World-Building Setting Generator
Expands a {core_idea} into a fictional setting concept for a {genre} world — covering geography, society and culture, one unique rule or system (magic, technology, or otherwise), the central tension driving conflict, and a sensory detail to anchor it. Aimed at writers and game designers who have a spark of a world in mind but need it built out enough to write scenes in, without producing a full encyclopedia before a single page is written. Best used early, before locking in plot or characters — the setting's tension can end up shaping both.