go-modelcontextprotocol

# go-modelcontextprotocol [](https://github.com/Warashi/go-modelcontextprotocol/actions/workflows/test.yaml) [](https://goreportcard.com/report/github.com/Warashi/go-modelcontextprotocol) [](https://pkg.go.dev/github.com/Warashi/go-modelcontextprotocol) `go-modelcontextprotocol` is a Go library that implements the Model Context Protocol (MCP). It provides a framework for building AI/LLM service backends with support for tools, resources, and various transport mechanisms. ## Project Structure - **mcp**: Core implementation of the Model Context Protocol with support for tools, resources, and server capabilities. - **jsonrpc2**: JSON-RPC 2.0 protocol implementation for client-server communication. - **jsonschema**: JSON schema validation tools for validating inputs and outputs. - **transport**: Transport layer implementations including stdio, SSE (Server-Sent Events), and pipe-based communication. - **router**: Flexible URI routing system with support for dynamic parameters and pattern matching. ## Usage ### Creating a Server To create a new server, use the `NewServer` function: ```go import ( "context" "log" "github.com/Warashi/go-modelcontextprotocol/mcp" ) func main() { // Create a new server with name and version server, err := mcp.NewServer("example", "1.0.0") if err != nil { log.Fatalf("Failed to create server: %v", err) } // Start the server using stdio transport ctx := context.Background() if err := server.ServeStdio(ctx); err != nil { log.Fatalf("Server failed: %v", err) } } ``` ### Adding Tools You can add tools to the server using the provided options: ```go import ( "context" "log" "github.com/Warashi/go-modelcontextprotocol/mcp" "github.com/Warashi/go-modelcontextprotocol/jsonschema" ) func main() { // Create a tool with a name, description, input schema, and handler function tool := mcp.NewToolFunc( "exampleTool", "An example tool", jsonschema.Object{}, func(ctx context.Context, input map[string]any) (map[string]any, error) { return map[string]any{"result": "success"}, nil }, ) // Create a server with the tool server, err := mcp.NewServer("example", "1.0.0", mcp.WithTool(tool)) if err != nil { log.Fatalf("Failed to create server: %v", err) } // Serve the server over stdin/stdout ctx := context.Background() if err := server.ServeStdio(ctx); err != nil { log.Fatalf("Server failed: %v", err) } } ``` ### Adding Resources You can add static resources and resource templates: ```go import ( "github.com/Warashi/go-modelcontextprotocol/mcp" ) // Add a static resource resource := mcp.Resource{ URI: "example://resource/doc", Name: "Example Resource", Description: "An example resource", MimeType: "text/plain", } // Add a resource template template := mcp.ResourceTemplate{ URITemplate: "example://resource/{id}", Name: "Example Template", Description: "A template for accessing resources by ID", MimeType: "text/plain", } // Create a resource reader to serve the resources reader := mcp.NewResourceReaderMux() // Create the server with resources server, err := mcp.NewServer("example", "1.0.0", mcp.WithResource(resource), mcp.WithResourceTemplate(template), mcp.WithResourceReader(reader), ) ``` ### Using HTTP/SSE Transport For web applications, you can use the SSE transport: ```go import ( "context" "log" "net/http" "github.com/Warashi/go-modelcontextprotocol/mcp" ) func main() { server, err := mcp.NewServer("example", "1.0.0") if err != nil { log.Fatalf("Failed to create server: %v", err) } // Create an SSE handler with a base URL handler, err := server.SSEHandler("http://localhost:8080/sse") if err != nil { log.Fatalf("Failed to create SSE handler: %v", err) } // Register the handler with your HTTP server // We need trailing slash to handle all under `/sse/` with SSE handler http.Handle("/sse/", handler) log.Fatal(http.ListenAndServe(":8080", nil)) } ``` ### Running Tests To run the tests, use the `go test` command: ```sh go test ./... ``` ## Server Implementations Using This Library - [mcp-server-pipecd](https://github.com/Warashi/mcp-server-pipecd) ## License This project is licensed under the MIT License. See the [LICENSE](./LICENSE) file for details.