Simon Willison analyst · 3d ago · 2/5
Changes in the system prompt between Claude Opus 4.6 and 4.7 ↗
Anthropic released Claude Opus 4.7 on April 16, 2026, with notable system prompt updates documented by Simon Willison. Key changes include expanded child safety instructions, new integrations with Claude in Chrome, Excel, and PowerPoint, and modifications to encourage more concise responses and tool-assisted problem-solving. The analysis reveals Anthropic's approach to model behavior refinement through system prompt evolution, with removals of outdated guardrails reflecting improved model capabilities.
Anthropic are the only major AI lab to publish the system prompts for their user-facing chat systems.
Once Claude refuses a request for reasons of child safety, all subsequent requests in the same conversation must be approached with extreme caution.