diff --git a/cmd/hppktool/cmd/encrypt.go b/cmd/hppktool/cmd/encrypt.go
index 4d480ba..7ee5906 100644
--- a/cmd/hppktool/cmd/encrypt.go
+++ b/cmd/hppktool/cmd/encrypt.go
@@ -20,7 +20,8 @@ import (
 var encryptCmd = &cobra.Command{
 	Use:   "encrypt",
 	Short: "encrypts a message from standard input",
-	Long:  `the message will first be SHA256 hashed and then encrypted using HPPK, unless -raw is specified`,
+	Long: `Encrypt a message with HPPK from standard input.
+The message is first SHA256 hashed, unless -raw is specified`,
 	Run: func(cmd *cobra.Command, args []string) {
 		silent, err := cmd.Flags().GetBool("silent")
 		if err != nil {
@@ -115,6 +116,6 @@ func init() {
 	// Cobra supports local flags which will only run when this command
 	// is called directly, e.g.:
 	// encryptCmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")
-	encryptCmd.Flags().StringP("pubkey", "p", "./id_hppk.pub", "the hppk public key file")
+	encryptCmd.Flags().StringP("pubkey", "p", "./id_hppk.pub", "the HPPK public key file")
 	encryptCmd.Flags().Bool("raw", false, "encrypt the raw message, the message length must not exceed 256 bytes")
 }
diff --git a/cmd/hppktool/cmd/keygen.go b/cmd/hppktool/cmd/keygen.go
index 7378c2d..081b61c 100644
--- a/cmd/hppktool/cmd/keygen.go
+++ b/cmd/hppktool/cmd/keygen.go
@@ -17,6 +17,7 @@ import (
 var keygenCmd = &cobra.Command{
 	Use:     "keygen [directory]",
 	Short:   "generate a hppk private/public key pair",
+	Long:    "Generate a HPPK private/public key pair with given order and save them to the specified directory.",
 	Example: "hppktool keygen /tmp\n" + "hppktool keygen /tmp --order 5",
 	Args:    cobra.ExactArgs(1),
 	Run: func(cmd *cobra.Command, args []string) {
diff --git a/cmd/hppktool/cmd/root.go b/cmd/hppktool/cmd/root.go
index 801b8c8..3e487a1 100644
--- a/cmd/hppktool/cmd/root.go
+++ b/cmd/hppktool/cmd/root.go
@@ -13,7 +13,8 @@ import (
 var rootCmd = &cobra.Command{
 	Use:   "hppktool",
 	Short: "HPPK key management tool",
-	Long:  `Key generation, signing, verification, and secret encryption tool for HPPK.`,
+	Long: `HPPK key management tool.
+HPPK key generation, signing, verification, and secret encryption.`,
 	// Uncomment the following line if your bare application
 	// has an action associated with it:
 	// Run: func(cmd *cobra.Command, args []string) { },
diff --git a/cmd/hppktool/cmd/sign.go b/cmd/hppktool/cmd/sign.go
index 017e56b..70d144c 100644
--- a/cmd/hppktool/cmd/sign.go
+++ b/cmd/hppktool/cmd/sign.go
@@ -20,7 +20,8 @@ import (
 var signCmd = &cobra.Command{
 	Use:   "sign",
 	Short: "sign a message from standard input",
-	Long:  `the message will first be SHA256 hashed and then encrypted using HPPK, unless -raw is specified`,
+	Long: `Sign a message with HPPK from standard input with a given public key.
+The message is first SHA256 hashed, unless -raw is specified`,
 	Run: func(cmd *cobra.Command, args []string) {
 		silent, err := cmd.Flags().GetBool("silent")
 		if err != nil {
diff --git a/cmd/hppktool/cmd/verify.go b/cmd/hppktool/cmd/verify.go
index 9fff039..c4d8853 100644
--- a/cmd/hppktool/cmd/verify.go
+++ b/cmd/hppktool/cmd/verify.go
@@ -19,7 +19,8 @@ import (
 var verifyCmd = &cobra.Command{
 	Use:   "verify",
 	Short: "verify a message from standard input",
-	Long:  `the message will first be SHA256 hashed and then be verified against using HPPK,unless -raw is specified`,
+	Long: `Verify a HPPK signed message from standard input against the signature file and public key.
+The message is first SHA256 hashed, unless -raw is specified`,
 	Run: func(cmd *cobra.Command, args []string) {
 		silent, err := cmd.Flags().GetBool("silent")
 		if err != nil {
@@ -128,7 +129,7 @@ func init() {
 	// Cobra supports local flags which will only run when this command
 	// is called directly, e.g.:
 	// verifyCmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")
-	verifyCmd.Flags().StringP("pubkey", "p", "./id_hppk.pub", "the hppk public key file")
-	verifyCmd.Flags().String("sigfile", "./sigfile", "the signed signature file")
-	verifyCmd.Flags().Bool("raw", false, "encrypt the raw message, the message length must not exceed 256 bytes")
+	verifyCmd.Flags().StringP("pubkey", "p", "./id_hppk.pub", "the HPPK public key file to verify against.")
+	verifyCmd.Flags().String("sigfile", "./sigfile", "the signed signature file.")
+	verifyCmd.Flags().Bool("raw", false, "encrypt the raw message, the message length must not exceed 256 bytes.")
 }