Configure PII Scrubbing

Configure PII scrubbing to automatically redact sensitive information from MCP responses before they’re logged or returned to clients.

Prerequisites

Control Plane
YAML

Golf Control Plane account with Admin role
MCP server registered in Control Plane

Understanding the 3-layer policy hierarchy

PII scrubbing follows the same 3-layer hierarchy as other Golf Gateway policies:

Layer	Where Configured	Scope
Organization	Control Plane > Settings > Policies	All gateways & servers
Gateway	Control Plane > Gateway > Policies	All servers on this gateway
Server	Control Plane > Server > Policies	Single MCP server

Policy Merge Rules:

Sensitive fields: Combined from ALL layers (union)
Whitelist fields: Combined from ALL layers (union)
Custom rules: Combined from ALL layers (union)
Custom entities: Combined from ALL layers (union)
Enabled flag: True if ANY layer enables scrubbing

Set organization-wide defaults for common PII types, then add server-specific rules for domain-specific data.

Enable PII scrubbing

Control Plane
YAML

Organization defaults:

Go to Settings > Policies
Find the PII Protection section
Enable PII Scrubbing
Configure default sensitive field names
Click Save

Gateway overrides:

Go to Gateways > select a gateway > Policies
Find the PII Protection section
Add gateway-specific sensitive fields
Click Save

Server-level configuration:

Go to MCP Servers > select a server
Open the Policies tab > PII
Enable PII Protection
Add custom sensitive field names
Click Save

Gateway-level defaults (applies to all servers):

gateway_policy:
  scrubbing:
    enabled: true
    sensitive_fields:
      - password
      - api_key
      - secret
    whitelist_fields:              # Fields that should NEVER be scrubbed
      - connection_id
      - session_id
      - cursor
      - tool_name
    recognizers:
      - entity_type: EMAIL_ADDRESS
        enabled: true
      - entity_type: CREDIT_CARD
        enabled: true
      - entity_type: URL
        enabled: false             # Disable URL scrubbing

Server-level overrides (merged on top of gateway defaults):

servers:
  - name: my-server
    url: http://localhost:3001
    security:
      enabled: true
      sensitive_fields:
        - api_key
        - password
      whitelist_fields:
        - report_id
      recognizers:
        - entity_type: EMAIL_ADDRESS
          enabled: true
          replacement: "[PII_EMAIL]"   # Custom replacement for this server

Built-in PII detection

Golf Gateway detects many entity types by default. Common examples include:

Entity Type	Example
`CREDIT_CARD`	4111-1111-1111-1111
`EMAIL_ADDRESS`	user@example.com
`PHONE_NUMBER`	(415) 555-1234
`US_SSN`	123-45-6789
`IP_ADDRESS`	192.168.1.1
`US_BANK_NUMBER`	1234567890
`URL`	https://example.com
`IBAN_CODE`	DE89370400440532013000

Additional supported types include PERSON, LOCATION, ORGANIZATION (via GLiNER), US_DRIVER_LICENSE, US_PASSPORT, JWT_TOKEN, and more.

Add custom scrubbing rules

For patterns not covered by built-in detection, add custom rules:

Control Plane
YAML

Go to the appropriate level (Settings, Gateway, or Server > Policies)
Find the PII Protection section
Click Add Custom Rule
Enter the regex pattern and select the masking method
Click Save

Add custom rules at the gateway level (applies to all servers) or server level (per-server overrides):

# Gateway-level custom rules
gateway_policy:
  scrubbing:
    enabled: true
    custom_rules:
      - pattern: "sk-[a-zA-Z0-9]+"       # API keys
        method: mask

# Server-level custom rules (merged with gateway rules)
servers:
  - name: my-server
    url: http://localhost:3001
    security:
      enabled: true
      custom_rules:
        - pattern: "LINEAR-[A-Z]+-[0-9]+"  # Linear issue IDs
          method: mask
        - pattern: "TXN-\\d+"               # Transaction IDs
          method: replace
          replacement: "[TXN_ID]"

Masking methods:

Method	Behavior	Example
`mask`	Replace with `[REDACTED]`	`sk-abc123` → `[REDACTED]`
`hash`	Replace with SHA256 hash (first 16 chars)	`sk-abc123` → `a1b2c3d4e5f6g7h8`
`remove`	Remove the value entirely	`sk-abc123` → “
`replace`	Replace with custom text	`sk-abc123` → `[API_KEY]`

Configure per-server scrubbing

Different servers can have different scrubbing settings:

Control Plane
YAML

Configure each server individually through MCP Servers > server > Policies > PII.

servers:
  # Internal tools - minimal scrubbing
  - name: internal-tools
    url: http://localhost:3001
    security:
      enabled: true
      sensitive_fields: [password]
      whitelist_fields: [file_path, tool_name]

  # External API - comprehensive scrubbing
  - name: external-api
    url: http://localhost:3002
    security:
      enabled: true
      sensitive_fields: [api_key, bearer_token, secret, password]
      custom_rules:
        - pattern: "Bearer [a-zA-Z0-9\\-_]+"
          method: mask
      recognizers:
        - entity_type: EMAIL_ADDRESS
          enabled: true
          replacement: "[PII_EMAIL]"
        - entity_type: CREDIT_CARD
          enabled: true
          replacement: "[PII_CARD]"

Verify scrubbing is active

In Admin Portal, go to Logs
Select a session and find a request containing PII
In the security pipeline, look for the PII Scrubbed step
Verify sensitive data shows entity-specific placeholders like [EMAIL], [SSN], or [MASKED]

Fields never scrubbed

These fields are preserved for audit purposes and are never scrubbed regardless of configuration:

connection_id, session_id, correlation_id
timestamp, event_type, method
user.email, user.sub (for compliance)

You can also configure additional fields to be excluded from scrubbing using whitelist_fields at the gateway or server level. This is useful for protecting operational data like file paths, tool names, or cursor tokens from accidental scrubbing.

Troubleshooting

PII not being detected: Verify scrubbing is enabled at all policy levels (org, gateway, server)
Custom pattern not matching: Test your regex pattern - Golf Gateway uses Python regex syntax
Too much data being scrubbed: Check if multiple layers are adding overlapping rules

Set Up Server RBAC - Access control
Golf Gateway Overview - Policy engine architecture

Overview

Guides

Reference

Support

Prerequisites

Understanding the 3-layer policy hierarchy

Enable PII scrubbing

Built-in PII detection

Add custom scrubbing rules

Configure per-server scrubbing

Verify scrubbing is active

Fields never scrubbed

Troubleshooting

​Prerequisites

​Understanding the 3-layer policy hierarchy

​Enable PII scrubbing

​Built-in PII detection

​Add custom scrubbing rules

​Configure per-server scrubbing

​Verify scrubbing is active

​Fields never scrubbed

​Troubleshooting

​Related guides

Prerequisites

Understanding the 3-layer policy hierarchy

Enable PII scrubbing

Built-in PII detection

Add custom scrubbing rules

Configure per-server scrubbing

Verify scrubbing is active

Fields never scrubbed

Troubleshooting

Related guides