Claude's new system prompt doesn't want to reproduce song lyrics
Anthropic has updated its system prompts for Claude to explicitly forbid the reproduction of copyrighted song lyrics, poems, and book passages. This change follows ongoing legal challenges from music publishers regarding the use of copyrighted material in AI training data.
Why it matters
It highlights the growing legal pressure on AI companies to implement stricter copyright guardrails within their model architectures.
Anthropic publish the system prompts for their Claude consumer applications ( Claude.ai and the Claude mobile apps—sadly not for Claude Cowork or Claude Code). I love that they do this, and that they share not just the current prompts but historic changes to their prompts as well.
They used to keep all of the prompts on a single page, but when I checked today I noticed they had re-arranged those prompts into an index page and then a page per model—here’s the page for Haiku 4.5 for example, which has the original prompt from October 15th 2025 and an updated prompt from January 18th 2026.
A neat thing about Anthropic’s platform.claude.com/docs site is that it’s designed to be usable by LLMs. You can add .md to any page to get back the content as Markdown—here’s the system prompt index page and the Markdown prompts for Fable 5.1 .
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