Excel Hygiene — Development skill for Claude Code

excel-hygiene

A rigorous **"second pair of eyes"** on any `.xlsx` before it goes out — packaged as a [Claude Code / Agent Skills](https://agentskills.io) skill.

It combines two layers:

1. A deterministic Python script (scripts/check_excel.py, openpyxl-only) for precise, reproducible mechanical checks.
2. LLM reasoning driven by the full Panko–Halverson (2008) spreadsheet-error taxonomy embedded in SKILL.md — violations vs errors · qualitative vs quantitative · mistakes / slips / lapses · life-cycle stages — applied with general business and spreadsheet knowledge.

The script is a **floor, not a ceiling**: the skill explicitly tells the agent to reason *beyond* the listed checks, never to treat them as a fixed checklist. It is client-agnostic — no business rules are baked in.

What the script catches (mechanical, high-confidence)

Check	What it flags
Number as text	A numeric value stored as a string → SUM silently skips it, the total is understated
Number over formula	A static number sitting in a column that is otherwise formulas → a formula may have been overwritten
Cell error	#DIV/0! / #REF! / … literals (EN and RU), and formulas that divide by zero
Truncated SUM	A vertical SUM that stops before the last populated data row → a row may be dropped
Percent as whole number	A value > 1 in a column whose header contains % → likely off by ×100

Everything else — logic errors, omissions, ambiguous units, structural smells — is surfaced by the agent's reasoning against the taxonomy, and marked **"confirm"** (lower confidence than the script).

Install

This is a personal/project skill — just drop the folder where Claude Code looks for skills.

**Personal (all projects):**

git clone https://github.com/BayramAnnakov/excel-hygiene ~/.claude/skills/excel-hygiene
pip install -r ~/.claude/skills/excel-hygiene/requirements.txt

**Project-scoped (this repo only):** ```bas