excel

excel is a skill for Claude Code from Rockielab/rockie-claude. It costs 26 tokens per session (1,045 once invoked), scanned A, original, Apache-2.0.

A tool for creating, changing, analysing, and validating Excel .xlsx workbooks, including formulas and formatting.

In plain words
What is it for?
Use it to build or inspect real Excel workbooks and export validated spreadsheet artifacts.
Why use it?
It helps produce checked spreadsheet files while protecting against unsafe formula-like input.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the rockie-claude plugin — 29 skills, 1 MCP server shipped together

Good fit Use it to build or inspect real Excel workbooks and export validated spreadsheet artifacts.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/rockielab/rockie-claude/excel
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add Rockielab/rockie-claude --skill excel
Clone the repo
git clone --depth 1 https://github.com/Rockielab/rockie-claude

Made for: Claude Code.

Or install rockie-claude, the plugin that ships this one along with the rest of its 29 skills, 1 MCP server.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for excel

README.md
[![agentmods](https://agentmods.dev/badge/skills/rockielab/rockie-claude/excel/github.svg)](https://agentmods.dev/skills/rockielab/rockie-claude/excel)
Your own site
<a href="https://agentmods.dev/skills/rockielab/rockie-claude/excel"><img src="https://agentmods.dev/badge/skills/rockielab/rockie-claude/excel/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for excel

Your own site · 80×15
<a href="https://agentmods.dev/skills/rockielab/rockie-claude/excel"><img src="https://agentmods.dev/badge/skills/rockielab/rockie-claude/excel.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 26 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,045 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00026 $0.01045
Opus 5 $0.00013 $0.00522
Sonnet 5 $0.00005 $0.00209
Haiku 4.5 $0.00003 $0.00104

Measured 10d ago against content hash bb1456f51b38, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

excel scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 10d ago.

The scan reads SKILL.md. This mod also ships 2 executable files (runtime/renderer.py, runtime/sanitize.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

  • excel — 100% identical, 0 lines differ
project-harness/skills/excel/SKILL.md · 133 lines

How it starts

The opening of the file, as written. The whole thing — 133 lines — stays where its author put it; the contents beside it link to each section on GitHub.

excel

Use this skill when the user asks for an Excel workbook or an .xlsx artifact, including creating, modifying, formatting, analyzing, validating, or exporting workbook content. For read-only analysis or validation requests, inspect the workbook and report findings without writing a new file unless the user asks for one.

In tenant runtimes, new workbook generation is productized through skills/excel/runtime/renderer.py. Generate the workbook locally in the tenant workspace, verify it, then publish it with the emit_artifact tool using:

  • kind: "spreadsheet"
  • content_encoding: "base64"
  • filename: "<safe-name>.xlsx"
  • mime_type: "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
  • destinations: ["ui", "chat"]

Core rules

  • Produce a real .xlsx workbook. Do not rename CSV, TSV, HTML, JSON, or plain text files to .xlsx.
  • Use runtime/sanitize.py at the cell-write boundary. Strings starting with =, +, -, or @ are text unless the cell is explicitly typed as a formula.
  • Preserve source data. Keep raw inputs available when appropriate, such as a Source Data or Raw Data sheet, and avoid silently replacing user-provided values with summaries.
  • Use workbook features that fit the task: multiple sheets, formulas, number formats, styles, column widths, freeze panes, filters, charts, data validation, named ranges, and notes/comments when they materially improve usability.
  • Keep formulas as formulas unless the user explicitly asks for static values.
  • When writing a workbook, reopen and verify the finished file before reporting it.
  • When writing a workbook, report the emitted artifact id or final path.
  • Cap new workbook generation at 20 sheets. If the user asks for more, create the most useful 20 or fail clearly before writing, depending on the task.

Verification

After writing the .xlsx, reopen it with an Excel-capable parser or by inspecting the ZIP/XML package when no dependency is available. Verify:

Read the full file on GitHub · 133 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 10d ago First seen · 133 lines · 26 tokens per session scan A bb1456f51b38

Subscribe to this mod's changes

excel is a skill published in the GitHub repository Rockielab/rockie-claude (21 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 26 tokens to every session and 1,045 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.