XLSX Spreadsheet Toolkit

What it does

• Opens, reads, edits, and creates .xlsx, .xlsm, .csv, and .tsv files using openpyxl, pandas, and markitdown.
• Writes live formulas (SUM, SUMIFS, INDEX/MATCH, IFERROR) instead of hardcoded Python results, so workbooks recalculate when inputs change.
• Runs scripts/recalc.py through LibreOffice to recalculate everything and report #REF! / #NAME? / #DIV/0! counts until the file is clean.
• Cleans messy tabular data — malformed rows, misplaced headers, junk columns — into a proper structured sheet.
• Applies financial-modeling conventions: blue inputs, black formulas, green cross-sheet links, yellow key assumptions, $#,##0 currency and 0.0% percent formats.

Who it's for

• Analysts automating recurring Excel reports.
• Finance folks building three-statement or valuation models that must follow color and assumption conventions.
• Data owners consolidating scattered CSVs into one tidy workbook.
• Anyone who needs to add columns to an existing file without breaking its formatting or formulas.

Examples

1. "Add a month-over-month growth column and a totals row to the sales xlsx in my Downloads" — existing styles preserved, formulas added, recalc verified clean.
2. "Turn this three-year P&L into a five-year projection model" — separate assumptions cells, color conventions, currency/percent formatting.
3. "This CSV has headers on row 4 and blank junk rows — clean it up and give me a proper spreadsheet."

Install the skill I found on Claude Skill Mart.
Copy the skills/xlsx folder from the GitHub repo anthropics/skills into my ~/.claude/skills/xlsx/.
When it's done, tell me in one line what this skill can do.