Official agent skill

Cosmos3 Post Training

by NVIDIA in NVIDIA/cosmos-framework

Guide users through Cosmos3 supervised fine-tuning (SFT) post-training: preparing the example dataset and Wan2.2 VAE, converting the base checkpoint to DCP, launching distributed training (paired…

OfficialCustom licenceAuto-check passedAI & LLM Engineering

Install Cosmos3 Post Training

skills CLI
$ npx skills add NVIDIA/cosmos-framework --skill cosmos3-post-training -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install NVIDIA/cosmos-framework cosmos3-post-training --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/NVIDIA/cosmos-framework.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.agents/skills/cosmos3-post-training .claude/skills/cosmos3-post-training && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
cosmos3-post-training
GitHub stars
558
Token cost
~2.7k tokens
SKILL.md length
964 words
Files
1
Skills in repo
5
Repo updated
First seen
Licence
Custom licence

At a glance

Guide users through Cosmos3 supervised fine-tuning (SFT) post-training: preparing the example dataset and Wan2.2 VAE, converting the base checkpoint to DCP, launching distributed training (paired…

  • Works in 8 steps: Setup — install the training extras: uv… → Step 1 - Prepare data and config — for… → Step 2 — Prepare checkpoint — set… → …
  • The user asks how to post-train Cosmos3
  • SKILL.md covers When to use this skill, Path convention, Where to find answers and Workflow at a glance, plus 2 more sections
  • Calls uv, python and uvx; needs WANDB_API_KEY

What it does

Cosmos3 Post Training is an agent skill from NVIDIA/cosmos-framework, published by the product's own GitHub organization. Guide users through Cosmos3 supervised fine-tuning (SFT) post-training: preparing the example dataset and Wan2.2 VAE, converting the base checkpoint to DCP, launching distributed training (paired launch shell recommended, raw torchrun as an alternative), running T2V/I2V/V2V inference with the trained DCP checkpoint, and optionally exporting it to Hugging Face safetensors. Use when the user asks how to post-train Cosmos3, fine-tune on a custom video dataset, export a trained checkpoint, or invoke one of the recipe…

Its SKILL.md is about 2.7k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in AI & LLM Engineering, covering Fine-tuning, Model hubs and datasets and Deep learning. It works with Hugging Face and CUDA. The repository describes itself as: Our inference and training framework to run on the Cosmos Models.

When your agent uses it

  • The user asks how to post-train Cosmos3
  • Fine-tune on a custom video dataset
  • Export a trained checkpoint
  • Invoke one of the recipe launch shells (launchsftvisionnano.sh

Example prompts

  • “/cosmos3-post-training”

Requirements

  • Python 3
  • A credential in WANDB_API_KEY

Workflow steps

8 steps, taken from the first numbered list in SKILL.md.

  1. Setup — install the training extras: uv sync --all-extras --group=cu130-train (or cu128-train on older drivers), then source…
  2. Step 1 - Prepare data and config — for the recipe you're running, download the HF dataset to examples/data// and the Wan2.2 VAE to…
  3. Step 2 — Prepare checkpoint — set BASE_CHECKPOINT_NAME (Cosmos3-Nano or Cosmos3-Super, matching the recipe) and run python -m…
  4. Step 3 — Run training (Option A, recommended) — from the repo root, bash examples/launch_sft_.sh (e.g. launch_sft_vision_nano.sh). The…
  5. Step 3 — Run training (Option B, raw torchrun) — export the env vars yourself, then IMAGINAIRE_OUTPUT_ROOT=outputs/train PYTHONPATH=…
  6. Outputs — $RUN_DIR = $IMAGINAIRE_OUTPUT_ROOT///. DCP checkpoints land under $RUN_DIR/checkpoints/iter_/; the latest iter name is in…
  7. Inference — point cosmos_framework.scripts.inference at $RUN_DIR/checkpoints/iter_ together with --config-file $RUN_DIR/config.yaml (see…
  8. Export (optional) — python -m cosmos_framework.scripts.export_model --checkpoint-path $RUN_DIR/checkpoints/$(cat…

What it can do on your machine

Read from SKILL.md and the folder at commit 8aca062. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    Shell commands in SKILL.md call:

    • uv
    • python
    • uvx
    • bash

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    No URLs in SKILL.md. Its commands use uv and uvx, which can reach the network depending on how they are called.

