registry-mcp

registry-mcp — the company registry MCP

Company data for AI agents, any country. One MCP server and REST API, two national registers today: Norway's Enhetsregisteret / Brønnøysundregistrene (brreg), looked up by organisasjonsnummer (orgnr), and the United Kingdom's Companies House, looked up by company number — one JSON shape either way.

claude mcp add registry-mcp --transport http https://api.foretak.dev/mcp

No install step, over stdio:

claude mcp add registry-mcp -- uvx registry-mcp

What makes it worth a tool slot:

• Deadlines that cite the rule, not just a date. company_deadlines gives the next filing date and names why in applies_because — a Norwegian legal form's statutory duty, or "Companies House publishes this date for the company itself" when the register states it rather than us computing it. Quote the reason, not just the number.
• Never more than 24 hours stale, and it says so. Every response carries cached and fetched_at. OpenCorporates' own knowledge base tells users to "allow 30 days" for a correction to reach its site — a 30× freshness gap, stated by the incumbent about itself.
• Seven tools, not fifty — five registry tools plus two ChatGPT connector aliases. Tool-selection accuracy degrades past 30-50 tools loaded into an agent's context, and some clients cap around 40. Seven tools is roughly 17% of that budget, next to competitors in this space shipping 23 to 78 tools for the same job.

Security. Read-only, always — nothing here writes to a register or anywhere else. No credentials are required from a caller; this deployment's own upstream credential (COMPANIES_HOUSE_API_KEY) is read from the environment and never logged or returned. Two named upstreams, and nothing else is ever called: data.brreg.no and api.company-information.service.gov.uk. No personal data beyond what each national register already publishes about the entity itself. This service does not perform sanctions, PEP or adverse-media screening, and it does not verify bank account details. Details: SECURITY.md.

One-click install, for a remote streamable-HTTP server:

Other clients (Claude Desktop, Cursor, VS Code, Cline, plain JSON configs): see docs/clients.md.

Add to ChatGPT

ChatGPT reaches an MCP server through a custom connector, and its deep research mode calls exactly two tools — search and fetch — which this server ships alongside the five registry tools. In ChatGPT, open Settings → Connectors, add a custom connector, and give it:

https://api.foretak.dev/mcp

No authentication, no key, no account. If your ChatGPT plan does not show custom connectors under Settings → Connectors, turn on Settings → Security and login → Developer mode first, then add the URL from https://chatgpt.com/plugins.

search takes one free-text query — a company name, a national identifier, or a name plus a country ("Tesco United Kingdom") — and returns citable rows; fetch takes a row's id ("NO:923609016") and returns that company's register record and its statutory filing deadlines, with the full JSON of both in metadata.

Add to Claude Desktop

Claude Desktop takes the same URL as a custom connector: Settings → Connectors → Add custom connector, then https://api.foretak.dev/mcp. No key. For a local stdio install instead, see Configuration.

Status: 0.2.0. The five registry tools and their response shapes are frozen; two connector aliases (search, fetch) wrap them for ChatGPT and add no new shape. The hosted API at api.foretak.dev is live, and listed in the official MCP registry as io.github.foretak/registry-mcp. Countries: Norway (brreg), United Kingdom (Companies House) — see below for both countries' identifier formats and example calls.

Add to Claude Code

The same two commands as above — Streamable HTTP or local stdio. To add it as a project-level .mcp.json file instead of the CLI, see Configuration.

What it returns

$ curl https://api.foretak.dev/v1/NO/company/923609016
{
  "country": "NO", "registry": "brreg",
  "id": "923609016", "id_formatted": "923 609 016", "id_scheme": "organisasjonsnummer",
  "name": "EQUINOR ASA",
  "legal_form_code": "ASA", "legal_form": "Public limited company", "legal_form_local": "Allmennaksjeselskap",
  "status": "active", "is_active": true, "registered_at": "1995-03-12",
  "vat_registered": true, "vat_number": "NO923609016MVA", "vat_registered_at": "1989-07-01",
  "employees": 21239, "share_capital": 5976872600.0, "share_capital_currency": "NOK",
  "business_address": {"lines": ["Forusbeen 50"], "postal_code": "4035", "city": "STAVANGER"},
  "source": "Enhetsregisteret (Brønnøysundregistrene)", "license": "NLOD 2.0"
}

Abridged — the full CompanyReport also carries previous_names, industry_codes, registers, purpose, parent_id, confidence, cached, fetched_at and notes. Every field is documented in llms-full.txt §5.

