langchain-ai/langgraph
1
0
Fork 0
mirror of https://github.com/langchain-ai/langgraph.git synced 2026-07-15 12:35:43 -04:00
Code Issues 314 Packages Projects Releases 17 Wiki Activity

When streaming using stream mode of messages I get token-by-token messages and full message at the end #977

New Issue
Closed
opened 2026-02-20 17:42:35 -05:00 by yindo · 2 comments
yindo commented 2026-02-20 17:42:35 -05:00
Owner
Copy Link
Copy Source

Originally created by @yaserabdelaziz on GitHub (Sep 16, 2025).

Originally assigned to: @casparb on GitHub.

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

for chunk_item in self.graph.stream(
    initial_state, config, stream_mode="messages"
):

Error Message and Stack Trace (if applicable)

Stream chunk: content=[{'type': 'text', 'text': ' HVAC Technical Support Resources', 'index': 0}] additional_kwargs={} response_metadata={} id='run--86d8f139-51d7-4b92-858b-dbc10a7f8fc2'
Stream metadata: {'thread_id': 'f92c93c9-9830-4473-a938-594d50409ba0', 'recursion_limit': 4, 'langgraph_step': 2, 'langgraph_node': 'final_answer', 'langgraph_triggers': ('branch:to:final_answer',), 'langgraph_path': ('__pregel_pull', 'final_answer'), 'langgraph_checkpoint_ns': 'final_answer:9ff545d7-9d6e-e89a-45df-05399c132c94', 'checkpoint_ns': 'final_answer:9ff545d7-9d6e-e89a-45df-05399c132c94', 'ls_provider': 'amazon_bedrock', 'ls_model_name': 'us.meta.llama4-maverick-17b-instruct-v1:0', 'ls_model_type': 'chat', 'ls_max_tokens': 8192}
Stream chunk: content=[{'type': 'text', 'text': '', 'index': 0}] additional_kwargs={} response_metadata={} id='run--86d8f139-51d7-4b92-858b-dbc10a7f8fc2'
Stream metadata: {'thread_id': 'f92c93c9-9830-4473-a938-594d50409ba0', 'recursion_limit': 4, 'langgraph_step': 2, 'langgraph_node': 'final_answer', 'langgraph_triggers': ('branch:to:final_answer',), 'langgraph_path': ('__pregel_pull', 'final_answer'), 'langgraph_checkpoint_ns': 'final_answer:9ff545d7-9d6e-e89a-45df-05399c132c94', 'checkpoint_ns': 'final_answer:9ff545d7-9d6e-e89a-45df-05399c132c94', 'ls_provider': 'amazon_bedrock', 'ls_model_name': 'us.meta.llama4-maverick-17b-instruct-v1:0', 'ls_model_type': 'chat', 'ls_max_tokens': 8192}
Stream chunk: content=[{'index': 0}] additional_kwargs={} response_metadata={} id='run--86d8f139-51d7-4b92-858b-dbc10a7f8fc2'
Stream metadata: {'thread_id': 'f92c93c9-9830-4473-a938-594d50409ba0', 'recursion_limit': 4, 'langgraph_step': 2, 'langgraph_node': 'final_answer', 'langgraph_triggers': ('branch:to:final_answer',), 'langgraph_path': ('__pregel_pull', 'final_answer'), 'langgraph_checkpoint_ns': 'final_answer:9ff545d7-9d6e-e89a-45df-05399c132c94', 'checkpoint_ns': 'final_answer:9ff545d7-9d6e-e89a-45df-05399c132c94', 'ls_provider': 'amazon_bedrock', 'ls_model_name': 'us.meta.llama4-maverick-17b-instruct-v1:0', 'ls_model_type': 'chat', 'ls_max_tokens': 8192}
Stream chunk: content=[] additional_kwargs={} response_metadata={'stopReason': 'end_turn'} id='run--86d8f139-51d7-4b92-858b-dbc10a7f8fc2'
Stream metadata: {'thread_id': 'f92c93c9-9830-4473-a938-594d50409ba0', 'recursion_limit': 4, 'langgraph_step': 2, 'langgraph_node': 'final_answer', 'langgraph_triggers': ('branch:to:final_answer',), 'langgraph_path': ('__pregel_pull', 'final_answer'), 'langgraph_checkpoint_ns': 'final_answer:9ff545d7-9d6e-e89a-45df-05399c132c94', 'checkpoint_ns': 'final_answer:9ff545d7-9d6e-e89a-45df-05399c132c94', 'ls_provider': 'amazon_bedrock', 'ls_model_name': 'us.meta.llama4-maverick-17b-instruct-v1:0', 'ls_model_type': 'chat', 'ls_max_tokens': 8192}
Stream chunk: content=[] additional_kwargs={} response_metadata={'metrics': {'latencyMs': 1047}, 'model_name': 'us.meta.llama4-maverick-17b-instruct-v1:0', 'ResponseMetadata': {'RequestId': '4de582bd-9e16-4a7b-9cca-e61d59a98b10', 'HTTPStatusCode': 200, 'HTTPHeaders': {'date': 'Tue, 16 Sep 2025 12:45:19 GMT', 'content-type': 'application/vnd.amazon.eventstream', 'transfer-encoding': 'chunked', 'connection': 'keep-alive', 'x-amzn-requestid': '4de582bd-9e16-4a7b-9cca-e61d59a98b10'}, 'RetryAttempts': 0}} id='run--86d8f139-51d7-4b92-858b-dbc10a7f8fc2' usage_metadata={'input_tokens': 1001, 'output_tokens': 46, 'total_tokens': 1047, 'input_token_details': {'cache_creation': 0, 'cache_read': 0}}
Stream metadata: {'thread_id': 'f92c93c9-9830-4473-a938-594d50409ba0', 'recursion_limit': 4, 'langgraph_step': 2, 'langgraph_node': 'final_answer', 'langgraph_triggers': ('branch:to:final_answer',), 'langgraph_path': ('__pregel_pull', 'final_answer'), 'langgraph_checkpoint_ns': 'final_answer:9ff545d7-9d6e-e89a-45df-05399c132c94', 'checkpoint_ns': 'final_answer:9ff545d7-9d6e-e89a-45df-05399c132c94', 'ls_provider': 'amazon_bedrock', 'ls_model_name': 'us.meta.llama4-maverick-17b-instruct-v1:0', 'ls_model_type': 'chat', 'ls_max_tokens': 8192}
Stream chunk: content=[{'type': 'text', 'text': "Hello Gandalf! Welcome to Carrier HVAC technical support. I'm here to help with any questions or issues you have regarding your Carrier equipment. What can I assist you with today?\n\n# References\n1. Carrier HVAC Technical Support Resources", 'index': 0}] additional_kwargs={} response_metadata={} id='4699525b-4551-413c-991f-8a82fe7fc95c'
Stream metadata: {'thread_id': 'f92c93c9-9830-4473-a938-594d50409ba0', 'recursion_limit': 4, 'langgraph_step': 2, 'langgraph_node': 'final_answer', 'langgraph_triggers': ('branch:to:final_answer',), 'langgraph_path': ('__pregel_pull', 'final_answer'), 'langgraph_checkpoint_ns': 'final_answer:9ff545d7-9d6e-e89a-45df-05399c132c94'}

