Writing a novel is hard. Keeping it consistent past 50,000 words is harder. Mythpen is a local-first desktop studio that keeps your characters, world rules, chapters, timeline and foreshadowing in one story bible — then grounds its AI co-writer in it. Guided and collab workflows, TXT/EPUB import, a payoff kanban for serials, consistency checks, EPUB/HTML/Markdown export. Bring your own OpenAI-compatible or Claude key. Free, open source, macOS/Windows/Linux.
