Slay the Spire 2 Modding Tutorial¶
Version-aware documentation for building local C# and Godot content mods for Slay the Spire 2 Early Access.
Coverage¶
- current game layout, loader behavior, and version checks
net9.0projects referencing the assemblies shipped with the game- the external mod manifest, dependencies, staging, and installation
- decompiling
sts2.dlland inspectingSlayTheSpire2.pck [ModInitializer], semantic hooks, and Harmony patches- model discovery, pools, unlock visibility, and localization
- detailed custom card, potion, relic, act event, and GUI examples
- Godot
.pckresources and native UI integration - logs, save-state troubleshooting, packaging, and release verification
Verified Baseline¶
| Item | Value |
|---|---|
| STS2 | v0.107.1 |
| Commit | 59260271 |
| Release metadata date | 2026-06-18T15:43:56-07:00 |
| Target framework | net9.0 |
| Bundled .NET runtime | 9.0.7 |
| Main PCK format | Godot 4.5.1 |
Early Access updates can change signatures and loader contracts. Re-check release_info.json, sts2.runtimeconfig.json, and sts2.dll before maintaining a released mod.
Start Reading¶
Begin with Environment Setup, then follow the numbered chapters in the sidebar. The first nine chapters explain the runtime and packaging model. Chapters 10–14 apply it to a card, potion, relic, act event, and custom overlay. Chapter 15 develops persistent state, cloning, and deterministic randomness through a counter-based relic.
Use the Handbook Overview for the complete structure and source hierarchy.
Not Covered¶
This tutorial does not teach C#, Harmony, Godot, illustration, or game design from first principles. It documents how those tools connect to the current STS2 runtime.
Verification And Branches¶
Last API and resource inspection: 2026-11-04, stable v0.107.1 (59260271). This baseline describes the installed stable branch. The public beta is a separate compatibility target; do not assume its APIs or balance changes are present here.
The code examples are checked by compilation against the installed assemblies. Compilation and resource inspection do not replace the in-game validation matrices in each chapter.