Generate API Tools from C++ Controllers

oatpp-mcp is Anthropic's Model Context Protocol implementation for the Oat++ C++ web framework. Its standout feature is automatically generating MCP tools from an existing ApiController, so an LLM can query your REST API without you hand-writing separate tool definitions.

Use it when you're building a C++ web service with Oat++ and want to expose it to an LLM via MCP - either by auto-generating tools straight from your API controllers, or by manually registering custom prompts, resources, and tools. It supports both STDIO transport (for local process-based MCP clients) and HTTP SSE transport (for serving multiple remote clients over your existing HTTP router). Do not use it if your project isn't built on Oat++ - this is a framework-specific integration, not a standalone or language-agnostic MCP server.

• Autogenerated API tools: generate MCP tools directly from an ApiController, letting an LLM query your API without manual tool authoring (see the linked tutorial and the example-crud project's add_mcp_server branch).
• Prompts: register custom MCP prompts (e.g. a CodeReview prompt) via server.addPrompt(...).
• Resources: register MCP resources (e.g. a File resource) via server.addResource(...).
• Tools: register custom MCP tools (e.g. a Logger tool) via server.addTool(...).
• Transport: serve over STDIO (server.stdioListen()) or HTTP SSE by adding server.getSseController() to your existing HTTP router.

Requires the main oatpp module installed first. Then build and install this module:

mkdir build && cd build
cmake ..
make install

Example usage (STDIO transport):

oatpp::mcp::Server server;
server.addPrompt(std::make_shared<prompts::CodeReview>());
server.addResource(std::make_shared<resource::File>());
server.addTool(std::make_shared<tools::Logger>());
server.stdioListen();

Note: redirect Oat++'s own logging to a different stream (e.g. a file via a custom Logger) when serving over STDIO, since STDIO is reserved for MCP protocol messages. A working example is available in the test suite at /test/oatpp-mcp/app/ServerTest.cpp.

C++ developers building web services on Oat++ who want to expose their REST APIs (or custom prompts/resources/tools) to LLMs via MCP without switching languages or frameworks.