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Justus Mattern

Verified account Proximal

@MatternJustus

cofounder @ProximalHQ
San Francisco, CA justusmattern.com Joined March 2021
953 Following 9.2K Followers 1.3K Posts

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Justus Mattern Verified account @MatternJustus
If I had to name one thing that we’ve done right at Proximal, it would be hiring.

Outside of raw technical talent, I’ve never seen a place at which people care as much and have as much fun together (I’ve been told that coming to the office feels like going back to college)
Proximal @ProximalHQ Sep 29
Proximal builds infrastructure that enables AI to improve from real-world experience.

In the past year, we have grown to more than $200M in annualized revenue helping frontier labs and enterprises improve coding agents. Now, we are expanding beyond software engineering.

Recent progress in mathematics demonstrates what happens when models are trained in domains with massive amounts of public data and easy verifiability, making it easy to find weaknesses, generate training tasks, and iterate quickly.

We build infrastructure that enables this feedback loop in other domains: we are excited about a world in which AI systems design targeted drugs, accelerate chip design, and rewrite legacy software that still runs hospitals, power grids, governments, and other critical infrastructure.

Since starting, we have assembled a small team of researchers and engineers and built world-class infrastructure for post-training and synthetic data research to overcome the challenges of scaling manual data curation.

Our team comes from Cursor, Google DeepMind, Meta Superintelligence, Prime Intellect, Citadel, and Jane Street. More than half are former founders.

We’re fortunate to be backed by investors who share that vision, including @generalcatalyst who led our $15M Seed Round at a $300M valuation, as well as @chemistry, @svangel, @dvlamoen and individuals like @LiamFedus, @kevinweil, and @bernhardsson
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Justus Mattern Verified account @MatternJustus
Congratulations to @thinkymachines!

I love to see the level of thoroughness and attention to detail when it comes to Inkling's evaluation methodology.

Also excited to see some of the auto-research evals we have been working on featured in the blog!
Thinking Machines Verified account @thinkymachines 2d
Introducing Inkling 2 Small. Scoring 31 on the AA Intelligence Index, it's a big jump over its predecessor.

Inkling 2 Small is available for fine-tuning and inference on Tinker today, with full weight release planned soon.

thinkingmachines.ai/news/inkling-2…
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Justus Mattern Verified account @MatternJustus
Congrats on ths strong release! Great to see progress on FrontierSWE :)
Sundar Pichai Verified account @sundarpichai Oct 28
I did say we'd be releasing our models periodically...introducing Gemini 4 Carbon, our next frontier model.

Following Argon's release just two weeks ago, Carbon shows the pace at which we’re pushing the frontier, it ranks #1 on the recently updated v5.0 of @ArtificialAnlys Intelligence Index at 59. It also leads across key cybersecurity evaluations scoring 88.2% on SEC-bench Pro for finding vulnerabilities, 54.8% on ExploitGym for exploitation, and 71.0% on CWE-bench for patching.

We’re seeing significant improvements in long-horizon tasks even compared to Argon, and we’ve strengthened frontier safeguards.

As we did with Argon, we’re going to roll it out gradually + responsibly. Some trusted cyber defenders will get access starting this week. We'll be expanding it to more partners through our Fairwind Program, ahead of wider availability soon, so hang tight!
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Justus Mattern Verified account @MatternJustus
Congrats! Aryaman and I met as undergrads at NAACL 2022, so I've been lucky enough to have a front-row seat to his PhD journey and watch him become a leading interpretability researcher.

Outside of this, he is a great person. I'm sure he will do extremely well at Anthropic!
Aryaman Arora Verified account @aryaman2020 Oct 17
I defended my Ph.D. @stanfordnlp a few months ago, and recently started @AnthropicAI on the Interpretability team!

(pictured: my awesome defence committee members)
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