diff --git a/app/api/missions/route.ts b/app/api/missions/route.ts
index 1be5c9b7..cfc22b55 100644
--- a/app/api/missions/route.ts
+++ b/app/api/missions/route.ts
@@ -144,15 +144,26 @@ export async function GET(request: Request) {
 // POST endpoint to create a new mission
 export async function POST(request: Request) {
   try {
-    // Parse the request body first
     const body = await request.json();
-    
-    // Pass the body to checkAuth
-    const { authorized, userId } = await checkAuth(request, body);
-    if (!authorized || !userId) {
+    const auth = await checkAuth(request, body);
+    if (!auth.authorized || !auth.userId) {
       return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
     }
 
+    // Check for existing mission with the same name
+    const existingMission = await prisma.mission.findFirst({
+      where: {
+        name: body.name
+      }
+    });
+
+    if (existingMission) {
+      return NextResponse.json({ 
+        error: 'A mission with this name already exists',
+        existingMission 
+      }, { status: 409 });
+    }
+
     // Validate required fields
     if (!body.name || !body.niveau || !body.intention || !body.missionType || !body.donneurDOrdre || !body.projection) {
       return NextResponse.json({ 
@@ -176,21 +187,19 @@ export async function POST(request: Request) {
       }, { status: 400 });
     }
 
-    // Create the mission in the database first
+    // Create mission with default values
     const mission = await prisma.mission.create({
       data: {
         name: body.name,
-        logo: body.logo,
         oddScope: body.oddScope || [],
-        niveau: body.niveau,
-        intention: body.intention,
-        missionType: body.missionType,
-        donneurDOrdre: body.donneurDOrdre,
-        projection: body.projection,
+        niveau: body.niveau || [],
+        intention: body.intention || [],
+        missionType: body.missionType || 'hybrid',
+        donneurDOrdre: body.donneurDOrdre || [],
+        projection: body.projection || [],
         services: body.services || [],
-        participation: body.participation,
         profils: body.profils || [],
-        creatorId: userId
+        creatorId: auth.userId
       }
     });
 
@@ -231,7 +240,7 @@ export async function POST(request: Request) {
       const workflowResult = await n8nService.createMission({
         ...body,
         missionId: mission.id,
-        creatorId: userId
+        creatorId: auth.userId
       });
 
       // Update mission with integration results, even if some failed