## Overview When I started working on **Baldur's Gate 3 Mod Configuration Menu (MCM)**, my goal was to make modding easier for both modders and players. However, designing a framework that integrates seamlessly with any scripting mod in Baldur’s Gate 3 turned out to be an exercise in much more than just coding. Early on, I realized that modders had their own ways of implementing settings: - Some relied on manual JSON config edits 📝 - Others wanted to build custom UI elements 📐 - Many avoided configuration options due to the complexity of implementation 🙅 The challenge was to create a system that was both flexible and intuitive, without forcing a one-size-fits-all approach. Players had to dig through JSON files to configure mods. I wanted to change that. Creating MCM required: - Understanding the needs of developers and players; - Designing an intuitive system that balanced flexibility and ease of use by offering clear and comprehensive APIs for modders, and user-friendly UI for players; - Making careful decisions to ensure long-term extensibility and maintainability. That meant engaging directly with developers and players to refine my approach based on practical use cases. As Don Norman puts it: > "Design is really an act of communication, which means having a deep understanding of the person with whom the designer is communicating." No matter how many mods I had created before MCM, or how much I knew about scripting, good design requires direct engagement, iteration, and feedback. I spent countless hours with the modding community, gathering feedback, iterating on designs, and testing prototypes. I also had to consider how MCM would fit into the existing modding ecosystem, ensuring it was easy to adopt and integrate with other mods. I developed MCM to streamline how mods expose their settings — from simple checkboxes and sliders to advanced constructs like keybindings and lists — all validated against a shared JSON schema. This significantly reduces the development time and technical knowledge needed for authors to offer customizable experiences. ## Engineering highlights - **Declarative configuration system** – Designed a JSON-based "blueprint" schema that defines how each mod's settings are structured, validated, and rendered in-game. - **Simple Lua API** – Implemented a robust global MCM API enabling runtime access to settings (MCM.Get, MCM.Set), event subscriptions, and UI extensions. - **Automatic validation and persistence** – implemented two-stage validation (blueprint and runtime) ensuring safe loading, saving, and migration of user settings without data loss or version conflicts. - **Extensible UI layer** – Built a unified IMGUI-based menu integrated into Baldur's Gate 3's existing UI, supporting localization handles, real-time updates, and conditional visibility logic. - **Keybinding & UI notification systems** – Introduced high-level APIs for keybinding management and customizable notifications, enabling complex mod behaviors without reimplementing input or UI logic. - **Tested and resilient** – Wrote 40+ automated tests verifying schema integrity and mod isolation, so errors in one integration don't affect others. ## Community impact Since its **May 2024 release**, MCM has become the highest-ranking mod of its first 365 days on Nexus Mods and grown into a widely adopted framework: - **Now adopted by 150+ Baldur's Gate 3 mods, including top scripting mods on Nexus, and 680k+ players**, becoming the standard configuration framework for the modding ecosystem. - **Simplified mod support**: MCM has lowered the barrier to entry for novice modders and streamlined the workflow for experienced developers, allowing them to focus on their mods' unique features. - [**Thorough documentation**](https://wiki.bg3.community/en/Tutorials/Mod-Frameworks/mod-configuration-menu): this includes a quick-start guide, example blueprints, and detailed API references to facilitate easy integration. - **Recognized and funded through Nexus Mods' '*Top Authors*' program** for outstanding developer tooling. ## Tech stack - **Lua & BG3 Script Extender** — core runtime integration and API design - **JSON & JSON Schema** — blueprint structure and IDE-assisted validation - **IMGUI/Dear ImGui** — in-game graphical interface