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 428dbf4..ea0de2f 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
@@ -449,13 +449,17 @@ export class CoordinatorAgentService implements OnModuleInit {
   ): Promise<ClaudeMessage[]> {
     const messages: ClaudeMessage[] = [];
 
-    // Convert previous messages
+    // Convert previous messages (use text placeholders for historical attachments to save tokens)
     if (context.previousMessages) {
       for (const msg of context.previousMessages) {
         if (msg.attachments?.length) {
-          const contentBlocks = await this.buildAttachmentBlocks(msg.attachments);
-          contentBlocks.push({ type: 'text', text: msg.content });
-          messages.push({ role: msg.role, content: contentBlocks });
+          const placeholders = msg.attachments.map(
+            (att) => `[用户上传了${att.type === 'image' ? '图片' : '文件'}: ${att.originalName}]`,
+          );
+          messages.push({
+            role: msg.role,
+            content: placeholders.join('\n') + '\n' + msg.content,
+          });
         } else {
           messages.push({ role: msg.role, content: msg.content });
         }