CellType

We're building the agentic drug company. Foundation models + AI agents that simulate human biology to discover drugs. Backed by Y Combinator (W26).

[David van Dijk @david_van_dijk]

Our paper STRIDE was accepted to ICML 2026!

We post-train LLMs to optimize proteins & molecules by emitting a chain-of-thought of atomic edits (INSERT / DELETE / REPLACE). Levenshtein-shortest-path SFT + GRPO-style RL. Boosts protein optimization success from 42% → 89%.

[David van Dijk @david_van_dijk]

Our paper Soft-Rank Diffusion was accepted to ICML 2026!

Prior permutation-diffusion methods use riffle-shuffle forward processes that are abrupt and scale poorly with n. We instead lift permutations to continuous soft ranks in [0,1]ⁿ and run a reflected Brownian bridge, paired with a contextualized Plackett–Luce decoder. Big gains on long-sequence sorting and TSP.

[Y Combinator @ycombinator]

AI-Personalized Medicine
@agupta

The cost of genome sequencing has fallen faster than Moore's Law, and agents can now analyze personalized health data to generate highly accurate, user-specific suggestions.

We think these shifts will bring about a revolution in care delivery, and a wide variety of startups will support every step of that ecosystem.

[David van Dijk @david_van_dijk]

We’re hiring a Founding Head of Strategy, Data & Partnerships at @CellTypeInc

We’re building a biological world model — foundation models that simulate human biology and power the agentic drug company.

Help take this into the world.

Strategy × data x partnerships × frontier biotech/AI

🔗 https://t.co/81ffQBxxbg

[CellType @celltypeinc]

CellType is hiring founding engineers! Biology is one of the biggest unsolved frontiers for AI. Join us building foundation models and agentic systems for drug discovery. If you want to push the frontier of AI for science, we'd love to talk.

https://t.co/Bjj7yIS9nn

[David van Dijk @david_van_dijk]

Excited for YC Demo Day!

[CellType @celltypeinc]

Great finally meeting Taylor Hsu from Senhwa Biosciences in person in San Francisco. Their drug CX-4945 was identified in our screen out of 4,000 compounds. Now CellType and Senhwa are partnering to further develop it together — exciting things in the pipeline!
https://t.co/setuKMGxdG

[CellType @celltypeinc]

This is the thesis behind @CellTypeInc. You can't just prompt an LLM to design a drug. You need a simulator that can evaluate whether a design actually works—and then use that feedback to train models that get better at the hard direction.

Paper: https://t.co/3DgpyY7MPf

[CellType @celltypeinc]

LLMs can ace science exams and explain complex mechanisms. But can they actually do science—design a molecule, a dosing regimen, or a gene circuit that works?

We built SciDesignBench, a benchmark for testing frontier LLMs on scientific design tasks grounded in real simulators. The core finding is that models that can talk fluently about science still struggle when asked to produce designs that actually satisfy quantitative targets. We also propose a simulator-feedback RL recipe that improves performance on these tasks.

Paper: https://t.co/PqxmdPrGii 🧵

[CellType @celltypeinc]

The elegant part is that the same asymmetry that makes inverse design hard also suggests the fix. Scientists have already built forward simulators for many of these problems. Those simulators can be repurposed as RL environments: propose a design, evaluate it, learn from the reward.

In our case studies, training on simulator feedback lets a small 8B model outperform much larger frontier models on selected scientific design tasks.

[David van Dijk @david_van_dijk]

Our first clinical-stage pharma partnership. CellType models working on a real drug, in real patients. This is what we built for.

[CellType @celltypeinc]

We are thrilled to announce CellType's strategic partnership with Senhwa Biosciences! We're using our models to accelerate their clinical oncology drug, CX-4945, unlocking novel mechanisms to make tumors more visible to the immune system. https://t.co/FooliO4wU8

[CellType @celltypeinc]

Keep working in your local environment while CellType Agent Pro offloads heavy GPU jobs to CellType Cloud.

Run protein folding, molecular simulations, single-cell models, and other GPU-heavy bio workflows without managing your own GPU stack.

Try it at https://t.co/1y8ysuTatK

[CellType @celltypeinc]

People kept telling us they wanted to run the CellType Agent but didn't have the compute. So we built CellType Agent Pro — GPU compute, plus an on-prem option for teams with sensitive data.
https://t.co/1y8ysuTatK

[Ankit Gupta @agupta]

This team of Yale CS Professor + postdoc is building a next-gen drug company. It's been great working with them this batch. Congrats on the launch!

[CellType @celltypeinc]

@Jan_Haris_ Live now! pip install celltype-cli (requires Python 3.10 and above) then run ct, it'll walk you through setup.

[CellType @celltypeinc]

We teach models to reason about biology.

Today we're open-sourcing the tool we built to run that science.

Think Claude Code, but for drug discovery.

pip install celltype-cli

[CellType @celltypeinc]

@dagarfield This is fixed now, we pushed to PyPI shortly after launch. Run pip install celltype-cli (requires Python 3.10+)

[CellType @celltypeinc]

@jboysen0 pip install celltype-cli now pulls in all deps correctly. Thanks for flagging this early.