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names these keys or tokens, usually read from environment variables:

    • WANDB_API_KEY

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Cosmos3 Post Training loads about 2.7k tokens when it runs. Until then it costs about 218 tokens; SKILL.md has 964 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~218
When it runs · the whole SKILL.md, loaded when a task matches
~2.7k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

Its licence (Custom licence) doesn't allow us to republish the file, so here is its outline and opening line. It has 964 words (~2,742 tokens).

“All paths below are relative to the cosmos3 package root (../../../ from this skill file). All uv run / python / torchrun / bash commands should also be run from there.”

— opening of SKILL.md by NVIDIA, Custom licence
name
cosmos3-post-training

Read the full SKILL.md on GitHub

Files

Just SKILL.md in .agents/skills/cosmos3-post-training of NVIDIA/cosmos-framework.

Open the folder on GitHubat commit 8aca062

Compare with similar skills

Cosmos3 Post Training next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Cosmos3 Post Training compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Cosmos3 Post Training this skillNVIDIA/cosmos-framework558—~2.7kAutomated safety check: PassCustom licence
Megakernel OptimizationRightNow-AI/AutoMegaKernel148—~1.8kAutomated safety check: PassMIT
Kermt FinetuneNVIDIA/skills3.5k1 repos~4.1kAutomated safety check: PassApache-2.0
Discover MLrand/cc-polymath1811 repos~574Automated safety check: PassMIT
Mamba State-Space ModelsOrchestra-Research/AI-Research-SKILLs13k3 repos~1.8kAutomated safety check: PassMIT
Hugging Face LLM Trainerhuggingface/skills11k3 repos~7.2kAutomated safety check: PassApache-2.0

Similar skills

  • Megakernel Optimization

    RightNow-AI/AutoMegaKernel

    A skill your agent uses when optimizing or generating a CUDA megakernel for a HuggingFace Llama-family model with AutoMegaKernel (AMK), drives the correctness-gated propose - eval - keep/revert loop…

    148 GitHub stars~1.8k tokensUpdated 21 days ago
    AI & LLM EngineeringAuto-check passed
  • Kermt Finetune

    NVIDIA/skills

    Official

    Finetune a pretrained KERMT encoder on a labeled CSV. An agent skill from NVIDIA/skills.

    3.5k GitHub starsUsed in 1 repo~4.1k tokens
    AI & LLM EngineeringAuto-check passed
  • Discover ML

    rand/cc-polymath

    Automatically discover machine learning and AI skills when working with machine learning, PyTorch, training, inference, RAG, embeddings, fine-tuning, LLM, DSPy, HuggingFace, or diffusion models.

    181 GitHub starsUsed in 1 repo~574 tokens
    AI & LLM EngineeringAuto-check passed
  • Mamba State-Space Models

    Orchestra-Research/AI-Research-SKILLs

    Guide to using Mamba selective state-space models for linear-time sequence modeling, from the Mamba block and pretrained checkpoints to Mamba-2 and speed comparisons.

    13k GitHub starsUsed in 3 repos~1.8k tokens
    AI & LLM EngineeringAuto-check passed
  • Hugging Face LLM Trainer

    huggingface/skills

    Official

    Trains or fine-tunes language and vision models with TRL or Unsloth on Hugging Face Jobs cloud GPUs, then converts the results to GGUF.

    11k GitHub starsUsed in 3 repos~7.2k tokens
    AI & LLM EngineeringAuto-check passed
  • Dataset Transformation

    awslabs/agent-plugins

    Official

    Generates code that transforms datasets between ML schemas for model training or evaluation.

    915 GitHub starsUsed in 2 repos~3.5k tokens
    AI & LLM EngineeringAuto-check passed

More from NVIDIA/cosmos-framework

  • Cosmos3 Codebase Nav

    NVIDIA/cosmos-framework

    Official

    Navigate the Cosmos3 package codebase to find where parameters, configs, defaults, scripts, and documentation live.

