🇨🇭 Part of the [Swiss Public Data MCP Portfolio](https://github.com/malkreide)

🏛️ register-mcp

MCP Server for the Swiss Federal Commercial Register (Zefix/Handelsregister) and supporting reference data

🇩🇪 Deutsche Version

Overview

register-mcp provides AI-native access to the Swiss Federal Commercial Register via the Zefix REST API, all without authentication:

Designed for Swiss public administration use cases: vendor verification, contract partner due diligence, procurement screening, and supplier onboarding — all via natural language queries.

Anchor demo query: "We want to sign a framework agreement with Lehrmittelverlag Zürich AG. Is the company active in the commercial register, what is its stated corporate purpose, and have there been any SHAB mutations in the past two years?"

Features

• 🏛️ 6 tools for company search, verification, and reference data
• 🔍 `zefix_verify_company` — quick active/dissolved status check
• 🌐 Bilingual output (Markdown / JSON)
• 🔓 No API key required — open data from zefix.admin.ch
• ☁️ Dual transport — stdio (Claude Desktop) + SSE (cloud)

Prerequisites

• Python 3.11+
• uv (recommended) or pip

Installation

# Clone the repository
git clone https://github.com/malkreide/register-mcp.git
cd register-mcp

# Install
pip install -e .
# or with uv:
uv pip install -e .

Or with uvx (no permanent installation):

uvx register-mcp

Quickstart

# stdio (for Claude Desktop)
python -m register_mcp.server

# SSE (cloud deployment) — MCP_API_KEY is REQUIRED
MCP_API_KEY=$(openssl rand -hex 32) MCP_TRANSPORT=sse PORT=8000 \
  python -m register_mcp.server

SSE / Cloud Deployment

When running with MCP_TRANSPORT=sse, the server enforces:

• Bearer-token auth — set MCP_API_KEY to a secret string. Clients must send

Authorization: Bearer <key> on every request. Missing or wrong → HTTP 401. The server refuses to start without MCP_API_KEY set.

• Rate limiting — sliding window per bearer-token hash. Defaults: 60 req / 60 s.

Tunable via MCP_RATE_LIMIT and MCP_RATE_WINDOW. Exceeding the limit returns HTTP 429 with Retry-After.

• Structured JSON logging — every tool call emits one line to stderr with

tool, status, latency_ms. Auth failures and rate-limit events are logged at WARNING level. Configure verbosity with LOG_LEVEL (default INFO).

• Reference-data cache — Zefix legal-forms are cached for 24h

(LEGAL_FORMS_TTL seconds) to avoid an extra upstream call per tool invocation.

• Egress allow-list — outbound HTTP is restricted to www.zefix.admin.ch

via an httpx request hook that also fires on redirects. A Location header pointing elsewhere raises EgressDenied and is never followed. Override with MCP_ALLOWED_HOSTS=host1,host2 (comma-separated, lower-case).

• Optional OpenTelemetry tracing — install with pip install register-mcp[otel]

and set OTEL_EXPORTER_OTLP_ENDPOINT (e.g. http://otel-collector:4318/v1/traces). Without the extra or without the env var the server stays silent — no hard dependency on the OTel SDK.

For multi-instance deployments, place a real gateway (Cloudflare, Railway internal networking, an API-Gateway with Redis-backed rate limiting) in front of the in-memory limiter, which is per-process by design.

Container deployment

A minimal multi-stage Dockerfile ships with the repo. The image runs as a non-root mcp user; dependencies are resolved from uv.lock (uv sync --frozen), so the build is reproducible.

docker build -t register-mcp:local .

docker run --rm -p 8000:8000 \
  -e MCP_TRANSPORT=sse \
  -e MCP_API_KEY="$(openssl rand -hex 32)" \
  register-mcp:local

For local iteration there is a compose.yaml with read_only, cap_drop: ALL and no-new-privileges:

MCP_API_KEY=$(openssl rand -hex 32) docker compose up --build

See SECURITY.md for hardening notes (egress restriction, key rotation, SIEM forwarding).

Try it immediately in Claude Desktop:

"Is Lehrmittelverlag Zürich AG active in the commercial register?" "Look up the company with UID CHE-108.954.978" "List all Swiss legal forms"

Configuration

Claude Desktop

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

{
  "mcpServers": {
    "register": {
      "command": "python",
      "args": ["-m", "register_mcp.server"]
    }
  }
}

Or with uvx:

{
  "mcpServers": {
    "register": {
      "command": "uvx",
      "args": ["register-mcp"]
    }
  }
}

Config file locations:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json

Cloud Deployment (SSE for browser access)

For use via claude.ai in the browser (e.g. on managed workstations without local software):

Render.com (recommended):

1. Push/fork the repository to GitHub
2. On render.com: New Web Service → connect GitHub repo
3. Set start command: python -m register_mcp.server --http --port 8000
4. In claude.ai under Settings → MCP Servers, add: https://your-app.onrender.com/sse

💡 "stdio for the developer laptop, SSE for the browser."

