# XLSX Tools

> Professional Excel tools for creating, reading, and manipulating .xlsx spreadsheets. Build new workbooks with full styling and formula control, extract data as Markdown or JSON, recalculate formulas, and convert between formats (CSV, PDF, ODS).



Tags: Spreadsheets, XLSX, Excel, Data Analysis


## Example Prompts

- Create an Excel spreadsheet with financial projections and formulas
- Extract data from an XLSX file as Markdown tables
- Build a formatted Excel report with charts-ready data and conditional formatting
- Convert a CSV file to a styled XLSX workbook
- Recalculate all formulas in a spreadsheet and check for errors

URL: https://rakenne.app/skills/xlsx-tools/index.md

Try this skill: https://rakenne.app/a/?skill=xlsx-tools


## Overview

Professional Excel tools for creating, reading, and manipulating .xlsx spreadsheets.

With this skill you can:

- Create new .xlsx workbooks with full control over formatting, formulas, and data layout
- Read and extract data from existing Excel files as Markdown tables or JSON
- Modify existing spreadsheets by loading, editing, and saving them back
- Recalculate all formulas and scan for errors (#REF!, #VALUE!, #DIV/0!)
- Convert between spreadsheet formats such as CSV, XLSX, PDF, ODS, and HTML

## Getting Started

Add your source data or existing spreadsheets to the project workspace, then activate the *XLSX Tools* skill. The agent will guide you through the process step by step.

### Typical workflows

- **Build a financial model**: Ask the agent to create a multi-sheet workbook with assumptions, calculations, and a summary dashboard. The agent uses `xlsx_build` with ExcelJS to produce a professionally styled .xlsx that opens cleanly in Excel.
- **Extract data for analysis**: When you need to inspect or process spreadsheet contents, the agent can use `xlsx_extract_data` to return the data as readable Markdown tables or structured JSON arrays.
- **Modify an existing spreadsheet**: The agent can load an existing .xlsx file with `xlsx_build` (using `inputPath`), update specific cells, add formulas, apply formatting, and save the result to a new file.
- **Verify formulas**: After building a formula-heavy spreadsheet, ask the agent to run `xlsx_recalc` to force evaluation of all formulas and check for error values.
- **Convert formats**: Use `xlsx_convert` to move between CSV, XLSX, PDF, ODS, and HTML while preserving as much structure as possible.

## Tool Reference

The XLSX Tools skill exposes four specialized tools. You do not need to remember their names—the agent will choose the right one—but this reference explains what is available.

### Create and modify spreadsheets

- **`xlsx_build`**: Programmatically creates new .xlsx files or modifies existing ones using the ExcelJS JavaScript library. Best for generating structured spreadsheets (financial models, reports, data exports) with precise control over formulas, styling, number formats, and layout. When an `inputPath` is provided, the existing file is pre-loaded so you can modify specific cells or sheets.

### Read spreadsheet data

- **`xlsx_extract_data`**: Reads an .xlsx file and returns its contents as either:
  - Markdown tables (human-readable, one table per sheet)
  - JSON arrays (programmatic access, one array of rows per sheet)

  You can filter to specific sheets by name if you only need a subset of the data.

### Verify formulas

- **`xlsx_recalc`**: Recalculates all formulas in an .xlsx file using LibreOffice headless, then scans the result for error values. ExcelJS stores formulas as text without evaluating them—this tool forces a full evaluation pass to catch issues like #REF!, #VALUE!, and #DIV/0!.

### Format conversion

- **`xlsx_convert`**: Uses LibreOffice in headless mode to convert spreadsheets between formats, such as:
  - `.csv` → `.xlsx`
  - `.xlsx` → `csv`
  - `.xlsx` → `pdf`
  - `.xlsx` → `ods`
  - `.ods` → `.xlsx`

## Best Practices

- **Never overwrite the original file**: The agent always writes to a new path (for example, `_updated`, `_final`, `_report`) so you can compare and revert.
- **Use formulas over hardcoded values**: Financial models should be formula-driven so assumptions can be changed without reworking the whole spreadsheet.
- **Recalculate before sharing**: For important deliverables, ask the agent to run `xlsx_recalc` to verify all formulas compute correctly.
- **Reference the API docs**: The agent has access to a full ExcelJS API reference covering workbooks, worksheets, cells, formulas, styling, number formats, merging, conditional formatting, data validation, images, and print setup.


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