MCP server documentation

Just Domain turns any MCP-aware assistant into a domain-naming partner. Ask the assistant to find a domain, and it calls search_domains against our registrar backend to return live availability and price for the TLDs you care about. The assistant suggests candidates; the user opens a checkout link to register.

What it’s good for:

• Naming a new product, startup, side project, or rebrand.
• Finding alternatives when the obvious .com is taken - across modern TLDs like .ai, .io, .co.
• Comparing pricing across TLDs before committing to a name.
• Quick “is this name taken?” lookups inside a conversation.

New to giving an assistant a live domain lookup? See how AI assistants search domains for a focused walkthrough of what the search returns and where the boundary is. The server’s public metadata (name, description, endpoint) lives at github.com/just-done/just-domain-mcp.

Fastest path: Just Domain is listed in the Claude connector directory - one click from claude.ai, nothing to paste. The manual setup below reaches the identical server.

Claude.ai (web & desktop)

1. Open Settings → Connectors in Claude.
2. Click Add custom connector and paste the server URL:

https://mcp.justdomain.ai/

3. Save. Leave authentication set to None - Just Domain’s search tool is public.
4. Start a new conversation and ask: “Find me a short .ai domain for a notes app.”

Claude Code

claude mcp add just-domain https://mcp.justdomain.ai/ --transport http

After the command completes, run /mcp inside Claude Code to confirm the server is connected. Claude Code also reads a project .mcp.json in the JSON format shown in section 4.

In ChatGPT (Plus, Pro, Team, or Enterprise), open Settings → Connectors → Add a developer connector and paste the server URL:

https://mcp.justdomain.ai/

Leave authentication set to None. Once added, mention the connector in a new conversation and ChatGPT can call search_domains on your behalf and render results in the embedded UI widget.

Want to see the flow before setting anything up? Open a prefilled example prompt in ChatGPT. Without the connector, ChatGPT answers from memory; with it, every availability check is live.

Building with ChatGPT Sites? Sites hosts your site but doesn’t register domains - see a domain for your ChatGPT site for the two-step connect.

Cursor

One click if Cursor is installed: Add to Cursor (a cursor:// install link with the server URL prefilled). Or add it by hand in ~/.cursor/mcp.json:

{
  "mcpServers": {
    "just-domain": {
      "url": "https://mcp.justdomain.ai/"
    }
  }
}

Any MCP-compatible client

Just Domain follows the standard Streamable HTTP MCP transport. Any client that connects to a hosted MCP server can use it. Clients that read a JSON config (Cursor, Claude Code’s .mcp.json, and others) take the same block:

{
  "mcpServers": {
    "just-domain": {
      "url": "https://mcp.justdomain.ai/"
    }
  }
}

Point your client at https://mcp.justdomain.ai/ with no auth headers. Note the endpoint is served at the host root - there is no /mcp path suffix.

The MCP surface intentionally ships a single, focused tool. There are no account-management, billing, DNS, or purchase tools - keeping the surface minimal makes the assistant’s job easier and the trust boundary obvious.

search_domains · read-only

Checks one or more candidate domain names and returns, for each, whether it’s available, its first-year price, its renewal price, and - for available names - a ready-to-open checkout URL.

Inputs

• domains - array of fully-qualified names to check (e.g. ["oatmeal.ai", "oatmeal.io", "oatmeal.com"]).

Returns

A results array, one entry per requested name. Each entry is shaped like:

{
  "fqdn": "oatmeal.ai",
  "name": "oatmeal",
  "tld": "ai",
  "available": true,
  "status": "free",
  "premium": false,
  "price":         { "currency": "USD", "formatted": "<first-year price>" },
  "renewal_price": { "currency": "USD", "formatted": "<annual renewal>" },
  "checkout_url": "https://justdomain.ai/checkout?sld=oatmeal&tld=ai",
  "warnings": []
}

Each price / renewal_price object also carries amount_minor (an integer in the smallest currency unit) alongside the human-readable formatted string. When a domain is unavailable, its entry still appears with available: false and no checkout_url, so the assistant can suggest alternatives without a follow-up call.

Paste any of these into a Claude or ChatGPT conversation with Just Domain connected.

See the full privacy policy and security policy for details.

Stuck, hit a bug, or want a TLD we don’t list yet?

This documentation is a living document. Last updated July 15, 2026.