cxxmcp

cxxmcp is a C++17 SDK for the Model Context Protocol. It lets you build MCP servers and clients that embed directly into native C++ applications, with typed protocol models, tool, prompt and resource registries on the server side, and HTTP, stdio and process-stdio clients with async helpers on the client side.

Transports include stdio, process stdio, Streamable HTTP with stateful sessions, legacy SSE compatibility and WebSocket with auto-reconnect. Protocol coverage lists tools, prompts, resources and templates, completion, logging, roots, sampling, elicitation, task lifecycle, progress and cancellation, plus raw JSON-RPC escape hatches for vendor extensions. The project says it is validated against the official modelcontextprotocol/conformance runner and reports 109 of 110 server checks passing, against 48 of 95 for the RMCP Rust SDK in its own comparison table. It can be consumed through CMake find_package, Conan 2, a vcpkg overlay, FetchContent or CPM, and the quick start builds an echo server in about a dozen lines.