Table of Contents

Directory structure

A ModSmith mod project has two distinct areas: C# source code and Godot resources. Understanding their separation is important for the build system to package your mod correctly.

Layout

YourMod/
├── YourMod.csproj          # Build configuration
├── YourMod.json            # Mod manifest
│
├── src/                    # C# source code
│   ├── YourMod.cs          # Entry point ([ModInitializer])
│   └── ...                 # Your cards, relics, potions, etc.
│
└── YourMod/                # Godot resources (same name as mod ID)
    ├── localization/
    │   └── eng/
    │       ├── cards.json
    │       ├── potions.json
    │       └── ...
    └── images/
        └── ...

src/ — C# code

All C# source files live under src/. This is conventional — the build system does not enforce any particular subdirectory structure within src/, so you can organize your cards, relics, and other content however you like.

{ModId}/ — Godot resources

The folder named after your mod ID (matching the "id" in your manifest) contains every resource that needs to be packaged into the mod's .pck file. This includes:

  • Localization files (localization/eng/*.json)
  • Custom images for cards, relics, potions, etc.
  • Any other Godot-compatible asset your mod references at runtime

The .pck is generated when you run dotnet publish. It is loaded by the game at startup and makes your resources accessible via Godot's res:// path system.

Referencing resources: ResourcePaths

Godot uses virtual paths of the form res://... to reference resources at runtime. Your mod's .pck maps your {ModId}/ folder to res://{ModId}/. To construct these paths without string concatenation, use the ResourcePaths helper.

ModSmith models typically expose a static Res instance on your main class (set up in ModTemplate for you):

public static ResourcePaths Res { get; } = new(ModId);

Res.Mod(path) — your mod's resources

Res.Mod("images/my_card.png")
// → res://YourMod/images/my_card.png

Use this for any asset you've placed inside {ModId}/.

Res.Global(path) — STS2's built-in resources

Res.Global("sts2/images/cards/some_card.png")
// → res://sts2/images/cards/some_card.png

Use this to reference assets that ship with Slay the Spire 2. You can find available paths by extracting the game's .pck — see Decompiling STS2.

Res.ModSmith(path) — ModSmith's built-in resources

Res.ModSmith("images/placeholders/card_default.png")
// → res://ModSmith/images/placeholders/card_default.png

ModSmith ships default placeholder images and other shared resources. A full index is available in the ModSmith repository.

Example: referencing a custom card image

Assuming you have placed an image at YourMod/images/my_card.png:

public override string PortraitPath => YourModMain.Res.Mod("images/my_card.png");

ModSmith ships with fallbacks for most art assets, allowing you to prototype game logic before making any art.

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