Claude's System Prompts: A Peek Behind the Curtain

Claude: System Prompts

Anthropic has published the system prompts used by Claude on claude.ai and its mobile apps, revealing how the model is instructed to behave. The prompts provide up-to-date information like the current date and encourage specific behaviors, such as always formatting code in Markdown. These prompts are updated periodically to improve responses, and the page lists versions for each Claude model, from Opus 5 to Haiku 3, with dated entries. Notably, these system prompts do not apply to the Claude API.