Cloudflare Open-Sources Clef, an AI Decision Model That Answers With Probabilities Instead of Text
Cloudflare just gave away a decision model that reads text and images and answers with numbers, not paragraphs. The System 1 recipe now has a major infrastructure vendor behind it.
A message lands in a support queue: checkout has been failing for every customer for an hour. An AI agent needs three answers fast. Is it urgent, which team owns it, and how bad is it? On October 1, Cloudflare released a model built for exactly that kind of question, and it gave the weights away.
The model is called Clef, and it comes in two sizes. Clef has 27 billion parameters and Clef-flash has 9 billion. Both are free on Hugging Face under the Apache 2.0 license and also run on Cloudflare's Workers AI.
Numbers instead of paragraphs
Clef does not write. You give it a situation and a set of typed questions, such as yes or no, pick one, or rate on a scale, and it returns a probability for every allowed answer in one pass. It is built on frozen Qwen models with a small scoring head on top. Unlike Typesafe's Jev, which reads only text, Clef can also read images and video.
That is the same System 1 recipe we traced through Jev, OpenJev, Kev, and Laya. Now a major infrastructure company is shipping it close to users.
The performance claims are Cloudflare's own. In its tests, Clef-flash answered in a median of 38.8 milliseconds, against 524.1 for Jev, and Cloudflare says Clef leads most of its decision benchmarks. Nobody has reproduced those results yet, and Jev still wins several harder reasoning tests in Cloudflare's own tables. Hosted Clef also costs more, about $0.24 per million tokens versus $0.042 for Jev, according to The Register. Cloudflare told the outlet its training data is not public.
The real prize is inspectability. When we tested Jev as an LLM judge, its confidence dropped when it was wrong, which told us exactly which answers needed a second look. A paragraph never does that.
Cheap, fast, and checkable decisions are no longer one startup's secret. They are becoming standard equipment.
Sources
- Cloudflare Blog, "Introducing Clef: our open-source decision models, and new RL fine-tuning platform," Oct. 1, 2026
- Cloudflare Developers, "Introducing Clef: Cloudflare's first open-source decision models, now on Workers AI," Oct. 1, 2026
- Hugging Face, "Cloudflare/clef," accessed Oct. 2, 2026
- Hugging Face, "Cloudflare/clef-flash," accessed Oct. 2, 2026
- The Register, "Cloudflare tries to outplay Jev with open-weight Clef models," Oct. 1, 2026
- TokenPost, "Cloudflare Adds Its First Team-Trained Decision Models to Workers AI," Oct. 1, 2026