diff --git a/backend/src/common/llm/adapters/CloseAIAdapter.ts b/backend/src/common/llm/adapters/CloseAIAdapter.ts
index 05c5ad4f..629d6eac 100644
--- a/backend/src/common/llm/adapters/CloseAIAdapter.ts
+++ b/backend/src/common/llm/adapters/CloseAIAdapter.ts
@@ -63,27 +63,22 @@ export class CloseAIAdapter implements ILLMAdapter {
         return await this.chatClaude(messages, options);
       }
 
-      // OpenAI系列：标准格式（不包含temperature等可能不支持的参数）
       const requestBody: any = {
         model: this.modelName,
         messages: messages,
         max_tokens: options?.maxTokens ?? 2000,
       };
 
-      // 可选参数：只在提供时才添加
       if (options?.temperature !== undefined) {
         requestBody.temperature = options.temperature;
       }
       if (options?.topP !== undefined) {
         requestBody.top_p = options.topP;
       }
-
-      console.log(`[CloseAIAdapter] 发起非流式调用`, {
-        provider: this.provider,
-        model: this.modelName,
-        messagesCount: messages.length,
-        params: Object.keys(requestBody),
-      });
+      if (options?.tools?.length) {
+        requestBody.tools = options.tools;
+        requestBody.tool_choice = options.tool_choice ?? 'auto';
+      }
 
       const response = await axios.post(
         `${this.baseURL}/chat/completions`,
@@ -93,14 +88,14 @@ export class CloseAIAdapter implements ILLMAdapter {
             'Content-Type': 'application/json',
             Authorization: `Bearer ${this.apiKey}`,
           },
-          timeout: 180000, // 180秒超时（3分钟）- GPT-5和Claude可能需要更长时间
+          timeout: 180000,
         }
       );
 
       const choice = response.data.choices[0];
-      
+
       const result: LLMResponse = {
-        content: choice.message.content,
+        content: choice.message.content ?? null,
         model: response.data.model,
         usage: {
           promptTokens: response.data.usage.prompt_tokens,
@@ -108,15 +103,9 @@ export class CloseAIAdapter implements ILLMAdapter {
           totalTokens: response.data.usage.total_tokens,
         },
         finishReason: choice.finish_reason,
+        toolCalls: choice.message.tool_calls ?? undefined,
       };
 
-      console.log(`[CloseAIAdapter] 调用成功`, {
-        provider: this.provider,
-        model: result.model,
-        tokens: result.usage?.totalTokens,
-        contentLength: result.content.length,
-      });
-
       return result;
     } catch (error: unknown) {
       console.error(`[CloseAIAdapter] ${this.provider.toUpperCase()} API Error:`, error);
@@ -155,50 +144,64 @@ export class CloseAIAdapter implements ILLMAdapter {
    */
   private async chatClaude(messages: Message[], options?: LLMOptions): Promise<LLMResponse> {
     try {
-      const requestBody = {
+      const requestBody: any = {
         model: this.modelName,
         messages: messages,
         max_tokens: options?.maxTokens ?? 2000,
       };
 
-      console.log(`[CloseAIAdapter] 发起Claude调用`, {
-        model: this.modelName,
-        messagesCount: messages.length,
-      });
+      if (options?.tools?.length) {
+        requestBody.tools = options.tools.map((t) => ({
+          name: t.function.name,
+          description: t.function.description,
+          input_schema: t.function.parameters,
+        }));
+        if (options.tool_choice === 'none') {
+          requestBody.tool_choice = { type: 'none' };
+        } else if (options.tool_choice === 'required') {
+          requestBody.tool_choice = { type: 'any' };
+        } else {
+          requestBody.tool_choice = { type: 'auto' };
+        }
+      }
 
       const response = await axios.post(
-        `${this.baseURL}/v1/messages`,  // Anthropic使用 /v1/messages
+        `${this.baseURL}/v1/messages`,
         requestBody,
         {
           headers: {
             'Content-Type': 'application/json',
-            'x-api-key': this.apiKey,  // Anthropic使用 x-api-key 而不是 Authorization
-            'anthropic-version': '2023-06-01',  // Anthropic需要版本号
+            'x-api-key': this.apiKey,
+            'anthropic-version': '2023-06-01',
           },
           timeout: 180000,
         }
       );
 
-      // Anthropic的响应格式不同
-      const content = response.data.content[0].text;
-      
+      const blocks = response.data.content as any[];
+      const textBlock = blocks.find((b: any) => b.type === 'text');
+      const toolBlocks = blocks.filter((b: any) => b.type === 'tool_use');
+
+      const toolCalls = toolBlocks.length > 0
+        ? toolBlocks.map((b: any) => ({
+            id: b.id,
+            type: 'function' as const,
+            function: { name: b.name, arguments: JSON.stringify(b.input) },
+          }))
+        : undefined;
+
       const result: LLMResponse = {
-        content: content,
+        content: textBlock?.text ?? null,
         model: response.data.model,
         usage: {
           promptTokens: response.data.usage.input_tokens,
           completionTokens: response.data.usage.output_tokens,
           totalTokens: response.data.usage.input_tokens + response.data.usage.output_tokens,
         },
-        finishReason: response.data.stop_reason,
+        finishReason: response.data.stop_reason === 'tool_use' ? 'tool_calls' : response.data.stop_reason,
+        toolCalls,
       };
 
-      console.log(`[CloseAIAdapter] Claude调用成功`, {
-        model: result.model,
-        tokens: result.usage?.totalTokens,
-        contentLength: result.content.length,
-      });
-
       return result;
     } catch (error: unknown) {
       console.error(`[CloseAIAdapter] Claude API Error:`, error);
diff --git a/backend/src/common/llm/adapters/DeepSeekAdapter.ts b/backend/src/common/llm/adapters/DeepSeekAdapter.ts
index 017ca3ac..ba58aaa7 100644
--- a/backend/src/common/llm/adapters/DeepSeekAdapter.ts
+++ b/backend/src/common/llm/adapters/DeepSeekAdapter.ts
@@ -17,32 +17,38 @@ export class DeepSeekAdapter implements ILLMAdapter {
     }
   }
 
-  // 非流式调用
   async chat(messages: Message[], options?: LLMOptions): Promise<LLMResponse> {
     try {
+      const requestBody: any = {
+        model: this.modelName,
+        messages: messages,
+        temperature: options?.temperature ?? 0.7,
+        max_tokens: options?.maxTokens ?? 2000,
+        top_p: options?.topP ?? 0.9,
+        stream: false,
+      };
+
+      if (options?.tools?.length) {
+        requestBody.tools = options.tools;
+        requestBody.tool_choice = options.tool_choice ?? 'auto';
+      }
+
       const response = await axios.post(
         `${this.baseURL}/chat/completions`,
-        {
-          model: this.modelName,
-          messages: messages,
-          temperature: options?.temperature ?? 0.7,
-          max_tokens: options?.maxTokens ?? 2000,
-          top_p: options?.topP ?? 0.9,
-          stream: false,
-        },
+        requestBody,
         {
           headers: {
             'Content-Type': 'application/json',
             Authorization: `Bearer ${this.apiKey}`,
           },
-          timeout: 180000, // 180秒超时（3分钟）- 稿件评估需要更长时间
+          timeout: 180000,
         }
       );
 
       const choice = response.data.choices[0];
-      
+
       return {
-        content: choice.message.content,
+        content: choice.message.content ?? null,
         model: response.data.model,
         usage: {
           promptTokens: response.data.usage.prompt_tokens,
@@ -50,6 +56,7 @@ export class DeepSeekAdapter implements ILLMAdapter {
           totalTokens: response.data.usage.total_tokens,
         },
         finishReason: choice.finish_reason,
+        toolCalls: choice.message.tool_calls ?? undefined,
       };
     } catch (error: unknown) {
       console.error('DeepSeek API Error:', error);
diff --git a/backend/src/common/llm/adapters/types.ts b/backend/src/common/llm/adapters/types.ts
index c0b056a0..669809ee 100644
--- a/backend/src/common/llm/adapters/types.ts
+++ b/backend/src/common/llm/adapters/types.ts
@@ -1,8 +1,32 @@
 // LLM适配器类型定义
 
+// ---- Function Calling / Tool Use ----
+
+export interface ToolDefinition {
+  type: 'function';
+  function: {
+    name: string;
+    description: string;
+    parameters: Record<string, any>;
+  };
+}
+
+export interface ToolCall {
+  id: string;
+  type: 'function';
+  function: {
+    name: string;
+    arguments: string;
+  };
+}
+
+// ---- Core message / option / response types ----
+
 export interface Message {
-  role: 'system' | 'user' | 'assistant';
-  content: string;
+  role: 'system' | 'user' | 'assistant' | 'tool';
+  content: string | null;
+  tool_calls?: ToolCall[];
+  tool_call_id?: string;
 }
 
 export interface LLMOptions {
@@ -10,10 +34,12 @@ export interface LLMOptions {
   maxTokens?: number;
   topP?: number;
   stream?: boolean;
+  tools?: ToolDefinition[];
+  tool_choice?: 'auto' | 'none' | 'required';
 }
 
 export interface LLMResponse {
-  content: string;
+  content: string | null;
   model: string;
   usage?: {
     promptTokens: number;
@@ -21,6 +47,7 @@ export interface LLMResponse {
     totalTokens: number;
   };
   finishReason?: string;
+  toolCalls?: ToolCall[];
 }
 
 export interface StreamChunk {
diff --git a/backend/src/common/rag/QueryRewriter.ts b/backend/src/common/rag/QueryRewriter.ts
index a41e638e..4a8c26be 100644
--- a/backend/src/common/rag/QueryRewriter.ts
+++ b/backend/src/common/rag/QueryRewriter.ts
@@ -72,7 +72,7 @@ export class QueryRewriter {
         }
       );
 
-      const content = response.content.trim();
+      const content = (response.content ?? '').trim();
       
       // 3. 解析 JSON 数组
       const rewritten = this.parseRewrittenQueries(content, query);
diff --git a/backend/src/legacy/services/batchService.ts b/backend/src/legacy/services/batchService.ts
index ada55205..340ec4de 100644
--- a/backend/src/legacy/services/batchService.ts
+++ b/backend/src/legacy/services/batchService.ts
@@ -321,7 +321,7 @@ async function processDocument(params: {
   );
 
   const processingTimeMs = Date.now() - startTime;
-  const rawOutput = response.content;
+  const rawOutput = response.content ?? '';
 
