Claude's new system prompt really doesn't want to reproduce song lyrics
Anthropic published updated Claude consumer system prompts, including changes steering the model away from reproducing song lyrics, likely over copyright concerns.
Anthropic publishes system prompts for Claude.ai and Claude mobile apps, including historic revisions, and has reorganized them into an index with per-model pages such as the Haiku 4.5 page showing the original October 15, 2025 prompt and an updated January 18, 2026 version. The latest consumer prompt strongly discourages reproducing song lyrics, a behavioral constraint likely tied to copyright considerations. Prompts for Claude Cowork and Claude Code are not included in the published set.
- Anthropic maintains public system prompts with full change history for consumer apps
- New prompt heavily restricts song lyric reproduction, likely for copyright reasons
- Prompts reorganized into per-model pages, e.g. Haiku 4.5 (Oct 2025 and Jan 2026 versions)
- Claude Code and Claude Cowork system prompts are not published
From the original article
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.
simonwillison.net
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