🇨🇭 Part of the Swiss Public Data MCP Portfolio

⚖️ fedlex-mcp

MCP Server for Swiss federal law, consultations & official terminology — search the SR, monitor consultation deadlines, and translate terms across the national languages via Claude Desktop or Claude.ai

🇩🇪 Deutsche Version

Overview

fedlex-mcp connects AI assistants (Claude) with three official Swiss SPARQL data sources:

1. Federal law via the Fedlex SPARQL endpoint — the Systematic Compilation (SR), Official Compilation (AS), Federal Gazette (BBl) and treaties.
2. Consultations (Vernehmlassungen) via the same Fedlex endpoint (jolux:Consultation) — the pre-parliamentary phase in which anyone can comment on a draft.
3. TERMDAT, the Federal Chancellery's terminology database, via the LINDAS SPARQL endpoint — official term equivalents across de/fr/it/rm/en.

All three are SPARQL-based, which is exactly why they live in one server rather than three: no new technology stack, only new queries against known patterns.

Metaphor: USB-C for federal law. Fedlex tells you what you have to respond to. TERMDAT tells you what it is called in the other national languages.

Features

• ⚖️ 12 tools, 2 resources across federal law, consultations and terminology
• 🔍 SPARQL-powered — two isolated endpoints (Fedlex + LINDAS), no shared failure mode
• 🌐 5 languages — German, French, Italian, Romansh, plus English for terminology
• 🔓 No API key required — all data under open reuse licences
• ☁️ Dual transport — stdio (Claude Desktop) + Streamable HTTP (cloud)

Anchor demo query

"Which education-related consultations are currently open, until when does the deadline run, which office is in charge — and what are the key technical terms in French and Italian for the response?"

A single conversation chains three tools across two endpoints:

fedlex_get_open_consultations(topic="education")
   → fedlex_get_consultation(event_id="proj/2026/71/cons_1")
   → termdat_lookup_term(term="Volksschule", target_languages=["fr","it"])

Every open consultation carries deadline, days_remaining (computed at request time in Europe/Zurich, 0 = deadline is today) and a derived status — an expired consultation never shows up as running. Fedlex says what you must respond to and by when; TERMDAT says how to name it in the other national languages.

Use topic="education", not keyword="Volksschule". Fedlex consultations have no subject taxonomy — filtering is free-text over the title, and the word "Volksschule" appears in zero consultation titles. The topic filter expands to a disclosed keyword union (Bildung, Schule, Berufsbildung, Hochschule, …) and reports exactly which terms it searched.

Prerequisites

• Python 3.11+
• uv (recommended) or pip

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

Installation from source

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

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

Or with uvx (no permanent installation):

uvx fedlex-mcp

Quickstart

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

# Streamable HTTP (port 8000)
python -m fedlex_mcp.server --http --port 8000

Try it immediately in Claude Desktop:

"Show me all valid federal laws on vocational training" "What does the Data Protection Act say? Is it still in force?" "Which consultations on education are open right now, and until when?" "What is 'Volksschule' called in French and Italian in official terminology?"

Configuration

Claude Desktop

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

{
  "mcpServers": {
    "fedlex": {
      "command": "python",
      "args": ["-m", "fedlex_mcp.server"]
    }
  }
}

Or with uvx:

{
  "mcpServers": {
    "fedlex": {
      "command": "uvx",
      "args": ["fedlex-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 fedlex_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."

Demo

Available Tools

Example Use Cases

→ More use cases by audience →

Architecture

Two isolated SPARQL endpoints behind one server. Separate httpx clients and timeouts mean a LINDAS outage never breaks the fedlex_* tools, and vice versa.

+-------------------+     +------------------------------+     +--------------------------+
|   Claude / AI     |---->|  Fedlex MCP                  |---->|  Fedlex SPARQL Endpoint  |
|   (MCP Host)      |<----|  (MCP Server)                |<----|  fedlex.data.admin.ch    |
+-------------------+     |                              |     |  (law + consultations)   |
                          |  12 Tools . 2 Resources      |     +--------------------------+
                          |  Stdio | SSE                 |
                          |                              |     +--------------------------+
                          |  Isolated clients:           |---->|  LINDAS SPARQL Endpoint  |
                          |   - Fedlex  (law + cons.)     |<----|  lindas.admin.ch/query   |
                          |   - LINDAS  (TERMDAT)         |     |  (fch/termdat, TERMDAT)  |
                          |                              |     +--------------------------+
                          |  No authentication required  |
                          +------------------------------+