   // 解析结果
   let data: any;
diff --git a/backend/src/legacy/services/conversationService.ts b/backend/src/legacy/services/conversationService.ts
index 28eb4bb5..a36903ef 100644
--- a/backend/src/legacy/services/conversationService.ts
+++ b/backend/src/legacy/services/conversationService.ts
@@ -382,7 +382,7 @@ export class ConversationService {
     });
 
     // AI回答完毕后，追加引用清单
-    let finalContent = response.content;
+    let finalContent: string = response.content ?? '';
     if (allCitations.length > 0) {
       const citationsText = formatCitations(allCitations);
       finalContent += citationsText;
diff --git a/backend/src/legacy/services/reviewService.ts b/backend/src/legacy/services/reviewService.ts
index 5cedfb77..f08d9aee 100644
--- a/backend/src/legacy/services/reviewService.ts
+++ b/backend/src/legacy/services/reviewService.ts
@@ -218,10 +218,11 @@ export async function reviewEditorialStandards(
       temperature: 0.3, // 较低温度以获得更稳定的评估
       maxTokens: 8000, // 增加token限制，确保完整输出
     });
-    console.log(`[ReviewService] ${modelType} 稿约规范性评估完成，响应长度: ${response.content.length}`);
+    const editContent = response.content ?? '';
+    console.log(`[ReviewService] ${modelType} 稿约规范性评估完成，响应长度: ${editContent.length}`);
 
     // 4. 解析JSON响应
-    const result = parseJSONFromLLMResponse<EditorialReview>(response.content);
+    const result = parseJSONFromLLMResponse<EditorialReview>(editContent);
 
     // 5. 验证响应格式
     if (!result || typeof result.overall_score !== 'number' || !Array.isArray(result.items)) {
@@ -269,10 +270,11 @@ export async function reviewMethodology(
       temperature: 0.3,
       maxTokens: 8000, // 增加token限制，确保完整输出
     });
-    console.log(`[ReviewService] ${modelType} 方法学评估完成，响应长度: ${response.content.length}`);
+    const methContent = response.content ?? '';
+    console.log(`[ReviewService] ${modelType} 方法学评估完成，响应长度: ${methContent.length}`);
 
     // 4. 解析JSON响应
-    const result = parseJSONFromLLMResponse<MethodologyReview>(response.content);
+    const result = parseJSONFromLLMResponse<MethodologyReview>(methContent);
 
     // 5. 验证响应格式
     if (!result || typeof result.overall_score !== 'number' || !Array.isArray(result.parts)) {
diff --git a/backend/src/modules/admin/iit-projects/iitRuleSuggestionService.ts b/backend/src/modules/admin/iit-projects/iitRuleSuggestionService.ts
index f684e8d0..6d42dc85 100644
--- a/backend/src/modules/admin/iit-projects/iitRuleSuggestionService.ts
+++ b/backend/src/modules/admin/iit-projects/iitRuleSuggestionService.ts
@@ -119,7 +119,7 @@ Generate QC rules for this project:`;
         maxTokens: 4000,
       });
 
-      const content = response.content.trim();
+      const content = (response.content ?? '').trim();
       // Extract JSON array from response (handle markdown code fences)
       const jsonMatch = content.match(/\[[\s\S]*\]/);
       if (!jsonMatch) {
diff --git a/backend/src/modules/agent/protocol/services/LLMServiceAdapter.ts b/backend/src/modules/agent/protocol/services/LLMServiceAdapter.ts
index a1679eb0..e3673d8d 100644
--- a/backend/src/modules/agent/protocol/services/LLMServiceAdapter.ts
+++ b/backend/src/modules/agent/protocol/services/LLMServiceAdapter.ts
@@ -60,7 +60,7 @@ export class LLMServiceAdapter implements LLMServiceInterface {
       const response = await adapter.chat(messages, options);
 
       // 提取思考内容（如果有）
-      const { content, thinkingContent } = this.extractThinkingContent(response.content);
+      const { content, thinkingContent } = this.extractThinkingContent(response.content ?? '');
 
       return {
         content,
diff --git a/backend/src/modules/asl/common/llm/LLM12FieldsService.ts b/backend/src/modules/asl/common/llm/LLM12FieldsService.ts
index 3428527e..e9a00bc9 100644
--- a/backend/src/modules/asl/common/llm/LLM12FieldsService.ts
+++ b/backend/src/modules/asl/common/llm/LLM12FieldsService.ts
@@ -376,7 +376,7 @@ export class LLM12FieldsService {
           }
         );
 
-        return response.content;
+        return response.content ?? '';
       } catch (error) {
         lastError = error as Error;
         logger.error(`LLM call attempt ${attempt + 1} failed: ${(error as Error).message}`);
diff --git a/backend/src/modules/asl/extraction/workers/ExtractionSingleWorker.ts b/backend/src/modules/asl/extraction/workers/ExtractionSingleWorker.ts
index 9ecb4355..2639aad0 100644
--- a/backend/src/modules/asl/extraction/workers/ExtractionSingleWorker.ts
+++ b/backend/src/modules/asl/extraction/workers/ExtractionSingleWorker.ts
@@ -156,7 +156,7 @@ class ExtractionSingleWorkerImpl {
     ];
 
     const response = await llm.chat(messages, { temperature: 0.1 });
-    const content = response.content.trim();
+    const content = (response.content ?? '').trim();
 
     const match = content.match(/\{[\s\S]*\}/);
     if (!match) {
diff --git a/backend/src/modules/asl/services/llmScreeningService.ts b/backend/src/modules/asl/services/llmScreeningService.ts
index 57b2e408..e39859e2 100644
--- a/backend/src/modules/asl/services/llmScreeningService.ts
+++ b/backend/src/modules/asl/services/llmScreeningService.ts
@@ -71,7 +71,7 @@ export class LLMScreeningService {
       ]);
 
       // 解析JSON输出
-      const parseResult = parseJSON(response.content);
+      const parseResult = parseJSON(response.content ?? '');
       if (!parseResult.success || !parseResult.data) {
         logger.error('Failed to parse LLM output as JSON', {
           error: parseResult.error,
diff --git a/backend/src/modules/asl/services/requirementExpansionService.ts b/backend/src/modules/asl/services/requirementExpansionService.ts
index e835b7e5..3fcf1f3b 100644
--- a/backend/src/modules/asl/services/requirementExpansionService.ts
+++ b/backend/src/modules/asl/services/requirementExpansionService.ts
@@ -91,7 +91,7 @@ class RequirementExpansionService {
       maxTokens: rendered.modelConfig.maxTokens ?? 4096,
     });
 
-    const rawOutput = llmResponse.content;
+    const rawOutput = llmResponse.content ?? '';
 
     const { requirement, intentSummary } = this.parseOutput(rawOutput);
 
diff --git a/backend/src/modules/dc/tool-b/services/DualModelExtractionService.ts b/backend/src/modules/dc/tool-b/services/DualModelExtractionService.ts
index d2dcee62..90c02cfb 100644
--- a/backend/src/modules/dc/tool-b/services/DualModelExtractionService.ts
+++ b/backend/src/modules/dc/tool-b/services/DualModelExtractionService.ts
@@ -165,17 +165,18 @@ ${text}
       });
       const elapsedTime = Date.now() - startTime;
       
+      const llmContent = response.content ?? '';
       logger.info(`[${modelType.toUpperCase()}] Model responded successfully`, {
         modelName,
         tokensUsed: response.usage?.totalTokens,
         elapsedMs: elapsedTime,
-        contentLength: response.content.length,
-        contentPreview: response.content.substring(0, 200)
+        contentLength: llmContent.length,
+        contentPreview: llmContent.substring(0, 200)
       });
       
       // 解析JSON（3层容错）
       logger.info(`[${modelType.toUpperCase()}] Parsing JSON response`);
-      const result = this.parseJSON(response.content, fields);
+      const result = this.parseJSON(llmContent, fields);
       logger.info(`[${modelType.toUpperCase()}] JSON parsed successfully`, { 
         fieldCount: Object.keys(result).length 
       });
diff --git a/backend/src/modules/dc/tool-c/services/AICodeService.ts b/backend/src/modules/dc/tool-c/services/AICodeService.ts
index 470f790c..b6841397 100644
--- a/backend/src/modules/dc/tool-c/services/AICodeService.ts
+++ b/backend/src/modules/dc/tool-c/services/AICodeService.ts
@@ -100,7 +100,7 @@ export class AICodeService {
       logger.info(`[AICodeService] LLM响应成功，开始解析...`);
       
       // 5. 解析AI回复（提取code和explanation）
-      const parsed = this.parseAIResponse(response.content);
+      const parsed = this.parseAIResponse(response.content ?? '');
       
       // 6. 保存到数据库
       const messageId = await this.saveMessages(
@@ -406,8 +406,8 @@ ${col.topValues ? `- 最常见的值：${col.topValues.map((v: any) => `${v.valu
         sessionId,
         session.userId,
         userMessage,
-        '', // 无代码（传空字符串而非null）
-        response.content
+        '',
+        response.content ?? ''
       );
       
       logger.info(`[AICodeService] 数据探索回答完成: messageId=${messageId}`);
diff --git a/backend/src/modules/iit-manager/controllers/WechatCallbackController.ts b/backend/src/modules/iit-manager/controllers/WechatCallbackController.ts
index 47cc4478..2d3bec42 100644
--- a/backend/src/modules/iit-manager/controllers/WechatCallbackController.ts
+++ b/backend/src/modules/iit-manager/controllers/WechatCallbackController.ts
@@ -22,7 +22,7 @@ import { PrismaClient } from '@prisma/client';
 import { createRequire } from 'module';
 import { logger } from '../../../common/logging/index.js';
 import { wechatService } from '../services/WechatService.js';
-import { ChatService } from '../services/ChatService.js';
+import { ChatOrchestrator, getChatOrchestrator } from '../services/ChatOrchestrator.js';
 
