NeMo Relay LangGraph Integration

Use the nemo_relay.integrations.langgraph package to add NeMo Relay observability to LangGraph workflows through public LangGraph APIs.

Setup

Install the LangGraph integration extra in your application environment.

uv

pip

uv add "nemo-relay[langgraph]"

Installing the langgraph extra also installs the LangChain integration dependencies.

Usage Example

from typing_extensions import TypedDict
import nemo_relay
from langgraph.graph import END, START, StateGraph
from nemo_relay.integrations.langgraph import NemoRelayCallbackHandler
class State(TypedDict):
    value: int
def increment(state: State) -> State:
    return {"value": state["value"] + 1}
builder = StateGraph(State)
builder.add_node("increment", increment)
builder.add_edge(START, "increment")
builder.add_edge("increment", END)
graph = builder.compile()
with nemo_relay.scope.scope("langgraph-request", nemo_relay.ScopeType.Agent):
    result = graph.invoke(
        {"value": 1},
        config={"callbacks": [NemoRelayCallbackHandler()]},
    )
print(result)

For LangChain agents inside a LangGraph workflow, use NemoRelayMiddleware from this package the same way as the LangChain integration and pass the LangGraph config into the nested agent call:

from langchain.agents import create_agent
from langchain_core.runnables import RunnableConfig
from nemo_relay.integrations.langgraph import NemoRelayMiddleware
agent = create_agent(
    model="nvidia:nvidia/nemotron-3-nano-30b-a3b",
    tools=[],
    middleware=[NemoRelayMiddleware()],
)
def agent_node(state: dict, config: RunnableConfig) -> dict:
    return agent.invoke({"messages": state["messages"]}, config=config)

Install the NVIDIA LangChain provider if you want to run the nested agent example as written:

uv

pip

uv add "nemo-relay[langgraph,langchain-nvidia]"

Verify the Integration

The integration works correctly when:

graph.invoke(...) returns the incremented state from the example.
The langgraph-request scope contains the LangGraph run.
Nested LangChain agents inherit the same callback config when you pass the LangGraph config through.

Observability

Refer to Observability for details on exporting NeMo Relay observability data to third-party systems.