Clef is a set of open decision models from Cloudflare: instead of writing text, they answer fixed questions with a probability for each allowed choice.
In plain words
A decision model returns typed answers with probabilities that a program can act on, for example to route a support ticket or hand a case to a person. Clef is a 27-billion-parameter model that can read text, JSON, images or video, and it was post-trained from Qwen3.8-27B. Clef-flash is a smaller, faster version. Cloudflare hosts both on Workers AI and publishes them on Hugging Face under the Apache 2.0 licence, and their API is compatible with Jev and SystemOne.
A quick example
Cloudflare's Threat Intelligence team has been testing Clef to sort website domains. For one domain it might report a 95% chance of fashion, 85% ecommerce and under 1% phishing, and Cloudflare says one such check took 2.2 seconds.
Where you'll meet it
- Routing tickets, escalating cases or passing them to a person in agent workflows.
- Sorting website domains into categories.
Related
Sources
- DocsClef: open-weight decision models, Cloudflare · read 6 Oct 2026
- DocsCloudflare/clef, Cloudflare (Hugging Face) · read 6 Oct 2026
- Docsclef, Cloudflare Workers AI docs · read 6 Oct 2026
Checked by WhatIsAI against the sources above · 6 Oct 2026. A full five-minute explainer with a diagram may follow. Spotted an error? Report it.