Claude Fable 5s Full System Prompt just got leaked online [o3l5hR7In1t]
Claude Fable 5 just came back, and someone has already leaked its entire system prompt online. And this isn't some basic prompt. It's 120,000 characters long, over 1,500 lines. That's the exact set of instructions Anthropic uses to control how their most powerful model thinks, plans, and gets work done. Think of it like getting the recipe from a Michelin-star restaurant. Same ingredients, same steps, way cheaper kitchen. The best part is you can take these exact instructions and inject them into cheaper open source models. Things like GLM 5.2 or Kimi K2.7. So they follow the same playbook Anthropic built for the world's best AI model. Same reasoning patterns, same tool use logic, same output quality. For anyone running local models or trying to cut API costs, this changes how much you can squeeze out of a smaller model. #Claudeai #fable5 #claudefable5 #claudeprompts #systemprompts