pii

Creates a builder for PII (personal information) detection rules. Detects email addresses, phone numbers, credit card numbers, and more.

Signature

const builder = pii(options?);

Parameters

Parameter	Type	Description
options.name	string	Rule name (auto-generated if omitted)

Methods

Method	Returns	Description
.exclude(...types)	DetectorBuilder	Exclude specified types from detection
.only(...types)	DetectorBuilder	Detect only specified types
.scope(...tools)	DetectorBuilder	Limit to specific tools (string | RegExp)
.block(message?)	Rule	Block on violation (severity: "error")
.warn(message?)	Rule	Warn on violation (severity: "warn")
.log(message?)	Rule	Log violation (severity: "info")

Detection Types

Type	Detects	Confidence
email	Email addresses	0.95
phone_international	International phone numbers (+1-555-123-4567)	0.85
phone_jp	Japanese phone numbers (03-1234-5678)	0.80
credit_card	Credit card numbers	0.90
my_number	Japanese My Number (12 digits)	0.70
ssn	US Social Security Numbers (XXX-XX-XXXX)	0.90
ip_address	IPv4 addresses	0.75

Returns

DetectorBuilder — terminal methods (.block(), .warn(), .log()) return a Rule.

Examples

Basic

import { pii } from "open-mcp-guardrails";

pii().block();

Exclude types

pii().exclude("ip_address").block();

Only specific types

pii().only("email", "credit_card").block();

Warn only

pii().warn("PII detected");

Scope to specific tools

pii().scope("filesystem__read_file").block();
pii().scope(/^filesystem__/).warn();

Derive from a common base

Builders are immutable, so you can safely derive rules from a shared base:

const base = pii();
const strict = base.block();
const lenient = base.exclude("ip_address").warn();

JSON Config

Equivalent configurations using guardrails.json:

{ "type": "pii", "action": "block" }

{ "type": "pii", "action": "block", "exclude": ["ip_address"] }

{ "type": "pii", "action": "block", "only": ["email", "credit_card"] }

{ "type": "pii", "action": "warn", "message": "PII detected" }

{ "type": "pii", "action": "block", "scope": ["filesystem__read_file"] }

{ "type": "pii", "action": "warn", "scope": ["/^filesystem__/"] }

Related

• secrets — Secret detection
• contentFilter — Custom pattern detection
• Detectors guide — All detector details