The United Kingdom, same shape, same abridgement:

$ curl https://api.foretak.dev/v1/GB/company/00445790
{
  "country": "GB", "registry": "companies-house",
  "id": "00445790", "id_formatted": null, "id_scheme": "company number",
  "name": "TESCO PLC",
  "legal_form_code": "plc", "legal_form": "Public limited company",
  "status": "active", "is_active": true, "registered_at": "1947-11-27",
  "vat_registered": null, "vat_number": null,
  "employees": null, "employees_reported": false,
  "registers": {"charges": false, "insolvency": false},
  "industry_codes": [{"code": "47110", "description": null, "scheme": "SIC 2007", "rank": 1}],
  "business_address": {"lines": ["Tesco House, Shire Park", "Kestrel Way"], "postal_code": "AL7 1GA", "city": "Welwyn Garden City"},
  "published_deadlines": [
    {"kind": "annual_accounts", "due_date": "2027-08-26", "period_end": "2027-02-26", "overdue": false, "source": "accounts.next_accounts.due_on"},
    {"kind": "confirmation_statement", "due_date": "2027-07-02", "period_end": "2027-06-18", "overdue": false, "source": "confirmation_statement.next_due"}
  ],
  "source": "Companies House (UK)", "license": "Crown copyright — Companies House public register, free to re-use"
}

published_deadlines carries the dates the register publishes itself, with the upstream field each came from. It is [] for Norway, which computes all of its own.

Note the nulls. Companies House publishes no VAT status, no employee count and no share capital for any company, so those fields are null rather than guessed — null means "this register does not say", never "no". That honesty is the point of one shape across countries.

And the deadlines, which is where the UK module earns its keep:

$ curl "https://api.foretak.dev/v1/GB/company/00445790/deadlines?today=2026-09-04"
{
  "company_name": "TESCO PLC", "today": "2026-09-04",
  "deadlines": [
    {"kind": "confirmation_statement", "local_name": "Confirmation statement (CS01)",
     "due_date": "2027-07-02", "period_end": "2027-06-18", "days_until": 301,
     "applies_because": "Companies House publishes this date for the company itself; it is the register's own figure, not a calculation."},
    {"kind": "annual_accounts", "local_name": "Annual accounts",
     "due_date": "2027-08-26", "period_end": "2027-02-26", "days_until": 356,
     "applies_because": "Companies House publishes this date for the company itself; it is the register's own figure, not a calculation."}
  ]
}

Where Companies House publishes a date, it is quoted; where it does not, the date is computed from a cited statute and applies_because says so. UK deadlines never roll forward off a weekend or bank holiday, and days_until goes negative for a filing the register still shows as overdue.

Tools

Connector aliases — for ChatGPT, which reaches an MCP server through exactly search and fetch (Add to ChatGPT); add no new response shape and have no REST twin.

Plus the resource registry://rules/{country} (identifier rules, legal forms, deadline rules — read once instead of validating in a loop) and the prompt explain_company.

parent_id and in_group on a Norwegian CompanyReport describe Enhetsregisteret's own parent/sub-unit relation for that entity — nothing more. There is no group-walk tool: following a corporate group upward means calling lookup_company again on parent_id, repeatedly, and that walk answers "what does the register list as this entity's parent?", not "who beneficially owns or controls this company?" — a different question this service does not answer. See llms-full.txt §5.

Why an agent checks a company

Three rules make this a duty rather than a nicety. Finanstilsynet's Rundskriv 15/2019 § 4.4.1 accepts an oppslag against Enhetsregisteret no older than three months, one month where the check rests on company details the customer supplied, and asks for notoritet about the lookup: what was consulted, and when. From 1 January 2027 Norwegian bookkeeping-obliged businesses must invoice each other by e-invoice, and the receiver is resolved in ELMA as 0192: plus organisasjonsnummer, the identifier these tools already take. From 10 July 2027, AMLR Article 23(4) requires "valid proof of registration or a recently issued excerpt of the register" for every new business relationship with a legal entity.

That is what source_url, fetched_at, cached, license and applies_because are for: which record was consulted, when it was read, whether it came from the 24 h cache, the terms it travels under, and whether a deadline was quoted from the register or computed from a named rule.

