Community C++ MCP SDK

Build MCP clients and servers in C++.

A production-ready C++17 SDK with full protocol coverage across all MCP spec versions (2024-11-05 through DRAFT-2026-v1), cross-SDK conformance validation, and zero required runtime dependencies.

Get Started GitHub Conformance
⚡

Full Protocol

Tools, prompts, resources, sampling, tasks, progress, cancellation

✅

109/110 Server

448/448 client conformance against the official runner

📦

Zero Dependencies

C++17 public API. HTTP and OpenSSL are opt-in flags

🔒

OAuth 2.1

PKCE, DPoP, JWKS, bearer tokens — optional auth target

109/110
Server Tests Passed
448/448
Client Tests Passed
99%
Server Conformance

Easy to get started

A complete MCP server in under 15 lines of C++.

Builder Pattern

Chain .name(), .version(), .stdio() and register typed handlers. The builder compiles to a single .run() call — no boilerplate, no runtime dependency. 

#include <cxxmcp/peer.hpp>
#include <cxxmcp/run.hpp>

int main() {
    return mcp::ServerPeer::builder()
        .name("demo").version("1.0.0").stdio()
        .tool<mcp::protocol::Json, mcp::protocol::Json>(
            "echo", [](const mcp::protocol::Json& in) {
                return mcp::protocol::Json{{"echo", in}};
            })
        .run();
}

Typed DTOs with Reflection

Use CXXMCP_REFLECT to define request/response types. Zero-boilerplate serialization — the macro generates everything at compile time. 

struct SearchArgs {
    std::string query;
    int limit = 10;
    CXXMCP_REFLECT(SearchArgs, query, limit)
};

struct SearchResult {
    std::string title;
    std::string url;
    CXXMCP_REFLECT(SearchResult, title, url)
};

// Register a typed tool
.tool<SearchArgs, SearchResult>("search",
    [](const SearchArgs& args) {
        return SearchResult{"Found", "https://..."};
    })

Streamable HTTP Transport

Enable HTTP with a single CMake flag. The server supports SSE streaming, session management, and bearer token auth out of the box. 

# Build with HTTP transport
cmake -S . -B build -DCXXMCP_ENABLE_HTTP=ON
cmake --build build
// Server — listen on HTTP
ServerPeer::builder()
    .name("api").version("1.0.0")
    .streamable_http("0.0.0.0", 8080, "/mcp")
    .tool<Json, Json>("ping",
        [](const Json&) { return Json{{"ok", true}}; })
    .run();

Get cxxmcp

Install via your preferred method.

CMake FetchContent

Drop into any CMake project — no pre-install needed.

include(FetchContent)

vcpkg

Overlay port available in the repository.

vcpkg install cxxmcp-sdk --overlay-ports=ports/

System Install

Build, install, then find_package.

cmake --install build

Git Clone

Clone the repo and build directly.

git clone https://github.com/caomengxuan666/cxxmcp

Learn cxxmcp

Guides, references, and recipes for every use case.

Tutorials

Build servers, add HTTP, auth, typed tools, async tasks.

Concepts

Peer/Service architecture, transports, capability negotiation.

Cookbook

Copy-paste code snippets for common tasks.

Transports

stdio, process stdio, Streamable HTTP reference.

Auth

Bearer tokens, OAuth 2.1, DPoP, OpenSSL.

Migration

API mapping from TypeScript, Python, and Rust SDKs.

Roadmap

Current focus and longer-term goals.

Security

Vulnerability reporting and design decisions.