AI-assisted demonstration using synthetic data, not client work. A Python script merges compatible CSV files by an explicit key, removes only exact duplicate occurrences, and sends conflicting or missing-key records to review. The verified example accounts for all 10 input records: 4 clean, 4 for review and 2 duplicates removed. Original files, leading zeros and multiline text are preserved. Six tests passed. Source code, sample outputs, an audit trail and rerun instructions are available.