├── .gitignore ├── tsconfig.json ├── package.json ├── README.md ├── src └── index.ts └── LICENSE /.gitignore: -------------------------------------------------------------------------------- 1 | node_modules/ 2 | build/ 3 | *.log.env* 4 | -------------------------------------------------------------------------------- /tsconfig.json: -------------------------------------------------------------------------------- 1 | { 2 | "compilerOptions": { 3 | "target": "ES2022", 4 | "module": "Node16", 5 | "moduleResolution": "Node16", 6 | "outDir": "./build", 7 | "rootDir": "./src", 8 | "strict": true, 9 | "esModuleInterop": true, 10 | "skipLibCheck": true, 11 | "forceConsistentCasingInFileNames": true 12 | }, 13 | "include": ["src/**/*"], 14 | "exclude": ["node_modules"] 15 | } 16 | -------------------------------------------------------------------------------- /package.json: -------------------------------------------------------------------------------- 1 | { 2 | "name": "openrpc-mcp-server", 3 | "version": "0.1.2", 4 | "description": "OpenRPC MCP server", 5 | "main": "./build/index.js", 6 | "type": "module", 7 | "bin": { 8 | "openrpc-mcp-server": "./build/index.js" 9 | }, 10 | "files": [ 11 | "build" 12 | ], 13 | "scripts": { 14 | "start": "node build/index.js", 15 | "build": "tsc && node -e \"require('fs').chmodSync('build/index.js', '755')\"", 16 | "prepare": "npm run build", 17 | "watch": "tsc --watch", 18 | "inspector": "npx @modelcontextprotocol/inspector build/index.js" 19 | }, 20 | "dependencies": { 21 | "@modelcontextprotocol/sdk": "0.6.0", 22 | "@open-rpc/client-js": "^1.8.1" 23 | }, 24 | "devDependencies": { 25 | "@types/node": "^20.11.24", 26 | "typescript": "^5.3.3" 27 | } 28 | } 29 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # OpenRPC MCP Server 2 | 3 | A Model Context Protocol (MCP) server that provides JSON-RPC functionality through [OpenRPC](https://open-rpc.org). 4 | 5 | https://github.com/user-attachments/assets/3447175a-f921-4ded-8250-b611edb2fb67 6 | 7 | ## Features 8 | 9 | ### Tools 10 | 11 | - `rpc_call` - Call arbitrary JSON-RPC methods 12 | - Specify server URL, method name, and parameters 13 | - Returns JSON-formatted results 14 | - `rpc_discover` - Discover available JSON-RPC methods 15 | - Uses OpenRPC's `rpc.discover` specification 16 | - Lists all methods on a given server 17 | 18 | ## Development 19 | 20 | Install dependencies: 21 | 22 | ```bash 23 | npm install 24 | ``` 25 | 26 | Build the server: 27 | 28 | ```bash 29 | npm run build 30 | ``` 31 | 32 | For development with auto-rebuild: 33 | 34 | ```bash 35 | npm run watch 36 | ``` 37 | 38 | ## Installation 39 | 40 | To use with Claude Desktop, add the server config: 41 | 42 | On MacOS: `~/Library/Application Support/Claude/claude_desktop_config.json` 43 | On Windows: `%APPDATA%/Claude/claude_desktop_config.json` 44 | 45 | ```json 46 | { 47 | "mcpServers": { 48 | "openrpc": { 49 | "command": "npx", 50 | "args": ["-y", "openrpc-mcp-server"] 51 | } 52 | } 53 | } 54 | ``` 55 | 56 | ### Debugging 57 | 58 | Since MCP servers communicate over stdio, debugging can be challenging. We recommend using the [MCP Inspector](https://github.com/modelcontextprotocol/inspector): 59 | 60 | ```bash 61 | npm run inspector 62 | ``` 63 | 64 | The Inspector will provide a URL to access debugging tools in your browser. 65 | -------------------------------------------------------------------------------- /src/index.ts: -------------------------------------------------------------------------------- 1 | #!/usr/bin/env node 2 | import { RequestManager, HTTPTransport, Client } from "@open-rpc/client-js"; 3 | 4 | /** 5 | * This is an OpenRPC server that provides JSON-RPC functionality. 