bartosz-kuc/honest-vies-mcp

Local MCP server for the **EU VIES VAT number validator** (the authoritative EU-wide check used before issuing 0% VAT cross-border invoices) — no authentication, no rate limit, no cloud middle.
Part of the honest-mcp family of small, auditable, local-first MCP servers.
Why
A Polish JDG (or any EU business) issuing a **0% VAT reverse-charge invoice** to an EU B2B customer must first verify that customer's VAT number is registered in VIES — and keep evidence of the check. Skipping this and it turns out the customer's VAT is invalid, your tax office will demand domestic VAT from **you** (23% in Poland), retroactively, plus interest.
This server puts VIES a single tool call away. Ask your AI "verify DE143454214 before I issue this invoice" and you get: valid/invalid, registered name and address, and a consultation number for your records if you provided your own VAT.
Same trust model as the rest of the family: data flows only between your machine and the European Commission.
Features
Two tools:
- check_vat — validate a single EU VAT number. Optionally pass your own VAT (requester_country + requester_vat) to receive a consultation number as legal proof of the check.
- list_supported_countries — the 27 EU country codes + XI for Northern Ireland.
Data source
- Endpoint: ec.europa.eu/taxation_customs/vies/ REST API
- No API key, no registration
- Coverage: 27 EU member states + Northern Ireland (XI)
- Note: Greece uses country code EL, not GR
Requirements
- Python 3.10+
Setup
On Windows, create the venv with python -m venv venv and use venv\Scripts\pip and venv\Scripts\python.exe instead of the venv/bin/... paths shown here and below.
Register with Claude Code:
Claude Desktop claude_desktop_config.json:
Example usage
> "Verify German VAT DE143454214 before I invoice them."
check_vat(country_code="DE", vat_number="143454214") → valid/invalid + name/address.
> "Verify the same, but also get a consultation number — my VAT is PL7393933151."
check_vat(vat="DE143454214", requester_country="PL", requester_vat="7393933151") → response includes a consultation_number field. Save that number with the invoice.
> "What's the EU VAT country code for Greece again?"
list_supported_countries() → confirms Greece is EL, not GR.
Data flow
No cloud middle. Nothing to log in to. No telemetry.
For Polish JDG owners
The tax law bit: **art. 42 ust. 1 pkt 1 ustawy o VAT** — before applying the 0% rate on an intra-community supply (WDT), the seller must have a valid VAT-UE number of the buyer. **Art. 100 ust. 8 pkt 1** — proof of the check is expected on audit. The consultation_number (VIES's requestIdentifier) is the standard evidence: it's a unique code tying your check to a specific date and pair of VAT numbers. Store it with the invoice.
Non-obvious bits VIES will bite you with:
- If your OWN VAT (the requester) is not currently active in VIES, no consultation number is returned even when the checked VAT is valid.