chore: import upstream snapshot with attribution

examples/mcp/documented/main.go

@@ -0,0 +1,137 @@
+// Package main demonstrates how to document your service handlers for better
+// AI agent integration using endpoint metadata.
+//
+// Services register descriptions with their endpoints, and the MCP gateway
+// reads these descriptions from the registry to generate rich tool descriptions.
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+
+	"go-micro.dev/v6"
+	"go-micro.dev/v6/gateway/mcp"
+	"go-micro.dev/v6/server"
+)
+
+// User represents a user in the system
+type User struct {
+	ID    string `json:"id" description:"User's unique identifier (UUID format)"`
+	Name  string `json:"name" description:"User's full name"`
+	Email string `json:"email" description:"User's email address"`
+	Age   int    `json:"age,omitempty" description:"User's age (optional)"`
+}
+
+// GetUserRequest is the request for getting a user
+type GetUserRequest struct {
+	ID string `json:"id" description:"User ID to retrieve"`
+}
+
+// GetUserResponse is the response containing user data
+type GetUserResponse struct {
+	User *User `json:"user" description:"The requested user object"`
+}
+
+// CreateUserRequest is the request for creating a user
+type CreateUserRequest struct {
+	Name  string `json:"name" description:"User's full name (required)"`
+	Email string `json:"email" description:"User's email address (required)"`
+	Age   int    `json:"age,omitempty" description:"User's age (optional)"`
+}
+
+// CreateUserResponse contains the newly created user
+type CreateUserResponse struct {
+	User *User `json:"user" description:"The newly created user"`
+}
+
+// Users service handles user-related operations
+type Users struct {
+	users map[string]*User
+}
+
+// GetUser retrieves a user by ID from the database. Returns full profile including email, name, and preferences. If the user doesn't exist, an error is returned.
+//
+// @example {"id": "user-1"}
+func (u *Users) GetUser(ctx context.Context, req *GetUserRequest, rsp *GetUserResponse) error {
+	user, exists := u.users[req.ID]
+	if !exists {
+		return fmt.Errorf("user not found: %s", req.ID)
+	}
+
+	rsp.User = user
+	return nil
+}
+
+// CreateUser creates a new user in the system. Validates the user data and creates a new profile. Name and email are required fields, while age is optional. Email must be unique across all users.
+//
+// @example {"name": "Alice Smith", "email": "alice@example.com", "age": 30}
+func (u *Users) CreateUser(ctx context.Context, req *CreateUserRequest, rsp *CreateUserResponse) error {
+	// Validate input
+	if req.Name == "" || req.Email == "" {
+		return fmt.Errorf("name and email are required")
+	}
+
+	// Generate ID (simplified for example)
+	id := fmt.Sprintf("user-%d", len(u.users)+1)
+
+	user := &User{
+		ID:    id,
+		Name:  req.Name,
+		Email: req.Email,
+		Age:   req.Age,
+	}
+
+	u.users[id] = user
+	rsp.User = user
+
+	return nil
+}
+
+func main() {
+	// Create service
+	service := micro.NewService("users",
+		micro.Address(":9090"),
+		// Start MCP gateway alongside the service
+		mcp.WithMCP(":3000"),
+	)
+
+	service.Init()
+
+	// Register handler with pre-populated test data.
+	// Documentation is automatically extracted from method comments.
+	// Use WithEndpointScopes to declare required auth scopes per endpoint.
+	if err := service.Handle(
+		&Users{
+			users: map[string]*User{
+				"user-1": {ID: "user-1", Name: "John Doe", Email: "john@example.com", Age: 25},
+				"user-2": {ID: "user-2", Name: "Jane Smith", Email: "jane@example.com", Age: 30},
+			},
+		},
+		server.WithEndpointScopes("Users.GetUser", "users:read"),
+		server.WithEndpointScopes("Users.CreateUser", "users:write"),
+	); err != nil {
+		log.Fatal(err)
+	}
+
+	log.Println("Users service starting...")
+	log.Println("Service: users")
+	log.Println("Endpoints:")
+	log.Println("  - Users.GetUser")
+	log.Println("  - Users.CreateUser")
+	log.Println("MCP Gateway: http://localhost:3000")
+	log.Println("")
+	log.Println("Test with:")
+	log.Println("  curl http://localhost:3000/mcp/tools")
+	log.Println("")
+	log.Println("Or add to Claude Code:")
+	log.Println(`  "users-service": {`)
+	log.Println(`    "command": "micro",`)
+	log.Println(`    "args": ["mcp", "serve"]`)
+	log.Println(`  }`)
+
+	// Run service
+	if err := service.Run(); err != nil {
+		log.Fatal(err)
+	}
+}