xlsx

xlsx is a skill for Claude Code, Codex from mateaix/mateclaw. It costs 93 tokens per session (1,587 once invoked), scanned A, original, Apache-2.0.

A set of rules for working with spreadsheet files such as Excel workbooks, CSV files, and TSV files. It covers how to create or edit them and how their formatting and formulas should be checked.

In plain words
What is it for?
Use it when reading, creating, converting, editing, or repairing spreadsheet data, including financial models and other tabular files.
Why use it?
It helps prevent broken formulas, inconsistent formatting, and accidental changes to an existing spreadsheet template.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it when reading, creating, converting, editing, or repairing spreadsheet data, including financial models and other tabular files.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/mateaix/mateclaw/xlsx
About the project

MateClaw is a pluggable agent runtime that coordinates AI agents, tools, conversations, memory, and workflows. It is designed for personal and multi-user AI assistants, including agents used through chat platforms. Catalogue add-ons provide skills for extending its agent workflows.

mateaix/mateclaw · 1,170 stars · on GitHub · claw.mate.vip

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 mateaix/mateclaw --skill xlsx
Clone the repo
git clone --depth 1 https://github.com/mateaix/mateclaw

Made for: Claude Code, Codex.

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 xlsx

README.md
[![agentmods](https://agentmods.dev/badge/skills/mateaix/mateclaw/xlsx/github.svg)](https://agentmods.dev/skills/mateaix/mateclaw/xlsx)
Your own site
<a href="https://agentmods.dev/skills/mateaix/mateclaw/xlsx"><img src="https://agentmods.dev/badge/skills/mateaix/mateclaw/xlsx/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 xlsx

Your own site · 80×15
<a href="https://agentmods.dev/skills/mateaix/mateclaw/xlsx"><img src="https://agentmods.dev/badge/skills/mateaix/mateclaw/xlsx.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 93 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,587 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. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Prompt Injection · line 68
    Subtle instructions detected that may alter agent decision-making or introduce hidden biases.
    Fix: Review content for implicit steering or bias. Ensure instructions are explicit and align with the skill's stated purpose.
How audits are shown
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 $0.00093 $0.01587
Opus 5.5 $0.00037 $0.00635
Sonnet 5.5 $0.00019 $0.00317
Haiku 4.5 $0.00009 $0.00159

Measured 1mo ago against content hash 43eb2c678e24, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

xlsx 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 1mo ago.

The scan reads SKILL.md. This mod also ships 13 executable files (scripts/office/helpers/__init__.py, scripts/office/helpers/merge_runs.py, scripts/office/helpers/simplify_redlines.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.

mateclaw-server/src/main/resources/skills/xlsx/SKILL.md · 214 lines

How it starts

The opening of the file, as written. The whole thing — 214 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Important: All scripts/ paths are relative to this skill directory. Use run_skill_script tool to execute scripts, or run with: cd {this_skill_dir} && python scripts/...

Requirements for Outputs

All Excel files

Professional Font

  • Use a consistent, professional font (e.g., Arial, Times New Roman) unless otherwise instructed

Zero Formula Errors

  • Every Excel model MUST be delivered with ZERO formula errors (#REF!, #DIV/0!, #VALUE!, #N/A, #NAME?)

Preserve Existing Templates

  • Study and EXACTLY match existing format, style, and conventions when modifying files
  • Existing template conventions ALWAYS override these guidelines

Financial Models

Color Coding Standards

  • Blue text (0,0,255): Hardcoded inputs
  • Black text (0,0,0): ALL formulas and calculations
  • Green text (0,128,0): Links from other worksheets
  • Red text (255,0,0): External links to other files
  • Yellow background (255,255,0): Key assumptions needing attention

Number Formatting Standards

  • Years: Format as text strings ("2024" not "2,024")
  • Currency: Use $#,##0 format; specify units in headers ("Revenue ($mm)")
  • Zeros: Format as "-" including percentages
  • Percentages: Default to 0.0% format
  • Multiples: Format as 0.0x
  • Negative numbers: Use parentheses (123) not minus -123

Formula Construction Rules

  • Place ALL assumptions in separate assumption cells
  • Use cell references instead of hardcoded values
  • Example: Use =B5*(1+$B$6) instead of =B5*1.05

XLSX creation, editing, and analysis

Prerequisites

  • openpyxl: Excel file creation and editing
  • pandas: data analysis and bulk operations
  • LibreOffice (soffice): formula recalculation via scripts/recalc.py

CRITICAL: Use Formulas, Not Hardcoded Values

Always use Excel formulas instead of calculating values in Python and hardcoding them.

WRONG - Hardcoding

total = df['Sales'].sum()
sheet['B10'] = total  # Bad: hardcodes 5000

Read the full file on GitHub · 214 lines

Files

What ships with it

53 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. 1mo ago First seen · 214 lines · 93 tokens per session scan A 43eb2c678e24

Subscribe to this mod's changes

xlsx is a skill published in the GitHub repository mateaix/mateclaw (1,170 stars, last pushed 2d ago), licensed Apache-2.0. It adds 93 tokens to every session and 1,587 once invoked, about $0.0004 per session on Opus 5.5. 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.

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