Token usage not included in output when stream_mode includes “messages” #5951
Description
Checked other resources
- This is a bug, not a usage question. For questions, please use the LangChain Forum (https://forum.langchain.com/).
- I added a clear and detailed title that summarizes the issue.
- I read what a minimal reproducible example is (https://stackoverflow.com/help/minimal-reproducible-example).
- I included a self-contained, minimal example that demonstrates the issue INCLUDING all the relevant imports. The code run AS IS to reproduce the issue.
Example Code
from langgraph.prebuilt import create_react_agent
from databricks_langchain import ChatDatabricks
from langchain_core.callbacks import UsageMetadataCallbackHandler
from langchain_core.callbacks import get_usage_metadata_callback
agent = create_react_agent(
# using ChatDatabricks, tested with both Anthropic and OpenAI serving endpoints
model=ChatDatabricks(endpoint=os.getenv('LLM_ENDPOINT_PRIMARY'), temperature=0.0, stream_usage=True),
# tools=[get_weather],
tools=[],
prompt="You are a helpful assistant"
)
callback_handler = UsageMetadataCallbackHandler()
with get_usage_metadata_callback() as cb:
for event in agent.stream(
{"messages": [{"role": "user", "content": "hello!"}]},
config={"callbacks": [callback_handler]},
stream_mode=["updates"] # stream_mode=["updates","messages"]
):
print(event)Error Message and Stack Trace (if applicable)
Description
When streaming updates, the final update will include token usage information as expected:
AIMessage(content=‘Hello! How can I assist you today?’, additional_kwargs={}, response_metadata={‘created’: 1754669019, ‘id’: ‘chatcmpl-C2Jr93ePJ2iEdqo5K0hbcZNxtg7v2’, ‘model’: ‘gpt-4o-2024-08-06’, ‘object’: ‘chat.completion’, ‘system_fingerprint’: ‘fp_ee1d74bde0’, 'usage’: {‘completion_tokens’: 10, ‘completion_tokens_details’: {‘accepted_prediction_tokens’: 0, ‘audio_tokens’: 0, ‘reasoning_tokens’: 0, ‘rejected_prediction_tokens’: 0}, ‘prompt_tokens’: 18, ‘prompt_tokens_details’: {‘audio_tokens’: 0, ‘cached_tokens’: 0}, ‘total_tokens’: 28}, ‘model_name’: ‘gpt-4o-2024-08-06’}, id=‘run–ad5a92fc-fd7c-43b1-a3ff-f88c46da786a-0’)
However, if I use stream_mode=[“updates”, “messages”] neither the chunks nor the final update includes the usage information, the final update type output is now abbreviated to:
AIMessage(content=‘Hello! How can I assist you today?’, additional_kwargs={}, response_metadata={‘finish_reason’: ‘stop’}, id=‘run–bb73d7a0-e585-4938-8b18-609f7e50ccbc’)
I have tried included both CallbackHandler methods (as callback or as context manager), together (as above) and individually but neither is populated following the call to the endpoint. Adding "stream_usage=True" and calling an Anthropic endpoint and streaming messages will cause an error presumably because the token counts are None:
TypeError: unsupported operand type(s) for +: 'int' and 'NoneType'
Tested in Databricks serverless environment v2 with:
langgraph==0.5.3 and langgraph==0.6.4
databricks-lanchain==0.6.0
System Info
System Information
OS: Linux
OS Version: #1 SMP PREEMPT_DYNAMIC Wed Jul 2 02:54:28 UTC 2025
Python Version: 3.11.10 (main, Sep 7 2024, 18:35:41) [GCC 11.4.0]
Package Information
langchain_core: 0.3.74
langchain: 0.3.27
langchain_community: 0.3.27
langsmith: 0.4.13
langchain_openai: 0.3.29
langchain_text_splitters: 0.3.9
langgraph_chatagent: Installed. No version info available.
langgraph_sdk: 0.2.0
Optional packages not installed
langserve
Other Dependencies
aiohttp<4.0.0,>=3.8.3: Installed. No version info available.
async-timeout<5.0.0,>=4.0.0;: Installed. No version info available.
dataclasses-json<0.7,>=0.5.7: Installed. No version info available.
httpx-sse<1.0.0,>=0.4.0: Installed. No version info available.
httpx<1,>=0.23.0: Installed. No version info available.
httpx>=0.25.2: Installed. No version info available.
jsonpatch<2.0,>=1.33: Installed. No version info available.
langchain-anthropic;: Installed. No version info available.
langchain-aws;: Installed. No version info available.
langchain-azure-ai;: Installed. No version info available.
langchain-cohere;: Installed. No version info available.
langchain-community;: Installed. No version info available.
langchain-core<1.0.0,>=0.3.66: Installed. No version info available.
langchain-core<1.0.0,>=0.3.72: Installed. No version info available.
langchain-core<1.0.0,>=0.3.74: Installed. No version info available.
langchain-deepseek;: Installed. No version info available.
langchain-fireworks;: Installed. No version info available.
langchain-google-genai;: Installed. No version info available.
langchain-google-vertexai;: Installed. No version info available.
langchain-groq;: Installed. No version info available.
langchain-huggingface;: Installed. No version info available.
langchain-mistralai;: Installed. No version info available.
langchain-ollama;: Installed. No version info available.
langchain-openai;: Installed. No version info available.
langchain-perplexity;: Installed. No version info available.
langchain-text-splitters<1.0.0,>=0.3.9: Installed. No version info available.
langchain-together;: Installed. No version info available.
langchain-xai;: Installed. No version info available.
langchain<1.0.0,>=0.3.26: Installed. No version info available.
langsmith-pyo3>=0.1.0rc2;: Installed. No version info available.
langsmith>=0.1.125: Installed. No version info available.
langsmith>=0.1.17: Installed. No version info available.
langsmith>=0.3.45: Installed. No version info available.
numpy>=1.26.2;: Installed. No version info available.
numpy>=2.1.0;: Installed. No version info available.
openai-agents>=0.0.3;: Installed. No version info available.
openai<2.0.0,>=1.86.0: Installed. No version info available.
opentelemetry-api>=1.30.0;: Installed. No version info available.
opentelemetry-exporter-otlp-proto-http>=1.30.0;: Installed. No version info available.
opentelemetry-sdk>=1.30.0;: Installed. No version info available.
orjson>=3.10.1: Installed. No version info available.
orjson>=3.9.14;: Installed. No version info available.
packaging>=23.2: Installed. No version info available.
pydantic-settings<3.0.0,>=2.4.0: Installed. No version info available.
pydantic<3,>=1: Installed. No version info available.
pydantic<3.0.0,>=2.7.4: Installed. No version info available.
pydantic>=2.7.4: Installed. No version info available.
pytest>=7.0.0;: Installed. No version info available.
PyYAML>=5.3: Installed. No version info available.
requests-toolbelt>=1.0.0: Installed. No version info available.
requests<3,>=2: Installed. No version info available.
requests>=2.0.0: Installed. No version info available.
rich>=13.9.4;: Installed. No version info available.
SQLAlchemy<3,>=1.4: Installed. No version info available.
tenacity!=8.4.0,<10,>=8.1.0: Installed. No version info available.
tenacity!=8.4.0,<10.0.0,>=8.1.0: Installed. No version info available.
tiktoken<1,>=0.7: Installed. No version info available.
typing-extensions>=4.7: Installed. No version info available.
vcrpy>=7.0.0;: Installed. No version info available.
zstandard>=0.23.0: Installed. No version info available.