ART (Agent Reinforcement Trainer) is an open-source training framework for teaching agentic LLMs to improve performance and reliability through experience. ART provides a convenient wrapper around reinforcement learning techniques like GRPO (Group Relative Policy Optimization) to dramatically improve model performance while minimizing training costs.

Our docs will guide you through the process of training your own agents to operate more reliably and efficiently.

Why ART?

  • ART provides convenient wrappers for introducing RL training into existing applications. We abstract the training server into a modular service that your code doesn’t need to interface with.
  • Train from anywhere. Run the ART client on your laptop and let the ART server kick off an ephemeral GPU-enabled environment, or run on a local GPU.
  • Integrations with hosted platforms like W&B, Langfuse, and OpenPipe provide flexible observability and simplify debugging.
  • ART is customizable with intelligent defaults. You can configure training parameters and inference engine configurations to meet specific needs, or take advantage of the defaults, which have been optimized for training efficiency and stability.

Installation

ART agents can be trained from any client machine that runs python. To add to an existing project, run this command:

pip install openpipe-art

What is RL and when should I use it?

RL (reinforcement learning) is a set of training techniques that allow AI models to learn from their own experience.

Applying RL to an existing LLM can:

  • Improve overall agent reliablity
  • Correct specific mistakes detected in QA or production
  • Build confidence in agent performance before deploying to users

Examples:

  • Train a deep research agent to search and parse information from a knowledge store.
  • Resolve annoying bugs in model behavior by adding new training examples.
  • Build a lightning fast voice agent that always follows its script.

What do I need in order to use RL?

Getting started may be simpler than you expect.

Things you DO need:

  • ✅ A project that uses one or more LLMs.
  • ✅ Knowledge of the kinds of scenarios your LLM will have to handle.
  • ✅ That’s it!

Things you DON’T need:

  • ❌ A training dataset.
  • ❌ A complicated reward function.
  • ❌ A development machine with a GPU.
  • ❌ A PhD from MIT.
  • ❌ Existing RL expertise.

How to start using ART?

The ART client can be installed into projects designed to run on any machine that runs python. ART server can be run on any machine with a GPU, including your local laptop or within any cloud environment equipped with GPUs. To train an agent for free, try training a model to play 2048 on a free GPU in Google Colab.

Train an agent to play 2048

Or install ART into your existing project to start improving your agent’s performance!

Install ART in an existing project