What problem does it solve? Spreadsheet tasks often fail silently: formulas written by openpyxl have no cached values, unsupported functions become #NAME? errors, and external workbook links get destroyed on save. This Skill provides a verified workflow for producing spreadsheet files with zero formula errors and correct, recalculated values. ## Core Features & Use Cases - Spreadsheet creation and editing: Build or modify .xlsx, .xlsm, .xltx, .csv, and .tsv files with openpyxl and pandas, following financial-modeling conventions for colors, number formats, and structure. - Mandatory formula recalculation: The recalc.py script runs LibreOffice headless to compute every formula, rewrites the file in place, and reports JSON error summaries naming exact cells with #VALUE!, #REF!, #NAME?, and other errors. - External-link protection: Detects formulas referencing other workbooks whose cached values would be lost on recalculation and refuses to run unless forced. - Use Case: A user asks to add a revenue projection tab to an existing financial model. The Skill writes formulas with openpyxl, runs recalc.py to verify zero errors, and delivers a workbook whose values are correct and recalculate when inputs change. ## Quick Start Use the xlsx skill to add a SUM formula column to my sales-data.xlsx file and verify it recalculates without errors.
