OpenRPC

What is openrpc-mpc-server?

openrpc-mpc-server is a Model Context Protocol (MCP) server designed to provide JSON-RPC functionality through OpenRPC. It allows users to interact with and discover JSON-RPC APIs, acting as a bridge between applications and JSON-RPC services.

How to use openrpc-mpc-server?

To use openrpc-mpc-server, you first need to install its dependencies using npm install. For development, you can build the server with npm run build or use npm run watch for auto-rebuild. To integrate it with applications like Claude Desktop, you need to add a specific server configuration to the application's configuration file (e.g., claude_desktop_config.json). Debugging can be done using the MCP Inspector by running npm run inspector, which provides a URL for browser-based debugging tools.

Key Features of openrpc-mpc-server

• rpc_call: This tool enables users to call arbitrary JSON-RPC methods. You can specify the server URL, method name, and parameters, and it returns JSON-formatted results.
• rpc_discover: This feature allows for the discovery of available JSON-RPC methods. It utilizes OpenRPC's rpc.discover specification to list all methods exposed by a given server.
• OpenRPC Integration: Leverages OpenRPC for standardized API description and interaction.
• MCP Server: Functions as a Model Context Protocol server, facilitating communication within the MCP ecosystem.

Use Cases of openrpc-mpc-server

• API Interaction: Directly call and interact with any JSON-RPC API.
• API Discovery: Programmatically discover the methods and capabilities of JSON-RPC services.
• Integration with MCP-compatible applications: Seamlessly integrate JSON-RPC services into applications that support the Model Context Protocol, such as Claude Desktop.
• Development and Testing: Aid in the development and testing of JSON-RPC services by providing tools for calling and discovering methods.

FAQ from openrpc-mpc-server

Q: How do I debug the MCP server? A: Debugging can be challenging due to communication over stdio. It is recommended to use the MCP Inspector. Run npm run inspector to get a URL for browser-based debugging tools.

Q: What is OpenRPC? A: OpenRPC is a standard for describing JSON-RPC APIs, similar to OpenAPI for REST APIs. It allows for machine-readable descriptions of JSON-RPC services, enabling tools and clients to interact with them more easily.

Q: Can I use this with applications other than Claude Desktop? A: While the documentation specifically mentions Claude Desktop, the server provides standard JSON-RPC functionality via OpenRPC, making it potentially compatible with any application or system that can interact with JSON-RPC services and can be configured to use an MCP server.

OpenRPC MCP Server

A Model Context Protocol (MCP) server that provides JSON-RPC functionality through OpenRPC.

https://github.com/user-attachments/assets/3447175a-f921-4ded-8250-b611edb2fb67

Features

Tools

• rpc_call - Call arbitrary JSON-RPC methods
  • Specify server URL, method name, and parameters
  • Returns JSON-formatted results
• rpc_discover - Discover available JSON-RPC methods
  • Uses OpenRPC's rpc.discover specification
  • Lists all methods on a given server

Development

Install dependencies:

npm install

Build the server:

npm run build

For development with auto-rebuild:

npm run watch

Installation

To use with Claude Desktop, add the server config:

On MacOS: ~/Library/Application Support/Claude/claude_desktop_config.json On Windows: %APPDATA%/Claude/claude_desktop_config.json

{
  "mcpServers": {
    "openrpc": {
      "command": "npx",
      "args": ["-y", "openrpc-mcp-server"]
    }
  }
}

Debugging

Since MCP servers communicate over stdio, debugging can be challenging. We recommend using the MCP Inspector:

npm run inspector

The Inspector will provide a URL to access debugging tools in your browser.