
Agent Lightning
A training framework that uses reinforcement learning to improve AI agents running with their real tools.
- Stars
- 18.9k
- Forks
- 1.7k
- Licence
- MIT
- Language
- Python
- Last update
- 4 days ago
- Type
- Framework
What it is
Agent Lightning is a Python framework for training AI agents with reinforcement learning. Instead of rewriting an agent to fit a training system, the README says agents keep their existing tools, context, and control flow while a proxy records their model interactions as training data. It is aimed at researchers and engineers who want to improve how an agent behaves on tasks such as coding or search.
- Train a math reasoning agent with the Calc-X or GSM8K examples
- Run a coding agent trained against repository tests using the Coding Agent example
- Run agents as Kubernetes Jobs with the built-in Kubernetes support
- Study training pipelines through the published examples and technical report
Great for
- Researchers experimenting with reinforcement learning on LLM agents
- Engineers who already have an agent and want to improve it with training data
- Teams with GPU access who can run the documented verl and vLLM stack
- Anyone following the coding-agent examples on SWE-bench Verified
Not ideal for
- People who only want to use an existing AI assistant, since this is a training tool, not an end-user app
- Users without GPU resources, because the examples and installation assume CUDA-capable hardware
- Beginners new to reinforcement learning or LLM training, who will likely find the setup and concepts heavy
How to get it
- 1
Clone and build from source
You'll need: Python · uv · CUDA-capable GPU (the example uses CUDA 13.0)
Enter the repository directory
cd <this-repo>Install Python dependencies with uv
uv syncSet up the verl GPU stack
bash scripts/setup_verl.sh 0.8.0 cu130 - 2
Run it
- Follow the Installation Guide in the documentation
- Work through the Quick Start page for a local first run
- Read the Basics page to learn about components, rollouts, and trajectories
- Try a small example such as Calc-X, which the README says needs only one GPU
- 3
Get the most out of it
- Read the Trainer Configuration page to understand verl integration and trace aggregation
- Use the Controller Configuration page to choose between local and Kubernetes runners
- Review the Asynchronous Training page for collocated async collection and pause/drain
- Look at the Agent Lightning Skill referenced in the README, which helps a coding agent improve another agent
Downloads
Strengths
- The README describes a small core of about 3,500 lines, with three named components: Trainer, API Gateway, and Rollout Controller
- Works with real agent harnesses without requiring code changes, according to the README
- Ships multiple worked examples, including coding, search, and sandbox agents
Trade-offs
- Requires significant GPU setup; the documented install example targets a CUDA 13.0 machine
- Several reported results are from the project's own evaluations and have not been independently verified here
- Version 1.0 was refactored, so older v0.x material may not apply
How it compares
| Project | Stars | Type | Level | Updated | Best for |
|---|---|---|---|---|---|
| agent-lightning (this) | 18.9k | Framework | advanced | 4 days ago | Researchers experimenting with reinforcement learning on LLM agents |
| learn-harness-engineering | 22.9k | Learning resource | beginner | 14 days ago | Developers new to building or controlling AI coding agents |
| Octop | 11.5k | App | intermediate | 4 days ago | Households or small teams that want a shared, self-hosted assistant |
| wandb | 11.3k | Library | beginner | 4 days ago | Machine learning engineers who want to compare training runs over time |
| MetaGPT | 71.1k | Framework | intermediate | 10 months ago | Developers experimenting with multi-agent LLM workflows |
| eliza | 19.8k | Framework | advanced | 4 days ago | Developers who want to build AI agents or plugins in TypeScript |
Stats synced from GitHub. The assessment above was drafted with AI from the project's README on 2026-10-29 and may miss recent changes — check the README before relying on a command. MIT licence: free to use, modify and distribute, including commercially, as long as you keep the copyright notice.