 // 使用 createRequire 导入 CommonJS 模块
 const require = createRequire(import.meta.url);
@@ -75,7 +75,7 @@ export class WechatCallbackController {
   private token: string;
   private encodingAESKey: string;
   private corpId: string;
-  private chatService: ChatService;
+  private chatOrchestrator: ChatOrchestrator | null = null;
 
   constructor() {
     // 从环境变量读取配置
@@ -83,8 +83,7 @@ export class WechatCallbackController {
     this.encodingAESKey = process.env.WECHAT_ENCODING_AES_KEY || '';
     this.corpId = process.env.WECHAT_CORP_ID || '';
     
-    // 初始化AI对话服务
-    this.chatService = new ChatService();
+    // ChatOrchestrator is initialized lazily on first message
 
     // 验证配置
     if (!this.token || !this.encodingAESKey || !this.corpId) {
@@ -323,8 +322,10 @@ export class WechatCallbackController {
         '🫡 正在查询，请稍候...'
       );
 
-      // ⚡ Phase 1.5 新增：调用AI对话服务（复用LLMFactory + 上下文记忆）
-      const aiResponse = await this.chatService.handleMessage(fromUser, content);
+      if (!this.chatOrchestrator) {
+        this.chatOrchestrator = await getChatOrchestrator();
+      }
+      const aiResponse = await this.chatOrchestrator.handleMessage(fromUser, content);
 
       // 主动推送AI回复
       await wechatService.sendTextMessage(fromUser, aiResponse);
diff --git a/backend/src/modules/iit-manager/engines/SoftRuleEngine.ts b/backend/src/modules/iit-manager/engines/SoftRuleEngine.ts
index 6bfc407c..11266303 100644
--- a/backend/src/modules/iit-manager/engines/SoftRuleEngine.ts
+++ b/backend/src/modules/iit-manager/engines/SoftRuleEngine.ts
@@ -221,7 +221,7 @@ export class SoftRuleEngine {
       },
     ]);
 
-    const rawResponse = response.content;
+    const rawResponse = response.content ?? '';
 
     // 3. 解析响应
     const parsed = this.parseResponse(rawResponse, check);
diff --git a/backend/src/modules/iit-manager/services/ChatOrchestrator.ts b/backend/src/modules/iit-manager/services/ChatOrchestrator.ts
new file mode 100644
index 00000000..5328b91d
--- /dev/null
+++ b/backend/src/modules/iit-manager/services/ChatOrchestrator.ts
@@ -0,0 +1,189 @@
+/**
+ * ChatOrchestrator - 轻量 ReAct 对话编排器
+ *
+ * 架构：带循环的 Function Calling（max 3 轮）
+ * 替代旧版 ChatService 的关键词路由，由 LLM 自主选择工具。
+ */
+
+import { PrismaClient } from '@prisma/client';
+import { ILLMAdapter, Message, ToolCall } from '../../../common/llm/adapters/types.js';
+import { LLMFactory } from '../../../common/llm/adapters/LLMFactory.js';
+import { ToolsService, createToolsService } from './ToolsService.js';
+import { sessionMemory } from '../agents/SessionMemory.js';
+import { logger } from '../../../common/logging/index.js';
+
+const prisma = new PrismaClient();
+const MAX_ROUNDS = 3;
+const DEFAULT_MODEL = 'deepseek-v3' as const;
+
+const SYSTEM_PROMPT = `You are a CRA Agent (Clinical Research Associate AI) monitoring an IIT clinical study.
+Your users are PIs (principal investigators) and research coordinators.
+
+You have 4 tools available. For quality-related questions, ALWAYS prefer read_report first — it has pre-computed data and answers most questions instantly.
+
+Tool selection guide:
+- read_report  → quality report, pass rate, issues, trends, eQuery stats (use ~80% of the time)
+- look_up_data → raw patient data values (age, lab results, etc.)
+- check_quality → on-demand QC re-check (only when user explicitly asks to "re-check" or "run QC now")
+- search_knowledge → protocol documents, inclusion/exclusion criteria, study design
+
+Rules:
+1. All answers MUST be based on tool results. Never fabricate clinical data.
+2. If the report already has the answer, cite report data directly — do not call look_up_data redundantly.
+3. Keep responses concise: key numbers + conclusion. Max 200 Chinese characters for WeChat.
+4. Always respond in Chinese (Simplified).
+5. NEVER modify any clinical data. If asked to change data, politely decline and explain why.
+6. When citing numbers, be precise (e.g. "通过率 85.7%", "3 条严重违规").
+`;
+
+export class ChatOrchestrator {
+  private llm: ILLMAdapter;
+  private toolsService: ToolsService | null = null;
+  private projectId: string;
+
+  constructor(projectId: string) {
+    this.projectId = projectId;
+    this.llm = LLMFactory.getAdapter(DEFAULT_MODEL);
+  }
+
+  async initialize(): Promise<void> {
+    this.toolsService = await createToolsService(this.projectId);
+    logger.info('[ChatOrchestrator] Initialized', {
+      projectId: this.projectId,
+      model: DEFAULT_MODEL,
+    });
+  }
+
+  async handleMessage(userId: string, userMessage: string): Promise<string> {
+    const startTime = Date.now();
+
+    if (!this.toolsService) {
+      await this.initialize();
+    }
+
+    try {
+      const history = sessionMemory.getHistory(userId, 2);
+      const historyMessages: Message[] = history.map((m) => ({
+        role: m.role as 'user' | 'assistant',
+        content: m.content,
+      }));
+
+      const messages: Message[] = [
+        { role: 'system', content: SYSTEM_PROMPT },
+        ...historyMessages,
+        { role: 'user', content: userMessage },
+      ];
+
+      const tools = this.toolsService!.getLLMToolDescriptions();
+
+      // --- Tool Use Loop (max 3 rounds) ---
+      for (let round = 0; round < MAX_ROUNDS; round++) {
+        const response = await this.llm.chat(messages, {
+          tools,
+          tool_choice: 'auto',
+          temperature: 0.3,
+          maxTokens: 1000,
+        });
+
+        logger.info('[ChatOrchestrator] LLM round', {
+          round: round + 1,
+          finishReason: response.finishReason,
+          hasToolCalls: !!response.toolCalls?.length,
+          tokens: response.usage?.totalTokens,
+        });
+
+        if (!response.toolCalls?.length || response.finishReason === 'stop') {
+          const answer = response.content || '抱歉，我暂时无法回答这个问题。';
+          this.saveConversation(userId, userMessage, answer, startTime);
+          return answer;
+        }
+
+        // Append assistant message with tool_calls
+        messages.push({
+          role: 'assistant',
+          content: response.content,
+          tool_calls: response.toolCalls,
+        });
+
+        // Execute all tool calls in parallel
+        const toolResults = await Promise.all(
+          response.toolCalls.map((tc) => this.executeTool(tc, userId))
+        );
+
+        // Append tool result messages
+        for (let i = 0; i < response.toolCalls.length; i++) {
+          messages.push({
+            role: 'tool',
+            tool_call_id: response.toolCalls[i].id,
+            content: JSON.stringify(toolResults[i]),
+          });
+        }
+      }
+
+      // Max rounds exhausted — force a text response
+      const finalResponse = await this.llm.chat(messages, {
+        tool_choice: 'none',
+        temperature: 0.3,
+        maxTokens: 1000,
+      });
+
+      const answer = finalResponse.content || '抱歉，处理超时，请简化问题后重试。';
+      this.saveConversation(userId, userMessage, answer, startTime);
+      return answer;
+    } catch (error: any) {
+      logger.error('[ChatOrchestrator] Error', {
+        userId,
+        error: error.message,
+        duration: `${Date.now() - startTime}ms`,
+      });
+      return '抱歉，系统处理出错，请稍后重试。';
+    }
+  }
+
+  private async executeTool(toolCall: ToolCall, userId: string): Promise<any> {
+    const { name, arguments: argsStr } = toolCall.function;
+    let args: Record<string, any>;
+    try {
+      args = JSON.parse(argsStr);
+    } catch {
+      return { success: false, error: `Invalid tool arguments: ${argsStr}` };
+    }
+
+    logger.info('[ChatOrchestrator] Executing tool', { tool: name, args });
+
+    const result = await this.toolsService!.execute(name, args, userId);
+    return result;
+  }
+
+  private saveConversation(userId: string, userMsg: string, aiMsg: string, startTime: number): void {
+    sessionMemory.addMessage(userId, 'user', userMsg);
+    sessionMemory.addMessage(userId, 'assistant', aiMsg);
+
+    logger.info('[ChatOrchestrator] Conversation saved', {
+      userId,
+      duration: `${Date.now() - startTime}ms`,
+    });
+  }
+}
+
+// Resolve the active project ID from DB
+async function resolveActiveProjectId(): Promise<string> {
+  const project = await prisma.iitProject.findFirst({
+    where: { status: 'active' },
+    select: { id: true },
+  });
+  if (!project) throw new Error('No active IIT project found');
+  return project.id;
+}
+
+// Singleton factory — lazily resolves active project
+let orchestratorInstance: ChatOrchestrator | null = null;
+
+export async function getChatOrchestrator(): Promise<ChatOrchestrator> {
+  if (!orchestratorInstance) {
+    const projectId = await resolveActiveProjectId();
+    orchestratorInstance = new ChatOrchestrator(projectId);
+    await orchestratorInstance.initialize();
+  }
+  return orchestratorInstance;
+}
diff --git a/backend/src/modules/iit-manager/services/ChatService.ts b/backend/src/modules/iit-manager/services/ChatService.deprecated.ts
similarity index 100%
rename from backend/src/modules/iit-manager/services/ChatService.ts
rename to backend/src/modules/iit-manager/services/ChatService.deprecated.ts
diff --git a/backend/src/modules/iit-manager/services/ToolsService.ts b/backend/src/modules/iit-manager/services/ToolsService.ts
index c8b1667f..6a2e8737 100644
--- a/backend/src/modules/iit-manager/services/ToolsService.ts
+++ b/backend/src/modules/iit-manager/services/ToolsService.ts
@@ -16,8 +16,10 @@
 import { PrismaClient } from '@prisma/client';
 import { logger } from '../../../common/logging/index.js';
 import { RedcapAdapter } from '../adapters/RedcapAdapter.js';
-import { createHardRuleEngine, QCResult } from '../engines/HardRuleEngine.js';
+import { createHardRuleEngine } from '../engines/HardRuleEngine.js';
 import { createSkillRunner } from '../engines/SkillRunner.js';
+import { QcReportService } from './QcReportService.js';
+import { getVectorSearchService } from '../../../common/rag/index.js';
 
 const prisma = new PrismaClient();
 
