What problem does it solve? Creating spreadsheets by hand often leads to hardcoded totals, broken formulas, and placeholder data that make files unreliable for real financial or operational use. This Skill enforces disciplined spreadsheet design so every generated workbook uses live formulas, real data, and clean multi-sheet structure. ## Core Features & Use Cases - Formula-first generation: Totals, percent shares, growth rates, and lookups are written as Excel formulas (SUM, VLOOKUP) rather than precomputed numbers, so users can tweak inputs and watch results update. - Structured multi-sheet workbooks: Supports six spreadsheet kinds (data, budget, tracker, schedule, report, comparison) with conventions for summary sheets, assumptions sheets, frozen headers, and column widths. - Format and error compliance: Enforces currency, percent, date, and text formats while guaranteeing zero formula errors like #REF!, #DIV/0!, or #N/A. - Use Case: Ask for a quarterly budget and receive a workbook with category-by-period sheets, a totals row computed by =SUM formulas, a variance column, and a separate Assumptions sheet driving the calculations. ## Quick Start Ask the assistant to create a budget spreadsheet with real expense categories, formula-based totals, and a separate assumptions sheet using the xlsx skill.