Startup Name Check MCP in ChatGPT: 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 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 this URL. Include the /mcp path. Do not add a tunnel id: this server is already public.
```
https://names.openkrill.app/mcp
```
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.

If it does not work

The tool does not show up

Check that the endpoint ends in /mcp. Open the connection, select Refresh, then start a new conversation and add the connection from the tools menu. A conversation started before the connection was added does not see its tools.

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.

Developer mode is missing in ChatGPT

Developer mode is in ChatGPT settings, then Security and login, on the web. In a Team or Enterprise workspace an admin can hide it, so ask the admin to allow custom connections first. Without developer mode ChatGPT cannot add a custom MCP server.

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 ChatGPT?

Turn on Developer mode in ChatGPT settings, then Security and login. In ChatGPT plugins, select the plus button and paste https://names.openkrill.app/mcp as the public endpoint. Start a new conversation and add the connection from the tools menu.

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

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 ChatGPT?

Check that the endpoint ends in /mcp. Open the connection, select Refresh, and start a new conversation. If Developer mode is missing, a workspace admin has to allow it first.

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.