The limits, stated rather than implied: no sanctions or PEP screening; no bank-account verification, and the commonest invoice fraud is payment redirection, where the supplier is real and only the account number is wrong; and no beneficial owners, which brreg releases on application only, to categories of applicant that do not include a product vendor. Fuller version in llms-full.txt §9.

Configuration

{
  "mcpServers": {
    "registry-mcp": {
      "command": "uvx",
      "args": ["registry-mcp"],
      "env": {
        "REGISTRY_MCP_CONTACT_EMAIL": "you@example.com",
        "COMPANIES_HOUSE_API_KEY": "your-companies-house-key"
      }
    }
  }
}

{
  "mcpServers": {
    "registry-mcp": {
      "command": "uvx",
      "args": ["registry-mcp"],
      "env": { "REGISTRY_MCP_CONTACT_EMAIL": "you@example.com" }
    }
  }
}

{
  "mcpServers": {
    "registry-mcp": {
      "command": "uvx",
      "args": ["registry-mcp"],
      "env": { "REGISTRY_MCP_CONTACT_EMAIL": "you@example.com" }
    }
  }
}

{
  "mcpServers": {
    "registry-mcp": { "command": "npx", "args": ["-y", "registry-mcp"] }
  }
}

{
  "mcpServers": {
    "registry-mcp": { "type": "http", "url": "https://api.foretak.dev/mcp" }
  }
}

Environment variables — all optional:

REST

Every tool has a REST twin returning the identical JSON document.

# One company by organisasjonsnummer
curl https://api.foretak.dev/v1/NO/company/923609016

# Search by name
curl "https://api.foretak.dev/v1/NO/search?q=equinor&limit=5"

# Statutory filing deadlines, from a date you choose
curl "https://api.foretak.dev/v1/NO/company/923609016/deadlines?today=2026-01-15"

# Checksum-validate an identifier — no upstream call, instant
curl https://api.foretak.dev/v1/NO/validate/923609016

# Which countries are live, and which need an API key
curl https://api.foretak.dev/v1/countries

# The same five routes for the United Kingdom — GB, never UK
curl https://api.foretak.dev/v1/GB/company/00445790
curl "https://api.foretak.dev/v1/GB/search?q=tesco&limit=5"
curl "https://api.foretak.dev/v1/GB/company/00445790/deadlines?today=2026-09-04"
curl https://api.foretak.dev/v1/GB/validate/445790

Machine-readable docs: /llms.txt, /llms-full.txt, /openapi.json.

Adding your country

Norway is one folder. So is the United Kingdom: registries/gb/ was added as four files and one import line, and GB appeared in list_countries, in every tool, in /openapi.json and in registry://rules/GB on its own.

Copy src/registry_mcp/registries/xx/ to registries/<cc>/, implement four methods, add one import line — nothing in core/ changes, and both surfaces plus the manifests light up for the new country automatically.

→ CONTRIBUTING.md — "Add your country", and the new country issue template to claim one first.

Development

uv sync --all-extras
uv run pytest          # `-m "not live"` to skip the tests that hit the real registry
uv run mypy .
uv run ruff check .

Layout:

src/registry_mcp/core/        country-neutral models, Registry ABC, rules, date helpers
src/registry_mcp/registries/  one folder per country — no/ (Norway), gb/ (UK), xx/ (template)
src/registry_mcp/api/         FastAPI REST surface
src/registry_mcp/mcp/         FastMCP server (stdio + Streamable HTTP at /mcp)

Documents

• NORBIZ_SPEC.md — technical spec of the Norwegian module
• UK_SPEC.md — technical spec of the UK module
• DECISIONS.md — interface and schema decisions
• KEYWORDS.md — the canonical alias list
• SUBMISSIONS.md — registry submission status
• legal/terms.md — terms of use and data attribution

Data source and licence

Norwegian data comes from Enhetsregisteret (Brønnøysundregistrene), published under NLOD 2.0 — attribution required. UK data comes from the Companies House public register, Crown copyright, free to re-use with no attribution condition; we cite it anyway. Every response carries source, source_url and license so the attribution travels with the data. This project's own code is MIT licensed. Not affiliated with or endorsed by Brønnøysundregistrene or Companies House.