diff --git a/cmd/config/config.go b/cmd/config/config.go
index 5cb350ca..291fbe40 100644
--- a/cmd/config/config.go
+++ b/cmd/config/config.go
@@ -96,6 +96,13 @@ func run() func(*cobra.Command, []string) error {
 				return errors.NewError("flag needs an argument: --set")
 			}
 
+			for i := 0; i < len(args)-1; i += 2 {
+				_, ok := cliflags.AllFlagsHelp()[args[i]]
+				if !ok {
+					return newErr(args[i])
+				}
+			}
+
 			rawConfig, v, err := getRawConfig()
 			if err != nil {
 				return err
@@ -122,6 +129,11 @@ func run() func(*cobra.Command, []string) error {
 
 			return writeConfig(configFile, v, setKeyFn)
 		case viper.IsSet(UnsetFlag):
+			_, ok := cliflags.AllFlagsHelp()[viper.GetString(UnsetFlag)]
+			if !ok {
+				return newErr(viper.GetString(UnsetFlag))
+			}
+
 			config, v, err := getConfig()
 			if err != nil {
 				return err
@@ -133,7 +145,12 @@ func run() func(*cobra.Command, []string) error {
 				}
 			}
 
-			return writeConfig(config, v, unsetKeyFn)
+			// TODO: show successful output
+
+			err = writeConfig(config, v, unsetKeyFn)
+			if err != nil {
+				return err
+			}
 		default:
 			return cmd.Help()
 		}
@@ -234,3 +251,16 @@ func writeConfig(
 
 	return nil
 }
+
+func newErr(flag string) error {
+	err := errors.NewError(
+		fmt.Sprintf(
+			`{
+				"message": "%s is not a valid configuration option"
+			}`,
+			flag,
+		),
+	)
+
+	return errors.NewError(output.CmdOutputError(flag, err))
+}