| name | Excel / XLSX |
| slug | excel-xlsx |
| version | 1.0.2 |
| homepage | https://clawic.com/skills/excel-xlsx |
| description | Create, inspect, and edit Microsoft Excel workbooks and XLSX files with reliable formulas, dates, types, formatting, recalculation, and template preservation. Use when (1) the task is about Excel, `.xlsx`, `.xlsm`, `.xls`, `.csv`, or `.tsv`; (2) formulas, formatting, workbook structure, or compatibility matter; (3) the file must stay reliable after edits. |
| whenToUse | User needs to create, edit, or analyze Excel/XLSX spreadsheet files |
| changelog | Tightened formula anchoring, recalculation, and model traceability after a stricter external spreadsheet audit. |
| metadata | {"clawdbot":{"emoji":"📗","requires":{"bins":[]},"os":["linux","darwin","win32"]}} |
When to Use
Use when the main artifact is a Microsoft Excel workbook or spreadsheet file, especially when formulas, dates, formatting, merged cells, workbook structure, or cross-platform behavior matter.
Core Rules
1. Choose the workflow by job, not by habit
- Use
pandas for analysis, reshaping, and CSV-like tasks.
- Use
openpyxl when formulas, styles, sheets, comments, merged cells, or workbook preservation matter.
- Treat CSV as plain data exchange, not as an Excel feature-complete format.
- Reading values, preserving a live workbook, and building a model from scratch are different spreadsheet jobs.
2. Dates are serial numbers with legacy quirks
- Excel stores dates as serial numbers, not real date objects.
- The 1900 date system includes the false leap-day bug, and some workbooks use the 1904 system.
- Time is fractional day data, so formatting and conversion both matter.
- Date correctness is not enough if the number format still displays the wrong thing to the user.
3. Keep calculations in Excel when the workbook should stay live
- Write formulas into cells instead of hardcoding derived results from Python.
- Use references to assumption cells instead of magic numbers inside formulas.
- Cached formula values can be stale, so do not trust them blindly after edits.
- Check copied formulas for wrong ranges, wrong sheets, and silent off-by-one drift before delivery.
- Absolute and relative references are part of the logic, so copied formulas can be wrong even when they still "work".
- Test new formulas on a few representative cells before filling them across a whole block.
- Verify denominators, named ranges, and precedent cells before shipping formulas that depend on them.
- A workbook should ship with zero formula errors, not with known
#REF!, #DIV/0!, #VALUE!, #NAME?, or circular-reference fallout left for the user to fix.
- For model-style work, document non-obvious hardcodes, assumptions, or source inputs in comments or nearby notes.
4. Protect data types before Excel mangles them
- Long identifiers, phone numbers, ZIP codes, and leading-zero values should usually be stored as text.
- Excel silently truncates numeric precision past 15 digits.
- Mixed text-number columns need explicit handling on read and on write.
- Scientific notation, auto-parsed dates, and stripped leading zeros are common corruption, not cosmetic issues.
