diff --git a/frontend/src/services/api-client.ts b/frontend/src/services/api-client.ts
index adf0d56..1c24f99 100644
--- a/frontend/src/services/api-client.ts
+++ b/frontend/src/services/api-client.ts
@@ -819,6 +819,7 @@ class ApiClient {
 
     const promise = new Promise<Types.ChatMessage[]>(async (resolve, reject) => {
       try {
+        const request = formatApiRequest(chatMessage);
         const response = await fetch(`${this.baseUrl}/chat/sessions/${chatMessage.sessionId}/messages/stream`, {
           method: 'POST',
           headers: {
@@ -826,7 +827,7 @@ class ApiClient {
             'Accept': 'text/event-stream',
             'Cache-Control': 'no-cache'
           },
-          body: JSON.stringify(formatApiRequest({ chatMessage })),
+          body: JSON.stringify(request),
           signal
         });
 
diff --git a/src/backend/main.py b/src/backend/main.py
index e51e3b4..5439c4a 100644
--- a/src/backend/main.py
+++ b/src/backend/main.py
@@ -1933,21 +1933,12 @@ async def create_chat_session(
 
 @api_router.post("/chat/sessions/{session_id}/messages/stream")
 async def post_chat_session_message_stream(
-    data: Dict[str, Any] = Body(...),
+    user_message: ChatMessageUser = Body(...),
     current_user = Depends(get_current_user),
-    database: RedisDatabase = Depends(get_database),
-    request: Request = Request,
+    database: RedisDatabase = Depends(get_database)
 ):
     """Post a message to a chat session and stream the response with persistence"""
     try:
-        user_message_data = data.get("chatMessage")
-        if not user_message_data:
-            return JSONResponse(
-                status_code=400,
-                content=create_error_response("INVALID_CHAT_MESSAGE", "chatMessage cannot be empty")
-            )
-        user_message = ChatMessageUser.model_validate(user_message_data)
-                
         chat_session_data = await database.get_chat_session(user_message.session_id)
         if not chat_session_data:
             return JSONResponse(