Andrej Karpathy joins Anthropic's pre-training team to use Claude to speed up pre-training research
On May 19, 2026 Andrej Karpathy (OpenAI co-founder, former Tesla AI director, creator of "vibe coding") announced on X that he had joined Anthropic. He works in pre-training under team lead Nick Joseph and is starting a team that uses Claude to accelerate pre-training research, pausing (not closing) his education startup Eureka Labs. The post drew about 28 million views.
Key facts
- X post, May 19, 2026 15:05 UTC: 'Personal update: I've joined Anthropic. I think the next few years at the frontier of LLMs will be especially formative. I am very excited to join the team here and get back to R&D. I remain deeply passionate about education and plan to resume my work on it in time.'
- Reach (fxtwitter, Oct 4, 2026): ~28.0M views, ~149K likes, ~10.9K reposts
- Role (Anthropic spokesperson to TechCrunch): pre-training under Nick Joseph; he will start a team focused on using Claude to accelerate pre-training research
- Eureka Labs, the AI-education company he founded in 2024 after leaving OpenAI a second time, is paused
- Came nine days before Anthropic's Series H at a $965B valuation (May 28)
What happened
Karpathy, one of the best-known AI researchers and educators, joined Anthropic rather than returning to OpenAI. Anthropic said his team will use Claude itself to accelerate pre-training research, an early instance of a lab staffing a team around models improving the next model.
Why it matters
It was the most visible talent move of spring 2026 and a signal of Anthropic's pull with researchers. Since then Karpathy's public posts (e.g. testing Opus 5 on a 1M-token Three.js build) have come from inside Anthropic.
Changelog
- 2026-10-04: created (resolved lead from the people-registry run)
People
Related posts (1)
- Karpathy: 'Personal update: I've joined Anthropic.' original ↗ Andrej Karpathy @karpathy · x · 2026-05-19
First-hand announcement of the most visible AI talent move of spring 2026; ~28M views, ~149K likes (fxtwitter, Oct 4, 2026).
Related events
- Andrej Karpathy coins "vibe coding" ★★★
- Andrej Karpathy's essay "Software 2.0": neural networks as a new way to write software ★★★
- Anthropic raises $65B Series H at $965B valuation, passing OpenAI ★★★★
- Anthropic: automated Claude researchers mitigate 10 alignment failures and nearly match production alignment of an Opus 4.8 checkpoint ★★★★
Sources (4)
- officialAndrej Karpathy on X: 'Personal update: I've joined Anthropic.'
- pressTechCrunch: OpenAI co-founder Andrej Karpathy joins Anthropic's pre-training team
- pressGizmodo: OpenAI cofounder Andrej Karpathy joins Anthropic as Sam Altman's fortunes turn
- discussionHacker News: I've joined Anthropic
id: 2026-05-19-karpathy-joins-anthropic · updated 2026-10-04 · open in the interactive timeline