not(:has(.selected-tags-inline)) :deep(.t-textarea__inner) {
+  border-radius: 12px;
+  padding-top: 16px;
+}
+
 /* 控制栏 */
 .control-bar {
   position: absolute;
@@ -1074,12 +1627,12 @@ const getImgSrc = (url: string) => {
   align-items: center;
   justify-content: space-between;
   gap: 8px;
-  flex-wrap: wrap;  /* 允许换行，避免内容过多时挤压 */
-  max-height: 56px;  /* 限制最大高度为两行 */
-  z-index: 10;  /* 提高z-index，确保在textarea滚动内容之上 */
-  background: linear-gradient(to bottom, rgba(255, 255, 255, 0.6) 0%, rgba(255, 255, 255, 0.95) 40%, rgba(255, 255, 255, 1) 60%);  /* 更强的渐变背景，从半透明逐渐变为完全不透明 */
-  pointer-events: auto;  /* 确保可以点击 */
-  padding-top: 8px;  /* 增加上边距，给渐变更多空间 */
+  flex-wrap: wrap;
+  max-height: 56px;
+  z-index: 10;
+  background: linear-gradient(to bottom, rgba(255, 255, 255, 0) 0%, var(--td-bg-color-container, #fff) 40%, var(--td-bg-color-container, #fff) 100%);
+  pointer-events: auto;
+  padding-top: 8px;
 }
 
 .control-left {
@@ -1087,9 +1640,8 @@ const getImgSrc = (url: string) => {
   align-items: center;
   gap: 8px;
   flex: 1;
-  overflow: hidden;
-  flex-wrap: wrap;  /* 允许内部元素换行 */
-  min-width: 0;  /* 允许缩小 */
+  flex-wrap: wrap;
+  min-width: 0;
 }
 
 .control-btn {
@@ -1099,14 +1651,14 @@ const getImgSrc = (url: string) => {
   gap: 4px;
   padding: 6px 10px;
   border-radius: 6px;
-  background: #f5f5f5;
+  background: var(--td-bg-color-secondarycontainer, #f5f5f5);
   cursor: pointer;
   transition: background 0.12s;
   user-select: none;
   flex-shrink: 0;
 
   &:hover {
-    background: #e6e6e6;
+    background: var(--td-bg-color-secondarycontainer-hover, #e6e6e6);
   }
 
   &.disabled {
@@ -1114,7 +1666,7 @@ const getImgSrc = (url: string) => {
     cursor: not-allowed;
     
     &:hover {
-      background: #f5f5f5;
+      background: var(--td-bg-color-secondarycontainer, #f5f5f5);
     }
   }
 }
@@ -1154,20 +1706,20 @@ const getImgSrc = (url: string) => {
   }
   
   &:not(.agent-active) {
-    background: rgba(255, 255, 255, 0.8);
-    border-color: #e0e0e0;
+    background: var(--td-bg-color-container, #fff);
+    border-color: var(--td-component-border, #e0e0e0);
     
     .agent-mode-text {
-      color: #666;
+      color: var(--td-text-color-secondary, #666);
     }
     
     .normal-mode-icon {
-      color: #666;
+      color: var(--td-text-color-secondary, #666);
     }
     
     &:hover {
-      background: rgba(255, 255, 255, 1);
-      border-color: #b0b0b0;
+      background: var(--td-bg-color-container-hover, #fff);
+      border-color: var(--td-component-stroke, #b0b0b0);
     }
   }
 }
@@ -1180,7 +1732,7 @@ const getImgSrc = (url: string) => {
 
 .agent-mode-text {
   font-size: 13px;
-  color: #666;
+  color: var(--td-text-color-secondary, #666);
   font-weight: 500;
   white-space: nowrap;
   margin: 0 4px;
@@ -1195,6 +1747,7 @@ const getImgSrc = (url: string) => {
   height: 28px;
   padding: 0 10px;
   min-width: auto;
+  position: relative;
   
   &.active {
     background: rgba(16, 185, 129, 0.1);
@@ -1206,9 +1759,26 @@ const getImgSrc = (url: string) => {
   }
 }
 
+.kb-count {
+  position: absolute;
+  top: -4px;
+  right: -4px;
+  min-width: 16px;
+  height: 16px;
+  padding: 0 4px;
+  background: #07C05F;
+  color: white;
+  font-size: 10px;
+  font-weight: 600;
+  border-radius: 8px;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+}
+
 .kb-btn-text {
   font-size: 13px;
-  color: #666;
+  color: var(--td-text-color-secondary, #666);
   font-weight: 500;
   white-space: nowrap;
 }
@@ -1240,14 +1810,14 @@ const getImgSrc = (url: string) => {
   
   &:not(.active) {
     .websearch-icon {
-      color: #666;
+      color: var(--td-text-color-secondary, #666);
     }
     
     &:hover {
-      background: #f0f0f0;
+      background: var(--td-bg-color-secondarycontainer-hover, #f0f0f0);
       
       .websearch-icon {
-        color: #333;
+        color: var(--td-text-color-primary, #333);
       }
     }
   }
@@ -1259,7 +1829,7 @@ const getImgSrc = (url: string) => {
   gap: 4px;
   max-width: 220px;
   font-size: 12px;
-  color: #666;
+  color: var(--td-text-color-secondary, #666);
 }
 
 :global(.websearch-tooltip-disabled a) {
@@ -1288,65 +1858,6 @@ const getImgSrc = (url: string) => {
   }
 }
 
-.kb-tags {
-  display: flex;
-  align-items: center;
-  gap: 6px;
-  flex: 1;
-  overflow-x: auto;
-  scrollbar-width: none;
-
-  &::-webkit-scrollbar {
-    display: none;
-  }
-}
-
-.kb-tag {
-  display: flex;
-  align-items: center;
-  gap: 4px;
-  padding: 4px 8px;
-  background: rgba(16, 185, 129, 0.1);
-  border: 1px solid rgba(16, 185, 129, 0.3);
-  border-radius: 4px;
-  font-size: 12px;
-  color: #10b981;
-  white-space: nowrap;
-  transition: background 0.12s;
-  
-  &:hover {
-    background: rgba(16, 185, 129, 0.15);
-  }
-}
-
-.kb-tag-text {
-  max-width: 100px;
-  overflow: hidden;
-  text-overflow: ellipsis;
-}
-
-.kb-tag-remove {
-  cursor: pointer;
-  font-weight: bold;
-  font-size: 16px;
-  line-height: 1;
-  opacity: 0.7;
-  
-  &:hover {
-    opacity: 1;
-  }
-}
-
-.more-tag {
-  background: rgba(0, 0, 0, 0.05);
-  border-color: rgba(0, 0, 0, 0.1);
-  color: #666;
-  
-  &:hover {
-    background: rgba(0, 0, 0, 0.08);
-  }
-}
-
 .control-right {
   display: flex;
   align-items: center;
@@ -1412,7 +1923,7 @@ const getImgSrc = (url: string) => {
 .model-display {
   display: flex;
   align-items: center;
-  margin-left: auto;  /* 推到最右边，但仍在 control-left 内 */
+  margin-left: auto;
   flex-shrink: 0;
 }
 
@@ -1482,10 +1993,10 @@ const getImgSrc = (url: string) => {
 .model-selector-dropdown {
   position: fixed !important;
   z-index: 9999;
-  background: #fff;
+  background: var(--td-bg-color-container, #fff);
   border-radius: 10px;
-  box-shadow: 0 6px 28px rgba(15, 23, 42, 0.08);
-  border: 1px solid #e7e9eb;
+  box-shadow: var(--td-shadow-2, 0 6px 28px rgba(15, 23, 42, 0.08));
+  border: 1px solid var(--td-component-border, #e7e9eb);
   overflow: hidden;
   display: flex;
   flex-direction: column;
@@ -1499,11 +2010,11 @@ const getImgSrc = (url: string) => {
   align-items: center;
   justify-content: space-between;
   padding: 8px 10px;
-  border-bottom: 1px solid #f2f4f5;
-  background: #fafcfc;
+  border-bottom: 1px solid var(--td-component-border, #f2f4f5);
+  background: var(--td-bg-color-secondarycontainer, #fafcfc);
   font-size: 12px;
   font-weight: 600;
-  color: #222;
+  color: var(--td-text-color-primary, #222);
 }
 
 .model-selector-content {
@@ -1521,9 +2032,9 @@ const getImgSrc = (url: string) => {
   gap: 4px;
   padding: 3px 8px;
   border-radius: 6px;
-  border: 1px solid #e1e5e6;
-  background: #fff;
-  color: #52575a;
+  border: 1px solid var(--td-component-border, #e1e5e6);
+  background: var(--td-bg-color-container, #fff);
+  color: var(--td-text-color-secondary, #52575a);
   font-size: 11px;
   font-weight: 500;
   cursor: pointer;
@@ -1553,11 +2064,11 @@ const getImgSrc = (url: string) => {
   }
   
   &:hover {
-    background: #f6f8f7;
+    background: var(--td-bg-color-container-hover, #f6f8f7);
   }
   
   &.selected {
-    background: #eefdf5;
+    background: var(--td-brand-color-light, #eefdf5);
     
     .model-option-name {
       color: #10b981;
@@ -1566,7 +2077,7 @@ const getImgSrc = (url: string) => {
   }
   
   &.empty {
-    color: #9aa0a6;
+    color: var(--td-text-color-disabled, #9aa0a6);
     cursor: default;
     text-align: center;
     padding: 20px 8px;
@@ -1586,7 +2097,7 @@ const getImgSrc = (url: string) => {
 
 .model-option-name {
   font-size: 12px;
-  color: #222;
+  color: var(--td-text-color-primary, #222);
   flex: 1;
   overflow: hidden;
   text-overflow: ellipsis;
@@ -1596,7 +2107,7 @@ const getImgSrc = (url: string) => {
 
 .model-option-desc {
   font-size: 11px;
-  color: #8b9196;
+  color: var(--td-text-color-secondary, #8b9196);
   overflow: hidden;
   text-overflow: ellipsis;
   white-space: nowrap;
@@ -1635,10 +2146,10 @@ const getImgSrc = (url: string) => {
 .agent-mode-selector-dropdown {
   position: fixed !important;
   z-index: 9999;
-  background: #fff;
+  background: var(--td-bg-color-container, #fff);
   border-radius: 10px;
-  box-shadow: 0 6px 28px rgba(15, 23, 42, 0.08);
-  border: 1px solid #e7e9eb;
+  box-shadow: var(--td-shadow-2, 0 6px 28px rgba(15, 23, 42, 0.08));
+  border: 1px solid var(--td-component-border, #e7e9eb);
   overflow: hidden;
   padding: 6px 8px;
   min-width: 200px;
@@ -1661,7 +2172,7 @@ const getImgSrc = (url: string) => {
   margin: 4px 6px;
   
   &:hover:not(.disabled) {
-    background: #f6f8f7;
+    background: var(--td-bg-color-container-hover, #f6f8f7);
   }
   
   &.disabled {
@@ -1674,7 +2185,7 @@ const getImgSrc = (url: string) => {
   }
   
   &.selected {
-    background: #eefdf5;
+    background: var(--td-brand-color-light, #eefdf5);
     
     .agent-mode-option-name {
       color: #10b981;
@@ -1694,14 +2205,14 @@ const getImgSrc = (url: string) => {
 .agent-mode-option-name {
   font-size: 12px;
   font-weight: 600;
-  color: #222;
+  color: var(--td-text-color-primary, #222);
   line-height: 1.4;
   transition: color 0.12s;
 }
 
 .agent-mode-option-desc {
   font-size: 11px;
-  color: #8b9196;
+  color: var(--td-text-color-secondary, #8b9196);
   line-height: 1.3;
 }
 
@@ -1726,9 +2237,9 @@ const getImgSrc = (url: string) => {
 
 .agent-mode-footer {
   padding: 6px 10px;
-  border-top: 1px solid #f2f4f5;
+  border-top: 1px solid var(--td-component-border, #f2f4f5);
   margin-top: 2px;
-  background: #fafcfc;
+  background: var(--td-bg-color-secondarycontainer, #fafcfc);
 }
 
 .agent-mode-link {
diff --git a/frontend/src/components/MentionSelector.vue b/frontend/src/components/MentionSelector.vue
new file mode 100644
index 000000000..84e6fba76
--- /dev/null
+++ b/frontend/src/components/MentionSelector.vue
@@ -0,0 +1,243 @@
+<template>
+  <div v-if="visible" class="mention-menu" :style="style" ref="menuRef" @click.stop @scroll="onScroll">
+    <!-- Knowledge Bases Group -->
+    <div v-if="kbItems.length > 0" class="mention-group">
+      <div class="mention-group-header">{{ $t('common.knowledgeBase') }}</div>
+      <div 
+        v-for="(item, index) in kbItems" 
+        :key="item.id"
+        class="mention-item"
+        :class="{ active: index === activeIndex }"
+        @click="$emit('select', item)"
+        @mouseenter="$emit('update:activeIndex', index)"
+      >
+        <div class="icon" :class="item.kbType === 'faq' ? 'faq-icon' : 'kb-icon'">
+          <t-icon :name="item.kbType === 'faq' ? 'chat-bubble-help' : 'folder'" />
+        </div>
+        <span class="name">{{ item.name }}</span>
+        <span class="count">({{ item.count || 0 }})</span>
+      </div>
+    </div>
+    
+    <!-- Files Group -->
+    <div v-if="fileItems.length > 0" class="mention-group">
+      <div class="mention-group-header">{{ $t('common.file') }}</div>
+      <div 
+        v-for="(item, index) in fileItems" 
+        :key="item.id"
+        class="mention-item"
+        :class="{ active: (kbItems.length + index) === activeIndex }"
+        @click="$emit('select', item)"
+        @mouseenter="$emit('update:activeIndex', kbItems.length + index)"
+      >
+        <div class="icon file-icon">
+          <t-icon name="file" />
+        </div>
+        <span class="name">{{ item.name }}</span>
+        <span v-if="item.kbName" class="kb-name">{{ item.kbName }}</span>
+      </div>
+      <!-- Loading indicator -->
+      <div v-if="loading" class="loading-more">
+        <t-loading size="small" />
+      </div>
+    </div>
+    
+    <div v-if="items.length === 0 && !loading" class="empty">
+      {{ $t('common.noResult') }}
+    </div>
+  </div>
+</template>
+
+<script setup lang="ts">
+import { computed, watch, ref, nextTick } from 'vue';
+
+const props = defineProps<{
+  visible: boolean;
+  style: any;
+  items: Array<{ id: string; name: string; type: 'kb' | 'file'; kbType?: 'document' | 'faq'; count?: number; kbName?: string }>;
+  activeIndex: number;
+  hasMore?: boolean;
+  loading?: boolean;
+}>();
+
+const emit = defineEmits(['select', 'update:activeIndex', 'loadMore']);
+
+const menuRef = ref<HTMLElement | null>(null);
+
+const kbItems = computed(() => props.items.filter(item => item.type === 'kb'));
+const fileItems = computed(() => props.items.filter(item => item.type === 'file'));
+
+const onScroll = (e: Event) => {
+  const target = e.target as HTMLElement;
+  const { scrollTop, scrollHeight, clientHeight } = target;
+  // Load more when scrolled to bottom (with 50px threshold)
+  if (scrollHeight - scrollTop - clientHeight < 50 && props.hasMore && !props.loading) {
+    emit('loadMore');
+  }
+};
+
+watch(() => props.activeIndex, (newIndex) => {
+  scrollToItem(newIndex);
+});
+
+watch(() => props.visible, (newVisible) => {
+  if (newVisible) {
+    nextTick(() => {
+      if (menuRef.value) menuRef.value.scrollTop = 0;
+      scrollToItem(props.activeIndex);
+    });
+  }
+});
+
+const scrollToItem = (index: number) => {
+  nextTick(() => {
+    if (!menuRef.value) return;
+    
+    const items = menuRef.value.querySelectorAll('.mention-item');
+    if (!items || items.length <= index) return;
+    
+    const activeItem = items[index] as HTMLElement;
+    const menu = menuRef.value;
+    
+    if (activeItem) {
+      const menuRect = menu.getBoundingClientRect();
+      const itemRect = activeItem.getBoundingClientRect();
+      
+      // 检查是否在上方被遮挡
+      if (itemRect.top < menuRect.top) {
+        menu.scrollTop -= (menuRect.top - itemRect.top);
+      }
+      // 检查是否在下方被遮挡
+      else if (itemRect.bottom > menuRect.bottom) {
+        menu.scrollTop += (itemRect.bottom - menuRect.bottom);
+      }
+    }
+  });
+};
+</script>
+
+<style scoped>
+.mention-menu {
+  position: fixed;
+  z-index: 10000;
+  background: var(--td-bg-color-container, #fff);
+  border: 1px solid var(--td-component-border, #e7e9eb);
+  border-radius: var(--td-radius-medium, 6px);
+  box-shadow: var(--td-shadow-2, 0 3px 14px 2px rgba(0, 0, 0, 0.05));
+  width: 300px;
+  max-height: 360px;
+  overflow-y: auto;
+  display: flex;
+  flex-direction: column;
+  padding: 4px 0;
+}
+
+.mention-group {
+  padding: 4px 0;
+}
+
+.mention-group:not(:last-child) {
+  border-bottom: 1px solid var(--td-component-border, #f0f0f0);
+}
+
+.mention-group-header {
+  padding: 8px 12px 4px;
+  font-size: var(--td-font-size-mark-small, 12px);
+  font-weight: 600;
+  color: var(--td-text-color-secondary, #999);
+}
+
+.mention-item {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  padding: 8px 12px;
+  margin: 0 4px;
+  cursor: pointer;
+  border-radius: var(--td-radius-default, 3px);
+  color: var(--td-text-color-primary, #333);
+  font-size: var(--td-font-size-body-medium, 14px);
+  font-family: var(--td-font-family, "PingFang SC");
+  transition: background 0.2s cubic-bezier(0.38, 0, 0.24, 1);
+}
+
+.mention-item:hover {
+  background: var(--td-bg-color-container-hover, #f3f3f3);
+}
+
+.mention-item.active {
+  background: var(--td-brand-color-light, #e9f8ec);
+  color: var(--td-brand-color, #07c05f);
+}
+
+.icon {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  width: 20px;
+  height: 20px;
+  border-radius: var(--td-radius-small, 2px);
+  flex-shrink: 0;
+  /* background: var(--td-bg-color-secondarycontainer, #f3f3f3); */
+}
+
+/* Document KB - Greenish */
+.kb-icon {
+  background: rgba(16, 185, 129, 0.1);
+  color: #10b981;
+}
+
+/* FAQ KB - Blueish */
+.faq-icon {
+  background: rgba(0, 82, 217, 0.1);
+  color: #0052d9;
+}
+
+/* File - Orange */
+.file-icon {
+  background: rgba(237, 123, 47, 0.1);
+  color: #ed7b2f;
+}
+
+.mention-item.active .icon {
+  /* Active state keeps the colored icon but maybe adjusts background or just inherits */
+  background: transparent;
+  color: inherit;
+}
+
+.name {
+  flex: 1;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.count {
+  flex-shrink: 0;
+  font-size: var(--td-font-size-mark-small, 12px);
+  color: var(--td-text-color-secondary, #999);
+}
+
+.kb-name {
+  flex-shrink: 0;
+  max-width: 80px;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+  font-size: var(--td-font-size-mark-small, 12px);
+  color: var(--td-text-color-secondary, #999);
+}
+
+.empty {
+  padding: 24px 12px;
+  text-align: center;
+  color: var(--td-text-color-placeholder, #999);
+  font-size: var(--td-font-size-body-medium, 14px);
+}
+
+.loading-more {
+  display: flex;
+  justify-content: center;
+  padding: 8px 12px;
+}
+</style>
diff --git a/frontend/src/i18n/locales/en-US.ts b/frontend/src/i18n/locales/en-US.ts
index 20a7cf902..5332e15d3 100644
--- a/frontend/src/i18n/locales/en-US.ts
+++ b/frontend/src/i18n/locales/en-US.ts
@@ -638,6 +638,9 @@ export default {
     confirmDelete: 'Confirm Delete',
     deleteSuccess: 'Deleted successfully',
     deleteFailed: 'Delete failed',
+    file: 'File',
+    knowledgeBase: 'Knowledge Base',
+    noResult: 'No results',
   },
   file: {
     upload: 'Upload File',
@@ -746,6 +749,7 @@ export default {
   input: {
     addModel: 'Add Model',
     placeholder: 'Ask questions based on the knowledge base',
+    placeholderWithContext: 'Enter your question, will answer based on selected knowledge bases/files above',
     agentMode: 'Agent Mode',
     normalMode: 'Normal Mode',
     normalModeDesc: 'Knowledge base RAG Q&A',
diff --git a/frontend/src/i18n/locales/ru-RU.ts b/frontend/src/i18n/locales/ru-RU.ts
index 171ba1e37..c478f53c2 100644
--- a/frontend/src/i18n/locales/ru-RU.ts
+++ b/frontend/src/i18n/locales/ru-RU.ts
@@ -639,6 +639,9 @@ export default {
     confirmDelete: 'Подтвердить удаление',
     deleteSuccess: 'Успешно удалено',
     deleteFailed: 'Ошибка удаления',
+    file: 'Файл',
+    knowledgeBase: 'База знаний',
+    noResult: 'Нет результатов',
   },
   file: {
     upload: 'Загрузить файл',
@@ -1669,6 +1672,7 @@ export default {
   input: {
     addModel: 'Добавить модель',
     placeholder: 'Задайте вопрос на основе базы знаний',
+    placeholderWithContext: 'Введите вопрос, ответ будет основан на выбранных выше базах знаний/файлах',
     agentMode: 'Agent режим',
     normalMode: 'Обычный режим',
     normalModeDesc: 'RAG-вопросы и ответы по базе знаний',
diff --git a/frontend/src/i18n/locales/zh-CN.ts b/frontend/src/i18n/locales/zh-CN.ts
index 2b574291f..633d881a2 100644
--- a/frontend/src/i18n/locales/zh-CN.ts
+++ b/frontend/src/i18n/locales/zh-CN.ts
@@ -731,6 +731,9 @@ export default {
     confirmDelete: "确认删除",
     deleteSuccess: "删除成功",
     deleteFailed: "删除失败",
+    file: "文件",
+    knowledgeBase: "知识库",
+    noResult: "无结果",
   },
   file: {
     upload: "上传文件",
@@ -1150,6 +1153,9 @@ export default {
     messages: {
       deleted: "已删除",
       deleteFailed: "删除失败",
+    file: "文件",
+    knowledgeBase: "知识库",
+    noResult: "无结果",
     },
     features: {
       knowledgeGraph: "已启用知识图谱",
@@ -1422,6 +1428,7 @@ export default {
   input: {
     addModel: "添加模型",
     placeholder: "基于知识库提问",
+    placeholderWithContext: "输入问题，将基于上方选中的知识库/文件回答",
     agentMode: "Agent 模式",
     normalMode: "普通模式",
     normalModeDesc: "基于知识库的 RAG 问答",
diff --git a/frontend/src/stores/settings.ts b/frontend/src/stores/settings.ts
index 52c945924..4e2b1e97e 100644
--- a/frontend/src/stores/settings.ts
+++ b/frontend/src/stores/settings.ts
@@ -8,6 +8,7 @@ interface Settings {
   isAgentEnabled: boolean;
   agentConfig: AgentConfig;
   selectedKnowledgeBases: string[];  // 当前选中的知识库ID列表
+  selectedFiles: string[]; // 当前选中的文件ID列表
   modelConfig: ModelConfig;  // 模型配置
   ollamaConfig: OllamaConfig;  // Ollama配置
   webSearchEnabled: boolean;  // 网络搜索是否启用
@@ -71,6 +72,7 @@ const defaultSettings: Settings = {
     use_custom_system_prompt: false
   },
   selectedKnowledgeBases: [],  // 默认为空数组
+  selectedFiles: [], // 默认为空数组
   modelConfig: {
     chatModels: [],
     embeddingModels: [],
@@ -273,5 +275,30 @@ export const useSettingsStore = defineStore("settings", {
       this.settings.webSearchEnabled = enabled;
       localStorage.setItem("WeKnora_settings", JSON.stringify(this.settings));
     },
+
+    // File selection actions
+    addFile(fileId: string) {
+      if (!this.settings.selectedFiles) this.settings.selectedFiles = [];
+      if (!this.settings.selectedFiles.includes(fileId)) {
+        this.settings.selectedFiles.push(fileId);
+        localStorage.setItem("WeKnora_settings", JSON.stringify(this.settings));
+      }
+    },
+
+    removeFile(fileId: string) {
+      if (!this.settings.selectedFiles) return;
+      this.settings.selectedFiles = this.settings.selectedFiles.filter((id: string) => id !== fileId);
+      localStorage.setItem("WeKnora_settings", JSON.stringify(this.settings));
+    },
+
+    clearFiles() {
+      this.settings.selectedFiles = [];
+      localStorage.setItem("WeKnora_settings", JSON.stringify(this.settings));
+    },
+    
+    getSelectedFiles(): string[] {
+      return this.settings.selectedFiles || [];
+    },
   },
-}); 
\ No newline at end of file
+});
+ 
\ No newline at end of file
diff --git a/frontend/src/utils/caret.ts b/frontend/src/utils/caret.ts
new file mode 100644
index 000000000..512981f1c
--- /dev/null
+++ b/frontend/src/utils/caret.ts
@@ -0,0 +1,58 @@
+export interface CaretCoordinates {
+  top: number;
+  left: number;
+  height: number;
+}
+
+export function getCaretCoordinates(element: HTMLTextAreaElement, position: number): CaretCoordinates {
+  const div = document.createElement('div');
+  const style = window.getComputedStyle(element);
+  
+  // Copy styles
+  const properties = [
+    'direction', 'boxSizing', 'width', 'height', 'overflowX', 'overflowY',
+    'borderTopWidth', 'borderRightWidth', 'borderBottomWidth', 'borderLeftWidth', 'borderStyle',
+    'paddingTop', 'paddingRight', 'paddingBottom', 'paddingLeft',
+    'fontStyle', 'fontVariant', 'fontWeight', 'fontStretch', 'fontSize', 'fontSizeAdjust', 'lineHeight', 'fontFamily',
+    'textAlign', 'textTransform', 'textIndent', 'textDecoration', 'letterSpacing', 'wordSpacing',
+    'tabSize', 'MozTabSize'
+  ];
+
+  properties.forEach(prop => {
+    // @ts-ignore
+    div.style[prop] = style[prop];
+  });
+
+  div.style.position = 'absolute';
+  div.style.visibility = 'hidden';
+  div.style.whiteSpace = 'pre-wrap';
+  div.style.wordWrap = 'break-word';
+  div.style.top = '0';
+  div.style.left = '0';
+
+  // We append a special character to the end of the text to handle the case where the caret is at the end
+  const textContent = element.value.substring(0, position);
+  div.textContent = textContent;
+  
+  const span = document.createElement('span');
+  // Use a zero-width space to simulate the caret position without adding visible width, 
+  // but if it's at the end of a line, we might need something else. 
+  // Standard trick is using a pipe or similar and measuring it.
+  span.textContent = '|'; 
+  div.appendChild(span);
+  
+  document.body.appendChild(div);
+  
+  const spanRect = span.getBoundingClientRect();
+  const divRect = div.getBoundingClientRect();
+  
+  const coordinates = {
+    top: span.offsetTop + parseInt(style.borderTopWidth),
+    left: span.offsetLeft + parseInt(style.borderLeftWidth),
+    height: parseInt(style.lineHeight) || spanRect.height
+  };
+  
+  document.body.removeChild(div);
+  
+  return coordinates;
+}
diff --git a/frontend/src/views/chat/components/AgentStreamDisplay.vue b/frontend/src/views/chat/components/AgentStreamDisplay.vue
index 51b427d02..787d24c3d 100644
--- a/frontend/src/views/chat/components/AgentStreamDisplay.vue
+++ b/frontend/src/views/chat/components/AgentStreamDisplay.vue
@@ -1074,9 +1074,28 @@ const renderMarkdown = (content: any): string => {
   if (!content) return '';
   
