retrain

retrain is a TOML-first RLVR (Reinforcement Learning with Verifiable Rewards) trainer for LLMs, built to make experiments easier to run, compare, and repeat.

If you are new, start with install -> explore commands -> run a tiny config.

Install

Requires Python 3.11+.

# CLI + docs exploration
uv tool install retrain

# Local GPU training (adds torch)
uv tool install "retrain[local]"

# Remote Tinker backend
uv tool install "retrain[tinker]"

If you are developing this repo directly:

pip install -e ".[dev]"

Explore the CLI

Use these first to understand what exists before you train:

retrain --help
retrain man
retrain man --topic quickstart
retrain man --list-topics
retrain backends
retrain doctor

Useful inspection commands while iterating:

retrain explain retrain.toml   # dry-run: what this config would do
retrain status logs            # summarize runs/campaigns under logs/
retrain plugins                # list built-ins + discovered plugins
retrain init-plugin --kind transform --name my_transform --with-test
retrain man --json --topic quickstart
retrain man --path             # editable bundled manual source

Tiny TOML Demo

Create mini.toml:

max_tokens = 1024 below is an intentional smoke-test profile. The standard default for full runs is max_tokens = 10240.

[model]
model = "Qwen/Qwen3-4B-Instruct-2507"

[algorithm]
advantage_mode = "grpo"
transform_mode = "none"

[training]
max_steps = 20
batch_size = 2
group_size = 8
max_tokens = 1024
lr = 4e-5

[backend]
backend = "local"
adapter_path = "adapters/mini"

[logging]
log_dir = "logs/mini"

Run it:

retrain mini.toml

Override fields from CLI without editing TOML:

retrain mini.toml --seed 42 --max-steps 40 --wandb-project my-project

Quick Start from Template

retrain init --template quickstart
retrain retrain.toml

Other templates:

retrain init --list
retrain init --template experiment
retrain init --template campaign
retrain init --interactive

retrain Workflow

The normal retrain loop is:

1. Define TOML config (retrain.toml or campaign.toml)
2. Dry-run with retrain explain ...
3. Train with retrain ...
4. Inspect with retrain status logs

Use retrain man --topic capacity only when you are sizing longer runs.

Why retrain

• Experiment-first workflow: config -> explain -> run -> compare
• Composable advantage pipeline: GRPO/MaxRL + GTPO/HICRA/SEPA
• Pluggable backends and inference engines
• Pluggable rewards (match, math, judge, custom)
• Campaign sweeps from one TOML
• LoRA-Squeeze rank analysis/compression
• Checkpoint resume and run status tooling

Common Config Patterns

Use verifiers environments from TOML:

[environment]
provider = "verifiers"
id = "primeintellect/gsm8k"
args = { split = "train" }
auto_install = true
max_turns = 8

Use custom advantage + transform plugins from TOML:

[algorithm]
advantage_mode = "my_advantages.hipa_like_advantages"
transform_mode = "my_transforms.make_transform_spec"

Use a full algorithm plugin (overrides composable advantage+transform path):

[algorithm]
algorithm_mode = "my_algorithms.my_algorithm"

Documentation

Full docs: retrain.readthedocs.io

• Getting Started
• Configuration Reference
• Advantage Functions
• SEPA Scheduling
• Campaigns
• Capacity Planning
• LoRA-Squeeze
• Reward Functions
• Inference Engines

Contributor note: run retrain man --check in CI to detect stale auto-generated manual blocks, run retrain man --sync locally to refresh them, and run uv run mkdocs build --strict before publishing docs changes.