ares

Czech & Slovak business registry — look up companies by IČO, search by name, check legal form, address, and VAT status.

CommunityOnlineNo sign-inGlobalFreeRead-only

What it can do

  • Lookup By Ico: Get a single Czech company record by its IČO (8-digit Business ID). Returns official name, registered address, legal form, VAT ID (DIČ), founding date, and trade license activities. Ret
  • Search Companies: Search ARES by company name, city, street, PSČ, or NACE code. Combines all filters with AND. Useful when user knows name but not IČO, looking for companies in a building, or all busi
  • Search By Address: Find all companies registered at a given Czech address. Useful for due diligence (virtual offices, shell companies), real estate research, or competitor mapping in a building.

What data it sees

Do you need an account

No: the server works without sign-in

Czech & Slovak business registry — look up companies by IČO, search by name, check legal form, address, and VAT status. Direct from ARES (Czech Ministry of Finance), the official source. Fast, free, no reseller markup.

How to connect

How to connect ares to Claude

The server address to paste into Claude settings:

https://cz-agents-ares--martin-havel.run.tools

  1. Open Claude (claude.ai or the desktop app).
  2. Go to Settings → Connectors.
  3. Click Add custom connector.
  4. Paste the server address copied below into Remote MCP server URL and click Add.
  5. In a chat, click + → Connectors and switch the new connector on.

Custom connectors are available on Free, Pro, Max, Team and Enterprise plans (Free is limited to one). On Team and Enterprise an organization Owner adds the connector first under Organization settings → Connectors.

Authorization

After you click Add, a sign-in window for the service opens. Sign in with your own account and approve access. Claude never sees your password.

How to connect ares to ChatGPT

The server address to paste into ChatGPT settings:

https://cz-agents-ares--martin-havel.run.tools

  1. Open ChatGPT in a browser (chatgpt.com). A Plus, Pro, Business, Enterprise or Edu plan is required.
  2. Turn on developer mode once: Settings → Apps → Advanced settings → Developer mode.
  3. Open Settings → Connectors and click Create.
  4. Fill in the form: Name (anything), Description (one line about what the service does), MCP server URL (copy it below).
  5. Under Authentication choose OAuth if the service requires sign-in, otherwise None. Click Create.
  6. In a new chat open + → Apps/Connectors and enable the connector.

OpenAI has renamed this section before (Connectors → Apps/Plugins). If the label differs, search settings for "developer mode". On Business/Enterprise workspaces an admin must allow custom connectors first.

Authorization

On first use ChatGPT opens the service's sign-in window. Sign in and approve access.

How to connect ares to Cursor

The server address to paste into Cursor settings:

https://cz-agents-ares--martin-havel.run.tools

Fastest: click Open in Cursor below and confirm the prompt.

Manually:

  1. In Cursor open Settings → Cursor Settings → MCP and click Add new global MCP server.
  2. Paste the JSON copied below into ~/.cursor/mcp.json (per project: .cursor/mcp.json in the repo root).
  3. Save the file. The server appears in the MCP list; authorize it there if asked.

Authorization

If the service needs sign-in, an authorize button appears next to the server in the MCP list.

Server tool list (9)

Raw names from tools/list. Only developers need these.

lookup_by_icoGet a single Czech company record by its IČO (8-digit Business ID). Returns official name, registered address, legal form, VAT ID (DIČ), founding date, and trade license activities. Returns null if IČO is not found in ARES.
search_companiesSearch ARES by company name, city, street, PSČ, or NACE code. Combines all filters with AND. Useful when user knows name but not IČO, looking for companies in a building, or all businesses in a sector.
search_by_addressFind all companies registered at a given Czech address. Useful for due diligence (virtual offices, shell companies), real estate research, or competitor mapping in a building.
search_by_naceFind Czech companies by CZ-NACE activity code (economic sector classification). Example: "62" = IT, "47" = retail, "86" = healthcare. Optional city filter. Useful for market research.
get_bank_accountsGet transparent bank accounts published for this company (only available for VAT-registered subjects). Useful to verify payment details on an invoice match the company.
get_statutariesGet current statutory body (jednatelé, představenstvo, etc.) of a Czech company — who can legally act on its behalf. Returns active members only (with valid zápis, not yet removed). Essential for due diligence and compliance checks.
validate_dicValidate a Czech DIČ (VAT ID). Format check: "CZ" + 8-10 digits. For 8-digit tail (legal entities) also runs MOD11 checksum against the embedded IČO.
check_vat_payerCheck whether a Czech company is a registered VAT payer (plátce DPH). If yes, returns DIČ, financial office, and any transparent bank accounts (payment details).
get_historyGet historical record of a company (previous names, registered address changes, trade license history). Useful for due diligence.