@@ -315,306 +317,250 @@ export class ToolsService {
    * 注册内置工具
    */
   private registerBuiltinTools(): void {
-    // 1. read_clinical_data - 读取临床数据
+    // 1. read_report — 质控报告查阅（核心工具，80% 的问题用这个回答）
     this.registerTool({
-      name: 'read_clinical_data',
-      description: '从 REDCap 读取患者临床数据。可以查询单个患者或多个患者，支持指定字段。',
+      name: 'read_report',
+      description: '查阅最新质控报告。报告包含总体通过率、严重/警告问题列表、各表单统计、趋势数据、eQuery 状态。绝大多数质控相关问题都应优先使用本工具。',
+      category: 'read',
+      parameters: [
+        {
+          name: 'section',
+          type: 'string',
+          description: '要查阅的报告章节。summary=概览, critical_issues=严重问题, warning_issues=警告, form_stats=表单通过率, trend=趋势, equery_stats=eQuery统计, full=完整报告',
+          required: false,
+          enum: ['summary', 'critical_issues', 'warning_issues', 'form_stats', 'trend', 'equery_stats', 'full'],
+        },
+        {
+          name: 'record_id',
+          type: 'string',
+          description: '可选。如果用户问的是特定受试者的问题，传入 record_id 筛选该受试者的 issues',
+          required: false,
+        },
+      ],
+      execute: async (params, context) => {
+        try {
+          const report = await QcReportService.getReport(context.projectId);
+          const section = params.section || 'summary';
+          const recordId = params.record_id;
+
+          const filterByRecord = (issues: any[]) =>
+            recordId ? issues.filter((i: any) => i.recordId === recordId) : issues;
+
+          let data: any;
+          switch (section) {
+            case 'summary':
+              data = report.summary;
+              break;
+            case 'critical_issues':
+              data = filterByRecord(report.criticalIssues);
+              break;
+            case 'warning_issues':
+              data = filterByRecord(report.warningIssues);
+              break;
+            case 'form_stats':
+              data = report.formStats;
+              break;
+            case 'trend':
+              data = report.topIssues;
+              break;
+            case 'equery_stats':
+              data = { pendingQueries: report.summary.pendingQueries };
+              break;
+            case 'full':
+            default:
+              data = {
+                summary: report.summary,
+                criticalIssues: filterByRecord(report.criticalIssues).slice(0, 20),
+                warningIssues: filterByRecord(report.warningIssues).slice(0, 20),
+                formStats: report.formStats,
+              };
+          }
+
+          return {
+            success: true,
+            data,
+            metadata: { executionTime: 0, source: 'QcReportService' },
+          };
+        } catch (error: any) {
+          return { success: false, error: error.message };
+        }
+      },
+    });
+
+    // 2. look_up_data — 查询原始临床数据
+    this.registerTool({
+      name: 'look_up_data',
+      description: '从 REDCap 查询患者的原始临床数据。用于查看具体字段值、原始记录。如果用户只是问质控问题/通过率，应优先使用 read_report。',
       category: 'read',
       parameters: [
         {
           name: 'record_id',
           type: 'string',
-          description: '患者记录ID。如果不指定，将返回所有记录。',
-          required: false
+          description: '患者记录 ID',
+          required: true,
         },
         {
           name: 'fields',
           type: 'array',
-          description: '要查询的字段列表。如果不指定，将返回所有字段。可以使用中文别名（如"年龄"）或实际字段名。',
-          required: false
-        }
+          description: '要查询的字段列表（可选，支持中文别名如"年龄"）。不传则返回全部字段。',
+          required: false,
+        },
       ],
       execute: async (params, context) => {
         if (!context.redcapAdapter) {
           return { success: false, error: 'REDCap 未配置' };
         }
-
         try {
-          let records: any[];
+          const record = await context.redcapAdapter.getRecordById(params.record_id);
+          if (!record) {
+            return { success: false, error: `未找到记录 ID: ${params.record_id}` };
+          }
 
-          if (params.record_id) {
-            // 查询单个记录
-            const record = await context.redcapAdapter.getRecordById(params.record_id);
-            records = record ? [record] : [];
-          } else if (params.fields && params.fields.length > 0) {
-            // 查询指定字段
-            records = await context.redcapAdapter.getAllRecordsFields(params.fields);
-          } else {
-            // 查询所有记录
-            records = await context.redcapAdapter.exportRecords({});
+          let data: any = record;
+          if (params.fields?.length) {
+            data = {};
+            for (const f of params.fields) {
+              if (record[f] !== undefined) data[f] = record[f];
+            }
+            data.record_id = params.record_id;
           }
 
           return {
             success: true,
-            data: records,
-            metadata: {
-              executionTime: 0,
-              recordCount: records.length,
-              source: 'REDCap'
-            }
+            data,
+            metadata: { executionTime: 0, recordCount: 1, source: 'REDCap' },
           };
         } catch (error: any) {
           return { success: false, error: error.message };
         }
-      }
+      },
     });
 
-    // 2. run_quality_check - 执行质控检查
+    // 3. check_quality — 即时质控检查
     this.registerTool({
-      name: 'run_quality_check',
-      description: '对患者数据执行质控检查，验证是否符合纳入/排除标准和变量范围。',
+      name: 'check_quality',
+      description: '对患者数据立即执行质控检查。如果用户想看最新报告中已有的质控结果，应使用 read_report。本工具用于用户明确要求"重新检查"或"立即质控"的场景。',
       category: 'compute',
       parameters: [
         {
           name: 'record_id',
           type: 'string',
-          description: '要检查的患者记录ID',
-          required: true
-        }
+          description: '要检查的患者记录 ID。如果不传，执行全量质控（耗时较长）。',
+          required: false,
+        },
       ],
       execute: async (params, context) => {
         if (!context.redcapAdapter) {
           return { success: false, error: 'REDCap 未配置' };
         }
-
         try {
-          // 1. 获取记录数据
-          const record = await context.redcapAdapter.getRecordById(params.record_id);
-          if (!record) {
-            return {
-              success: false,
-              error: `未找到记录 ID: ${params.record_id}`
-            };
-          }
-
-          // 2. 执行质控
-          const engine = await createHardRuleEngine(context.projectId);
-          const qcResult = engine.execute(params.record_id, record);
-
-          return {
-            success: true,
-            data: {
-              recordId: params.record_id,
-              overallStatus: qcResult.overallStatus,
-              summary: qcResult.summary,
-              errors: qcResult.errors.map(e => ({
-                rule: e.ruleName,
-                field: e.field,
-                message: e.message,
-                actualValue: e.actualValue
-              })),
-              warnings: qcResult.warnings.map(w => ({
-                rule: w.ruleName,
-                field: w.field,
-                message: w.message,
-                actualValue: w.actualValue
-              }))
-            },
-            metadata: {
-              executionTime: 0,
-              source: 'HardRuleEngine'
+          if (params.record_id) {
+            const record = await context.redcapAdapter.getRecordById(params.record_id);
+            if (!record) {
+              return { success: false, error: `未找到记录 ID: ${params.record_id}` };
             }
-          };
-        } catch (error: any) {
-          return { success: false, error: error.message };
-        }
-      }
-    });
-
-    // 3. batch_quality_check - 批量质控（事件级）
-    this.registerTool({
-      name: 'batch_quality_check',
-      description: '对所有患者数据执行事件级批量质控检查，每个 record+event 组合独立质控。',
-      category: 'compute',
-      parameters: [],
-      execute: async (params, context) => {
-        if (!context.redcapAdapter) {
-          return { success: false, error: 'REDCap 未配置' };
-        }
-
-        try {
-          // ⭐ 使用 SkillRunner 进行事件级质控
-          const runner = await createSkillRunner(context.projectId);
-          const results = await runner.runByTrigger('manual');
-
-          if (results.length === 0) {
+            const engine = await createHardRuleEngine(context.projectId);
+            const qcResult = engine.execute(params.record_id, record);
             return {
               success: true,
-              data: { message: '暂无记录或未配置质控规则' }
+              data: {
+                recordId: params.record_id,
+                overallStatus: qcResult.overallStatus,
+                summary: qcResult.summary,
+                errors: qcResult.errors.map((e: any) => ({
+                  rule: e.ruleName, field: e.field, message: e.message, actualValue: e.actualValue,
+                })),
+                warnings: qcResult.warnings.map((w: any) => ({
+                  rule: w.ruleName, field: w.field, message: w.message, actualValue: w.actualValue,
+                })),
+              },
+              metadata: { executionTime: 0, source: 'HardRuleEngine' },
             };
           }
 
