Psychological assessment is an integral aspect of training in graduate school. Developing ecologically integrated and culturally sensitive diagnostic tools to support case conceptualization and differential diagnosis is critical to improving assessment practices. Nevertheless, there is a dearth of research on diagnostic training practices, particularly when integrating the cultural context into an assessment. The current study addressed this gap by evaluating four novel diagnostic tools used to guide doctoral externs (n = 11), including case conceptualization and differential diagnostic tables, an attention-deficit/hyperactivity disorder (ADHD) matrix, and a specific learning disorder (SLD) in reading matrix. These tools were designed to integrate a range of clinical data from an ecological context. The current study (1) evaluated extern perspectives on the use and benefit of the diagnostic tools in their training and (2) discussed tool adaptation based on extern feedback. Data were analyzed via frequencies of extern responses to items. The results demonstrated high extern acceptability of the diagnostic tools and that the tools supported their ability to integrate the clients' ecological context into the diagnostic process. Adaptations of the tools in response to extern feedback are discussed. These tools can support culturally and ecologically sensitive assessment practices.