registry/docs/guides/publishing/publish-server.md

Publish Your MCP Server

Complete guide to publishing an MCP server to the registry.

What You'll Learn

By the end of this tutorial, you'll have:

• Created a server.json file for your MCP server
• Authenticated with the registry
• Successfully published your server
• Verified your server appears in the registry

Prerequisites

• An MCP server you've already built (follow this guide if you don't have one already)
• Your server published to a package registry (npm, PyPI, Docker Hub, etc.)

Step 1: Install the Publisher CLI

Download and build the MCP publisher tool:

# Clone the registry repository (requires Go 1.24+)
git clone https://github.com/modelcontextprotocol/registry
cd registry
make publisher

# The binary will be at cmd/publisher/bin/mcp-publisher
export PATH=$PATH:$(pwd)/cmd/publisher/bin

Step 2: Initialize Your server.json

Navigate to your server's directory and create a template:

cd /path/to/your/mcp-server
mcp-publisher init

This creates a server.json with auto-detected values. You'll see something like:

{
  "$schema": "https://static.modelcontextprotocol.io/schemas/2025-07-09/server.schema.json",
  "name": "io.github.yourname/your-server",
  "description": "A description of your MCP server",
  "version_detail": {
    "version": "1.0.0"
  },
  "packages": [
    {
      "registry_type": "npm",
      "identifier": "your-package-name",
      "version": "1.0.0"
    }
  ]
}

Step 3: Configure Your Server Details

Edit the generated server.json:

Choose Your Namespace

The name field determines authentication requirements:

• io.github.yourname/* - Requires GitHub authentication
• com.yourcompany/* - Requires DNS or HTTP domain verification

Add Package Validation

Your package must include validation metadata to prove ownership.

📦 NPM Packages

Requirements

Add an mcpName field to your package.json:

{
  "name": "your-npm-package",
  "version": "1.0.0",
  "mcpName": "io.github.username/server-name"
}

How It Works

• Registry fetches https://registry.npmjs.org/your-npm-package
• Checks that mcpName field matches your server name
• Fails if field is missing or doesn't match

Example server.json

{
  "name": "io.github.username/server-name",
  "packages": [
    {
      "registry_type": "npm",
      "identifier": "your-npm-package",
      "version": "1.0.0"
    }
  ]
}

The official MCP registry currently only supports the NPM public registry (https://registry.npmjs.org).

🐍 PyPI Packages

Requirements

Include your server name in your package README file using this format:

MCP name format: mcp-name: io.github.username/server-name

Add it to your README.md file (which becomes the package description on PyPI).

How It Works

• Registry fetches https://pypi.org/pypi/your-package/json
• Passes if mcp-name: server-name is in the README content

Example server.json

{
  "name": "io.github.username/server-name",
  "packages": [
    {
      "registry_type": "pypi",
      "identifier": "your-pypi-package",
      "version": "1.0.0"
    }
  ]
}

The official MCP registry currently only supports the official PyPI registry (https://pypi.org).

📋 NuGet Packages

Requirements

Include your server name in your package's README using this format:

MCP name format: mcp-name: io.github.username/server-name

Add a README file to your NuGet package that includes the server name.

How It Works

• Registry fetches README from https://api.nuget.org/v3-flatcontainer/{id}/{version}/readme
• Passes if mcp-name: server-name is found in the README content

Example server.json

{
  "name": "io.github.username/server-name",
  "packages": [
    {
      "registry_type": "nuget",
      "identifier": "Your.NuGet.Package",
      "version": "1.0.0"
    }
  ]
}

The official MCP registry currently only supports the official NuGet registry (https://api.nuget.org).

🐳 Docker/OCI Images

Requirements

Add an annotation to your Docker image:

LABEL io.modelcontextprotocol.server.name="io.github.username/server-name"

How It Works

• Registry authenticates with Docker Hub using public token
• Fetches image manifest using Docker Registry v2 API
• Checks that io.modelcontextprotocol.server.name annotation matches your server name
• Fails if annotation is missing or doesn't match

Example server.json

{
  "name": "io.github.username/server-name", 
  "packages": [
    {
      "registry_type": "oci",
      "identifier": "yourusername/your-mcp-server",
      "version": "1.0.0"
    }
  ]
}

The identifier is namespace/repository, and version is the tag and optionally digest.

The official MCP registry currently only supports the official Docker registry (https://docker.io).

📁 MCPB Packages

Requirements

MCP reference - MCPB package URLs must contain "mcp" somewhere within them, to ensure the correct artifact has been uploaded. This may be with the .mcpb extension or in the name of your repository.

File integrity - MCPB packages must include a SHA-256 hash for file integrity verification. This is required at publish time and MCP clients will validate this hash before installation.

How to Generate File Hashes

Calculate the SHA-256 hash of your MCPB file:

openssl dgst -sha256 server.mcpb

Example server.json

{
  "name": "io.github.username/server-name",
  "packages": [
    {
      "registry_type": "mcpb",
      "identifier": "https://github.com/you/your-repo/releases/download/v1.0.0/server.mcpb",
      "file_sha256": "fe333e598595000ae021bd27117db32ec69af6987f507ba7a63c90638ff633ce"
    }
  ]
}

File Hash Validation

• Authors are responsible for generating correct SHA-256 hashes when creating server.json
• MCP clients validate the hash before installing packages to ensure file integrity
• The official registry stores hashes but does not validate them
• Subregistries may choose to implement their own validation. This enables them to perform security scanning on MCPB files, and ensure clients get the same security scanned content.

The official MCP registry currently only supports artifacts hosted on GitHub or GitLab releases.

Step 4: Authenticate

Choose your authentication method based on your namespace:

GitHub Authentication (for io.github.* namespaces)

mcp-publisher login github

This opens your browser for OAuth authentication.

DNS Authentication (for custom domains)

# Generate keypair
openssl genpkey -algorithm Ed25519 -out key.pem

# Get public key for DNS record
echo "_mcp-registry.yourcompany.com. IN TXT \"v=MCPv1; k=ed25519; p=$(openssl pkey -in key.pem -pubout -outform DER | tail -c 32 | base64)\""

# Add the TXT record to your DNS, then login
mcp-publisher login dns --domain yourcompany.com --private-key $(openssl pkey -in key.pem -noout -text | grep -A3 "priv:" | tail -n +2 | tr -d ' :\n')

Step 5: Publish Your Server

With authentication complete, publish your server:

mcp-publisher publish

You'll see output like:

✓ Validating server.json
✓ Checking package ownership
✓ Publishing to registry
✓ Server published successfully!

Your server is now available at:
https://registry.modelcontextprotocol.io/servers/io.github.yourname/weather-server

Step 6: Verify Publication

Check that your server appears in the registry:

curl https://registry.modelcontextprotocol.io/servers/io.github.yourname/weather-server

You should see your server metadata returned as JSON.

Troubleshooting

"Package validation failed" - Ensure your package includes the required validation metadata (mcpName field, README mention, or Docker label).

"Authentication failed" - Verify you've correctly set up DNS records or are logged into the right GitHub account.

"Namespace not authorized" - Your authentication method doesn't match your chosen namespace format.

Next Steps

• Update your server: Publish new versions with updated server.json files
• Set up CI/CD: Automate publishing with GitHub Actions
• Learn more: Understand server.json format in depth

What You've Accomplished

You've successfully published your first MCP server to the registry! Your server is now discoverable by MCP clients and can be installed by users worldwide.