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GRPO Reinforcement Fine-Tuning

Guides an agent through GRPO reinforcement fine-tuning of language models with TRL and custom reward functions

Stars
14,195
Licence
MIT
Files
4 files

What it does

This skill gives an AI agent expert know-how for fine-tuning a language model with GRPO (Group Relative Policy Optimization), a reinforcement learning method. The model generates several answers per question, a scoring function rates them (for example for correct math answers or a required output format), and training nudges the model toward the higher-scoring answers. The skill supplies ready reward-function patterns, a dataset format, training settings, and a full example training script based on the TRL library.

Great for

  • ML engineers who want to train a small open model to follow a strict output format or solve verifiable tasks like math
  • Researchers experimenting with reward design for reasoning models
  • Developers who already have a clear, automatically checkable definition of a good answer

Skip it if

  • Simple instruction or style tuning with labelled examples, where supervised fine-tuning is the simpler choice (the skill itself says so)
  • Tasks with no objective reward signal, since the reward functions would be arbitrary and the training could drift badly
  • Running the example on a laptop or without a suitable GPU, as training a model requires significant compute and may incur cloud costs

Try asking

  • “Help me set up GRPO training to make a small Qwen model answer GSM8K math problems in a reasoning and answer XML format”
  • “Write a reward function that gives partial credit for correct XML tags in model outputs”
  • “Adapt the basic GRPO training template to my own question-and-answer dataset”
  • “Explain how group size and learning rate affect my GRPO training run”
Step-by-step guide: how to use GRPO Reinforcement Fine-TuningInstall, first run, examples, tips and FAQs

Install in 3 steps

  1. 1

    Download the skill

    The ZIP contains the 4 original files, the MIT licence and an attribution note.

    grpo-rl-training.zip
  2. 2

    Add it to your agent

    Claude Code (all projects)

    mkdir -p ~/.claude/skills && unzip grpo-rl-training.zip -d ~/.claude/skills/

    Claude Code / Agent SDK (this project only)

    mkdir -p .claude/skills && unzip grpo-rl-training.zip -d .claude/skills/

    Claude apps (web/desktop): Settings → Capabilities → Skills → Upload skill, and choose the ZIP.

  3. 3

    Ask for the task

    No special command needed — the agent reads the skill's description and loads it when your request matches. Try one of the prompts above.

Get better results

  • Start with a small model and a few training steps to verify the reward functions behave as expected before committing to a long run
  • Test each reward function in isolation on sample completions, as the skill recommends, before combining them
  • Review the training script and its dataset and model downloads before executing it, since it trains a model and fetches data from the internet

What's inside

  • examples/reward_functions_library.py
  • README.md
  • SKILL.md
  • templates/basic_grpo_training.py

Redistributed unmodified from Orchestra-Research/AI-Research-SKILLs under the MIT licence. The assessment was drafted with AI from the skill's files on 2026-10-29. Skills can instruct your agent to run code — read SKILL.md and any scripts before installing.