GitHub Post Shares Claude Fable 5.1 Prompt

Brian Roemmele posted about the Anthropic Claude Fable 5.1 system prompt. He stated that the text runs 270,000 characters and that users pay for it with each prompt. The text appears in a repository maintained by elder-plinius that collects prompts from multiple AI systems. Anthropic maintains a page that references the Claude Fable 5.1 system prompt and its updates on claude.ai and the mobile apps.