scrub-pii

Scrub PII Before Public Publish

This skill runs before any public gist is created. For private gists it can be skipped (private gists are still on GitHub and indexable, but the bar is the user's call).

What to look for

Two passes — regex first (fast, catches the obvious), then a structured review pass (catches context-sensitive leaks).

Pass 1 — Regex

Flag every match. Don't auto-replace; surface them all and let the user decide per category.

Category	Patterns / examples
IPv4 (private/public)	\b(?:\d{1,3}\.){3}\d{1,3}\b — but ignore 0.0.0.0, 127.0.0.1, 255.255.255.0, common docs ranges (192.0.2.*, 198.51.100.*, 203.0.113.*)
IPv6	standard IPv6 patterns; ignore ::1
MAC	\b(?:[0-9A-Fa-f]{2}[:-]){5}[0-9A-Fa-f]{2}\b
Emails	[\w.+-]+@[\w-]+\.[\w.-]+
Hostnames (likely-private)	*.local, *.lan, *.home, *.internal, *.corp
Home-dir usernames	/home/<user>/, /Users/<user>/, /root/ (root is usually fine but flag for review)
API keys / tokens	sk-[A-Za-z0-9]{20,}, ghp_[A-Za-z0-9]{36}, github_pat_[A-Za-z0-9_]{82}, xox[baprs]-[A-Za-z0-9-]+ (Slack), AKIA[0-9A-Z]{16} (AWS), JWTs (eyJ[A-Za-z0-9_-]+\.eyJ[A-Za-z0-9_-]+\.[A-Za-z0-9_-]+), generic Bearer [A-Za-z0-9._-]+
Passwords / secrets in env-style lines	`(?i)(password
SSH private keys	`-----BEGIN (OPENSSH
AWS account IDs	\b\d{12}\b in AWS-context lines

Pass 2 — Structured review

After regex, re-read the document and look for:

• Hostnames that look custom (not in a public docs/RFC example set). E.g. cloudpi.local, ops-vps-01, prod-db-eu.
• Project / org names the user may not want public.
• Filesystem layouts that fingerprint the user's setup (e.g. ~/Documents/Clients/<RealClient>/).
• Internal URLs — anything not public.
• Commit hashes / branch names referencing private repos.
• Real names / handles other than the gist author's intended attribution.

Output

Produce a redaction report before the gist is created:

=== PII / Sensitive Data Scan ===

🔴 BLOCKING (must redact or abort):
  - SSH private key at line 42

🟡 LIKELY SENSITIVE (recommend redact):
  - IPv4 10.0.0.42 at line 17 (private RFC1918 → recommend `10.0.0.X`)
  - IPv4 91.123.45.67 at line 19 (public; could fingerprint host → recommend `<public-vps-ip>`)
  - Hostname `daniel-desktop.local` at line 23 → recommend `<workstation>.local`
  - Path `/home/daniel/repos/...` at line 31 → recommend `~/repos/...`

🟢 LOW RISK (review):
  - Email `public@example.com` at line 5 — looks intentional?

Apply redactions? [Y / select-categories / abort]

Redaction conventions

When the user accepts a redaction, replace with a clearly-marked placeholder, not deletion:

• IPs → <lan-ip> / <public-ip> / <vps-ip> (descriptive when possible)
• Hostnames → <workstation> / <server> / <host>.local
• Paths → collapse to ~/... for home dirs
• Tokens / keys → <REDACTED-TOKEN>
• Emails → <email> or keep if it's the public author email

Markers help future readers understand what kind of value belonged there.

When to abort

Abort and refuse to publish (don't just warn) if:

• An SSH private key, GPG private key, or .pem body is present.
• A live-looking API token is present and the user declines to redact.
• The user's git remote -v output for a private repo is embedded.

Standalone use

When invoked directly (not as a pre-flight), run the same two passes against a file or pasted content and produce the same report. Don't modify the source unless asked.