diff --git a/backend/app/api/routes/responses.py b/backend/app/api/routes/responses.py
index 94e5f19db..c221d0e85 100644
--- a/backend/app/api/routes/responses.py
+++ b/backend/app/api/routes/responses.py
@@ -18,7 +18,7 @@
     get_conversation_by_ancestor_id,
 )
 from app.models import UserProjectOrg, OpenAIConversationCreate, OpenAIConversation
-from app.utils import APIResponse, mask_string
+from app.utils import APIResponse, mask_string, get_openai_client
 from app.core.langfuse.langfuse import LangfuseTracer
 
 logger = logging.getLogger(__name__)
@@ -126,25 +126,57 @@ def get_additional_data(request: dict) -> dict:
 
 
 def process_response(
-    request: ResponsesAPIRequest,
-    client: OpenAI,
-    assistant,
-    tracer: LangfuseTracer,
+    request_data: dict,
     project_id: int,
     organization_id: int,
-    ancestor_id: str,
-    latest_conversation: OpenAIConversation | None,
 ):
     """Process a response and send callback with results, with Langfuse tracing."""
+    # Reconstruct request object from serialized data
+    request = ResponsesAPIRequest(**request_data)
+    assistant_id = request.assistant_id
+
     logger.info(
-        f"[process_response] Starting generating response for assistant_id={mask_string(request.assistant_id)}, project_id={project_id}"
+        f"[process_response] Starting generating response for assistant_id={mask_string(assistant_id)}, project_id={project_id}"
     )
 
+    with Session(engine) as session:
+        assistant = get_assistant_by_id(session, assistant_id, project_id)
+        if not assistant:
+            logger.error(
+                f"[process_response] Assistant not found: assistant_id={mask_string(assistant_id)}, project_id={project_id}"
+            )
+            return
+
+        client = get_openai_client(session, organization_id, project_id)
+
+        langfuse_credentials = get_provider_credential(
+            session=session,
+            org_id=organization_id,
+            provider="langfuse",
+            project_id=project_id,
+        )
+        tracer = LangfuseTracer(
+            credentials=langfuse_credentials,
+            response_id=request.response_id,
+        )
+
+        # Handle ancestor_id and latest conversation logic
+        ancestor_id = request.response_id
+        latest_conversation = None
+        if ancestor_id:
+            latest_conversation = get_conversation_by_ancestor_id(
+                session=session,
+                ancestor_response_id=ancestor_id,
+                project_id=project_id,
+            )
+            if latest_conversation:
+                ancestor_id = latest_conversation.response_id
+
     tracer.start_trace(
         name="generate_response_async",
-        input={"question": request.question, "assistant_id": request.assistant_id},
+        input={"question": request.question, "assistant_id": assistant_id},
         metadata={"callback_url": request.callback_url},
-        tags=[request.assistant_id],
+        tags=[assistant_id],
     )
 
     tracer.start_generation(
@@ -177,7 +209,7 @@ def process_response(
         response_chunks = get_file_search_results(response)
 
         logger.info(
-            f"[process_response] Successfully generated response: response_id={response.id}, assistant={mask_string(request.assistant_id)}, project_id={project_id}"
+            f"[process_response] Successfully generated response: response_id={response.id}, assistant={mask_string(assistant_id)}, project_id={project_id}"
         )
 
         tracer.end_generation(
@@ -223,7 +255,7 @@ def process_response(
                 user_question=request.question,
                 response=response.output_text,
                 model=response.model,
-                assistant_id=request.assistant_id,
+                assistant_id=assistant_id,
             )
 
             create_conversation(
@@ -263,7 +295,7 @@ def process_response(
 
     if request.callback_url:
         logger.info(
-            f"[process_response] Sending callback to URL: {request.callback_url}, assistant={mask_string(request.assistant_id)}, project_id={project_id}"
+            f"[process_response] Sending callback to URL: {request.callback_url}, assistant={mask_string(assistant_id)}, project_id={project_id}"
         )
 
         # Send callback with webhook-specific response format
@@ -281,7 +313,7 @@ def process_response(
             },
         )
         logger.info(
-            f"[process_response] Callback sent successfully, assistant={mask_string(request.assistant_id)}, project_id={project_id}"
+            f"[process_response] Callback sent successfully, assistant={mask_string(assistant_id)}, project_id={project_id}"
         )
 
 
@@ -325,40 +357,11 @@ async def responses(
             "metadata": None,
         }
 
-    client = OpenAI(api_key=credentials["api_key"])
-
-    langfuse_credentials = get_provider_credential(
-        session=_session,
-        org_id=organization_id,
-        provider="langfuse",
-        project_id=project_id,
-    )
-    tracer = LangfuseTracer(
-        credentials=langfuse_credentials,
-        response_id=request.response_id,
-    )
-
-    ancestor_id = request.response_id
-    latest_conversation = None
-    if ancestor_id:
-        latest_conversation = get_conversation_by_ancestor_id(
-            session=_session,
-            ancestor_response_id=ancestor_id,
-            project_id=project_id,
-        )
-        if latest_conversation:
-            ancestor_id = latest_conversation.response_id
-
     background_tasks.add_task(
         process_response,
-        request,
-        client,
-        assistant,
-        tracer,
+        request.model_dump(),
         project_id,
         organization_id,
-        ancestor_id,
-        latest_conversation,
     )
 
     logger.info(