If you're using Claude anywhere – apps, API, Claude Code – you should upgrade to Sonnet 4.5. It's a drop-in replacement for Sonnet 4, same price, significantly better across the board.
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Sonnet 4.5 Achieves 82% on SWE-bench with Test-Time Compute
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Sonnet 4.5 hits 82% on SWE-bench with test-time compute. We're adding another dot to what's been a pretty clean exponential toward saturating SWE-bench as a benchmark. At this rate we'll need new evals soon, but it's still a useful signal that the capability curve is holding.
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Claude Sonnet 4.5: Advanced Coding Model with Superior Design
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Introducing Claude Sonnet 4.5. The best coding model in the world combined with the best character of any model I've seen.
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Anthropic to release Claude Sonnet 4.5 soon
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BREAKING : Anthropic is about to release Claude Sonnet 4.5 soon! SOTA on SWE bench
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AI Impact on Programming Careers Reassurance Note
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More on my blog, including this hopefully reassuring note for anyone afraid of the impact this will have on their career as a programmer https://
simonwillison.net/2025/Sep/29/ar
min-ronacher-90/
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AI-Generated Code in Infrastructure: Armin’s Credible 90% Achievement
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Most of the "90% of code written by AI" claims come from vendors selling AI tools and lack credibility as a result Armin (creator of Flask, Jinja, Click) is different – when he says 90% of a new infrastructure project he's building was AI generated it's worth paying attention
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Hyperparameter Changes for Muon Optimization and Optimizer Comparison
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What hyperparameters changed when optimizing for muon? @clashluke has tried several new optimizers on our code and not reliably beaten Adamw.
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Vibecoding risks: maintaining code control through methodical steps
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The moment i start #vibecoding, i loose control of my code base. You got to be very careful. It might look very tempting initially to reduce your workload, but actually it makes your work difficult if you don't go step by step.
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Quarantined LLM Systems Modeled as Tool Calls
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Yeah, the quarantined LLM stuff can absolutely be modeled as tool calls instead
