Foundry VTT System Development

Build game systems for Foundry Virtual Tabletop (v14+). Systems define the core rules — Actor/Item types, dice mechanics, combat, character sheets — while modules extend them. This skill covers the full system lifecycle from manifest to publication. v13→v14 differences appear as "Changed in v14" notes; for the full list read foundry-vtt-module-dev/references/v14-migration.md.

This skill depends on foundry-vtt-module-dev for the shared references it points at (v14-migration.md, active-effects-v2.md, scene-levels.md, measured-templates.md) — install both.

Quick Start

System Structure