Validate EU VAT Numbers in Claude Desktop, Cursor, and ChatGPT — Official MCP Server

Originally published at

[vatnode.dev]. The version on vatnode.dev is the canonical source — refer to it for the latest content.

Your AI assistant can now check if a VAT number is real, pull the registered company name, and look up VAT rates for every EU country — all without leaving the chat. We just released vatnode-mcp, the official Model Context Protocol (MCP) server for vatnode.

This post covers what MCP is in 30 seconds, how to install the vatnode server in Claude Desktop / Cursor / ChatGPT, and a few concrete examples of why this is useful for anyone doing EU B2B work.

Model Context Protocol is an open standard from Anthropic for connecting AI assistants to external tools and data sources. An MCP server exposes a small set of tools — named functions with described inputs — and the AI model picks the right one based on what the user is asking.

Think of it as the "USB-C of AI integrations": write one MCP server and any compatible client (Claude Desktop, Cursor, ChatGPT's custom-connectors, Cline, Continue, and more) can use it. The user just edits a config file once — no per-app integration work.

vatnode-mcp

ships five tools, four of them fully offline and free:

get_country_vat_rates

list_eu_vat_rates

check_vat_format

list_supported_countries

validate_vat_number

Why four free tools? Because the data is bundled into the package via eu-vat-rates-data (also open source) — there's nothing to charge for. The paid tool is the one that calls real VIES infrastructure.

One config file edit. Open claude_desktop_config.json

(on macOS: ~/Library/Application Support/Claude/

) and add:

{
  "mcpServers": {
    "vatnode": {
      "command": "npx",
      "args": ["-y", "vatnode-mcp"],
      "env": {
        "VATNODE_API_KEY": "vat_live_..."
      }
    }
  }
}

Restart Claude Desktop. That's it. The vatnode tools appear in the tool picker. For Cursor, paste the same JSON in Settings → MCP → Add new server. ChatGPT custom connectors and other MCP clients (Continue, Cline) follow the same pattern.

The VATNODE_API_KEY

is optional — without it you still get all four free tools. To enable live VIES validation, grab a free API key (no credit card; the free tier includes a monthly request quota).

A few real example exchanges (you don't have to name the tool — Claude picks it from the description):

You:What's the standard VAT rate in Finland and Germany?

(Claude callsget_country_vat_rates

for FI and DE — free, no key needed.)

Claude:Finland's standard VAT rate is 25.5% (raised from 24% in September 2024). Germany's is 19%. Finland also has reduced rates of 13.5% and 10%; Germany has 7%.

You:Is IE6388047V a valid VAT?

(Claude callsvalidate_vat_number

— uses your API key.)

Claude:Yes, IE6388047V is valid. It belongs toGOOGLE IRELAND LIMITED, registered at Gordon House, Barrow Street, Dublin 4, Ireland.

You:I have a list of 12 European customers. Tell me which countries have reduced VAT rates for restaurant services.

(Claude callslist_eu_vat_rates

, processes the result and answers in context.)

Claude:France (10% reduced), Spain (10%), Italy (10%), Portugal (13% intermediate)... [the model interprets the data for the user's actual question]

The point isn't that Claude does VAT lookup faster than a Google search. It's that the result lands in the same conversation where you're drafting an invoice, double-checking a supplier, or writing checkout code — no context switch.

Third-party MCP marketplaces sometimes ship VAT-validation wrappers built around our public API. Using vatnode-mcp

directly is the only way to:

The current release ships five tools. Coming soon: bulk_validate

for processing lists in one call, subscribe_to_vat_changes

for monitoring (so the agent can warn you if a known-good VAT later de-registers), and a vies_consultation_number

tool that returns the audit token VIES issues when a requester VAT is configured.

If you have a specific use case the current tools don't cover, open an issue on GitHub — tool descriptions are tuned based on what people actually try, so feedback directly shapes the next release.

Try it now #

[Sign up]for a free vatnode account (optional — needed only for live VIES validation)- Paste the config block above into your claude_desktop_config.json

• Restart Claude Desktop and ask it a VAT question Full docs:

[vatnode.dev/docs/mcp]