Unlucky-Launcher/README.md

# Unlucky Launcher (ULL)

**English** · [简体中文](README.zh-CN.md)

> **Official project home**: https://github.com/AskaEth/Unlucky-Launcher ｜ downloads, issues and
> release notes all live there: <https://github.com/AskaEth/Unlucky-Launcher/releases>

Unlucky Launcher (ULL) is a free, open-source Minecraft: Java Edition launcher written in Rust
(Apache-2.0). It ships as one native binary per platform — no installer, no bundled runtime, no
WebView. The launcher embeds an AI agent client (chat / configuration / crash diagnosis) and can be
attached to other agent tooling as an MCP server.

## Compliance statement

- **Sign-in with your Microsoft account.** Authentication goes through Microsoft OAuth 2.0
  device code flow → Xbox Live → XSTS → `api.minecraftservices.com`, using the player's own
  Microsoft account and their own game entitlement.
- **Credentials stay on your machine.** Account tokens are stored locally only, are never sent to
  any server operated by this project, and the AI features cannot read them.
- **Online play requires a Microsoft account and a valid game entitlement.**
- ULL does not distribute, mirror, proxy or modify any Minecraft game files.
- Not affiliated with Mojang or Microsoft.

## Highlights

- **Single-file native binary**: the launcher itself needs no JVM, no WebView and no sidecar
  runtime. The JDK a game needs is downloaded and managed per instance, not as a launcher
  dependency.
- **Two UI stacks during the rewrite**: the released UI is Slint (Royalty-Free 2.0); the
  next-generation UI is iced 0.14 + Material 3 Expressive and is still being written (see Status).
- **CPU software-rendering fallback**: `--software-renderer` gives the full UI on machines with no
  usable GPU or with broken drivers.
- **AI agent + MCP**: chat, setting edits and crash diagnosis inside the launcher; `ull agent
  serve` exposes the same core as an MCP server (stdio or Streamable HTTP) to external agent tools.
- **Mod loaders**: Fabric, Quilt, NeoForge, Forge, with modpack and CurseForge / Modrinth clients in
  the core.
- **Java management**: a Temurin → Oracle → Microsoft → Zulu fallback chain, region-aware.
- **Engine**: multi-source download (health scoring, mirrors, chunked transfers, hash while
  downloading) and a YAML rule-based crash diagnosis engine.
- **License**: Apache-2.0 © AskaEth (YeiJ).

## Status

Two tracks. They are not the same product yet, so read the headings before downloading anything.

### Track A — released: v0.1.0, Slint UI (this is what you can download today)

- **GitHub Releases `v0.1.0`** (2026-11-01, flagged pre-release): single-file assets for Windows
  x64 (a bare `.exe`), Linux x64 and macOS (arm64 and x64) `.tar.gz`. Every release also carries
  `SHA256SUMS.txt` and the `LICENSE` / `NOTICE` / `README.md` texts as separate assets; on Windows
  those texts sit next to the `.exe` because a bare exe cannot hold them, while the unix archives
  already contain them.
- **UI**: Slint + Metro. This is the shipped GUI — the instance, download, account, Java, log and
  settings pages drive the real engine (the in-app AI chat panel is a scripted placeholder).
- **CLI `ull`** is built from the same tree at the same version and is fully usable — but the
  `v0.1.0` assets ship only the GUI binary. If you want the CLI, build it yourself:
  `cargo build --release --bin ull`. Commands: `instances`, `install`, `launch`, `accounts`,
  `sessions`, `logs`, `diag`, `config`, `java`, `agent`.
- Windows ARM64 and Linux ARM64 slots are wired into the release pipeline; the next tagged release
  builds them. The `v0.1.0` assets predate those two slots.