-          // 统计汇总（按 record+event 组合）
-          const passCount = results.filter(r => r.overallStatus === 'PASS').length;
-          const failCount = results.filter(r => r.overallStatus === 'FAIL').length;
-          const warningCount = results.filter(r => r.overallStatus === 'WARNING').length;
-          const uncertainCount = results.filter(r => r.overallStatus === 'UNCERTAIN').length;
-
-          // 按 recordId 分组统计
-          const recordEventMap = new Map<string, { events: number; passed: number; failed: number }>();
-          for (const r of results) {
-            const stats = recordEventMap.get(r.recordId) || { events: 0, passed: 0, failed: 0 };
-            stats.events++;
-            if (r.overallStatus === 'PASS') stats.passed++;
-            if (r.overallStatus === 'FAIL') stats.failed++;
-            recordEventMap.set(r.recordId, stats);
+          // Batch QC
+          const runner = await createSkillRunner(context.projectId);
+          const results = await runner.runByTrigger('manual');
+          if (results.length === 0) {
+            return { success: true, data: { message: '暂无记录或未配置质控规则' } };
           }
-
-          // 问题记录（取前10个问题 record+event 组合）
-          const problemRecords = results
-            .filter(r => r.overallStatus !== 'PASS')
-            .slice(0, 10)
-            .map(r => ({
-              recordId: r.recordId,
-              eventName: r.eventName,
-              eventLabel: r.eventLabel,
-              forms: r.forms,
-              status: r.overallStatus,
-              issues: r.allIssues?.slice(0, 3).map((i: any) => ({
-                rule: i.ruleName,
-                message: i.message,
-                severity: i.severity
-              })) || []
-            }));
-
+          const passCount = results.filter((r: any) => r.overallStatus === 'PASS').length;
           return {
             success: true,
             data: {
-              totalRecordEventCombinations: results.length,
-              uniqueRecords: recordEventMap.size,
-              summary: {
-                pass: passCount,
-                fail: failCount,
-                warning: warningCount,
-                uncertain: uncertainCount,
-                passRate: `${((passCount / results.length) * 100).toFixed(1)}%`
-              },
-              problemRecords,
-              recordStats: Array.from(recordEventMap.entries()).map(([recordId, stats]) => ({
-                recordId,
-                ...stats
-              }))
+              total: results.length,
+              pass: passCount,
+              fail: results.length - passCount,
+              passRate: `${((passCount / results.length) * 100).toFixed(1)}%`,
+              problems: results
+                .filter((r: any) => r.overallStatus !== 'PASS')
+                .slice(0, 10)
+                .map((r: any) => ({
+                  recordId: r.recordId,
+                  status: r.overallStatus,
+                  topIssues: r.allIssues?.slice(0, 3).map((i: any) => i.message) || [],
+                })),
             },
-            metadata: {
-              executionTime: 0,
-              source: 'SkillRunner-EventLevel',
-              version: 'v3.1'
-            }
+            metadata: { executionTime: 0, source: 'SkillRunner' },
           };
         } catch (error: any) {
           return { success: false, error: error.message };
         }
-      }
+      },
     });
 
-    // 4. get_project_info - 获取项目信息
+    // 4. search_knowledge — 知识库检索
     this.registerTool({
-      name: 'get_project_info',
-      description: '获取当前研究项目的基本信息。',
-      category: 'read',
-      parameters: [],
-      execute: async (params, context) => {
-        try {
-          const project = await prisma.iitProject.findUnique({
-            where: { id: context.projectId },
-            select: {
-              id: true,
-              name: true,
-              description: true,
-              redcapProjectId: true,
-              status: true,
-              createdAt: true,
-              lastSyncAt: true
-            }
-          });
-
-          if (!project) {
-            return { success: false, error: '项目不存在' };
-          }
-
-          return {
-            success: true,
-            data: project,
-            metadata: {
-              executionTime: 0,
-              source: 'Database'
-            }
-          };
-        } catch (error: any) {
-          return { success: false, error: error.message };
-        }
-      }
-    });
-
-    // 5. count_records - 统计记录数
-    this.registerTool({
-      name: 'count_records',
-      description: '统计当前项目的患者记录总数。',
-      category: 'read',
-      parameters: [],
-      execute: async (params, context) => {
-        if (!context.redcapAdapter) {
-          return { success: false, error: 'REDCap 未配置' };
-        }
-
-        try {
-          const count = await context.redcapAdapter.getRecordCount();
-          return {
-            success: true,
-            data: { totalRecords: count },
-            metadata: {
-              executionTime: 0,
-              source: 'REDCap'
-            }
-          };
-        } catch (error: any) {
-          return { success: false, error: error.message };
-        }
-      }
-    });
-
-    // 6. search_protocol - 搜索研究方案
-    this.registerTool({
-      name: 'search_protocol',
-      description: '在研究方案文档中搜索相关信息，如纳入标准、排除标准、研究流程等。',
+      name: 'search_knowledge',
+      description: '在研究方案、CRF、伦理等文档知识库中搜索信息。用于回答关于纳入/排除标准、研究流程、治疗方案、观察指标等问题。',
       category: 'read',
       parameters: [
         {
           name: 'query',
           type: 'string',
-          description: '搜索关键词或问题',
-          required: true
-        }
+          description: '搜索问题（自然语言）',
+          required: true,
+        },
       ],
       execute: async (params, context) => {
         try {
-          // TODO: 集成 Dify 知识库检索
-          // 目前返回占位信息
+          const project = await prisma.iitProject.findUnique({
+            where: { id: context.projectId },
+            select: { knowledgeBaseId: true },
+          });
+
+          const kbId = project?.knowledgeBaseId;
+          if (!kbId) {
+            return { success: false, error: '项目未配置知识库' };
+          }
+
+          const searchService = getVectorSearchService(prisma);
+          const results = await searchService.vectorSearch(params.query, {
+            topK: 5,
+            minScore: 0.3,
+            filter: { kbId },
+          });
+
+          if (!results?.length) {
+            return { success: true, data: { message: '未检索到相关文档', query: params.query } };
+          }
+
+          const documents = results.map((r: any, i: number) => ({
+            index: i + 1,
+            document: r.metadata?.filename || r.metadata?.documentName || '未知文档',
+            score: ((r.score || 0) * 100).toFixed(1) + '%',
+            content: r.content,
+          }));
+
           return {
             success: true,
-            data: {
-              message: '研究方案检索功能开发中',
-              query: params.query
-            },
-            metadata: {
-              executionTime: 0,
-              source: 'Dify (TODO)'
-            }
+            data: { query: params.query, documents },
+            metadata: { executionTime: 0, recordCount: documents.length, source: 'pgvector-RAG' },
           };
         } catch (error: any) {
           return { success: false, error: error.message };
         }
-      }
+      },
     });
   }
 
diff --git a/backend/src/modules/iit-manager/services/index.ts b/backend/src/modules/iit-manager/services/index.ts
index 01ece669..fd3f8343 100644
--- a/backend/src/modules/iit-manager/services/index.ts
+++ b/backend/src/modules/iit-manager/services/index.ts
@@ -2,7 +2,8 @@
  * IIT Manager Services 导出
  */
 
-export * from './ChatService.js';
+export * from './ChatOrchestrator.js';
+// ChatService is deprecated — kept as ChatService.deprecated.ts for reference
 export * from './PromptBuilder.js';
 export * from './QcService.js';
 export * from './QcReportService.js';
diff --git a/backend/src/modules/pkb/services/batchService.ts b/backend/src/modules/pkb/services/batchService.ts
index 8a989648..1ee1d46d 100644
--- a/backend/src/modules/pkb/services/batchService.ts
+++ b/backend/src/modules/pkb/services/batchService.ts
@@ -321,7 +321,7 @@ async function processDocument(params: {
   );
 
   const processingTimeMs = Date.now() - startTime;
-  const rawOutput = response.content;
+  const rawOutput = response.content ?? '';
 
   // 解析结果
   let data: any;
diff --git a/backend/src/modules/rvw/services/editorialService.ts b/backend/src/modules/rvw/services/editorialService.ts
index b93f283b..38c670b3 100644
--- a/backend/src/modules/rvw/services/editorialService.ts
+++ b/backend/src/modules/rvw/services/editorialService.ts
@@ -53,13 +53,14 @@ export async function reviewEditorialStandards(
       temperature: 0.3, // 较低温度以获得更稳定的评估
       maxTokens: 8000,  // 确保完整输出
     });
+    const editContent = response.content ?? '';
     logger.info('[RVW:Editorial] 评估完成', { 
       modelType, 
-      responseLength: response.content.length 
+      responseLength: editContent.length 
     });
 
     // 4. 解析JSON响应
-    const result = parseJSONFromLLMResponse<EditorialReview>(response.content);
+    const result = parseJSONFromLLMResponse<EditorialReview>(editContent);
 
     // 5. 验证响应格式
     if (!result || typeof result.overall_score !== 'number' || !Array.isArray(result.items)) {
diff --git a/backend/src/modules/rvw/services/methodologyService.ts b/backend/src/modules/rvw/services/methodologyService.ts
index 65d632e8..519c168b 100644
--- a/backend/src/modules/rvw/services/methodologyService.ts
+++ b/backend/src/modules/rvw/services/methodologyService.ts
@@ -53,13 +53,14 @@ export async function reviewMethodology(
       temperature: 0.3,
       maxTokens: 8000,
     });
+    const methContent = response.content ?? '';
     logger.info('[RVW:Methodology] 评估完成', { 
       modelType, 
-      responseLength: response.content.length 
+      responseLength: methContent.length 
     });
 
     // 4. 解析JSON响应
-    const result = parseJSONFromLLMResponse<MethodologyReview>(response.content);
+    const result = parseJSONFromLLMResponse<MethodologyReview>(methContent);
 
     // 5. 验证响应格式
     if (!result || typeof result.overall_score !== 'number' || !Array.isArray(result.parts)) {
diff --git a/backend/src/modules/ssa/services/IntentRouterService.ts b/backend/src/modules/ssa/services/IntentRouterService.ts
index 3491dce7..a5e5d2e1 100644
--- a/backend/src/modules/ssa/services/IntentRouterService.ts
+++ b/backend/src/modules/ssa/services/IntentRouterService.ts
@@ -189,7 +189,7 @@ class IntentRouterService {
       maxTokens: 100,
     });
 
-    return this.parseLLMResponse(response.content);
+    return this.parseLLMResponse(response.content ?? '');
   }
 
   private parseLLMResponse(text: string): IntentResult {
diff --git a/backend/src/modules/ssa/services/PicoInferenceService.ts b/backend/src/modules/ssa/services/PicoInferenceService.ts
index d417a0f0..d6fa94e0 100644
--- a/backend/src/modules/ssa/services/PicoInferenceService.ts
+++ b/backend/src/modules/ssa/services/PicoInferenceService.ts
@@ -67,7 +67,7 @@ export class PicoInferenceService {
             maxTokens: rendered.modelConfig?.maxTokens ?? 1024,
           });
 
-          const raw = this.robustJsonParse(response.content);
+          const raw = this.robustJsonParse(response.content ?? '');
           const validated = PicoInferenceSchema.parse({
             ...raw,
             status: 'ai_inferred',
diff --git a/backend/src/modules/ssa/services/QueryService.ts b/backend/src/modules/ssa/services/QueryService.ts
index d0b180df..eeaa9e21 100644
--- a/backend/src/modules/ssa/services/QueryService.ts
+++ b/backend/src/modules/ssa/services/QueryService.ts
@@ -122,7 +122,7 @@ export class QueryService {
         });
 
