XLSX

Why you would use it

XLSX is for XLSX read/write workflows, spreadsheet cleanup, and data export. Read, organize, and generate XLSX files for spreadsheet-heavy tasks.

You would use it when the task is already clear, but you do not want to design the workflow, prompt structure, or tool wiring from scratch. A good skill gives you a pre-shaped execution path and cuts down trial and error.

The practical check is simple: does the task match, does the output match, and does your current stack fit the implementation style used in Anthropic. If those line up, the source folder is worth opening.