@czagents/ares
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.
Install
npm install -g @czagents/ares
Usage with Claude Desktop
{
"mcpServers": {
"ares": {
"command": "npx",
"args": ["-y", "@czagents/ares"]
}
}
}
lookup_by_ico
Use it to retrieve one company’s official ARES record from its 7- or 8-digit IČO, including its identity, address, legal form, DIČ, and trade activities. Do not use it when the IČO is unknown; search by name or address first.
search_companies
Use it to find companies by a name and/or city, street, PSČ, and CZ-NACE filters; supplied filters are combined with AND. Do not use it for a known IČO, where lookup_by_ico is more precise.
{"query":"Seznam.cz","city":"Praha","pocet":10,"start":0}
search_by_address
Use it to list entities registered at a Czech street address, for example when assessing a virtual office or building concentration. Do not use it for a single known company; use lookup_by_ico instead.
{"street":"Radlická","city":"Praha","psc":15000,"pocet":20}
search_by_nace
Use it for a sector search by CZ-NACE code, optionally within one city. Do not use it to determine a specific company’s business activities; retrieve that company with lookup_by_ico.
{"nace":"62","city":"Praha","pocet":20}
get_bank_accounts
Use it to retrieve transparent accounts published in ARES for a VAT-registered subject, such as when checking invoice payment details. Do not use it to decide whether a payer is reliable for VAT purposes; use ADIS for that check.
get_statutaries
Use it to identify current, active statutory-body members who can act for a company. Do not use it as a complete ownership or historical-officer investigation.
get_owners
Use it to list the owners (společníci for s.r.o./v.o.s./k.s., akcionáři for a.s.) published in the Veřejný rejstřík, with their share (vklad/splaceno/velikost podílu) exactly as reported, plus historical owners with their date of removal. This is raw registry data only — no risk scoring or cross-company aggregation — and an empty result (most a.s. do not publish akcionáři) is not an error. Do not use it as a complete or verified ownership picture; ARES only reflects what has been filed in the public register.
validate_dic
Use it for a Czech DIČ format and checksum validation. Do not use it as proof that a subject is VAT registered or a reliable payer; it validates the identifier only.
check_vat_payer
Use it to check whether a company is registered as a VAT payer in ARES and retrieve its DIČ, tax office, and transparent accounts. Do not use it to assess the statutory “unreliable payer” flag; use ADIS for that.
get_history
Use it to retrieve available company-history data, including prior names, registered-address changes, and trade-licence history. Do not use it for the current company record alone; lookup_by_ico is the simpler choice.
watch_entity
Use it to begin onboarding for free monitoring of one company by IČO. It currently persists nothing and returns onboarding guidance; do not use it as evidence that monitoring is active or as a replacement for a current lookup.
Self-host
Source: https://github.com/martinhavel/cz-agents-mcp
git clone https://github.com/martinhavel/cz-agents-mcp
cd cz-agents-mcp
npm install
npm run build
node packages/ares/dist/index.js
Free tier & pricing
ARES itself is a free public API. The hosted endpoint at https://ares.cz-agents.dev/mcp is rate-limited per IP. Higher limits and commercial use: https://cz-agents.dev/pricing.html
License
MIT — see LICENSE