Xlsx Author

When you're running Claude in headless mode and need to produce an Excel file as an artifact rather than editing a live workbook, this skill drops a Python script that uses openpyxl to generate the .xlsx in an ./out directory. It follows the same conventions as audit-xls: blue for hardcoded inputs, black for formulas, green for links, with everything structured around an Inputs tab and a Checks tab for balance ties. The documentation is clear about when not to use it, which is helpful. If the mcp__office__excel tools are available in Cowork plugin mode, use those instead since they let users review changes in real time. This is the file producing fallback for managed agent sessions.