ModSmith

ModSmith is a modding framework for Slay the Spire 2 that makes it easy to add new content to the game in C#. It provides base classes, a registration system, and tooling so you can focus on adding cool nonsense into the game.

Get started

• Playing mods — Install ModSmith once to enable any mod that depends on it.
• Building mods — New to modding? Start with the guided setup. Experienced C# developer? Jump straight to the manual.

Supported content

ModSmith supports the following content types out of the box:

• 🃏 Cards — New attacks, skills, and powers for any card pool.
• 🧪 Potions — Single-use items with arbitrary effects.
• 🏺 Relics — Persistent passive items that hook into combat and run events.
• ⚡ Powers — Stackable status effects applied to players or enemies.
• 🗺️ Events — Multi-page branching narrative encounters on the map.
• 🪙 Ancients — Special ancient encounter events with relic rewards.

All content hooks into the same event system the base game uses, giving you full access to everything that happens during a run.