swiss-efv-mcp 0.3.0

MCP server for Swiss federal finances (EFV): budget, debt, forecasts and spending data

🇨🇭 Part of the Swiss Public Data MCP Portfolio — open-source MCP servers connecting AI agents to Swiss public and open data. This is a private project. It is independent of any employer or institutional affiliation.

🏛️ swiss-efv-mcp

MCP server for Swiss federal finances (EFV): budget, debt, forecasts and spending by task and institution.

🇩🇪 Deutsche Version

Overview

This server closes the fiscal gap in the portfolio's Economics & Finance cluster. swiss-snb-mcp already covers monetary policy; swiss-efv-mcp adds the state budget — federal revenue, expenditure, balance, debt ratios (with forecasts to 2029), a hierarchical budget drill-down, and spending by department. Data comes from the Eidgenössische Finanzverwaltung (EFV) via opendata.swiss (OGD Schweiz).

Features

• Five read-only tools over the curated EFV FS/GFS dump files.
• Headline series 1990–2029 per household (bund, ktn, gdn, staat, sv) and model (FS / GFS); every point carries is_projection so actuals and plan/forecast years are unambiguous.
• Hierarchical federal-budget drill-down and spending by department / unit.
• 24 h TTL in-memory cache with stale-serve fallback; retry with exponential backoff (2/4/8 s); dump_status never returns empty silently.
• Dual transport: stdio (local) and SSE (cloud).
• No authentication required — public open-government data (No-Auth-First).

🎯 Anchor Demo Query

"How has the federal balance developed since the SNB rate turnaround in 2022 — and which task areas absorbed the growth in spending?"

fiscal_headline(variable="saldo", household="bund", year_from=2021)
fiscal_budget_breakdown(topic="Ausgaben nach Aufgabengebiet", level=2)

Cross-read with swiss-snb-mcp, this connects the interest-rate cycle to the federal deficit — something neither server can answer alone.

Prerequisites

• Python 3.11+
• uv / uvx (recommended) or pip
• Network access to data.finance.admin.ch and efv.admin.ch — no API key needed

Installation

uvx swiss-efv-mcp            # zero-install run (once published to PyPI)
# or
pip install swiss-efv-mcp

Claude Desktop (claude_desktop_config.json):

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

Quickstart

# Run locally over stdio (default transport)
uvx swiss-efv-mcp

# From a checkout, without installing
PYTHONPATH=src python -m swiss_efv_mcp

Configuration

All configuration is loaded once into a typed Settings object (pydantic-settings). The legacy unprefixed names below keep working; the canonical names use the EFV_MCP_ prefix. Defaults are safe for local use.

Variable	Default	Purpose
TRANSPORT	stdio	Transport: stdio (Claude Desktop) or sse / streamable-http (cloud)
HOST	127.0.0.1	Bind host (SSE only). Loopback by default; set 0.0.0.0 only in a container
PORT	8000	Bind port (SSE only)
EFV_MCP_LOG_LEVEL	INFO	structlog level (JSON to stderr)
EFV_MCP_CORS_ORIGINS	[]	SSE only: explicit allowed browser origins (default-deny; comma-separated or JSON)
EFV_MCP_OTEL_ENABLED	false	Enable OpenTelemetry tracing (requires the otel extra); standard OTEL_* env vars configure export

Cloud (Render / Railway):

TRANSPORT=sse PORT=8000 swiss-efv-mcp   # exposes /sse

Available Tools

Tool	Purpose
fiscal_headline	Revenue / expenditure / balance / debt ratios over 1990–2029, per household and model; every point flags is_projection
fiscal_budget_breakdown	Hierarchical federal budget by topic (Ausgaben nach Art / nach Aufgabengebiet, Einnahmen, Bilanz, …)
fiscal_by_institution	Spending per department / administrative unit since 2007 (Personalausgaben, Informatik, external services, FTE)
fiscal_list_dimensions	Discover valid parameter values — call this first to build correct arguments
fiscal_status	Cache freshness and upstream health per dataset; never returns empty silently
dump_status	Deprecated alias of fiscal_status (kept for backward compatibility; removed in a future minor)

All tools are read-only: each is annotated readOnlyHint: true, destructiveHint: false, only issues HTTP GETs against the EFV dump files, and has no write, send, or filesystem capability.

MCP primitives. This server uses only the Tools primitive. The EFV data are sliced live from cached dumps with no stable resource hierarchy to expose as Resources, and there are no server-authored Prompts. The five tools are small and closely related, so they live in a single server.py rather than a tools/ package.

Architecture

                      ┌──────────────────────────────┐
   Claude / Agent ──▶ │  swiss-efv-mcp (FastMCP)      │
                      │  5 tools · Pydantic v2 env.   │
                      └───────────────┬──────────────┘
                                      │ fetch + retry + TTL cache
              ┌───────────────────────┴───────────────────────┐
              ▼                                               ▼
   data.finance.admin.ch                          efv.admin.ch/dam
   fs_dashboard/main_extern.csv                   bundeshaushalt_de.csv
   (headline, 1990–2029)                          institutionen_de.csv

Architecture decision

This server uses Architecture C (Dump-first).

Rationale (verified live on 2026-07-24):

• The EFV FS/GFS dashboard has no filtered query API; it serves static CSV dumps that its front-end filters in the browser.
• Three curated files are small enough to fetch-and-cache whole (516 KB / 5 MB / 1 MB). They cover the headline aggregates, the hierarchical budget and the by-institution view — i.e. the answerable questions.
• The full detail cubes (standardauswertung.csv 157 MB, fir_art_funk.csv 1.23 GB) are out of scope for v0.1.0; loading them per request is not viable. A future Phase 2 would pre-process them into SQLite/Parquet.

