Incremental-sync cursor. Returns only candidates whose changed_at is strictly greater than this timestamp. changed_at covers both the candidate record and its interview calls, so interview results, transcripts, statuses, tags and evaluations landing on an existing candidate are picked up even when the candidate record itself is untouched. Internal bookkeeping writes do not move the cursor. Accepts a full ISO-8601 timestamp (preferred) or YYYY-MM-DD, read as midnight UTC; anything else is a 400. Advance your cursor to a timestamp captured before the poll started, minus a 5-minute safety lag. Never advance to max(changed_at) — results are ordered by created_at, so a row changed mid-poll can land on a page you already passed, and a cursor set to the maximum skips it permanently. The cursor cannot report deletions (no tombstones) or edits to job fields.