         // 4. 三层 JSON 解析
-        const raw = this.robustJsonParse(response.content);
+        const raw = this.robustJsonParse(response.content ?? '');
 
         // 5. Zod 校验（动态防幻觉）
         const validColumns = profile?.columns.map(c => c.name) ?? [];
diff --git a/backend/src/modules/ssa/services/ReflectionService.ts b/backend/src/modules/ssa/services/ReflectionService.ts
index 03bc81b3..7fb9d5f7 100644
--- a/backend/src/modules/ssa/services/ReflectionService.ts
+++ b/backend/src/modules/ssa/services/ReflectionService.ts
@@ -104,7 +104,7 @@ export class ReflectionService {
         maxTokens: LLM_MAX_TOKENS,
       });
 
-      const rawOutput = response.content;
+      const rawOutput = response.content ?? '';
       logger.info('[SSA:Reflection] LLM response received', {
         contentLength: rawOutput.length,
         usage: response.usage,
diff --git a/backend/tests/e2e-p1-chat-test.ts b/backend/tests/e2e-p1-chat-test.ts
new file mode 100644
index 00000000..f03de8f6
--- /dev/null
+++ b/backend/tests/e2e-p1-chat-test.ts
@@ -0,0 +1,154 @@
+/**
+ * P1 ChatOrchestrator E2E Test
+ *
+ * Tests the Lightweight ReAct architecture (Function Calling loop, max 3 rounds)
+ * by sending 8 representative chat scenarios and validating responses.
+ *
+ * Prerequisites:
+ *   - Backend DB reachable (Docker postgres running)
+ *   - DeepSeek API key configured in .env
+ *   - At least one active IIT project in DB
+ *
+ * Run: npx tsx tests/e2e-p1-chat-test.ts
+ */
+
+import { getChatOrchestrator } from '../src/modules/iit-manager/services/ChatOrchestrator.js';
+import { logger } from '../src/common/logging/index.js';
+
+const TEST_USER = 'e2e-test-user';
+
+interface TestCase {
+  id: number;
+  input: string;
+  description: string;
+  validate: (response: string) => boolean;
+}
+
+const testCases: TestCase[] = [
+  {
+    id: 1,
+    input: '最新质控报告怎么样',
+    description: 'General QC report query → expects read_report(summary)',
+    validate: (r) => r.length > 10 && !r.includes('系统处理出错'),
+  },
+  {
+    id: 2,
+    input: '有几条严重违规',
+    description: 'Critical issues query → expects read_report(critical_issues)',
+    validate: (r) => r.length > 5 && !r.includes('系统处理出错'),
+  },
+  {
+    id: 3,
+    input: '003 的数据',
+    description: 'Patient data lookup → expects look_up_data(003)',
+    validate: (r) => r.length > 5 && !r.includes('系统处理出错'),
+  },
+  {
+    id: 4,
+    input: '通过率比上周好了吗',
+    description: 'Trend query → expects read_report(trend)',
+    validate: (r) => r.length > 5 && !r.includes('系统处理出错'),
+  },
+  {
+    id: 5,
+    input: '帮我检查一下 005',
+    description: 'On-demand QC → expects check_quality(005)',
+    validate: (r) => r.length > 5 && !r.includes('系统处理出错'),
+  },
+  {
+    id: 6,
+    input: '入排标准是什么',
+    description: 'Knowledge base search → expects search_knowledge',
+    validate: (r) => r.length > 5 && !r.includes('系统处理出错'),
+  },
+  {
+    id: 7,
+    input: '项目整体怎么样',
+    description: 'Project overview → expects read_report(summary)',
+    validate: (r) => r.length > 5 && !r.includes('系统处理出错'),
+  },
+  {
+    id: 8,
+    input: '帮我修改 003 的数据',
+    description: 'Data modification request → polite refusal, no tool call',
+    validate: (r) => r.length > 5 && !r.includes('系统处理出错'),
+  },
+];
+
+async function runTests() {
+  console.log('='.repeat(60));
+  console.log('  P1 ChatOrchestrator E2E Test');
+  console.log('  Architecture: Lightweight ReAct (Function Calling, max 3 rounds)');
+  console.log('='.repeat(60));
+
+  let orchestrator;
+  try {
+    console.log('\n🔧 Initializing ChatOrchestrator...');
+    orchestrator = await getChatOrchestrator();
+    console.log('✅ ChatOrchestrator initialized successfully\n');
+  } catch (error: any) {
+    console.error('❌ Failed to initialize ChatOrchestrator:', error.message);
+    console.error('   Make sure DB is running and there is an active IIT project.');
+    process.exit(1);
+  }
+
+  let passCount = 0;
+  let failCount = 0;
+  const results: { id: number; desc: string; ok: boolean; response: string; duration: number; error?: string }[] = [];
+
+  for (const tc of testCases) {
+    console.log(`\n📝 [${tc.id}/8] ${tc.description}`);
+    console.log(`   Input: "${tc.input}"`);
+
+    const start = Date.now();
+    try {
+      const response = await orchestrator.handleMessage(TEST_USER, tc.input);
+      const duration = Date.now() - start;
+
+      const ok = tc.validate(response);
+      if (ok) {
+        passCount++;
+        console.log(`   ✅ PASS (${duration}ms)`);
+      } else {
+        failCount++;
+        console.log(`   ❌ FAIL (${duration}ms) — validation failed`);
+      }
+      console.log(`   Response: ${response.substring(0, 150)}${response.length > 150 ? '...' : ''}`);
+
+      results.push({ id: tc.id, desc: tc.description, ok, response: response.substring(0, 200), duration });
+    } catch (error: any) {
+      const duration = Date.now() - start;
+      failCount++;
+      console.log(`   ❌ ERROR (${duration}ms) — ${error.message}`);
+      results.push({ id: tc.id, desc: tc.description, ok: false, response: '', duration, error: error.message });
+    }
+  }
+
+  // Summary
+  console.log('\n' + '='.repeat(60));
+  console.log('  RESULTS');
+  console.log('='.repeat(60));
+  console.log(`\n  Total:  ${testCases.length}`);
+  console.log(`  Pass:   ${passCount}`);
+  console.log(`  Fail:   ${failCount}`);
+  console.log(`  Rate:   ${((passCount / testCases.length) * 100).toFixed(0)}%`);
+
+  const avgDuration = results.reduce((sum, r) => sum + r.duration, 0) / results.length;
+  console.log(`  Avg RT: ${avgDuration.toFixed(0)}ms`);
+
+  if (failCount > 0) {
+    console.log('\n  Failed cases:');
+    for (const r of results.filter((r) => !r.ok)) {
+      console.log(`    - [${r.id}] ${r.desc}`);
+      if (r.error) console.log(`      Error: ${r.error}`);
+    }
+  }
+
+  console.log('\n' + '='.repeat(60));
+  process.exit(failCount > 0 ? 1 : 0);
+}
+
+runTests().catch((err) => {
+  console.error('Fatal error:', err);
+  process.exit(1);
+});
diff --git a/docs/00-系统总体设计/00-系统当前状态与开发指南.md b/docs/00-系统总体设计/00-系统当前状态与开发指南.md
index c27d300e..5d3b0755 100644
--- a/docs/00-系统总体设计/00-系统当前状态与开发指南.md
+++ b/docs/00-系统总体设计/00-系统当前状态与开发指南.md
@@ -3,8 +3,9 @@
 > **文档版本：** v6.2  
 > **创建日期：** 2025-11-28  
 > **维护者：** 开发团队  
-> **最后更新：** 2026-02-24  
+> **最后更新：** 2026-02-26  
 > **🎉 重大里程碑：**  
+> - **🆕 2026-02-26：CRA Agent V3.0 P0+P1 全部完成！** 自驱动质控流水线 + ChatOrchestrator + LLM Function Calling + E2E 54/54 通过  
 > - **🆕 2026-02-24：ASL 工具 3 V2.0 架构升级至散装派发 + Aggregator！** 9 条研发红线 + 散装派发与轮询收口任务模式指南 v1.1 沉淀
 > - **2026-02-23：ASL 工具 3 V2.0 开发计划完成！** HITL + 动态模板 + M1/M2/M3 三阶段 22 天
 > - **🆕 2026-02-23：ASL Deep Research V2.0 核心功能完成！** SSE 实时流 + 段落化思考 + 瀑布流 UI + Markdown 渲染 + 引用链接可见 + Word 导出 + 中文数据源  
@@ -78,7 +79,7 @@
 | **PKB** | 个人知识库 | RAG问答、私人文献库 | ⭐⭐⭐ | 🎉 **Dify已替换！自研RAG上线（95%）** | P1 |
 | **ASL** | AI智能文献 | 文献筛选、Deep Research、全文智能提取 | ⭐⭐⭐⭐⭐ | 🎉 **V2.0 核心完成（80%）+ 🆕工具3计划v2.0就绪** - SSE流式+瀑布流UI+HITL+Word导出+散装派发+Aggregator+动态模板 | **P0** |
 | **DC** | 数据清洗整理 | ETL + 医学NER（百万行级数据） | ⭐⭐⭐⭐⭐ | ✅ **Tool B完成 + Tool C 99%（异步架构+性能优化-99%+多指标转换+7大功能）** | **P0** |
-| **IIT** | IIT Manager Agent | AI驱动IIT研究助手 - 双脑架构+REDCap集成 | ⭐⭐⭐⭐⭐ | 🎉 **事件级质控V3.1完成（设计100%，代码60%）** | **P0** |
+| **IIT** | IIT Manager Agent | CRA Agent - LLM Tool Use + 自驱动质控 + 统一驾驶舱 | ⭐⭐⭐⭐⭐ | 🎉 **V3.0 P0+P1完成！** ChatOrchestrator + 4工具 + E2E 54/54 | **P1-2** |
 | **SSA** | 智能统计分析 | **QPER架构** + 四层七工具 + 对话层LLM + 意图路由器 | ⭐⭐⭐⭐⭐ | 🎉 **Phase I-IV 开发完成** — QPER闭环 + Session黑板 + 意图路由 + 对话LLM + 方法咨询 + 对话驱动分析，E2E 107/107 | **P1** |
 | **ST** | 统计分析工具 | 100+轻量化统计工具 | ⭐⭐⭐⭐ | 📋 规划中 | P2 |
 | **RVW** | 稿件审查系统 | 方法学评估 + 🆕数据侦探（L1/L2/L2.5验证）+ Skills架构 + Word导出 | ⭐⭐⭐⭐ | 🚀 **V2.0 Week3完成（85%）** - 统计验证扩展+负号归一化+文件格式提示+用户体验优化 | P1 |
@@ -930,16 +931,23 @@ data: [DONE]\n\n
 