   // Ensure content is a string
-  const contentStr = typeof content === 'string' ? content : String(content || '');
+  let contentStr = typeof content === 'string' ? content : String(content || '');
   if (!contentStr.trim()) return '';
   
+  // Handle streaming image syntax to prevent flickering
+  // Check if the content ends with an incomplete image markdown syntax like `![...` or `![...](...`
+  // This prevents the text from being rendered as plain text first and then jumping to an image
+  const lastImgStart = contentStr.lastIndexOf('![');
+  if (lastImgStart !== -1) {
+    // Only check the last occurrence to see if it's incomplete
+    // We check if the tail (from the last ![) contains a matching closing parenthesis )
+    // This is a heuristic: if the last ![ doesn't have a corresponding ), it's likely incomplete
+    const potentialImgTag = contentStr.slice(lastImgStart);
+    const hasClosingParen = potentialImgTag.includes(')');
+    const hasClosingBracket = potentialImgTag.includes(']');
+    
+    // If we have ![ but missing ] or ), it's incomplete
+    // Note: This is a simple check. It might false positive on `![text] (note)` but that's rare in this context
+    if (!hasClosingBracket || !hasClosingParen) {
+       contentStr = contentStr.slice(0, lastImgStart);
+    }
+  }
+
   try {
     // Preprocess custom citation tags into safe HTML the sanitizer will allow
     // Supported formats:
diff --git a/frontend/src/views/chat/index.vue b/frontend/src/views/chat/index.vue
index 399aeaa86..2e2a55d78 100644
--- a/frontend/src/views/chat/index.vue
+++ b/frontend/src/views/chat/index.vue
@@ -311,18 +311,9 @@ const sendMsg = async (value, modelId = '') => {
     
     // Get knowledge_base_ids from settings store (selected by user via KnowledgeBaseSelector)
     const kbIds = useSettingsStoreInstance.settings.selectedKnowledgeBases || [];
+    const knowledgeIds = useSettingsStoreInstance.settings.selectedFiles || [];
     
-    // Validate knowledge_base_ids before sending (only when agent mode is enabled)
-    if (agentEnabled && kbIds.length === 0) {
-        MessagePlugin.warning(t('chat.selectKnowledgeBaseWarning'));
-        isReplying.value = false;
-        loading.value = false;
-        // 清空当前 assistant message ID
-        currentAssistantMessageId.value = '';
-        // Remove the user message that was just added
-        messagesList.pop();
-        return;
-    }
+
     
     // Use agent-chat endpoint when agent is enabled, otherwise use knowledge-chat
     const endpoint = agentEnabled ? '/api/v1/agent-chat' : '/api/v1/knowledge-chat';
@@ -333,6 +324,7 @@ const sendMsg = async (value, modelId = '') => {
     await startStream({ 
         session_id: session_id.value, 
         knowledge_base_ids: kbIds,
+        knowledge_ids: knowledgeIds,
         agent_enabled: agentEnabled,
         web_search_enabled: webSearchEnabled,
         summary_model_id: modelId,
diff --git a/frontend/src/views/creatChat/creatChat.vue b/frontend/src/views/creatChat/creatChat.vue
index 60c4f2719..e3a1f546a 100644
--- a/frontend/src/views/creatChat/creatChat.vue
+++ b/frontend/src/views/creatChat/creatChat.vue
@@ -44,12 +44,8 @@ const sendMsg = (value: string) => {
 }
 
 async function createNewSession(value: string) {
-    const selectedKbs = settingsStore.settings.selectedKnowledgeBases;
-    
-    if (!selectedKbs || selectedKbs.length === 0) {
-        MessagePlugin.warning(t('createChat.messages.selectKnowledgeBase'));
-        return;
-    }
+    const selectedKbs = settingsStore.settings.selectedKnowledgeBases || [];
+    const selectedFiles = settingsStore.settings.selectedFiles || [];
 
     // 构建 session 数据，包含 Agent 配置
     const sessionData: any = {};
@@ -60,6 +56,7 @@ async function createNewSession(value: string) {
         max_iterations: settingsStore.agentConfig.maxIterations,
         temperature: settingsStore.agentConfig.temperature,
         knowledge_bases: selectedKbs,  // 所有选中的知识库
+        knowledge_ids: selectedFiles,  // 所有选中的普通知识/文件
         allowed_tools: settingsStore.agentConfig.allowedTools
     };
 
diff --git a/internal/agent/engine.go b/internal/agent/engine.go
index e0364ade1..a13eec397 100644
--- a/internal/agent/engine.go
+++ b/internal/agent/engine.go
@@ -29,6 +29,7 @@ type AgentEngine struct {
 	chatModel            chat.Chat
 	eventBus             *event.EventBus
 	knowledgeBasesInfo   []*KnowledgeBaseInfo      // Detailed knowledge base information for prompt
+	selectedDocs         []*SelectedDocumentInfo   // User-selected documents (via @ mention)
 	contextManager       interfaces.ContextManager // Context manager for writing agent conversation to LLM context
 	sessionID            string                    // Session ID for context management
 	systemPromptTemplate string                    // System prompt template (optional, uses default if empty)
@@ -50,6 +51,7 @@ func NewAgentEngine(
 	toolRegistry *tools.ToolRegistry,
 	eventBus *event.EventBus,
 	knowledgeBasesInfo []*KnowledgeBaseInfo,
+	selectedDocs []*SelectedDocumentInfo,
 	contextManager interfaces.ContextManager,
 	sessionID string,
 	systemPromptTemplate string,
@@ -63,6 +65,7 @@ func NewAgentEngine(
 		chatModel:            chatModel,
 		eventBus:             eventBus,
 		knowledgeBasesInfo:   knowledgeBasesInfo,
+		selectedDocs:         selectedDocs,
 		contextManager:       contextManager,
 		sessionID:            sessionID,
 		systemPromptTemplate: systemPromptTemplate,
@@ -99,6 +102,7 @@ func (e *AgentEngine) Execute(
 	systemPrompt := BuildSystemPrompt(
 		e.knowledgeBasesInfo,
 		e.config.WebSearchEnabled,
+		e.selectedDocs,
 		e.systemPromptTemplate,
 	)
 	logger.Debugf(ctx, "[Agent] SystemPrompt Length: %d characters", len(systemPrompt))
@@ -774,6 +778,7 @@ func (e *AgentEngine) streamFinalAnswerToEventBus(
 	systemPrompt := BuildSystemPrompt(
 		e.knowledgeBasesInfo,
 		e.config.WebSearchEnabled,
+		e.selectedDocs,
 		e.systemPromptTemplate,
 	)
 
diff --git a/internal/agent/prompts.go b/internal/agent/prompts.go
index ec50b389d..ea60f3930 100644
--- a/internal/agent/prompts.go
+++ b/internal/agent/prompts.go
@@ -57,6 +57,16 @@ type RecentDocInfo struct {
 	FAQAnswers          []string
 }
 
+// SelectedDocumentInfo contains summary information about a user-selected document (via @ mention)
+// Only metadata is included; content will be fetched via tools when needed
+type SelectedDocumentInfo struct {
+	KnowledgeID     string // Knowledge ID
+	KnowledgeBaseID string // Knowledge base ID
+	Title           string // Document title
+	FileName        string // Original file name
+	FileType        string // File type (pdf, docx, etc.)
+}
+
 // KnowledgeBaseInfo contains essential information about a knowledge base for agent prompt
 type KnowledgeBaseInfo struct {
 	ID          string
@@ -102,7 +112,8 @@ func formatKnowledgeBaseList(kbInfos []*KnowledgeBaseInfo) string {
 	}
 
 	var builder strings.Builder
-	builder.WriteString("\n")
+	builder.WriteString("\nThe following knowledge bases have been selected by the user for this conversation. ")
+	builder.WriteString("You should search within these knowledge bases to find relevant information.\n\n")
 	for i, kb := range kbInfos {
 		// Display knowledge base name and ID
 		builder.WriteString(fmt.Sprintf("%d. **%s** (knowledge_base_id: `%s`)\n", i+1, kb.Name, kb.ID))
@@ -184,6 +195,38 @@ func renderPromptPlaceholders(template string, knowledgeBases []*KnowledgeBaseIn
 	return result
 }
 
+// formatSelectedDocuments formats selected documents for the prompt (summary only, no content)
+func formatSelectedDocuments(docs []*SelectedDocumentInfo) string {
+	if len(docs) == 0 {
+		return ""
+	}
+
+	var builder strings.Builder
+	builder.WriteString("\n### User Selected Documents (via @ mention)\n")
+	builder.WriteString("The user has explicitly selected the following documents. ")
+	builder.WriteString("**You should prioritize searching and retrieving information from these documents when answering.**\n")
+	builder.WriteString("Use `list_knowledge_chunks` with the provided Knowledge IDs to fetch their content.\n\n")
+
+	builder.WriteString("| # | Document Name | Type | Knowledge ID |\n")
+	builder.WriteString("|---|---------------|------|---------------|\n")
+
+	for i, doc := range docs {
+		title := doc.Title
+		if title == "" {
+			title = doc.FileName
+		}
+		fileType := doc.FileType
+		if fileType == "" {
+			fileType = "-"
+		}
+		builder.WriteString(fmt.Sprintf("| %d | %s | %s | `%s` |\n",
+			i+1, title, fileType, doc.KnowledgeID))
+	}
+	builder.WriteString("\n")
+
+	return builder.String()
+}
+
 // renderPromptPlaceholdersWithStatus renders placeholders including web search status
 // Supported placeholders:
 //   - {{knowledge_bases}}
@@ -239,19 +282,72 @@ func BuildSystemPromptWithoutWeb(
 	return renderPromptPlaceholdersWithStatus(template, knowledgeBases, false, currentTime)
 }
 
+// BuildPureAgentSystemPrompt builds the system prompt for Pure Agent mode (no KBs)
+func BuildPureAgentSystemPrompt(
+	webSearchEnabled bool,
+	systemPromptTemplate ...string,
+) string {
+	var template string
+	if len(systemPromptTemplate) > 0 && systemPromptTemplate[0] != "" {
+		template = systemPromptTemplate[0]
+	} else {
+		template = PureAgentSystemPrompt
+	}
+	currentTime := time.Now().Format(time.RFC3339)
+	// Pass empty KB list
+	return renderPromptPlaceholdersWithStatus(template, []*KnowledgeBaseInfo{}, webSearchEnabled, currentTime)
+}
+
 // BuildProgressiveRAGSystemPrompt builds the progressive RAG system prompt based on web search status
 // This is the main function to use - it automatically selects the appropriate version
 func BuildSystemPrompt(
 	knowledgeBases []*KnowledgeBaseInfo,
 	webSearchEnabled bool,
+	selectedDocs []*SelectedDocumentInfo,
 	systemPromptTemplate ...string,
 ) string {
-	if webSearchEnabled {
-		return BuildSystemPromptWithWeb(knowledgeBases, systemPromptTemplate...)
+	var basePrompt string
+
+	// If no knowledge bases, use Pure Agent prompt
+	if len(knowledgeBases) == 0 {
+		basePrompt = BuildPureAgentSystemPrompt(webSearchEnabled, systemPromptTemplate...)
+	} else if webSearchEnabled {
+		basePrompt = BuildSystemPromptWithWeb(knowledgeBases, systemPromptTemplate...)
+	} else {
+		basePrompt = BuildSystemPromptWithoutWeb(knowledgeBases, systemPromptTemplate...)
 	}
-	return BuildSystemPromptWithoutWeb(knowledgeBases, systemPromptTemplate...)
+
+	// Append selected documents section if any
+	if len(selectedDocs) > 0 {
+		basePrompt += formatSelectedDocuments(selectedDocs)
+	}
+
+	return basePrompt
 }
 
+// PureAgentSystemPrompt is the system prompt for Pure Agent mode (no Knowledge Bases)
+var PureAgentSystemPrompt = `### Role
+You are WeKnora, an intelligent assistant powered by ReAct. You operate in a Pure Agent mode without attached Knowledge Bases.
+
+### Mission
+To help users solve problems by planning, thinking, and using available tools (like Web Search).
+
+### Workflow
+1.  **Analyze:** Understand the user's request.
+2.  **Plan:** If the task is complex, use todo_write to create a plan.
+3.  **Execute:** Use available tools to gather information or perform actions.
+4.  **Synthesize:** Provide a comprehensive answer.
+
+### Tool Guidelines
+*   **web_search / web_fetch:** Use these if enabled to find information from the internet.
+*   **todo_write:** Use for managing multi-step tasks.
+*   **thinking:** Use to plan and reflect.
+
+### System Status
+Current Time: {{current_time}}
+Web Search: {{web_search_status}}
+`
+
 // ProgressiveRAGSystemPromptWithWeb is the progressive RAG system prompt template with web search enabled
 // This version emphasizes hybrid retrieval strategy: KB-first with web supplementation
 var ProgressiveRAGSystemPromptWithWeb = `### Role
@@ -324,7 +420,9 @@ For every retrieval attempt (Phase 1 or Phase 3), follow this exact chain:
 
 ### System Status
 Current Time: {{current_time}}
-Knowledge Bases: {{knowledge_bases}}
+
+### User Selected Knowledge Bases (via @ mention)
+{{knowledge_bases}}
 `
 
 // ProgressiveRAGSystemPromptWithoutWeb is the progressive RAG system prompt template without web search
@@ -407,5 +505,7 @@ For every information seeking step, strictly follow this 3-step atomic unit:
 
 ### System Status
 Current Time: {{current_time}}
-Knowledge Bases: {{knowledge_bases}}
+
+### User Selected Knowledge Bases (via @ mention)
+{{knowledge_bases}}
 `
diff --git a/internal/agent/tools/grep_chunks.go b/internal/agent/tools/grep_chunks.go
index 76f810a43..af5abe3ce 100644
--- a/internal/agent/tools/grep_chunks.go
+++ b/internal/agent/tools/grep_chunks.go
@@ -20,10 +20,11 @@ type GrepChunksTool struct {
 	db               *gorm.DB
 	tenantID         uint64
 	knowledgeBaseIDs []string
+	knowledgeIDs     []string // Specific knowledge/document IDs to search within
 }
 
 // NewGrepChunksTool creates a new grep chunks tool
-func NewGrepChunksTool(db *gorm.DB, tenantID uint64, knowledgeBaseIDs []string) *GrepChunksTool {
+func NewGrepChunksTool(db *gorm.DB, tenantID uint64, knowledgeBaseIDs []string, knowledgeIDs []string) *GrepChunksTool {
 	description := `Unix-style text pattern matching tool for knowledge base chunks.
 
