diff --git a/cmd/completion.go b/cmd/completion.go
new file mode 100644
index 0000000..6ead4b8
--- /dev/null
+++ b/cmd/completion.go
@@ -0,0 +1,37 @@
+package cmd
+
+import (
+	"fmt"
+	"io"
+	"os"
+
+	"github.com/spf13/cobra"
+)
+
+var completionCmd = &cobra.Command{
+	Use:                   "completion [bash|zsh|fish|powershell]",
+	Short:                 "Generate shell completion scripts",
+	Long:                  "Generate shell completion scripts for fgj.",
+	Args:                  cobra.MatchAll(cobra.ExactArgs(1), cobra.OnlyValidArgs),
+	ValidArgs:             []string{"bash", "zsh", "fish", "powershell"},
+	DisableFlagsInUseLine: true,
+	RunE: func(cmd *cobra.Command, args []string) error {
+		var out io.Writer = os.Stdout
+		switch args[0] {
+		case "bash":
+			return rootCmd.GenBashCompletion(out)
+		case "zsh":
+			return rootCmd.GenZshCompletion(out)
+		case "fish":
+			return rootCmd.GenFishCompletion(out, true)
+		case "powershell":
+			return rootCmd.GenPowerShellCompletionWithDesc(out)
+		default:
+			return fmt.Errorf("unsupported shell: %s", args[0])
+		}
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(completionCmd)
+}
diff --git a/cmd/manpages.go b/cmd/manpages.go
new file mode 100644
index 0000000..5fc7e10
--- /dev/null
+++ b/cmd/manpages.go
@@ -0,0 +1,49 @@
+package cmd
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/spf13/cobra"
+	"github.com/spf13/cobra/doc"
+)
+
+var manpagesCmd = &cobra.Command{
+	Use:   "manpages",
+	Short: "Generate manpages",
+	Long:  "Generate manpages for fgj commands.",
+	RunE: func(cmd *cobra.Command, args []string) error {
+		dir, _ := cmd.Flags().GetString("dir")
+		if dir == "" {
+			return fmt.Errorf("directory is required")
+		}
+
+		if err := os.MkdirAll(dir, 0755); err != nil {
+			return fmt.Errorf("failed to create %s: %w", dir, err)
+		}
+
+		absDir, err := filepath.Abs(dir)
+		if err != nil {
+			return fmt.Errorf("failed to resolve %s: %w", dir, err)
+		}
+
+		header := &doc.GenManHeader{
+			Title:   "FGJ",
+			Section: "1",
+		}
+
+		if err := doc.GenManTree(rootCmd, header, absDir); err != nil {
+			return fmt.Errorf("failed to generate manpages: %w", err)
+		}
+
+		fmt.Printf("Manpages generated in %s\n", absDir)
+		return nil
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(manpagesCmd)
+	manpagesCmd.Flags().String("dir", "", "Output directory for manpages")
+	_ = manpagesCmd.MarkFlagRequired("dir")
+}