Candidate attribute types are the structured attribute dictionary on a job — the per-job catalogue of evaluable traits (e.g. JavaScript, Leadership, Years of experience) that get rated on scorecards and that AI matching uses to score candidate fit. Distinct from custom fields: custom fields are free-form data attached to a candidate, while attribute types are typed, job-scoped traits whose values live on job_candidate_attributes (the job-level catalogue entry), focus_candidate_attributes (which attributes a given interview kit focuses on), and scorecard_candidate_attributes (the interviewer's rating of a candidate on each attribute). Today this endpoint is site-admin-only.