SDK Properties

Mod projects use the Lustral SDK:

<Project Sdk="Lustral.Sdk/0.1.0">
  <PropertyGroup>
    <LustralGame>Lethal Company</LustralGame>
    <ModId>you.betterhud</ModId>
    <Version>1.0.0</Version>
  </PropertyGroup>
</Project>

On every build, the SDK locates the game, selects the target framework (.NET 10 for IL2CPP games, .NET Standard 2.1 for Mono games), references Lustral.Api, HarmonyX and the game's assemblies without copying them, validates the project, generates the manifest and deploys the mod to <game>/Mods/<id>/.

Game

Property	Description
LustralGame	The game's folder name under a Steam library's steamapps\common (for example Lethal Company), or the full path to the game folder. All Steam libraries on the machine are searched.
LustralGameDir	The full path to the game folder. Takes precedence over LustralGame. Set it in Game.props.user next to the project to keep machine-specific paths out of source control.
LustralMonoGame, LustralIl2CppGame	Used instead of LustralGame for multi-backend mods: one game of each kind. The project is built once per backend (netstandard2.1 for Mono, net10.0 for IL2CPP), each against and into its game.
LustralMonoGameDir, LustralIl2CppGameDir	The full paths of those games, analogous to LustralGameDir.
LustralBackend	Set on the command line (-p:LustralBackend=Mono) to build only one backend of a multi-backend mod.

The SDK defines the following properties for use in the project: LustralBackend (Il2Cpp or Mono), LustralGameDirectory, LustralModsDirectory (the game's Mods folder), LustralInteropDirectory (IL2CPP) and LustralManagedDirectory (Mono), as well as the compilation symbol LUSTRAL_IL2CPP or LUSTRAL_MONO.

Mod Metadata

Property	Default	Description
ModId	Required	The mod ID: lowercase letters and digits, separated by single dots, dashes or underscores (you.betterhud). It names the mod's folder, settings file and log entries, and must not change.
ModName	Assembly name	The display name.
Version	1.0.0	The mod's semantic version.
Description		A one-sentence description of the mod.
Authors		The authors, separated by semicolons.
ModCredits		Acknowledgements, shown with the mod's details.
PackageLicenseExpression		An SPDX license expression, such as MIT.
PackageProjectUrl		The mod's website, written as its website link.
RepositoryUrl		The mod's source repository, written as its source link.
ModKind	mod	mod, or library for a library mod.
ModColor	Derived from the ID	The color of the mod's name in the console: a Unity color name (orange) or #rrggbb.
ModLoadOrder	0	Among mods that do not depend on each other, lower values load first.

Requirements

See Compatibility Requirements.

Property	Default	Description
ModLustralVersion	^<SDK version>	The supported Lustral versions, as a version range.
ModBackends	The game's backend	mono, il2cpp, or both: mono;il2cpp.
ModPlatforms	Any	windows, linux or macos, optionally followed by -x64, -x86 or -arm64; separated by semicolons.
ModUnityVersion	Any	A version range of supported Unity versions, such as >=2022.3.
ModProcesses	Any	Executable names, for games that ship more than one executable.

Distribution and Updates

See Publishing and Updates.

Property	Default	Description
ModUpdateSource		The update source: github:owner/repository, or the HTTPS address of a JSON feed.
ModUpdateAsset	The release's only .zip	For GitHub sources: the release file to download, with * wildcards.
ModPackage	false	true to also write <id>-<version>.zip to the output folder, containing the mod's folder, for attaching to a release.

Build and Launch

Property	Default	Description
LustralDeploy	true	false to build without deploying the mod to the game.
LustralLaunchSettings	true	false to prevent the SDK from writing Properties/launchSettings.json.
LustralSteamAppId	From the Steam library	The Steam app ID set by the launch profile, if the SDK cannot determine it.
LustralMonoDebuggerAddress	127.0.0.1:56000	The address of Mono's debugger agent, used by launch profiles for Mono games.

Items

<ItemGroup>
  <!-- Other mods -->
  <ModDependency Include="someone.uikit" Version="^1.2" />
  <ModDependency Include="someone.extras" Version="*" Optional="true" />
  <ModIncompatibility Include="someone.otherhud" Version="&lt;2.0" />

  <!-- Supported games -->
  <ModGame Include="BloonsTD6" Developer="Ninja Kiwi" Versions="56.*" />

  <!-- Additional links shown with the mod's details -->
  <ModLink Include="issues" Url="https://github.com/you/betterhud/issues" />

  <!-- Assemblies a library exposes to its dependents -->
  <ModExport Include="UiKit" />

  <!-- Files shipped with the mod -->
  <None Include="Assets\**" CopyToOutputDirectory="PreserveNewest" />
</ItemGroup>

Item	Metadata	Description
ModDependency	Version (required), Optional, Reference	A required mod, or with Optional="true", a mod used when present. If it is a library installed in the game, its exported assemblies are referenced (Reference="false" omits them). See Mod Dependencies.
ModIncompatibility	Version (default: all)	A mod this mod is incompatible with: if it is loaded, this mod is not.
ModGame	Developer, Versions	A supported game, by the name the game reports. Versions are separated by semicolons and support * wildcards.
ModLink	Url	A named HTTP(S) link.
ModExport		For libraries: an assembly name (without .dll) that dependents may use. Defaults to the library's own assembly.
Any item copied to the output		Deployed to the mod's folder at the same relative path and included in the release package. See Files and Data.

Validation

The build fails with a descriptive error when:

• ModId is missing or invalid, or ModKind is neither mod nor library.
• The game cannot be found or is not a Unity game.
• The project sets a TargetFramework other than the one required by the game's backend.
• The game uses IL2CPP and has no interop assemblies yet (launch the game once with Lustral installed).
• A version, version range, color, link, platform, backend or update source is malformed.