6 | * It allows: 7 | * - Discovering JSON-RPC methods via rpc.discover 8 | * - Calling arbitrary JSON-RPC methods 9 | */ 10 | 11 | import { Server } from "@modelcontextprotocol/sdk/server/index.js"; 12 | import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js"; 13 | import { 14 | CallToolRequestSchema, 15 | ListToolsRequestSchema, 16 | } from "@modelcontextprotocol/sdk/types.js"; 17 | 18 | /** 19 | * Create an MCP server with capabilities for tools and prompts 20 | * to interact with JSON-RPC servers 21 | */ 22 | const server = new Server( 23 | { 24 | name: "openrpc", 25 | version: "0.1.0", 26 | }, 27 | { 28 | capabilities: { 29 | resources: {}, 30 | tools: {}, 31 | prompts: {}, 32 | }, 33 | } 34 | ); 35 | 36 | /** 37 | * Handler that lists available tools. 38 | * Exposes two tools: 39 | * - rpc_call: For calling arbitrary JSON-RPC methods 40 | * - rpc_discover: For discovering available methods on a server 41 | */ 42 | server.setRequestHandler(ListToolsRequestSchema, async () => { 43 | return { 44 | tools: [ 45 | { 46 | name: "rpc_call", 47 | description: "Call any JSON-RPC method on a server with parameters. A user would prompt: Call method on with params ", 48 | inputSchema: { 49 | type: "object", 50 | properties: { 51 | server: { 52 | type: "string", 53 | description: "Server URL" 54 | }, 55 | method: { 56 | type: "string", 57 | description: "JSON-RPC method name to call" 58 | }, 59 | // this is a bit of a hack since claude seems to have issues with nested parameters 60 | params: { 61 | type: "string", 62 | description: "Stringified Parameters to pass to the method" 63 | } 64 | }, 65 | required: ["server", "method"] 66 | } 67 | }, 68 | { 69 | name: "rpc_discover", 70 | description: "This uses JSON-RPC to call `rpc.discover` which is part of the OpenRPC Specification for discovery for JSON-RPC servers. A user would prompt: What JSON-RPC methods does this server have? ", 71 | inputSchema: { 72 | type: "object", 73 | properties: { 74 | server: { 75 | type: "string", 76 | description: "Server URL" 77 | }, 78 | }, 79 | required: ["server"] 80 | } 81 | } 82 | ] 83 | }; 84 | }); 85 | 86 | /** 87 | * Handler for JSON-RPC tools. 88 | * Handles both method discovery and arbitrary method calls. 89 | */ 90 | server.setRequestHandler(CallToolRequestSchema, async (request) => { 91 | 92 | switch (request.params.name) { 93 | case "rpc_call": { 94 | const server = String(request.params.arguments?.server); 95 | const method = String(request.params.arguments?.method); 96 | const params = JSON.parse(String(request.params.arguments?.params)); 97 | let transport = new HTTPTransport(server); 98 | let client = new Client(new RequestManager([transport])); 99 | const results = await client.request({ method: method, params: params as any}); 100 | return { 101 | toolResult: { 102 | content: [{ 103 | type: "text", 104 | text: JSON.stringify(results, null, 2) 105 | }], 106 | isError: false 107 | } 108 | }; 109 | } 110 | case "rpc_discover": { 111 | const server = String(request.params.arguments?.server); 112 | if (!server) { 113 | throw new Error("Server is required"); 114 | } 115 | let transport = new HTTPTransport(server); 116 | let client = new Client(new RequestManager([transport])); 117 | const results = await client.request({ method: "rpc.discover" }); 118 | 119 | return { 120 | toolResult: { 121 | content: [{ 122 | type: "text", 123 | text: JSON.stringify(results, null, 2) 124 | }], 125 | isError: false 126 | } 127 | }; 128 | } 129 | 130 | default: 131 | throw new Error("Unknown tool"); 132 | } 133 | }); 134 | 135 | /** 136 | * Start the server using stdio transport. 137 | * This allows the server to communicate via standard input/output streams. 138 | */ 139 | async function main() { 140 | const transport = new StdioServerTransport(); 141 | await server.connect(transport); 142 | } 143 | 144 | main().catch((error) => { 145 | console.error("Server error:", error); 146 | process.exit(1); 147 | }); 148 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. 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