Claude Opus 5 System Prompt Leaked on GitHub, Revealing 34,000-Token Instruction Set
A developer has leaked the complete system prompt for Anthropic's Claude Opus 5 on GitHub, exposing an extensive 34,000-token instruction set. The leaked prompt details the model's internal guidelines for tool usage, legal compliance, and cross-session memory management. This leak provides AI researchers and prompt engineers with rare, direct insight into how Anthropic structures complex instructions for its flagship model to handle safety, privacy, and memory. It highlights the intricate engineering required to prevent AI models from developing unhealthy user dependencies or storing sensitive personal data. The prompt contains a 230-line memory_filesystem section that restricts Claude to storing only explicitly stated user facts under a [stated] tag, while banning inferences, health diagnoses, and family names. Additionally, it prohibits the model from using specific words like "genuinely" and "honestly" to maintain a professional tone.
## BACKGROUND
System prompts are foundational instructions set by developers to guide a Large Language Model's (LLM) behavior, tone, and constraints before a user session begins. Tokens are the basic units of text (characters or subwords) that LLMs process, with larger token counts indicating more complex and detailed instruction sets.