# Excel Agent Workbench

> Analyze, clean, repair, transform, and create Microsoft Excel workbooks and spreadsheet files. Use when Codex needs to inspect or modify .xlsx, .xlsm, .xls, .csv, or .tsv files; build reports, dashboards, trackers, budgets, forecasts, financial models, charts, tables, validations, formulas, or workbook QA checks; convert sheets; audit formulas; detect hidden sheets/macros/external links; or produce professional Excel artifacts.

- Skill: `hieu-hm/excel-agent-workbench` (Agent Skill, multi-file: 7 files)
- Install (CLI): `npx skillmds@latest add hieu-hm/excel-agent-workbench`
- Raw SKILL.md: https://api.skillmd.com/api/skills/hieu-hm/excel-agent-workbench/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Data & Analytics
- Author: hieu-hm (https://skillmd.com/u/hieu-hm)
- Updated: 2026-09-22
- Page: https://skillmd.com/skills/hieu-hm/excel-agent-workbench

---


# Excel Agent Workbench

## Core Workflow

1. Clarify the target outcome from the prompt and attachments: read-only answer, workbook edit, new workbook, conversion, data cleanup, analysis, or dashboard/model build.
2. Profile existing files before changing them. Use `scripts/profile_workbook.py` for a compact workbook manifest when the file is `.xlsx` or `.xlsm`; use direct CSV/TSV inspection for plain text tables.
3. Preserve user data and existing workbook structure. Make the smallest reliable edit for targeted requests; create a new output file unless the user explicitly asks to overwrite.
4. Prefer formula-driven, auditable workbooks over hardcoded derived results. Put assumptions, sources, checks, and outputs in clear places.
5. Verify before finalizing: inspect key ranges, scan formulas/errors, and visually check important sheets when creating or editing presentation-quality files.

## Tool Selection

- Use the built-in `Spreadsheets` skill and `@oai/artifact-tool` when available for creating, editing, rendering, and exporting polished `.xlsx` artifacts. It provides workbook rendering and formula-aware inspection.
- Use bundled Python libraries for extraction, cleaning, profiling, and data analysis before workbook authoring. Prefer `pandas` for tabular transformations and `openpyxl` for workbook metadata or targeted `.xlsx/.xlsm` reads. Resolve the bundled Python path through workspace dependencies when system Python does not have these libraries.
- Use `scripts/profile_workbook.py` to summarize sheets, dimensions, formulas, tables, charts, merged cells, hidden sheets, defined names, external links, and VBA presence.
- Use `scripts/audit_workbook.py` to scan formulas and cells for common risks such as error values, external links, volatile functions, hidden sheets, very hidden sheets, macros, and formula-like text injection.
- Use `scripts/export_sheet_csv.py` when a single sheet must be converted to CSV for downstream processing or review.

## Workbook Design Standards

- Put a summary/dashboard first for analytical or executive outputs, followed by source data, assumptions, calculations, and checks.
- Use real Excel tables, filters, freeze panes, data validation, conditional formatting, and native charts when they improve usability.
- Keep inputs visually distinct from formulas and outputs. Common convention: editable inputs with a light fill, formulas with neutral formatting, checks with clear pass/fail styling.
- Avoid full-column formulas in models and dashboards. Use bounded ranges sized to the data or table references.
- Guard blank templates so formulas do not show noisy `#DIV/0!`, `#N/A`, or misleading rankings before data exists.
- Treat IDs, phone numbers, account numbers, postal codes, and long numeric strings as text to avoid leading-zero loss or Excel's 15-digit precision limit.
- Record source notes for externally sourced numbers: file/site name, date retrieved when relevant, and the exact table/section used.

## Editing Existing Workbooks

1. Create a backup or write a new output filename.
2. Profile the workbook and inspect the target ranges/sheets.
3. Preserve formulas, named ranges, conditional formatting, validations, filters, tables, and charts unless the request requires changing them.
4. If inserting rows/columns into structured areas, extend formulas, table ranges, conditional formats, validations, and charts consistently.
5. Do not execute macros. Preserve macros only when the user explicitly needs `.xlsm` output and the tool path supports safe preservation.

## Security And Data Hygiene

- Treat untrusted workbooks as hostile input. Do not run macros, Power Query refreshes, external data refreshes, or linked workbook updates.
- Scan for external links, hidden/very hidden sheets, suspicious formulas, and formula-like text in exported CSV/Excel data.
- Prevent CSV/Excel formula injection when writing untrusted text. Escape user-provided text that begins with `=`, `+`, `-`, `@`, tab, or carriage return unless it is intentionally a formula.
- Avoid exposing sensitive workbook data in chat. Summarize findings and reference ranges instead of dumping large tables.

## Verification Checklist

- Key outputs reconcile to source rows, assumptions, or formulas.
- Formula scan has no unexpected `#REF!`, `#DIV/0!`, `#VALUE!`, `#NAME?`, `#N/A`, or circular-reference symptoms.
- Workbook opens cleanly in Excel-compatible software or exports successfully via the chosen tooling.
- Important headers, values, charts, and notes are visible in rendered previews or screenshots.
- Final file path is clear and points to the generated workbook or converted output.

## References

- Read `references/formula-patterns.md` when building formula-heavy models or dashboards.
- Read `references/qa-checks.md` when auditing a workbook or preparing a file for business use.