the-protobuf-project/mcp

MCP

One schema, every surface. mcp is a spec-first protoc plugin that generates fully compliant Model Context Protocol servers straight from your .proto files — for Go, Rust, and C++ — so the definitions that already describe your APIs expose them to AI clients too.

This release brings full support for protocol version 2026-07-28.

Overview

Annotate your .proto files with MCP options and protoc-gen-mcp generates a Model Context Protocol server for each service — no hand-written glue, and no second schema to keep in sync.

The definitions you already maintain become:

• Tools → callable functions for agents
• Prompts → structured interaction templates
• Resources → retrievable context/data
• Elicitation → dynamic input flows
• Progress → incremental updates for long-running calls

The generated server implements the MCP specification at protocol version 2026-07-28 and delegates to your service implementation — in-process, or forwarded to a remote gRPC server. Your API stays strongly typed, and the proto remains the single source of truth.

Generated code builds on the official MCP SDKs — Go go-sdk v1.7+ and Rust rmcp 3.1+ (which also backs the C++ bridge).

This repository ships the plugin and the annotation .proto files. The Go runtime the generated code links against lives in