Lucairn MCP server

Lucairn SDKs

Official client libraries for Lucairn — an EU-based privacy-preserving AI gateway. Lucairn sits between your application (or AI agent) and the upstream LLM provider you choose, removes personal data from prompts before the model ever sees them, and returns a signed Lucairn Certificate proving what was redacted, when, and by which sanitizer layer.

This monorepo hosts four packages at parity:

• @lucairn/mcp-server — Model Context Protocol server (one-line npx install for Claude Desktop, Cursor, Cline, Continue, …)
• @lucairn/sdk — TypeScript / Node SDK
• lucairn — Python SDK
• github.com/declade/lucairn-sdks/go — Go SDK

Quick start (MCP)

For most agent use cases, the fastest path is the MCP server. No build step, no install — npx runs it on demand:

npx -y @lucairn/mcp-server

Add it to your MCP client config (Claude Desktop's claudedesktopconfig.json, Cursor's mcp.json, Cline's clinemcpsettings.json, Continue, etc.):

{
  "mcpServers": {
    "lucairn": {
      "command": "npx",
      "args": ["-y", "@lucairn/mcp-server"],
      "env": {
        "LUCAIRN_API_KEY": "<your_lucairn_api_key>",
        "ANTHROPIC_API_KEY": "<optional_byok_anthropic_key>",
        "OPENAI_API_KEY": "<optional_byok_openai_key>"
      }
    }
  }
}

Restart your client. The chatvialucairn tool becomes available immediately. See mcp-server/README.md for full details.

What it does

Each request through any Lucairn SDK follows the same pipeline:

1. PII detection runs on every user message in three layers:

• Layer 1 — Known-entity matching (your tenant's named entities)
• Layer 2 — Presidio NER (names, emails, IBANs, addresses, phone numbers, customer IDs, …)
• Layer 3 — GPU-hosted custom-trained PII shield (Enterprise tier only, optionally trained on your domain corpus)

1. Detected PII is replaced with placeholders ([PERSON1], [EMAIL2], [IBAN3], …) before** the request reaches the upstream LLM.
2. The selected upstream model sees only the sanitized text. It never receives raw personal data.
3. The response is returned with a signed compliance certificate (Ed25519 witness signature + RFC 3161 timestamp + Sigstore Rekor inclusion proof).
4. Response handling depends on tier:

• Developer (free) — placeholders are returned verbatim. Useful for testing the redaction surface.
• Pro / Enterprise — placeholders are re-linked back to the originals on the gateway before the response reaches your application.

For Lucairn-hosted Developer-tier callers, on-gateway pseudonymization happens before your LLM sees the request. Enterprise self-host deployments can run the entire stack inside the customer environment, in which case no raw identity data leaves that environment at all.

Provider routing

The gateway picks the upstream provider from the model parameter you send:

Cross-provider BYOK shipped in @lucairn/mcp-server@1.1.0 — set one or both keys in the same MCP config and the server forwards the matching one as X-Upstream-Key per request, so your provider account is billed directly.

Per-language SDKs

Shortened. The full README is on GitHub.