1 Overview. JSON-RPC is a stateless, light-weight remote procedure call (RPC) protocol. Primarily this specification defines several data structures and the rules around their processing.

JSON-RPC messages MUST be UTF-8 encoded. The protocol currently defines two standard transport mechanisms for client-server communication: stdio, communication over standard in and standard out. Streamable HTTP. Clients SHOULD support stdio whenever possible.

Implementing JSON-RPC over stdio Protocol in MCP Station.JSON-RPC has a simple but well-defined spec. The shapes of requests and responses are fixed. from typing import Any, Optional from dataclasses import dataclass @.

stdio-json - JSON-RPC 2.0 messages using the same objects, method inventory, and numeric error codes as the A2A JSON-RPC binding (ProtoJSON serialization).

This specification applies to any transport carrying JSON-RPC 2.0 messages, including WebSocket, HTTP, stdio, and protocol frameworks such as the Model Context Protocol (MCP).

External Wire protocol — a JSON-RPC 2.0 over-stdio protocol, exposed by WireServer when running kimi --wire, allowing external programs to drive the agent and receive events.Every message is a single line of JSON conforming to the JSON-RPC 2.0 specification.

src/mcp/ protocol.ts # JSON-RPC 2.0 protocol parsing/serialization (pure functions, fully tested) tools.ts # MCP tool registration (reuses shared logic from core/loader.ts) server.ts # stdio server startup and request dispatch. Everything looked perf...

MCP servers use JSON-RPC 2.0 instead of HTTP REST. The key difference is standardized tool discovery — AI clients can automatically list all available tools and their parameters without reading documentation. MCP also supports STDIO transport...

Package Details. PURL. pkg:cargo/trusty-mcp-core spec. License. MulanPSL-2.0. First Release.

This article will demystify MCP by explaining exactly how it works at the protocol level, with practical examples you can run today. # # What MCP Actually Is **Think of MCP as JSON-RPC over stdio designed specifically for AI interactions.**