🇨🇭 Part of the Swiss Public Data MCP Portfolio
MCP Server for the Swiss Federal Commercial Register (Zefix/Handelsregister) and supporting reference data
register-mcp provides AI-native access to the Swiss Federal Commercial Register via the Zefix REST API, all without authentication:
| Source | Data | API |
|---|---|---|
| Zefix (Handelsregister) | Swiss companies, legal forms, SHAB mutations | ZefixREST v1 |
| SHAB | Official Gazette of Commerce — mutation publications | Embedded in Zefix |
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?"
- 🏛️ 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)
- Python 3.11+
- uv (recommended) or pip
# 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# stdio (for Claude Desktop)
python -m register_mcp.server
# SSE (cloud deployment) — MCP_API_KEY is REQUIRED
MCP_API_KEY=$(openssl rand -hex 32) MCP_TRANSPORT=sse PORT=8000 \
python -m register_mcp.serverWhen running with MCP_TRANSPORT=sse, the server enforces:
- Bearer-token auth — set
MCP_API_KEYto a secret string. Clients must sendAuthorization: Bearer <key>on every request. Missing or wrong → HTTP 401. The server refuses to start withoutMCP_API_KEYset. - Rate limiting — sliding window per bearer-token hash. Defaults: 60 req / 60 s.
Tunable via
MCP_RATE_LIMITandMCP_RATE_WINDOW. Exceeding the limit returns HTTP 429 withRetry-After. - Structured JSON logging — every tool call emits one line to stderr with
tool,status,latency_ms. Auth failures and rate-limit events are logged at WARNING level. Configure verbosity withLOG_LEVEL(defaultINFO). - Reference-data cache — Zefix legal-forms are cached for 24h
(
LEGAL_FORMS_TTLseconds) to avoid an extra upstream call per tool invocation. - Egress allow-list — outbound HTTP is restricted to
www.zefix.admin.chvia anhttpxrequest hook that also fires on redirects. ALocationheader pointing elsewhere raisesEgressDeniedand is never followed. Override withMCP_ALLOWED_HOSTS=host1,host2(comma-separated, lower-case). - Optional OpenTelemetry tracing — install with
pip install register-mcp[otel]and setOTEL_EXPORTER_OTLP_ENDPOINT(e.g.http://otel-collector:4318/v1/traces). Without the extra or without the env var the server stays silent — no hard dependency on the OTel SDK.
For multi-instance deployments, place a real gateway (Cloudflare, Railway internal networking, an API-Gateway with Redis-backed rate limiting) in front of the in-memory limiter, which is per-process by design.
A minimal multi-stage Dockerfile ships with the repo. The image runs as a
non-root mcp user; dependencies are resolved from uv.lock (uv sync --frozen), so the build is reproducible.
docker build -t register-mcp:local .
docker run --rm -p 8000:8000 \
-e MCP_TRANSPORT=sse \
-e MCP_API_KEY="$(openssl rand -hex 32)" \
register-mcp:localFor 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 --buildSee 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"
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
For use via claude.ai in the browser (e.g. on managed workstations without local software):
Render.com (recommended):
- Push/fork the repository to GitHub
- On render.com: New Web Service → connect GitHub repo
- Set start command:
python -m register_mcp.server --http --port 8000 - In claude.ai under Settings → MCP Servers, add:
https://your-app.onrender.com/sse
💡 "stdio for the developer laptop, SSE for the browser."
| Tool | Description |
|---|---|
zefix_search_companies |
Search companies by name, canton, legal form |
zefix_get_company |
Full company profile by internal EHRAID |
zefix_get_company_by_uid |
Company lookup by UID (CHE-xxx.xxx.xxx) |
zefix_verify_company |
Quick active/dissolved status check |
zefix_list_legal_forms |
All Swiss legal forms with IDs |
zefix_list_municipalities |
Swiss municipalities with BFS IDs |
| Query | Tool |
|---|---|
| "Is Lehrmittelverlag Zürich AG active?" | zefix_verify_company |
| "Look up CHE-108.954.978" | zefix_get_company_by_uid |
| "Find companies named Migros in canton ZH" | zefix_search_companies |
| "List all Swiss legal forms" | zefix_list_legal_forms |
| "Show municipalities in canton Bern" | zefix_list_municipalities |
┌─────────────────┐ ┌──────────────────────────────┐ ┌──────────────────────────┐
│ Claude / AI │────▶│ register-mcp │────▶│ Zefix (Handelsregister) │
│ (MCP Host) │◀────│ (MCP Server) │◀────│ ZefixREST/api/v1 │
└─────────────────┘ │ │ └──────────────────────────┘
│ 6 Tools │
│ Stdio | SSE │
│ No authentication required │
└──────────────────────────────┘
| Source | Protocol | Coverage | Auth |
|---|---|---|---|
| Zefix (Phase 1) | REST/JSON | Swiss companies, legal forms, SHAB | None |
| ZefixPublicREST (Phase 2) | REST/JSON | Signatories, capital, full history | Basic Auth (free) |
| UID Register (Phase 3) | SOAP | MwSt, NOGA codes, cross-validation | Public (20 req/min) |
| Phase | API | Auth | Status |
|---|---|---|---|
| Phase 1 | ZefixREST/api/v1 |
None | Current |
| Phase 2 | ZefixPublicREST/api/v1 |
Basic Auth (free, email zefix@bj.admin.ch) | Planned |
| Phase 3 | UID-Register SOAP | Public (20 req/min) | Planned |
Phase 2 will add: signatory details, share capital, full historical entries. Phase 3 will add: MwSt status, NOGA industry codes, cross-register validation.
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
- 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 zefix@bj.admin.ch
| API | Limit | Notes |
|---|---|---|
| ZefixREST (Phase 1) | Not officially documented | Throttling possible under heavy load — retry after 1–2 s |
| ZefixPublicREST (Phase 2) | Not officially documented | Requires prior registration (free) |
| UID-Register SOAP (Phase 3) | 20 req/min | Hard limit, publicly documented |
- 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
- 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.
- 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
📽️ Terminal GIF coming soon — see
docs/demo/to generate it locally with 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# Unit tests (no API key required)
PYTHONPATH=src pytest tests/ -m "not live"
# Integration tests (live API calls)
pytest tests/ -m "live"See CHANGELOG.md
See CONTRIBUTING.md
MIT License — see LICENSE
Hayal Oezkan · malkreide
- 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
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"
]
}
}
}