Startup Name Check in ChatGPT
Is that name's domain taken?. The MCP server is https://names.openkrill.app/mcp. No key. The steps below are only for ChatGPT. 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 ChatGPT
ChatGPT does not read a local config file. A custom MCP server is added in the product, and only after developer mode is on. These steps were checked against OpenAI's plugin connect guide and the ChatGPT MCP guide on 2026-10-01. Developer mode can be hidden by a workspace policy, so a Team or Enterprise admin may have to allow it first.
- Open ChatGPT settings, then Security and login, and turn on Developer mode.
- Open ChatGPT plugins and select the plus button.
- Enter a name such as "Startup Name Check" and a one-line description of what you want it to answer.
- Under Connection, choose the public endpoint and paste
https://names.openkrill.app/mcp. Include the/mcppath. Do not add a tunnel id: this server is already public. - Create the connection and review the tools ChatGPT lists. You should see
check_domain_availability. The feedback tools on the same server are optional and not required for the lookup. - Start a new conversation, add the connection from the tools menu, and ask: Is acme.com available?
No API key and no OAuth client id are required. The server answers without a login. Calls are limited per network and per day, and a limit comes back as a tool error rather than a partial answer. If the tool list is stale after a server change, open the connection and select Refresh, then start a new conversation.
The ChatGPT desktop app, Codex CLI and IDE extension share a different config. In the desktop app, open Settings, then MCP servers, choose Add server, select Streamable HTTP, and paste the same URL. In ~/.codex/config.toml the equivalent is a table named mcp_servers.names with url = "https://names.openkrill.app/mcp". ChatGPT on the web does not read that file. A published directory listing is also a different path: this page is the developer-mode connection, not a claim that Startup Name Check is already in the ChatGPT directory.
Treat the server as untrusted until you have read a few answers. A remote MCP server sees the arguments the model sends. Startup Name Check is read-only and documents what it sends onward on the privacy page.
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.