  The role of a Dungeon Master, or DM, in the game Dungeons & Dragons is to
perform multiple tasks simultaneously. The DM must digest information about the
game setting and monsters, synthesize scenes to present to other players, and
respond to the players' interactions with the scene. Doing all of these tasks
while maintaining consistency within the narrative and story world is no small
feat of human cognition, making the task tiring and unapproachable to new
players. Large language models (LLMs) like GPT-3 and ChatGPT have shown
remarkable abilities to generate coherent natural language text. In this paper,
we conduct a formative evaluation with DMs to establish the use cases of LLMs
in D&D and tabletop gaming generally. We introduce CALYPSO, a system of
LLM-powered interfaces that support DMs with information and inspiration
specific to their own scenario. CALYPSO distills game context into bite-sized
prose and helps brainstorm ideas without distracting the DM from the game. When
given access to CALYPSO, DMs reported that it generated high-fidelity text
suitable for direct presentation to players, and low-fidelity ideas that the DM
could develop further while maintaining their creative agency. We see CALYPSO
as exemplifying a paradigm of AI-augmented tools that provide synchronous
creative assistance within established game worlds, and tabletop gaming more
broadly.