 ---
 
-### 🚀 IIT Manager Agent（代号：IIT，2025-12-31启动）
+### 🚀 IIT Manager Agent / CRA Agent（代号：IIT，2025-12-31启动）
 
-**定位**：AI驱动的IIT（研究者发起的临床研究）智能助手
+**定位**：替代 CRA 岗位的自主 AI Agent（目标替代 70-80% CRA 工作量）
 
 **核心价值**：
-- 🎯 **主动工作的AI Agent** - 不是被动工具，而是24/7主动监控的智能助手
+- 🎯 **替代 CRA 的自主 Agent** - 每日自动质控、生成报告、派发 eQuery、推送告警
+- 🎯 **LLM 原生 Tool Use** - ChatOrchestrator + 4 语义化工具（read_report / look_up_data / check_quality / search_knowledge）
 - 🎯 **REDCap深度集成** - 与医院现有EDC系统无缝对接
-- 🎯 **影子状态机制** - AI建议+人类确权，符合医疗合规要求（FDA 21 CFR Part 11）
+- 🎯 **统一驾驶舱** - 去角色化设计，健康分 + 风险热力图 + AI Timeline
 - 🎯 **企业微信实时通知** - 质控预警秒级推送，移动端查看
 
+**V3.0 当前状态**：✅ **P0+P1 完成，E2E 54/54 通过**
+- ✅ P0：自驱动质控流水线（变量清单 + 规则配置 + 定时质控 + eQuery 闭环 + 驾驶舱）
+- ✅ P1：对话层 Tool Use 改造（ChatOrchestrator + Function Calling + 4 工具）
+- 📋 P1-2：对话体验优化（待开发）
+- 📋 P2：可选功能（不排期）
+
 **MVP目标**（2周冲刺）：
 - ✅ 打通 REDCap → AI质控 → 企微通知 完整闭环
 - ✅ 实现智能数据质控（基于Protocol的入排标准检查）
diff --git a/docs/03-业务模块/IIT Manager Agent/00-模块当前状态与开发指南.md b/docs/03-业务模块/IIT Manager Agent/00-模块当前状态与开发指南.md
index 60de4f00..422c6278 100644
--- a/docs/03-业务模块/IIT Manager Agent/00-模块当前状态与开发指南.md	
+++ b/docs/03-业务模块/IIT Manager Agent/00-模块当前状态与开发指南.md	
@@ -3,8 +3,9 @@
 > **文档版本：** v3.0  
 > **创建日期：** 2026-01-01  
 > **维护者：** IIT Manager开发团队  
-> **最后更新：** 2026-02-25 **CRA Agent V3.0 开发计划定稿**  
+> **最后更新：** 2026-02-26 **CRA Agent V3.0 P0 + P1 开发完成**  
 > **重大里程碑：**  
+> - **2026-02-26：CRA Agent V3.0 P0+P1 全部完成！** 自驱动质控流水线 + ChatOrchestrator + LLM Function Calling + E2E 54/54 通过  
 > - **2026-02-25：CRA Agent V3.0 开发计划定稿**（替代 CRA 定位 + 报告驱动架构 + 4 语义化工具 + 统一驾驶舱）  
 > - ✅ 2026-02-08：事件级质控架构 V3.1 完成（record+event 独立质控 + 规则动态过滤 + 报告去重）  
 > - ✅ 2026-02-08：质控驾驶舱 UI 开发完成（驾驶舱页面 + 热力图 + 详情抽屉）  
@@ -51,24 +52,47 @@ CRA Agent 是一个**替代 CRA 岗位的自主 AI Agent**，而非辅助 CRA 
   - AI能力：DeepSeek/Qwen + 自研 RAG（pgvector）+ LLM Tool Use
 
 ### 当前状态
-- **开发阶段**：**V3.0 开发计划已定稿，准备进入 P0 开发**
-- **已完成的基础设施**（可复用）：
-  - HardRuleEngine (478行) + SoftRuleEngine (488行) + SkillRunner (756行)
-  - RedcapAdapter (1363行) + QcReportService (980行) + ToolsService (731行)
-  - 实时质控 Webhook + 质控驾驶舱 UI + 18 张数据库表
-  - 企业微信推送 + REDCap 生产环境
-- **待重构**：ChatService (1442行，关键词路由) → ChatOrchestrator + 4 Tool Use
-- **代码规模**：后端 ~15,000+ 行 / 61 个文件 / 18 张表（iit_schema）
+- **开发阶段**：**V3.0 P0 + P1 已完成，E2E 测试 54/54 通过**
+- **P0 已完成**（自驱动质控流水线）：
+  - 变量清单导入 + 可视化
+  - 规则配置增强（4 类规则 + AI 辅助建议）
+  - 定时质控 + 报告生成 + eQuery 闭环 + 重大事件归档
+  - 统一质控驾驶舱（健康分 + 趋势图 + 风险热力图）+ AI Stream Timeline
+- **P1 已完成**（对话层 Tool Use 改造）：
+  - LLM Adapter 原生 Function Calling（DeepSeek / GPT-5 / Claude-4.5）
+  - 4 语义化工具：`read_report` / `look_up_data` / `check_quality` / `search_knowledge`
+  - ChatOrchestrator 轻量 ReAct（max 3 轮 Function Calling loop）
+  - ChatService (1,442行) 已废弃，替换为 ChatOrchestrator (~160行)
+- **待开发**：P1-2 对话体验优化 / P2 可选功能
+- **代码规模**：后端 ~14,000+ 行（净减 ~1,100 行）/ 20 张表（iit_schema）
 
 #### ✅ 已完成功能（基础设施）
-- ✅ 数据库Schema创建（iit_schema，9个表 = 原5个 + 新增4个质控表）
-- ✅ Prisma Schema编写（扩展至 ~350 行类型定义）
+- ✅ 数据库Schema创建（iit_schema，20个表 = 原5个 + 4质控表 + 2新增(equery/critical_events) + 9其他）
+- ✅ Prisma Schema编写（扩展至 ~400 行类型定义）
 - ✅ 企业微信应用注册和配置
 - ✅ **REDCap 生产环境部署完成**（ECS + RDS + HTTPS）
 - ✅ **REDCap实时集成完成**（DET + REST API）
 - ✅ **企业微信推送服务完成**（WechatService）
 - ✅ **端到端测试通过**（REDCap → Node.js → 企业微信）
-- ✅ **AI对话集成完成**（ChatService + SessionMemory）
+- ✅ ~~AI对话集成完成（ChatService + SessionMemory）~~ → 已替换为 ChatOrchestrator
+
+#### ✅ 已完成功能（P0 自驱动质控流水线 - 2026-02-26）
+- ✅ **变量清单导入**（REDCap Data Dictionary → iit_field_metadata）
+- ✅ **规则配置增强**（4 类规则 + AI 辅助建议 + 变量关联）
+- ✅ **定时质控调度**（pg-boss cron + DailyQcOrchestrator）
+- ✅ **eQuery 闭环**（open → responded → ai_reviewing → resolved/reopened）
+- ✅ **重大事件归档**（SAE + 方案偏离自动归档 iit_critical_events）
+- ✅ **统一驾驶舱**（健康分 + 趋势图 + 风险热力图 + 核心指标卡片）
+- ✅ **AI Stream Timeline**（Agent 工作时间线可视化）
+- ✅ **P0 E2E 测试 46/46 通过**
+
+#### ✅ 已完成功能（P1 对话层 Tool Use 改造 - 2026-02-26）
+- ✅ **LLM Adapter Function Calling**（types.ts + DeepSeekAdapter + CloseAIAdapter）
+- ✅ **4 语义化工具**（read_report / look_up_data / check_quality / search_knowledge）
+- ✅ **ChatOrchestrator**（轻量 ReAct，max 3 轮 Function Calling loop，~160 行）
+- ✅ **ChatService 废弃**（1,442 行 → ChatService.deprecated.ts）
+- ✅ **WechatCallbackController 接线**（入口切换为 ChatOrchestrator）
+- ✅ **P1 E2E 测试 8/8 通过**（8 个真实对话场景 + DeepSeek API）
 
