NDC-MCP Connector

A Native Data Connector (NDC) that bridges Hasura DDN with Model Context Protocol (MCP) servers, exposing MCP resources as collections and tools as functions/procedures.

Features

• Dynamic Schema Generation: Automatically generates NDC schema from MCP server introspection
• Multiple Transports: Supports stdio (local processes) and HTTP (remote servers)
• Multiple Servers: Connect to multiple MCP servers simultaneously
• Resource Mapping: MCP resources → NDC collections
• Tool Execution: MCP tools → NDC functions/procedures
• Naming Convention: {server_name}__{resource_or_tool} pattern

Quick Start

1. Clone and build:

   git clone https://github.com/hasura/ndc-mcp-rs.git
   cd ndc-mcp-rs
   cargo build

2. Configure servers in configuration/configuration.json:

   {
     "servers": {
       "filesystem": {
         "type": "stdio",
         "command": "npx",
         "args": ["-y", "@modelcontextprotocol/server-filesystem", "/path/to/directory"]
       },
       "remote": {
         "type": "http",
         "url": "http://localhost:8080/mcp",
         "headers": {
           "Authorization": "Bearer your-token"
         },
         "timeout_seconds": 30
       }
     }
   }

3. Start the connector:

   just serve
   # or: cargo run --bin mcp-connector -- serve --configuration configuration

4. Test the schema:

   curl http://localhost:8080/schema | jq

Configuration

The connector uses a single configuration file configuration/configuration.json where you define your MCP servers. The connector automatically introspects the servers at startup to discover available resources and tools.

Transport Types

• stdio: For local MCP servers (Node.js packages, Python scripts, etc.)
• http: For remote MCP servers using streamable HTTP transport

Development

# Build
just build

# Format code
just format

# Run clippy
just clippy

# Serve the connector
just serve

Prerequisites

• Rust 1.85.0+ (edition 2021)
• MCP servers to connect to

License

MIT License - see LICENSE file for details.