When tools are bound in the `create_agent` function, the deepseek-reasoner model cannot return `reasoning_content`.

[cloud-java]

Checked other resources

• This is a bug, not a usage question.
• I added a clear and descriptive title that summarizes this issue.
• I used the GitHub search to find a similar question and didn't find it.
• I am sure that this is a bug in LangChain rather than my code.
• The bug is not resolved by updating to the latest stable version of LangChain (or the specific integration package).
• This is not related to the langchain-community package.
• I posted a self-contained, minimal, reproducible example. A maintainer can copy it and run it AS IS.

Package (Required)

• langchain
• langchain-openai
• langchain-anthropic
• langchain-classic
• langchain-core
• langchain-cli
• langchain-model-profiles
• langchain-tests
• langchain-text-splitters
• langchain-chroma
• langchain-deepseek
• langchain-exa
• langchain-fireworks
• langchain-groq
• langchain-huggingface
• langchain-mistralai
• langchain-nomic
• langchain-ollama
• langchain-perplexity
• langchain-prompty
• langchain-qdrant
• langchain-xai
• Other / not sure / general

Example Code (Python)

# pip install -qU "langchain[anthropic]" to call the model
import os

from dotenv import load_dotenv
from langchain.agents import create_agent
load_dotenv()
os.environ["DEEPSEEK_API_KEY"] = os.getenv("DEEPSEEK_API_KEY")


def get_weather(city: str) -> str:
    """Get weather for a given city."""
    return f"It's always sunny in {city}!"


from langchain.chat_models import init_chat_model
from langchain_deepseek import ChatDeepSeek

model = init_chat_model(
    "deepseek-reasoner",
)
agent = create_agent(
    model=model,
    # When tools are bound in the `create_agent` function, 
    # the deepseek-reasoner model cannot return `reasoning_content`.
    tools=[get_weather],
    system_prompt="You are a helpful assistant",
)
for chunk in agent.stream(
        {"messages": [{"role": "user", "content": "hi"}]},
        stream_mode="messages",
):
    print(chunk)

Error Message and Stack Trace (if applicable)

/test-langchain-v1/.venv/bin/python /Users/java0904/test-langchain-v1/main.py 
(AIMessageChunk(content='', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content='Hello', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content='!', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' How', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' can', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' I', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' help', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' you', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' today', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content='?', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' I', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content="'m", additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' here', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' to', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' assist', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' you', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' with', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' various', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' tasks', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=',', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' including', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' checking', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' weather', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' information', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' for', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' any', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' city', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' you', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content="'re", additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' interested', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' in', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content='.', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' What', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' would', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' you', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' like', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' to', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content=' know', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content='?', additional_kwargs={}, response_metadata={'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})
(AIMessageChunk(content='', additional_kwargs={}, response_metadata={'finish_reason': 'stop', 'model_name': 'deepseek-chat', 'system_fingerprint': 'fp_ffc7281d48_prod0820_fp8_kvcache', 'model_provider': 'deepseek'}, id='lc_run--fc0ce7ef-ef72-46c3-97b4-1bcd2c0cff38', usage_metadata={'input_tokens': 153, 'output_tokens': 38, 'total_tokens': 191, 'input_token_details': {'cache_read': 128}, 'output_token_details': {}}, chunk_position='last'), {'langgraph_step': 1, 'langgraph_node': 'model', 'langgraph_triggers': ('branch:to:model',), 'langgraph_path': ('__pregel_pull', 'model'), 'langgraph_checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'checkpoint_ns': 'model:49e50315-7ba6-83c6-09f5-ca7712273856', 'ls_provider': 'deepseek', 'ls_model_name': 'deepseek-reasoner', 'ls_model_type': 'chat', 'ls_temperature': None})

Process finished with exit code 0

Description

when I use this function

agent = create_agent(
    model=model,
    # When tools are bound in the `create_agent` function,
    # the deepseek-reasoner model cannot return `reasoning_content`.
    tools=[get_weather],
    system_prompt="You are a helpful assistant",
)

I except the reasoning_content will return ,but it dose not work,unless I remove the tools

System Info

pip install -qU "langchain[anthropic]" to call the model

import os

from dotenv import load_dotenv
from langchain.agents import create_agent
load_dotenv()
os.environ["DEEPSEEK_API_KEY"] = os.getenv("DEEPSEEK_API_KEY")

def get_weather(city: str) -> str:
"""Get weather for a given city."""
return f"It's always sunny in {city}!"

from langchain.chat_models import init_chat_model
from langchain_deepseek import ChatDeepSeek

model = init_chat_model(
"deepseek-reasoner",
)
agent = create_agent(
model=model,
# When tools are bound in the create_agent function,
# the deepseek-reasoner model cannot return reasoning_content.
tools=[get_weather],
system_prompt="You are a helpful assistant",
)
for chunk in agent.stream(
{"messages": [{"role": "user", "content": "hi"}]},
stream_mode="messages",
):
print(chunk)

[FrankHui]

is your langchain version > 1.0.0？
Mine is 1.0.5. And according to GPT, this version no more supports thought of chain. Instead, new version is of OpenAI/Function style which doesn't store reasoning process in msg.content.

I'm wondering it's true. If true, why?

[wankaiyi]

Outputting reasoning_content is not allowed in function calling mode.

[wankaiyi]

Outputting reasoning_content is not allowed in function calling mode.函数调用模式下不允许输出 reasoning_content。

see https://api-docs.deepseek.com/guides/reasoning_model
Not Supported Features：Function Calling、FIM (Beta)

[FrankHui]

Outputting reasoning_content is not allowed in function calling mode.函数调用模式下不允许输出 reasoning_content。

see https://api-docs.deepseek.com/guides/reasoning_model Not Supported Features：Function Calling、FIM (Beta)

i use claude. and it also doesn't support output reasoning when function calling. i guess it's some kind of general feature. maybe this feature make function calling more stable or save tokens?

[wankaiyi]

Outputting reasoning_content is not allowed in function calling mode.函数调用模式下不允许输出 reasoning_content。函数调用模式下不允许输出 reasoning_content。函数调用模式下不允许输出 reasoning_content。

see https://api-docs.deepseek.com/guides/reasoning_model Not Supported Features：Function Calling、FIM (Beta)请参阅 https://api-docs.deepseek.com/guides/reasoning_model 不支持的功能：函数调用、FIM（测试版）

i use claude. and it also doesn't support output reasoning when function calling. i guess it's some kind of general feature. maybe this feature make function calling more stable or save tokens?我用的是 Claude，它也不支持函数调用时的输出推理。我猜这是某种通用特性。也许这个特性能让函数调用更稳定或者节省令牌？

Perhaps. I suspect it might be due to a conflict between the output of function calling and reasoning. OpenAI's reasoning model could be used if needed.