Cloudflare introduced Clef and Clef-flash on October 1, the first models trained by its Workers AI team. They are decision models, not chatbots: instead of generating text, each reads an input state plus a schema of typed questions (yes/no, multiple choice, or rubric-scored) and returns a probability for every allowed answer in one pass. Agents get a structured decision they can act on immediately — route the ticket, block the request, escalate to a human — with no free-form output to parse.

Both models are hosted on Workers AI and published as open weights under an Apache 2.0 license. Clef runs on a 27B-parameter base with a 64k context window; Clef-flash is 9B and reports a median latency of about 39 milliseconds. They are compatible with TypeSafe AI's Jev System One API, so existing Jev integrations can swap endpoints, and unlike Jev they accept images and video — a decision can be triggered by a camera frame. Cloudflare also launched an RL fine-tuning service so customers can tune Clef on their own workloads.

The timing is pointed: Clef landed the same day AWS shipped Strands Decider 2B, its own open-source Jev rival. The category TypeSafe AI named "System One models" at its September 15 launch is hardening into a recognizable infrastructure tier rather than remaining a single vendor's idea.