Why OpenAI co-founder and the world's most famous AI researcher just joined Anthropic

Andrej Karpathy joined Anthropic on 19 May 2026. Most people read it as an OpenAI story — he co-founded the lab, left twice, and landed at the rival.That's not what this is. Eight weeks before he made the call, Karpathy built a 630-line Python script that ran 300 experiments on his own code in two days and found improvements he'd missed after months of hand-optimizing. He called it "the final boss battle." Anthropic then offered him the mandate to run that exact loop at the most consequential scale in the industry: using Claude to accelerate its own pre-training research.In this episode of In The Loop, I'm tracing what actually changed Karpathy's mind — from calling AI agents "terrible" in October 2025 to joining the lab pushing recursive self-improvement six months later. I cover autoresearch, what it found, and why Dario Amodei's quote about the AI-assistance multiplier is the most important thing said in frontier AI right now. ⏭️ Episode highlights(01:15) – Karpathy calls AI agents "terrible" in Oct 2025(02:30) – What changed: coding agents that basically work now(03:30) – 700 experiments, two days, 11% faster training(05:00) – What pre-training is and why it costs hundreds of millions(06:15) – AlphaEvolve and Codex: every lab running the same loop(07:10) – Dario Amodei: the multiplier going from 5% to 40%(08:20) – The METR study: experienced devs were 19% slower🔗 Links & resourcesAndrej Karpathy, X post announcing Anthropic hire, 19 May 2026 — https://x.com/karpathyGitHub: karpathy/autoresearch — https://github.com/karpathy/autoresearchAndrej Karpathy on Dwarkesh Patel podcast, October 2025 — https://dwarkesh.comDario Amodei on Dwarkesh Patel podcast, "We are near the end of the exponential", February 2026 — https://dwarkesh.com/p/dario-amodei-2Episode transcript with more resources on the Mindset AI blogIf you enjoyed this episode, rate, follow, and share. It helps others stay ahead of the latest AI trends.🤝 We're socialStay in the loop, even when you're not listening to this podcast.Jack Houghton LinkedIn - https://www.linkedin.com/in/jack-houghton1/TikTok - @jackschatsMindset AIMindset AI website - https://bit.ly/40lJr6BNewsletter - https://bit.ly/ITLnewsletterLinkedIn - https://www.linkedin.com/company/mindset-ai/YouTube - https://www.youtube.com/@GetMindsetAITikTok - @get.mindset.ai