 Searches for text patterns in chunk content using strict literal text matching (fixed-string search). This tool performs exact keyword lookup, not semantic search.
@@ -68,6 +69,7 @@ grep_chunks scans enabled chunks across the specified knowledge bases and return
 		db:               db,
 		tenantID:         tenantID,
 		knowledgeBaseIDs: knowledgeBaseIDs,
+		knowledgeIDs:     knowledgeIDs,
 	}
 }
 
@@ -173,11 +175,11 @@ func (t *GrepChunksTool) Execute(ctx context.Context, args map[string]interface{
 	// 	}
 	// }
 
-	logger.Infof(ctx, "[Tool][GrepChunks] Patterns: %v, MaxResults: %d",
-		patterns, maxResults)
+	logger.Infof(ctx, "[Tool][GrepChunks] Patterns: %v, MaxResults: %d, KnowledgeIDs: %v",
+		patterns, maxResults, t.knowledgeIDs)
 
 	// Build and execute query
-	results, totalCount, err := t.searchChunks(ctx, patterns, kbIDs)
+	results, totalCount, err := t.searchChunks(ctx, patterns, kbIDs, t.knowledgeIDs)
 	if err != nil {
 		logger.Errorf(ctx, "[Tool][GrepChunks] Search failed: %v", err)
 		return &types.ToolResult{
@@ -269,6 +271,7 @@ func (t *GrepChunksTool) searchChunks(
 	ctx context.Context,
 	patterns []string,
 	kbIDs []string,
+	knowledgeIDs []string,
 ) ([]chunkWithTitle, int64, error) {
 	// Build base query
 	query := t.db.Debug().WithContext(ctx).Table("chunks").
@@ -279,8 +282,12 @@ func (t *GrepChunksTool) searchChunks(
 		Where("chunks.deleted_at IS NULL").
 		Where("knowledges.deleted_at IS NULL")
 
-	// Apply knowledge base filter
-	if len(kbIDs) > 0 {
+	// Apply knowledge IDs filter (specific documents) - takes priority over KB filter
+	if len(knowledgeIDs) > 0 {
+		query = query.Where("chunks.knowledge_id IN ?", knowledgeIDs)
+		logger.Infof(ctx, "[Tool][GrepChunks] Filtering by %d specific knowledge IDs", len(knowledgeIDs))
+	} else if len(kbIDs) > 0 {
+		// Apply knowledge base filter only if no specific knowledge IDs
 		query = query.Where("chunks.knowledge_base_id IN ?", kbIDs)
 	}
 
diff --git a/internal/agent/tools/knowledge_search.go b/internal/agent/tools/knowledge_search.go
index e6b590f9e..79482b900 100644
--- a/internal/agent/tools/knowledge_search.go
+++ b/internal/agent/tools/knowledge_search.go
@@ -32,9 +32,10 @@ type searchResultWithMeta struct {
 type KnowledgeSearchTool struct {
 	BaseTool
 	knowledgeBaseService interfaces.KnowledgeBaseService
+	knowledgeService     interfaces.KnowledgeService
 	chunkService         interfaces.ChunkService
 	tenantID             uint64
-	allowedKBs           []string
+	searchTargets        types.SearchTargets // Pre-computed unified search targets
 	rerankModel          rerank.Reranker
 	chatModel            chat.Chat      // Optional chat model for LLM-based reranking
 	config               *config.Config // Global config for fallback values
@@ -43,9 +44,10 @@ type KnowledgeSearchTool struct {
 // NewKnowledgeSearchTool creates a new knowledge search tool
 func NewKnowledgeSearchTool(
 	knowledgeBaseService interfaces.KnowledgeBaseService,
+	knowledgeService interfaces.KnowledgeService,
 	chunkService interfaces.ChunkService,
 	tenantID uint64,
-	allowedKBs []string,
+	searchTargets types.SearchTargets,
 	rerankModel rerank.Reranker,
 	chatModel chat.Chat,
 	cfg *config.Config,
@@ -110,9 +112,10 @@ Results represent conceptual relevance, not literal keyword overlap.
 	return &KnowledgeSearchTool{
 		BaseTool:             NewBaseTool("knowledge_search", description),
 		knowledgeBaseService: knowledgeBaseService,
+		knowledgeService:     knowledgeService,
 		chunkService:         chunkService,
 		tenantID:             tenantID,
-		allowedKBs:           allowedKBs,
+		searchTargets:        searchTargets,
 		rerankModel:          rerankModel,
 		chatModel:            chatModel,
 		config:               cfg,
@@ -155,30 +158,46 @@ func (t *KnowledgeSearchTool) Execute(ctx context.Context, args map[string]inter
 	argsJSON, _ := json.MarshalIndent(args, "", "  ")
 	logger.Debugf(ctx, "[Tool][KnowledgeSearch] Input args:\n%s", string(argsJSON))
 
-	// Determine which KBs to search
-	var kbIDs []string
+	// Determine which KBs to search - user can optionally filter to specific KBs
+	var userSpecifiedKBs []string
 	if kbIDsRaw, ok := args["knowledge_base_ids"].([]interface{}); ok && len(kbIDsRaw) > 0 {
 		for _, id := range kbIDsRaw {
 			if idStr, ok := id.(string); ok && idStr != "" {
-				kbIDs = append(kbIDs, idStr)
+				userSpecifiedKBs = append(userSpecifiedKBs, idStr)
 			}
 		}
-		logger.Infof(ctx, "[Tool][KnowledgeSearch] User specified %d knowledge bases: %v", len(kbIDs), kbIDs)
+		logger.Infof(ctx, "[Tool][KnowledgeSearch] User specified %d knowledge bases: %v", len(userSpecifiedKBs), userSpecifiedKBs)
 	}
 
-	// If no KBs specified, use allowed KBs
-	if len(kbIDs) == 0 {
-		kbIDs = t.allowedKBs
-		if len(kbIDs) == 0 {
-			logger.Errorf(ctx, "[Tool][KnowledgeSearch] No knowledge bases available")
-			return &types.ToolResult{
-				Success: false,
-				Error:   "no knowledge bases specified and no allowed KBs configured",
-			}, fmt.Errorf("no knowledge bases available")
+	// Use pre-computed search targets, optionally filtered by user-specified KBs
+	searchTargets := t.searchTargets
+	if len(userSpecifiedKBs) > 0 {
+		// Filter search targets to only include user-specified KBs
+		userKBSet := make(map[string]bool)
+		for _, kbID := range userSpecifiedKBs {
+			userKBSet[kbID] = true
 		}
-		logger.Infof(ctx, "[Tool][KnowledgeSearch] Using all allowed KBs (%d): %v", len(kbIDs), kbIDs)
+		var filteredTargets types.SearchTargets
+		for _, target := range t.searchTargets {
+			if userKBSet[target.KnowledgeBaseID] {
+				filteredTargets = append(filteredTargets, target)
+			}
+		}
+		searchTargets = filteredTargets
 	}
 
+	// Validate search targets
+	if len(searchTargets) == 0 {
+		logger.Errorf(ctx, "[Tool][KnowledgeSearch] No search targets available")
+		return &types.ToolResult{
+			Success: false,
+			Error:   "no knowledge bases specified and no search targets configured",
+		}, fmt.Errorf("no search targets available")
+	}
+
+	kbIDs := searchTargets.GetAllKnowledgeBaseIDs()
+	logger.Infof(ctx, "[Tool][KnowledgeSearch] Using %d search targets across %d KBs", len(searchTargets), len(kbIDs))
+
 	// Parse query parameter
 	var queries []string
 	if queriesRaw, ok := args["queries"].([]interface{}); ok && len(queriesRaw) > 0 {
@@ -256,11 +275,12 @@ func (t *KnowledgeSearchTool) Execute(ctx context.Context, args map[string]inter
 		minScore,
 	)
 
-	// Execute concurrent search (hybrid search handles both vector and keyword)
-	logger.Infof(ctx, "[Tool][KnowledgeSearch] Starting concurrent search across %d KBs", len(kbIDs))
+	// Execute concurrent search using pre-computed search targets
+	logger.Infof(ctx, "[Tool][KnowledgeSearch] Starting concurrent search with %d search targets",
+		len(searchTargets))
 	kbTypeMap := t.getKnowledgeBaseTypes(ctx, kbIDs)
 
-	allResults := t.concurrentSearch(ctx, queries, kbIDs,
+	allResults := t.concurrentSearchByTargets(ctx, queries, searchTargets,
 		topK, vectorThreshold, keywordThreshold, kbTypeMap)
 	logger.Infof(ctx, "[Tool][KnowledgeSearch] Concurrent search completed: %d raw results", len(allResults))
 
@@ -410,11 +430,12 @@ func (t *KnowledgeSearchTool) getKnowledgeBaseTypes(ctx context.Context, kbIDs [
 	return kbTypeMap
 }
 
-// concurrentSearch executes hybrid search across multiple KBs concurrently
-func (t *KnowledgeSearchTool) concurrentSearch(
+// concurrentSearchByTargets executes hybrid search using pre-computed search targets
+// This avoids duplicate searches when a knowledge file is already covered by its KB's full search
+func (t *KnowledgeSearchTool) concurrentSearchByTargets(
 	ctx context.Context,
 	queries []string,
-	kbsToSearch []string,
+	searchTargets types.SearchTargets,
 	topK int,
 	vectorThreshold, keywordThreshold float64,
 	kbTypeMap map[string]string,
@@ -424,24 +445,28 @@ func (t *KnowledgeSearchTool) concurrentSearch(
 	allResults := make([]*searchResultWithMeta, 0)
 
 	for _, query := range queries {
-		// Capture query in local variable to avoid closure issues
 		q := query
-		for _, kbID := range kbsToSearch {
-			// Capture kbID in local variable to avoid closure issues
-			kb := kbID
+		for _, target := range searchTargets {
+			st := target
 			wg.Add(1)
 			go func() {
 				defer wg.Done()
+
 				searchParams := types.SearchParams{
 					QueryText:        q,
 					MatchCount:       topK,
 					VectorThreshold:  vectorThreshold,
 					KeywordThreshold: keywordThreshold,
 				}
-				kbResults, err := t.knowledgeBaseService.HybridSearch(ctx, kb, searchParams)
+
+				// If target has specific knowledge IDs, add them to search params
+				if st.Type == types.SearchTargetTypeKnowledge {
+					searchParams.KnowledgeIDs = st.KnowledgeIDs
+				}
+
+				kbResults, err := t.knowledgeBaseService.HybridSearch(ctx, st.KnowledgeBaseID, searchParams)
 				if err != nil {
-					// Log error but continue with other KBs
-					logger.Warnf(ctx, "[Tool][KnowledgeSearch] Failed to search knowledge base %s: %v", kb, err)
+					logger.Warnf(ctx, "[Tool][KnowledgeSearch] Failed to search KB %s: %v", st.KnowledgeBaseID, err)
 					return
 				}
 
@@ -451,9 +476,9 @@ func (t *KnowledgeSearchTool) concurrentSearch(
 					allResults = append(allResults, &searchResultWithMeta{
 						SearchResult:      r,
 						SourceQuery:       q,
-						QueryType:         "hybrid", // Hybrid search combines both vector and keyword
-						KnowledgeBaseID:   kb,
-						KnowledgeBaseType: kbTypeMap[kb],
+						QueryType:         "hybrid",
+						KnowledgeBaseID:   st.KnowledgeBaseID,
+						KnowledgeBaseType: kbTypeMap[st.KnowledgeBaseID],
 					})
 				}
 				mu.Unlock()
@@ -470,34 +495,36 @@ func (t *KnowledgeSearchTool) rerankResults(
 	query string,
 	results []*searchResultWithMeta,
 ) ([]*searchResultWithMeta, error) {
-	// Separate FAQ and non-FAQ results. FAQ results keep original scores.
+	// Separate FAQ and normal results.
+	// FAQ results keep original scores and bypass reranking model.
 	faqResults := make([]*searchResultWithMeta, 0)
-	nonFAQResults := make([]*searchResultWithMeta, 0, len(results))
+	rerankCandidates := make([]*searchResultWithMeta, 0, len(results))
 
 	for _, result := range results {
+		// Skip reranking for FAQ results (they are explicitly matched Q&A pairs)
 		if result.KnowledgeBaseType == types.KnowledgeBaseTypeFAQ {
 			faqResults = append(faqResults, result)
 		} else {
-			nonFAQResults = append(nonFAQResults, result)
+			rerankCandidates = append(rerankCandidates, result)
 		}
 	}
 
-	// If there are no non-FAQ results, return original list (already all FAQ)
-	if len(nonFAQResults) == 0 {
+	// If there are no candidates to rerank, return original list (already all FAQ)
+	if len(rerankCandidates) == 0 {
 		return results, nil
 	}
 
 	var (
-		rerankedNonFAQ []*searchResultWithMeta
-		err            error
+		rerankedCandidates []*searchResultWithMeta
+		err                error
 	)
 
-	// Apply reranking only to non-FAQ results
+	// Apply reranking only to candidates
 	// Try rerankModel first, fallback to chatModel if rerankModel fails or returns no results
 	if t.rerankModel != nil {
-		rerankedNonFAQ, err = t.rerankWithModel(ctx, query, nonFAQResults)
+		rerankedCandidates, err = t.rerankWithModel(ctx, query, rerankCandidates)
 		// If rerankModel fails or returns no results, fallback to chatModel
-		if err != nil || len(rerankedNonFAQ) == 0 {
+		if err != nil || len(rerankedCandidates) == 0 {
 			if err != nil {
 				logger.Warnf(ctx, "[Tool][KnowledgeSearch] Rerank model failed, falling back to chat model: %v", err)
 			} else {
@@ -507,18 +534,18 @@ func (t *KnowledgeSearchTool) rerankResults(
 			err = nil
 			// Try chatModel if available
 			if t.chatModel != nil {
-				rerankedNonFAQ, err = t.rerankWithLLM(ctx, query, nonFAQResults)
+				rerankedCandidates, err = t.rerankWithLLM(ctx, query, rerankCandidates)
 			} else {
 				// No fallback available, use original results
-				rerankedNonFAQ = nonFAQResults
+				rerankedCandidates = rerankCandidates
 			}
 		}
 	} else if t.chatModel != nil {
 		// No rerankModel, use chatModel directly
-		rerankedNonFAQ, err = t.rerankWithLLM(ctx, query, nonFAQResults)
+		rerankedCandidates, err = t.rerankWithLLM(ctx, query, rerankCandidates)
 	} else {
 		// No reranking available, use original results
-		rerankedNonFAQ = nonFAQResults
+		rerankedCandidates = rerankCandidates
 	}
 
 	if err != nil {
@@ -529,16 +556,16 @@ func (t *KnowledgeSearchTool) rerankResults(
 	logger.Debugf(ctx, "[Tool][KnowledgeSearch] Applying composite scoring")
 
 	// Store base scores before composite scoring
-	for _, result := range rerankedNonFAQ {
+	for _, result := range rerankedCandidates {
 		baseScore := result.Score
 		// Apply composite score
 		result.Score = t.compositeScore(result, result.Score, baseScore)
 	}
 
-	// Combine FAQ results (with original order) and reranked non-FAQ results
+	// Combine FAQ results (with original order) and reranked candidates
 	combined := make([]*searchResultWithMeta, 0, len(results))
 	combined = append(combined, faqResults...)
-	combined = append(combined, rerankedNonFAQ...)
+	combined = append(combined, rerankedCandidates...)
 
 	// Sort by score (descending) to keep consistent output order
 	sort.Slice(combined, func(i, j int) bool {
diff --git a/internal/application/repository/knowledge.go b/internal/application/repository/knowledge.go
index fb5133f15..4640c8fd1 100644
--- a/internal/application/repository/knowledge.go
+++ b/internal/application/repository/knowledge.go
@@ -292,3 +292,58 @@ func (r *knowledgeRepository) CountKnowledgeByStatus(
 
 	return count, nil
 }
+
+// SearchKnowledge searches knowledge items by keyword across the tenant
+// If keyword is empty, returns recent files
+// Only returns documents from document-type knowledge bases (excludes FAQ)
+// Returns (results, hasMore, error)
+func (r *knowledgeRepository) SearchKnowledge(
+	ctx context.Context,
+	tenantID uint64,
+	keyword string,
+	offset, limit int,
+) ([]*types.Knowledge, bool, error) {
+	// Use raw query to properly map knowledge_base_name
+	type KnowledgeWithKBName struct {
+		types.Knowledge
+		KnowledgeBaseName string `gorm:"column:knowledge_base_name"`
+	}
+
+	var results []KnowledgeWithKBName
+	query := r.db.WithContext(ctx).
+		Table("knowledges").
+		Select("knowledges.*, knowledge_bases.name as knowledge_base_name").
+		Joins("JOIN knowledge_bases ON knowledge_bases.id = knowledges.knowledge_base_id").
+		Where("knowledges.tenant_id = ?", tenantID).
+		Where("knowledge_bases.type = ?", types.KnowledgeBaseTypeDocument).
+		Where("knowledges.deleted_at IS NULL")
+
+	// If keyword is provided, filter by file_name or title
+	if keyword != "" {
+		query = query.Where("knowledges.file_name LIKE ? ", "%"+keyword+"%")
+	}
+
+	// Fetch limit+1 to check if there are more results
+	err := query.Order("knowledges.created_at DESC").
+		Offset(offset).
+		Limit(limit + 1).
+		Scan(&results).Error
+	if err != nil {
+		return nil, false, err
+	}
+
+	// Check if there are more results
+	hasMore := len(results) > limit
+	if hasMore {
+		results = results[:limit]
+	}
+
+	// Convert to []*types.Knowledge
+	knowledges := make([]*types.Knowledge, len(results))
+	for i, r := range results {
+		k := r.Knowledge
+		k.KnowledgeBaseName = r.KnowledgeBaseName
+		knowledges[i] = &k
+	}
+	return knowledges, hasMore, nil
+}
diff --git a/internal/application/repository/knowledgebase.go b/internal/application/repository/knowledgebase.go
index 36e125186..fff4be132 100644
--- a/internal/application/repository/knowledgebase.go
+++ b/internal/application/repository/knowledgebase.go
@@ -38,6 +38,18 @@ func (r *knowledgeBaseRepository) GetKnowledgeBaseByID(ctx context.Context, id s
 	return &kb, nil
 }
 
+// GetKnowledgeBaseByIDs gets knowledge bases by multiple ids
+func (r *knowledgeBaseRepository) GetKnowledgeBaseByIDs(ctx context.Context, ids []string) ([]*types.KnowledgeBase, error) {
+	if len(ids) == 0 {
+		return []*types.KnowledgeBase{}, nil
+	}
+	var kbs []*types.KnowledgeBase
+	if err := r.db.WithContext(ctx).Where("id IN ?", ids).Find(&kbs).Error; err != nil {
+		return nil, err
+	}
+	return kbs, nil
+}
+
 // ListKnowledgeBases lists all knowledge bases
 func (r *knowledgeBaseRepository) ListKnowledgeBases(ctx context.Context) ([]*types.KnowledgeBase, error) {
 	var kbs []*types.KnowledgeBase
diff --git a/internal/application/repository/retriever/elasticsearch/v7/repository.go b/internal/application/repository/retriever/elasticsearch/v7/repository.go
index 60c6747fe..df624674b 100644
--- a/internal/application/repository/retriever/elasticsearch/v7/repository.go
+++ b/internal/application/repository/retriever/elasticsearch/v7/repository.go
@@ -355,10 +355,16 @@ func (e *elasticsearchRepository) deleteByFieldList(ctx context.Context, field s
 
