Claude's fable 5.1 system prompt just leaked publicly A hacker known as Pliny the Liberator leaked Claude's Fable 5.1 system prompt, all 270,000 characters, now public on GitHub. Not the model itself, the instructions that tell it how to behave and respond. Copying these into a cheaper AI won't give you Fable 5.1's intelligence, that's built into the model, not the prompt. What it does show: how a major AI company structures instructions for its own model. Useful if you use AI for coding, since most people give AI barely any guidance then wonder why results are inconsistent. Share this with a developer on your team. Save it for your next prompt rewrite. #ClaudeAI #AIPrompts #PromptEngineering #AITools #technews