description: "Open, create, read, analyze, edit, or validate Excel/spreadsheet files (.xlsx, .xlsm, .csv, .tsv). Use when the user asks to create, build, modify, analyze, read, validate, or format any Excel spreadsheet, financial model, pivot table, or tabular data file. Covers: creating new xlsx from scratch, reading and analyzing existing files, editing existing xlsx with zero format loss, formula recalculation and validation, and applying professional financial formatting standards. Triggers on 'spreadsheet', 'Excel', '.xlsx', '.csv', 'pivot table', 'financial model', 'formula', or any request to produce tabular data in Excel format."
## READ — Analyze data (read `references/read-analyze.md` first)
Start with `xlsx_reader.py` for structure discovery, then pandas for custom analysis. Never modify the source file.
**Formatting rule**: When the user specifies decimal places (e.g. "2 decimal places"), apply that format to ALL numeric values — use `f'{v:.2f}'` on every number. Never output `12875` when `12875.00` is required.
**Aggregation rule**: Always compute sums/means/counts directly from the DataFrame column — e.g. `df['Revenue'].sum()`. Never re-derive column values before aggregation.
## CREATE — XML template (read `references/create.md` + `references/format.md`)
Copy `templates/minimal_xlsx/` → edit XML directly → pack with `xlsx_pack.py`. Every derived value MUST be an Excel formula (`<f>SUM(B2:B9)</f>`), never a hardcoded number. Apply font colors per `format.md`.
## EDIT — XML direct-edit (read `references/edit.md` first)
**CRITICAL — EDIT INTEGRITY RULES:**
1.**NEVER create a new `Workbook()`** for edit tasks. Always load the original file.
2. The output MUST contain the **same sheets** as the input (same names, same data).
3. Only modify the specific cells the task asks for — everything else must be untouched.
4.**After saving output.xlsx, verify it**: open with `xlsx_reader.py` or `pandas` and confirm the original sheet names and a sample of original data are present. If verification fails, you wrote the wrong file — fix it before delivering.
Never use openpyxl round-trip on existing files (corrupts VBA, pivots, sparklines). Instead: unpack → use helper scripts → repack.
**"Fill cells" / "Add formulas to existing cells" = EDIT task.** If the input file already exists and you are told to fill, update, or add formulas to specific cells, you MUST use the XML edit path. Never create a new `Workbook()`. Example — fill B3 with a cross-sheet SUM formula:
The `--border-row` flag applies a top border to ALL cells in that row (not just the new column). Use it when the task requires accounting-style borders on total rows.
**Insert a row** (shifts existing rows, updates SUM formulas, fixes circular refs):
**Row lookup rule**: When the task says "after row N (Label)", always find the row by searching for "Label" in the worksheet XML (`grep -n "Label" /tmp/xlsx_work/xl/worksheets/sheet*.xml` or check sharedStrings.xml). Use the actual row number + 1 for `--at`. Do NOT call `xlsx_shift_rows.py` separately — `xlsx_insert_row.py` calls it internally.
**Apply row-wide borders** (e.g. accounting line on a TOTAL row):
After running helper scripts, apply borders to ALL cells in the target row, not just newly added cells. In `xl/styles.xml`, append a new `<border>` with the desired style, then append a new `<xf>` in `<cellXfs>` that clones each cell's existing `<xf>` but sets the new `borderId`. Apply the new style index to every `<c>` in the row via the `s` attribute:
