Domain Availability Checker MCP

MCP Domain Availability Checker

Features

• Domain Availability Checking

  • Check availability across 50+ popular TLD extensions

  • Support for popular (.com, .io, .ai), country (.us, .uk, .de), and new TLDs (.app, .dev, .tech)

  • Authoritative verification over RDAP, the protocol that replaced WHOIS

  • WHOIS and DNS fallback for the few TLDs that publish no RDAP service

  • Smart TLD suggestions organized by popularity

• Search Capabilities

  • Check specific domains with exact TLD matching

  • Bulk checking across supported extensions for a given name

  • Parallel processing for faster domain queries

  • Organized results by TLD categories

• MCP Integration

  • Easy setup with uvx package management

  • Seamless integration with Claude Desktop

  • Real-time availability status updates

  • Performance metrics and timing information

• AI Assistant Features

  • Natural language domain queries through Claude

  • Automated domain suggestion workflows

  • Smart recommendations based on availability

Demo

00:00 - Checking google.com availability
Testing a well-known premium domain to demonstrate the domain checking functionality and alternative TLD suggestions.

00:20 - Testing myawesomesite.com
Verifying availability for a custom domain name and exploring alternative extension options.

00:40 - Verifying techstartup2026.io
Exploring tech startup domain options and checking availability across multiple TLD extensions.

01:00 - Analyzing aitools domain
Checking competitive AI industry domains and analyzing market availability for startup naming.

Requirements

• Python 3.10 or higher (3.12 recommended)

• Claude Desktop

• uv package manager

Dependencies Installation

Install uv package manager using one of these methods:

Official installer (recommended):

curl -LsSf https://astral.sh/uv/install.sh | sh

Homebrew (macOS/Linux):

brew install uv

Install Homebrew (if needed):

• Visit https://brew.sh for installation instructions on all operating systems

• Or run: /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

The MCP server automatically manages Python dependencies through uvx.

Installation

Zero-Clone Installation (Recommended)

The MCP Domain Availability Checker supports direct installation without cloning repositories, using uvx for package management.

Configuration

The Claude Desktop configuration file is located at:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

• Windows: %APPDATA%\Claude\claude_desktop_config.json

• Linux: ~/.config/Claude/claude_desktop_config.json

Edit this file to add the Domain Availability MCP configuration:

{
  "mcpServers": {
    "mcp-domain-availability": {
      "command": "uvx",
      "args": [
        "--python=3.12",
        "--from",
        "git+https://github.com/imprvhub/mcp-domain-availability",
        "mcp-domain-availability"
      ]
    }
  }
}

If you already have other MCPs configured, simply add the "mcp-domain-availability" section inside the "mcpServers" object:

{
  "mcpServers": {
    "otherMcp": {
      "command": "...",
      "args": ["..."]
    },
    "mcp-domain-availability": {
      "command": "uvx",
      "args": [
        "--python=3.12",
        "--from",
        "git+https://github.com/imprvhub/mcp-domain-availability",
        "mcp-domain-availability"
      ]
    }
  }
}

Installing via Smithery

To install mcp-domain-availability for Claude Desktop automatically via Smithery:

npx -y @smithery/cli@latest mcp add imprvhub/mcp-domain-availability --client claude

Manual Installation

For development or local testing:

1. Clone the repository:

git clone https://github.com/imprvhub/mcp-domain-availability
cd mcp-domain-availability

2. Install dependencies:

uv sync

3. Run locally:

uv run src/mcp_domain_availability/main.py

Deploying with Docker to Google Cloud Run

The MCP server supports two transport modes:

• stdio (default): For Claude Desktop integration via stdin/stdout

• sse: For HTTP/web deployments like Google Cloud Run

When deploying to Cloud Run, the MCP_TRANSPORT environment variable must be set to sse.

Prerequisites:

• Google Cloud SDK installed and authenticated (gcloud auth login)

• Docker installed and running

• A Google Cloud Project with the Cloud Run and Container Registry APIs enabled

Using the Deployment Script

The easiest way to deploy is to use the deploy.sh script.

1. Edit the script: Open deploy.sh and replace ... with your Google Cloud PROJECT_ID. You can also change the REGION if needed.

2. Run the script: Make the script executable and run it.

    chmod +x deploy.sh
    ./deploy.sh

The script will build the Docker image, push it to Google Container Registry, and deploy it to Cloud Run with `MCP_TRANSPORT=sse`.

Manual Deployment

Alternatively, you can run the commands manually.

1. Set environment variables:

    export PROJECT_ID="<YOUR_PROJECT_ID>"
    export REGION="<YOUR_REGION>"
    export IMAGE="gcr.io/$PROJECT_ID/mcp-domain-availability:latest"

2. Build and push the Docker image:

    docker buildx build --platform linux/amd64 -t $IMAGE --push .

3. Deploy to Google Cloud Run:

    gcloud run deploy mcp-domain-availability \
      --image $IMAGE \
      --region $REGION \
      --platform managed \
      --allow-unauthenticated \
      --port 8080 \
      --set-env-vars MCP_TRANSPORT=sse \
      --project $PROJECT_ID

Note: For local Claude Desktop usage, no environment variables are needed. The server defaults to stdio transport mode.

