Headless Excel Workbook Builder
Generate reviewable .xlsx artifacts in managed-agent sessions without an open Office application.
The skill restricts output to ./out/<name>.xlsx, requires no network, credentials, or external systems, and says not to append to an existing workbook; this provides some scope control. Points are deducted because user confirmation, sensitive-financial-data handling, overwrite/rollback controls, and pinned dependency requirements are absent.
The instructions and example are broadly consistent: use Python, Bash, and openpyxl to create and save a workbook, while directing users to Excel tools in Cowork mode. Points are deducted because dependency availability is not checked, abnormal inputs and save failures lack handling, and diagnostic failure feedback is unspecified; static review cannot support a score above 10.
The audience, output path, headless context, live-workbook boundary, and non-use condition are clearly stated. Points are deducted because input formats, failure boundaries, semantic trigger conditions, and Chinese-language support are unspecified, as is adaptation to mainland-China network conditions.
The document is clearly layered and includes an output contract, construction example, formatting conventions, and usage boundary; the repository supplies Apache-2.0 licensing, official Anthropic provenance, CI validation, and contribution guidance. Points are deducted because the skill itself lacks versioning, changelog, named maintenance responsibility, installation/dependency instructions, FAQ, detailed limitations, and an update path.
The skill directly addresses producing a collectable .xlsx artifact when no Office application is available, with a concrete minimal example and financial-model conventions. Points are deducted because it does not verify workbook output, formula behavior, or check-tab completeness; the example still requires human review, and comparative benefit over manual scripting or alternatives is not evidenced. Static calibration limits this to 7.
The repository includes real CI configurations for plugin validation and secret scanning, and the skill provides a concrete code pattern that is auditable. Points are deducted because there are no committed xlsx-author key-path tests, sample artifacts, third-party execution records, or corroborating sources; static calibration limits this to 5.
- Pin and verify Python and openpyxl versions before use because environment differences may reduce reproducibility.
- The skill does not prove that formulas calculate, balance checks pass, or the workbook matches a business template; human review is required before delivery.
- Overwrite behavior, partial files after failure, and recovery procedures for ./out/ are unspecified; callers must provide isolation, access control, and cleanup for sensitive financial data.
- Chinese text, locale-specific formats, dates, and formula localization are not addressed; Chinese users should validate compatibility first.
What it does & when to use it
xlsx-author creates Excel workbooks as files on disk instead of editing a live Excel workbook. It targets headless managed-agent or CMA sessions and requires output under ./out/<name>.xlsx. The skill specifies color conventions for hardcoded inputs, formulas, and links, along with Inputs, calculation, and Checks sheet practices. It fits workflows that need structured spreadsheet deliverables when no Office application is available.
Creates ./out/ when necessary, writes and runs a short Python script, uses openpyxl to create worksheets, cells, formulas, and styles, and saves the result as ./out/<name>.xlsx. It specifies blue for hardcoded inputs, black for formulas, and green for links to another sheet or file. Calculation cells must contain formulas rather than hardcoded values; inputs belong on an Inputs tab; and values referenced from a deck or memo should use named ranges. A Checks tab should surface balance-sheet, cash-flow, and related checks as TRUE/FALSE results.
- A managed-agent workflow needs to deliver a financial model as an Excel file without an open Office application.
- A financial analyst needs separate input, calculation, and validation areas in a generated workbook.
- A model builder needs visible color coding for hardcodes, formulas, and cross-sheet links.
- A reviewer needs workbook-level balance checks that clearly surface TRUE or FALSE.
- An orchestration pipeline needs to collect a generated .xlsx artifact from a known relative path.
Pros & cons
- Defines a precise, collectible output path for .xlsx artifacts.
- Supports fully headless workbook generation.
- Provides review-oriented conventions for inputs, formulas, links, named ranges, and checks.
- Uses the widely used Python openpyxl library.
- Requires Python, Bash, and openpyxl; the source does not specify versions.
- The source provides no test suite, error-handling design, or recovery workflow.
- It is a file-producing fallback; when mcp__office__excel_* tools are available, the skill directs users to use live-workbook operations instead.
- The source does not document testing coverage for complex formulas, external links, or Excel compatibility.
How to install
Add the repository in Claude Cowork through Settings → Plugins → Add plugin, then paste https://github.com/anthropics/financial-services and select the relevant plugin; or in Claude Code run: claude plugin marketplace add anthropics/financial-services. The README does not provide a separate installation command for xlsx-author. The skill is located at plugins/agent-plugins/statement-auditor/skills/xlsx-author/SKILL.md.
How to use
In a headless, managed-agent, or CMA session, request an Excel file, for example: “Create an .xlsx financial model with Inputs, calculation, and Checks sheets, and save it as ./out/model.xlsx.” The SKILL.md does not define a formal trigger syntax or input schema. The final response should return the relative path ./out/<name>.xlsx.
Compared to similar skills
The SKILL.md distinguishes xlsx-author from mcp__office__excel_* live workbook operations: xlsx-author is for headless file generation, while those tools are intended for live workbook editing in Cowork plugin mode.