diff --git a/packages/services/conversation-service/src/infrastructure/agents/coordinator/coordinator-agent.service.ts b/packages/services/conversation-service/src/infrastructure/agents/coordinator/coordinator-agent.service.ts
index 8661803..6a37a09 100644
--- a/packages/services/conversation-service/src/infrastructure/agents/coordinator/coordinator-agent.service.ts
+++ b/packages/services/conversation-service/src/infrastructure/agents/coordinator/coordinator-agent.service.ts
@@ -204,8 +204,8 @@ export class CoordinatorAgentService implements OnModuleInit {
         return;
       }
 
-      // 1. Build messages from conversation history
-      const messages = this.buildMessages(context, userContent, attachments);
+      // 1. Build messages from conversation history (async: 文本附件需下载内容)
+      const messages = await this.buildMessages(context, userContent, attachments);
 
       // 2. Build system prompt blocks (with cache control)
       const systemPrompt = this.buildSystemPromptBlocks();
@@ -328,13 +328,16 @@ export class CoordinatorAgentService implements OnModuleInit {
   // Message Building
   // ============================================================
 
+  /** 文本类文件最大嵌入大小 (超过则截断) */
+  private readonly MAX_TEXT_EMBED_SIZE = 50_000;
+
   /**
    * 将附件转换为 Claude API content blocks
    * - image → { type: 'image', source: { type: 'url', url } }
    * - PDF   → { type: 'document', source: { type: 'url', url }, title }
-   * - text/csv/json/md → 嵌入为带文件名提示的 text block
+   * - text/csv/json/md → 下载内容嵌入为 text block（Claude 无法自行访问 URL）
    */
-  private buildAttachmentBlocks(attachments: FileAttachment[]): any[] {
+  private async buildAttachmentBlocks(attachments: FileAttachment[]): Promise<any[]> {
     const blocks: any[] = [];
 
     for (const att of attachments) {
@@ -353,17 +356,39 @@ export class CoordinatorAgentService implements OnModuleInit {
           title: att.originalName,
         });
       } else if (this.isTextBasedMime(att.mimeType)) {
-        // 文本类文件：提示模型通过 URL 获取内容
-        blocks.push({
-          type: 'text',
-          text: `[附件: ${att.originalName} (${att.mimeType})] — 文件内容可通过URL获取: ${att.downloadUrl}`,
-        });
+        // 文本类文件：下载内容并直接嵌入
+        try {
+          const textContent = await this.fetchTextContent(att.downloadUrl);
+          blocks.push({
+            type: 'text',
+            text: `--- 附件: ${att.originalName} ---\n${textContent}`,
+          });
+        } catch (err) {
+          this.logger.warn(`Failed to fetch text content for ${att.originalName}: ${err}`);
+          blocks.push({
+            type: 'text',
+            text: `[附件: ${att.originalName} — 内容加载失败]`,
+          });
+        }
       }
     }
 
     return blocks;
   }
 
+  /** 通过预签名 URL 获取文本文件内容 */
+  private async fetchTextContent(url: string): Promise<string> {
+    const response = await fetch(url);
+    if (!response.ok) {
+      throw new Error(`HTTP ${response.status}`);
+    }
+    const text = await response.text();
+    if (text.length > this.MAX_TEXT_EMBED_SIZE) {
+      return text.substring(0, this.MAX_TEXT_EMBED_SIZE) + '\n...[内容过长，已截断]';
+    }
+    return text;
+  }
+
   /** 判断是否为可直接阅读的文本类 MIME */
   private isTextBasedMime(mimeType: string): boolean {
     const textMimes = [
@@ -373,18 +398,18 @@ export class CoordinatorAgentService implements OnModuleInit {
     return textMimes.includes(mimeType) || mimeType.startsWith('text/');
   }
 
-  private buildMessages(
+  private async buildMessages(
     context: LegacyConversationContext,
     userContent: string,
     attachments?: FileAttachment[],
-  ): ClaudeMessage[] {
+  ): Promise<ClaudeMessage[]> {
     const messages: ClaudeMessage[] = [];
 
     // Convert previous messages
     if (context.previousMessages) {
       for (const msg of context.previousMessages) {
         if (msg.attachments?.length) {
-          const contentBlocks = this.buildAttachmentBlocks(msg.attachments);
+          const contentBlocks = await this.buildAttachmentBlocks(msg.attachments);
           contentBlocks.push({ type: 'text', text: msg.content });
           messages.push({ role: msg.role, content: contentBlocks });
         } else {
@@ -395,7 +420,7 @@ export class CoordinatorAgentService implements OnModuleInit {
 
     // Build current user message
     if (attachments?.length) {
-      const contentBlocks = this.buildAttachmentBlocks(attachments);
+      const contentBlocks = await this.buildAttachmentBlocks(attachments);
       contentBlocks.push({ type: 'text', text: userContent });
       messages.push({ role: 'user', content: contentBlocks });
     } else {