 // getBaseConds Construct base Elasticsearch query conditions based on retrieval parameters
 // It creates MUST conditions for required fields and MUST_NOT conditions for excluded fields
+// KnowledgeBaseIDs and KnowledgeIDs use AND logic (search specific documents within knowledge bases)
 // Returns a JSON string representing the query conditions
 func (e *elasticsearchRepository) getBaseConds(params typesLocal.RetrieveParams) string {
 	// Build MUST conditions (positive filters)
 	must := make([]map[string]interface{}, 0)
+
+	// KnowledgeBaseIDs and KnowledgeIDs use AND logic
+	// - If only KnowledgeBaseIDs: search entire knowledge bases
+	// - If only KnowledgeIDs: search specific documents
+	// - If both: search specific documents within the knowledge bases (AND)
 	if len(params.KnowledgeBaseIDs) > 0 {
 		must = append(must, map[string]interface{}{
 			"terms": map[string]interface{}{
@@ -366,6 +372,13 @@ func (e *elasticsearchRepository) getBaseConds(params typesLocal.RetrieveParams)
 			},
 		})
 	}
+	if len(params.KnowledgeIDs) > 0 {
+		must = append(must, map[string]interface{}{
+			"terms": map[string]interface{}{
+				"knowledge_id.keyword": params.KnowledgeIDs,
+			},
+		})
+	}
 
 	// Build MUST_NOT conditions (negative filters)
 	mustNot := make([]map[string]interface{}, 0)
diff --git a/internal/application/repository/retriever/elasticsearch/v8/repository.go b/internal/application/repository/retriever/elasticsearch/v8/repository.go
index a73986d1a..adfe13dc6 100644
--- a/internal/application/repository/retriever/elasticsearch/v8/repository.go
+++ b/internal/application/repository/retriever/elasticsearch/v8/repository.go
@@ -236,8 +236,14 @@ func (e *elasticsearchRepository) DeleteByKnowledgeIDList(ctx context.Context,
 
 // getBaseConds creates the base query conditions for retrieval operations
 // Returns a slice of Query objects with must and must_not conditions
+// KnowledgeBaseIDs and KnowledgeIDs use AND logic (search specific documents within knowledge bases)
 func (e *elasticsearchRepository) getBaseConds(params typesLocal.RetrieveParams) []types.Query {
 	must := []types.Query{}
+
+	// KnowledgeBaseIDs and KnowledgeIDs use AND logic
+	// - If only KnowledgeBaseIDs: search entire knowledge bases
+	// - If only KnowledgeIDs: search specific documents
+	// - If both: search specific documents within the knowledge bases (AND)
 	if len(params.KnowledgeBaseIDs) > 0 {
 		must = append(must, types.Query{Terms: &types.TermsQuery{
 			TermsQuery: map[string]types.TermsQueryField{
@@ -245,6 +251,14 @@ func (e *elasticsearchRepository) getBaseConds(params typesLocal.RetrieveParams)
 			},
 		}})
 	}
+	if len(params.KnowledgeIDs) > 0 {
+		must = append(must, types.Query{Terms: &types.TermsQuery{
+			TermsQuery: map[string]types.TermsQueryField{
+				"knowledge_id.keyword": params.KnowledgeIDs,
+			},
+		}})
+	}
+
 	mustNot := make([]types.Query, 0)
 	// Exclude disabled chunks (is_enabled = false)
 	// Note: Historical data without is_enabled field will be included (not matching must_not)
diff --git a/internal/application/repository/retriever/postgres/repository.go b/internal/application/repository/retriever/postgres/repository.go
index 773203f03..b974fd6e3 100644
--- a/internal/application/repository/retriever/postgres/repository.go
+++ b/internal/application/repository/retriever/postgres/repository.go
@@ -166,14 +166,25 @@ func (g *pgRepository) KeywordsRetrieve(ctx context.Context,
 ) ([]*types.RetrieveResult, error) {
 	logger.GetLogger(ctx).Infof("[Postgres] Keywords retrieval: query=%s, topK=%d", params.Query, params.TopK)
 	conds := make([]clause.Expression, 0)
+
+	// KnowledgeBaseIDs and KnowledgeIDs use AND logic
+	// - If only KnowledgeBaseIDs: search entire knowledge bases
+	// - If only KnowledgeIDs: search specific documents
+	// - If both: search specific documents within the knowledge bases (AND)
 	if len(params.KnowledgeBaseIDs) > 0 {
 		logger.GetLogger(ctx).Debugf("[Postgres] Filtering by knowledge base IDs: %v", params.KnowledgeBaseIDs)
-		// Use standard SQL IN clause instead of @@@ operator for better performance with B-tree index
 		conds = append(conds, clause.IN{
 			Column: "knowledge_base_id",
 			Values: common.ToInterfaceSlice(params.KnowledgeBaseIDs),
 		})
 	}
+	if len(params.KnowledgeIDs) > 0 {
+		logger.GetLogger(ctx).Debugf("[Postgres] Filtering by knowledge IDs: %v", params.KnowledgeIDs)
+		conds = append(conds, clause.IN{
+			Column: "knowledge_id",
+			Values: common.ToInterfaceSlice(params.KnowledgeIDs),
+		})
+	}
 	conds = append(conds, clause.Expr{
 		SQL:  "id @@@ paradedb.match(field => 'content', value => ?, distance => 1)",
 		Vars: []interface{}{params.Query},
@@ -250,13 +261,15 @@ func (g *pgRepository) VectorRetrieve(ctx context.Context,
 	whereParts = append(whereParts, fmt.Sprintf("dimension = $%d", len(allVars)+1))
 	allVars = append(allVars, dimension)
 
-	// Knowledge base filter
+	// KnowledgeBaseIDs and KnowledgeIDs use AND logic
+	// - If only KnowledgeBaseIDs: search entire knowledge bases
+	// - If only KnowledgeIDs: search specific documents
+	// - If both: search specific documents within the knowledge bases (AND)
 	if len(params.KnowledgeBaseIDs) > 0 {
 		logger.GetLogger(ctx).Debugf(
 			"[Postgres] Filtering vector search by knowledge base IDs: %v",
 			params.KnowledgeBaseIDs,
 		)
-		// Build IN clause with proper placeholders
 		placeholders := make([]string, len(params.KnowledgeBaseIDs))
 		paramStart := len(allVars) + 1
 		for i := range params.KnowledgeBaseIDs {
@@ -266,6 +279,20 @@ func (g *pgRepository) VectorRetrieve(ctx context.Context,
 		whereParts = append(whereParts, fmt.Sprintf("knowledge_base_id IN (%s)",
 			strings.Join(placeholders, ", ")))
 	}
+	if len(params.KnowledgeIDs) > 0 {
+		logger.GetLogger(ctx).Debugf(
+			"[Postgres] Filtering vector search by knowledge IDs: %v",
+			params.KnowledgeIDs,
+		)
+		placeholders := make([]string, len(params.KnowledgeIDs))
+		paramStart := len(allVars) + 1
+		for i := range params.KnowledgeIDs {
+			placeholders[i] = fmt.Sprintf("$%d", paramStart+i)
+			allVars = append(allVars, params.KnowledgeIDs[i])
+		}
+		whereParts = append(whereParts, fmt.Sprintf("knowledge_id IN (%s)",
+			strings.Join(placeholders, ", ")))
+	}
 
 	// is_enabled filter
 	whereParts = append(whereParts, fmt.Sprintf("(is_enabled IS NULL OR is_enabled = $%d)", len(allVars)+1))
diff --git a/internal/application/repository/retriever/qdrant/repository.go b/internal/application/repository/retriever/qdrant/repository.go
index 6d660d5ef..7ca72cf91 100644
--- a/internal/application/repository/retriever/qdrant/repository.go
+++ b/internal/application/repository/retriever/qdrant/repository.go
@@ -433,9 +433,16 @@ func (q *qdrantRepository) getBaseFilter(params types.RetrieveParams) *qdrant.Fi
 	// Only retrieve enabled chunks
 	must = append(must, qdrant.NewMatchBool(fieldIsEnabled, true))
 
+	// KnowledgeBaseIDs and KnowledgeIDs use AND logic
+	// - If only KnowledgeBaseIDs: search entire knowledge bases
+	// - If only KnowledgeIDs: search specific documents
+	// - If both: search specific documents within the knowledge bases (AND)
 	if len(params.KnowledgeBaseIDs) > 0 {
 		must = append(must, qdrant.NewMatchKeywords(fieldKnowledgeBaseID, params.KnowledgeBaseIDs...))
 	}
+	if len(params.KnowledgeIDs) > 0 {
+		must = append(must, qdrant.NewMatchKeywords(fieldKnowledgeID, params.KnowledgeIDs...))
+	}
 
 	if len(params.ExcludeKnowledgeIDs) > 0 {
 		mustNot = append(mustNot, qdrant.NewMatchKeywords(fieldKnowledgeID, params.ExcludeKnowledgeIDs...))
@@ -445,10 +452,12 @@ func (q *qdrantRepository) getBaseFilter(params types.RetrieveParams) *qdrant.Fi
 		mustNot = append(mustNot, qdrant.NewMatchKeywords(fieldChunkID, params.ExcludeChunkIDs...))
 	}
 
-	return &qdrant.Filter{
+	filter := &qdrant.Filter{
 		Must:    must,
 		MustNot: mustNot,
 	}
+
+	return filter
 }
 
 // Retrieve dispatches the retrieval operation to the appropriate method based on retriever type
diff --git a/internal/application/service/agent_service.go b/internal/application/service/agent_service.go
index ced67a1aa..4edd15f0d 100644
--- a/internal/application/service/agent_service.go
+++ b/internal/application/service/agent_service.go
@@ -141,6 +141,13 @@ func (s *agentService) CreateAgentEngine(
 		}
 	}
 
+	// Get selected documents information (user @ mentioned documents)
+	selectedDocs, err := s.getSelectedDocumentInfos(ctx, config.KnowledgeIDs)
+	if err != nil {
+		logger.Warnf(ctx, "Failed to get selected document details: %v", err)
+		selectedDocs = []*agent.SelectedDocumentInfo{}
+	}
+
 	systemPromptTemplate := ""
 	if config.UseCustomSystemPrompt {
 		systemPromptTemplate = config.ResolveSystemPrompt(config.WebSearchEnabled)
@@ -153,6 +160,7 @@ func (s *agentService) CreateAgentEngine(
 		toolRegistry,
 		eventBus,
 		kbInfos,
+		selectedDocs,
 		contextManager,
 		sessionID,
 		systemPromptTemplate,
@@ -173,6 +181,29 @@ func (s *agentService) registerTools(
 ) error {
 	// If no specific tools allowed, register default tools
 	allowedTools := tools.DefaultAllowedTools()
+
+	// Filter out knowledge base tools if no knowledge bases or knowledge IDs are configured
+	hasKnowledge := len(config.KnowledgeBases) > 0 || len(config.KnowledgeIDs) > 0
+	if !hasKnowledge {
+		filteredTools := make([]string, 0)
+		kbTools := map[string]bool{
+			"knowledge_search":      true,
+			"grep_chunks":           true,
+			"list_knowledge_chunks": true,
+			"query_knowledge_graph": true,
+			"get_document_info":     true,
+			"database_query":        true,
+		}
+
+		for _, toolName := range allowedTools {
+			if !kbTools[toolName] {
+				filteredTools = append(filteredTools, toolName)
+			}
+		}
+		allowedTools = filteredTools
+		logger.Infof(ctx, "Pure Agent Mode: Knowledge base tools disabled due to empty configuration")
+	}
+
 	// If web search is enabled, add web_search to allowedTools
 	if config.WebSearchEnabled {
 		allowedTools = append(allowedTools, "web_search")
@@ -203,16 +234,17 @@ func (s *agentService) registerTools(
 			registry.RegisterTool(
 				tools.NewKnowledgeSearchTool(
 					s.knowledgeBaseService,
+					s.knowledgeService,
 					s.chunkService,
 					tenantID,
-					config.KnowledgeBases,
+					config.SearchTargets,
 					rerankModel,
 					chatModel,
 					s.cfg,
 				))
 		case "grep_chunks":
-			registry.RegisterTool(tools.NewGrepChunksTool(s.db, tenantID, config.KnowledgeBases))
-			logger.Infof(ctx, "Registered grep_chunks tool for tenant: %d", tenantID)
+			registry.RegisterTool(tools.NewGrepChunksTool(s.db, tenantID, config.KnowledgeBases, config.KnowledgeIDs))
+			logger.Infof(ctx, "Registered grep_chunks tool for tenant: %d, KBs: %d, KnowledgeIDs: %d", tenantID, len(config.KnowledgeBases), len(config.KnowledgeIDs))
 		case "list_knowledge_chunks":
 			registry.RegisterTool(tools.NewListKnowledgeChunksTool(tenantID, s.knowledgeService, s.chunkService))
 		case "query_knowledge_graph":
@@ -372,3 +404,54 @@ func (s *agentService) getKnowledgeBaseInfos(ctx context.Context, kbIDs []string
 
 	return kbInfos, nil
 }
+
+// getSelectedDocumentInfos retrieves detailed information for user-selected documents (via @ mention)
+// This loads the actual content of the documents to include in the system prompt
+func (s *agentService) getSelectedDocumentInfos(ctx context.Context, knowledgeIDs []string) ([]*agent.SelectedDocumentInfo, error) {
+	if len(knowledgeIDs) == 0 {
+		return []*agent.SelectedDocumentInfo{}, nil
+	}
+
+	// Get tenant ID from context
+	tenantID := uint64(0)
+	if tid, ok := ctx.Value(types.TenantIDContextKey).(uint64); ok {
+		tenantID = tid
+	}
+
+	// Fetch knowledge metadata
+	knowledges, err := s.knowledgeService.GetKnowledgeBatch(ctx, tenantID, knowledgeIDs)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get knowledge batch: %w", err)
+	}
+
+	// Build map for quick lookup
+	knowledgeMap := make(map[string]*types.Knowledge)
+	for _, k := range knowledges {
+		if k != nil {
+			knowledgeMap[k.ID] = k
+		}
+	}
+
+	selectedDocs := make([]*agent.SelectedDocumentInfo, 0, len(knowledgeIDs))
+
+	for _, kid := range knowledgeIDs {
+		k, ok := knowledgeMap[kid]
+		if !ok {
+			logger.Warnf(ctx, "Selected knowledge %s not found", kid)
+			continue
+		}
+
+		docInfo := &agent.SelectedDocumentInfo{
+			KnowledgeID:     k.ID,
+			KnowledgeBaseID: k.KnowledgeBaseID,
+			Title:           k.Title,
+			FileName:        k.FileName,
+			FileType:        k.FileType,
+		}
+
+		selectedDocs = append(selectedDocs, docInfo)
+	}
+
+	logger.Infof(ctx, "Loaded %d selected documents metadata for prompt", len(selectedDocs))
+	return selectedDocs, nil
+}
diff --git a/internal/application/service/chat_pipline/extract_entity.go b/internal/application/service/chat_pipline/extract_entity.go
index c23f451ee..e1f975712 100644
--- a/internal/application/service/chat_pipline/extract_entity.go
+++ b/internal/application/service/chat_pipline/extract_entity.go
@@ -22,6 +22,7 @@ type PluginExtractEntity struct {
 	modelService      interfaces.ModelService         // Model service for calling large language models
 	template          *types.PromptTemplateStructured // Template for generating prompts
 	knowledgeBaseRepo interfaces.KnowledgeBaseRepository
+	knowledgeRepo     interfaces.KnowledgeRepository
 }
 
 // NewPluginRewrite creates a new query rewriting plugin instance
@@ -30,12 +31,14 @@ func NewPluginExtractEntity(
 	eventManager *EventManager,
 	modelService interfaces.ModelService,
 	knowledgeBaseRepo interfaces.KnowledgeBaseRepository,
+	knowledgeRepo interfaces.KnowledgeRepository,
 	config *config.Config,
 ) *PluginExtractEntity {
 	res := &PluginExtractEntity{
 		modelService:      modelService,
 		template:          config.ExtractManager.ExtractEntity,
 		knowledgeBaseRepo: knowledgeBaseRepo,
+		knowledgeRepo:     knowledgeRepo,
 	}
 	eventManager.Register(res)
 	return res
@@ -65,16 +68,68 @@ func (p *PluginExtractEntity) OnEvent(ctx context.Context,
 		return next()
 	}
 
-	kb, err := p.knowledgeBaseRepo.GetKnowledgeBaseByID(ctx, chatManage.KnowledgeBaseID)
+	// Collect all knowledge base IDs to query
+	kbIDSet := make(map[string]struct{})
+	for _, id := range chatManage.KnowledgeBaseIDs {
+		kbIDSet[id] = struct{}{}
+	}
+
+	// If KnowledgeIDs is specified, retrieve them and collect their knowledge base IDs
+	// Also build a mapping from KnowledgeID to KnowledgeBaseID
+	knowledgeToKBMap := make(map[string]string)
+	if len(chatManage.KnowledgeIDs) > 0 {
+		knowledges, err := p.knowledgeRepo.GetKnowledgeBatch(ctx, chatManage.TenantID, chatManage.KnowledgeIDs)
+		if err != nil {
+			logger.Errorf(ctx, "failed to get knowledges: %v", err)
+			return next()
+		}
+		for _, k := range knowledges {
+			kbIDSet[k.KnowledgeBaseID] = struct{}{}
+			knowledgeToKBMap[k.ID] = k.KnowledgeBaseID
+		}
+	}
+
+	// Convert set to slice
+	allKBIDs := make([]string, 0, len(kbIDSet))
+	for id := range kbIDSet {
+		allKBIDs = append(allKBIDs, id)
+	}
+
+	// Batch retrieve all knowledge bases
+	kbs, err := p.knowledgeBaseRepo.GetKnowledgeBaseByIDs(ctx, allKBIDs)
 	if err != nil {
-		logger.Errorf(ctx, "failed to get knowledge base: %v", err)
+		logger.Errorf(ctx, "failed to get knowledge bases: %v", err)
 		return next()
 	}
-	if kb.ExtractConfig == nil {
-		logger.Warnf(ctx, "failed to get extract config")
+
+	// Check if any knowledge base has ExtractConfig enabled and collect their IDs
+	enabledKBSet := make(map[string]struct{})
+	for _, kb := range kbs {
+		if kb.ExtractConfig != nil && kb.ExtractConfig.Enabled {
+			enabledKBSet[kb.ID] = struct{}{}
+		}
+	}
+	if len(enabledKBSet) == 0 {
+		logger.Debugf(ctx, "no knowledge base has extract config enabled")
 		return next()
 	}
 
+	// Save enabled knowledge base IDs for later use in search_entity
+	enabledKBIDs := make([]string, 0, len(enabledKBSet))
+	for id := range enabledKBSet {
+		enabledKBIDs = append(enabledKBIDs, id)
+	}
+	chatManage.EntityKBIDs = enabledKBIDs
+
+	// Filter knowledgeToKBMap to only include files from enabled knowledge bases
+	entityKnowledge := make(map[string]string)
+	for knowledgeID, kbID := range knowledgeToKBMap {
+		if _, ok := enabledKBSet[kbID]; ok {
+			entityKnowledge[knowledgeID] = kbID
+		}
+	}
+	chatManage.EntityKnowledge = entityKnowledge
+
 	template := &types.PromptTemplateStructured{
 		Description: p.template.Description,
 		Examples:    p.template.Examples,
diff --git a/internal/application/service/chat_pipline/rerank.go b/internal/application/service/chat_pipline/rerank.go
index 7f2769ed7..d23103410 100644
--- a/internal/application/service/chat_pipline/rerank.go
+++ b/internal/application/service/chat_pipline/rerank.go
@@ -66,35 +66,54 @@ func (p *PluginRerank) OnEvent(ctx context.Context,
 		return ErrGetRerankModel.WithError(err)
 	}
 
