Claude 4’s system prompt is very similar to the 3.7 prompt we analyzed last month. They’re nearly identical, but the changes scattered throughout reveal much about how Anthropic is using system prompts to define their applications (specifically their UX) and how the prompts fit into their development cycle. Let’s step through the notable changes. Old Hotfixes Are Gone, New Hotfixes Begin We theorized that many random instructions, targeting common LLM “gotchas”, were hot-fixes: short instruction...