xlsx

Process and produce .xlsx, .xlsm, .csv, and .tsv spreadsheet files with formulas and validation.

Updated Aug 27, 2026
One-click install
npx skills add https://github.com/alexaundre/mycc --skill xlsx-alexaundre
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: xlsx
Source: https://github.com/alexaundre/mycc/tree/main/.codex/skills/xlsx
Command: npx skills add https://github.com/alexaundre/mycc --skill xlsx-alexaundre

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill requires openpyxl, defusedxml, lxml, and includes scripts (resource) components.

What problem does it solve?

Many tasks that involve tabular data require working files in Excel formats but users face errors, broken formulas, inconsistent templates, or messy tabular inputs that are hard to clean and validate by hand. This Skill centralizes reliable spreadsheet workflows so users can open, clean, modify, convert, and produce fully functional .xlsx/.xlsm/.csv/.tsv deliverables with formula integrity and preserved formatting.

Core Features & Use Cases

  • Read and write Excel and tabular files while preserving templates and formatting conventions.
  • Insert and maintain Excel formulas (avoid hardcoding calculated results) and run mandatory formula recalculation with LibreOffice via scripts/recalc.py to ensure zero formula errors.
  • Clean and restructure malformed tabular data (malformed rows, misplaced headers, junk data), convert between .csv/.tsv and .xlsx, and create new workbooks with professional fonts and number formats.
  • Validate Office package structure (unpack/pack), run XML/XSD and relationship checks, and auto-repair common issues when modifying Office files.
  • Use case examples: repair a downloaded financial model ensuring no #REF! errors, convert a messy CSV export into a templated workbook with formulas, or generate a multi-sheet forecast workbook that stays recalculable.

Quick Start

Open the spreadsheet at /path/to/input.xlsx, clean and restructure the data, add or convert formulas as needed, run the LibreOffice recalculation script, and save the validated output as /path/to/output.xlsx.

Frequently Asked Questions about xlsx

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I clean malformed CSV data and convert it into a formatted Excel workbook?▼

To clean malformed CSV data, the spreadsheet processing workflow restructures misplaced headers and junk rows, then converts the sanitized tabular data into a templated .xlsx workbook with professional fonts, number formats, and functional Excel formulas.

How do I repair a broken Excel file with formula errors like #REF!?▼

Repairing a broken Excel file involves unpacking the Office package, running XML and relationship validation checks, auto-repairing common structural issues, and recalculating formulas via LibreOffice to eliminate errors like #REF! and ensure a validated .xlsx deliverable.

Can I add Excel formulas without hardcoding the calculated values?▼

Yes, you can insert and maintain dynamic Excel formulas instead of hardcoding calculated values, and the workflow mandates a LibreOffice recalculation step to ensure the output spreadsheet contains zero formula errors and displays correct results.

Does openpyxl support converting spreadsheets between xlsx, xlsm, csv, and tsv formats?▼

Yes, the openpyxl-based workflow supports reading, editing, and converting between .xlsx, .xlsm, .csv, and .tsv tabular formats while preserving existing templates, formatting conventions, and formula integrity throughout the conversion process.

What is the best way to validate Office package structure after modifying an Excel file?▼

The best way to validate Office package structure is to unpack the file, run XML/XSD and relationship checks against the internal components, and apply common auto-repairs to ensure the modified Excel file remains a fully functional and valid deliverable.

Why do my spreadsheet formulas show errors after editing an xlsx file programmatically?▼

Spreadsheet formulas show errors after programmatic editing because the cached calculation results become stale, which is why a mandatory LibreOffice recalculation script must be run to refresh and validate all formula outputs before saving the final xlsx file.