-	// Prepare passages for reranking
-	pipelineInfo(ctx, "Rerank", "build_passages", map[string]interface{}{
-		"candidate_cnt": len(chatManage.SearchResult),
-	})
+	// Prepare passages for reranking (excluding DirectLoad results)
 	var passages []string
+	var candidatesToRerank []*types.SearchResult
+	var directLoadResults []*types.SearchResult
+
 	for _, result := range chatManage.SearchResult {
+		if result.MatchType == types.MatchTypeDirectLoad {
+			directLoadResults = append(directLoadResults, result)
+			pipelineInfo(ctx, "Rerank", "direct_load_skip", map[string]interface{}{
+				"chunk_id": result.ID,
+			})
+			continue
+		}
 		// 合并Content和ImageInfo的文本内容
 		passage := getEnrichedPassage(ctx, result)
 		passages = append(passages, passage)
+		candidatesToRerank = append(candidatesToRerank, result)
 	}
 
-	// Single rerank call with RewriteQuery, use threshold degradation if no results
-	originalThreshold := chatManage.RerankThreshold
-	rerankResp := p.rerank(ctx, chatManage, rerankModel, chatManage.RewriteQuery, passages)
+	pipelineInfo(ctx, "Rerank", "build_passages", map[string]interface{}{
+		"total_cnt":     len(chatManage.SearchResult),
+		"candidate_cnt": len(candidatesToRerank),
+		"direct_cnt":    len(directLoadResults),
+	})
 
-	// If no results and threshold is high enough, try with lower threshold
-	if len(rerankResp) == 0 && originalThreshold > 0.3 {
-		degradedThreshold := originalThreshold * 0.7
-		if degradedThreshold < 0.3 {
-			degradedThreshold = 0.3
+	var rerankResp []rerank.RankResult
+
+	// Only call rerank model if there are candidates
+	if len(candidatesToRerank) > 0 {
+		// Single rerank call with RewriteQuery, use threshold degradation if no results
+		originalThreshold := chatManage.RerankThreshold
+		rerankResp = p.rerank(ctx, chatManage, rerankModel, chatManage.RewriteQuery, passages, candidatesToRerank)
+
+		// If no results and threshold is high enough, try with lower threshold
+		if len(rerankResp) == 0 && originalThreshold > 0.3 {
+			degradedThreshold := originalThreshold * 0.7
+			if degradedThreshold < 0.3 {
+				degradedThreshold = 0.3
+			}
+			pipelineInfo(ctx, "Rerank", "threshold_degrade", map[string]interface{}{
+				"original": originalThreshold,
+				"degraded": degradedThreshold,
+			})
+			chatManage.RerankThreshold = degradedThreshold
+			rerankResp = p.rerank(ctx, chatManage, rerankModel, chatManage.RewriteQuery, passages, candidatesToRerank)
+			// Restore original threshold
+			chatManage.RerankThreshold = originalThreshold
 		}
-		pipelineInfo(ctx, "Rerank", "threshold_degrade", map[string]interface{}{
-			"original": originalThreshold,
-			"degraded": degradedThreshold,
-		})
-		chatManage.RerankThreshold = degradedThreshold
-		rerankResp = p.rerank(ctx, chatManage, rerankModel, chatManage.RewriteQuery, passages)
-		// Restore original threshold
-		chatManage.RerankThreshold = originalThreshold
 	}
 
 	pipelineInfo(ctx, "Rerank", "model_response", map[string]interface{}{
@@ -114,9 +133,14 @@ func (p *PluginRerank) OnEvent(ctx context.Context,
 	for i := range chatManage.SearchResult {
 		chatManage.SearchResult[i].Metadata = ensureMetadata(chatManage.SearchResult[i].Metadata)
 	}
-	reranked := make([]*types.SearchResult, 0, len(rerankResp))
+	reranked := make([]*types.SearchResult, 0, len(rerankResp)+len(directLoadResults))
+
+	// Process reranked results
 	for _, rr := range rerankResp {
-		sr := chatManage.SearchResult[rr.Index]
+		if rr.Index >= len(candidatesToRerank) {
+			continue
+		}
+		sr := candidatesToRerank[rr.Index]
 		base := sr.Score
 		sr.Metadata["base_score"] = fmt.Sprintf("%.4f", base)
 		modelScore := rr.RelevanceScore
@@ -130,6 +154,23 @@ func (p *PluginRerank) OnEvent(ctx context.Context,
 		})
 		reranked = append(reranked, sr)
 	}
+
+	// Process direct load results (bypass rerank model, assume high relevance)
+	for _, sr := range directLoadResults {
+		base := sr.Score
+		sr.Metadata["base_score"] = fmt.Sprintf("%.4f", base)
+		// Assign high model score for direct load items
+		modelScore := 1.0
+		sr.Score = compositeScore(sr, modelScore, base)
+		pipelineInfo(ctx, "Rerank", "composite_calc_direct", map[string]interface{}{
+			"chunk_id":    sr.ID,
+			"base_score":  fmt.Sprintf("%.4f", base),
+			"model_score": fmt.Sprintf("%.4f", modelScore),
+			"final_score": fmt.Sprintf("%.4f", sr.Score),
+			"match_type":  sr.MatchType,
+		})
+		reranked = append(reranked, sr)
+	}
 	final := applyMMR(ctx, reranked, chatManage, min(len(reranked), max(1, chatManage.RerankTopK)), 0.7)
 	chatManage.RerankResult = final
 
@@ -160,6 +201,7 @@ func (p *PluginRerank) OnEvent(ctx context.Context,
 // rerank performs the actual reranking operation with given query and passages
 func (p *PluginRerank) rerank(ctx context.Context,
 	chatManage *types.ChatManage, rerankModel rerank.Reranker, query string, passages []string,
+	candidates []*types.SearchResult,
 ) []rerank.RankResult {
 	pipelineInfo(ctx, "Rerank", "model_call", map[string]interface{}{
 		"query_variant": query,
@@ -179,21 +221,26 @@ func (p *PluginRerank) rerank(ctx context.Context,
 		"threshold": chatManage.RerankThreshold,
 	})
 	for i := range min(5, len(rerankResp)) {
-		pipelineInfo(ctx, "Rerank", "top_score", map[string]interface{}{
-			"rank":       i + 1,
-			"score":      rerankResp[i].RelevanceScore,
-			"chunk_id":   chatManage.SearchResult[rerankResp[i].Index].ID,
-			"match_type": chatManage.SearchResult[rerankResp[i].Index].MatchType,
-			"chunk_type": chatManage.SearchResult[rerankResp[i].Index].ChunkType,
-			"content":    chatManage.SearchResult[rerankResp[i].Index].Content,
-		})
+		if rerankResp[i].Index < len(candidates) {
+			pipelineInfo(ctx, "Rerank", "top_score", map[string]interface{}{
+				"rank":       i + 1,
+				"score":      rerankResp[i].RelevanceScore,
+				"chunk_id":   candidates[rerankResp[i].Index].ID,
+				"match_type": candidates[rerankResp[i].Index].MatchType,
+				"chunk_type": candidates[rerankResp[i].Index].ChunkType,
+				"content":    candidates[rerankResp[i].Index].Content,
+			})
+		}
 	}
 
 	// Filter results based on threshold with special handling for history matches
 	rankFilter := []rerank.RankResult{}
 	for _, result := range rerankResp {
+		if result.Index >= len(candidates) {
+			continue
+		}
 		th := chatManage.RerankThreshold
-		matchType := chatManage.SearchResult[result.Index].MatchType
+		matchType := candidates[result.Index].MatchType
 		if matchType == types.MatchTypeHistory {
 			th = math.Max(th-0.1, 0.5) // Lower threshold for history matches
 		}
diff --git a/internal/application/service/chat_pipline/search.go b/internal/application/service/chat_pipline/search.go
index 2d249d8a1..75c0402c3 100644
--- a/internal/application/service/chat_pipline/search.go
+++ b/internal/application/service/chat_pipline/search.go
@@ -19,6 +19,7 @@ import (
 type PluginSearch struct {
 	knowledgeBaseService interfaces.KnowledgeBaseService
 	knowledgeService     interfaces.KnowledgeService
+	chunkService         interfaces.ChunkService
 	config               *config.Config
 	webSearchService     interfaces.WebSearchService
 	tenantService        interfaces.TenantService
@@ -28,6 +29,7 @@ type PluginSearch struct {
 func NewPluginSearch(eventManager *EventManager,
 	knowledgeBaseService interfaces.KnowledgeBaseService,
 	knowledgeService interfaces.KnowledgeService,
+	chunkService interfaces.ChunkService,
 	config *config.Config,
 	webSearchService interfaces.WebSearchService,
 	tenantService interfaces.TenantService,
@@ -36,6 +38,7 @@ func NewPluginSearch(eventManager *EventManager,
 	res := &PluginSearch{
 		knowledgeBaseService: knowledgeBaseService,
 		knowledgeService:     knowledgeService,
+		chunkService:         chunkService,
 		config:               config,
 		webSearchService:     webSearchService,
 		tenantService:        tenantService,
@@ -54,35 +57,25 @@ func (p *PluginSearch) ActivationEvents() []types.EventType {
 func (p *PluginSearch) OnEvent(ctx context.Context,
 	eventType types.EventType, chatManage *types.ChatManage, next func() *PluginError,
 ) *PluginError {
-	// Get knowledge base IDs list
-	knowledgeBaseIDs := chatManage.KnowledgeBaseIDs
-	if len(knowledgeBaseIDs) == 0 && chatManage.KnowledgeBaseID != "" {
-		// Fall back to single knowledge base
-		knowledgeBaseIDs = []string{chatManage.KnowledgeBaseID}
-		pipelineInfo(ctx, "Search", "fallback_kb", map[string]interface{}{
-			"session_id": chatManage.SessionID,
-			"kb_id":      chatManage.KnowledgeBaseID,
-		})
-	}
-
-	if len(knowledgeBaseIDs) == 0 {
+	// Check if we have search targets
+	if len(chatManage.SearchTargets) == 0 && len(chatManage.KnowledgeBaseIDs) == 0 && len(chatManage.KnowledgeIDs) == 0 {
 		pipelineError(ctx, "Search", "kb_not_found", map[string]interface{}{
 			"session_id": chatManage.SessionID,
 		})
-		return ErrSearch.WithError(nil)
+		return nil
 	}
 
 	pipelineInfo(ctx, "Search", "input", map[string]interface{}{
-		"session_id":    chatManage.SessionID,
-		"rewrite_query": chatManage.RewriteQuery,
-		"kb_ids":        strings.Join(knowledgeBaseIDs, ","),
-		"tenant_id":     chatManage.TenantID,
-		"web_enabled":   chatManage.WebSearchEnabled,
+		"session_id":     chatManage.SessionID,
+		"rewrite_query":  chatManage.RewriteQuery,
+		"search_targets": len(chatManage.SearchTargets),
+		"tenant_id":      chatManage.TenantID,
+		"web_enabled":    chatManage.WebSearchEnabled,
 	})
 
 	// Run KB search and web search concurrently
 	pipelineInfo(ctx, "Search", "plan", map[string]interface{}{
-		"kb_count":          len(knowledgeBaseIDs),
+		"search_targets":    len(chatManage.SearchTargets),
 		"embedding_top_k":   chatManage.EmbeddingTopK,
 		"vector_threshold":  chatManage.VectorThreshold,
 		"keyword_threshold": chatManage.KeywordThreshold,
@@ -92,10 +85,10 @@ func (p *PluginSearch) OnEvent(ctx context.Context,
 	allResults := make([]*types.SearchResult, 0)
 
 	wg.Add(2)
-	// Goroutine 1: Knowledge base search (rewrite + processed)
+	// Goroutine 1: Knowledge base search using SearchTargets
 	go func() {
 		defer wg.Done()
-		kbResults := p.searchKnowledgeBases(ctx, knowledgeBaseIDs, chatManage)
+		kbResults := p.searchByTargets(ctx, chatManage)
 		if len(kbResults) > 0 {
 			mu.Lock()
 			allResults = append(allResults, kbResults...)
@@ -141,11 +134,11 @@ func (p *PluginSearch) OnEvent(ctx context.Context,
 			})
 			expTopK := max(chatManage.EmbeddingTopK*2, chatManage.RerankTopK*2)
 			expKwTh := chatManage.KeywordThreshold * 0.8
-			// Concurrent expansion retrieval across queries and KBs
+			// Concurrent expansion retrieval across queries and search targets
 			expResults := make([]*types.SearchResult, 0, expTopK*len(expansions))
 			var muExp sync.Mutex
 			var wgExp sync.WaitGroup
-			jobs := len(expansions) * len(knowledgeBaseIDs)
+			jobs := len(expansions) * len(chatManage.SearchTargets)
 			capSem := 16
 			if jobs < capSem {
 				capSem = jobs
@@ -159,9 +152,9 @@ func (p *PluginSearch) OnEvent(ctx context.Context,
 				"cap":  capSem,
 			})
 			for _, q := range expansions {
-				for _, kbID := range knowledgeBaseIDs {
+				for _, target := range chatManage.SearchTargets {
 					wgExp.Add(1)
-					go func(q string, kbID string) {
+					go func(q string, t *types.SearchTarget) {
 						defer wgExp.Done()
 						sem <- struct{}{}
 						defer func() { <-sem }()
@@ -173,17 +166,21 @@ func (p *PluginSearch) OnEvent(ctx context.Context,
 							DisableVectorMatch:   true,
 							DisableKeywordsMatch: false,
 						}
-						res, err := p.knowledgeBaseService.HybridSearch(ctx, kbID, paramsExp)
+						// Apply knowledge ID filter if this is a partial KB search
+						if t.Type == types.SearchTargetTypeKnowledge {
+							paramsExp.KnowledgeIDs = t.KnowledgeIDs
+						}
+						res, err := p.knowledgeBaseService.HybridSearch(ctx, t.KnowledgeBaseID, paramsExp)
 						if err != nil {
 							pipelineWarn(ctx, "Search", "expansion_error", map[string]interface{}{
-								"kb_id": kbID,
+								"kb_id": t.KnowledgeBaseID,
 								"error": err.Error(),
 							})
 							return
 						}
 						if len(res) > 0 {
 							pipelineInfo(ctx, "Search", "expansion_hits", map[string]interface{}{
-								"kb_id": kbID,
+								"kb_id": t.KnowledgeBaseID,
 								"query": q,
 								"hits":  len(res),
 							})
@@ -191,7 +188,7 @@ func (p *PluginSearch) OnEvent(ctx context.Context,
 							expResults = append(expResults, res...)
 							muExp.Unlock()
 						}
-					}(q, kbID)
+					}(q, target)
 				}
 			}
 			wgExp.Wait()
@@ -308,46 +305,89 @@ func buildContentSignature(content string) string {
 	return searchutil.BuildContentSignature(content)
 }
 
-// searchKnowledgeBases performs KB searches across KB IDs using RewriteQuery only
-func (p *PluginSearch) searchKnowledgeBases(
+// searchByTargets performs KB searches using pre-computed SearchTargets
+// This is the main search method that uses the unified search targets
+func (p *PluginSearch) searchByTargets(
 	ctx context.Context,
-	knowledgeBaseIDs []string,
 	chatManage *types.ChatManage,
 ) []*types.SearchResult {
-	// Build params for rewrite query
-	baseParams := types.SearchParams{
-		QueryText:        strings.TrimSpace(chatManage.RewriteQuery),
-		VectorThreshold:  chatManage.VectorThreshold,
-		KeywordThreshold: chatManage.KeywordThreshold,
-		MatchCount:       chatManage.EmbeddingTopK,
+	if len(chatManage.SearchTargets) == 0 {
+		return nil
 	}
 
 	var wg sync.WaitGroup
 	var mu sync.Mutex
 	var results []*types.SearchResult
 
-	// Search with rewrite query only (removed duplicate ProcessedQuery search)
-	for _, kbID := range knowledgeBaseIDs {
+	// Search each target concurrently
+	for _, target := range chatManage.SearchTargets {
 		wg.Add(1)
-		go func(knowledgeBaseID string) {
+		go func(t *types.SearchTarget) {
 			defer wg.Done()
-			res, err := p.knowledgeBaseService.HybridSearch(ctx, knowledgeBaseID, baseParams)
+
+			// List of knowledge IDs to perform vector search on
+			// Default to all IDs in the target
+			searchKnowledgeIDs := t.KnowledgeIDs
+
+			// Try direct loading for specific knowledge targets
+			if t.Type == types.SearchTargetTypeKnowledge {
+				directResults, skippedIDs := p.tryDirectChunkLoading(ctx, chatManage.TenantID, t.KnowledgeIDs)
+				
+				if len(directResults) > 0 {
+					pipelineInfo(ctx, "Search", "direct_load", map[string]interface{}{
+						"kb_id":        t.KnowledgeBaseID,
+						"loaded_count": len(directResults),
+						"skipped_ids":  len(skippedIDs),
+					})
+					mu.Lock()
+					results = append(results, directResults...)
+					mu.Unlock()
+				}
+
+				// If all files were loaded directly, we don't need to search anything
+				if len(skippedIDs) == 0 && len(t.KnowledgeIDs) > 0 {
+					return
+				}
+
+				// Otherwise, only search the files that were skipped (too large)
+				searchKnowledgeIDs = skippedIDs
+			}
+
+			// If no IDs left to search (and we are in Knowledge mode), we are done
+			if t.Type == types.SearchTargetTypeKnowledge && len(searchKnowledgeIDs) == 0 {
+				return
+			}
+
+			// Build params for rewrite query
+			params := types.SearchParams{
+				QueryText:        strings.TrimSpace(chatManage.RewriteQuery),
+				VectorThreshold:  chatManage.VectorThreshold,
+				KeywordThreshold: chatManage.KeywordThreshold,
+				MatchCount:       chatManage.EmbeddingTopK,
+			}
+			// Apply knowledge ID filter if this is a partial KB search
+			if t.Type == types.SearchTargetTypeKnowledge {
+				params.KnowledgeIDs = searchKnowledgeIDs
+			}
+			res, err := p.knowledgeBaseService.HybridSearch(ctx, t.KnowledgeBaseID, params)
 			if err != nil {
 				pipelineWarn(ctx, "Search", "kb_search_error", map[string]interface{}{
-					"kb_id": knowledgeBaseID,
-					"query": baseParams.QueryText,
-					"error": err.Error(),
+					"kb_id":       t.KnowledgeBaseID,
+					"target_type": t.Type,
+					"query":       params.QueryText,
+					"error":       err.Error(),
 				})
 				return
 			}
 			pipelineInfo(ctx, "Search", "kb_result", map[string]interface{}{
-				"kb_id":     knowledgeBaseID,
-				"hit_count": len(res),
+				"kb_id":       t.KnowledgeBaseID,
+				"target_type": t.Type,
+				"hit_count":   len(res),
 			})
 			mu.Lock()
 			results = append(results, res...)
 			mu.Unlock()
-		}(kbID)
+		}(target)
 	}
 
 	wg.Wait()
@@ -358,6 +398,93 @@ func (p *PluginSearch) searchKnowledgeBases(
 	return results
 }
 
