Official MCP Go SDK

Overview

The official MCP Go SDK is the Model Context Protocol project's Go implementation for building MCP clients and servers. The repository is maintained by the modelcontextprotocol organization in collaboration with Google and provides importable packages for MCP APIs, JSON-RPC transport work, OAuth primitives, and protected-resource metadata extensions.

This entry covers the official SDK. The catalog may also include community Go SDKs such as mark3labs/mcp-go; those remain viable alternatives, but this source is the official SDK maintained under the Model Context Protocol project.

Core Capabilities

Quick Start

Install the module:

go get github.com/modelcontextprotocol/go-sdk

A minimal server creates an MCP server, registers a typed tool, and runs over stdio:

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"`
}

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

func main() {
    server := mcp.NewServer(&mcp.Implementation{Name: "greeter", Version: "v1.0.0"}, nil)
    mcp.AddTool(server, &mcp.Tool{Name: "greet", Description: "say hi"}, SayHi)
    if err := server.Run(context.Background(), &mcp.StdioTransport{}); err != nil {
        log.Fatal(err)
    }
}

MCP Fit

Choose the official Go SDK when a Go application needs to track current MCP specification behavior closely, use official protocol types, or build clients and servers against the same project that maintains the protocol. It is a good fit for infrastructure teams, platform teams, and Go service owners adding MCP support to existing systems.

Because this is a protocol SDK, production safety depends on the handlers and transports you build. Treat each tool as an API endpoint and each resource as a model-visible data exposure.

Use Cases

• Add an MCP server to a Go service or CLI.
• Build an MCP client or test harness in Go.
• Implement a custom JSON-RPC transport around official MCP types.
• Prototype OAuth-protected MCP resources.
• Track compatibility with the current MCP specification version matrix.
• Compare official SDK behavior against community Go MCP SDKs.

Source Review

Verified on 2026-06-18:

• The upstream README identifies the repository as the official Go SDK for the Model Context Protocol.
• The README lists importable packages for mcp, jsonrpc, auth, and oauthex, plus a version compatibility matrix for MCP specification support.
• go.mod declares module path github.com/modelcontextprotocol/go-sdk.
• The license file documents the project's licensing transition to Apache-2.0 for new code/spec contributions, MIT for unrelicensed existing code, and CC-BY-4.0 for documentation contributions excluding specifications.
• pkg.go.dev resolves documentation for github.com/modelcontextprotocol/go-sdk.

Safety and Privacy

The official SDK handles protocol mechanics; it does not make your tool surface safe by itself. Validate arguments, check user permissions, limit side effects, sanitize errors, and avoid exposing sensitive resources by default.

Network transports and OAuth flows should be threat-modeled before production. Document what data is visible to MCP clients, model providers, logs, traces, and resource servers for each deployment.

Duplicate Check

Checked current content/mcp/, content/tools/, content/skills/, open pull requests, and repository-wide content for modelcontextprotocol/go-sdk, official MCP Go SDK, Model Context Protocol Go SDK, Go MCP server official SDK, Go MCP client official SDK, MCP JSON-RPC Go, and MCP OAuth Go SDK. Existing work may cover the community mark3labs/mcp-go SDK, but no dedicated official Go SDK entry, exact source URL duplicate, target file, or open duplicate PR was found.