From 25ee7b2aeb67d2ca19ed46e4112feef3078692b9 Mon Sep 17 00:00:00 2001
From: mukktinaadh <159904553+mukktinaadh@users.noreply.github.com>
Date: Mon, 24 Aug 2026 13:24:29 +0530
Subject: [PATCH] Add usage tracking to Responses API streaming completion
 events (Fixes #38065)

- Extract usage from ResponseCompletedEvent.response.usage
- Convert ResponseAPIUsage to dict using model_dump()
- Include usage in interaction.completed/interaction.complete events
- Update tests to properly mock usage attribute

Fixes #38065
---
 .../streaming_iterator.py                                | 9 +++++++--
 .../test_gemini_interactions_transformation.py           | 7 ++++++-
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/litellm/interactions/litellm_responses_transformation/streaming_iterator.py b/litellm/interactions/litellm_responses_transformation/streaming_iterator.py
index 1a9fce5a9d7..fdab4add79f 100644
--- a/litellm/interactions/litellm_responses_transformation/streaming_iterator.py
+++ b/litellm/interactions/litellm_responses_transformation/streaming_iterator.py
@@ -135,7 +135,7 @@ class LiteLLMResponsesInteractionsStreamingIterator:
             index=0,
         )
 
-    def _build_completion_event(self, response_id: str) -> InteractionsAPIStreamingResponse:
+    def _build_completion_event(self, response_id: str, usage: dict | None = None) -> InteractionsAPIStreamingResponse:
         if self._use_legacy:
             return InteractionsAPIStreamingResponse(
                 event_type="interaction.complete",
@@ -144,6 +144,7 @@ class LiteLLMResponsesInteractionsStreamingIterator:
                 status="completed",
                 model=self.model,
                 outputs=[{"type": "text", "text": self.collected_text}],
+                usage=usage,
             )
         return InteractionsAPIStreamingResponse(
             event_type="interaction.completed",
@@ -157,6 +158,7 @@ class LiteLLMResponsesInteractionsStreamingIterator:
                     "content": [{"type": "text", "text": self.collected_text}],
                 }
             ],
+            usage=usage,
         )
 
     # ------------------------------------------------------------------
@@ -218,11 +220,14 @@ class LiteLLMResponsesInteractionsStreamingIterator:
             self.finished = True
             response: Final = responses_chunk.response
             response_id = self._interaction_id or getattr(response, "id", None) or f"interaction_{id(self)}"
+            # Extract usage from the response if available and convert to dict
+            usage_obj = getattr(response, "usage", None)
+            usage = usage_obj.model_dump() if usage_obj is not None else None
 
             terminal: Final[list[InteractionsAPIStreamingResponse]] = []
             if self.sent_content_start:
                 terminal.append(self._build_content_stop_event(response_id))
-            terminal.append(self._build_completion_event(response_id))
+            terminal.append(self._build_completion_event(response_id, usage))
             self._sent_completion_event = True
             return terminal
 
diff --git a/tests/test_litellm/interactions/test_gemini_interactions_transformation.py b/tests/test_litellm/interactions/test_gemini_interactions_transformation.py
index d9b7cc790e6..5f5d1ef7fd4 100644
--- a/tests/test_litellm/interactions/test_gemini_interactions_transformation.py
+++ b/tests/test_litellm/interactions/test_gemini_interactions_transformation.py
@@ -444,7 +444,12 @@ class TestStreamingIterator:
 
         text_event = self._make_text_delta("hi")
         completed = MagicMock(spec=ResponseCompletedEvent)
-        completed.response = MagicMock(id="resp_999")
+        # Create a proper mock response with usage attribute that has model_dump method
+        mock_response = MagicMock(id="resp_999")
+        mock_usage = MagicMock()
+        mock_usage.model_dump.return_value = {"input_tokens": 10, "output_tokens": 20, "total_tokens": 30}
+        mock_response.usage = mock_usage
+        completed.response = mock_response
 
         sync_iter = MagicMock()
         sync_iter.__iter__ = lambda self: self