# gate

> gate is a PII-filtering CLI that transparently intercepts AI agent database query commands and redacts sensitive data before it reaches the model context.

gate sits between your AI agent (Claude Code, Cursor, Copilot) and your database tools (psql, dbt, BigQuery CLI) or MCP servers. When the AI runs a query, gate intercepts the result, scans every value for PII, and returns a redacted version to the model. The AI can still reason about the data; it just never sees the raw personal information.

## Install

```
brew tap GaaraZhu/gate && brew install gate
```

## Connect to Claude Code

```
gate init
```

This registers gate as a Claude Code Bash hook. It is idempotent.

## MCP proxy

```
gate mcp -- npx -y @modelcontextprotocol/server-postgres postgresql://...
```

Wrap any MCP server command with `gate mcp --` to proxy and redact its tool responses.

## What gate detects

- Email addresses
- Phone numbers (international formats)
- Full names (heuristic)
- Credit card numbers (Luhn-validated)
- NZ IRD numbers (checksum-validated)
- NZ NHI numbers (check-character validated, old and new formats)
- AU Tax File Numbers / TFN (checksum-validated)
- AU Business Numbers / ABN (checksum-validated)
- AU Medicare numbers (check-digit validated)
- Passport numbers
- Dates of birth
- Custom patterns via ~/.config/gate/config.yaml

## Two-layer detection

Gate 1: parses the SQL query, marks sensitive column names before the query runs.
Gate 2: scans every value in the result set with the full pattern library.

Gate 2 false negatives are treated as worse than false positives — when in doubt, gate redacts.

## Configuration

Config lives at ~/.config/gate/config.yaml. Example:

```yaml
enabled: true
patterns:
  - name: internal_account_id
    regex: 'ACC-\d{8}'
    label: account_id
forced_columns:
  - customer_id
  - account_number
```

## AU/NZ Compliance Pack

For regulated organisations in Australia and New Zealand, GZhu Limited offers a Compliance Pack: signed attestation, deployment runbook, and ongoing monitoring. See https://gate.gzhu.co.nz/au-nz-pack

## Source

MIT licensed. Source: https://github.com/GaaraZhu/gate
Documentation: https://gate.gzhu.co.nz/docs