Description

When streaming using stream mode of messages I get token-by-token messages and full message at the end. In the past versions I was only having token-by-token messages. The full message at the end adds redundancy.

System Info

System Information

OS: Linux
OS Version: #1 SMP PREEMPT_DYNAMIC Thu Jun 5 18:30:46 UTC 2025
Python Version: 3.12.11 (main, Sep 2 2025, 14:20:58) [Clang 20.1.4 ]

Package Information

langchain_core: 0.3.75
langchain: 0.3.27
langchain_community: 0.3.21
langsmith: 0.3.45
langchain_aws: 0.2.31
langchain_mcp_adapters: 0.1.9
langchain_mongodb: 0.7.0
langchain_openai: 0.3.32
langchain_text_splitters: 0.3.11
langgraph_sdk: 0.2.6

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.
beautifulsoup4: Installed. No version info available.
bedrock-agentcore: Installed. No version info available.
boto3: 1.39.11
dataclasses-json<0.7,>=0.5.7: Installed. No version info available.
httpx: 0.27.2
httpx-sse<1.0.0,>=0.4.0: 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<0.4,>=0.3.36: Installed. No version info available.
langchain-core<1.0.0,>=0.3.51: 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-core<2.0.0,>=0.3.75: Installed. No version info available.
langchain-core>=0.3: 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-text-splitters>=0.3: Installed. No version info available.
langchain-together;: Installed. No version info available.
langchain-xai;: Installed. No version info available.
langchain<1.0.0,>=0.3.23: Installed. No version info available.
langchain>=0.3: Installed. No version info available.
langsmith-pyo3: Installed. No version info available.
langsmith<0.4,>=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.
lark<2.0.0,>=1.1.9: Installed. No version info available.
mcp>=1.9.2: Installed. No version info available.
numpy: 1.26.4
numpy<3,>=1.26.2: Installed. No version info available.
numpy>=1.26: Installed. No version info available.
openai-agents: Installed. No version info available.
openai<2.0.0,>=1.99.9: Installed. No version info available.
opentelemetry-api: 1.36.0
opentelemetry-exporter-otlp-proto-http: 1.36.0
opentelemetry-sdk: 1.36.0
orjson: 3.11.3
orjson>=3.10.1: Installed. No version info available.
packaging: 24.2
packaging>=23.2: Installed. No version info available.
playwright: Installed. No version info available.
pydantic: 2.11.7
pydantic-settings<3.0.0,>=2.4.0: 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.
pymongo>=4.6.1: Installed. No version info available.
pytest: 8.3.3
PyYAML>=5.3: Installed. No version info available.
requests: 2.32.5
requests-toolbelt: 1.0.0
requests<3,>=2: Installed. No version info available.
rich: 13.9.4
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>=4.14.0: Installed. No version info available.
typing-extensions>=4.7: Installed. No version info available.
zstandard: 0.23.0