### Track B — in progress on `dev`: next-generation UI (iced + Material 3 Expressive)

**Nothing on this track is released, and no download contains it.** You can only see it by
building from source.

- **Locked direction**: the look is Material 3 Expressive and the framework is iced 0.14; the UI
  layer is written from scratch. Neither the style nor the framework will change again.
- **Done**: the token crate `crates/design` (no UI framework, no third-party crates — real HCT
  color, type scale, shape scale, spacing, elevation, motion, icon geometry, per-component
  metrics) and the skeleton crate `crates/app-iced` (opens a window, self-drawn title bar and
  window buttons, navigation rail, colors and type taken from tokens only, GPU→CPU backend probe
  with automatic fallback, and the screenshot/diff channel the visual reviews use).
- **Not done**: the component library (buttons, dialogs, lists, menus, search, and the rest of the
  M3 set), page migration, and the i18n pass. Every page in the iced binary is a placeholder.
- **Slint stays until the flip**: `crates/app` remains the reference implementation until the iced
  build passes equivalence acceptance; only then is `unlucky-launcher-iced` renamed to
  `unlucky-launcher` and the Slint crate retired.

Binaries in the workspace, so you can tell them apart:

| Binary | Crate | State |
|--------|-------|-------|
| `unlucky-launcher` | `crates/app` (Slint) | released in v0.1.0; still the usable GUI |
| `unlucky-launcher-iced` | `crates/app-iced` (iced 0.14) | under construction; skeleton only, not shipped |
| `ull` | `crates/cli` | built from the same tree at the same version; not shipped in the v0.1.0 assets |

## Module map

```
Unlucky-Launcher (cargo workspace)
├── crates/core       # domain library: zero UI dependencies, eight modules
├── crates/agent      # AI agent: ToolSpec registry + built-in client + MCP server (one core, two shapes)
├── crates/design     # design tokens: real HCT color / type / shape / spacing / elevation / motion / icons
│                     #   / component metrics — zero UI dependencies, no third-party crates
├── crates/app        # Slint UI (bin `unlucky-launcher`): the released GUI, kept until equivalence acceptance
├── crates/app-iced   # next-generation iced UI (bin `unlucky-launcher-iced`): under construction
├── crates/cli        # CLI (bin `ull`): headless, zero UI
└── packaging         # single-file artifact matrix and release scripts
```

The eight modules of `crates/core`:

| Module | Responsibility |
|--------|----------------|
| `setting` | three data-directory modes, schema-based config, atomic writes, migrations |
| `download` | multi-source health scoring, mirrors, chunked downloads, hash-while-downloading |
| `game` | version / instance repository, snapshots and inheritance resolution |
| `launch` | 10-stage launch pipeline, processes, JSONL event stream |
| `auth` | Microsoft sign-in (OAuth 2.0 device code → Xbox Live → XSTS → Minecraft Services) |
| `addon` | mod loader installation, modpacks, CurseForge / Modrinth |
| `diagnose` | five signal collectors, YAML rule engine, hs_err parsing |
| `platform` | OS abstraction: paths, processes, file locks, capability probing, runtime OS detection |

## Building

Prerequisites:

- Rust stable (`rust-toolchain.toml` selects the toolchain automatically; the gates also need the
  `rustfmt` and `clippy` components)
- Windows: MSVC toolchain (what CI uses) or MinGW-w64 (`x86_64-pc-windows-gnu`)
- Linux: `libxkbcommon-dev libfontconfig1-dev libgl1-mesa-dev libegl1-mesa-dev libwayland-dev
  libxcb1-dev` — needed by both UI stacks (Slint's winit + femtovg, iced's winit + wgpu/tiny-skia)

```bash
cargo fmt --all --check                                # formatting
cargo clippy --workspace --all-targets -- -D warnings  # lints (zero-warning gate)
cargo test --workspace                                 # tests
cargo build --release                                  # binaries land in target/release/
```

What the build produces:

- `unlucky-launcher` — the Slint UI (the released one)
- `unlucky-launcher-iced` — the iced UI skeleton. The name is temporary: it can only become
  `unlucky-launcher` at the flip, because two crates in one workspace cannot emit the same binary
  name into the same target directory.
- `ull` — the CLI

Rendering switches:

- `unlucky-launcher --software-renderer` (equivalent to `SLINT_BACKEND=winit-software`) forces the
  CPU path on the Slint build
- `unlucky-launcher-iced --software-renderer` forces tiny-skia (`ICED_BACKEND=tiny-skia`);
  `--screenshot <png>` writes one frame and exits, which is the acceptance channel
- Both stacks fall back to the CPU path when no usable adapter is there: the Slint build through its
  own renderer fallback chain, the iced build through its explicit probe

Dependency license check (optional locally, required in CI):
`cargo deny check licenses bans sources`.

