How to track token usage

This notebook goes over how to track your token usage for specific calls. This is currently only implemented for the OpenAI API.

Here's an example of tracking token usage for a single LLM call:

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

import { ChatOpenAI } from "@langchain/openai";

const chatModel = new ChatOpenAI({
  model: "gpt-4-turbo",
});

const res = await chatModel.invoke("Tell me a joke.");

console.log(res.response_metadata);

/*
  {
    tokenUsage: { completionTokens: 15, promptTokens: 12, totalTokens: 27 },
    finish_reason: 'stop'
  }
*/

API Reference:

• ChatOpenAI from @langchain/openai

If this model is passed to a chain or agent that calls it multiple times, it will log an output each time.