Nathan Lambert
Center for Security and Emerging Technology (CSET)
A mix of a trip report and reading the open model research ecosystem.

I think about:

I think about:
This talk:




An LLM today is: weights + tools + harness
The model alone is no longer the product.

An LLM today is: weights + tools + harness
The model alone is no longer the product.
GPT-OSS is a great example of a successful, tool-oriented open model. Many more such models have emerged with the rise of OpenClaw et al. An exciting area for agents that run just at the cost of electricity (e.g. on a DGX Spark).

An LLM today is: weights + tools + harness

“Post-training” as a field to craft models is maturing into two sections:
This is new and very exciting to me (but not what this talk is about)!


The American Truly Open Models (ATOM) Project was a memo and community movement launched in the summer of 2025 to galvanize support for open models built in the U.S. At the time of launch, Kimi K2, Qwen 3 Coder, GLM-4.5 and StepFun Step 3 had shown that the Chinese ecosystem was producing excellent open models and the U.S. labs had little to show for it.

American Truly Open Models (ATOM).
Support for The ATOM Project

American Truly Open Models (ATOM).
Support for The ATOM Project
Methods research in The ATOM Report






All models with >5 downloads, derived from likes of Qwen, Llama, Mistral, etc. models. China 10% → 70% of derivatives. Europe 58% → 4%. Derivative share leads downloads as a forward signal.


Tracking top 10 open models per month, and their share of inference on OpenRouter. China 2.8% (Nov '24) → 72.7% (Jan '26).






153.6M in February for Qwen vs 71.2M for the next eight orgs combined.

The top 5 small Qwen3 models dominate monthly download numbers (again, February).



DeepSeek = 47% of 250B+ downloads. Two coexisting strategies: Qwen breadth across sizes, DeepSeek flagship at the frontier.


To learn more about the open models I cover:
Trip report: https://www.interconnects.ai/p/notes-from-inside-chinas-ai-labs
Labs visited:

Our visits were primarily formal, so the labs were not likely to give incendiary takes about competitors or sensitive topics (e.g. distillation). Some commonalities emerged.

Our visits were primarily formal, so the labs were not likely to give incendiary takes about competitors or sensitive topics (e.g. distillation). Some commonalities emerged.


Read more on Interconnects: The distillation panic · How much does distillation really matter?

Read more on Interconnects: Open models in perpetual catch-up · Reading today’s open-closed performance gap

The future of the open ecosystem, and strong open models in the next 1-2 years is largely an economics question – how long can companies raise? How long can companies dedicate compute to building open models which can be monetized more effectively elsewhere? Will the open ecosystem coordinate better and unlock further efficiency?
I’m stressed about this! Folks that want open models to be viable need to speak up now and often.
Read more on Interconnects: How open model ecosystems compound
Slides: https://natolambert.com/slides/china-atom-2026/talk.html
More: atomproject.ai/report · arxiv.org/abs/2604.07190 · interconnects.ai · @natolambert · nathan@natolambert.com



Relative Adoption Metric (RAM) normalizes open model downloads by model size and time since release.
RAM = model cumulative downloads ÷ median downloads for top peers in the same size bucket






GPT-OSS surpassing Mistral’s entire legacy portfolio. Nemotron’s ramp accelerating. Disruption is still possible.