Originally created by @yaserabdelaziz on GitHub (Sep 16, 2025). Originally assigned to: @casparb on GitHub. ### Checked other resources - [x] This is a bug, not a usage question. For questions, please use the LangChain Forum (https://forum.langchain.com/). - [x] I added a clear and detailed title that summarizes the issue. - [x] I read what a minimal reproducible example is (https://stackoverflow.com/help/minimal-reproducible-example). - [x] 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 ```python for chunk_item in self.graph.stream( initial_state, config, stream_mode="messages" ): ``` ### Error Message and Stack Trace (if applicable) ```shell Stream chunk: content=[{'type': 'text', 'text': ' HVAC Technical Support Resources', 'index': 0}] additional_kwargs={} response_metadata={} id='run--86d8f139-51d7-4b92-858b-dbc10a7f8fc2' Stream metadata: {'thread_id': 'f92c93c9-9830-4473-a938-594d50409ba0', 'recursion_limit': 4, 'langgraph_step': 2, 'langgraph_node': 'final_answer', 'langgraph_triggers': ('branch:to:final_answer',), 'langgraph_path': ('__pregel_pull', 'final_answer'), 'langgraph_checkpoint_ns': 'final_answer:9ff545d7-9d6e-e89a-45df-05399c132c94', 'checkpoint_ns': 'final_answer:9ff545d7-9d6e-e89a-45df-05399c132c94', 'ls_provider': 'amazon_bedrock', 'ls_model_name': 'us.meta.llama4-maverick-17b-instruct-v1:0', 'ls_model_type': 'chat', 'ls_max_tokens': 8192} Stream chunk: content=[{'type': 'text', 'text': '', 'index': 0}] additional_kwargs={} response_metadata={} id='run--86d8f139-51d7-4b92-858b-dbc10a7f8fc2' Stream metadata: {'thread_id': 'f92c93c9-9830-4473-a938-594d50409ba0', 'recursion_limit': 4, 'langgraph_step': 2, 'langgraph_node': 'final_answer', 'langgraph_triggers': ('branch:to:final_answer',), 'langgraph_path': ('__pregel_pull', 'final_answer'), 'langgraph_checkpoint_ns': 'final_answer:9ff545d7-9d6e-e89a-45df-05399c132c94', 'checkpoint_ns': 'final_answer:9ff545d7-9d6e-e89a-45df-05399c132c94', 'ls_provider': 'amazon_bedrock', 'ls_model_name': 'us.meta.llama4-maverick-17b-instruct-v1:0', 'ls_model_type': 'chat', 'ls_max_tokens': 8192} Stream chunk: content=[{'index': 0}] additional_kwargs={} response_metadata={} id='run--86d8f139-51d7-4b92-858b-dbc10a7f8fc2' Stream metadata: {'thread_id': 'f92c93c9-9830-4473-a938-594d50409ba0', 'recursion_limit': 4, 'langgraph_step': 2, 'langgraph_node': 'final_answer', 'langgraph_triggers': ('branch:to:final_answer',), 'langgraph_path': ('__pregel_pull', 'final_answer'), 'langgraph_checkpoint_ns': 'final_answer:9ff545d7-9d6e-e89a-45df-05399c132c94', 'checkpoint_ns': 'final_answer:9ff545d7-9d6e-e89a-45df-05399c132c94', 'ls_provider': 'amazon_bedrock', 'ls_model_name': 'us.meta.llama4-maverick-17b-instruct-v1:0', 'ls_model_type': 'chat', 'ls_max_tokens': 8192} Stream chunk: content=[] additional_kwargs={} response_metadata={'stopReason': 'end_turn'} id='run--86d8f139-51d7-4b92-858b-dbc10a7f8fc2' Stream metadata: {'thread_id': 'f92c93c9-9830-4473-a938-594d50409ba0', 'recursion_limit': 4, 'langgraph_step': 2, 'langgraph_node': 'final_answer', 'langgraph_triggers': ('branch:to:final_answer',), 'langgraph_path': ('__pregel_pull', 'final_answer'), 'langgraph_checkpoint_ns': 'final_answer:9ff545d7-9d6e-e89a-45df-05399c132c94', 'checkpoint_ns': 'final_answer:9ff545d7-9d6e-e89a-45df-05399c132c94', 'ls_provider': 'amazon_bedrock', 'ls_model_name': 'us.meta.llama4-maverick-17b-instruct-v1:0', 'ls_model_type': 'chat', 'ls_max_tokens': 8192} Stream chunk: content=[] additional_kwargs={} response_metadata={'metrics': {'latencyMs': 1047}, 'model_name': 'us.meta.llama4-maverick-17b-instruct-v1:0', 'ResponseMetadata': {'RequestId': '4de582bd-9e16-4a7b-9cca-e61d59a98b10', 'HTTPStatusCode': 200, 'HTTPHeaders': {'date': 'Tue, 16 Sep 2025 12:45:19 GMT', 'content-type': 'application/vnd.amazon.eventstream', 'transfer-encoding': 'chunked', 'connection': 'keep-alive', 'x-amzn-requestid': '4de582bd-9e16-4a7b-9cca-e61d59a98b10'}, 'RetryAttempts': 0}} id='run--86d8f139-51d7-4b92-858b-dbc10a7f8fc2' usage_metadata={'input_tokens': 1001, 'output_tokens': 46, 'total_tokens': 1047, 'input_token_details': {'cache_creation': 0, 'cache_read': 0}} Stream metadata: {'thread_id': 'f92c93c9-9830-4473-a938-594d50409ba0', 'recursion_limit': 4, 'langgraph_step': 2, 'langgraph_node': 'final_answer', 'langgraph_triggers': ('branch:to:final_answer',), 'langgraph_path': ('__pregel_pull', 'final_answer'), 'langgraph_checkpoint_ns': 'final_answer:9ff545d7-9d6e-e89a-45df-05399c132c94', 'checkpoint_ns': 'final_answer:9ff545d7-9d6e-e89a-45df-05399c132c94', 'ls_provider': 'amazon_bedrock', 'ls_model_name': 'us.meta.llama4-maverick-17b-instruct-v1:0', 'ls_model_type': 'chat', 'ls_max_tokens': 8192} Stream chunk: content=[{'type': 'text', 'text': "Hello Gandalf! Welcome to Carrier HVAC technical support. I'm here to help with any questions or issues you have regarding your Carrier equipment. What can I assist you with today?