AI Guardienne
A Chrome Manifest V3 extension that scans pasted, typed, and submitted text for secrets, PII, PCI, and PHI — entirely on-device, zero network calls. V1 loads unpacked; Web Store publication is Coming Soon.
Build & install
# Node 20+ required cd backend/radar_scanner/products/ai_shield npm install npm run build # chrome://extensions → Developer mode → Load unpacked → dist/
Architecture
Strict split: core/ is a pure-TypeScript detection/policy/redaction engine with zero Chrome or DOM dependency; extension/ holds thin browser adapters. Detection math — Shannon entropy formula, thresholds, context scoring, confidence composition — is ported line-for-line from the backend. Worst-case scan ~90 ms in the isolated background process; the page's UI thread is never blocked. 245 tests, 97%+ coverage.
Rules
~62 rules across four JSON rule packs — secrets · PII · PCI · PHI — with Luhn / Verhoeff / IBAN checksum validators, placeholder and human-sentence false-positive filters, an entropy floor, and a high-entropy fallback (extractHighEntropyStrings). Known gap: NER-grade PERSON/ORG/LOCATION entities are server-side only in V1.
Policy
- Actions per category and domain: allow · warn · redact · block
- Category toggles, domain allow/deny lists, severity thresholds
- Redaction styles: replace, mask, partial-mask
- Prompt overlay UI · popup with stats/history · options page with import/export
- Works on CSP-strict (Google-family) pages
Enterprise sync, org-managed policies, and the VS Code port are phased roadmap items Coming Soon — see the roadmap.
Source: products/ai_shield/ (core/, extension/, docs/ROADMAP.md)