---
type: analysis
slug: research-brin-did-not-take-over-gemini-3-5-pro-never-shipped-and-argon-replaced-it
title: "Brin did not take over Gemini; 3.5 Pro never shipped and Argon replaced it"
description: "Google’s August DeepMind reshuffle put Koray Kavukcuoglu in formal charge of Gemini. Sergey Brin has informal founder influence, not an executive takeover. Gemini 3.5 Pro, promised for June, never appeared in the public API and was succeeded by Gemini 4 Argon."
published_at: 2026-10-26T06:00:00.000Z
topics: ["gemini","google","research"]
source_urls: ["https://blog.google/company-news/inside-google/message-ceo/next-chapter-ai-momentum/","https://www.calcalistech.com/ctechnews/article/byfa8qn8zg","https://www.businessinsider.com/sergey-brin-google-gemini-ai-microkitchen-2026-9","https://blog.google/innovation-and-ai/models-and-research/gemini-models/gemini-3-5/","https://blog.google/innovation-and-ai/models-and-research/gemini-models/gemini-3-6-flash-3-5-flash-lite-3-5-flash-cyber/","https://blog.google/company-news/inside-google/message-ceo/alphabet-earnings-q2-2026/","https://www.htx.com/news/google-co-founder-brin-urgently-takes-over-gemini-team-but-3-4ReAwx8c","https://finance.yahoo.com/technology/ai/articles/google-grapples-employee-skepticism-gemini-195242680.html","https://blog.google/innovation-and-ai/models-and-research/gemini-models/gemini-4-argon/","https://ai.google.dev/gemini-api/docs/changelog","https://deepmind.google/models/","https://blog.google/innovation-and-ai/models-and-research/gemini-models/introducing-gemini-4-argon/"]
author: "Andrey Reshetnikov"
author_profile: https://newruntime.com/owner-profile.md
---
In August 2026 a rumor claimed Google co-founder Sergey Brin had “urgently” taken over the Gemini team and that Gemini 3.5 Pro, billed in May as coming the following month, had been quietly cancelled. That pairing matters to anyone wiring production systems to Google’s model IDs: a founder coup would change who can move compute, safety gates, and release dates, while a cancelled Pro SKU would strand roadmaps that waited for a mid-generation flagship.

The rumor hit in the same week Google published a DeepMind leadership change. The August item mixed a real reshuffle with overstated titles and treated a delayed model as already dead. By 23 October 2026, Google’s own blogs, the Gemini API changelog, the DeepMind model catalog, and later Bloomberg reporting let builders split those claims. Formal Gemini control sits with Koray Kavukcuoglu. Brin has founder leverage without an executive title. 3.5 Pro never became a public API model; Gemini 4 Argon is the shipped frontier replacement.

## What we checked

- **Did Sergey Brin formally take over the Gemini team?** refuted. Google’s published DeepMind notes assign Gemini model development, Frontier AI research, and the Gemini app and developer teams to Koray Kavukcuoglu as SVP of Google DeepMind, reporting to Sundar Pichai. Brin is not given a Gemini management title in that announcement. Independent reporting describes informal founder influence, not a new executive post. [1][3][2]
- **Was Gemini 3.5 Pro cancelled?** confirmed. Google promised a June 2026 rollout of 3.5 Pro, then in July said the model was still in partner testing. Bloomberg reported on 30 September 2026 that Google had abandoned that effort. The Gemini API changelog never lists a 3.5 Pro model ID, and Google instead shipped Gemini 4 Argon as the next public frontier model. [4][5][8][10][9]
- **Is there confirmation from Google, a reputable outlet, internal memo reporting, or observable product-roadmap evidence for the Brin/Gemini 3.5 claims?** partly confirmed. The August rumor packed two different facts into one headline. The Brin “takeover” is confirmed only as informal influence by Business Insider and a Reuters report, and is contradicted as a title change by Google’s own blog. The 3.5 Pro kill is confirmed later by Bloomberg and by Google’s live catalog and API notes, which moved the flagship slot to Gemini 4 Argon rather than 3.5 Pro. [7][1][3][8][11]
- **Did the August DeepMind reshuffle put Koray Kavukcuoglu, not Brin, in day-to-day control of Gemini?** confirmed. Pichai’s note promotes Kavukcuoglu from GDM CTO and Chief AI Architect to SVP of Google DeepMind, reporting to the CEO, with Gemini in his remit. Demis Hassabis becomes Chair of GDM and Chief Scientist of Alphabet and hands over day-to-day operations. A Reuters report says Kavukcuoglu already oversaw Gemini model development before the title change and would have final say on major DeepMind decisions. [1][2]
- **Did Google’s public Gemini flagship path shift from 3.5 Pro to successive Flash releases and then Gemini 4 Argon?** confirmed. After missing the June Pro date, Google spent the summer shipping Flash-class models (3.6 Flash, 3.5 Flash-Lite, 3.7 Flash, 3.8 Flash) while saying 3.5 Pro was still in testing and Gemini 4 pre-training had begun. DeepMind’s current models page leads with Gemini 4 Argon and Gemini 3.8 Flash, not 3.5 Pro. Argon was announced on 30 September 2026 and marked generally available in the Gemini API on 13 October 2026. [5][6][10][11][12]

