XLSX Author
OfficialFreeGenerate Excel files in headless mode without Excel app.
Free · Opens the source repo
What XLSX Author does
The XLSX Author skill allows developers and data analysts to create Excel workbooks programmatically without requiring an open instance of Microsoft Excel. This is particularly useful in headless environments or managed-agent sessions where traditional Excel operations are not feasible. By utilizing this skill, users can automate the generation of .xlsx files directly on disk, ensuring that their workflows remain efficient and streamlined.
To create an Excel workbook, users write a short Python script that leverages the openpyxl library. This script can define input values, formulas, and formatting styles, enabling the creation of complex financial models or data reports. The output is saved as a .xlsx file in a specified directory, allowing easy access and integration into larger systems. The skill adheres to conventions that promote best practices in Excel file creation, such as using dedicated input sheets and ensuring all calculations are formula-driven.
This skill is ideal for situations where automated reporting or data processing is required without manual intervention. It is particularly suited for developers who need to generate Excel files as part of a data pipeline or automated analysis process. By following the established conventions, users can ensure that their Excel files are not only functional but also maintain a clear structure that facilitates further analysis or review.
However, it is important to note that this skill should not be used in scenarios where the mcp__office__excel_* tools are available. These tools provide a more interactive experience by allowing users to edit live workbooks, which is not possible with the XLSX Author skill.
When to use it
Use this skill in headless environments or managed-agent sessions where Excel cannot be run.
When not to use it
Avoid using this skill when you have access to `mcp__office__excel_*` tools that allow direct interaction with live Excel workbooks.
What you can build with it
Automated Financial Reporting
Generate financial models and reports automatically without needing to open Excel, streamlining the reporting process.
Batch Processing of Data
Create multiple Excel files in a batch process for data analysis or export, improving efficiency in data handling.
Integration with Data Pipelines
Incorporate Excel file generation into data pipelines where headless execution is required, ensuring seamless automation.
How to install XLSX Author
View source1. Install with the skills CLI
npx skills add anthropics/financial-services/xlsx-author --agent claude-code2. Or install it manually
Download the skill folder and drop it into ~/.claude/skills/ for all projects, or .claude/skills/ to scope it to one repo. Restart Claude Code so it picks up the new skill.
Anthropic's agentic coding CLI, and the reference implementation of Agent Skills. Drop a skill folder into ~/.claude/skills and Claude Code loads it automatically whenever a task matches the skill's description. Claude Code docs
Inside SKILL.md
Written by anthropicsxlsx-author
Use this skill when running headless (managed-agent / CMA mode) and you need to deliver an Excel workbook as a file artifact rather than editing a live workbook via mcp__office__excel_*.
Output contract
- Write to
./out/<name>.xlsx. Create./out/if it does not exist. - Return the relative path in your final message so the orchestration layer can collect it.
How to build the workbook
Write a short Python script and run it with Bash. Use openpyxl:
from openpyxl import Workbook
from openpyxl.styles import Font, PatternFill
wb = Workbook()
ws = wb.active; ws.title = "Inputs"
ws["B2"] = "Revenue"; ws["C2"] = 1_250_000_000
ws["C2"].font = Font(color="0000FF") # blue = hardcoded input
calc = wb.create_sheet("DCF")
calc["C5"] = "=Inputs!C2*(1+Inputs!C3)" # black = formula
wb.save("./out/model.xlsx")
Conventions (mirror audit-xls)
- Blue / black / green. Blue = hardcoded input, black = formula, green = link to another sheet/file.
- No hardcodes in calc cells. Every calculation cell is a formula; every input lives on an Inputs tab.
- Named ranges for any value referenced from a deck or memo.
- Balance checks. Include a Checks tab that ties (BS balances, CF ties to cash, etc.) and surfaces TRUE/FALSE.
- One model per file. Do not append to an existing workbook unless explicitly asked.
When NOT to use
If mcp__office__excel_* tools are available (Cowork plugin mode), use those instead — they drive the user's live workbook with review checkpoints. This skill is the file-producing fallback for headless runs.
Frequently asked questions about XLSX Author
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