STS2MCP is a free mod for Slay the Spire 2 that introduces AI agents to play the game autonomously. It offers a robust interface through a localhost REST API, which allows users to control the game state and actions. The mod supports both singleplayer and multiplayer modes, enabling various functionalities such as profile switching, character selection, and resuming saved co-op runs. As an experimental research tool, it aims to test AI capabilities in gaming while providing full menu and lobby control for an enhanced user experience.

The installation process is straightforward, requiring users to place specific files within the game’s mods directory and enable mod settings. Additionally, it includes features for tracking game progress and profile data through an HTTP API. While the mod is in beta phase for multiplayer functionality and may contain bugs, it serves as a pioneering project in AI gaming interaction, providing valuable insights into the strengths and weaknesses of current AI models.