Agent Lightning⚡

The absolute trainer to light up AI agents.

Join our Discord community to connect with other users and contributors.

⚡ Core Features

• Turn your agent into an optimizable beast with ZERO CODE CHANGE (almost)! 💤
• Build with ANY agent framework (LangChain, OpenAI Agent SDK, AutoGen, CrewAI, Microsoft Agent Framework...); or even WITHOUT agent framework (Python OpenAI). You name it! 🤖
• Selectively optimize one or more agents in a multi-agent system. 🎯
• Embraces Algorithms like Reinforcement Learning, Automatic Prompt Optimization, Supervised Fine-tuning and more. 🤗

Read more on our documentation website.

⚡ Installation

pip install agentlightning

For the latest nightly build (cutting-edge features), you can install from Test PyPI:

pip install --upgrade --index-url https://test.pypi.org/simple/ --extra-index-url https://pypi.org/simple/ --pre agentlightning

Please refer to our installation guide for more details.

To start using Agent-lightning, check out our documentation and examples.

⚡ Articles

• 12/17/2025 Adopting the Trajectory Level Aggregation for Faster Training Agent-lightning blog.
• 11/4/2025 Tuning ANY AI agent with Tinker ✕ Agent-lightning Medium. See also Part 2.
• 10/22/2025 No More Retokenization Drift: Returning Token IDs via the OpenAI Compatible API Matters in Agent RL vLLM blog. See also Zhihu writeup.
• 8/11/2025 Training AI Agents to Write and Self-correct SQL with Reinforcement Learning Medium.
• 8/5/2025 Agent Lightning: Train ANY AI Agents with Reinforcement Learning arXiv paper.
• 7/26/2025 We discovered an approach to train any AI agent with RL, with (almost) zero code changes. Reddit.
• 6/6/2025 Agent Lightning - Microsoft Research Project page.

⚡ Community Projects

• DeepWerewolf — A case study of agent RL training for the Chinese Werewolf game built with AgentScope and Agent Lightning.
• AgentFlow — A modular multi-agent framework that combines planner, executor, verifier, and generator agents with the Flow-GRPO algorithm to tackle long-horizon, sparse-reward tasks.
• Youtu-Agent — Youtu-Agent lets you build and train your agent with ease. Built with a modified branch of Agent Lightning, Youtu-Agent has verified up to 128 GPUs RL training on maths/code and search capabilities with steady convergence. Also check the recipe and their blog [Stop Wrestling with Your Agent RL: How Youtu-Agent Achieved Stable, 128-GPU Scaling Without Breaking a Sweat](https://spotted-coconut-df8.notion.