Clef: our open-source decision models

Cloudflare has released two open-source decision models called Clef and Clef-flash that produce fast, deterministic outputs for classification tasks, addressing a different use case than large language models. Unlike LLMs, these decision models are designed to work consistently across any inputs without retraining and are now available on Workers AI and Hugging Face under an Apache 2.0 license. Clef leads the Jev Decision Index benchmark and demonstrates practical speed advantages—classifying website domains in 2.2 seconds compared to 4.7 seconds for competing LLM approaches.