Startup Name Check in Claude
Is that name's domain taken?. The MCP server is https://names.openkrill.app/mcp. No key. The steps below are only for Claude. A call to check_domain_availability was checked against that server on 2026-10-01.
What this server 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.
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
https://names.openkrill.app/mcp. Leave Advanced settings empty: this server does not need an OAuth client id or secret. - 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/mcpThat 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.
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.
A call checked on 2026-10-01
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 2026-10-01.
{
"method": "tools/call",
"params": {
"name": "check_domain_availability",
"arguments": {
"names": [
"example.com"
]
}
}
}- notice. Indicative only: this is the registry's status right now, it does not reserve anything, and premium or reserved names can be taken or cost more at a registrar. Trademarks are not checked.
- 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.