# MCP4Go MCP4Go is a Go implementation of the [Model Context Protocol (MCP)](https://modelcontextprotocol.io/introduction), designed to simplify the development of AI applications by abstracting away protocol complexities. ## Features - Complete MCP protocol implementation in pure Go - High-level abstractions for common MCP resources - Pluggable architecture for custom extensions - Comprehensive documentation and examples - Production-ready with robust error handling ## Installation MCP4Go requires Go 1.18 or later. Install it using Go modules: ```bash go get github.com/mcp4go/mcp4go ``` ## Getting Started To get started with MCP4Go, import the package in your Go application: ```go package main import ( "context" "fmt" "log" "os" "os/signal" "syscall" "time" "github.com/mcp4go/mcp4go/pkg/logger" "github.com/mcp4go/mcp4go/protocol" "github.com/mcp4go/mcp4go/server" "github.com/mcp4go/mcp4go/server/iface" "github.com/mcp4go/mcp4go/server/transport" _ "time/tzdata" // Load all time zones ) func main() { ctx, cancel := context.WithCancel(context.Background()) defer cancel() _logger := logger.DefaultLog // Listen for interrupt signals for graceful exit signalCh := make(chan os.Signal, 1) signal.Notify(signalCh, os.Interrupt, syscall.SIGTERM) go func() { <-signalCh _logger.Logf(ctx, logger.LevelWarn, "Received shutdown signal") cancel() }() type timeRequest struct { TimeZone string `json:"time_zone,omitempty" description:"time zone default is Asia/Shanghai"` } // Create standard input/output transport layer stdioTransport := transport.NewStdioTransport() // Create MCP server and configure options srv, cleanup, err := server.NewServer( stdioTransport, server.WithServerInfo(protocol.Implementation{ Name: "time-mcp", Version: "0.1.0", }), server.WithInstructions("Welcome to Time MCP! This server provides Time tools."), server.WithToolBuilder(iface.NewFunctionalToolsBuilder( iface.NewFunctionalToolWrapper( "time", "get current time", func(ctx context.Context, args timeRequest) ([]protocol.Content, error) { if args.TimeZone == "" { args.TimeZone = "Asia/Shanghai" } getTimezoneTime := func(_ context.Context, timeZone string) time.Time { if timeZone == "" { timeZone = "Asia/Shanghai" } loc, err := time.LoadLocation(timeZone) if err != nil { return time.Now() } return time.Now().In(loc) } currentTime := getTimezoneTime(ctx, args.TimeZone) return []protocol.Content{ protocol.NewTextContent(fmt.Sprintf("current time is %s", currentTime), nil), }, nil }), )), ) if err != nil { log.Printf("Failed to create server: %v\n", err) return } defer cleanup() // Start the server _logger.Logf(ctx, logger.LevelWarn, "Starting Time MCP server") if err := srv.Run(ctx); err != nil { _logger.Logf(ctx, logger.LevelError, "Server error: %v", err) return } _logger.Logf(ctx, logger.LevelWarn, "Server shutdown complete") } ``` ## Protocol Implementation MCP4Go provides a complete implementation of the Model Context Protocol with support for: - JSON-RPC communication - Resource lifecycle management - Prompt engineering - Tool definitions and invocations - Sampling parameters - Logging and diagnostics ## License This project is licensed under the MIT License ## Contributing Contributions are welcome! Please see our Contributing Guide for more information.