diff --git a/litellm/responses/file_search/emulated_handler.py b/litellm/responses/file_search/emulated_handler.py
index 2ac1d3dea6..85a8f78998 100644
--- a/litellm/responses/file_search/emulated_handler.py
+++ b/litellm/responses/file_search/emulated_handler.py
@@ -339,9 +339,7 @@ def _synthesize_responses_api_response(
       output[0] = file_search_call item
       output[1] = message item (with citations)
     """
-    import litellm
-
-    return ResponsesAPIResponse(
+    synthesized = ResponsesAPIResponse(
         id=getattr(original_response, "id", f"resp_{uuid.uuid4().hex}"),
         object="response",
         created_at=getattr(original_response, "created_at", int(time.time())),
@@ -351,6 +349,9 @@ def _synthesize_responses_api_response(
         usage=getattr(original_response, "usage", None),
         error=None,
     )
+    if hasattr(original_response, "_hidden_params"):
+        synthesized._hidden_params = getattr(original_response, "_hidden_params")
+    return synthesized
 
 
 # ---------------------------------------------------------------------------
@@ -513,7 +514,7 @@ async def aresponses_with_emulated_file_search(
             input=follow_up_input,
             model=model,
             tools=None,  # no tools needed for the answer step
-            **{k: v for k, v in kwargs.items() if k not in ("tools",)},
+            **kwargs,
         ),
     )
 
diff --git a/litellm/responses/main.py b/litellm/responses/main.py
index 5438676c5f..761be5a2e1 100644
--- a/litellm/responses/main.py
+++ b/litellm/responses/main.py
@@ -742,6 +742,7 @@ def responses(
                 "previous_response_id": previous_response_id,
                 "reasoning": reasoning,
                 "store": store,
+                "background": background,
                 "stream": stream,
                 "temperature": temperature,
                 "text": text,
@@ -749,6 +750,10 @@ def responses(
                 "top_p": top_p,
                 "truncation": truncation,
                 "user": user,
+                "service_tier": service_tier,
+                "safety_identifier": safety_identifier,
+                "text_format": text_format,
+                "allowed_openai_params": allowed_openai_params,
                 "extra_headers": extra_headers,
                 "extra_query": extra_query,
                 "extra_body": extra_body,