> ## Documentation Index
> Fetch the complete documentation index at: https://miles.radixark.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Developer Guide

> Contribution conventions, internal architecture, dependency versions, and debugging.

You're here because you want to change Miles, not just use it. This section is the
short tour for new contributors.

<CardGroup cols={2}>
  <Card title="Contributing" icon="file-pen" href="/docs/developer/contributor-guide">
    Repo layout, what enforces code style, what lives in .claude, and how to drive CI from a PR.
  </Card>

  <Card title="Architecture Overview" icon="diagram-project" href="/docs/developer/architecture">
    The 30-minute tour of how Miles is organized internally.
  </Card>

  <Card title="Versions and Images" icon="layer-group" href="/docs/developer/versions">
    How the miles, SGLang and Megatron-LM trees fit together, and how to bump one.
  </Card>

  <Card title="Debugging" icon="bug" href="/docs/developer/debug">
    Isolating rollout from training, the debug and CI assertion flags, aligning precision.
  </Card>

  <Card title="Training Backends" icon="server" href="/docs/user-guide/training-backend">
    Megatron-LM and FSDP: what each backend owns and where its code lives.
  </Card>
</CardGroup>

## TL;DR for first-time contributors

1. Pick something small from `good first issue` on [GitHub](https://github.com/radixark/miles/issues).
2. Run the [Reproducibility recipe](https://github.com/radixark/miles/tree/main/examples/experimental/reproducibility) so you can be sure
   "I changed X and it broke" actually means that.
3. Use `--debug-train-only` or `--debug-rollout-only` to scope your changes, and
   `--list-only` to confirm your test is actually registered in CI.
4. Open a PR. We'll review within \~48h.