diff --git a/src/modules/knowledge-base/knowledge-base.service.ts b/src/modules/knowledge-base/knowledge-base.service.ts
index 00c7d3a..2150a71 100644
--- a/src/modules/knowledge-base/knowledge-base.service.ts
+++ b/src/modules/knowledge-base/knowledge-base.service.ts
@@ -1,4 +1,4 @@
-import { Injectable, BadRequestException, NotFoundException, ForbiddenException } from '@nestjs/common';
+import { Injectable, BadRequestException, NotFoundException, ForbiddenException, Optional } from '@nestjs/common';
 import { KnowledgeBaseRepository } from './knowledge-base.repository';
 import { PrismaService } from '../../infrastructure/database/prisma.service';
 import { ContentSafetyService } from '../content-safety/content-safety.service';
@@ -9,7 +9,7 @@ export class KnowledgeBaseService {
   constructor(
     private readonly repository: KnowledgeBaseRepository,
     private readonly prisma: PrismaService,
-    private readonly safety?: ContentSafetyService,
+    @Optional() private readonly safety?: ContentSafetyService,
   ) {}
 
   async create(userId: string, dto: any) {