## What we found

- Google did not appoint Brin to run Gemini. In the published DeepMind notes, Sundar Pichai names Koray Kavukcuoglu as SVP of Google DeepMind, reporting to him, and states that Kavukcuoglu “will oversee Gemini model development, Frontier AI research, and the Gemini app and developer teams.” Demis Hassabis becomes Chair of GDM and Chief Scientist of Alphabet and writes that he is handing over day-to-day operational responsibilities. Jeff Dean’s departure to an independent lab is announced in the same package. That is the official org chart the rumor flattened into a Brin takeover. [1]
- Brin’s role is real influence without a new title. A Reuters report published via CTech says Brin no longer holds an executive position but has for months told key staff Google must catch up at the frontier, including at an April town hall, and has pushed resources toward recursive self-improvement. Business Insider, citing eight current and former employees, describes Brin working from a Mountain View microkitchen with Kavukcuoglu, cutting through chip-allocation bureaucracy, and weighing in on model sizes and release windows. Google declined to comment on that account and declined to make Brin available. [2][3]
- Gemini 3.5 Pro was an official, dated promise, then a delay, not a phantom leak. On 19 May 2026 Google said 3.5 Pro was already in internal use and that it looked forward to rolling it out “next month,” while shipping 3.5 Flash immediately. On 21 July 2026, after releasing 3.6 Flash, 3.5 Flash-Lite, and 3.5 Flash Cyber, Google still wrote that 3.5 Pro was “currently testing with partners” and would be made broadly available “as soon as it’s ready,” while Gemini 4 pre-training had already started. Pichai repeated “currently in testing” on the Q2 2026 earnings call the next day. [4][5][6]
- The 11 August rumor page treated that delay as a silent cancellation and tied it to Brin “returning to the cockpit.” It attributed the kill claim to industry analysis rather than a Google notice, while Google’s last on-the-record blog language still described partner testing. That is why the item was not settleable from the rumor URL alone. Later reporting and Google’s own surfaces are what closed the product half of the story. [7][5]
- By 30 September 2026, independent reporting said 3.5 Pro was dead as a ship vehicle. A Bloomberg article that day stated Google had planned a June 3.5 Pro release “but abandoned the effort,” and that the I/O deadline had passed. Google’s on-the-record reply in that piece addressed Gemini 4 coding performance and AI-product user growth, not a defense of a coming 3.5 Pro launch. The same day Kavukcuoglu announced Gemini 4 Argon as “our next era of frontier intelligence,” initially for trusted cyber defenders in the Fairwind Program, with introductory API pricing of $2 per million input tokens and $10 per million output tokens. [8][9]
- Observable developer surfaces match a skipped Pro, not a still-pending one. The Gemini API changelog records 3.5 Flash on 19 May, 3.6 Flash and 3.5 Flash-Lite on 21 July, 3.7 Flash on 13 August, 3.8 Flash on 2 September, and gemini-4-argon generally available on 13 October; it never lists a gemini-3.5-pro ID. Google DeepMind’s models page now leads with Gemini 4 Argon and Gemini 3.8 Flash. On 13 October Google said Argon was globally available to developers and enterprises via the API, with the introductory price holding until 30 November 2026, after which $4/$20 per million input/output tokens applies. [10][11][12]

