Models

This page describes how to configure the chat model used by an agent.

Tool calling support

To enable tool-calling agents, the underlying LLM must support tool calling.

Compatible models can be found in the LangChain integrations directory.

Using initChatModel

The initChatModel utility simplifies model initialization with configurable parameters:

import { initChatModel } from "langchain/chat_models/universal";

const llm = await initChatModel(
  "anthropic:claude-3-7-sonnet-latest",
  {
    temperature: 0,
    maxTokens: 2048
  }
);

Refer to the API reference for advanced options.

Using provider-specific LLMs

If a model provider is not available via initChatModel, you can instantiate the provider's model class directly. The model must implement the BaseChatModel interface and support tool calling:

import { ChatAnthropic } from "@langchain/anthropic";
import { createReactAgent } from "@langchain/langgraph/prebuilt";

// highlight-next-line
const llm = new ChatAnthropic({
  modelName: "claude-3-7-sonnet-latest",
  temperature: 0,
  maxTokens: 2048
});

const agent = createReactAgent({
  // highlight-next-line
  llm,
  // other parameters
});

:::note[Illustrative example]

The example above uses ChatAnthropic, which is already supported by initChatModel. This pattern is shown to illustrate how to manually instantiate a model not available through initChatModel.

Additional resources

• Model integration directory
• Universal initialization with initChatModel