Startup Name Check MCP in Claude: Install Guide, Live Test

Questions it answers

Check whether the domain for a startup, product or business name is already registered before you fall in love with it.

Ask "is acme.com available?", "check if this startup name is taken" or "find an available .com for my bakery name".

Startup Name Check turns a name into a domain label, then asks Cloudflare Registrar's domain-check API whether that domain can be registered and what it costs. When that API is not configured, or does not cover the ending, it asks the registry's public RDAP service instead.

It checks up to five names or domains at a time across .com, .net, .org, .ai, .app and .dev by default, or the endings you choose.

For a taken domain it shows the registration, expiry and last-change dates when the registry publishes them. It never returns who owns it or any contact details.

When Cloudflare Registrar answers for an available domain, the answer includes the registration and renewal cost. That figure is not a charge and does not reserve the name.

Results are indicative: they show the status at that moment and do not reserve a name. Premium or reserved names can be unavailable or cost more.

Trademarks are not searched, so run a trademark check before you commit to a name.

It stores nothing about you: answers are cached for up to five minutes, and the only lasting record is a daily count of calls per tool.

Short questions this server answers, each with a direct answer: Check if a startup name's domain is taken.

What it can do

Checks whether a name's domain is registered in .com, .net, .org, .ai, .app and .dev
Checks a full domain such as acme.com on its own
Compares up to five candidate names in one answer
Shows registration and expiry dates for domains that are taken, when the registry publishes them
Shows the registration and renewal cost when Cloudflare Registrar returns one
Never returns owner or contact details

Tools

check_domain_availability, Check name and domain availability. Use this when the user asks whether a domain or startup name is available or taken, for example "is acme.com available", "check if this startup name is taken" or "find an available .com for my bakery name". Pass up to 5 names or full domains. Names are checked across .com, .net, .org, .ai, .app and .dev unless tlds says otherwise. Returns, for each domain, available, registered (with registration, expiry and last-change dates when published), unsupported or unavailable, plus source. An available domain includes registrationCost and renewalCost when Cloudflare Registrar returns them. The result is indicative, not a reservation or a charge; it never includes owner details and does not check trademarks.

Add Startup Name Check in Claude

Claude connects to a remote MCP server as a custom connector. The connection is made from Anthropic's cloud, not from your laptop, so the server must be on the public internet. Startup Name Check is. These steps were checked against Claude's custom-connector article (updated 2026-08-11) and the Claude Code MCP docs on 2026-10-01.

On a Pro or Max plan:

Open Customize, then Connectors.
Select the plus button, then Add custom connector.
Paste this URL. Leave Advanced settings empty: this server does not need an OAuth client id or secret.
```
https://names.openkrill.app/mcp
```
Select Add. The connector is yours. Anthropic has not reviewed it, and it is not a Directory listing.
In a conversation, open the plus button, then Connectors, and enable Startup Name Check. Ask: Is acme.com available?

On Team and Enterprise, an Owner adds the connector first at Organization settings, then Connectors, then Add, then Custom, then Web, and pastes the same URL. Members then connect it from Customize. A Free plan can add one custom connector.

In Claude Code, add it from the project directory:

claude mcp add --transport http names https://names.openkrill.app/mcp

That writes a local or user config. A JSON entry needs "type": "http" (or streamable-http) plus the url. An entry with a url and no type is skipped. Confirm with claude mcp get names. The tools you should see are check_domain_availability.

If Claude tries to fetch https://names.openkrill.app/mcp from its code sandbox and reports HTTP 403, the block is Claude's sandbox network allowlist, not this server. The sandbox proxy answers 403 with x-deny-reason: host_not_allowed for every host outside the allowlist. Use the connector above instead: connector calls come from Anthropic's cloud and do not pass the sandbox proxy. To let the sandbox reach it as well, an Owner adds names.openkrill.app under Settings, then Capabilities, then Additional allowed domains.

Enable the connector only in conversations that need it. Claude can call the tools while you work, including during research, so turn off any tool you do not want invoked. Startup Name Check does not write to your accounts. It still receives the arguments of each call. Read the privacy page before you paste anything that is not public.

If it does not work

The tool does not show up

In Claude, enable the connector in the conversation from the plus button, then Connectors. In Claude Code, run claude mcp list from the same directory you added it in, then start a new session: a running session does not load a new server.

429 or rate_limited

Each server takes 60 calls a minute from one network, and some tools take fewer. Past that the call comes back as a tool error that starts with rate_limited: wait a minute and ask again. daily_limit means the server reached its shared daily cap, which resets at 00:00 UTC. A limit is not an answer, so do not read it as no results. For higher limits, ask support@openkrill.app for a key.

JSON entry has no type

Claude Code skips an entry in .mcp.json that has a url but no type. Add "type": "http" next to the url, or add the server with claude mcp add --transport http, which writes the type for you. The VS Code entry needs the same type field. Cursor and Pi read the url alone.

A call checked on 2026-10-17

example.com is a reserved public name, so the check is repeatable and does not probe a private brand. The request below was posted to https://names.openkrill.app/mcp as tools/call. HTTP 200. Source: the Startup Name Check server, read 2026-10-17.

{
  "method": "tools/call",
  "params": {
    "name": "check_domain_availability",
    "arguments": {
      "names": [
        "example.com"
      ]
    }
  }
}

asOf. 2026-10-17
notice. Indicative only: this is the status right now, it does not reserve anything, and premium or reserved names can be taken or cost more. A registration cost, when shown, is Cloudflare Registrar's figure and is not a charge.
names. 1 returned

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.

Using it in production

Nothing to install and nothing to run: no package, no Python or Node.js version and no environment variable. Startup Name Check runs on our servers, and your client only needs the URL https://names.openkrill.app/mcp.

Rate limit	60 tool calls a minute from one network. `initialize` and `tools/list` do not count.
Daily cap	25000 tool calls a day per server, shared by every caller. It resets at 00:00 UTC.
At a limit	The call comes back as a tool error that starts with `rate_limited` (wait a minute) or `daily_limit` (try after 00:00 UTC), never as a partial answer.
Key	None. Do not add an `Authorization` header or a key field.
Higher limits	Email support@openkrill.app with the server name, the calls a day you expect and what they are for. We answer within 1 business day.
Freshness	Some answers come from a short cache. Each guide shows the date of its checked call; repeat a call when you need a newer reading.
Uptime	Scheduled test calls check the servers through the same endpoint. There is no SLA yet.
Data	What each server receives and keeps is on the privacy page.

Use it in other apps

Roles that use Startup Name Check

Startup founder guide

Frequently asked questions

How do I install the Startup Name Check MCP server in Claude?

In Claude, open Customize, then Connectors, choose Add custom connector and paste https://names.openkrill.app/mcp. In Claude Code, run claude mcp add --transport http names https://names.openkrill.app/mcp. No restart is needed for either.

Do I need an API key to run Startup Name Check in Claude?

No. This server takes no API key. For higher limits, email support@openkrill.app with the server name (Startup Name Check), the calls a day you expect and what they are for. We answer within 1 business day.

What should I do if Startup Name Check does not connect in Claude?

Check that the connector URL ends in /mcp and that Advanced settings are empty. In Claude Code, run claude mcp get names; a JSON entry with a url but no type is skipped, so add type http.

Words on this page

Source: plugin listing for names in this repository, and a live tools/call on 2026-10-17. As of 2026-10-17.