OpenStory
An LLM-powered multi-agent framework for simulating interactive, evolving story worlds, where characters perceive, plan and act on their own while a player can also give direct instructions and steer the plot.
OpenStory drives its simulations with an agent-kernel architecture that supports dynamically adding and removing agents at runtime, plus a plugin system covering an agent's perception, planning, execution and reflection lifecycle, configured through YAML files for systems, environments, actions and agents. Its example stories include a full-scale recreation of a classical Chinese novel's garden setting with a matching visualized map interface, a science-fiction theme-park story where characters perceive, plan, move, talk and accumulate memory, and a mode that turns one natural-language premise into generated characters, locations, paths and rules for a new interactive simulation.
A free mode lets a user simply observe agents acting autonomously, while a plot mode lets them give characters direct instructions and watch the story branch in response, with the ability to roll back to earlier story points and take a different path. It is written in Python and ships a standalone launcher client for one-click play.