Ocultar PII Refinery — Claude MCP Extension

mcp-name: io.github.ocultar-dev/ocultar-pii

Zero-egress PII protection for Claude AI workflows. Runs entirely in your infrastructure — no data ever leaves your environment.

Tools

Prerequisites

• Ocultar Refinery running locally:

  docker compose up
  

• Python 3.10+

Installation

pip install ocultar-claude-mcp

Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "ocultar-pii": {
      "command": "ocultar-claude-mcp",
      "env": {
        "OCULTAR_URL": "http://localhost:4141",
        "OCULTAR_API_KEY": "your-api-key"
      }
    }
  }
}

Claude Code (CLI)

claude mcp add ocultar-pii -- ocultar-claude-mcp

Or add to .claude/settings.json:

{
  "mcpServers": {
    "ocultar-pii": {
      "command": "ocultar-claude-mcp",
      "env": {
        "OCULTAR_URL": "http://localhost:4141",
        "OCULTAR_API_KEY": "your-api-key"
      }
    }
  }
}

Environment Variables

Usage

Once connected, Claude will automatically call refine_text when you ask it to handle sensitive data. You can also ask explicitly:

"Refine this before processing: John Smith's email is john@example.com, SSN 123-45-6789"

Claude returns:

{
  "cleanText": "John [NAME_a1b2c3d4e5f6a7b8]'s email is [EMAIL_9c8f7a1b2d3e4f50], SSN [SSN_3a1b2c4d5e6f7081]",
  "tokenMap": {
    "[NAME_a1b2c3d4e5f6a7b8]": "NAME",
    "[EMAIL_9c8f7a1b2d3e4f50]": "EMAIL",
    "[SSN_3a1b2c4d5e6f7081]": "SSN"
  }
}

For authorized workflows that need to restore PII after AI processing:

"Reveal these tokens: [EMAIL_9c8f7a1b2d3e4f50], [SSN_3a1b2c4d5e6f7081]"

This call is recorded in the immutable Ed25519-signed audit log.

Why Zero-Egress?

The Ocultar Refinery runs entirely on your machine. The MCP server communicates only with localhost — no telemetry, no cloud calls, no supply chain attack surface. If the Refinery is unreachable, both tools fail closed: raw PII is never forwarded.

Security Model

• refine_text is safe to expose to any Claude session
• reveal_tokens requires OCULTAR_AUDITOR_TOKEN and every call is logged with actor, timestamp, and Ed25519 signature in the audit trail
• The Refinery's vault uses AES-256-GCM with HKDF-SHA256 key derivation — tokens are useless without the master key

License

AGPLv3 — see LICENSE. Commercial licensing available for organizations that cannot comply with AGPLv3's source-disclosure requirements — see COMMERCIAL_LICENSE.md.