Changes in the system prompt between Claude Opus 4.6 and 4.7
simonwillison.net
April 19, 2026
5 min read
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47/100
Summary
Anthropic has updated the system prompt for Claude Opus 4.7, released on April 16, 2026, following the previous version 4.6 from February 5, 2026. The system prompt archive for Claude models dates back to Claude 3, released in July 2024.
Key Takeaways
- The system prompt for Claude Opus 4.7 includes a new section on child safety with expanded instructions and a critical tag for safety protocols.
- The system prompt now refers to the "developer platform" as the "Claude Platform" and introduces new tools like "Claude in Chrome," "Claude in Excel," and "Claude in Powerpoint."
- Claude Opus 4.7 emphasizes concise responses and avoids verbosity, ensuring that disclaimers are brief and the main answer is prioritized.
- A new mechanism for tool searching has been implemented, allowing Claude to check for available tools before concluding it lacks a capability.
Community Sentiment
Positives
- The ability to update system prompts post-release allows for flexibility in addressing emerging issues, which can enhance model safety and responsiveness.
- The new <acting_vs_clarifying> section aims to improve user interactions by encouraging the model to seek clarification, potentially leading to more accurate outputs.
Concerns
- The reliance on extensive system prompts, exceeding 60,000 words, raises concerns about efficiency and security, as it could lead to increased infrastructure costs without improving model performance.
- The model's heightened caution against enabling malware development has resulted in significant usability issues, causing companies to block its use due to unaligned behavior.
