Lucairn Sdks

What Declade/lucairn-sdks MCP server does

Declade/lucairn-sdks MCP server provides the MCP entry point for Lucairn, an EU-based gateway that sits between an AI agent and an upstream language model. Its main MCP tool, chat_via_lucairn, sends prompts through a privacy pipeline before forwarding them to a selected provider.

The gateway detects personal data and replaces it with typed placeholders such as [PERSON_1], [EMAIL_2], or [IBAN_3]. Detection combines tenant-specific entity matching, Microsoft Presidio-based recognition, and an optional custom-trained shield available on the Enterprise tier. The supplied description covers German and English PII handling with custom recognisers.

After processing the request, Lucairn returns a signed certificate describing what was redacted, when processing occurred, and which sanitizer layer handled it. Certificates use an Ed25519 witness signature and include RFC 3161 timestamp and Sigstore Rekor anchoring information.

How it works

The MCP server runs locally through npx and communicates with the MCP client using the configured stdio command. The client sends a chat request to chat_via_lucairn, including the model identifier. Lucairn uses that identifier to select the upstream provider: Claude and Anthropic-prefixed models route to Anthropic, while GPT, OpenAI, and supported O-series prefixes route to OpenAI.

PII is replaced before the upstream model receives the prompt. Developer-tier responses retain the placeholders, which is useful for checking the redaction behavior. Pro and Enterprise tiers can restore the original values on the gateway before returning the response to the application. Enterprise self-hosted deployments can keep the complete stack inside the customer environment.

Setup and configuration

Install the server with:

npx -y @lucairn/mcp-server

Add the command to the MCP client configuration and set LUCAIRN_API_KEY. The README specifically lists Claude Desktop, Cursor, Cline, and Continue as compatible configuration targets. ANTHROPIC_API_KEY and OPENAI_API_KEY are optional BYOK variables; when supplied, the matching provider key is forwarded for the selected model and provider billing is direct.

A free Developer tier provides 500 requests per month without a credit card. Pro and Enterprise plans add capabilities including response re-linking, higher quotas, certificate JSON access, audit-event export, self-hosting, and optional custom PII training, depending on the plan.

Tools and capabilities

Declade/lucairn-sdks MCP server exposes the following documented MCP tool:

• chat_via_lucairn: sends a chat request through Lucairn's PII detection, placeholder substitution, provider routing, and certificate-generation pipeline.

The wider repository also contains TypeScript, Python, and Go SDKs. Those SDKs provide certificate summary and verification APIs, but the README identifies chat_via_lucairn as the MCP server tool. Every SDK response receives a certificate; HTML summaries are available on all tiers, while certificate JSON access and local Ed25519 verification are available on Pro and above.

Limitations and notes

The custom GPU-hosted PII shield is limited to Enterprise. Developer-tier output does not re-link placeholders to the original values. External RFC 3161 and Sigstore Rekor verification is currently exposed as pass-through metadata; full external anchor verification is planned for a later release.

The MCP server depends on a Lucairn account and API key. Provider credentials are needed when using BYOK routing, and the README does not document a hosted remote MCP endpoint. Declade/lucairn-sdks MCP server is MIT-licensed, but service quotas and tier-specific features are controlled by Lucairn rather than by the local package alone.