How It Works

ICANN retired WHOIS as the required registration-data protocol in January 2025 in favour of RDAP (RFC 7482/9082), so RDAP is the primary source here. It is unambiguous: a registry's RDAP service answers 404 for an unregistered domain and 200 for a registered one.

1. RDAP — the registry's own RDAP service, discovered through IANA's bootstrap registry (about 1,200 TLDs). This is authoritative.

2. WHOIS — only for TLDs with no RDAP service (.io, .co, .me, .de, .es and some other ccTLDs). The registry's WHOIS server is found via IANA referral and queried directly over port 43; only the first lines of the response are interpreted.

3. DNS — a name that resolves is definitely registered.

Each domain comes back as one of three statuses:

undetermined exists because the previous version reported a domain as available whenever a WHOIS lookup raised an error — including when the machine had no whois binary installed, in which case every domain looked free. A result you cannot trust is now labelled as such.

Domains are checked concurrently, capped at 10 in flight to stay within registry rate limits.

Available Tools

Changed in 0.5.0: the --domain flag is no longer required — ask for a domain in plain language. The flag is still accepted so existing prompts keep working. Bulk TLD checking moved into its own tool, so asking about one domain no longer triggers ~95 lookups.

Supported TLD Categories

Popular TLDs (12)

com, net, org, io, ai, app, dev, co, xyz, me, info, biz

Country TLDs (36)

us, uk, ca, au, de, fr, it, es, nl, jp, kr, cn, in, br, mx, ar, cl, pe, ru, pl, cz, ch, at, se, no, dk, fi, be, pt, gr, tr, za, eg, ma, ng, ke

New TLDs

tech, online, site, website, store, shop, cloud, digital, blog, news & more.

Example Usage

Here are examples of how to use the MCP Domain Availability Checker with Claude:

Single Domain Check

Is mysite.com available?

Domain Name Research

Check "startup" across all TLDs

Specific Domain Verification

Is awesome.io taken?

Output Format

The tool provides comprehensive results including:

• Requested Domain: Status of the exact domain queried (if a specific TLD was provided)

• Available Domains: Confirmed unregistered, sorted alphabetically

• Unavailable Domains: Confirmed registered

• Undetermined Domains: No authoritative answer, with the reason

• Summary Statistics: Breakdown by TLD categories (Popular, Country, New TLDs)

• Performance Metrics: Check duration and which source answered (rdap, whois or dns)

Development

Run the offline test suite (no network required):

uv sync
uv run python -m unittest discover -s tests -v

Check a domain from the command line:

uv run mcp-domain-availability-cli example.com
uv run mcp-domain-availability-cli mysite popular

Troubleshooting

"Server disconnected" error

If you see connection errors in Claude Desktop:

1. Verify uvx installation:

   • Run uvx --version to ensure uvx is properly installed

   • Reinstall uv if necessary: curl -LsSf https://astral.sh/uv/install.sh | sh

2. Check Python version:

   • Ensure Python 3.10+ is available: python3 --version

"ModuleNotFoundError: No module named 'mcp.server.fastmcp'"

Version 2.0 of the MCP Python SDK removed mcp.server.fastmcp. Releases of this server before 0.5.0 imported it without capping the SDK version, so any fresh install picked up SDK 2.x and failed at startup. 0.5.0 is written for SDK 2.x. If you still see the error, uv is running a cached copy of the old code:

1. Refresh the cached install:

   • Run uvx --refresh --from git+https://github.com/imprvhub/mcp-domain-availability mcp-domain-availability

   • If you installed it as a persistent tool, run uv tool upgrade mcp-domain-availability

2. Remove the old workaround: if you added "--with", "mcp<2.0.0" to your client config, delete it. 0.5.0 requires SDK 2.x and will not start with that pin.

DNS resolution issues

If domain checks are failing:

1. Network connectivity:

   • Verify internet connection is stable

   • Check if DNS servers are accessible

2. Rate limiting:

   • Large bulk checks may hit rate limits from DNS/WHOIS services

   • The tool uses a semaphore to limit concurrent requests to 20

Configuration issues

If the MCP server isn't starting:

1. Verify configuration syntax:

   • Ensure JSON syntax is valid in claude_desktop_config.json

   • Check that all brackets and quotes are properly matched

2. Restart Claude Desktop:

   • Close and restart Claude Desktop after configuration changes

Related MCP server: Domain Finder MCP Server

Development

Project Structure

• main.py: Main entry point with MCP server and domain checking logic

• Domain checking functions with DNS, WHOIS, and socket fallback methods

• TLD management with categorized lists

• Async processing for parallel domain checks

Building

uv build

Testing

uv run pytest

Local Development

uv run main.py

Security Considerations

The MCP Domain Availability Checker makes external network requests to DNS servers and WHOIS services. Users should be aware that:

• Domain queries may be logged by DNS providers

• WHOIS queries are typically logged and may be rate-limited

• No personal information is transmitted beyond the domain names being checked

• All queries are read-only and do not modify any external systems

Contributing

Contributions are welcome! Areas for improvement include:

• Adding support for additional TLD categories

• Implementing caching mechanisms for faster repeated queries

• Enhancing WHOIS parsing for more detailed domain information

• Improving error handling and retry mechanisms

License

This project is licensed under the Mozilla Public License 2.0 - see the LICENSE file for details.

Related Links

• Model Context Protocol

• Claude Desktop

• uv Package Manager

• MCP Series