Nats MCP Server

🚀 NATS MCP Server

An MCP (Model Context Protocol) server that accesses NATS (a cloud-native messaging system) via the Nats CLI.

✨ Features

• Publish messages with advanced options (headers, templates, reply subjects).
• Subscribe to subjects with configurable timeouts and message counts.
• Support the request-response pattern with header information.
• Fully integrate with the NATS CLI.
• Handle errors and perform cleanup.

📦 Installation

Requirements

• Node.js >= 14.0.0
• NATS CLI (nats)

Install the NATS CLI

macOS

Use Homebrew:

brew tap nats-io/nats-tools
brew install nats-io/nats-tools/nats

Linux

Use snap:

snap install nats

Use apt (Debian/Ubuntu):

# First, add the NATS repository
echo "deb https://dl.nats.io/nats-io/repo/deb stable" | sudo tee /etc/apt/sources.list.d/nats.list
sudo apt update && sudo apt install nats

Use yum (CentOS/RHEL):

# First, add the NATS repository
cat << EOF | sudo tee /etc/yum.repos.d/nats.repo
[nats]
name=NATS - https://nats.io
baseurl=https://dl.bintray.com/nats-io/rpm/centos/\$releasever/\$basearch/
enabled=1
gpgcheck=1
EOF
sudo yum clean all && sudo yum install nats

Windows

Use winget:

winget install nats.io.NATS

Verify the Installation

After installation, verify that it was installed correctly:

nats --version

🚀 Quick Start

Install the MCP Server

1. Clone the repository:

git clone https://github.com/yourusername/nats-mcp-server.git
cd nats-mcp-server

2. Install dependencies:

npm install

3. Build the project:

npm run build

4. Start the server:

node build/index.js

💻 Usage Examples

Add to MCP Configuration

For Cline (VSCode Extension)

Add to ~/Library/Application Support/Code/User/globalStorage/saoudrizwan.claude-dev/settings/cline_mcp_settings.json:

{
  "mcpServers": {
    "nats": {
      "command": "node",
      "args": ["/path/to/nats-mcp-server/build/index.js"],
      "env": {
        "NATS_URL": "nats://localhost:4222"
      }
    }
  }
}

For Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "nats": {
      "command": "node",
      "args": ["/path/to/nats-mcp-server/build/index.js"],
      "env": {
        "NATS_URL": "nats://localhost:4222"
      }
    }
  }
}

Command Reference

Publish

Publish a message to a specified subject:

node build/index.js publish --subject <subject> --message "<message>"

Subscribe

Subscribe to messages on a specified subject:

node build/index.js subscribe --subject <subject> [--timeout <timeout>] [--count <message count>]

Request

Send a request to a specified subject and wait for a reply:

node build/index.js request --subject <subject> --message "<request message>" [--timeout <timeout>]

Template Functions

When using templates (template: true), the following functions are available:

• Count: Message number
• TimeStamp: Current time in RFC3339 format
• Unix: Number of seconds since 1970 in UTC
• UnixNano: Number of nanoseconds since 1970 in UTC
• Time: Current time
• ID: Unique ID
• Random(min, max): Random string of specified length

Example:

const result = await mcp.useTool("nats", "publish", {
  subject: "test",
  message: "Random data: {{ Random 10 100 }}",
  template: true
});

🔧 Technical Details

Error Handling

The server includes the following error handling:

• Connection failures
• Invalid parameters
• Timeouts
• Network errors
• NATS-specific errors
• CLI execution errors

Development

1. Clone the repository:

git clone https://github.com/yourusername/nats-mcp-server.git
cd nats-mcp-server

2. Install dependencies:

npm install

3. Build the project:

npm run build

4. Start the development server:

node build/index.js

Contribution

1. Fork the repository.
2. Create a feature branch (git checkout -b feature/amazing-feature).
3. Commit your changes (git commit -m 'Add some amazing feature').
4. Push to the branch (git push origin feature/amazing-feature).
5. Open a Pull Request.

📄 License

MIT

Acknowledgments

• NATS.io: A high-performance communication protocol for distributed systems.
• Claude: A powerful AI assistant.