Google loses the engineers who built modern AI: Jeff Dean departs with three top scientists for Discovery Loop as Hassabis steps into chair role

Jeff Dean, who cofounded Google Brain and served as technical co-lead on Gemini, is leaving Google after 27 years alongside three of the company's top AI scientists to launch Discovery Loop, a startup building AI that automates the scientific method 1.

Until recently, Dean, Oriol Vinyals, and Noam Shazeer had co-led Gemini's development 2. Shazeer left for OpenAI in June. John Jumper, who shared a 2024 Nobel Prize with DeepMind head Demis Hassabis, departed for Anthropic the same week 2. Now Dean and Vinyals are walking out. All three Gemini co-leads have left Google inside a single summer, and Google is writing the check for the company they left to build.

The four scientists departing for Discovery Loop are Google Fellow Sanjay Ghemawat, Google Brain cofounder Quoc Le, DeepMind VP of research and Gemini technical lead Oriol Vinyals, and Dean himself, who was Google's 30th employee when he joined in 1999 3 4. Dean reportedly plans to serve as CEO 4.

The same day, Sundar Pichai announced that Hassabis will step down as Google DeepMind CEO to become chair of Google DeepMind and Alphabet's chief scientist, with CTO Koray Kavukcuoglu promoted to SVP of DeepMind running daily operations 3. Hassabis will have few direct reports in the new role, according to an Alphabet spokesperson who spoke with Reuters 2. Alphabet shares fell 4% on the news 2.

What Discovery Loop is building

Discovery Loop is structured as a public benefit corporation that aims to automate the scientific method 4. The vision is AI that proposes experiments, implements them, runs them, evaluates the results, and iterates thousands of times over 1. The company had already been formed in secret 1.

The founders plan to be their own first customer. The initial experiment loops will target their own machine learning algorithms, with the improved software then applied to drug discovery, chip design, and materials science 1. The founders have not disclosed the funding amount or valuation 1.

Khosla Ventures and Radical Ventures co-led the funding round, with Kleiner Perkins, Lightspeed, and Doerr Capital also participating 4. Google is a founding investor and will provide compute through Google Cloud for the first year 3. Pichai tried to keep the group at Google through multiple meetings before accepting their departure 1. Vinod Khosla, whose firm co-led the round, said: "Humans have been using AI to do research, not using AI to be a researcher. The fundamental thing is that AI is the researcher" 1.

What Google actually loses

The four departing scientists built or co-built nearly every foundational layer of Google's AI stack:

• Dean and Ghemawat designed large parts of the search and distributed computing infrastructure that still powers Google's products today 1.
• Dean and Le cofounded Google Brain in 2011, the unit that drove Google's machine learning program before its 2023 merger into DeepMind 2.
• Dean and Vinyals held two of the three Gemini technical co-lead seats 2.
• Le led AutoML-Zero, a project that uses machine learning to autonomously build AI systems 1.

Hiring replacements does not address what these departures actually remove. Institutional knowledge, the hard-won understanding of why systems work the way they do, lives in the people who built them. It does not fully transfer through documentation or onboarding decks. WIRED describes the four founders as longtime colleagues and friends who vacation together, and Dean told the publication the company's concept crystallized in a matter of weeks because they already shared a working understanding of the problem 1.

The timing sharpens the stakes. The flagship version of Gemini 4 remains unreleased despite a planned June launch, fueling investor concerns that Google is falling behind Anthropic and OpenAI 2. Under the departed co-leads' direction, Google released Gemini 3 last November, which the industry widely saw as closing the gap with rivals 2. Brian Mulberry, chief market strategist at Zacks Investment Management, told Reuters: "Getting innovation and execution back online is not going to be easy and losing key contributors won't make it any better" 2.

The question for Google is not whether it can hire talented engineers. It can. The question is whether the tacit knowledge that made Gemini 3 competitive transfers at all, or whether it left the building with four people who already know how to work together.