analyzing-spreadsheets
Processes Excel spreadsheet files (.xlsx, .xlsm, .csv). Creates workbooks, builds formulas, preserves formatting, analyzes tabular data, and validates financial models with zero-formula-error delivery. Use when working with spreadsheet files or tabular data analysis. Do NOT use for Word documents, PDFs, presentations, or database pipelines.
SKILL.md
Full skill instructions
XLSX Processing
Create, edit, analyze .xlsx files. LibreOffice required for formula recalculation via recalc.py.
Iron Rule
Zero formula errors at delivery. All formulas must compute — no #REF!, #DIV/0!, #VALUE!, #N/A, #NAME?. Always run recalc.py after writing formulas.
Decision Matrix
| Task | Tool | Reference |
|---|---|---|
| Data analysis, bulk ops, simple export | pandas | recipes.md |
| Formulas, formatting, Excel features | openpyxl | recipes.md |
| Financial model standards | — | financial-model.md |
| Recalculate formulas | recalc.py | recipes.md |
Common Workflow
- Choose tool: pandas for data, openpyxl for formulas/formatting
- Create/Load workbook
- Modify data, formulas, formatting
- Save
- Recalculate (MANDATORY if formulas):
python recalc.py output.xlsx - Verify & fix errors — check JSON output, fix
#REF!/#DIV/0!/#VALUE!/#NAME?
Hard Constraints
- Use formulas, not hardcoded values — calculations stay dynamic. See recipes.md.
- Preserve existing templates — match existing format/style EXACTLY when updating; user template overrides defaults.
- Financial models — follow color/format conventions in financial-model.md.
Code Style
- Concise Python, no unnecessary comments or print statements.
- Excel files: comment cells with complex formulas, document hardcode sources.