verl-rl-training

verl-rl-training is a skill for Claude Code, Codex from ihatesea69/HieuNghi-AI-Skills. It costs 51 tokens per session (2,768 once invoked), scanned A, a copy of verl-rl-training, MIT.

A guide to verl, a library for training large language models with reinforcement learning. Reinforcement learning improves a model by rewarding preferred behavior, and language-model post-training adapts a model after its initial training.

In plain words
What is it for?
Use it to plan or implement RLHF, GRPO, PPO, and other language-model training workflows, including multi-turn tool use and vision-language models.
Why use it?
It helps teams choose training methods and computing software for reinforcement-learning work, including methods such as PPO and GRPO. It also explains when simpler supervised or preference-training tools may be a better fit.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to plan or implement RLHF, GRPO, PPO, and other language-model training workflows, including multi-turn tool use and vision-language models.

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Install with agentmods
npx agentmods add skills/ihatesea69/hieunghi-ai-skills/verl
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add ihatesea69/HieuNghi-AI-Skills --skill verl
Clone the repo
git clone --depth 1 https://github.com/ihatesea69/HieuNghi-AI-Skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for verl-rl-training

README.md
[![agentmods](https://agentmods.dev/badge/skills/ihatesea69/hieunghi-ai-skills/verl/github.svg)](https://agentmods.dev/skills/ihatesea69/hieunghi-ai-skills/verl)
Your own site
<a href="https://agentmods.dev/skills/ihatesea69/hieunghi-ai-skills/verl"><img src="https://agentmods.dev/badge/skills/ihatesea69/hieunghi-ai-skills/verl/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for verl-rl-training

Your own site · 80×15
<a href="https://agentmods.dev/skills/ihatesea69/hieunghi-ai-skills/verl"><img src="https://agentmods.dev/badge/skills/ihatesea69/hieunghi-ai-skills/verl.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 51 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,768 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 100% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00051 $0.02768
Opus 5 $0.00026 $0.01384
Sonnet 5 $0.00010 $0.00554
Haiku 4.5 $0.00005 $0.00277

Measured 12d ago against content hash 1167e2b2994c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

verl-rl-training scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 12d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

100% identical to verl-rl-training — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

airesearch_skills/06-post-training/verl/SKILL.md · 392 lines

How it starts

The opening of the file, as written. The whole thing — 392 lines — stays where its author put it; the contents beside it link to each section on GitHub.

verl: Volcano Engine Reinforcement Learning for LLMs

verl is a flexible, efficient, and production-ready RL training library for large language models from ByteDance's Seed team. It implements the HybridFlow framework (EuroSys 2025) and powers models like Doubao-1.5-pro achieving O1-level performance on math benchmarks.

When to Use verl

Choose verl when you need:

  • Production-ready RL training at scale (tested up to 671B parameters)
  • Flexibility to swap backends (FSDP ↔ Megatron-LM ↔ vLLM ↔ SGLang)
  • Support for multiple RL algorithms (PPO, GRPO, RLOO, REINFORCE++, DAPO)
  • Multi-turn rollout with tool calling for agentic workflows
  • Vision-language model RL training

Consider alternatives when:

  • You need Megatron-native training → use slime or miles
  • You want PyTorch-native abstractions with Monarch → use torchforge
  • You only need simple SFT/DPO → use TRL or Axolotl

Key Features

  • Training backends: FSDP, FSDP2, Megatron-LM
  • Rollout engines: vLLM, SGLang, HuggingFace Transformers
  • Algorithms: PPO, GRPO, DAPO, RLOO, ReMax, REINFORCE++, SPIN, SPPO
  • Models: Qwen-3, Llama-3.1, DeepSeek, Gemma-2 (0.5B to 671B)
  • Advanced: LoRA RL, sequence parallelism, expert parallelism, multi-turn tools

Installation

# Option 1: pip install
pip install verl[vllm]  # or verl[sglang] for SGLang backend

# Option 2: Docker (recommended for production)
docker pull verlai/verl:vllm011.latest

# Option 3: From source
git clone https://github.com/volcengine/verl.git
cd verl && pip install -e .[vllm,math]

Quick Start: GRPO Training

python3 -m verl.trainer.main_ppo \
    algorithm.adv_estimator=grpo \
    data.train_files=~/data/gsm8k/train.parquet \
    actor_rollout_ref.model.path=Qwen/Qwen2.5-7B \
    actor_rollout_ref.rollout.n=8 \
    actor_rollout_ref.actor.use_kl_loss=True \
    trainer.n_gpus_per_node=8

Core Architecture

verl uses a HybridFlow programming model separating control flow from computation:

Read the full file on GitHub · 392 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 12d ago First seen · 392 lines · 51 tokens per session scan A 1167e2b2994c

Subscribe to this mod's changes

verl-rl-training is a skill published in the GitHub repository ihatesea69/HieuNghi-AI-Skills (3 stars, last pushed 6mo ago), licensed MIT. It adds 51 tokens to every session and 2,768 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to verl-rl-training, differing in 0 lines, and is treated as a copy.

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