langchain/docs/tracing/langchain_plus_client.md

LangChain Plus Client

The LangChainPlusClient is useful for interacting with a tracing server. This guide explains how to make the client, how to connect to the server, and some of functionality it enables. For more information on using the client to evaluate agents on Datasets, check out our Datasets guide.

This guide assumes you already have a hosted account or are running the locally hosted tracing server.

Installation

The LangChainPlusClient is included as a part of your langchain installation. To install or upgrade, run:

pip install -U langchain

Creating LangChainPlusClient

The LangChainPlusClient connects to the tracing server's REST API. To create a client:

# import os
# os.environ["LANGCHAIN_ENDPOINT"] = "https://api.langchain.plus"  # Uncomment this line if you want to use the hosted version
# os.environ["LANGCHAIN_API_KEY"] = "<YOUR-LANGCHAINPLUS-API-KEY>"  # Uncomment this line if you want to use the hosted version.

from langchain.client import LangChainPlusClient

client = LangChainPlusClient()

Listing Sessions

You can easily interact with Runs, Sessions (groups of traced runs), and Datasets with the client. For instance, to retrieve all of the top level runs in the default session, run:

session_name = "default"
runs = client.list_runs(session_name=session_name)

To list sessions:

sessions = client.list_sessions()

Datasets

The client is also useful for evaluating agents and LLMs on datasets. Check out the Datasets guide for more information.