From 3bf2e1841cf09231ab73a2f56edf01548005a7ba Mon Sep 17 00:00:00 2001
From: KnyazSh <yuriy.shuyskiy@gmail.com>
Date: Sun, 14 Jun 2026 11:27:37 +0000
Subject: [PATCH 1/2] fix(usage): correct calculate usage with cached tokens
 when use ChatCompletionUsageBlock

---
 .../streaming_chunk_builder_utils.py          |  2 +
 .../test_streaming_chunk_builder_utils.py     | 40 ++++++++++++++++++-
 2 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/litellm/litellm_core_utils/streaming_chunk_builder_utils.py b/litellm/litellm_core_utils/streaming_chunk_builder_utils.py
index b495b183ec06..d51b937d4341 100644
--- a/litellm/litellm_core_utils/streaming_chunk_builder_utils.py
+++ b/litellm/litellm_core_utils/streaming_chunk_builder_utils.py
@@ -604,6 +604,8 @@ def _calculate_usage_per_chunk(
                 usage_chunk = chunk._hidden_params.get("usage", None)
 
             if usage_chunk is not None:
+                if isinstance(usage_chunk, dict):
+                    usage_chunk = Usage(**usage_chunk)
                 usage_chunk_dict = self._usage_chunk_calculation_helper(usage_chunk)
                 if (
                     usage_chunk_dict["prompt_tokens"] is not None
diff --git a/tests/test_litellm/litellm_core_utils/test_streaming_chunk_builder_utils.py b/tests/test_litellm/litellm_core_utils/test_streaming_chunk_builder_utils.py
index c57941945285..248b2659a064 100644
--- a/tests/test_litellm/litellm_core_utils/test_streaming_chunk_builder_utils.py
+++ b/tests/test_litellm/litellm_core_utils/test_streaming_chunk_builder_utils.py
@@ -4,11 +4,13 @@
 
 import pytest
 
+from litellm.completion_extras.litellm_responses_transformation.transformation import GenericStreamingChunk
+
 sys.path.insert(
     0, os.path.abspath("../../..")
 )  # Adds the parent directory to the system path
 
-from litellm import stream_chunk_builder
+from litellm import ChatCompletionUsageBlock, stream_chunk_builder
 from litellm.litellm_core_utils.streaming_chunk_builder_utils import ChunkProcessor
 from litellm.types.utils import (
     ChatCompletionDeltaToolCall,
@@ -324,6 +326,42 @@ def test_cache_read_input_tokens_retained():
     assert usage.cache_read_input_tokens == 11775
     assert usage.prompt_tokens_details.cached_tokens == 11775
 
+def test_cache_read_input_tokens_retained_genericstreamingchunk():
+    chunk1 = GenericStreamingChunk(
+        text="Test1",
+        is_finished=False,
+        finish_reason="",
+        usage=None,
+        index=1,
+    )
+
+    chunk2 = GenericStreamingChunk(
+        text="Test2",
+        is_finished=True,
+        finish_reason="stop",
+        usage=ChatCompletionUsageBlock(
+            completion_tokens=5,
+            prompt_tokens=1234,
+            total_tokens=1239,
+            completion_tokens_details=None,
+            prompt_tokens_details=PromptTokensDetails(
+                audio_tokens=None, cached_tokens=543
+            ).model_dump(),
+        ),
+        index=2,
+    )
+
+    # Use dictionaries directly instead of ModelResponseStream
+    chunks = [chunk1, chunk2]
+    processor = ChunkProcessor(chunks=chunks)
+
+    usage = processor.calculate_usage(
+        chunks=chunks,
+        model="gpt-5.5",
+        completion_output="",
+    )
+
+    assert usage.prompt_tokens_details.cached_tokens == 543
 
 def test_stream_chunk_builder_litellm_usage_chunks():
     """

From 5a044284ad7859d1299ffc81670ca7f29bf2aef5 Mon Sep 17 00:00:00 2001
From: KnyazSh <yuriy.shuyskiy@gmail.com>
Date: Sun, 14 Jun 2026 12:28:56 +0000
Subject: [PATCH 2/2] fix(usage): optimize test imports

---
 .../litellm_core_utils/test_streaming_chunk_builder_utils.py   | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/tests/test_litellm/litellm_core_utils/test_streaming_chunk_builder_utils.py b/tests/test_litellm/litellm_core_utils/test_streaming_chunk_builder_utils.py
index 248b2659a064..b5eb7af88b38 100644
--- a/tests/test_litellm/litellm_core_utils/test_streaming_chunk_builder_utils.py
+++ b/tests/test_litellm/litellm_core_utils/test_streaming_chunk_builder_utils.py
@@ -4,13 +4,12 @@
 
 import pytest
 
-from litellm.completion_extras.litellm_responses_transformation.transformation import GenericStreamingChunk
-
 sys.path.insert(
     0, os.path.abspath("../../..")
 )  # Adds the parent directory to the system path
 
 from litellm import ChatCompletionUsageBlock, stream_chunk_builder
+from litellm.types.utils import GenericStreamingChunk
 from litellm.litellm_core_utils.streaming_chunk_builder_utils import ChunkProcessor
 from litellm.types.utils import (
     ChatCompletionDeltaToolCall,