Heart of Dorkness

Abstract

"Hermetic Foundry" is a free, open-source character-creation and saga-management application for Ars Magica, a complex tabletop roleplaying game whose rules and source texts were released under an open license in 2024. The project began as a modest AI-assisted user interface prototype and became an experiment: could an experienced programmer build a serious XML-aware desktop application by "vibe coding" almost everything through ChatGPT and Codex? The surprising result was not chaotic XML. The schema set validated cleanly, used stable identifiers and cross-references, and developed into a package architecture with fixtures and regression validation. The most persistent failures appeared instead in the generated user interface and in the AI tools’ own interfaces. This paper presents Hermetic Foundry as a case study in LLM-assisted XML software development, arguing that a two-LLM workflow – one refining prose, one implementing code – plus expert review can produce surprisingly robust, schema-disciplined software.