fine-tuning-with-trl

Fine-tune large language models with TRL using SFT, DPO, PPO, and GRPO.

Updated May 4, 2026
One-click install
npx skills add https://github.com/JamesFincher/gengar --skill fine-tuning-with-trl-jamesfincher
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: fine-tuning-with-trl
Source: https://github.com/JamesFincher/gengar/tree/main/skills/mlops/training/trl-fine-tuning
Command: npx skills add https://github.com/JamesFincher/gengar --skill fine-tuning-with-trl-jamesfincher

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes references (resource) components.

What problem does it solve?

This Skill provides practical guidance to fine-tune large language models with TRL for instruction alignment using SFT, DPO, PPO, and GRPO, including reward modeling and preference optimization workflows.

Core Features & Use Cases

  • SFT (Supervised Fine-Tuning): Train instruction-following behavior from prompt-completion pairs to get a strong starting policy.
  • Preference alignment (DPO): Align the model using chosen/rejected pairs without training a separate reward model.
  • RLHF alignment (PPO/GRPO + Reward Modeling): Optimize generations using either a learned reward model (PPO) or group-relative online rewards (GRPO), enabling reinforcement learning from human preferences or custom reward functions.
  • Use Case: Build an RLHF training pipeline that starts with SFT, trains a reward model from preference data, then runs PPO to improve responses using the reward signal.

Quick Start

Tell your AI to: "Create a DPO training run for a Qwen Instruct model using a chosen/rejected preference dataset, and include a safe set of key hyperparameters (beta, max lengths, and batch size)."

Frequently Asked Questions about fine-tuning-with-trl

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I fine-tune a large language model with TRL using DPO?

Fine-tune with TRL using DPO by aligning the model with chosen and rejected preference pairs. You can configure key hyperparameters like beta, max prompt length, and batch size to optimize preference alignment without training a separate reward model.

What is the best way to build a full RLHF pipeline with PPO and reward modeling?

Build a full RLHF pipeline by starting with SFT to establish a strong policy, training a reward model from preference data, and then running PPO to optimize model generations using the learned reward signal.

Can I use GRPO for memory-efficient online reinforcement learning with custom reward functions?

Yes, GRPO enables memory-efficient online reinforcement learning by optimizing generations using group-relative online rewards. This allows you to apply reinforcement learning from human preferences or custom reward functions.

Do I need to install transformers and peft to use TRL for instruction tuning?

Yes, using TRL for instruction tuning requires installing its ecosystem including transformers, datasets, peft, accelerate, and torch. You must select the correct dataset format and trainer to establish a strong starting policy.

What is the difference between SFT and DPO for aligning large language models?

SFT trains instruction-following behavior from prompt-completion pairs to get a starting policy, while DPO aligns the model using chosen and rejected pairs without training a separate reward model.

Why does TRL require specific max prompt and completion length configurations during preference optimization?

TRL requires configuring method-specific hyperparameters like max prompt and completion lengths to properly manage the generation counts and memory constraints during preference optimization and online reinforcement learning.