Xlsx

This handles the full spreadsheet workflow: reading data with pandas, creating and editing files with openpyxl, and most importantly, recalculating formulas through LibreOffice so you're not just writing formula strings into cells. It enforces zero formula errors as a hard requirement and ships with detailed guidelines for financial modeling (blue for inputs, black for formulas, proper number formatting). The recalc.py script scans every cell for errors and returns JSON with locations, which matters because openpyxl alone won't catch broken references or division by zero. The documentation is opinionated about using Excel formulas instead of hardcoding Python calculations, which keeps spreadsheets dynamic. Use this when you need Claude to build actual working models, not just dump data into cells.

skills.sh installs: 258
GitHub stars: 3.7K
last updated: Aug 21, 2026

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Install

$ npx -y skills add davepoon/buildwithclaude --skill xlsx --agent claude-code

Installs into .claude/skills of the current project.

Files

Requirements for Outputs

All Excel files

Zero Formula Errors

Every Excel model MUST be delivered with ZERO formula errors (#REF!, #DIV/0!, #VALUE!, #N/A, #NAME?)

Preserve Existing Templates (when updating templates)

Study and EXACTLY match existing format, style, and conventions when modifying files
Never impose standardized formatting on files with established patterns
Existing template conventions ALWAYS override these guidelines

Financial models

Color Coding Standards

Unless otherwise stated by the user or existing template

Industry-Standard Color Conventions

Blue text (RGB: 0,0,255): Hardcoded inputs, and numbers users will change for scenarios
Black text (RGB: 0,0,0): ALL formulas and calculations
Green text (RGB: 0,128,0): Links pulling from other worksheets within same workbook
Red text (RGB: 255,0,0): External links to other files
Yellow background (RGB: 255,255,0): Key assumptions needing attention or cells that need to be updated