Structured chat

info

If you are using a functions-capable model like ChatOpenAI, we currently recommend that you use the OpenAI Functions agent for more complex tool calling.

The structured chat agent is capable of using multi-input tools.

Older agents are configured to specify an action input as a single string, but this agent can use the provided tools' schema to populate the action input.

Setup

Install the OpenAI integration package, retrieve your key, and store it as an environment variable named OPENAI_API_KEY:

tip

See this section for general instructions on installing integration packages.

npm

npm install @langchain/openai

Yarn

yarn add @langchain/openai

pnpm

pnpm add @langchain/openai

This demo also uses Tavily, but you can also swap in another built in tool. You'll need to sign up for an API key and set it as TAVILY_API_KEY.

Initialize Tools

We will first create a tool:

import { TavilySearchResults } from "@langchain/community/tools/tavily_search";

// Define the tools the agent will have access to.
const tools = [new TavilySearchResults({ maxResults: 1 })];

Create Agent

import { AgentExecutor, createOpenAIToolsAgent } from "langchain/agents";
import { pull } from "langchain/hub";
import { ChatOpenAI } from "@langchain/openai";
import type { ChatPromptTemplate } from "@langchain/core/prompts";

// Get the prompt to use - you can modify this!
// If you want to see the prompt in full, you can at:
// https://smith.langchain.com/hub/hwchase17/structured-chat-agent
const prompt = await pull<ChatPromptTemplate>(
  "hwchase17/structured-chat-agent"
);

const llm = new ChatOpenAI({
  model: "gpt-3.5-turbo-1106",
  temperature: 0,
});

const agent = await createStructuredChatAgent({
  llm,
  tools,
  prompt,
});

Run Agent

Now, let's run our agent!

tip

LangSmith trace

const agentExecutor = new AgentExecutor({
  agent,
  tools,
});

const result = await agentExecutor.invoke({
  input: "what is LangChain?",
});

console.log(result);

/*
  {
    input: 'what is LangChain?',
    output: 'LangChain is a project on GitHub that focuses on building applications with LLMs (Large Language Models) through composability. It offers resources, documentation, and encourages contributions to the project. LangChain can be used for tasks such as retrieval augmented generation, analyzing structured data, and creating chatbots.'
  }
*/

Using with chat history

For more details, see this section of the agent quickstart.

import { AIMessage, HumanMessage } from "@langchain/core/messages";

const result2 = await agentExecutor.invoke({
  input: "what's my name?",
  chat_history: [
    new HumanMessage("hi! my name is cob"),
    new AIMessage("Hello Cob! How can I assist you today?"),
  ],
});

console.log(result2);

/*
  {
    input: "what's my name?",
    chat_history: [
      HumanMessage {
        content: 'hi! my name is cob',
        additional_kwargs: {}
      },
      AIMessage {
        content: 'Hello Cob! How can I assist you today?',
        additional_kwargs: {}
      }
    ],
    output: 'Your name is Cob.'
  }
*/