EU Business Check in ChatGPT
VAT numbers, LEIs, registries. The MCP server is https://eubusiness.openkrill.app/mcp. No key. The steps below are only for ChatGPT. A call to check_vat_number was checked against that server on 2026-10-01.
What this server answers
Check a European business before you pay or sign. Ask "is DE 811128135 a valid VAT number?", "what is the LEI of Siemens AG?" or "find the registered company called Equinor in Norway".
EU Business Check asks the official sources directly: the European Commission's VIES service for VAT numbers, the GLEIF Global LEI Index for Legal Entity Identifiers, and two national registers, the French Sirene register (through the api.gouv.fr company search) and the Norwegian Enhetsregisteret.
A VAT check says whether a number is registered for VAT in an EU member state or Northern Ireland on the day of the check. When the registered name and address are published they are shown, but only for legal entities: a name without a legal-form marker such as GmbH, SA, SRL or Limited could be a private person, so it is withheld. Some countries, such as Germany and Spain, do not publish a name at all. If you give your own VAT number, VIES also issues a consultation number that proves the check was made.
LEI and registry results show the legal name, status, legal form, registration number, address and, where published, activity and size. Sole proprietors are left out of every result because they are registered under a private person's name.
It reads only these public registers. It does not rate a company's credit, solvency or reputation, does not cover other countries' registers, and a register can lag behind a change by days. Always check an important detail on the register itself.
It stores nothing about you: answers are cached for up to an hour, except a check that asks for a consultation number, and the only lasting record is a daily count of calls per tool.
What it can do
- Checks whether an EU or Northern Ireland VAT number is valid and shows the name of a legal entity
- Issues a VIES consultation number when given the requester's own VAT number
- Finds the Legal Entity Identifier (LEI) of a company by name, or looks a LEI up
- Searches the French (Sirene) and Norwegian company registers by name or number
- Leaves out sole proprietors and withholds names that could be a private person
Tools
check_vat_number, Check an EU VAT number. Use this when the user asks whether a VAT number is valid or whom it belongs to, for example "is DE 811128135 a valid VAT number?", "check the VAT number on this invoice, ATU33864707" or "I need a VIES consultation number for this supplier". Pass the country code and the VAT number, and requesterCountry with requesterVatNumber only when the user gives their own VAT number for a consultation number. Returns whether the number is registered for VAT on the date of the check and, for a legal entity where the member state publishes it, the registered name and address; a name that could be a private person is withheld. Covers EU member states and Northern Ireland (XI), not GB. Do not use it for a person's tax or identity checks, for VAT rates, or to judge whether a business is trustworthy.find_company_lei, Find a company's LEI. Use this when the user asks for the Legal Entity Identifier (LEI) of a company or wants to look up a LEI, for example "what is the LEI of Siemens AG?", "whose LEI is W38RGI023J3WT1HWRP32?" or "is the LEI of this German company still active?". Pass the company name (and a country code to narrow it) or the 20-character LEI. Returns each entity's LEI, legal name, status, legal form code, country and city, national registration number and the LEI's renewal dates. Sole proprietors are left out. Do not use it to find a private person, for companies that have no LEI (most small businesses), or for financial or credit information.lookup_company_registry, Look up a French or Norwegian company. Use this when the user asks about a company registered in France or Norway, for example "find the French company Danone", "who is behind SIREN 552032534?" or "look up Equinor in the Norwegian business register". Pass country FR or NO and the company name or its registration number (SIREN for France, organisation number for Norway). Returns the legal name, registration number, legal form, status (active, ceased, bankrupt, being wound up), registration date, registered address, activity code and, where published, size or employee count. Sole proprietors are left out. Do not use it for other countries, for owners, directors or any private person, or for accounts and credit ratings.
Add EU Business Check in ChatGPT
ChatGPT does not read a local config file. A custom MCP server is added in the product, and only after developer mode is on. These steps were checked against OpenAI's plugin connect guide and the ChatGPT MCP guide on 2026-10-01. Developer mode can be hidden by a workspace policy, so a Team or Enterprise admin may have to allow it first.
- Open ChatGPT settings, then Security and login, and turn on Developer mode.
- Open ChatGPT plugins and select the plus button.
- Enter a name such as "EU Business Check" and a one-line description of what you want it to answer.
- Under Connection, choose the public endpoint and paste
https://eubusiness.openkrill.app/mcp. Include the/mcppath. Do not add a tunnel id: this server is already public. - Create the connection and review the tools ChatGPT lists. You should see
check_vat_number,find_company_lei,lookup_company_registry. The feedback tools on the same server are optional and not required for the lookup. - Start a new conversation, add the connection from the tools menu, and ask: Is the Austrian VAT number ATU33864707 valid, and who is it registered to?
No API key and no OAuth client id are required. The server answers without a login. Calls are limited per network and per day, and a limit comes back as a tool error rather than a partial answer. If the tool list is stale after a server change, open the connection and select Refresh, then start a new conversation.
The ChatGPT desktop app, Codex CLI and IDE extension share a different config. In the desktop app, open Settings, then MCP servers, choose Add server, select Streamable HTTP, and paste the same URL. In ~/.codex/config.toml the equivalent is a table named mcp_servers.eu-business with url = "https://eubusiness.openkrill.app/mcp". ChatGPT on the web does not read that file. A published directory listing is also a different path: this page is the developer-mode connection, not a claim that EU Business Check is already in the ChatGPT directory.
Treat the server as untrusted until you have read a few answers. A remote MCP server sees the arguments the model sends. EU Business Check is read-only and documents what it sends onward on the privacy page.
A call checked on 2026-10-01
ATU33864707 is the public example in the plugin's starter prompts. No requester VAT number is sent. The request below was posted to https://eubusiness.openkrill.app/mcp as tools/call. HTTP 200. Source: the EU Business Check server, read 2026-10-01.
{
"method": "tools/call",
"params": {
"name": "check_vat_number",
"arguments": {
"country": "AT",
"vatNumber": "U33864707"
}
}
}- source. European Commission VIES (VAT Information Exchange System)
- country. AT
- name. Red Bull GmbH
- notice. A valid result means the number is registered for VAT in that member state, as the member state's own register reports it on the date shown. It does not say the business is trustworthy, solvent or the one a person is dea
Repeat the call yourself if you need a newer reading. Cached answers expire. A rate limit is not a result: wait and try again. Nothing in the call is a ranking, a filing, or advice.