Cloudflare Clef powers zero-cost email triage on rental server

The project started because spam was burying real inquiries from a company's web contact form, and the existing environment was a rental server that could not host an always-on process or a database. Rather than rebuild the stack, the developer leaned on what was already there: Cloudflare for DNS, Sakura Internet for mail, Go for a small binary, and Cron to run it every few minutes. The piece is a firsthand account of that constraint-driven design choice, not a product announcement.

What made it possible was a decision model rather than a text generator. Clef accepts text, JSON, images, or video as a state and returns probabilities for a defined question schema, so the developer could ask "is this an inquiry relevant to our company?" and get a score back. Workers AI serves @cf/cloudflare/clef, a 27B multimodal model, through its free tier, which the author notes keeps inference cost essentially zero at low mail volumes.

The operational result is modest but concrete: the score in the Subject line replaced manual scanning of the spam folder. The author argues the same pattern may lower the barrier to AI adoption for small setups, since Clef is specialized for judgment rather than generation and fits this kind of automated triage work well.