BelmontUI

BelmontUI is a library for Castlevania: Belmont’s Curse mods running on BepInEx 6 (IL2CPP). It adds a MODS SETTINGS tab to the game’s pause menu, and to the Settings screen on the title screen. Each mod that registers settings gets a row on that tab with its title, a one-line summary and a Settings button. The button opens the mod’s own sub-menu, built from the game’s own toggles, sliders, list steppers and buttons.

A mod declares its settings once, in Load(), with a few lines of C#:

BelmontUi.Settings.Register(Plugin.Guid, "My Mod", menu =>
{
    menu.Toggle(Plugin.Enabled, "Enabled");
    menu.Slider(Plugin.Opacity, "Opacity", 0.2f, 1f, 0.05f, "{0:0%}");
    menu.ResetButton();
}, summary: "What my mod does, in one line.");

The dependency is optional. A mod that uses BelmontUI still loads and works without it, minus its entry on the tab.

Documentation map

Page	For	What it covers
Getting started	players and mod authors	Installing, requirements, the soft-dependency pattern with a full example
API reference	mod authors	Every public member, what each row kind looks like, RegisterFromConfig rules
Recipes	mod authors	Copy-paste examples for common menus
How it works	the curious, maintainers	Tab placement, widget cloning, game updates, saving
Troubleshooting	players and mod authors	Log lines, the “no tab” checklist, compatibility
Changelog	everyone	Versions 0.1.0 to the current one

For AI coding agents

The repository’s AGENTS.md lets Claude, Codex, Cursor and similar agents add BelmontUI support to a mod without reading the source. A machine-readable index of this site is at llms.txt.

License

MIT. See LICENSE.