Clef is an open-source decision model from Cloudflare. It is a 27B multimodal model that turns a state and a schema of typed questions into decisions, reading states as text, JSON, images, or video and returning a probability for every allowed option of every question in a single forward pass. No free-form text generation or output parsing is involved, and the Clef API is fully compatible with Jev and SystemOne.
Clef
Open-source decision models from Cloudflare
Clef Introduction
Key Features
- 27B multimodal decision model that outputs probabilities for typed questions
- Reads states as text, JSON, images, or video
- Single forward pass returns probabilities for every allowed option
- No free-form text generation or output parsing required
- API fully compatible with Jev and SystemOne
- Open-source, with Clef and Clef-flash hosted on Workers AI
Use Cases
- High-speed classification tasks
- Agentic workflows that require structured decisions
- Fine-tuning decision models on custom data via reinforcement learning
Why Startups Use It
Startups building classification or agentic workflows can use an open-source decision model that returns structured probabilities in a single forward pass, avoiding free-form text generation and output parsing, with the option to fine-tune on their own data.
Frequently Asked Questions
What is Clef?
Clef is an open-source 27B multimodal decision model from Cloudflare that converts a state and a schema of typed questions into decisions with probabilities for each allowed option.
What input types does Clef support?
Clef reads states as text, JSON, images, or video.
Is Clef open source?
Yes, Clef and Clef-flash are open-source models hosted on Cloudflare Workers AI.
Is there a companion fine-tuning platform?
Cloudflare launched a reinforcement learning platform that lets developers fine-tune decision models using their own data.
More About Clef
PricingPaid
Listed DateOct 03, 2026
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