\n\n# References\n1. Carrier HVAC Technical Support Resources", 'index': 0}] additional_kwargs={} response_metadata={} id='4699525b-4551-413c-991f-8a82fe7fc95c' Stream metadata: {'thread_id': 'f92c93c9-9830-4473-a938-594d50409ba0', 'recursion_limit': 4, 'langgraph_step': 2, 'langgraph_node': 'final_answer', 'langgraph_triggers': ('branch:to:final_answer',), 'langgraph_path': ('__pregel_pull', 'final_answer'), 'langgraph_checkpoint_ns': 'final_answer:9ff545d7-9d6e-e89a-45df-05399c132c94'} ``` ### Description When streaming using stream mode of messages I get token-by-token messages and full message at the end. In the past versions I was only having token-by-token messages. The full message at the end adds redundancy. ### System Info System Information ------------------ > OS: Linux > OS Version: #1 SMP PREEMPT_DYNAMIC Thu Jun 5 18:30:46 UTC 2025 > Python Version: 3.12.11 (main, Sep 2 2025, 14:20:58) [Clang 20.1.4 ] Package Information ------------------- > langchain_core: 0.3.75 > langchain: 0.3.27 > langchain_community: 0.3.21 > langsmith: 0.3.45 > langchain_aws: 0.2.31 > langchain_mcp_adapters: 0.1.9 > langchain_mongodb: 0.7.0 > langchain_openai: 0.3.32 > langchain_text_splitters: 0.3.11 > langgraph_sdk: 0.2.6 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. > beautifulsoup4: Installed. No version info available. > bedrock-agentcore: Installed. No version info available. > boto3: 1.39.11 > dataclasses-json<0.7,>=0.5.7: Installed. No version info available. > httpx: 0.27.2 > httpx-sse<1.0.0,>=0.4.0: 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<0.4,>=0.3.36: Installed. No version info available. > langchain-core<1.0.0,>=0.3.51: 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-core<2.0.0,>=0.3.75: Installed. No version info available. > langchain-core>=0.3: 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-text-splitters>=0.3: Installed. No version info available. > langchain-together;: Installed. No version info available. > langchain-xai;: Installed. No version info available. > langchain<1.0.0,>=0.3.23: Installed. No version info available. > langchain>=0.3: Installed. No version info available. > langsmith-pyo3: Installed. No version info available. > langsmith<0.4,>=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. > lark<2.0.0,>=1.1.9: Installed. No version info available. > mcp>=1.9.2: Installed. No version info available. > numpy: 1.26.4 > numpy<3,>=1.26.2: Installed. No version info available. > numpy>=1.26: Installed. No version info available. > openai-agents: Installed. No version info available. > openai<2.0.0,>=1.99.9: Installed. No version info available. > opentelemetry-api: 1.36.0 > opentelemetry-exporter-otlp-proto-http: 1.36.0 > opentelemetry-sdk: 1.36.0 > orjson: 3.11.3 > orjson>=3.10.1: Installed. No version info available. > packaging: 24.2 > packaging>=23.2: Installed. No version info available. > playwright: Installed. No version info available. > pydantic: 2.11.7 > pydantic-settings<3.0.0,>=2.4.0: 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. > pymongo>=4.6.1: Installed. No version info available. > pytest: 8.3.3 > PyYAML>=5.3: Installed. No version info available. > requests: 2.32.5 > requests-toolbelt: 1.0.0 > requests<3,>=2: Installed. No version info available. > rich: 13.9.4 > 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>=4.14.0: Installed. No version info available. > typing-extensions>=4.7: Installed. No version info available. > zstandard: 0.23.0
yindo added the question label 2026-02-20 17:42:35 -05:00
yindo closed this issue 2026-02-20 17:42:35 -05:00
yindo commented 2026-02-20 17:42:36 -05:00
Author
Owner
Copy Link
Copy Source

