Sanitise Ascii

ASCII Sanitise Skill

Ensures Markdown and SKILL.md files contain only ASCII characters before they are committed or shared. Auto-fixes known typographic characters; flags anything it cannot fix.

Tools

Two deliverables live in the repo root (or ~/.git-hooks/ for global use):

Running manually

The script requires Python. Use whichever invocation works in your environment:

# Fix a specific file
./sanitise-ascii.py path/to/SKILL.md        # if executable bit is set
python3 sanitise-ascii.py path/to/SKILL.md  # explicit python3
python sanitise-ascii.py path/to/SKILL.md   # on systems where python = python3

# Fix all .md files under a directory
./sanitise-ascii.py --dir ./skills

# Check only (no writes) -- exits 1 if non-ASCII found
./sanitise-ascii.py --check path/to/SKILL.md

# Allow emoji (checkmarks, crosses) through without flagging
./sanitise-ascii.py --allow-emoji path/to/SKILL.md

The script has a #!/usr/bin/env python3 shebang, so chmod +x sanitise-ascii.py and running it directly is the most portable option.

Installing the pre-commit hook

Single repo

cp .githooks/pre-commit-sanitise-ascii /path/to/repo/.git/hooks/
chmod +x /path/to/repo/.git/hooks/pre-commit-sanitise-ascii
cp scripts/sanitise-ascii.py /path/to/repo/sanitise-ascii.py

All repos (global)

mkdir -p ~/.githooks
cp .githooks/pre-commit-sanitise-ascii ~/.githooks/
chmod +x ~/.githooks/pre-commit-sanitise-ascii
git config --global core.hooksPath ~/.githooks

# Put the script somewhere on PATH, e.g.:
cp scripts/sanitise-ascii.py /usr/local/bin/sanitise-ascii.py

The hook finds sanitise-ascii.py by looking in:

1. Repo root
2. Hooks directory
3. PATH

If it cannot find the script it warns and allows the commit through (non-blocking degradation).

What gets fixed automatically

See REPLACEMENTS dict in sanitise-ascii.py for the full map.

What is NOT auto-fixed

• Characters not in the replacement map
• Emoji (✅ ❌) -- flagged unless --allow-emoji is passed
• Actual language characters (accented letters etc.) -- these are flagged as WARNs and block the commit until resolved manually

Mojibake note

This can be tricky. The â character (and similar) is not itself a problem -- it is a symptom of UTF-8 content being read as Latin-1. The root cause is the source character (e.g. an en dash, U+2013, encoded as 0xE2 0x80 0x93 in UTF-8). Fixing the source character eliminates the mojibake wherever it appears downstream.

Adding to CI

# GitHub Actions example
- name: Check ASCII cleanliness
  run: ./sanitise-ascii.py --check --dir ./skills

Extending the fix map

Edit REPLACEMENTS in sanitise-ascii.py. Each entry is:

"\uXXXX": "ascii-equivalent",

Run python3 sanitise-ascii.py --check <file> to discover new offenders -- it prints the Unicode codepoint and surrounding context for each unfixed character.