Delv
Anthropic★ 4.3

Excel

Create, read, and modify Excel spreadsheets. Claude writes the formulas, sheets, and formatting - you get a working xlsx file out.

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A+
Safety & Trust

Delv Safety Grade: A+

Score 93/100 · assessed 2026-04-18

Maintainer95
Permissions92
Supply chain90
Transparency92
Incidents100

Official Anthropic skill for Excel file generation, maintained in the first-party skills repository. The skill creates, reads, and modifies .xlsx files with formulas, formatting, and multiple sheets. Permissions are well-scoped to filesystem operations for Excel files only, with no network access, shell execution, or credential handling. The skill operates locally, writing files to the user's filesystem without external API calls. Supply chain is clean: distributed through Anthropic's official repository with clear versioning and standard Python dependencies (openpyxl). Documentation is thorough with examples and clear capability boundaries. No known security incidents. The main consideration is filesystem write access, which is inherent to the skill's purpose and appropriately scoped to .xlsx file creation rather than arbitrary filesystem manipulation.

Green flags

  • Official Anthropic skill, first-party maintenance
  • No network access or external API calls required
  • Well-documented with clear examples in official repo
  • Uses standard openpyxl library, widely vetted
  • Scoped to Excel file operations only, no shell access

Red flags

  • Filesystem write permission required for .xlsx output
  • Could overwrite existing Excel files if paths conflict
  • Formulas in generated files execute when opened in Excel

Permissions requested

Read filesWrite files
Assessed by Delv Editorial using public metadata. Grades are advisory and update as the ecosystem changes. They do not replace your own review of permissions and code before granting an agent access to sensitive systems.

The Excel Skill teaches Claude to generate proper .xlsx files with formulas, formatting, and multiple sheets. Instead of exporting raw data or CSV tables, you get a working spreadsheet you can open in Excel or Google Sheets. It handles financial models, weekly reports, and data exports for non-technical stakeholders. Claude writes the formulas, labels the columns, formats currency and percentages, and structures multi-sheet workbooks. It can also read uploaded .xlsx files for analysis, though it doesn't sync live files from your filesystem. Useful for automating repetitive spreadsheet tasks or turning conversational requirements into working templates. It won't replace Excel for advanced features like pivot tables, macros, or VBA, but it removes the manual formatting step for common jobs.

Review

Before this Skill, asking Claude to generate an Excel file meant getting CSV data or a table you'd paste into a blank workbook yourself. The Excel Skill changes that: Claude now writes actual .xlsx files with formulas, formatting, multiple sheets, and structure you can open straight in Excel or Google Sheets. I've used it for two jobs where it genuinely saves time. First, building financial models from conversation. You describe a three-statement model or a scenario analysis, and Claude writes the formulas, labels the rows, formats currency cells, and links the sheets. You still check the logic, but you're not typing SUM() functions or aligning columns. Second, exporting data for non-technical stakeholders. If you've got JSON or a dataset Claude's already processed, the Skill formats it into a readable spreadsheet with headers, filters, and conditional formatting where it makes sense. The difference from doing this manually is speed and fewer formatting errors. Without the Skill, you'd either export raw data and tidy it yourself, or spend ten minutes explaining to Claude how to structure a CSV that Excel won't mangle. With the Skill, you get a working file in one prompt. Rough edges: Claude sometimes overformats. You might get bold headers and colour-coded cells when a plain table would do. It also can't handle truly complex Excel features like pivot tables, macros, or advanced charting. If your model needs VBA or intricate conditional logic, you're still building it by hand. And because it's a Skill, not an MCP, Claude can't read live Excel files from your filesystem. You upload an .xlsx, Claude parses it, but there's no two-way sync. For weekly reports, budget templates, or quick financial models, it's useful. For anything that needs Excel's full feature set, it's a starting point, not a replacement.
Verdict

Load this if you regularly turn Claude's output into spreadsheets for others, or if you build simple financial models and want Claude to write the formulas. Skip it if you need pivot tables, macros, or live file editing.

Good at

  • Generates actual .xlsx files, not just CSV data
  • Writes formulas and links sheets correctly for financial models
  • Formats currency, percentages, and headers without manual cleanup
  • Reads uploaded Excel files for analysis or modification
  • Saves time on weekly reports and template generation

Watch out

  • No support for pivot tables, macros, or VBA
  • Sometimes overformats when a plain table would suffice
  • Can't read or sync live files from your filesystem
  • Limited to simpler Excel features, not enterprise-grade models
  • Requires manual review of formula logic for critical work

Use cases

  • Building financial models from a conversation
  • Exporting data to Excel for non-technical stakeholders
  • Reading historical xlsx files for analysis
  • Automating weekly reporting sheets