cheapo/cmd/cheapo/mcp.go

package main

import (
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/spf13/cobra"

	"gogs.netdome.biz/paul/cheapo/internal/mcpserver"
)

// version is the value reported to MCP clients; overridable via -ldflags.
var version = "dev"

func mcpCmd() *cobra.Command {
	var (
		httpAddr       string
		httpPath       string
		token          string
		stateless      bool
		sessionTimeout time.Duration
	)
	cmd := &cobra.Command{
		Use:   "mcp",
		Short: "MCP server (HTTP or stdio) for agents and MCP clients",
		Long: `Exposes the free games data as an MCP server.

Tools:
  list_offers  Mirrors "cheapo list" — mode: free (default), upcoming,
               deals; plus store, country, locale

The server is stateless: every call returns the full current state;
deduplication ("what is new?") is the client's job.

Without --http the server runs over stdio (for clients that start the
binary themselves). With --http it runs as an HTTP service (Streamable
HTTP) — the mode for remote clients, multiple users and monitoring.

Examples:
  cheapo mcp --http 127.0.0.1:8080
  cheapo mcp --http 0.0.0.0:8080 --token "$CHEAPO_MCP_TOKEN"
  cheapo mcp                      # stdio

Region/locale/stores come from the global flags (--country, --locale,
--store) and apply as defaults for the tool calls.`,
		Args: cobra.NoArgs,
		RunE: func(cmd *cobra.Command, _ []string) error {
			ctx, stop := signal.NotifyContext(cmd.Context(), syscall.SIGINT, syscall.SIGTERM)
			defer stop()

			// CHEAPO_MCP_TOKEN may also come from a .env file (godotenv);
			// real environment variables take precedence.
			loadEnv()

			srv := mcpserver.New(mcpserver.Options{
				Store:   flagStore,
				Country: flagCountry,
				Locale:  flagLocale,
				Version: version,
			})

			if httpAddr == "" {
				return srv.Run(ctx)
			}
			if token == "" {
				token = os.Getenv("CHEAPO_MCP_TOKEN")
			}
			return srv.RunHTTP(ctx, httpAddr, mcpserver.HTTPOptions{
				Path:           httpPath,
				Token:          token,
				Stateless:      stateless,
				SessionTimeout: sessionTimeout,
			})
		},
	}

	cmd.Flags().StringVar(&httpAddr, "http", "", "HTTP address (e.g. 127.0.0.1:8080); empty = stdio")
	cmd.Flags().StringVar(&httpPath, "path", "/mcp", "HTTP path of the MCP endpoint")
	cmd.Flags().StringVar(&token, "token", "", "Bearer token for HTTP (default: $CHEAPO_MCP_TOKEN)")
	cmd.Flags().BoolVar(&stateless, "stateless", false, "HTTP without sessions (for proxies/load balancers)")
	cmd.Flags().DurationVar(&sessionTimeout, "session-timeout", 30*time.Minute, "Idle timeout for HTTP sessions")
	return cmd
}