This document presents a proposed design for a customer segmentation interface tool. The tool allows marketers to easily define and edit customer segments through a simple compose field, without needing SQL knowledge. Marketers can create new segments, edit existing segments, and reference previous segments. The design aims to let marketers focus on marketing tasks, adapt segments easily, and see segment results in real time. A sample workflow takes a marketer through creating, editing, and referencing segments to target different customer groups.