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Zeitgeist — a spike by Chris Gathercole
  1. Creators/
  2. Simon Willison — Creator of Datasette; co-creator of Django/

Introducing Claude Opus 5

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  • Anthropic released Claude Opus 5, pitched as coming “close to the frontier intelligence of Claude Fable 5 at half the price,” and currently topping the Artificial Analysis leaderboard.
  • Willison highlights a proactive-problem-solving example: given no direct way to view a machine-part drawing, the model independently built a computer-vision pipeline to extract geometry from raw pixels rather than giving up.
  • On security, Opus 5 got better at identifying vulnerabilities without explicit cyber training, but Anthropic deliberately kept it lagging at actually exploiting them (behind Mythos) — a design choice Willison approves of.
  • Practical takeaway: solid capability gain at competitive pricing with a considered safety posture; worth testing, though Willison hadn’t personally run it yet at time of writing.