check args before use in mcp

if no subcommands given print usage

Author: burmudar

cmd/src/mcp.go

@@ -16,32 +16,43 @@ import (
 func init() {
 	flagSet := flag.NewFlagSet("mcp", flag.ExitOnError)
 	commands = append(commands, &command{
-		flagSet: flagSet,
-		handler: mcpMain,
+		flagSet:   flagSet,
+		handler:   mcpMain,
+		usageFunc: mcpUsage,
 	})
 }
+
+func mcpUsage() {
+	fmt.Println("The 'mcp' command exposes MCP tools as subcommands for agents to use.")
+	fmt.Println("\nUSAGE:")
+	fmt.Println("  src mcp list-tools              List available tools")
+	fmt.Println("  src mcp <tool-name> schema      View the input/output schema of a tool")
+	fmt.Println("  src mcp <tool-name> <flags>     Invoke a tool with the given flags")
+	fmt.Println("  src mcp <tool-name> -h          List the available flags of a tool")
+}
+
 func mcpMain(args []string) error {
 	fmt.Println("NOTE: This command is still experimental")
 	tools, err := mcp.LoadDefaultToolDefinitions()
 	if err != nil {
 		return err
 	}
 
+	if len(args) == 0 {
+		mcpUsage()
+		return nil
+	}
+
 	subcmd := args[0]
 	if subcmd == "list-tools" {
 		fmt.Println("The following tools are available:")
 		for name := range tools {
-			fmt.Printf(" • %s\n", name)
+			fmt.Printf("  %s\n", name)
 		}
 		fmt.Println("\nUSAGE:")
-		fmt.Printf(" • Invoke a tool\n")
-		fmt.Printf("     src mcp <tool-name> <flags>\n")
-		fmt.Printf("\n • View the Input / Output Schema of a tool\n")
-		fmt.Printf("     src mcp <tool-name> schema\n")
-		fmt.Printf("\n • List the available flags of a tool\n")
-		fmt.Printf("     src mcp <tool-name> -h\n")
-		fmt.Printf("\n • View the Input / Output Schema of a tool\n")
-		fmt.Printf("     src mcp <tool-name> schema\n")
+		fmt.Println("  src mcp <tool-name> schema      View the input/output schema of a tool")
+		fmt.Println("  src mcp <tool-name> <flags>     Invoke a tool with the given flags")
+		fmt.Println("  src mcp <tool-name> -h          List the available flags of a tool")
 		return nil
 	}