+// tryDirectChunkLoading attempts to load chunks for given knowledge IDs directly
+// Returns loaded results and a list of knowledge IDs that were skipped (e.g. due to size limits)
+func (p *PluginSearch) tryDirectChunkLoading(ctx context.Context, tenantID uint64, knowledgeIDs []string) ([]*types.SearchResult, []string) {
+	if len(knowledgeIDs) == 0 {
+		return nil, nil
+	}
+
+	// Limit direct loading to avoid OOM or context overflow
+	// 50 chunks * ~500 chars/chunk ~= 25k chars
+	const maxTotalChunks = 50
+
+	var allChunks []*types.Chunk
+	var skippedIDs []string
+	loadedKnowledgeIDs := make(map[string]bool)
+
+	for _, kid := range knowledgeIDs {
+		// Optimization: Check chunk count first if possible?
+		chunks, err := p.chunkService.ListChunksByKnowledgeID(ctx, kid)
+		if err != nil {
+			logger.Warnf(ctx, "DirectLoad: Failed to list chunks for knowledge %s: %v", kid, err)
+			skippedIDs = append(skippedIDs, kid)
+			continue
+		}
+
+		if len(allChunks)+len(chunks) > maxTotalChunks {
+			logger.Infof(ctx, "DirectLoad: Skipped knowledge %s due to size limit (%d + %d > %d)",
+				kid, len(allChunks), len(chunks), maxTotalChunks)
+			skippedIDs = append(skippedIDs, kid)
+			continue
+		}
+		allChunks = append(allChunks, chunks...)
+		loadedKnowledgeIDs[kid] = true
+	}
+
+	if len(allChunks) == 0 {
+		return nil, skippedIDs
+	}
+
+	// Fetch Knowledge metadata
+	var uniqueKIDs []string
+	for kid := range loadedKnowledgeIDs {
+		uniqueKIDs = append(uniqueKIDs, kid)
+	}
+
+	knowledgeMap := make(map[string]*types.Knowledge)
+	if len(uniqueKIDs) > 0 {
+		knowledges, err := p.knowledgeService.GetKnowledgeBatch(ctx, tenantID, uniqueKIDs)
+		if err != nil {
+			logger.Warnf(ctx, "DirectLoad: Failed to fetch knowledge batch: %v", err)
+			// Continue without metadata
+		} else {
+			for _, k := range knowledges {
+				knowledgeMap[k.ID] = k
+			}
+		}
+	}
+
+	var results []*types.SearchResult
+	for _, chunk := range allChunks {
+		res := &types.SearchResult{
+			ID:            chunk.ID,
+			Content:       chunk.Content,
+			Score:         1.0, // Maximum score for direct matches
+			KnowledgeID:   chunk.KnowledgeID,
+			ChunkIndex:    chunk.ChunkIndex,
+			MatchType:     types.MatchTypeDirectLoad,
+			ChunkType:     string(chunk.ChunkType),
+			ParentChunkID: chunk.ParentChunkID,
+			ImageInfo:     chunk.ImageInfo,
+			ChunkMetadata: chunk.Metadata,
+			StartAt:       chunk.StartAt,
+			EndAt:         chunk.EndAt,
+		}
+
+		if k, ok := knowledgeMap[chunk.KnowledgeID]; ok {
+			res.KnowledgeTitle = k.Title
+			res.KnowledgeFilename = k.FileName
+			res.KnowledgeSource = k.Source
+			res.Metadata = k.GetMetadata()
+		}
+
+		results = append(results, res)
+	}
+
+	return results, skippedIDs
+}
+
 // searchWebIfEnabled executes web search when enabled and returns converted results
 func (p *PluginSearch) searchWebIfEnabled(ctx context.Context, chatManage *types.ChatManage) []*types.SearchResult {
 	if !chatManage.WebSearchEnabled || p.webSearchService == nil || p.tenantService == nil || chatManage.TenantID <= 0 {
diff --git a/internal/application/service/chat_pipline/search_entity.go b/internal/application/service/chat_pipline/search_entity.go
index 94cfa4548..82569e40b 100644
--- a/internal/application/service/chat_pipline/search_entity.go
+++ b/internal/application/service/chat_pipline/search_entity.go
@@ -47,50 +47,81 @@ func (p *PluginSearchEntity) OnEvent(ctx context.Context,
 		return next()
 	}
 
-	// Get knowledge base IDs list
-	knowledgeBaseIDs := chatManage.KnowledgeBaseIDs
-	if len(knowledgeBaseIDs) == 0 && chatManage.KnowledgeBaseID != "" {
-		knowledgeBaseIDs = []string{chatManage.KnowledgeBaseID}
-		logger.Infof(ctx, "No KnowledgeBaseIDs provided, falling back to single KB: %s", chatManage.KnowledgeBaseID)
-	}
+	// Use EntityKBIDs (knowledge bases with ExtractConfig enabled)
+	knowledgeBaseIDs := chatManage.EntityKBIDs
+	// Use EntityKnowledge (KnowledgeID -> KnowledgeBaseID mapping for graph-enabled files)
+	entityKnowledge := chatManage.EntityKnowledge
 
-	if len(knowledgeBaseIDs) == 0 {
-		logger.Warnf(ctx, "No knowledge base IDs available for entity search")
+	if len(knowledgeBaseIDs) == 0 && len(entityKnowledge) == 0 {
+		logger.Warnf(ctx, "No knowledge base IDs or knowledge IDs with ExtractConfig enabled for entity search")
 		return next()
 	}
 
-	logger.Infof(ctx, "Searching entities across %d knowledge base(s): %v", len(knowledgeBaseIDs), knowledgeBaseIDs)
-
-	// Parallel search across multiple knowledge bases
+	// Parallel search across multiple knowledge bases and individual files
 	var wg sync.WaitGroup
 	var mu sync.Mutex
 	var allNodes []*types.GraphNode
 	var allRelations []*types.GraphRelation
 
-	for _, kbID := range knowledgeBaseIDs {
-		wg.Add(1)
-		go func(knowledgeBaseID string) {
-			defer wg.Done()
+	// If specific KnowledgeIDs are provided, search by individual files
+	if len(entityKnowledge) > 0 {
+		logger.Infof(ctx, "Searching entities across %d knowledge file(s)", len(entityKnowledge))
+		for knowledgeID, kbID := range entityKnowledge {
+			wg.Add(1)
+			go func(knowledgeBaseID, knowledgeID string) {
+				defer wg.Done()
 
-			graph, err := p.graphRepo.SearchNode(ctx, types.NameSpace{KnowledgeBase: knowledgeBaseID}, entity)
-			if err != nil {
-				logger.Errorf(ctx, "Failed to search entity in KB %s: %v", knowledgeBaseID, err)
-				return
-			}
+				graph, err := p.graphRepo.SearchNode(ctx, types.NameSpace{
+					KnowledgeBase: knowledgeBaseID,
+					Knowledge:     knowledgeID,
+				}, entity)
+				if err != nil {
+					logger.Errorf(ctx, "Failed to search entity in Knowledge %s: %v", knowledgeID, err)
+					return
+				}
 
-			logger.Infof(
-				ctx,
-				"KB %s entity search result count: %d nodes, %d relations",
-				knowledgeBaseID,
-				len(graph.Node),
-				len(graph.Relation),
-			)
+				logger.Infof(
+					ctx,
+					"Knowledge %s entity search result count: %d nodes, %d relations",
+					knowledgeID,
+					len(graph.Node),
+					len(graph.Relation),
+				)
 
-			mu.Lock()
-			allNodes = append(allNodes, graph.Node...)
-			allRelations = append(allRelations, graph.Relation...)
-			mu.Unlock()
-		}(kbID)
+				mu.Lock()
+				allNodes = append(allNodes, graph.Node...)
+				allRelations = append(allRelations, graph.Relation...)
+				mu.Unlock()
+			}(kbID, knowledgeID)
+		}
+	} else {
+		// Otherwise, search by knowledge base
+		logger.Infof(ctx, "Searching entities across %d knowledge base(s): %v", len(knowledgeBaseIDs), knowledgeBaseIDs)
+		for _, kbID := range knowledgeBaseIDs {
+			wg.Add(1)
+			go func(knowledgeBaseID string) {
+				defer wg.Done()
+
+				graph, err := p.graphRepo.SearchNode(ctx, types.NameSpace{KnowledgeBase: knowledgeBaseID}, entity)
+				if err != nil {
+					logger.Errorf(ctx, "Failed to search entity in KB %s: %v", knowledgeBaseID, err)
+					return
+				}
+
+				logger.Infof(
+					ctx,
+					"KB %s entity search result count: %d nodes, %d relations",
+					knowledgeBaseID,
+					len(graph.Node),
+					len(graph.Relation),
+				)
+
+				mu.Lock()
+				allNodes = append(allNodes, graph.Node...)
+				allRelations = append(allRelations, graph.Relation...)
+				mu.Unlock()
+			}(kbID)
+		}
 	}
 
 	wg.Wait()
diff --git a/internal/application/service/chat_pipline/search_parallel.go b/internal/application/service/chat_pipline/search_parallel.go
index 6148016dc..d0f5fa03d 100644
--- a/internal/application/service/chat_pipline/search_parallel.go
+++ b/internal/application/service/chat_pipline/search_parallel.go
@@ -35,6 +35,7 @@ func NewPluginSearchParallel(
 	eventManager *EventManager,
 	knowledgeBaseService interfaces.KnowledgeBaseService,
 	knowledgeService interfaces.KnowledgeService,
+	chunkService interfaces.ChunkService,
 	config *config.Config,
 	webSearchService interfaces.WebSearchService,
 	tenantService interfaces.TenantService,
@@ -47,6 +48,7 @@ func NewPluginSearchParallel(
 	searchPlugin := &PluginSearch{
 		knowledgeBaseService: knowledgeBaseService,
 		knowledgeService:     knowledgeService,
+		chunkService:         chunkService,
 		config:               config,
 		webSearchService:     webSearchService,
 		tenantService:        tenantService,
diff --git a/internal/application/service/evaluation.go b/internal/application/service/evaluation.go
index a5b60270f..b71ea63d2 100644
--- a/internal/application/service/evaluation.go
+++ b/internal/application/service/evaluation.go
@@ -266,7 +266,6 @@ func (e *EvaluationService) Evaluation(ctx context.Context,
 			StartTime: time.Now(),
 		},
 		Params: &types.ChatManage{
-			KnowledgeBaseID:  knowledgeBaseID,
 			VectorThreshold:  e.config.Conversation.VectorThreshold,
 			KeywordThreshold: e.config.Conversation.KeywordThreshold,
 			EmbeddingTopK:    e.config.Conversation.EmbeddingTopK,
@@ -311,7 +310,7 @@ func (e *EvaluationService) Evaluation(ctx context.Context,
 		logger.Info(newCtx, "Evaluation task status set to running")
 
 		// Execute actual evaluation
-		if err := e.EvalDataset(newCtx, detail); err != nil {
+		if err := e.EvalDataset(newCtx, detail, knowledgeBaseID); err != nil {
 			detail.Task.Status = types.EvaluationStatueFailed
 			detail.Task.ErrMsg = err.Error()
 			logger.Errorf(newCtx, "Evaluation task failed: %v, task ID: %s", err, taskID)
@@ -329,7 +328,7 @@ func (e *EvaluationService) Evaluation(ctx context.Context,
 
 // EvalDataset performs the actual evaluation of a dataset
 // Processes each QA pair in parallel and records metrics
-func (e *EvaluationService) EvalDataset(ctx context.Context, detail *types.EvaluationDetail) error {
+func (e *EvaluationService) EvalDataset(ctx context.Context, detail *types.EvaluationDetail, knowledgeBaseID string) error {
 	logger.Info(ctx, "Start evaluating dataset")
 	logger.Infof(ctx, "Task ID: %s, Dataset ID: %s", detail.Task.ID, detail.Task.DatasetID)
 
@@ -352,7 +351,7 @@ func (e *EvaluationService) EvalDataset(ctx context.Context, detail *types.Evalu
 	logger.Infof(ctx, "Creating knowledge from %d passages", len(passages))
 
 	// Create knowledge base from passages
-	knowledge, err := e.knowledgeService.CreateKnowledgeFromPassage(ctx, detail.Params.KnowledgeBaseID, passages)
+	knowledge, err := e.knowledgeService.CreateKnowledgeFromPassage(ctx, knowledgeBaseID, passages)
 	if err != nil {
 		logger.Errorf(ctx, "Failed to create knowledge from passages: %v", err)
 		return err
@@ -366,12 +365,12 @@ func (e *EvaluationService) EvalDataset(ctx context.Context, detail *types.Evalu
 			logger.Errorf(ctx, "Failed to delete knowledge: %v, knowledge ID: %s", err, knowledge.ID)
 		}
 
-		logger.Infof(ctx, "Cleaning up resources - deleting knowledge base: %s", detail.Params.KnowledgeBaseID)
-		if err := e.knowledgeBaseService.DeleteKnowledgeBase(ctx, detail.Params.KnowledgeBaseID); err != nil {
+		logger.Infof(ctx, "Cleaning up resources - deleting knowledge base: %s", knowledgeBaseID)
+		if err := e.knowledgeBaseService.DeleteKnowledgeBase(ctx, knowledgeBaseID); err != nil {
 			logger.Errorf(
 				ctx,
 				"Failed to delete knowledge base: %v, knowledge base ID: %s",
-				err, detail.Params.KnowledgeBaseID,
+				err, knowledgeBaseID,
 			)
 		}
 	}()
diff --git a/internal/application/service/knowledge.go b/internal/application/service/knowledge.go
index befb20fd2..26aeb4eef 100644
--- a/internal/application/service/knowledge.go
+++ b/internal/application/service/knowledge.go
@@ -5766,3 +5766,13 @@ func (s *knowledgeService) getOrCreateTagInTarget(
 	logger.Infof(ctx, "Created tag %s (ID: %s) in target KB %s", newTag.Name, newTag.ID, dstKnowledgeBaseID)
 	return newTag.ID
 }
+
+// SearchKnowledge searches knowledge items by keyword across the tenant
+func (s *knowledgeService) SearchKnowledge(ctx context.Context, keyword string, offset, limit int) ([]*types.Knowledge, bool, error) {
+	tenantID, ok := ctx.Value(types.TenantIDContextKey).(uint64)
+	if !ok {
+		return nil, false, werrors.NewUnauthorizedError("Tenant ID not found in context")
+	}
+	return s.repo.SearchKnowledge(ctx, tenantID, keyword, offset, limit)
+}
+
diff --git a/internal/application/service/knowledgebase.go b/internal/application/service/knowledgebase.go
index d35bdde97..a02be888c 100644
--- a/internal/application/service/knowledgebase.go
+++ b/internal/application/service/knowledgebase.go
@@ -491,6 +491,7 @@ func (s *knowledgeBaseService) HybridSearch(ctx context.Context,
 			TopK:             matchCount,
 			Threshold:        params.VectorThreshold,
 			RetrieverType:    types.VectorRetrieverType,
+			KnowledgeIDs:     params.KnowledgeIDs,
 		}
 
 		// For FAQ knowledge base, use FAQ index
@@ -512,6 +513,7 @@ func (s *knowledgeBaseService) HybridSearch(ctx context.Context,
 			TopK:             matchCount,
 			Threshold:        params.KeywordThreshold,
 			RetrieverType:    types.KeywordsRetrieverType,
+			KnowledgeIDs:     params.KnowledgeIDs,
 		})
 		logger.Info(ctx, "Keyword retrieval parameters setup completed")
 	}
diff --git a/internal/application/service/session.go b/internal/application/service/session.go
index 949ad8c13..c277ed57c 100644
--- a/internal/application/service/session.go
+++ b/internal/application/service/session.go
@@ -43,6 +43,7 @@ type sessionService struct {
 	agentService         interfaces.AgentService         // Service for agent operations
 	sessionStorage       llmcontext.ContextStorage       // Session storage
 	knowledgeService     interfaces.KnowledgeService     // Service for knowledge operations
+	chunkService         interfaces.ChunkService         // Service for chunk operations
 	redisClient          *redis.Client                   // Redis client for temp KB state
 }
 
@@ -52,6 +53,7 @@ func NewSessionService(cfg *config.Config,
 	messageRepo interfaces.MessageRepository,
 	knowledgeBaseService interfaces.KnowledgeBaseService,
 	knowledgeService interfaces.KnowledgeService,
+	chunkService interfaces.ChunkService,
 	modelService interfaces.ModelService,
 	tenantService interfaces.TenantService,
 	eventManager *chatpipline.EventManager,
@@ -65,6 +67,7 @@ func NewSessionService(cfg *config.Config,
 		messageRepo:          messageRepo,
 		knowledgeBaseService: knowledgeBaseService,
 		knowledgeService:     knowledgeService,
+		chunkService:         chunkService,
 		modelService:         modelService,
 		tenantService:        tenantService,
 		eventManager:         eventManager,
@@ -394,6 +397,7 @@ func (s *sessionService) KnowledgeQA(
 	session *types.Session,
 	query string,
 	knowledgeBaseIDs []string,
+	knowledgeIDs []string,
 	assistantMessageID string,
 	summaryModelID string,
 	webSearchEnabled bool,
@@ -414,14 +418,13 @@ func (s *sessionService) KnowledgeQA(
 			logger.Infof(ctx, "No knowledge base IDs provided, using session default: %s", session.KnowledgeBaseID)
 		} else {
 			logger.Warnf(ctx, "Session has no associated knowledge base, session ID: %s", session.ID)
-			return errors.New("session has no knowledge base")
 		}
 	}
 
 	logger.Infof(ctx, "Using knowledge bases: %v", knowledgeBaseIDs)
 
 	// Determine chat model ID: prioritize request's summaryModelID, then Remote models
-	chatModelID, err := s.selectChatModelIDWithOverride(ctx, session, knowledgeBaseIDs, summaryModelID)
+	chatModelID, err := s.selectChatModelIDWithOverride(ctx, session, knowledgeBaseIDs, knowledgeIDs, summaryModelID)
 	if err != nil {
 		return err
 	}
@@ -511,20 +514,29 @@ func (s *sessionService) KnowledgeQA(
 		logger.Infof(ctx, "Fallback strategy not set, using default: %v", fallbackStrategy)
 	}
 
+	// Build unified search targets (computed once, used throughout pipeline)
+	searchTargets, err := s.buildSearchTargets(ctx, session.TenantID, knowledgeBaseIDs, knowledgeIDs)
+	if err != nil {
+		logger.Warnf(ctx, "Failed to build search targets: %v", err)
+	}
+
 	// Create chat management object with session settings
 	logger.Infof(
 		ctx,
-		"Creating chat manage object, knowledge base IDs: %v, chat model ID: %s",
+		"Creating chat manage object, knowledge base IDs: %v, knowledge IDs: %v, chat model ID: %s, search targets: %d",
 		knowledgeBaseIDs,
+		knowledgeIDs,
 		chatModelID,
+		len(searchTargets),
 	)
 	chatManage := &types.ChatManage{
 		Query:                query,
 		RewriteQuery:         query,
 		SessionID:            session.ID,
-		MessageID:            assistantMessageID,  // NEW: For event emission in pipeline
-		KnowledgeBaseID:      knowledgeBaseIDs[0], // For backward compatibility, use first KB ID
-		KnowledgeBaseIDs:     knowledgeBaseIDs,    // Multi-KB support
+		MessageID:            assistantMessageID, // NEW: For event emission in pipeline
+		KnowledgeBaseIDs:     knowledgeBaseIDs,   // Multi-KB support
+		KnowledgeIDs:         knowledgeIDs,       // Specific knowledge (file) IDs
+		SearchTargets:        searchTargets,      // Pre-computed search targets
 		VectorThreshold:      vectorThreshold,
 		KeywordThreshold:     keywordThreshold,
 		EmbeddingTopK:        embeddingTopK,
@@ -546,9 +558,22 @@ func (s *sessionService) KnowledgeQA(
 		EnableQueryExpansion: enableQueryExpansion,
 	}
 
+	// Determine pipeline based on knowledge bases availability
+	// If no knowledge bases are selected, use pure chat pipeline
+	var pipeline []types.EventType
+	if len(knowledgeBaseIDs) == 0 && len(knowledgeIDs) == 0 {
+		logger.Info(ctx, "No knowledge bases selected, using chat_stream pipeline")
+		pipeline = types.Pipline["chat_stream"]
+		// For pure chat, UserContent is the Query (since INTO_CHAT_MESSAGE is skipped)
+		chatManage.UserContent = query
+	} else {
+		logger.Info(ctx, "Knowledge bases selected, using rag_stream pipeline")
+		pipeline = types.Pipline["rag_stream"]
+	}
+
 	// Start knowledge QA event processing
-	logger.Info(ctx, "Triggering knowledge base question answering event")
-	err = s.KnowledgeQAByEvent(ctx, chatManage, types.Pipline["rag_stream"])
+	logger.Info(ctx, "Triggering question answering event")
+	err = s.KnowledgeQAByEvent(ctx, chatManage, pipeline)
 	if err != nil {
 		logger.ErrorWithFields(ctx, err, map[string]interface{}{
 			"session_id":        session.ID,
@@ -592,6 +617,7 @@ func (s *sessionService) selectChatModelIDWithOverride(
 	ctx context.Context,
 	session *types.Session,
 	knowledgeBaseIDs []string,
+	knowledgeIDs []string,
 	summaryModelID string,
 ) (string, error) {
 	// First, check if request has summaryModelID override
@@ -612,33 +638,47 @@ func (s *sessionService) selectChatModelIDWithOverride(
 	}
 
 	// If no valid override, use default selection logic
-	return s.selectChatModelID(ctx, session, knowledgeBaseIDs)
+	return s.selectChatModelID(ctx, session, knowledgeBaseIDs, knowledgeIDs)
 }
 
