go-sdk

<!-- Autogenerated by weave; DO NOT EDIT --> # MCP Go SDK v0.3.0 [](https://codespaces.new/modelcontextprotocol/go-sdk) ***BREAKING CHANGES*** This version contains breaking changes. See the [release notes]( https://github.com/modelcontextprotocol/go-sdk/releases/tag/v0.3.0) for details. [](https://pkg.go.dev/github.com/modelcontextprotocol/go-sdk) This repository contains an unreleased implementation of the official Go software development kit (SDK) for the Model Context Protocol (MCP). > [!WARNING] > The SDK is not yet at v1.0.0 and may still be subject to incompatible API > changes. We aim to tag v1.0.0 in September, 2025. See > https://github.com/modelcontextprotocol/go-sdk/issues/328 for details. ## Design The design doc for this SDK is at [design.md](./design/design.md), which was initially reviewed at [modelcontextprotocol/discussions/364](https://github.com/orgs/modelcontextprotocol/discussions/364). Further design discussion should occur in [issues](https://github.com/modelcontextprotocol/go-sdk/issues) (for concrete proposals) or [discussions](https://github.com/modelcontextprotocol/go-sdk/discussions) for open-ended discussion. See [CONTRIBUTING.md](/CONTRIBUTING.md) for details. ## Package documentation The SDK consists of two importable packages: - The [`github.com/modelcontextprotocol/go-sdk/mcp`](https://pkg.go.dev/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`](https://pkg.go.dev/github.com/modelcontextprotocol/go-sdk/jsonrpc) package is for users implementing their own transports. ## Example In this example, an MCP client communicates with an MCP server running in a sidecar process: ```go package main import ( "context" "log" "os/exec" "github.com/modelcontextprotocol/go-sdk/mcp" ) func main() { ctx := context.Background() // Create a new client, with no features. client := mcp.NewClient(&mcp.Implementation{Name: "mcp-client", Version: "v1.0.0"}, nil) // Connect to a server over stdin/stdout transport := &mcp.CommandTransport{Command: exec.Command("myserver")} session, err := client.Connect(ctx, transport, nil) if err != nil { log.Fatal(err) } defer session.Close() // Call a tool on the server. params := &mcp.CallToolParams{ Name: "greet", Arguments: map[string]any{"name": "you"}, } res, err := session.CallTool(ctx, params) if err != nil { log.Fatalf("CallTool failed: %v", err) } if res.IsError { log.Fatal("tool failed") } for _, c := range res.Content { log.Print(c.(*mcp.TextContent).Text) } } ``` Here's an example of the corresponding server component, which communicates with its client over stdin/stdout: ```go package main import ( "context" "log" "github.com/modelcontextprotocol/go-sdk/mcp" ) type HiParams struct { Name string `json:"name" jsonschema:"the name of the person to greet"` } func SayHi(ctx context.Context, req *mcp.CallToolRequest, args HiParams) (*mcp.CallToolResult, any, error) { return &mcp.CallToolResult{ Content: []mcp.Content{&mcp.TextContent{Text: "Hi " + args.Name}}, }, nil, nil } func main() { // Create a server with a single tool. server := mcp.NewServer(&mcp.Implementation{Name: "greeter", Version: "v1.0.0"}, nil) mcp.AddTool(server, &mcp.Tool{Name: "greet", Description: "say hi"}, SayHi) // Run the server over stdin/stdout, until the client disconnects if err := server.Run(context.Background(), &mcp.StdioTransport{}); err != nil { log.Fatal(err) } } ``` The [`examples/`](/examples/) directory contains more example clients and servers. ## Acknowledgements Several existing Go MCP SDKs inspired the development and design of this official SDK, notably [mcp-go](https://github.com/mark3labs/mcp-go), authored by Ed Zynda. We are grateful to Ed as well as the other contributors to mcp-go, and to authors and contributors of other SDKs such as [mcp-golang](https://github.com/metoro-io/mcp-golang) and [go-mcp](https://github.com/ThinkInAIXYZ/go-mcp). Thanks to their work, there is a thriving ecosystem of Go MCP clients and servers. ## License This project is licensed under the MIT License - see the [LICENSE](./LICENSE) file for details.