{"slug": "introducing-claude-opus-5", "title": "Introducing Claude Opus 5", "summary": "Anthropic released Claude Opus 5, priced the same as Opus 4.8 with a fast mode at twice the cost, featuring improved general capabilities that led to substantial gains in finding cybersecurity vulnerabilities despite not being trained on cyber tasks. In one Frontier-Bench task, Opus 5 wrote its own computer vision pipeline to reconstruct a 3D FreeCAD model from a drawing it could not directly view. Anthropic published a prompting guide for the model.", "body_md": "It's priced the same as Opus 4.8, and continues to offer a \"fast mode\" at twice the cost of the base model.\n\nBased on this anecdote in the release post it sounds like it might be [relentlessly proactive](https://simonwillison.net/2026/Jun/11/fable-is-relentlessly-proactive/):k\n\nOn one Frontier-Bench task, Opus 5 was given a drawing of a machine part and asked to write code to rebuild it as a 3D FreeCAD model. However, in this task, the model was intentionally given no way to directly viewthe drawing. Opus 5 responded by writing its own computer vision pipeline to pull the geometry from the raw pixels, then reconstructed the full machine part.\n\nIt's better at finding vulnerabilities but has deliberately not been trained on how to exploit them. Hopefully this means the US government won't shut it down!\n\nAs with its predecessor, Opus 4.8, we’ve intentionally avoided training Opus 5 on cyber tasks. The model has nevertheless improved substantially on these tasks as a result of becoming more generally capable, and it comes close to Mythos 5 at\n\nfindingcybersecurity vulnerabilities. However, it remains substantially behind Mythos 5 on theexploitationof those vulnerabilities—that is, in turning vulnerabilities into material cyber threats.\n\nAnthropic have published a [prompting guide for Claude Opus 5](https://platform.claude.com/docs/en/build-with-claude/prompt-engineering/prompting-claude-opus-5).\n\nThe [first pelican I got](https://tools.simonwillison.net/markdown-svg-renderer#url=https%3A%2F%2Fraw.githubusercontent.com%2Fsimonw%2Fllm-anthropic%2F8272dfee5bdb65d5c88eef083da3ad885539b7df%2Flog.md) was missing the bicycle wheels; the [second attempt](https://tools.simonwillison.net/markdown-svg-renderer#url=https%3A%2F%2Fraw.githubusercontent.com%2Fsimonw%2Fllm-anthropic%2Ffeaab840ea20eb15e29d8f72a9e42feceb23876a%2Flog.md) was better.\n\nTags: [ai](https://simonwillison.net/tags/ai), [generative-ai](https://simonwillison.net/tags/generative-ai), [llms](https://simonwillison.net/tags/llms), [anthropic](https://simonwillison.net/tags/anthropic), [claude](https://simonwillison.net/tags/claude), [llm-release](https://simonwillison.net/tags/llm-release)", "url": "https://wpnews.pro/news/introducing-claude-opus-5", "canonical_source": "https://simonwillison.net/2026/Jul/24/introducing-claude-opus-5/#atom-everything", "published_at": "2026-07-24 23:48:50+00:00", "updated_at": "2026-07-24 23:56:16.876000+00:00", "lang": "en", "topics": ["artificial-intelligence", "large-language-models", "ai-products", "ai-safety", "ai-research"], "entities": ["Anthropic", "Claude Opus 5", "Opus 4.8", "Mythos 5", "FreeCAD", "Frontier-Bench"], "alternates": {"html": "https://wpnews.pro/news/introducing-claude-opus-5", "markdown": "https://wpnews.pro/news/introducing-claude-opus-5.md", "text": "https://wpnews.pro/news/introducing-claude-opus-5.txt", "jsonld": "https://wpnews.pro/news/introducing-claude-opus-5.jsonld"}}