 // selectChatModelID selects the appropriate chat model ID with priority for Remote models
 // Priority order:
 // 1. Session's SummaryModelID if it's a Remote model
-// 2. First knowledge base with a Remote model
+// 2. First knowledge base with a Remote model (from knowledgeBaseIDs or derived from knowledgeIDs)
 // 3. Session's SummaryModelID (if not Remote)
 // 4. First knowledge base's SummaryModelID
 func (s *sessionService) selectChatModelID(
 	ctx context.Context,
 	session *types.Session,
 	knowledgeBaseIDs []string,
+	knowledgeIDs []string,
 ) (string, error) {
+
 	// First, check if session has a SummaryModelID and if it's a Remote model
 	if session.SummaryModelID != "" {
-		model, err := s.modelService.GetModelByID(ctx, session.SummaryModelID)
-		if err == nil && model != nil && model.Source == types.ModelSourceRemote {
-			logger.Infof(ctx, "Using session's Remote summary model: %s", session.SummaryModelID)
-			return session.SummaryModelID, nil
-		} else if err == nil && model != nil {
-			// Session has a model but it's not Remote, we'll check knowledge bases for Remote models
-			logger.Infof(ctx, "Session has summary model %s but it's not Remote, "+
-				"checking knowledge bases for Remote models", session.SummaryModelID)
+		return session.SummaryModelID, nil
+	}
+	// If no knowledge base IDs but have knowledge IDs, derive KB IDs from knowledge IDs
+	if len(knowledgeBaseIDs) == 0 && len(knowledgeIDs) > 0 {
+		tenantID := ctx.Value(types.TenantIDContextKey).(uint64)
+		knowledgeList, err := s.knowledgeService.GetKnowledgeBatch(ctx, tenantID, knowledgeIDs)
+		if err != nil {
+			logger.Warnf(ctx, "Failed to get knowledge batch for model selection: %v", err)
+		} else {
+			// Collect unique KB IDs from knowledge items
+			kbIDSet := make(map[string]bool)
+			for _, k := range knowledgeList {
+				if k != nil && k.KnowledgeBaseID != "" {
+					kbIDSet[k.KnowledgeBaseID] = true
+				}
+			}
+			for kbID := range kbIDSet {
+				knowledgeBaseIDs = append(knowledgeBaseIDs, kbID)
+			}
+			logger.Infof(ctx, "Derived %d knowledge base IDs from %d knowledge IDs for model selection",
+				len(knowledgeBaseIDs), len(knowledgeIDs))
 		}
 	}
-
 	// If no Remote model found from session, check knowledge bases for Remote models
 	if len(knowledgeBaseIDs) > 0 {
 		// Try to find a knowledge base with Remote model
@@ -683,12 +723,79 @@ func (s *sessionService) selectChatModelID(
 		}
 	}
 
+	// No knowledge bases - use session's SummaryModelID if available
+	if session.SummaryModelID != "" {
+		logger.Infof(ctx, "No knowledge bases, using session's summary model: %s", session.SummaryModelID)
+		return session.SummaryModelID, nil
+	}
+
 	logger.Error(ctx, "No chat model ID available")
 	return "", errors.New(
-		"no chat model ID available: session has no SummaryModelID and knowledge bases have no SummaryModelID",
+		"no chat model ID available: session has no SummaryModelID and no knowledge bases configured",
 	)
 }
 
+// buildSearchTargets computes the unified search targets from knowledgeBaseIDs and knowledgeIDs
+// This is called once at the request entry point to avoid repeated queries later in the pipeline
+// Logic:
+//   - For each knowledgeBaseID: create a SearchTargetTypeKnowledgeBase target
+//   - For each knowledgeID: find its knowledgeBaseID, if the KB is already in the list, skip (covered by full KB search)
+//     otherwise create a SearchTargetTypeKnowledge target grouped by KB
+func (s *sessionService) buildSearchTargets(
+	ctx context.Context,
+	tenantID uint64,
+	knowledgeBaseIDs []string,
+	knowledgeIDs []string,
+) (types.SearchTargets, error) {
+	var targets types.SearchTargets
+
+	// Track which KBs are fully searched
+	fullKBSet := make(map[string]bool)
+	for _, kbID := range knowledgeBaseIDs {
+		fullKBSet[kbID] = true
+		targets = append(targets, &types.SearchTarget{
+			Type:            types.SearchTargetTypeKnowledgeBase,
+			KnowledgeBaseID: kbID,
+		})
+	}
+
+	// Process individual knowledge IDs
+	if len(knowledgeIDs) > 0 {
+		knowledgeList, err := s.knowledgeService.GetKnowledgeBatch(ctx, tenantID, knowledgeIDs)
+		if err != nil {
+			logger.Warnf(ctx, "Failed to get knowledge batch for search targets: %v", err)
+			return targets, nil // Return what we have, don't fail
+		}
+
+		// Group knowledge IDs by their KB, excluding those already covered by full KB search
+		kbToKnowledgeIDs := make(map[string][]string)
+		for _, k := range knowledgeList {
+			if k == nil || k.KnowledgeBaseID == "" {
+				continue
+			}
+			// Skip if this KB is already fully searched
+			if fullKBSet[k.KnowledgeBaseID] {
+				continue
+			}
+			kbToKnowledgeIDs[k.KnowledgeBaseID] = append(kbToKnowledgeIDs[k.KnowledgeBaseID], k.ID)
+		}
+
+		// Create SearchTargetTypeKnowledge targets for each KB with specific files
+		for kbID, kidList := range kbToKnowledgeIDs {
+			targets = append(targets, &types.SearchTarget{
+				Type:            types.SearchTargetTypeKnowledge,
+				KnowledgeBaseID: kbID,
+				KnowledgeIDs:    kidList,
+			})
+		}
+	}
+
+	logger.Infof(ctx, "Built %d search targets: %d full KB, %d partial KB",
+		len(targets), len(knowledgeBaseIDs), len(targets)-len(knowledgeBaseIDs))
+
+	return targets, nil
+}
+
 // KnowledgeQAByEvent processes knowledge QA through a series of events in the pipeline
 func (s *sessionService) KnowledgeQAByEvent(ctx context.Context,
 	chatManage *types.ChatManage, eventList []types.EventType,
@@ -697,8 +804,8 @@ func (s *sessionService) KnowledgeQAByEvent(ctx context.Context,
 	defer span.End()
 
 	logger.Info(ctx, "Start processing knowledge base question answering through events")
-	logger.Infof(ctx, "Knowledge base question answering parameters, session ID: %s, knowledge base ID: %s, query: %s",
-		chatManage.SessionID, chatManage.KnowledgeBaseID, chatManage.Query)
+	logger.Infof(ctx, "Knowledge base question answering parameters, session ID: %s,  query: %s",
+		chatManage.SessionID, chatManage.Query)
 
 	// Prepare method list for logging and tracing
 	methods := []string{}
@@ -769,7 +876,6 @@ func (s *sessionService) SearchKnowledge(ctx context.Context,
 	chatManage := &types.ChatManage{
 		Query:               query,
 		RewriteQuery:        query,
-		KnowledgeBaseID:     knowledgeBaseID,
 		VectorThreshold:     s.cfg.Conversation.VectorThreshold,  // Use default configuration
 		KeywordThreshold:    s.cfg.Conversation.KeywordThreshold, // Use default configuration
 		EmbeddingTopK:       s.cfg.Conversation.EmbeddingTopK,    // Use default configuration
@@ -800,10 +906,10 @@ func (s *sessionService) SearchKnowledge(ctx context.Context,
 
 	// Use specific event list, only including retrieval-related events, not LLM summarization
 	searchEvents := []types.EventType{
-		types.CHUNK_SEARCH,  // Vector search
-		types.CHUNK_RERANK,  // Rerank search results
-		types.CHUNK_MERGE,   // Merge search results
-		types.FILTER_TOP_K,  // Filter top K results
+		types.CHUNK_SEARCH, // Vector search
+		types.CHUNK_RERANK, // Rerank search results
+		types.CHUNK_MERGE,  // Merge search results
+		types.FILTER_TOP_K, // Filter top K results
 	}
 
 	ctx, span := tracing.ContextWithSpan(ctx, "SessionService.SearchKnowledge")
@@ -895,13 +1001,14 @@ func (s *sessionService) AgentQA(
 
 	// Create runtime AgentConfig by merging session and tenant configs
 	// Tenant config provides the runtime parameters (MaxIterations, Temperature, Tools, Models)
-	// Session config provides KnowledgeBases
+	// Session config provides KnowledgeBases and KnowledgeIDs
 	agentConfig := &types.AgentConfig{
 		MaxIterations:     tenantInfo.AgentConfig.MaxIterations,
 		ReflectionEnabled: tenantInfo.AgentConfig.ReflectionEnabled,
 		AllowedTools:      tools.DefaultAllowedTools(),
 		Temperature:       tenantInfo.AgentConfig.Temperature,
 		KnowledgeBases:    session.AgentConfig.KnowledgeBases,   // Use session's knowledge bases
+		KnowledgeIDs:      session.AgentConfig.KnowledgeIDs,     // Use session's knowledge IDs (individual documents)
 		WebSearchEnabled:  session.AgentConfig.WebSearchEnabled, // Web search enabled from session config
 	}
 
@@ -919,43 +1026,42 @@ func (s *sessionService) AgentQA(
 
 	logger.Infof(ctx, "Merged agent config from tenant %d and session %s", tenantInfo.ID, sessionID)
 
+	// Log knowledge IDs if present
+	if len(agentConfig.KnowledgeIDs) > 0 {
+		logger.Infof(ctx, "Agent configured with %d individual knowledge ID(s): %v",
+			len(agentConfig.KnowledgeIDs), agentConfig.KnowledgeIDs)
+	}
+
 	// Determine knowledge bases for agent
 	// Priority: Session.AgentConfig.KnowledgeBases > Session.KnowledgeBaseID > All tenant knowledge bases
-	if len(agentConfig.KnowledgeBases) == 0 {
+	// Exception: If KnowledgeIDs are specified, don't auto-add all KBs (let buildSearchTargets handle it)
+	if len(agentConfig.KnowledgeBases) == 0 && len(agentConfig.KnowledgeIDs) == 0 {
 		if session.KnowledgeBaseID != "" {
 			// Use session's knowledge base as fallback
 			agentConfig.KnowledgeBases = []string{session.KnowledgeBaseID}
 			logger.Infof(ctx, "Using session's knowledge base for agent: %s", session.KnowledgeBaseID)
 		} else {
-			// Default to all knowledge bases under the tenant
-			logger.Infof(ctx, "No knowledge bases specified, fetching all knowledge bases for tenant")
-			allKBs, err := s.knowledgeBaseService.ListKnowledgeBases(ctx)
-			if err != nil {
-				logger.Errorf(ctx, "Failed to list knowledge bases for tenant: %v", err)
-				return fmt.Errorf("failed to list knowledge bases: %w", err)
-			}
-
-			if len(allKBs) == 0 {
-				logger.Warnf(ctx, "No knowledge bases available for agent session: %s", sessionID)
-				return errors.New("no knowledge bases available for agent")
-			}
-
-			// Extract knowledge base IDs
-			agentConfig.KnowledgeBases = make([]string, len(allKBs))
-			for i, kb := range allKBs {
-				if kb == nil {
-					continue
-				}
-				agentConfig.KnowledgeBases[i] = kb.ID
-			}
-			logger.Infof(ctx, "Agent defaulting to all %d knowledge base(s) in tenant: %v",
-				len(agentConfig.KnowledgeBases), agentConfig.KnowledgeBases)
+			// Allow running without knowledge bases (Pure Agent mode)
+			logger.Infof(ctx, "No knowledge bases specified for agent, running in pure agent mode")
 		}
+	} else if len(agentConfig.KnowledgeIDs) > 0 && len(agentConfig.KnowledgeBases) == 0 {
+		// User specified individual files but no KBs - don't auto-add all KBs
+		logger.Infof(ctx, "Agent configured with %d individual knowledge ID(s), no KB auto-expansion",
+			len(agentConfig.KnowledgeIDs))
 	} else {
 		logger.Infof(ctx, "Agent configured with %d knowledge base(s): %v",
 			len(agentConfig.KnowledgeBases), agentConfig.KnowledgeBases)
 	}
 
+	// Build search targets for agent (pre-compute once to avoid repeated queries)
+	searchTargets, err := s.buildSearchTargets(ctx, tenantInfo.ID, agentConfig.KnowledgeBases, agentConfig.KnowledgeIDs)
+	if err != nil {
+		logger.Warnf(ctx, "Failed to build search targets for agent: %v", err)
+		// Continue without search targets, the tool will handle empty targets
+	}
+	agentConfig.SearchTargets = searchTargets
+	logger.Infof(ctx, "Agent search targets built: %d targets", len(searchTargets))
+
 	summaryModelID := session.SummaryModelID
 	if summaryModelID == "" && tenantInfo.ConversationConfig != nil {
 		summaryModelID = tenantInfo.ConversationConfig.SummaryModelID
diff --git a/internal/handler/initialization.go b/internal/handler/initialization.go
index 4e35e8560..73b2be758 100644
--- a/internal/handler/initialization.go
+++ b/internal/handler/initialization.go
@@ -1585,7 +1585,7 @@ func (h *InitializationHandler) checkRemoteModelConnection(ctx context.Context,
 		if strings.Contains(err.Error(), "401") || strings.Contains(err.Error(), "unauthorized") {
 			return false, "认证失败，请检查API Key"
 		} else if strings.Contains(err.Error(), "403") || strings.Contains(err.Error(), "forbidden") {
-			return false, "权限不足，请检查API Key权限"
+			return false, "权限不足，请检查API Key权限：" + err.Error()
 		} else if strings.Contains(err.Error(), "404") || strings.Contains(err.Error(), "not found") {
 			return false, "API端点不存在，请检查Base URL"
 		} else if strings.Contains(err.Error(), "timeout") {
diff --git a/internal/handler/knowledge.go b/internal/handler/knowledge.go
index 460c7f6f9..fa683b775 100644
--- a/internal/handler/knowledge.go
+++ b/internal/handler/knowledge.go
@@ -764,3 +764,37 @@ func (h *KnowledgeHandler) UpdateImageInfo(c *gin.Context) {
 		"message": "Knowledge chunk image updated successfully",
 	})
 }
+
+// SearchKnowledge godoc
+// @Summary      Search knowledge
+// @Description  Search knowledge files by keyword across all knowledge bases
+// @Tags         Knowledge
+// @Accept       json
+// @Produce      json
+// @Param        keyword   query     string  false "Keyword to search"
+// @Param        offset    query     int     false "Offset for pagination"
+// @Param        limit     query     int     false "Limit for pagination (default 20)"
+// @Success      200       {object}  map[string]interface{}     "Search results"
+// @Failure      400       {object}  errors.AppError            "Invalid request"
+// @Security     Bearer
+// @Router       /knowledge/search [get]
+func (h *KnowledgeHandler) SearchKnowledge(c *gin.Context) {
+	ctx := c.Request.Context()
+	keyword := c.Query("keyword")
+	offset, _ := strconv.Atoi(c.DefaultQuery("offset", "0"))
+	limit, _ := strconv.Atoi(c.DefaultQuery("limit", "20"))
+
+	// Retrieve knowledge entries (empty keyword returns recent files)
+	knowledges, hasMore, err := h.kgService.SearchKnowledge(ctx, keyword, offset, limit)
+	if err != nil {
+		logger.ErrorWithFields(ctx, err, nil)
+		c.Error(errors.NewInternalServerError("Failed to search knowledge").WithDetails(err.Error()))
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{
+		"success":  true,
+		"data":     knowledges,
+		"has_more": hasMore,
+	})
+}
diff --git a/internal/handler/session/agent_stream_handler.go b/internal/handler/session/agent_stream_handler.go
index bb39d6ccf..27c1eec10 100644
--- a/internal/handler/session/agent_stream_handler.go
+++ b/internal/handler/session/agent_stream_handler.go
@@ -380,8 +380,11 @@ func (h *AgentStreamHandler) handleSessionTitle(ctx context.Context, evt event.E
 		return nil
 	}
 
+	// Use background context for title event since it may arrive after stream completion
+	bgCtx := context.Background()
+
 	// Append title event to stream
-	if err := h.streamManager.AppendEvent(h.ctx, h.sessionID, h.assistantMessageID, interfaces.StreamEvent{
+	if err := h.streamManager.AppendEvent(bgCtx, h.sessionID, h.assistantMessageID, interfaces.StreamEvent{
 		ID:        evt.ID,
 		Type:      types.ResponseTypeSessionTitle,
 		Content:   data.Title,
@@ -392,7 +395,7 @@ func (h *AgentStreamHandler) handleSessionTitle(ctx context.Context, evt event.E
 			"title":      data.Title,
 		},
 	}); err != nil {
-		logger.GetLogger(h.ctx).Error("Append session title event to stream failed", "error", err)
+		logger.GetLogger(h.ctx).Warn("Append session title event to stream failed (stream may have ended)", "error", err)
 	}
 
 	return nil
diff --git a/internal/handler/session/qa.go b/internal/handler/session/qa.go
index 9b34c5e38..92dcb56fe 100644
--- a/internal/handler/session/qa.go
+++ b/internal/handler/session/qa.go
@@ -142,18 +142,19 @@ func (h *Handler) KnowledgeQA(c *gin.Context) {
 
 	// Prepare knowledge base IDs
 	knowledgeBaseIDs := request.KnowledgeBaseIDs
-	if len(knowledgeBaseIDs) == 0 && session.KnowledgeBaseID != "" {
-		knowledgeBaseIDs = []string{session.KnowledgeBaseID}
-		logger.Infof(
-			ctx,
-			"No knowledge base IDs in request, using session default: %s",
-			secutils.SanitizeForLog(session.KnowledgeBaseID),
-		)
-	}
+	// if len(knowledgeBaseIDs) == 0 && session.KnowledgeBaseID != "" {
+	// 	knowledgeBaseIDs = []string{session.KnowledgeBaseID}
+	// 	logger.Infof(
+	// 		ctx,
+	// 		"No knowledge base IDs in request, using session default: %s",
+	// 		secutils.SanitizeForLog(session.KnowledgeBaseID),
+	// 	)
+	// }
 
 	// Use shared function to handle KnowledgeQA request
 	h.handleKnowledgeQARequest(ctx, c, session, secutils.SanitizeForLog(request.Query),
 		secutils.SanitizeForLogArray(knowledgeBaseIDs),
+		secutils.SanitizeForLogArray(request.KnowledgeIds),
 		assistantMessage, true, secutils.SanitizeForLog(request.SummaryModelID), request.WebSearchEnabled)
 }
 
@@ -332,15 +333,6 @@ func (h *Handler) AgentQA(c *gin.Context) {
 			)
 		}
 
-		// Validate at least one knowledge base is available
-		if len(knowledgeBaseIDs) == 0 {
-			logger.Error(ctx, "No knowledge base available for delegation")
-			c.Error(
-				errors.NewBadRequestError("No knowledge base available. Please configure at least one knowledge base."),
-			)
-			return
-		}
-
 		logger.Infof(
 			ctx,
 			"Delegating to KnowledgeQA with knowledge bases: %s",
@@ -356,6 +348,9 @@ func (h *Handler) AgentQA(c *gin.Context) {
 			secutils.SanitizeForLogArray(
 				knowledgeBaseIDs,
 			),
+			secutils.SanitizeForLogArray(
+				request.KnowledgeIds,
+			),
 			assistantMessage,
 			false,
 			secutils.SanitizeForLog(request.SummaryModelID),
@@ -455,7 +450,8 @@ func (h *Handler) AgentQA(c *gin.Context) {
 	}()
 
 	// Handle events for SSE (blocking until connection is done)
-	h.handleAgentEventsForSSE(ctx, c, sessionID, assistantMessage.ID, requestID, eventBus)
+	// Wait for title only if session has no title (first message in session)
+	h.handleAgentEventsForSSE(ctx, c, sessionID, assistantMessage.ID, requestID, eventBus, session.Title == "")
 }
 
 // handleKnowledgeQARequest handles a KnowledgeQA request with the given parameters
@@ -466,6 +462,7 @@ func (h *Handler) handleKnowledgeQARequest(
 	session *types.Session,
 	query string,
 	knowledgeBaseIDs []string,
+	knowledgeIDs []string,
 	assistantMessage *types.Message,
 	generateTitle bool, // Whether to generate title if session has no title
 	summaryModelID string, // Optional summary model ID (overrides session default)
@@ -486,13 +483,6 @@ func (h *Handler) handleKnowledgeQARequest(
 		return
 	}
 
-	// Validate knowledge bases
-	if len(knowledgeBaseIDs) == 0 {
-		logger.Error(ctx, "No knowledge base ID available")
-		c.Error(errors.NewBadRequestError("At least one knowledge base ID is required"))
-		return
-	}
-
 	logger.Infof(ctx, "Using knowledge bases: %s", secutils.SanitizeForLog(fmt.Sprintf("%v", knowledgeBaseIDs)))
 
 	// Set headers for SSE
@@ -559,6 +549,7 @@ func (h *Handler) handleKnowledgeQARequest(
 			session,
 			query,
 			knowledgeBaseIDs,
+			knowledgeIDs,
 			assistantMessage.ID,
 			summaryModelID,
 			webSearchEnabled,
@@ -581,7 +572,8 @@ func (h *Handler) handleKnowledgeQARequest(
 	}()
 
