1. Confirm the file type and goal: create, edit, analyze, or visualize.
2. Prefer `openpyxl` for `.xlsx` editing and formatting. Use `pandas` for analysis and CSV/TSV workflows.
3. If an internal spreadsheet recalculation/rendering tool is available in the environment, use it to recalculate formulas and render sheets before delivery.
4. Use formulas for derived values instead of hardcoding results.
5. If layout matters, render for visual review and inspect the output.
6. Save outputs, keep filenames stable, and clean up intermediate files.