Available Tools

Example Use Cases

Architecture

┌─────────────────┐     ┌──────────────────────────────┐     ┌──────────────────────────┐
│   Claude / AI   │────▶│       register-mcp            │────▶│  Zefix (Handelsregister)  │
│   (MCP Host)    │◀────│       (MCP Server)            │◀────│  ZefixREST/api/v1        │
└─────────────────┘     │                              │     └──────────────────────────┘
                        │  6 Tools                     │
                        │  Stdio | SSE                 │
                        │  No authentication required  │
                        └──────────────────────────────┘

Data Source Characteristics

Phased Implementation

Phase 2 will add: signatory details, share capital, full historical entries. Phase 3 will add: MwSt status, NOGA industry codes, cross-register validation.

Project Structure

register-mcp/
├── src/register_mcp/
│   ├── __init__.py              # Package
│   └── server.py                # 6 tools (Zefix + reference data)
├── tests/
│   └── test_server.py           # Unit + integration tests (mocked HTTP)
├── docs/demo/
│   ├── demo.tape                # vhs recording script → demo.gif
│   ├── demo.py                  # Standalone CLI demo (live Zefix API)
│   └── README.md                # How to generate the demo GIF
├── .github/workflows/ci.yml     # GitHub Actions (Python 3.11/3.12/3.13)
├── pyproject.toml
├── CHANGELOG.md
├── CONTRIBUTING.md
├── LICENSE
├── README.md                    # This file (English)
└── README.de.md                 # German version

Known Limitations

• Search by canton without a name filter may return API errors (Zefix API limitation)
• SHAB publication message text contains XML-style markup (<FT TYPE="F">...)
• Phase 1 API may be rate-limited under heavy load; retry after a short delay
• ZefixPublicREST (new API) requires registration: email [email protected]

Safety & Limits

Rate Limits

Data Privacy

• Read-only access — all tools carry readOnlyHint: True; the server performs no write, delete, or mutation operations against any API
• No data storage — the server acts as a stateless proxy; no company data is persisted, cached, or logged beyond the current request
• Public register data only — the Zefix Handelsregister is a public federal register (HRegV); data returned is legally public information, not personal data in the sense of DSG/GDPR
• No personal tracking — the server does not transmit user identity, query history, or session data to zefix.admin.ch

Terms of Service & Data Sources

• Zefix API ToS: Usage of the Zefix REST API is governed by the zefix.admin.ch terms of use. The data is published under the Open Government Data (OGD) Switzerland principles.
• SHAB: Swiss Official Gazette of Commerce — published by the Federal Chancellery (BK). Public by law.
• Institutional use: This server is designed for read-only queries in public administration workflows. Not suitable for mass harvesting or automated surveillance use cases.

Security

• No credentials are stored or transmitted (Phase 1)
• Phase 2 credentials (ZEFIX_USER, ZEFIX_PASSWORD) are passed via environment variables only — never hardcoded
• All HTTP calls use HTTPS exclusively
• Tool inputs are validated via Pydantic v2 before any API call is made

Demo

register-mcp demo

📽️ Terminal GIF coming soon — see [`docs/demo/`](docs/demo/) to generate it locally with [vhs](https://github.com/charmbracelet/vhs)

Example interaction:

User:  "Is Lehrmittelverlag Zürich AG active in the commercial register?"

→ Tool: zefix_verify_company(name="Lehrmittelverlag Zürich AG")

Claude: ✅ Lehrmittelverlag Zürich AG is ACTIVE in the Handelsregister.
        UID: CHE-109.741.634 | Canton: ZH | Legal form: AG
        Last SHAB mutation: 2024-06-15

→ More use cases by audience →

To generate the demo GIF locally:

# Install vhs (macOS/Linux)
brew install vhs        # macOS
# or: go install github.com/charmbracelet/vhs@latest

# Generate
vhs docs/demo/demo.tape
# → outputs docs/demo/demo.gif

Testing

# Unit tests (no API key required)
PYTHONPATH=src pytest tests/ -m "not live"

# Integration tests (live API calls)
pytest tests/ -m "live"

Changelog

See CHANGELOG.md

Contributing

See CONTRIBUTING.md

License

MIT License — see LICENSE

Author

Hayal Oezkan · malkreide

Credits & Related Projects

• Zefix: zefix.admin.ch — Swiss Federal Commercial Register (BJ/FOJ)
• SHAB: Swiss Official Gazette of Commerce — mutation publications
• Protocol: Model Context Protocol — Anthropic / Linux Foundation
• Related: fedlex-mcp — Commercial register ordinance (HRegV)
• Related: zurich-opendata-mcp — Company seat + geodata
• Related: swiss-statistics-mcp — Industry statistics by NOGA
• Related: swiss-snb-mcp — Economic indicators
• Portfolio: Swiss Public Data MCP Portfolio

<!-- mcp-name: io.github.malkreide/register-mcp -->

<!-- BEGIN GENERATED: install -->

Installation

Run via uv's uvx — no clone or manual install needed. Add to your MCP client config (mcpServers for Claude Desktop, Cursor and Windsurf; use a top-level servers key for VS Code in .vscode/mcp.json):

{
  "mcpServers": {
    "register-mcp": {
      "command": "uvx",
      "args": [
        "register-mcp"
      ]
    }
  }
}

<!-- END GENERATED: install -->