 	// Handle events for SSE (blocking until connection is done)
-	h.handleAgentEventsForSSE(ctx, c, sessionID, assistantMessage.ID, requestID, eventBus)
+	// Wait for title only if session has no title (first message in session)
+	h.handleAgentEventsForSSE(ctx, c, sessionID, assistantMessage.ID, requestID, eventBus, session.Title == "")
 }
 
 // completeAssistantMessage marks an assistant message as complete and updates it
diff --git a/internal/handler/session/stream.go b/internal/handler/session/stream.go
index 49d8c9822..9a134cd22 100644
--- a/internal/handler/session/stream.go
+++ b/internal/handler/session/stream.go
@@ -294,11 +294,13 @@ func (h *Handler) StopSession(c *gin.Context) {
 // handleAgentEventsForSSE handles agent events for SSE streaming using an existing handler
 // The handler is already subscribed to events and AgentQA is already running
 // This function polls StreamManager and pushes events to SSE, allowing graceful handling of disconnections
+// waitForTitle: if true, wait for title event after completion (for new sessions without title)
 func (h *Handler) handleAgentEventsForSSE(
 	ctx context.Context,
 	c *gin.Context,
 	sessionID, assistantMessageID, requestID string,
 	eventBus *event.EventBus,
+	waitForTitle bool,
 ) {
 	ticker := time.NewTicker(100 * time.Millisecond)
 	defer ticker.Stop()
@@ -329,6 +331,7 @@ func (h *Handler) handleAgentEventsForSSE(
 
 			// Send any new events
 			streamCompleted := false
+			titleReceived := false
 			for _, evt := range events {
 				// Check for stop event
 				if evt.Type == types.ResponseType(event.EventStop) {
@@ -366,6 +369,11 @@ func (h *Handler) handleAgentEventsForSSE(
 					streamCompleted = true
 				}
 
+				// Check for title event
+				if evt.Type == types.ResponseTypeSessionTitle {
+					titleReceived = true
+				}
+
 				// Check if connection is still alive before writing
 				if c.Request.Context().Err() != nil {
 					log.Info("Connection closed during event sending, stopping")
@@ -379,9 +387,49 @@ func (h *Handler) handleAgentEventsForSSE(
 			// Update offset
 			lastOffset = newOffset
 
-			// Check if stream is completed
+			// Check if stream is completed - wait for title event only if needed and not already received
 			if streamCompleted {
-				log.Infof("Stream completed for session=%s, message=%s", sessionID, assistantMessageID)
+				if waitForTitle && !titleReceived {
+					log.Infof("Stream completed for session=%s, message=%s, waiting for title event", sessionID, assistantMessageID)
+					// Wait up to 3 seconds for title event after completion
+					titleTimeout := time.After(3 * time.Second)
+				titleWaitLoop:
+					for {
+						select {
+						case <-titleTimeout:
+							log.Info("Title wait timeout, closing stream")
+							break titleWaitLoop
+						case <-c.Request.Context().Done():
+							log.Info("Connection closed while waiting for title")
+							return
+						default:
+							// Check for new events (title event)
+							events, newOff, err := h.streamManager.GetEvents(c.Request.Context(), sessionID, assistantMessageID, lastOffset)
+							if err != nil {
+								log.Warnf("Error getting events while waiting for title: %v", err)
+								break titleWaitLoop
+							}
+							if len(events) > 0 {
+								for _, evt := range events {
+									response := buildStreamResponse(evt, requestID)
+									c.SSEvent("message", response)
+									c.Writer.Flush()
+									// If we got the title, we can exit
+									if evt.Type == types.ResponseTypeSessionTitle {
+										log.Infof("Title event received: %s", evt.Content)
+										break titleWaitLoop
+									}
+								}
+								lastOffset = newOff
+							} else {
+								// No events, wait a bit before checking again
+								time.Sleep(100 * time.Millisecond)
+							}
+						}
+					}
+				} else {
+					log.Infof("Stream completed for session=%s, message=%s", sessionID, assistantMessageID)
+				}
 				sendCompletionEvent(c, requestID)
 				return
 			}
diff --git a/internal/handler/session/types.go b/internal/handler/session/types.go
index b4aa6f81d..fb0ea153f 100644
--- a/internal/handler/session/types.go
+++ b/internal/handler/session/types.go
@@ -55,6 +55,7 @@ type GenerateTitleRequest struct {
 type CreateKnowledgeQARequest struct {
 	Query            string   `json:"query"              binding:"required"` // Query text for knowledge base search
 	KnowledgeBaseIDs []string `json:"knowledge_base_ids"`                    // Selected knowledge base ID for this request
+	KnowledgeIds     []string `json:"knowledge_ids"`                         // Selected knowledge ID for this request
 	AgentEnabled     bool     `json:"agent_enabled"`                         // Whether agent mode is enabled for this request
 	WebSearchEnabled bool     `json:"web_search_enabled"`                    // Whether web search is enabled for this request
 	SummaryModelID   string   `json:"summary_model_id"`                      // Optional summary model ID for this request (overrides session default)
diff --git a/internal/router/router.go b/internal/router/router.go
index 4689366a0..1b9330ce3 100644
--- a/internal/router/router.go
+++ b/internal/router/router.go
@@ -166,6 +166,8 @@ func RegisterKnowledgeRoutes(r *gin.RouterGroup, handler *handler.KnowledgeHandl
 		k.PUT("/image/:id/:chunk_id", handler.UpdateImageInfo)
 		// 批量更新知识标签
 		k.PUT("/tags", handler.UpdateKnowledgeTagBatch)
+		// 搜索知识
+		k.GET("/search", handler.SearchKnowledge)
 	}
 }
 
diff --git a/internal/types/agent.go b/internal/types/agent.go
index fb2464d66..f4529249a 100644
--- a/internal/types/agent.go
+++ b/internal/types/agent.go
@@ -15,11 +15,13 @@ type AgentConfig struct {
 	AllowedTools            []string `json:"allowed_tools"`                        // List of allowed tool names
 	Temperature             float64  `json:"temperature"`                          // LLM temperature for agent
 	KnowledgeBases          []string `json:"knowledge_bases"`                      // Accessible knowledge base IDs
+	KnowledgeIDs            []string `json:"knowledge_ids"`                        // Accessible knowledge IDs (individual documents)
 	SystemPromptWebEnabled  string   `json:"system_prompt_web_enabled,omitempty"`  // Custom prompt when web search is enabled
 	SystemPromptWebDisabled string   `json:"system_prompt_web_disabled,omitempty"` // Custom prompt when web search is disabled
 	UseCustomSystemPrompt   bool     `json:"use_custom_system_prompt"`             // Whether to use custom system prompt instead of default
 	WebSearchEnabled        bool     `json:"web_search_enabled"`                   // Whether web search tool is enabled
 	WebSearchMaxResults     int      `json:"web_search_max_results"`               // Maximum number of web search results (default: 5)
+	SearchTargets           SearchTargets `json:"-"`                               // Pre-computed unified search targets (runtime only)
 }
 
 // SessionAgentConfig represents session-level agent configuration
@@ -28,6 +30,7 @@ type SessionAgentConfig struct {
 	AgentModeEnabled bool     `json:"agent_mode_enabled"` // Whether agent mode is enabled for this session
 	WebSearchEnabled bool     `json:"web_search_enabled"` // Whether web search is enabled for this session
 	KnowledgeBases   []string `json:"knowledge_bases"`    // Accessible knowledge base IDs for this session
+	KnowledgeIDs     []string `json:"knowledge_ids"`      // Accessible knowledge IDs (individual documents) for this session
 }
 
 // Value implements driver.Valuer interface for AgentConfig
diff --git a/internal/types/chat_manage.go b/internal/types/chat_manage.go
index a41a8dcef..576507ba4 100644
--- a/internal/types/chat_manage.go
+++ b/internal/types/chat_manage.go
@@ -8,12 +8,15 @@ type ChatManage struct {
 	RewriteQuery string     `json:"rewrite_query,omitempty"` // Query after rewriting for better retrieval
 	History      []*History `json:"history,omitempty"`       // Chat history for context
 
-	KnowledgeBaseID  string   `json:"knowledge_base_id"`  // ID of the knowledge base to search against (deprecated, use KnowledgeBaseIDs)
-	KnowledgeBaseIDs []string `json:"knowledge_base_ids"` // IDs of knowledge bases to search (multi-KB support)
-	VectorThreshold  float64  `json:"vector_threshold"`   // Minimum score threshold for vector search results
-	KeywordThreshold float64  `json:"keyword_threshold"`  // Minimum score threshold for keyword search results
-	EmbeddingTopK    int      `json:"embedding_top_k"`    // Number of top results to retrieve from embedding search
-	VectorDatabase   string   `json:"vector_database"`    // Vector database type/name to use
+	KnowledgeBaseIDs []string `json:"knowledge_base_ids"`      // IDs of knowledge bases to search (multi-KB support)
+	KnowledgeIDs     []string `json:"knowledge_ids,omitempty"` // IDs of specific files to search (optional)
+	// SearchTargets is the pre-computed unified search targets
+	// Computed once at request entry point, used throughout the pipeline
+	SearchTargets    SearchTargets `json:"-"`
+	VectorThreshold  float64       `json:"vector_threshold"`  // Minimum score threshold for vector search results
+	KeywordThreshold float64       `json:"keyword_threshold"` // Minimum score threshold for keyword search results
+	EmbeddingTopK    int           `json:"embedding_top_k"`   // Number of top results to retrieve from embedding search
+	VectorDatabase   string        `json:"vector_database"`   // Vector database type/name to use
 
 	RerankModelID   string  `json:"rerank_model_id"`  // Model ID for reranking search results
 	RerankTopK      int     `json:"rerank_top_k"`     // Number of top results after reranking
@@ -33,13 +36,15 @@ type ChatManage struct {
 	RewritePromptUser    string `json:"rewrite_prompt_user"`    // Custom user prompt for rewrite stage
 
 	// Internal fields for pipeline data processing
-	SearchResult []*SearchResult `json:"-"` // Results from search phase
-	RerankResult []*SearchResult `json:"-"` // Results after reranking
-	MergeResult  []*SearchResult `json:"-"` // Final merged results after all processing
-	Entity       []string        `json:"-"` // List of identified entities
-	GraphResult  *GraphData      `json:"-"` // Graph data from search phase
-	UserContent  string          `json:"-"` // Processed user content
-	ChatResponse *ChatResponse   `json:"-"` // Final response from chat model
+	SearchResult    []*SearchResult   `json:"-"` // Results from search phase
+	RerankResult    []*SearchResult   `json:"-"` // Results after reranking
+	MergeResult     []*SearchResult   `json:"-"` // Final merged results after all processing
+	Entity          []string          `json:"-"` // List of identified entities
+	EntityKBIDs     []string          `json:"-"` // Knowledge base IDs with ExtractConfig enabled
+	EntityKnowledge map[string]string `json:"-"` // KnowledgeID -> KnowledgeBaseID mapping for graph-enabled files
+	GraphResult     *GraphData        `json:"-"` // Graph data from search phase
+	UserContent     string            `json:"-"` // Processed user content
+	ChatResponse    *ChatResponse     `json:"-"` // Final response from chat model
 
 	// Event system for streaming responses
 	EventBus  EventBusInterface `json:"-"` // EventBus for emitting streaming events
@@ -56,12 +61,16 @@ func (c *ChatManage) Clone() *ChatManage {
 	knowledgeBaseIDs := make([]string, len(c.KnowledgeBaseIDs))
 	copy(knowledgeBaseIDs, c.KnowledgeBaseIDs)
 
+	// Deep copy knowledge IDs slice
+	knowledgeIDs := make([]string, len(c.KnowledgeIDs))
+	copy(knowledgeIDs, c.KnowledgeIDs)
+
 	return &ChatManage{
 		Query:            c.Query,
 		RewriteQuery:     c.RewriteQuery,
 		SessionID:        c.SessionID,
-		KnowledgeBaseID:  c.KnowledgeBaseID,
 		KnowledgeBaseIDs: knowledgeBaseIDs,
+		KnowledgeIDs:     knowledgeIDs,
 		VectorThreshold:  c.VectorThreshold,
 		KeywordThreshold: c.KeywordThreshold,
 		EmbeddingTopK:    c.EmbeddingTopK,
diff --git a/internal/types/embedding.go b/internal/types/embedding.go
index ffc320ad6..6fd36b4a0 100644
--- a/internal/types/embedding.go
+++ b/internal/types/embedding.go
@@ -21,6 +21,7 @@ const (
 	MatchTypeRelationChunk // 关系Chunk匹配类型
 	MatchTypeGraph
 	MatchTypeWebSearch // 网络搜索匹配类型
+	MatchTypeDirectLoad // 直接加载匹配类型
 )
 
 // IndexInfo contains information about indexed content
diff --git a/internal/types/interfaces/knowledge.go b/internal/types/interfaces/knowledge.go
index 59ced1cc3..4f3edb230 100644
--- a/internal/types/interfaces/knowledge.go
+++ b/internal/types/interfaces/knowledge.go
@@ -119,6 +119,8 @@ type KnowledgeService interface {
 	SaveKBCloneProgress(ctx context.Context, progress *types.KBCloneProgress) error
 	// GetFAQImportProgress retrieves the progress of an FAQ import task
 	GetFAQImportProgress(ctx context.Context, taskID string) (*types.FAQImportProgress, error)
+	// SearchKnowledge searches knowledge items by keyword across the tenant.
+	SearchKnowledge(ctx context.Context, keyword string, offset, limit int) ([]*types.Knowledge, bool, error)
 }
 
 // KnowledgeRepository defines the interface for knowledge repositories.
@@ -156,4 +158,6 @@ type KnowledgeRepository interface {
 	CountKnowledgeByKnowledgeBaseID(ctx context.Context, tenantID uint64, kbID string) (int64, error)
 	// CountKnowledgeByStatus counts the number of knowledge items with the specified parse status.
 	CountKnowledgeByStatus(ctx context.Context, tenantID uint64, kbID string, parseStatuses []string) (int64, error)
+	// SearchKnowledge searches knowledge items by keyword across the tenant.
+	SearchKnowledge(ctx context.Context, tenantID uint64, keyword string, offset, limit int) ([]*types.Knowledge, bool, error)
 }
diff --git a/internal/types/interfaces/knowledgebase.go b/internal/types/interfaces/knowledgebase.go
index e8e91e86a..7ee009f2e 100644
--- a/internal/types/interfaces/knowledgebase.go
+++ b/internal/types/interfaces/knowledgebase.go
@@ -111,6 +111,15 @@ type KnowledgeBaseRepository interface {
 	//   - Possible errors such as record not existing, database errors, etc.
 	GetKnowledgeBaseByID(ctx context.Context, id string) (*types.KnowledgeBase, error)
 
+	// GetKnowledgeBaseByIDs queries knowledge bases by multiple IDs
+	// Parameters:
+	//   - ctx: Context information
+	//   - ids: List of knowledge base IDs
+	// Returns:
+	//   - List of knowledge base objects
+	//   - Possible errors such as database errors, etc.
+	GetKnowledgeBaseByIDs(ctx context.Context, ids []string) ([]*types.KnowledgeBase, error)
+
 	// ListKnowledgeBases lists all knowledge bases in the system
 	// Parameters:
 	//   - ctx: Context information
diff --git a/internal/types/interfaces/session.go b/internal/types/interfaces/session.go
index e344e6141..b82623ff8 100644
--- a/internal/types/interfaces/session.go
+++ b/internal/types/interfaces/session.go
@@ -28,11 +28,12 @@ type SessionService interface {
 	GenerateTitleAsync(ctx context.Context, session *types.Session, userQuery string, eventBus *event.EventBus)
 	// KnowledgeQA performs knowledge-based question answering
 	// knowledgeBaseIDs: list of knowledge base IDs to search (supports multi-KB)
+	// knowledgeIDs: list of specific knowledge (file) IDs to search
 	// summaryModelID: optional summary model ID override (if empty, uses session/KB default)
 	// webSearchEnabled: whether to enable web search to supplement knowledge base results
 	// Events are emitted through eventBus (references, answer chunks, completion)
 	KnowledgeQA(ctx context.Context,
-		session *types.Session, query string, knowledgeBaseIDs []string,
+		session *types.Session, query string, knowledgeBaseIDs []string, knowledgeIDs []string,
 		assistantMessageID string, summaryModelID string, webSearchEnabled bool, eventBus *event.EventBus,
 	) error
 	// KnowledgeQAByEvent performs knowledge-based question answering by event
diff --git a/internal/types/knowledge.go b/internal/types/knowledge.go
index 77627b2e4..ba38d0ed2 100644
--- a/internal/types/knowledge.go
+++ b/internal/types/knowledge.go
@@ -103,6 +103,8 @@ type Knowledge struct {
 	ErrorMessage string `json:"error_message"`
 	// Deletion time of the knowledge
 	DeletedAt gorm.DeletedAt `json:"deleted_at"         gorm:"index"`
+	// Knowledge base name (not stored in database, populated on query)
+	KnowledgeBaseName string `json:"knowledge_base_name" gorm:"-"`
 }
 
 // GetMetadata returns the metadata as a map[string]string.
diff --git a/internal/types/retriever.go b/internal/types/retriever.go
index c42e59406..d486cc3d3 100644
--- a/internal/types/retriever.go
+++ b/internal/types/retriever.go
@@ -30,6 +30,8 @@ type RetrieveParams struct {
 	Embedding []float32
 	// Knowledge base IDs
 	KnowledgeBaseIDs []string
+	// Knowledge IDs
+	KnowledgeIDs []string
 	// Excluded knowledge IDs
 	ExcludeKnowledgeIDs []string
 	// Excluded chunk IDs
diff --git a/internal/types/search.go b/internal/types/search.go
index f40107c35..95617b3a2 100644
--- a/internal/types/search.go
+++ b/internal/types/search.go
@@ -5,6 +5,44 @@ import (
 	"encoding/json"
 )
 
+// SearchTargetType represents the type of search target
+type SearchTargetType string
+
+const (
+	// SearchTargetTypeKnowledgeBase - search entire knowledge base
+	SearchTargetTypeKnowledgeBase SearchTargetType = "knowledge_base"
+	// SearchTargetTypeKnowledge - search specific knowledge files within a knowledge base
+	SearchTargetTypeKnowledge SearchTargetType = "knowledge"
+)
+
+// SearchTarget represents a unified search target
+// Either search an entire knowledge base, or specific knowledge files within a knowledge base
+type SearchTarget struct {
+	// Type of search target
+	Type SearchTargetType `json:"type"`
+	// KnowledgeBaseID is the ID of the knowledge base to search
+	KnowledgeBaseID string `json:"knowledge_base_id"`
+	// KnowledgeIDs is the list of specific knowledge IDs to search within the knowledge base
+	// Only used when Type is SearchTargetTypeKnowledge
+	KnowledgeIDs []string `json:"knowledge_ids,omitempty"`
+}
+
+// SearchTargets is a list of search targets, pre-computed at request entry point
+type SearchTargets []*SearchTarget
+
+// GetAllKnowledgeBaseIDs returns all unique knowledge base IDs from the search targets
+func (st SearchTargets) GetAllKnowledgeBaseIDs() []string {
+	seen := make(map[string]bool)
+	var result []string
+	for _, t := range st {
+		if !seen[t.KnowledgeBaseID] {
+			seen[t.KnowledgeBaseID] = true
+			result = append(result, t.KnowledgeBaseID)
+		}
+	}
+	return result
+}
+
 // SearchResult represents the search result
 type SearchResult struct {
 	// ID
@@ -53,12 +91,13 @@ type SearchResult struct {
 
 // SearchParams represents the search parameters
 type SearchParams struct {
-	QueryText            string  `json:"query_text"`
-	VectorThreshold      float64 `json:"vector_threshold"`
-	KeywordThreshold     float64 `json:"keyword_threshold"`
-	MatchCount           int     `json:"match_count"`
-	DisableKeywordsMatch bool    `json:"disable_keywords_match"`
-	DisableVectorMatch   bool    `json:"disable_vector_match"`
+	QueryText            string   `json:"query_text"`
+	VectorThreshold      float64  `json:"vector_threshold"`
+	KeywordThreshold     float64  `json:"keyword_threshold"`
+	MatchCount           int      `json:"match_count"`
+	DisableKeywordsMatch bool     `json:"disable_keywords_match"`
+	DisableVectorMatch   bool     `json:"disable_vector_match"`
+	KnowledgeIDs         []string `json:"knowledge_ids"`
 }
 
 // Value implements the driver.Valuer interface, used to convert SearchResult to database value