Changes in the system prompt between Claude Opus 4.6 and 4.7

2026-04-20

Anthropic is the only major AI lab to publish the system prompts for its user-facing chat systems. The company just released Opus 4.7, which features an updated system prompt. This author used Claude Code to take the Markdown version of its system prompts, break them into separate documents, and then construct a Git history of those files with fake commit dates. The result is in the post.