Excel (xlsx) skill for Claude
Reviewed by Sophie Filer · Updated 27 Oct 2026
Builds and edits Excel workbooks that keep their formulas, then checks them for errors.
The common failure with AI spreadsheets is hard-coded numbers: the totals look right until you change an input. This skill tells Claude to write real formulas, then recalculate the workbook and scan every cell for errors before handing it over.
It also brings sensible house rules for financial models, such as colour-coding inputs versus calculations and keeping assumptions in one place, which makes the files much easier for a person to audit.
When Claude reaches for it
- Creating a spreadsheet, model or tracker from scratch
- Cleaning up or restructuring a messy CSV or xlsx file
- Adding formulas, columns or charts to an existing workbook
What is in the pod
- Working rules for formulas, formatting and model layout
- Guidance on when to use pandas for analysis and openpyxl for editing
- A recalculation script that runs the workbook through LibreOffice and reports any errors
Planting it
Claude Code
- Add the Anthropic skills marketplace once.
- Install the document-skills plugin, which includes xlsx.
- Start a new session. Claude loads the skill on its own when a task matches.
/plugin marketplace add anthropics/skills
/plugin install document-skills@anthropic-agent-skillsClaude apps (web, desktop, mobile)
- On a paid plan, turn on code execution and file creation in Settings.
- The document skills are built in, so there is nothing else to add.
What it needs
- Python 3 with openpyxl and pandas
- LibreOffice, for the recalculation check
Notes from the pea patch
- Tell it whether the file is for you or for someone else. It formats a shareable model more carefully.
- If your company has its own template, hand it over first. The skill is told to follow an existing file before its own defaults.