kovidgoyal/kitty · error

%s is not a valid contrast value

Error message

%s is not a valid contrast value

What it means

The `set-contrast` command only accepts the literal strings `normal` (mapped to uint32 0) and `high` (mapped to uint32 1). Any other string falls into the default branch and is rejected.

Source

Thrown at kittens/desktop_ui/main.go:134

	})
	parent.AddSubCommand(&cli.Command{
		Name:             "set-contrast",
		ShortDescription: "Change the contrast. Can be high or normal.",
		Usage:            " high|normal",
		Run: func(cmd *cli.Command, args []string) (rc int, err error) {
			if len(args) != 1 {
				cmd.ShowHelp()
				return 1, fmt.Errorf("must specify the new contrast value")
			}

			var v dbus.Variant
			switch args[0] {
			case "normal":
				v = dbus.MakeVariant(uint32(0))
			case "high":
				v = dbus.MakeVariant(uint32(1))
			default:
				return 1, fmt.Errorf("%s is not a valid contrast value", args[0])
			}
			err = set_variant_setting(PORTAL_APPEARANCE_NAMESPACE, PORTAL_CONTRAST_KEY, v, false)
			return utils.IfElse(err == nil, 0, 1), err
		},
	})
	st := parent.AddSubCommand(&cli.Command{
		Name:             "set-setting",
		ShortDescription: "Change an arbitrary setting",
		Usage:            " key [value]",
		HelpText:         "Set an arbitrary setting. If you want to set the color-scheme use the dedicated command for it. Use this command with care as it does no validation for the type of value. The syntax for specifying values is described at: :link:`the glib docs <https://docs.gtk.org/glib/gvariant-text-format.html>`. Leaving out the value or specifying an empty value, will delete the setting.",
		Run: func(cmd *cli.Command, args []string) (rc int, err error) {
			val := ""
			if len(args) < 1 {
				cmd.ShowHelp()
				return 1, fmt.Errorf("must specify the key")
			}
			if len(args) > 1 {
				val = args[1]

View on GitHub (pinned to 6d5d0c4406)

Solutions

1. Use exactly `normal` or `high` as the contrast value
2. If forwarding from a script, map your internal values to these two strings first

Example fix

# before
kitten desktop-ui set-contrast 1
# after
kitten desktop-ui set-contrast high

valid := map[string]bool{"normal": true, "high": true}
if !valid[args[0]] { /* reject before calling */ }

func isContrastValue(s string) bool { return s == "normal" || s == "high" }

When it happens

Trigger: Passing anything other than `normal` or `high`, e.g. `set-contrast low`, `set-contrast 1`, `set-contrast TRUE`.

Common situations: Users guessing numeric or boolean values; scripts forwarding values from other tools that use different vocabularies.

Related errors

• must specify the new contrast value
• must specify the key
• no arguments allowed
• No kitten named {original_kitten_name}
• This should be run as kitten ssh

AI-assisted analysis of kovidgoyal/kitty@6d5d0c4406 (2026-08-27). Data as JSON: /api/errors/93553590a2ff8f96. Report an issue: GitHub.