Ben Kunkle

Zed Uses Student Models to Filter Production Traces for Zeta 2

Ben Kunkle, Zed’s edit predictions lead, explains how the company built Zeta 2 as a small production model for one latency-sensitive task: predicting a user’s next code edit on every keystroke. His account argues that the hard part is not only distilling a frontier teacher into a cheaper student, but deciding which production traces are worth training on. Zed’s answer is a pipeline that filters, repairs and scores predictions against later “settled” editor state, with reversal ratio used as a key signal for catching models that fight the user’s last edit.