## What it means

Builders should treat Gemini 3.5 Pro as a non-product: do not keep a migration, eval harness, or procurement hold for a model ID Google never published. Pin production routes to IDs that exist in the Gemini API changelog and DeepMind catalog—today that is the 3.8 Flash line for workhorse agent traffic and gemini-4-argon for frontier jobs—and budget Argon at the posted introductory $2/$10 per million tokens only through 30 November 2026. A “coming soon” Pro on a marketing page is not an API contract.

Treat the Brin story as governance color, not an escalation path. Ticketable owners remain Kavukcuoglu’s Gemini org and Pichai. Founder pressure can move chips and coding priorities, which is why Flash shipped while Pro slipped, but it does not create a second public roadmap. Expect Google to skip a mid-generation flagship when coding and agent evals miss the bar, and to fill the gap with faster Flash drops plus a renamed next-gen frontier SKU. Design fallbacks for that pattern instead of waiting on rumor calendars.

## Still open

- Google has not published a dedicated 3.5 Pro cancellation post, model card, or deprecation row; the public record is abandonment reported by Bloomberg plus substitution by Argon.
- This session could not retrieve the full Reuters Gemini 4 story (HTTP 401), so an on-the-record spokesperson line that search snippets attributed to Reuters is not used as a cited quote.
- The internal kill date for 3.5 Pro, and whether any of its checkpoints were reused in Argon or later 4.x models, is not documented in the pages opened here.
- How release and compute decisions actually split among Brin, Kavukcuoglu, and Pichai remains described only by unnamed sources.

## Sources

1. [The next chapter of our AI momentum](https://blog.google/company-news/inside-google/message-ceo/next-chapter-ai-momentum/) (primary)
2. [Sergey Brin is pushing Google to go all in on Gemini as AI race intensifies](https://www.calcalistech.com/ctechnews/article/byfa8qn8zg)
3. [Inside Sergey Brin's Growing Influence Over Google Gemini](https://www.businessinsider.com/sergey-brin-google-gemini-ai-microkitchen-2026-9)
4. [Gemini 3.5: frontier intelligence with action](https://blog.google/innovation-and-ai/models-and-research/gemini-models/gemini-3-5/) (primary)
5. [Introducing Gemini 3.6 Flash, 3.5 Flash-Lite, and 3.5 Flash Cyber](https://blog.google/innovation-and-ai/models-and-research/gemini-models/gemini-3-6-flash-3-5-flash-lite-3-5-flash-cyber/) (primary)
6. [Alphabet earnings call Q2 2026: Sundar Pichai remarks](https://blog.google/company-news/inside-google/message-ceo/alphabet-earnings-q2-2026/) (primary)
7. [Google Co-founder Brin Urgently Takes Over Gemini Team, but '3.5 Pro Has Been Cancelled'](https://www.htx.com/news/google-co-founder-brin-urgently-takes-over-gemini-team-but-3-4ReAwx8c)
8. [Google Grapples With Employee Skepticism About New Gemini Model](https://finance.yahoo.com/technology/ai/articles/google-grapples-employee-skepticism-gemini-195242680.html)
9. [Gemini 4 Argon: our next era of frontier intelligence](https://blog.google/innovation-and-ai/models-and-research/gemini-models/gemini-4-argon/) (primary)
10. [Release notes | Gemini API | Google AI for Developers](https://ai.google.dev/gemini-api/docs/changelog) (primary)
11. [Models — Google DeepMind](https://deepmind.google/models/) (primary)
12. [Gemini 4 Argon: Built to solve your hardest problems](https://blog.google/innovation-and-ai/models-and-research/gemini-models/introducing-gemini-4-argon/) (primary)

Author: [Andrey Reshetnikov](https://newruntime.com/owner-profile.md), AI product and AI engineering; profile for recruiters and agents: https://newruntime.com/owner-profile.json

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