The overarching goal of this study is to pilot test a peer-delivered decision support intervention (in the form of decision coaching) that is designed to enhance emerging adults' treatment decision-making and service engagement after enrollment in a coordinated specialty care (CSC) program. Based on an experimental therapeutics approach, this mixed methods pilot trial will assess feasibility, acceptability, and the intervention's potential impact on key decision-making needs (i.e., decision-making targets). We will track feasibility data related to study and intervention procedures, and collect acceptability and outcome data from 20 emerging adults who will participate in the intervention after enrollment in the CSC program. Quantitative analysis related to decision-making targets will provide preliminary evidence regarding whether the intervention impacts these targets, while qualitative analysis will explain how it may do so. Merged results from these two sets of data will inform intervention refinement by providing a nuanced understanding of the intervention's potential to engage decision-making targets from the perspective of emerging adults.