c_mcp_sdk

This is a C implementation of the Model Context Protocol (MCP) SDK, designed to help developers create MCP servers in C. The project provides a lightweight, efficient framework for building MCP-compliant servers with minimal dependencies.

Implemented specifications

• Model Context Protocol
• JSON-RPC 2.0

Project Purpose

The Model Context Protocol is a specification for AI assistants to communicate with external tools and data sources. This C SDK focuses on implementing the MCP protocol itself, providing the core functionality needed to create MCP-compliant applications.

Protocol Implementation

The c_mcp_sdk library is specifically designed to handle MCP protocol implementation, including:

• JSON-RPC message parsing and serialization
• MCP-specific message types and structures
• Tool registration and request processing
• Efficient memory management

Transportation Layer

While the library focuses on protocol implementation, there are no limitations on transportation implementations. The SDK provides:

STDIO Support: Built-in support for reading and parsing MCP messages over standard input/output streams, making it easy to create command-line MCP servers.

HTTP Transportation: For HTTP-based MCP servers, we recommend using:

• cesanta/mongoose - Lightweight, portable HTTP server
• mbedtls - TLS/SSL library for secure connections

We will provide examples demonstrating HTTP server implementation using these libraries to show how to integrate the MCP protocol with HTTP transportation.

Included third-party libraries

• pdjson is used for JSON parsing.

Build

cmake -B build
cmake --build build

Demo

npx -y @modelcontextprotocol/inspector ./build/demo/simple_datetime_mcp