Building Agents with LangChain and LangGraph: From GPT to Multi-Agent Systems

This workshop is organized by Visium for LauzHack LauzHack 2025 at EPFL. It gives an introduction to LLMs and demonstrates how to build sophisticated AI agents using LangChain.

Workshop Overview

The workshop explores the progression from basic language models to complex multi-agent systems through hands-on examples in financial analysis.

Introduction to LLMs and Agents

Learn the basics of building AI applications with LangChain, including:

• Setting up a basic chatbot
• Setting up a basic agentic system

Getting Started

Prerequisites

• Python 3.12 or higher
• OpenAI API key

Environment Setup

To set up your Python environment:

Using Conda/Mamba

# Use mamba instead of conda if preferred
conda create -n financial-advisor python=3.12
conda activate financial-advisor
pip install -e .

Using venv

python -m venv .venv

# On Linux/Mac:
source .venv/bin/activate
# On Windows:
.venv\Scripts\activate

pip install -e .

Using UV

uv sync

Configuration

You'll need to configure your OpenAI API key. Here are two ways to do it:

Set it as an environment variable:

export OPENAI_API_KEY='your-api-key-here'

Or store it in a .env file in your project root:

OPENAI_API_KEY='your-api-key-here'

Development Environment

This workshop uses Jupyter notebooks. You can run them using:

• VS Code with the Python extension installed
• Jupyter Lab through the web interface with jupyter lab

About

Visium

Visium is a Swiss-born AI & Data company helping businesses build their data-driven future through artificial intelligence and advanced data analytics. We help organizations leverage cutting-edge technology to solve complex business challenges.

LauzHack

LauzHack is an association created by EPFL aiming to bring together students and machine learning professionals. They are well known for their Hackathon which is considered one of the largest in Lausanne. For more information about LauzHack, visit https://lauzhack.com/.