XLSX Purpose Use this skill when a spreadsheet is the main input or output. It covers , , , and work: creation, editing, cleaning, formatting, charting, formula construction, validation, and analysis. Workflow 1. Identify the spreadsheet task: read/analyze, clean/restructure, create, edit existing workbook, add formulas, build a financial model, chart, convert, or validate. 2. Use pandas for tabular analysis and transformation. 3. Use openpyxl for formulas, formatting, workbook structure, sheets, styles, and existing Excel files. 4. Prefer formulas in the workbook over hardcoded Python-calcul…