foundry-vtt-system-dev

Build custom Foundry Virtual Tabletop game systems with system.json and template.json configuration.

17|2|Updated Feb 25, 2026

Search Tags:#game design #rpg #foundry vtt #system development #foundry vtt module

Ready to run

npx skills add https://github.com/fcsouza/agent-skills --skill foundry-vtt-system-dev

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: foundry-vtt-system-dev
Source: https://github.com/fcsouza/agent-skills/tree/main/skills/foundry-vtt-system-dev
Command: npx skills add https://github.com/fcsouza/agent-skills --skill foundry-vtt-system-dev

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill requires foundry-vtt-module-dev, and includes scripts (resource) and references (resource) components.

What problem does it solve?

This Skill provides comprehensive support for building, extending, and maintaining Foundry Virtual Tabletop (FVTT) systems, enabling you to create sophisticated game mechanics, character sheets, and more without needing to write extensive code.

Core Features & Use Cases

System Development: Facilitates the creation of custom game systems with support for system.json, template.json, and more.
Customization: Allows for full customization of Actor/Item types, dice mechanics, combat systems, and character sheets.
Integration: Seamlessly integrates with existing FVTT modules and APIs for a seamless user experience.
Use Case: Imagine you want to create a custom combat system for your FVTT campaign. This Skill provides the tools and guidance to develop a comprehensive system from scratch.

Quick Start

Run the following command to create a new FVTT system with the default structure: foundry-vtt-system-dev create-system --name "my-system".

Frequently Asked Questions about foundry-vtt-system-dev

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

How do I build a custom Foundry VTT system from scratch?▼

Building a custom Foundry VTT system involves creating system.json and template.json configuration files, defining Actor and Item types, and customizing combat mechanics. You can scaffold the default structure using the `foundry-vtt-system-dev create-system --name "my-system"` command.

What do I need to create custom RPG combat mechanics in Foundry VTT?▼

Creating custom RPG combat mechanics in Foundry VTT requires Foundry Virtual Tabletop v13+ and applicable module dependencies such as foundry-vtt-module-dev. This Skill supplies the tools and templates needed to define and implement your custom combat systems.

Can I customize character sheets and Actor types in Foundry VTT?▼

Yes, you can fully customize Actor and Item types, character sheets, and dice mechanics for your Foundry VTT system. This Skill provides templates and tools that allow you to define and extend these components without writing extensive code.

Does this Foundry VTT system development approach work with existing modules?▼

Yes, this approach to Foundry VTT system development seamlessly integrates with existing FVTT modules and APIs. It requires the foundry-vtt-module-dev dependency to ensure proper integration and a cohesive user experience.

What is the best way to configure system.json and template.json for a Foundry VTT game?▼

The best way to configure system.json and template.json for a Foundry VTT game is to use a dedicated system development Skill that provides structured templates. This ensures your custom game system is properly defined and maintained without extensive coding.