Consequences:

• Files are cached in memory with a 24 h TTL; stale cache is preferred over an empty response when upstream is down.
• Retry with exponential backoff on all HTTP; dump_status always returns a readable state.

Project Structure

swiss-efv-mcp/
├── src/swiss_efv_mcp/
│   ├── __init__.py
│   ├── __main__.py        # entry point; dual transport (stdio / SSE+CORS)
│   ├── client.py          # dump-first data layer: egress allow-list, retry, UA, TTL cache
│   ├── logging_config.py  # structlog JSON to stderr
│   ├── models.py          # Pydantic v2 envelopes (source + provenance)
│   ├── server.py          # 5 FastMCP tools (annotated) + testable *_impl functions
│   └── settings.py        # typed pydantic-settings config
├── tests/                 # respx mock tests + hardening tests + @pytest.mark.live
├── docs/                  # network-egress.md + accepted-risk ADRs
├── audits/                # MCP best-practice audit runs (findings, report, summary)
├── README.md · README.de.md · CHANGELOG.md · SECURITY.md · CONTRIBUTING.md
├── Dockerfile · server.json · LICENSE
└── pyproject.toml

Safety & Limits

• Read-only. Every tool is annotated readOnlyHint: true, only issues HTTP GETs against the EFV dump files, and has no write, send, or filesystem capability.
• Egress allow-list. An immutable ALLOWED_HOSTS frozenset + assert_host_allowed() is enforced before every request (HTTPS-only, two fixed EFV hosts). URLs are hardcoded constants; no user input builds a URL. See docs/network-egress.md.
• TLS on. httpx certificate verification is on by default and never disabled.
• No credentials. The endpoints are public OGD; no API keys or secrets are stored or forwarded. A browser User-Agent is injected because the endpoints 403 the default httpx/curl UA (see Known limitations) — do not remove it.
• Error masking. mask_error_details=True plus client-side masking keep raw upstream/internal detail out of tool results; full detail goes only to the structlog stderr log.
• Input bounds. Tool arguments carry explicit Pydantic constraints (year 1900–2100, level 1–8, string max_length).
• Graceful degradation. Retry with exponential backoff (2/4/8 s); a stale cache is served over an empty response; dump_status always returns a readable state and never a silent empty.
• Loopback + default-deny CORS. SSE binds to HOST, default 127.0.0.1; set HOST=0.0.0.0 only inside a container (the provided Dockerfile does). Browser origins must be listed explicitly via EFV_MCP_CORS_ORIGINS.
• Audited. Reviewed against the portfolio MCP best-practice catalogue (44 applicable checks) — see audits/ and SECURITY.md. Accepted risks are documented as ADRs under docs/adr/.
• Not authoritative. Figures are not official; consult the EFV originals for official use.

Known limitations

Live-probe findings (2026-07-24), also in CHANGELOG.md → Known findings:

Finding	Impact
Endpoints return HTTP 403 without a browser User-Agent	UA is injected by the client; do not remove it
opendata.swiss "CSV" links for 2 datasets point to an HTML landing page	real files resolved to a DAM path (/dam/de/sd-web/{id}/…) whose opaque id may rotate on re-upload
NA appears as a literal string in hh/model/source	cleaned to None centrally
"Forward-looking" is not one label: Bund uses "Budget/financial plans", staat uses "Forecasts"	abstracted via is_projection
Accounting-model break at 2022/2023 ("bis 2022" vs "ab 2023" topics)	series has a seam; a note flags affected topics
Detail cubes (157 MB / 1.23 GB) not served	Phase 2; use the curated files for now

Project Phase

This server is in Phase 1 (read-only). Every tool only ever fetches the public EFV dump files — there are no write, send, or filesystem capabilities.

Phase	Scope	Status
1 — Read-only	Headline series, budget breakdown, spending by institution	✅ current
2 — Detail cubes	Pre-process the 157 MB / 1.23 GB cubes to SQLite/Parquet	planned
3 — Multi-agent	(none planned)	—

A transition to a later phase would require a re-audit before any write-capable tool is added.

MCP Protocol Version

The protocol version is negotiated at the initialize handshake by FastMCP (pinned fastmcp>=3.4 in pyproject.toml), which builds on the mcp Python SDK. The baseline this server is built and audited against is 2025-11-25, pinned as MCP_PROTOCOL_VERSION in server.py; a regression test asserts the negotiated version still equals it, so a protocol-changing SDK bump fails CI loudly (ARCH-012). Dependencies are kept current via monthly Dependabot PRs (.github/dependabot.yml); protocol-relevant bumps are noted in CHANGELOG.md.

Testing

PYTHONPATH=src pytest tests/ -m "not live"   # offline, respx-mocked
PYTHONPATH=src pytest tests/ -m live         # hits the real EFV endpoints
PYTHONPATH=src ruff check src tests

Changelog

See CHANGELOG.md.

Security

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

Contributing

Issues and pull requests are welcome. Please keep tools read-only, run ruff check and the offline test suite before submitting, and add a CHANGELOG.md entry under [Unreleased] for user-facing changes. See CONTRIBUTING.md.

Maintainers: see PUBLISHING.md for the step-by-step PyPI release process (Trusted Publishing via GitHub Release).

License

MIT for this server — see LICENSE. The EFV data remain subject to the OGD Schweiz terms (freely usable, with attribution).

Author

Hayal Oezkan · github.com/malkreide

Credits & Related Projects

• Data: Eidgenössische Finanzverwaltung EFV via opendata.swiss (OGD Schweiz, freely usable)
• Companion: swiss-snb-mcp (monetary policy) — the fiscal/monetary pair
• Portfolio index: swiss-public-data-mcp

Disclaimer: private project, independent of any employer or institution. No warranty; figures are not authoritative — consult the EFV originals for official use.