xlsx (Excel)

What it does

A skill for Excel spreadsheets (.xlsx, .xlsm, .csv, .tsv): creating them from scratch, reading and editing existing ones (adding columns, computing values, formatting, charting, cleaning messy data) and converting between formats. The core principle is live formulas rather than hardcoded numbers, so everything recalculates when the inputs change. A pre-built Anthropic skill.

How to set it up

• claude.ai / Claude API — pre-built and available immediately (skill_id xlsx in container on the API).
• Claude Code — via the document-skills bundle:

/plugin install document-skills@anthropic-agent-skills

When to use it

• A financial model, report or dashboard in Excel with formulas and charts.
• Cleaning and restructuring a broken .xlsx/.csv (malformed rows, junk data, misplaced headers).
• Analysing tabular data where the deliverable has to be a spreadsheet file.

Example

"Build a 12-month P&L with formulas and a revenue chart" — you get a workbook where the total cells are real Excel formulas and the chart is bound to the data.