Overview
xlsx is an open-source backend skill for Claude Code and compatible agents, published by anthropics. Its author describes it as: “Use this skill any time a spreadsheet file is the primary input or output. This means any task where the user wants to: open, read, edit, or fix an existing .xlsx, .xlsm, .xltx, .csv, or .tsv file (e.g., adding column…”. The project has 177k stars on GitHub and ships custom license terms, so review them before reuse. Add it to your setup with `/plugin marketplace add anthropics/skills`.
What xlsx does
| Task | Approach | |---|---| | **Create** or **edit** with formulas/formatting | `openpyxl` — see gotchas below | | **Bulk data** in or out | `pandas` (`read_excel`, `to_excel`) | | **Quick look** at a sheet | `markitdown file.xlsx` — `## SheetName` per sheet; reads `.xlsm` too. No cell coordinates, so don't plan edits from it | | **Read** a model (formulas *and* values) | two `load_workbook` passes — see gotchas |
Best for
What’s inside
The SKILL.md for xlsx is organised into these sections:
- Requirements for every output
- Recalculate (mandatory whenever the file contains formulas)
- Choosing formulas that survive verification
- openpyxl gotchas
- Financial models
- Dependencies
Installation
Add xlsx to your agent with:
/plugin marketplace add anthropics/skillsReview a skill’s source before installing it — skills can instruct your agent to run commands. This command comes from the skill’s public repository, which is the source of truth for setup steps. New to skills? Read how to install Claude Code skills.
Supported agents
- Claude Code — ships a claude code plugin marketplace
License
anthropics has not declared a standard open-source license for this repository (Custom terms). Confirm the terms with the author before reusing it.
Strengths
- Ships in anthropics/skills, an established project with 177,416 GitHub stars
- Works with Claude Code
- Actively maintained — repository updated in the last 30 days
- Its repository gained 12,054 GitHub stars over the last 52 days
Things to check
- No license declared — confirm terms with the author before reuse
Author
Topics
Frequently asked questions
- What does xlsx do?
- Use this skill any time a spreadsheet file is the primary input or output. This means any task where the user wants to: open, read, edit, or fix an existing .xlsx, .xlsm, .xltx, .csv, or .tsv file (e.g., adding columns, computing formulas, formatting, charting, cleaning messy data); create a new spreadsheet from scratch or from other data sources; or convert between tabular file formats. Trigger especially when the user references a spreadsheet file by name or path — even casually (like "the xlsx in my downloads") — and wants something done to it or produced from it. Also trigger for cleaning or restructuring messy tabular data files (malformed rows, misplaced headers, junk data) into proper spreadsheets. The deliverable must be a spreadsheet file. Do NOT trigger when the primary deliverable is a Word document, HTML report, standalone Python script, database pipeline, or Google Sheets API integration, even if tabular data is involved.
- How do I install xlsx?
- Run /plugin marketplace add anthropics/skills in your agent, then reload your skills. Review the source at https://github.com/anthropics/skills before installing.
- Is xlsx free to use?
- xlsx is publicly available on GitHub, but anthropics has not declared a standard open-source license (Custom terms). Confirm the terms with the author before reusing it.
- Which agents does xlsx work with?
- xlsx lists Claude Code — named in its SKILL.md, its plugin marketplace or its repository topics. Skills use the portable SKILL.md format, so other agents that read that format may load it too.
- Where does xlsx come from?
- xlsx ships inside anthropics/skills, a repository that contains 21 catalogued skills in total. The repository's 177,416 GitHub stars apply to that whole collection, not to this skill on its own.