@casparb commented on GitHub (Sep 17, 2025):

Hi @yaserabdelaziz, not sure what you mean. I can setup a simple graph:

from typing_extensions import TypedDict
from langgraph.graph import StateGraph, START, END
from langchain_core.messages import AnyMessage, HumanMessage
from langchain_openai import ChatOpenAI

class State(TypedDict):
    messages: list[AnyMessage]

llm = ChatOpenAI(model="gpt-4o")

def final_answer(state: State):
    resp = llm.invoke(state["messages"])
    return {"messages": [resp]}

builder = StateGraph(State)
builder.add_node("final_answer", final_answer)
builder.add_edge(START, "final_answer")
builder.add_edge("final_answer", END)
graph = builder.compile()

initial = {"messages": [HumanMessage(content="Reply with a short greeting, streaming tokens.")]}

for message, meta in graph.stream(initial, stream_mode="messages"):
    print("Stream chunk:", message)

Only the chunks are streamed, not a final message:

Stream chunk: content='' additional_kwargs={} response_metadata={} id='run--fa51ea5e-c308-4230-8925-f09085dd0303'
Stream chunk: content='Hello' additional_kwargs={} response_metadata={} id='run--fa51ea5e-c308-4230-8925-f09085dd0303'
Stream chunk: content=' there' additional_kwargs={} response_metadata={} id='run--fa51ea5e-c308-4230-8925-f09085dd0303'
Stream chunk: content='!' additional_kwargs={} response_metadata={} id='run--fa51ea5e-c308-4230-8925-f09085dd0303'
Stream chunk: content='' additional_kwargs={} response_metadata={'finish_reason': 'stop', 'model_name': 'gpt-4o-2024-08-06', 'system_fingerprint': 'fp_f33640a400', 'service_tier': 'default'} id='run--fa51ea5e-c308-4230-8925-f09085dd0303'

Our docs on streaming LLM tokens might help clear things up.

Closing as I can't help much without knowing what your graph looks like. Provide a MRE and I'd be happy to reopen.