Data Model

JOLux Ontology — federal law (Fedlex)

jolux:ConsolidationAbstract  <-  SR entry
  +-- jolux:isRealizedBy  ->  jolux:Expression (URI ends in /de, /fr, /it, /rm)
     +-- jolux:title               "Federal Act of 19 June 1992 on Data Protection"
     +-- jolux:titleShort          "DSG"
     +-- jolux:historicalLegalId   "235.1"

jolux:inForceStatus:  .../0 In force  ·  .../1 No longer published in SR  ·  .../3 No longer in force

JOLux Ontology — consultations (Fedlex, same endpoint)

jolux:Consultation
  +-- jolux:eventId                     "proj/2026/71/cons_1"
  +-- jolux:eventTitle                  multilingual (de/fr/it)
  +-- jolux:eventDescription            multilingual
  +-- jolux:consultationStatus          -> vocabulary URI (0..6, /2 = "Laufend"/running)
  +-- jolux:foreseenImpactToLegalResource  -> the legal resource it will amend (link to SR)
  +-- jolux:hasSubTask  ->  ?t
        +-- jolux:eventStartDate                      <- opened_on
        +-- jolux:eventEndDate                        <- the deadline (xsd:date, calendar day)
        +-- jolux:institutionInChargeOfTheEvent       <- lead department
        +-- jolux:institutionInChargeOfTheEventLevel2 <- lead office
        +-- jolux:opinionHasDraftRelatedDocument      <- consultation documents

There is no subject taxonomy on jolux:Consultation — thematic filtering is free-text over eventTitle only, and status is derived from the deadline (not the source status field).

Legislative lifecycle — where consultations sit (all in this one server):

  Vernehmlassung            Bundesblatt (BBl)          Systematische Sammlung (SR)
  (consultation)     ─────► (dispatch / act text) ───► (consolidated law in force)
  ────────────────         ─────────────────────      ───────────────────────────
  fedlex_get_open_          fedlex_search_gazette      fedlex_search_laws
    consultations           (eli/fga/…)                fedlex_get_law_by_sr
  fedlex_search_                                       fedlex_get_law_history
    consultations                                      (eli/cc/…)
  fedlex_get_consultation
        │  jolux:foreseenImpactToLegalResource
        └───────────────────────────────────────────► links a consultation forward
                                                       to the SR resource it amends

The consultation stage is the earliest public point of influence — the tools above answer what is open and until when, before a draft reaches the Bundesblatt.

schema.org — terminology (TERMDAT via LINDAS, graph fch/termdat)

<concept>  = https://register.ld.admin.ch/termdat/40109      (a schema.ld.admin.ch/Term, ValidatedEntry)
  +-- schema:name         preferred name per language (de/fr/it/en; rm effectively absent)
  +-- schema:description  multilingual definition
  +-- schema:hasPart  ->  <term> = .../termdat/40109/3/de     (synonym/variant, language + position suffix)

SPARQL endpoints: https://fedlex.data.admin.ch/sparqlendpoint · https://lindas.admin.ch/query Licence: Free reuse per fedlex.admin.ch; TERMDAT via LINDAS under open reuse.

Architecture decision

ARCH A — live SPARQL only, for all three data areas, consistent with the existing Fedlex integration (decided 2026-07-18).

Both sources are unauthenticated SPARQL endpoints with acceptable latency, so no dump/offline fallback is needed: if the Fedlex endpoint is down the server cannot function anyway, and adding a cache would only mask that. LINDAS is a separate endpoint, and its outage must not degrade the fedlex_* tools.

Isolation requirement: Fedlex and LINDAS use separate httpx clients, separate timeouts and separate error/status reporting. A LINDAS timeout cannot fail a fedlex_* call and vice versa (covered by an isolation test).

Languages

Project Structure

fedlex-mcp/
+-- src/fedlex_mcp/
|   +-- __init__.py              # Package
|   +-- server.py                # 12 tools, 2 resources (Fedlex + LINDAS)
+-- tests/
|   +-- test_server.py           # Unit tests (mocked)
+-- .github/workflows/ci.yml     # GitHub Actions (Python 3.11/3.12/3.13)
+-- pyproject.toml
+-- CHANGELOG.md
+-- CONTRIBUTING.md               # Contributing guide (English)
+-- CONTRIBUTING.de.md            # Contributing guide (German)
+-- SECURITY.md                   # Security policy (English)
+-- SECURITY.de.md                # Security policy (German)
+-- LICENSE
+-- README.md                    # This file (English)
+-- README.de.md                 # German version

Known Limitations

• SPARQL complexity: Very broad keyword searches may time out (45s timeout)
• Language coverage: German has the most complete data; other languages may have gaps
• Historical data: Not all historical versions of laws have machine-readable metadata
• Rate limiting: The endpoints may throttle high-frequency requests

