Demonstrates a basic JSON-RPC client and server implementation using Node.js.
Demonstrates a basic JSON-RPC client and server implementation using Node.js. Exposed over MCP by the json mcp server, that capability becomes something an assistant can invoke while it works, not something you go and do afterwards.
This repository contains a simple, beginner-friendly example of an MCP-inspired JSON‑RPC client and server implemented in JavaScript. The project demonstrates a basic communication flow using Node.js's built‑in modules without any external dependencies.
Everything the assistant can do here goes through one of these:
initialize — Returns a basic capabilities object (advertising an "echo" tool)echo — Echoes back the parameters provided by the clientserver.js — The JSON‑RPC server implementationclient.js — The JSON‑RPC client implementationInstallation goes through your MCP client rather than a global install: point it at @smithery/cli on npm and it is fetched when the client starts. The copy-paste blocks for Claude Desktop, Claude Code and Cursor are further down this page.
Among the developer tooling options, the useful question is rarely "what can it do" but "what does it cost you to run" — permissions, credentials, and how much of your context its toolset consumes. JSON's toolset — initialize, echo, server.js and 1 more — is a fair guide to whether it matches your workflow. It is maintained by melvincarvalho; worth a glance at recent repository activity before you build anything load-bearing on it.
This entry was verified against JSON's own documentation before publication; SyncDev keeps the directory reviewed rather than auto-generated.
| Tool | What it does |
|---|---|
| initialize | Returns a basic capabilities object (advertising an "echo" tool). |
| echo | Echoes back the parameters provided by the client. |
| server.js | The JSON‑RPC server implementation. |
| client.js | The JSON‑RPC client implementation. |
{
"mcpServers": {
"json-rpc-client-and-server-example": {
"command": "npx",
"args": ["-y", "@smithery/cli"]
}
}
}Add to claude_desktop_config.json, then restart Claude Desktop.
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