Xlsx

This is a comprehensive spreadsheet tool that handles the full lifecycle of Excel work: creating files with openpyxl, analyzing data with pandas, and recalculating formulas through LibreOffice. The standout piece is its opinionated guidance on financial modeling conventions (blue text for inputs, black for formulas, specific number formatting) and its absolute insistence on zero formula errors with a built-in verification script that scans for #REF!, #DIV/0!, and other errors. It's particularly aggressive about making Claude use actual Excel formulas instead of hardcoding calculated values in Python, which is the right call if you want spreadsheets that remain functional after creation. The documentation requirements for hardcoded assumptions are thorough, almost to the point of being tedious, but that's probably what you want in financial work.