diff --git a/apps/ai-service/src/pipeline/course-generation.pipeline.ts b/apps/ai-service/src/pipeline/course-generation.pipeline.ts
index ddb6f01..f6efa74 100644
--- a/apps/ai-service/src/pipeline/course-generation.pipeline.ts
+++ b/apps/ai-service/src/pipeline/course-generation.pipeline.ts
@@ -1,4 +1,4 @@
-import { prisma, GenerationStatus, CourseStatus } from '@coursecraft/database';
+import { prisma, Prisma, GenerationStatus, CourseStatus } from '@coursecraft/database';
 import { generateUniqueSlug } from '@coursecraft/shared';
 import { OpenRouterProvider, CourseOutline } from '../providers/openrouter.provider';
 
@@ -245,7 +245,7 @@ export class CourseGenerationPipeline {
                 title: lesson.title,
                 order: lessonIndex,
                 durationMinutes: lesson.estimatedMinutes,
-                content: null, // Will be filled later
+                content: Prisma.JsonNull, // Will be filled later
               })),
             },
           })),
@@ -277,8 +277,8 @@ export class CourseGenerationPipeline {
         status,
         progress,
         currentStep,
-        ...(additionalData?.errorMessage && { errorMessage: additionalData.errorMessage as string }),
-        ...(status === GenerationStatus.COMPLETED && { completedAt: new Date() }),
+        ...(additionalData?.errorMessage != null ? { errorMessage: additionalData.errorMessage as string } : {}),
+        ...(status === GenerationStatus.COMPLETED ? { completedAt: new Date() } : {}),
       },
     });
   }