LangGraph Tracing

Phoenix has first-class support for LangGraph applications.

LangGraph is supported by our LangChain instrumentor. If you've already set up instrumentation with LangChain, you don't need to complete the set up below

Launch Phoenix

Install

pip install openinference-instrumentation-langchain

Install the OpenInference Langchain library before your application code. Our LangChainInstrumentor works for both standard LangChain applications and for LangGraph agents.

Setup

Use the register function to connect your application to Phoenix:

from phoenix.otel import register

# configure the Phoenix tracer
tracer_provider = register(
  project_name="my-llm-app", # Default is 'default'
  auto_instrument=True # Auto-instrument your app based on installed OI dependencies
)

Run LangGraph

By instrumenting LangGraph, spans will be created whenever an agent is invoked and will be sent to the Phoenix server for collection.

Observe

Now that you have tracing setup, all invocations of chains will be streamed to your running Phoenix for observability and evaluation.

Resources

• Example notebook

• OpenInference package

• Blog walkthrough