From 48595175f4f1f34dee0301647ba5c928c78254a2 Mon Sep 17 00:00:00 2001
From: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Date: Mon, 27 Jul 2026 08:23:04 +0000
Subject: [PATCH] fix(cost): treat null responses output as empty in built-in
 tool cost tracking

---
 .../llm_cost_calc/tool_call_cost_tracking.py     |  2 +-
 .../test_tool_call_cost_tracking.py              | 16 ++++++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/litellm/litellm_core_utils/llm_cost_calc/tool_call_cost_tracking.py b/litellm/litellm_core_utils/llm_cost_calc/tool_call_cost_tracking.py
index 221b1ae6eab..84bb494d574 100644
--- a/litellm/litellm_core_utils/llm_cost_calc/tool_call_cost_tracking.py
+++ b/litellm/litellm_core_utils/llm_cost_calc/tool_call_cost_tracking.py
@@ -428,7 +428,7 @@ class StandardBuiltInToolCostTracking:
         Returns:
             True if the ResponsesAPIResponse includes one of the specified output types, False otherwise.
         """
-        output = response_object.output
+        output = response_object.output or []
         for output_item in output:
             _output_type: Optional[str] = getattr(output_item, "type", None)
             if _output_type == output_type:
diff --git a/tests/test_litellm/litellm_core_utils/llm_cost_calc/test_tool_call_cost_tracking.py b/tests/test_litellm/litellm_core_utils/llm_cost_calc/test_tool_call_cost_tracking.py
index 24fd3c94ee3..4e0fb2b86ea 100644
--- a/tests/test_litellm/litellm_core_utils/llm_cost_calc/test_tool_call_cost_tracking.py
+++ b/tests/test_litellm/litellm_core_utils/llm_cost_calc/test_tool_call_cost_tracking.py
@@ -142,6 +142,22 @@ def test_get_cost_for_anthropic_web_search():
     assert cost > 0.0
 
 
+def test_response_includes_output_type_with_null_output():
+    """
+    Regression test for https://github.com/BerriAI/litellm/issues/34754
+
+    Providers may send `response.output: null`, which used to make cost tracking raise
+    `TypeError: 'NoneType' object is not iterable` and drop the response cost.
+    """
+    from litellm.types.llms.openai import ResponsesAPIResponse
+
+    response = ResponsesAPIResponse.model_construct(id="resp_1", output=None)
+
+    assert not StandardBuiltInToolCostTracking.response_includes_output_type(
+        response_object=response, output_type="web_search_call"
+    )
+
+
 def test_get_cost_for_anthropic_web_search_with_server_tool_use_dict():
     """
     Anthropic-compatible passthrough responses can construct Usage from a raw