## CI gates

Every push to `main` and every pull request runs fmt / clippy (warnings are errors) / the full test
suite, and the Linux headless render smoke is a hard gate on the same footing: a red result blocks
the merge. The macOS runtime probe is not there yet — it only runs on a manual `workflow_dispatch`
and its result is recorded, not enforced (`continue-on-error`), until the slot passes a first run on
a real runner.

| Workflow | Content |
|----------|---------|
| `.github/workflows/ci.yml` | fmt + clippy + test + release build (Windows / Linux matrix); Linux runtime smoke (Xvfb: renders one real frame, then asserts the PNG is not blank); macOS runtime probe (manual dispatch only) |
| `.github/workflows/guards.yml` | zero-UI guard for `crates/core` (manifest plus `cargo tree`), 400-lines-per-file guard, cargo-deny license and source guard |
| `.github/workflows/release.yml` | tag `v*` → per-slot builds → single-file artifacts + `SHA256SUMS.txt` → GitHub Release |

## Platform baseline

Minimum baseline: **Windows 10**; Windows 8.1 / 8 / 7 are not supported.

- Windows 10/11 builds use the **standard toolchain** (MSVC / GNU) — no custom target specs, no
  `-Zbuild-std`, no import-table allowlists
- macOS 12+ (Apple Silicon and Intel) and Linux x64 / arm64 are supported build slots; on Linux,
  X11 is the preferred path today and Wayland is the long-term direction. macOS builds are unsigned,
  so the first launch needs the Gatekeeper quarantine attribute cleared
  (`xattr -d com.apple.quarantine`)
- Android Termux is experimental and not promised: CLI only, GUI unverified
- Platform independence is expressed through **separate test matrices**, not separate artifact
  pipelines; capability differences use feature gates with runtime probing
- **Renderer fallback on both UI stacks**: the Slint build drops to software rendering, the iced
  build drops from wgpu to tiny-skia, so a machine without a usable GPU still gets the full UI

## License and acknowledgements

- **This project**: Apache License 2.0, see [LICENSE](LICENSE); third-party notices in
  [NOTICE](NOTICE).
- **Slint** (<https://slint.dev>), Royalty-Free 2.0: obligation for the Slint build that v0.1.0
  ships — an `AboutSlint` widget on the about page (still outstanding) and, until it lands, the
  NOTICE file, this section and a "Made with Slint" note on the release page. The obligation is
  kept for as long as a Slint-linked binary ships.
- **iced** (<https://github.com/iced-rs/iced>), MIT: the framework of the next-generation UI,
  together with `winit` and, through it, `wgpu` / `tiny-skia` (Apache-2.0 / MIT).
- **Google Material Color Utilities** (Apache-2.0): the color tokens in `crates/design` are a Rust
  port of its HCT / ColorSpec2021 algorithms; details and the exact ported functions are listed in
  [NOTICE](NOTICE).
- **Other major dependencies**: `rmcp` and `axum` (Apache-2.0 / MIT) for the MCP server, `tokio`
  (MIT), `reqwest` with rustls (MIT / Apache-2.0), `serde` / `serde_json` (MIT / Apache-2.0),
  `zip` / `flate2` / `tar` (MIT / Apache-2.0). The allow-list cargo-deny enforces is in `deny.toml`;
  GPL-family dependencies may not enter the main line.

Thanks to [HMCL](https://github.com/HMCL-dev/HMCL) and
[PCL2](https://github.com/Meloong-Git/PCL) (both GPL-3.0) — those two old-timers have been riding
along with the overwhelming majority of Minecraft players for years now. This launcher learned an
enormous amount from them about how a launcher should feel and how it should work, and it exists
very much in their debt.