# LangGraph

LangGraph's `ToolNode` accepts the tools returned by these search constructors. If you restrict the available web or shopping engines, the agent is offered only those choices.


# Install

``` bash
pip install "serpapi-search-tools[langgraph]" langchain-openai
```

If LangGraph is already installed in your project, use `pip install serpapi-search-tools` instead.

The SerpApi extra installs the LangGraph and LangChain tool interfaces, while `langchain-openai` is the model backend selected by this example. Replace it when your graph uses another model provider.

``` bash
export SERPAPI_API_KEY="your-serpapi-key"
export OPENAI_API_KEY="your-openai-key"
```


# Run it

``` python
from langchain_openai import ChatOpenAI
from langgraph.graph import MessagesState, START, StateGraph
from langgraph.prebuilt import ToolNode, tools_condition
from serpapi_search_tools import web_search

search_tool = web_search()
model = ChatOpenAI(model="gpt-5.4-mini", temperature=0).bind_tools([search_tool])

def call_model(state: MessagesState):
    return {"messages": [model.invoke(state["messages"])]}

builder = StateGraph(MessagesState)
builder.add_node("model", call_model)
builder.add_node("tools", ToolNode([search_tool]))
builder.add_edge(START, "model")
builder.add_conditional_edges("model", tools_condition)
builder.add_edge("tools", "model")
agent = builder.compile()

result = agent.invoke(
    {"messages": [{"role": "user", "content": "Find recent Python packaging guidance."}]}
)
print(result)
```


# Try it

Ask: "Find recent Python packaging guidance and turn it into a five-item checklist."


# Customize the search

``` python
multi_source_search = web_search(
    allowed_engines=["google", "bing", "duckduckgo"],
    default_engine="google",
    result_limit=5,
)
```

The `langgraph` extra installs LangGraph 1.x and the LangChain tool interface used above. The OpenAI integration remains an application choice. Install the SDK extra separately from the Google ADK extra; their supported transitive dependency branches are incompatible.