Consultations — scope and reliability (read this before relying on it)

• Federal only. No cantonal consultations. Fedlex holds federal (Bund) consultations. Cantonal consultations — often the more relevant ones for a school authority (Schulamt) — are not in Fedlex and not covered here. This is a hard scope boundary, not a gap to be worked around.
• This is not a push service. MCP is pull-based: the server answers on request which consultations are open and which expire soon. It cannot notify, schedule, or alert. Recurrence comes from you or an external scheduler — never from the server. "No open consultations" means nothing is open right now, not nothing is coming.
• Thematic filtering is free-text, and imperfect. jolux:Consultation has no subject/classification taxonomy (verified live 2026-07-20) — filtering is substring search over the title only. topic="education" expands to a disclosed keyword union and deliberately over-matches (a too-narrow filter would falsely reassure); expect some false positives (e.g. "Ausbildung" inside an unrelated title) and, for niche wording, possible false negatives. The response always states which terms were searched.
• Coverage / latency: ~2,553 consultations; the historical corpus 1960–1991 sits with the Federal Archives, out of scope. Newly opened consultations appear with the upstream Fedlex publication latency (not real-time).
• Deadlines end on the calendar day in Europe/Zurich; days_remaining is computed at request time, never cached. 0 = the deadline is today.

Live findings (verified 2026-07-20):

• Quirk 1 — the deadline wins over the status field. Status /2 ("Laufend"/running) and eventEndDate are two independent signals. The server derives status from the date: past deadline ⇒ Abgeschlossen, regardless of what the source status claims — so an expired consultation is never listed as running. When the two disagree the record is marked status_conflict: true and keeps the raw label in status_source.

TERMDAT (LINDAS) — findings (verified 2026-07-18)

• Quirk 2 — reality-check discrepancy (stated plainly). The Federal Chancellery communicates roughly 400,000 TERMDAT entries. LINDAS contains 77,692. The difference is unexplained — presumably only the validated, released subset is published as Linked Data. A negative terminology hit does not mean the term is missing from TERMDAT; it only means it is not in the LINDAS subset. Every TERMDAT response carries this note so the model draws no false conclusion.
• Quirk 3 — two URI levels. Concept URIs (…/termdat/40109) carry the preferred names and the definition; term URIs with a language/position suffix (…/termdat/40109/3/de) are synonyms/variants linked via schema:hasPart. The tools accept both forms and normalise internally to the concept ID.

What this tool is not

• Not a subscription or alerting service. It does not watch, notify, e-mail, or remind. It answers when asked. Any recurring check is driven by you or an external scheduler, outside the server.
• Not a cantonal source. Federal (Bund) consultations only — see Known Limitations.
• Not legal advice. It returns public metadata and links to official documents. Deadlines and status are derived mechanically from the published data; verify anything decision-critical against the linked Fedlex page.

Related processes across the portfolio

Swiss federal legislation runs a chain, and this server covers one part of it — the pre-parliamentary consultation. The full chain is representable across three MCP servers:

Vernehmlassung  →  Botschaft  →  Parlament  →  Referendum
(consultation)     (dispatch)    (debate)      (popular vote)
   fedlex-mcp        fedlex-mcp    parlament-mcp   swiss-democracy-mcp

• Consultation (pre-parliamentary): this server — fedlex_*consultation* tools.
• Parliamentary phase: parlament-mcp — debates, motions, votes in the Federal Assembly.
• Popular vote / referendum: swiss-democracy-mcp — federal popular votes. Consultations are a distinct, earlier stage — no overlap, but the same legislative lifecycle.

Project Phase

This server is in Phase 1 (read-only). All tools are annotated readOnlyHint: true / destructiveHint: false and only ever query the public Fedlex SPARQL endpoint — there are no write, send, or filesystem capabilities.

A transition to a later phase would require an audit re-run and the human-in-the-loop controls described in the audit catalog before any write-capable tool is added.

MCP Protocol Version

This server speaks two protocol eras over the same endpoint. The client's first request on a connection decides which one applies; a later claim from the other era is refused.

Both revisions are pinned in tests/test_protocol_version.py and asserted against the installed SDK, so a Dependabot bump of mcp cannot move either one silently. The handshake ceiling is measured against a live initialize through the assembled ASGI stack, not read off a constant name.

Note that the SDK's LATEST_PROTOCOL_VERSION is an alias for the modern era, not for the handshake era — pinning against it alone would leave the era that current clients actually negotiate free to drift.

Update policy. When the gate fails, do not edit the constant blindly: read the spec changelog between the two revisions, verify the server still behaves, then move the constant, this section, README.de.md and CHANGELOG.md together.

