Create a basic agent

In this guide we'll see how to create a simple basic agent that takes a prompt and executes operations using the BrianToolkit.

Create a new project

Create a new bun project using the following commands:

mkdir brian-basic-agent
cd brian-basic-agent
bun init

Select as your entrypoint of the project src/index.ts.

Install the dependencies

You need to install the following dependencies that we'll need later for the agent:

bun i @brian-ai/langchain dotenv @langchain/openai

Set the environment file

Create a .env file inside your newly created project and populate with the following variables:

BRIAN_API_KEY="" # your Brian API key
PRIVATE_KEY="" # the private key of your agent
OPENAI_API_KEY="" # your OpenAI api key. can be omitted here if set globally

Create the agent and run it!

Edit the src/index.ts file with the following content:

import "dotenv/config";
import { createBrianAgent } from "@brian-ai/langchain";
import { ChatOpenAI } from "@langchain/openai";
 
const BRIAN_API_KEY = process.env.BRIAN_API_KEY;
const PRIVATE_KEY = process.env.PRIVATE_KEY;
 
if (!BRIAN_API_KEY) {
  throw new Error("BRIAN_API_KEY is not set");
}
 
if (!PRIVATE_KEY) {
  throw new Error("PRIVATE_KEY is not set");
}
 
const main = async () => {
  const brianAgent = await createBrianAgent({
    apiKey: BRIAN_API_KEY,
    privateKeyOrAccount: PRIVATE_KEY as `0x${string}`,
    llm: new ChatOpenAI(),
  });
 
  const res = await brianAgent.invoke({
    input: "Swap 1 USDC for ETH on zkSync",
  });
  console.log(res.output);
};
 
main();

And then run the agent using the following command:

bun src/index.ts

You should see in your terminal the output of the agent.