What should I prompt Claude (or another AI) to do when tailoring my resume to a job description?

Upload your resume and the job description, then ask it to: (1) keep all bullets truthful and accurate, (2) update wording to match the ATS keywords in the job description, and (3) flag any gaps — skills or experiences the job requires that aren't represented in your resume. That tells you exactly where you need to add or strengthen a bullet.