Four consequences of the modern revision are visible in this server:

• CORS names the routing headers. Mcp-Method, Mcp-Name and Mcp-Protocol-Version ride on every streamable-HTTP request, and a browser may only send a header the server allow-lists. See CORS_ROUTING_HEADERS in server.py.
• The listing methods carry a freshness hint. tools/list, resources/list, resources/templates/list and server/discover answer with ttlMs 300000 and cacheScope public (CACHE_HINTS). resources/read deliberately does not: it returns federal law, and a client must not treat a repealed enactment as fresh for five minutes.
• No log notifications. The logging capability is deprecated as of 2026-07-28 (SEP-2577). Up to v2.0.1 every tool sent notifications/message via ctx.info()/ctx.error() — on handshake connections without ever declaring the logging capability, on modern ones as a deprecated call the SDK dropped. Observability now sits with the operator (structlog on stderr, optional OpenTelemetry); a failure reaches the caller in the tool result itself (isError: true, see below).
• serverInfo carries the package version. In 2026-07-28 the identity is stamped into the _meta of every response, not sent once at initialize. Up to v2.0.1 its version was an empty string.

Tool failures carry isError: true. The spec reports an execution error (Fedlex or LINDAS unreachable, a body that is not JSON) as a tool result with isError: true, not as a JSON-RPC error. Since 2025-11-25 arguments that violate the input schema count as execution errors too, so the model can correct its input; the SDK answers those itself before the tool runs, without an envelope — measured in both eras, and likewise for an unknown tool name. Up to v2.0.1 the server's own failures came back with isError: false, and only match_type: "error" inside the envelope said so. The envelope still travels as structuredContent; "nothing found" (match_type: "none") is a valid answer and is not flagged. Every registered tool is checked in both eras in tests/test_tool_errors.py.

Long SPARQL calls report progress. A call can take up to 45 s, and the time sits almost entirely in attempts and the back-off between them. A client that sends a progressToken receives one notifications/progress per attempt — "Anfrage an Fedlex (Versuch 1 von 3)", on a retry "Fedlex: Versuch 2 von 3 nach HTTP 503" — with no total, since none exists that would not be invented. Over streamable HTTP in 2026-07-28 the response switches to SSE for this; without a token nothing is sent. Unlike logging, server-to-client progress is not deprecated. See tests/test_progress.py.

Both eras are exercised over the wire in tests/test_modern_era.py: a session-less server/discover and tools/call through the assembled ASGI stack, and a tool call in each era that must produce neither a log notification nor an SDK deprecation warning.

Testing

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

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

Safety & Limits

• Read-only: All tools perform SPARQL SELECT queries only — no data is written, modified, or deleted on either endpoint. All 12 tools are annotated readOnlyHint: true / destructiveHint: false / idempotentHint: true.
• No personal data: Fedlex holds public law, gazettes and consultation metadata; TERMDAT holds official terminology. No personally identifiable information (PII) is processed or stored by this server.
• Rate limits: The Fedlex and LINDAS SPARQL endpoints are public services without a documented rate limit; use limit parameters conservatively (default 20, max 100). The server enforces a 45s timeout per request per endpoint and retries only transient failures.
• Endpoint isolation: Fedlex and LINDAS use separate clients and timeouts — a LINDAS outage does not affect the fedlex_* tools.
• Data freshness: Results reflect the endpoints at query time. No caching is performed by this server.
• Terms of service: Data is subject to the reuse conditions of fedlex.admin.ch — free reuse for commercial and other purposes.
• No guarantees: This server is a community project, not affiliated with the Swiss Federal Chancellery. Availability depends on the upstream SPARQL endpoint.

Changelog

See CHANGELOG.md

Contributing

See CONTRIBUTING.md

Security

See SECURITY.md for the security posture, hardening controls, and how to report a vulnerability.

License

MIT License — see LICENSE

Author

Hayal Oezkan . malkreide

Credits & Related Projects

• Fedlex: fedlex.admin.ch — Swiss Federal Chancellery
• TERMDAT / LINDAS: lindas.admin.ch — Linked Data service of the Swiss administration
• Protocol: Model Context Protocol — Anthropic / Linux Foundation
• Related: parlament-mcp — Swiss Federal Assembly (parliamentary phase)
• Related: swiss-democracy-mcp — Swiss federal popular votes (referendum phase)
• Related: swiss-cultural-heritage-mcp — Swiss cultural heritage data
• Related: zurich-opendata-mcp — City of Zurich open data
• Related: swiss-transport-mcp — Swiss public transport
• Portfolio: Swiss Public Data MCP Portfolio