The MacArthur Competence Assessment Tool for Criminal Adjudication (MacCAT-CA) has a strong psychometric profile, but the decision on whether to use it still requires a nuanced consideration. Assessment of Competency to Stand Trial is the most common forensic mental health referral. Selecting the correct tool to support decision-making regarding the issue of a defendant’s competence to proceed is a primary consideration when preparing to conduct a competency evaluation. The MacCAT-CA can sharpen an opinion, expose deficits that would otherwise go unnoticed, and lend defensibility to testimony, but only when its use is matched to the referral question, the defendant's clinical presentation, and the legal question at issue.