    558 GitHub stars~2.8k tokensUpdated yesterday
    Auto-check passed
  • Cosmos3 Env Troubleshoot

    NVIDIA/cosmos-framework

    Official

    Diagnose and fix Cosmos3 environment, installation, and runtime errors.

    558 GitHub stars~1.3k tokensUpdated yesterday
    Auto-check: notes
  • Cosmos3 Inference

    NVIDIA/cosmos-framework

    Official

    Guide users through running Cosmos3 inference — offline batch generation, online serving with Ray and Gradio, parallelism options, input formats, sampling parameters, and prompt upsampling.

    558 GitHub stars~1.2k tokensUpdated yesterday
    Auto-check passed
  • Cosmos3 Setup

    NVIDIA/cosmos-framework

    Official

    Guide users through Cosmos3 installation, environment setup, checkpoint downloading, and verification.

    558 GitHub stars~1.1k tokensUpdated yesterday
    Auto-check: notes

Questions about Cosmos3 Post Training

What does Cosmos3 Post Training do?

Guide users through Cosmos3 supervised fine-tuning (SFT) post-training: preparing the example dataset and Wan2.2 VAE, converting the base checkpoint to DCP, launching distributed training (paired…. Cosmos3 Post Training is an agent skill from NVIDIA/cosmos-framework, published by the product's own GitHub organization.2 VAE, converting the base checkpoint to DCP, launching distributed training (paired launch shell recommended, raw torchrun as an alternative), running T2V/I2V/V2V inference with the trained DCP checkpoint, and optionally exporting it to Hugging Face safetensors.

When should I use Cosmos3 Post Training?

Cosmos3 Post Training fits situations like: the user asks how to post-train Cosmos3; fine-tune on a custom video dataset; export a trained checkpoint; invoke one of the recipe launch shells (launchsftvisionnano.sh.

How do I install Cosmos3 Post Training in Claude Code?

Run `npx skills add NVIDIA/cosmos-framework --skill cosmos3-post-training -a claude-code`. Or copy the skill folder (.agents/skills/cosmos3-post-training in NVIDIA/cosmos-framework) into .claude/skills/cosmos3-post-training in your project. Claude Code loads it when a task matches its description.

How do I install Cosmos3 Post Training in Codex?

Run `npx skills add NVIDIA/cosmos-framework --skill cosmos3-post-training -a codex`. Or copy the skill folder (.agents/skills/cosmos3-post-training in NVIDIA/cosmos-framework) into .agents/skills/cosmos3-post-training in your project. Codex loads it when a task matches its description.

Can I use Cosmos3 Post Training in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add NVIDIA/cosmos-framework --skill cosmos3-post-training -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/cosmos3-post-training, .gemini/skills/cosmos3-post-training, .github/skills/cosmos3-post-training and .opencode/skills/cosmos3-post-training in your project.

What does Cosmos3 Post Training need to run?

Going by SKILL.md and its folder, Cosmos3 Post Training needs the command-line tools its instructions call (uv, python, uvx and bash) and credentials named WANDB_API_KEY. Our summary lists: Python 3; A credential in WANDB_API_KEY.

Does Cosmos3 Post Training access the network?

SKILL.md contains no URLs. Its commands use uv and uvx, which can reach the network depending on how they are called. This is read from the text; nothing was executed.

Is Cosmos3 Post Training safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Cosmos3 Post Training use?

Cosmos3 Post Training has a licence file (the repository's licence) that doesn't match a standard licence. Read it on GitHub before reusing the skill.

How many tokens does Cosmos3 Post Training use?

About 2.7k tokens (SKILL.md is roughly 11k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Cosmos3 Post Training?

Skills that share tags, products or a category with Cosmos3 Post Training: Megakernel Optimization (RightNow-AI/AutoMegaKernel, 148 stars), Kermt Finetune (NVIDIA/skills, 3.5k stars), Discover ML (rand/cc-polymath, 181 stars) and Mamba State-Space Models (Orchestra-Research/AI-Research-SKILLs, 13k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Cosmos3 Post Training?

NVIDIA (a GitHub organization, an official publisher) maintains it in NVIDIA/cosmos-framework, which has 558 GitHub stars. The repository holds 5 skills in this directory. The repository was last updated on October 8, 2026.

Source: NVIDIA/cosmos-framework on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.