MCP C++ SDKModel Context Protocol for C++17

Build MCP servers and clients with full protocol support, dual-era WireCodec, and zero-cost abstractions.

Full Protocol

Tools, Resources, Prompts, Elicitation, MRTR, Tasks, Subscriptions — all MCP primitives supported across both protocol eras.

Stdio, Streamable HTTP, SSE, WebSocket, and InMemory transports. Easy to extend with custom transports.

Automatic version negotiation between 2025-11-25 (legacy) and 2026-07-28 (modern) protocol versions.

No GC, no heavy frameworks. Uses std::variant and smart pointers for type-safe, zero-cost abstractions.

215 tests, 113 conformance tests, OAuth PKCE, persistent storage backends, MessageFilter pipeline.

Windows (MSVC, clang-cl), Linux (GCC, Clang), macOS (Clang). Single CMake preset for all platforms.