@casparb commented on GitHub (Sep 17, 2025): Hi @yaserabdelaziz, not sure what you mean. I can setup a simple graph: ```python from typing_extensions import TypedDict from langgraph.graph import StateGraph, START, END from langchain_core.messages import AnyMessage, HumanMessage from langchain_openai import ChatOpenAI class State(TypedDict): messages: list[AnyMessage] llm = ChatOpenAI(model="gpt-4o") def final_answer(state: State): resp = llm.invoke(state["messages"]) return {"messages": [resp]} builder = StateGraph(State) builder.add_node("final_answer", final_answer) builder.add_edge(START, "final_answer") builder.add_edge("final_answer", END) graph = builder.compile() initial = {"messages": [HumanMessage(content="Reply with a short greeting, streaming tokens.")]} for message, meta in graph.stream(initial, stream_mode="messages"): print("Stream chunk:", message) ``` Only the chunks are streamed, not a final message: ``` Stream chunk: content='' additional_kwargs={} response_metadata={} id='run--fa51ea5e-c308-4230-8925-f09085dd0303' Stream chunk: content='Hello' additional_kwargs={} response_metadata={} id='run--fa51ea5e-c308-4230-8925-f09085dd0303' Stream chunk: content=' there' additional_kwargs={} response_metadata={} id='run--fa51ea5e-c308-4230-8925-f09085dd0303' Stream chunk: content='!' additional_kwargs={} response_metadata={} id='run--fa51ea5e-c308-4230-8925-f09085dd0303' Stream chunk: content='' additional_kwargs={} response_metadata={'finish_reason': 'stop', 'model_name': 'gpt-4o-2024-08-06', 'system_fingerprint': 'fp_f33640a400', 'service_tier': 'default'} id='run--fa51ea5e-c308-4230-8925-f09085dd0303' ``` Our docs on [streaming LLM tokens](https://docs.langchain.com/oss/python/langgraph/streaming#llm-tokens) might help clear things up. Closing as I can't help much without knowing what your graph looks like. Provide a MRE and I'd be happy to reopen.
yindo commented 2026-02-20 17:42:36 -05:00
Author
Owner
Copy Link
Copy Source

@kvpratama commented on GitHub (Dec 26, 2025):

I ran into the same issue and tracked down the cause:

response = llm.invoke(messages)
# ❌ This recreates a new AIMessage, which causes the final complete message to be emitted again
return {
    "messages": [AIMessage(content=response.content, name="customer_service")]
}

The solution is to return the original response object from the LLM instead:

response = llm.invoke(messages)
# ✅ This only streams chunks, no duplicate complete message
return {
    "messages": [response]
}

From what I can tell, LangGraph seems to track messages by their ID. My guess is that by recreating a new AIMessage, it ends up with a different ID than the streamed chunks, so LangGraph treats it as new content and emits it again.

@kvpratama commented on GitHub (Dec 26, 2025): I ran into the same issue and tracked down the cause: ```python response = llm.invoke(messages) # ❌ This recreates a new AIMessage, which causes the final complete message to be emitted again return { "messages": [AIMessage(content=response.content, name="customer_service")] } ``` The solution is to return the **original response object** from the LLM instead: ```python response = llm.invoke(messages) # ✅ This only streams chunks, no duplicate complete message return { "messages": [response] } ``` From what I can tell, LangGraph seems to track messages by their ID. My guess is that by recreating a new AIMessage, it ends up with a different ID than the streamed chunks, so LangGraph treats it as new content and emits it again.
Sign in to join this conversation.
No Branch/Tag Specified
Branches Tags
Labels
Clear labels
agents
awaiting author revision
bug
change
chat models
checkpointer
ci
code quality
code quality
dependencies
documentation
drawing
duplicate
enhancement
good first issue
help wanted
invalid
maintainer
meta
missing information
not maintained by langchain
open-swe-auto
open-swe-max
open-swe-max-auto
pending
performance
pull-request
Mirrored from GitHub Pull Request
 question
requires design
sdk
server
stale
studio
tests
type checking
usage question
v0.5
v1.1
No Label question
Milestone
No items
No Milestone
Projects
Clear projects
No project
Assignees
Clear assignees
yindo
No Assignees
1 Participants
Notifications
Due Date
No due date set.
Dependencies

No dependencies set.

Reference: langchain-ai/langgraph#977
Delete Branch "%!s()"

Deleting a branch is permanent. Although the deleted branch may continue to exist for a short time before it actually gets removed, it CANNOT be undone in most cases. Continue?