Nexus is a production-ready Model Context Protocol (MCP) server that brings AI-powered web search directly into your development environment. Get intelligent search results with proper citations in Claude Desktop, Cursor, or any MCP-compatible client - all with a single command.

• 🎯 Zero Setup: Ready in 30 seconds with npx - no installation, no configuration
• 🧠 AI-Powered: Uses Perplexity Sonar models for intelligent, current web search
• 📚 Source Citations: Get authoritative sources with every search result
• 🔧 Developer-First: Built for developers who want AI capabilities without complexity
• ⚡ Production-Ready: Enterprise-grade reliability with comprehensive error handling

🚀 Zero-install setup - Ready in 30 seconds!

• Node.js 16 or higher
• An OpenRouter API key (get one at OpenRouter)

No build steps, no dependencies, no setup required:

# Set your OpenRouter API key
export OPENROUTER_API_KEY=your-api-key-here
# Run the server instantly
npx nexus-mcp

That's it! The server is now running and ready for MCP client connections.

# Test the CLI help
npx nexus-mcp --help
# Test the version
npx nexus-mcp --version
# Run with your API key
OPENROUTER_API_KEY=your-key npx nexus-mcp

For local development or customization:

1. Clone the repository:

git clone https://github.com/adawalli/nexus.git
cd nexus

2. Install dependencies:

npm install

3. Build the server:

npm run build

4. Configure your OpenRouter API key:

# Copy the example environment file
cp .env.example .env
# Edit .env and add your actual API key
# OPENROUTER_API_KEY=your-api-key-here

5. Test the server:

npm start

The easiest way to integrate with any MCP client is using NPX:

Add this server to your Claude Code MCP settings:

1. Open your MCP settings file (usually ~/.claude/mcp_settings.json)

2. Add the server configuration using NPX:

{
  "mcpServers": {
    "nexus": {
      "command": "npx",
      "args": ["nexus-mcp"],
      "env": {
        "OPENROUTER_API_KEY": "your-api-key-here"
      }
    }
  }
}

3. Restart Claude Code

That's it! No installation, no build steps, no path configuration required.

Configure the server in Cursor's MCP settings:

1. Open Cursor settings and navigate to MCP servers

2. Add a new server with:

   • Name: nexus
   • Command: npx
   • Args: ["nexus-mcp"]
   • Environment Variables:
     • OPENROUTER_API_KEY: your-api-key-here

3. Restart Cursor

For any MCP-compatible client, use these connection details:

• Transport: stdio
• Command: npx
• Args: ["nexus-mcp"]
• Environment Variables: OPENROUTER_API_KEY=your-api-key-here

If you prefer using a local installation (after following the local development setup):

{
  "mcpServers": {
    "nexus": {
      "command": "node",
      "args": ["/path/to/nexus-mcp/dist/cli.js"],
      "env": {
        "OPENROUTER_API_KEY": "your-api-key-here"
      }
    }
  }
}

Once integrated, you can use the search tool in your MCP client:

Use the search tool to find information about "latest developments in AI"

Search for "climate change solutions" using:
- Model: perplexity/sonar
- Max tokens: 2000
- Temperature: 0.3

The main search tool that provides AI-powered web search capabilities.

Parameters:

• query (required): Search query (1-2000 characters)
• model (optional): Perplexity model to use (default: "perplexity/sonar")
• maxTokens (optional): Maximum response tokens (1-4000, default: 1000)
• temperature (optional): Response randomness (0-2, default: 0.7)

Example Response:

Based on current information, here are the latest developments in AI...
[Detailed AI-generated response with current information]
---
**Search Metadata:**
- Model: perplexity/sonar
- Response time: 1250ms
- Tokens used: 850
- Sources: 5 found

• OPENROUTER_API_KEY (required): Your OpenRouter API key
• NODE_ENV (optional): Environment setting (development, production, test)
• LOG_LEVEL (optional): Logging level (debug, info, warn, error)

The server supports additional configuration through environment variables:

• OPENROUTER_TIMEOUT_MS: Request timeout in milliseconds (default: 30000)
• OPENROUTER_MAX_RETRIES: Maximum retry attempts (default: 3)
• OPENROUTER_BASE_URL: Custom OpenRouter API base URL

The server provides a configuration status resource at config://status that shows:

• Server health status
• Configuration information (with masked API key)
• Search tool availability
• Server uptime and version

"npx: command not found"

• Ensure Node.js 16+ is installed: node --version
• Update npm: npm install -g npm@latest

"Cannot find package 'nexus-mcp'"

• The package may not be published yet. Use local installation instead
• Verify network connectivity for npm registry access

NPX takes a long time to start

• This is normal on first run as NPX downloads the package
• Subsequent runs will be faster due to caching
• For faster startup, use local installation instead

"Permission denied" errors with NPX

• Try: npx --yes nexus-mcp --stdio
• Or set npm permissions: npm config set user 0 && npm config set unsafe-perm true

"Search functionality is not available"

• Ensure OPENROUTER_API_KEY environment variable is set
• Verify your API key is valid at OpenRouter
• Check the server logs for initialization errors

"Authentication failed: Invalid API key"

• Double-check your API key format and validity
• Ensure the key has sufficient credits/permissions
• Test the key directly at OpenRouter dashboard

"Rate limit exceeded"

• Wait for the rate limit to reset (usually 1 minute)
• Consider upgrading your OpenRouter plan for higher limits
• Monitor usage in your OpenRouter dashboard

Connection timeouts

• Check your internet connection
• The server will automatically retry failed requests
• Increase timeout if needed: OPENROUTER_TIMEOUT_MS=60000

MCP client can't connect to server

• Verify your MCP configuration uses the correct command and arguments
• Check that Node.js 16+ is available in your MCP client's environment
• Ensure the API key is properly set in the environment variables

Enable debug logging by:

For local development: Add LOG_LEVEL=debug to your .env file

For MCP clients: Add LOG_LEVEL: "debug" to the env section of your MCP configuration

This will provide detailed information about:

• Configuration loading
• API requests and responses
• Error details and stack traces
• Performance metrics

You can test if the server is working by checking the configuration status resource in your MCP client, or by running a simple search query.

For developers working on this server:

# Development with hot reload
npm run dev
# Run tests
npm test
# Run tests with coverage
npm run test:coverage
# Lint code
npm run lint
# Format code
npm run format

This server uses OpenRouter's API, which charges based on token usage:

• Perplexity Sonar models: Check current pricing at OpenRouter Models
• Usage monitoring: Track consumption through the OpenRouter dashboard
• Cost control: Set usage limits in your OpenRouter account
• Optimization: Nexus includes built-in rate limiting and intelligent caching

We welcome contributions from developers of all experience levels!

Contributors are recognized in our:

• Contributors list
• Release notes for significant contributions
• Community spotlights and testimonials

• Model Context Protocol - The standard we implement
• OpenRouter - Our AI model provider
• Claude Desktop - Primary MCP client
• Cursor - AI-powered code editor with MCP support

MIT License - see LICENSE file for details.