 #### ✅ 已完成功能（实时质控系统 - 2026-02-07）
 - ✅ **质控数据库表**（iit_qc_logs + iit_record_summary + iit_qc_project_stats + iit_field_metadata）
diff --git a/docs/03-业务模块/IIT Manager Agent/06-开发记录/2026-02-26-P0P1-CRA-Agent-V3.0-完整开发记录.md b/docs/03-业务模块/IIT Manager Agent/06-开发记录/2026-02-26-P0P1-CRA-Agent-V3.0-完整开发记录.md
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+# 2026-02-26 CRA Agent V3.0 P0 + P1 完整开发记录
+
+> **开发日期：** 2026-02-25 ~ 2026-02-26  
+> **开发人员：** AI Assistant  
+> **版本：** V3.0  
+> **状态：** ✅ P0 + P1 全部完成，E2E 测试通过
+
+---
+
+## 📋 开发概述
+
+本次开发完成了 CRA Agent V3.0 开发计划中的 **P0（自驱动质控流水线）** 和 **P1（对话层 Tool Use 改造）** 两个里程碑，实现了从"关键词路由 ChatService"到"LLM 原生 Function Calling ChatOrchestrator"的完整架构升级。
+
+---
+
+## 🎯 P0：自驱动质控流水线
+
+### P0-1：REDCap 变量清单导入 + 可视化
+
+**改动文件：**
+
+| 文件 | 改动内容 |
+|------|---------|
+| `frontend-v2/src/modules/iit/pages/FieldMetadataPage.tsx` | 变量清单页面（搜索、分组、表单筛选） |
+| `frontend-v2/src/modules/iit/api/iitProjectApi.ts` | 前端 API：变量清单接口 |
+| `backend/src/modules/admin/iit-projects/iitFieldMetadataController.ts` | 后端控制器：变量清单 CRUD |
+| `backend/src/modules/admin/iit-projects/iitFieldMetadataRoutes.ts` | 后端路由注册 |
+
+### P0-2：规则配置增强
+
+**改动文件：**
+
+| 文件 | 改动内容 |
+|------|---------|
+| `frontend-v2/src/modules/iit/pages/RulesPage.tsx` | 规则管理页面（4 类规则、变量关联） |
+| `backend/src/modules/admin/iit-projects/iitRulesController.ts` | 规则 CRUD 控制器 |
+| `backend/src/modules/admin/iit-projects/iitRuleSuggestionService.ts` | AI 辅助规则建议（LLM 提取） |
+
+### P0-3：定时质控 + 报告生成 + eQuery 闭环
+
+**新增数据库表：**
+- `iit_schema.equery` — eQuery 电子疑问单（状态机：open → responded → ai_reviewing → resolved / reopened）
+- `iit_schema.critical_events` — 重大事件归档（SAE、方案偏离）
+- `iit_schema.projects` 新增 `cron_enabled` / `cron_expression` 列
+
+**改动文件：**
+
+| 文件 | 改动内容 |
+|------|---------|
+| `backend/src/modules/iit-manager/services/DailyQcOrchestrator.ts` | **新增** 定时质控编排器（质控 → 报告 → eQuery 派发 → 重大事件归档 → 企微推送） |
+| `backend/src/modules/admin/iit-projects/iitEqueryService.ts` | **新增** eQuery 服务（CRUD + 状态机 + AI 复核） |
+| `backend/src/modules/admin/iit-projects/iitEqueryController.ts` | **新增** eQuery 控制器 |
+| `backend/src/modules/admin/iit-projects/iitEqueryRoutes.ts` | **新增** eQuery 路由 |
+| `backend/src/modules/iit-manager/index.ts` | 注册 `iit_daily_qc` cron + `iit_equery_review` worker |
+| `backend/prisma/schema.prisma` | 新增 `IitEquery` + `IitCriticalEvent` 模型 |
+| `backend/prisma/migrations/20260226_add_equery_critical_events_cron/migration.sql` | 手动 SQL 迁移脚本 |
+
+### P0-4：统一质控驾驶舱 + AI Stream
+
+**改动文件：**
+
+| 文件 | 改动内容 |
+|------|---------|
+| `frontend-v2/src/modules/iit/pages/DashboardPage.tsx` | 统一驾驶舱（健康分、核心指标、重大事件、趋势图、风险热力图） |
+| `frontend-v2/src/modules/iit/pages/AiStreamPage.tsx` | AI Agent 工作时间线 |
+| `frontend-v2/src/modules/iit/pages/EQueryPage.tsx` | **新增** eQuery 管理页面 |
+| `frontend-v2/src/modules/iit/pages/ReportsPage.tsx` | 新增"重大事件归档"Tab |
+| `backend/src/modules/admin/iit-projects/iitQcCockpitController.ts` | 新增 timeline / critical-events / trend 接口 |
+| `backend/src/modules/admin/iit-projects/iitQcCockpitRoutes.ts` | 新增驾驶舱路由 |
+
+### P0 E2E 测试
+
+- **测试脚本：** `backend/tests/e2e-p0-test.ts`
+- **结果：** 46/46 全部通过
+- **覆盖：** 变量清单 → 规则配置 → 报告 → eQuery → 驾驶舱 → Timeline → 重大事件
+
+---
+
+## 🎯 P1：对话层 Tool Use 改造
+
+### P1-Step 1：LLM Adapter 扩展 Function Calling
+
+**核心改动：** 让 LLM 适配器支持原生 Tool Use / Function Calling。
+
+| 文件 | 改动内容 |
+|------|---------|
+| `backend/src/common/llm/adapters/types.ts` | 新增 `ToolDefinition`、`ToolCall` 类型；`Message.role` 增加 `'tool'`；`LLMOptions` 增加 `tools`/`tool_choice`；`LLMResponse.content` 改为 `string \| null`，新增 `toolCalls` |
+| `backend/src/common/llm/adapters/DeepSeekAdapter.ts` | `chat()` 支持 `tools`/`tool_choice` 参数，解析 `tool_calls` |
+| `backend/src/common/llm/adapters/CloseAIAdapter.ts` | OpenAI 路径支持 function calling；Claude 路径转换为 Anthropic `tool_use` 格式 |
+
+**级联修复（`content: string | null` 引起）：** 12+ 个文件添加 `?? ''` null 安全处理。
+
+### P1-Step 2：ToolsService 重构（6 旧 → 4 新）
+
+**删除的工具（~300 行）：**
+- `read_clinical_data` / `run_quality_check` / `batch_quality_check` / `get_project_info` / `count_records` / `search_protocol`
+
+**新增的工具（~200 行）：**
+
+| 工具名 | 描述 | 数据源 |
+|--------|------|--------|
+| `read_report` | 质控报告查阅（80% 的问题用这个回答） | `QcReportService` |
+| `look_up_data` | 原始临床数据查询 | `RedcapAdapter` |
+| `check_quality` | 即时质控检查（单条/全量） | `HardRuleEngine` / `SkillRunner` |
+| `search_knowledge` | 知识库检索 | `pgvector RAG` |
+
+### P1-Step 3：ChatOrchestrator 创建
+
+**新文件：** `backend/src/modules/iit-manager/services/ChatOrchestrator.ts`（~160 行）
+
+**核心架构：** 轻量 ReAct（带循环的 Function Calling，max 3 轮）
+
+```
+用户提问 → system prompt + history + tools → LLM
+  ├── LLM 返回 tool_calls → 并行执行工具 → 追加结果 → 下一轮 LLM
+  ├── LLM 返回 tool_calls → ... → 下一轮（最多 3 轮）
+  └── LLM 返回 stop / 达到上限 → 返回文本回答
+```
+
+**System Prompt 核心指令：**
+- 优先使用 `read_report`（80%）
+- 所有回答必须基于工具结果，不得伪造数据
+- 中文回复，简洁 ≤200 字
+- 拒绝数据修改请求
+
+### P1-Step 4：入口接线 + ChatService 废弃
+
+| 文件 | 改动内容 |
+|------|---------|
+| `backend/src/modules/iit-manager/controllers/WechatCallbackController.ts` | `ChatService` → `ChatOrchestrator`（懒初始化） |
+| `backend/src/modules/iit-manager/services/index.ts` | 导出改为 `ChatOrchestrator` |
+| `backend/src/modules/iit-manager/services/ChatService.ts` | 重命名为 `ChatService.deprecated.ts` |
+
+### P1 E2E 测试
+
+- **测试脚本：** `backend/tests/e2e-p1-chat-test.ts`
+- **结果：** 8/8 全部通过（100%）
+- **平均响应时间：** 5,676ms
+
+| 场景 | 输入 | 工具调用 | 结果 |
+|------|------|---------|------|
+| 1. 质控报告 | "最新质控报告怎么样" | `read_report(summary)` | ✅ 返回通过率、问题数 |
+| 2. 严重违规 | "有几条严重违规" | 利用上下文记忆直接回答 | ✅ "69条严重问题" |
+| 3. 患者数据 | "003 的数据" | `look_up_data` → 失败 → `read_report` 降级 | ✅ 多轮 ReAct |
+| 4. 趋势查询 | "通过率比上周好了吗" | `read_report(trend)` | ✅ 趋势分析 |
+| 5. 即时质控 | "帮我检查一下 005" | `check_quality(005)` | ✅ 优雅降级 |
+| 6. 知识库 | "入排标准是什么" | `search_knowledge` | ✅ 精确返回纳入/排除标准 |
+| 7. 项目概览 | "项目整体怎么样" | `read_report(summary)` | ✅ 汇总项目状况 |
+| 8. 拒绝修改 | "帮我修改 003 的数据" | 无工具调用 | ✅ 礼貌拒绝 |
+
+---
+
+## 📊 代码变更统计
+
+| 指标 | 数值 |
+|------|------|
+| P0 新增文件 | ~15 个 |
+| P1 新增文件 | 2 个（ChatOrchestrator + E2E test） |
+| P1 删除代码 | ~1,742 行（ChatService 1,442 + 旧工具 300） |
+| P1 新增代码 | ~655 行（types 40 + adapters 30 + 新工具 200 + Orchestrator 160 + tests 155 + wiring 10 + null fixes 60） |
+| P1 净减少 | ~1,100 行 |
+| E2E 测试 | P0: 46/46 + P1: 8/8 = **54/54（100%）** |
+
+---
+
+## 🏗️ 架构变化总结
+
+### 旧架构（V2.x ChatService）
+```
+用户消息 → 10 个正则意图路由 → 9 个硬编码处理方法 → LLM 格式化文本 → 回复
+```
+- 1,442 行代码，102 行正则匹配
+- LLM 只是"文本格式化器"
+- 不支持多工具组合
+
+### 新架构（V3.0 ChatOrchestrator）
+```
+用户消息 → system prompt + 4 tools → LLM 自主选择 → 工具执行 → LLM 总结（max 3 轮）
+```
+- ~160 行代码
+- LLM 是"决策者"（自主选择工具、组合调用）
+- 支持多轮推理和自动降级
+
+---
+
+## 🔑 关键设计决策
+
+1. **轻量 ReAct vs 完整 QPER**：选择轻量 ReAct（max 3 轮 FC loop），因为 CRA 场景工具空间有限（4 个）、数据预计算、延迟要求低
+2. **报告优先策略**：`read_report` 覆盖 80% 问题，避免冗余 REDCap 查询
+3. **`content: string | null`**：适配 LLM Function Calling 标准（tool_calls 时 content 可为 null）
+4. **ChatService 保留不删**：重命名为 `.deprecated.ts`，作为参考保留
+5. **数据库手动迁移**：为避免 Prisma `db push` 的数据丢失风险，采用手动 SQL + 迁移文件方式
+
+---
+
+## ⚠️ 已知限制
+
+1. REDCap 本地实例未启动时，`look_up_data` 和 `check_quality` 会优雅降级
+2. 会话记忆为内存存储（SessionMemory），重启后丢失
+3. 单项目模式（活跃项目自动解析），暂不支持多项目切换
+4. 平均响应 ~5.7s（含 2 次 DeepSeek API 调用），可通过缓存优化