Opus 5 System Prompt (github.com)

Anthropic has announced the release of Claude Opus 5, a highly advanced version of its AI assistant Claude, designed to tackle complex challenges. This model is now accessible via various interfaces, including web and mobile chat platforms, as well as through an API. Notably, Claude Opus 5 operates within a framework that includes safety measures, especially for sensitive topics like cybersecurity and biology. This following a prior suspension of access to Claude's earlier models due to U.S. export controls, which was lifted on June 30, 2026. The introduction of Claude Opus 5 is significant for the AI/ML community as it represents a substantial step in enhancing AI capabilities while prioritizing safety. The model is part of a broader lineup, including Claude Fable 5 and the newly introduced Mythos tier, which aims to further improve safety protocols in AI interactions. With advanced tools like Claude Code for coding tasks and Claude Cowork for knowledge work, the implications of this release extend to increased productivity and expanded usage in both professional and consumer applications. As developers continue to enhance AI capabilities along with safety measures, the community can expect ongoing advancements that balance power and responsibility in AI technologies.