MCP Go SDK

This repository contains an implementation of the official Go software development kit (SDK) for the Model Context Protocol (MCP).

Package / Feature documentation

The SDK consists of several importable packages:

• The github.com/modelcontextprotocol/go-sdk/mcp package defines the primary APIs for constructing and using MCP clients and servers.
• The github.com/modelcontextprotocol/go-sdk/jsonrpc package is for users implementing their own transports.
• The github.com/modelcontextprotocol/go-sdk/auth package provides some primitives for supporting OAuth.
• The github.com/modelcontextprotocol/go-sdk/oauthex package provides extensions to the OAuth protocol, such as ProtectedResourceMetadata.

The SDK endeavors to implement the full MCP spec. The docs/ directory contains feature documentation, mapping the MCP spec to the packages above.

Version Compatibility

The following table shows which versions of the Go SDK support which versions of the MCP specification:

SDK Version	Latest MCP Spec	All Supported MCP Specs
v1.7.0+	2026-07-28	2026-07-28, 2025-11-25*, 2025-06-18, 2025-03-26, 2024-11-05
v1.4.0 - v1.6.1	2025-11-25*	2025-11-25*, 2025-06-18, 2025-03-26, 2024-11-05
v1.2.0 - v1.3.1	2025-11-25**	2025-11-25**, 2025-06-18, 2025-03-26, 2024-11-05
v1.0.0 - v1.1.0	2025-06-18	2025-06-18, 2025-03-26, 2024-11-05

* Client side OAuth has experimental support.

** Partial support for 2025-11-25 (client side OAuth and Sampling with tools not available).

The roots, sampling, and logging features are deprecated as of protocol version 2026-07-28 by SEP-2577. The SDK continues to support them for compatibility during the deprecation window (at least twelve months). See the individual feature documentation for migration guidance.

New releases of the SDK target only supported versions of Go. See https://go.dev/doc/devel/release#policy for more information.

Getting started

To get started creating an MCP server, create an mcp.Server instance, add features to it, and then run it over an mcp.Transport. For example, this server adds a single simple tool, and then connects it to clients over stdin/stdout:

package main

import (
	"context"
	"log"

	"github.com/modelcontextprotocol/go-sdk/mcp"
)

type Input struct {
	Name string `json:"name" jsonschema:"the name of the person to greet"`
}

type Output struct {
	Greeting string `json:"greeting" jsonschema:"the greeting to tell to the user"`
}

func SayHi(ctx context.Context, req *mcp.CallToolRequest, input Input) (
	*mcp.CallToolResult,
	Output,
	error,
) {
	return nil, Output{Greeting: "Hi " + input.Name}, nil
}