Definition
Plain language
An open-weight Mistral-based assistant model fine-tuned with preference learning.
As stated in the literature
A Mistral-7B-based assistant model post-trained with DPO on preference data, used as an open-weights aligned model in alignment research.
Why it matters: It is a widely shared, reproducible reference point in open alignment work, making method comparisons easier across labs.
For example, a researcher comparing new alignment methods might use Zephyr as a strong, freely available baseline DPO-tuned model.
Heard on the show
“The dissociation rests on two natural-experiment pairs — Llama-three-point-one to three-point-three, and Mistral to Zephyr — plus the controlled DPO experiment.”Episode 004 — The Sycophancy Circuit That Survives Alignment Training