Usage Rule

Use this skill when the format requirement is clearly spreadsheet / .xlsx / .csv / .tsv, whether stated explicitly or strongly implied by the deliverable.

Trigger it when the task clearly involves one of these goals:

Reading or modifying an existing spreadsheet file
Cleaning messy CSV/TSV/XLSX data into a proper spreadsheet
Adding formulas, formatting, charts, tabs, or derived columns inside a spreadsheet
Converting between spreadsheet-style file formats
Producing a spreadsheet file as the final deliverable

The user does not need to literally say .xlsx. If they clearly want a workbook, spreadsheet model, tabular handoff, or CSV/XLSX delivery rather than just a written analysis, this skill can be the right match.

Do not use this as the default for every data-related task.