Lucairn MCP Server

Name: Lucairn MCP Server
Author: Declade

by Decladeversion 1.2.9i★ –iRuns on your computer

Registry nameio.github.Declade/lucairn-mcp-server

Install

Overview

Description from the maker (original English)

Pseudonymizes PII before your LLM and returns a cryptographically signed receipt per response.

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
UsageiNot measured yet★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Runs on your computer
Transport: stdio
Category: Search & AI memory
You need to fill in: LUCAIRN_API_KEY, ANTHROPIC_API_KEY, OPENAI_API_KEY

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 1 of 1 passed
Runs on your computer with your user’s permissions (files, network, apps).
You fill in yourself: LUCAIRN_API_KEY, ANTHROPIC_API_KEY, OPENAI_API_KEY, LUCAIRN_BASE_URL, LUCAIRN_TRANSPORT

Values marked secret are keys to your account. Never share them or paste them into a chat.

You need

npmNode.js installed (for the npx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

{
  "mcpServers": {
    "lucairn": {
      "command": "npx",
      "args": [
        "-y",
        "@lucairn/mcp-server"
      ],
      "env": {
        "LUCAIRN_API_KEY": "your-value",
        "ANTHROPIC_API_KEY": "your-value",
        "OPENAI_API_KEY": "your-value",
        "LUCAIRN_BASE_URL": "your-value",
        "LUCAIRN_TRANSPORT": "your-value"
      }
    }
  }
}

Run this in your terminal

claude mcp add lucairn --env LUCAIRN_API_KEY=your-value --env ANTHROPIC_API_KEY=your-value --env OPENAI_API_KEY=your-value --env LUCAIRN_BASE_URL=your-value --env LUCAIRN_TRANSPORT=your-value -- npx -y @lucairn/mcp-server

Fill in the empty values before running it.

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "lucairn": {
      "command": "npx",
      "args": [
        "-y",
        "@lucairn/mcp-server"
      ],
      "env": {
        "LUCAIRN_API_KEY": "your-value",
        "ANTHROPIC_API_KEY": "your-value",
        "OPENAI_API_KEY": "your-value",
        "LUCAIRN_BASE_URL": "your-value",
        "LUCAIRN_TRANSPORT": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "lucairn": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@lucairn/mcp-server"
      ],
      "env": {
        "LUCAIRN_API_KEY": "your-value",
        "ANTHROPIC_API_KEY": "your-value",
        "OPENAI_API_KEY": "your-value",
        "LUCAIRN_BASE_URL": "your-value",
        "LUCAIRN_TRANSPORT": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

Your choice stays on this device in a cookie; no account needed.

Values you fill in

LUCAIRN_API_KEY secret required env
Lucairn gateway API key (lcr_live_*). Issued at https://lucairn.eu/account/keys. Free tier requires BYOK upstream LLM keys (ANTHROPIC_API_KEY or OPENAI_API_KEY).
ANTHROPIC_API_KEY secret env
Upstream Anthropic API key. Used when the requested model is claude-* / anthropic-*. Required if you call Claude models on the free tier (BYOK).
OPENAI_API_KEY secret env
Upstream OpenAI API key. Used when the requested model routes to OpenAI. Required if you call OpenAI models on the free tier (BYOK).
LUCAIRN_BASE_URL env
Override the gateway URL. Defaults to https://gateway.lucairn.eu (production). Set this to point at a self-hosted Lucairn deployment.
LUCAIRN_TRANSPORT env
Transport mode for the MCP server. One of 'direct-http' (default; v1.1+ behavior) or 'stdio-bridge' (v1.2+ opt-in).

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 7, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account Declade, which owns the repo
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
– Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
– Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
… Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Search & AI memoryi

More stars than 0% of the other 7275 servers in this category
Published to the registry more recently than 26% of the other 7275 servers in this category
Basic checks equal to or better than 100% of the other 7275 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is Lucairn MCP Server safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

You need to fill in: LUCAIRN_API_KEY, ANTHROPIC_API_KEY, OPENAI_API_KEY

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed –, and the latest version (1.2.9) reached the registry 3 months ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Node.js on your computer.

What can I use instead?

In the same category: Context7, Codebase Memory, Exa

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README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

Lucairn SDKs

Official client libraries for [Lucairn](https://lucairn.eu) — 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 claude_desktop_config.json, Cursor's mcp.json, Cline's cline_mcp_settings.json, Continue, etc.):

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

Restart your client. The chat_via_lucairn 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:

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)

Detected PII is replaced with placeholders ([PERSON_1], [EMAIL_2], [IBAN_3], …) before the request reaches the upstream LLM.
The selected upstream model sees only the sanitized text. It never receives raw personal data.
The response is returned with a signed compliance certificate (Ed25519 witness signature + RFC 3161 timestamp + Sigstore Rekor inclusion proof).
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:

Model prefix	Upstream provider	BYOK env var
`claude-`, `anthropic-`	Anthropic	`ANTHROPIC_API_KEY`
`gpt-`, `openai-`, `o1-`, `o3-`, `o4-*`	OpenAI	`OPENAI_API_KEY`

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

Language	Package	Version	README
MCP server	`@lucairn/mcp-server`	1.2.7	mcp-server/README.md
TypeScript	`@lucairn/sdk`	1.1.1	ts/README.md
Python	`lucairn`	1.4.1	python/README.md
Go	`github.com/declade/lucairn-sdks/go`	v1.3.1	go/README.md

All SDKs are at parity at the observable level. Cross-language byte-equivalence is locked via shared Go-assembler-generated fixtures, so a certificate signed via one SDK verifies identically via the other two.

Get an API key

Pro adds response re-linking, programmatic certificate JSON access, audit-event export, and higher quota. Enterprise adds self-host, BYOK with provider-side billing isolation, and the optional custom-trained PII shield (priced per scope).

See https://lucairn.eu/pricing for the full tier comparison.

Verify a response

Every response through any SDK gets a signed Lucairn certificate. Two surfaces:

HTML summary — DPO-friendly, available on every tier including Developer (free). Use getCertificateSummary (TS) / get_certificate_summary (Python) / GetCertificateSummary (Go), or paste the certificate URL into https://lucairn.eu/verify.
JSON certificate + local Ed25519 verify — Pro tier and above. Use getCertificate + verifyCertificate (and language equivalents). The verifier is in-tree — see ts/src/verify-certificate/, python/src/lucairn/verify_certificate/, and the internal/verify package under go/.

Every claim, not only the witness signature — verifyCertificateChain / verify_certificate_chain / VerifyCertificateChain check each claim's own signature against per-service keys you pin, the claim bytes, the typed copies, the signed upstream-request hashes and the unsigned cert_tier. All three return identical results on the shared 98-case corpus in testdata/parity-corpus/. Render and decide only from the returned verified values; pass the expected request id so another turn's certificate is refused.

External RFC 3161 + Sigstore Rekor anchor verification is currently surfaced as pass-through metadata; full external anchor verification lands in a follow-up release.

Status

Production packages are versioned independently and tagged per the table above. Cross-language byte-equivalence is locked via shared fixtures. Follow CHANGELOG.md for release notes.

Contributing

See CONTRIBUTING.md. Security reports: SECURITY.md.

License

MIT — see LICENSE.

Lucairn MCP Server

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

Values you fill in

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Search & AI memoryi

Common questions

Alternatives

Context7

Codebase Memory

Exa

README from the maker

Lucairn SDKs

Quick start (MCP)

What it does

Provider routing

Per-language SDKs

Get an API key

Verify a response

Status

Links

Contributing

License