kovidgoyal/kitty · error · KeyError

{key} is not a valid color name

Error message

{key} is not a valid color name

What it means

set-tab-color parses key=value specs where key must be one of the valid color names ('active', 'inactive', 'default', etc.). Unknown keys raise KeyError.

Source

Thrown at kitty/rc/set_tab_color.py:24

from kitty.rgb import to_color

from .base import MATCH_TAB_OPTION, ArgsType, Boss, ParsingOfArgsFailed, PayloadGetType, PayloadType, RCOptions, RemoteCommand, ResponseType, Window

if TYPE_CHECKING:
    from kitty.cli_stub import SetTabColorRCOptions as CLIOptions


valid_color_names = frozenset('active_fg active_bg inactive_fg inactive_bg'.split())


def parse_colors(args: ArgsType) -> dict[str, int | None]:
    ans: dict[str, int | None] = {}
    for spec in args:
        key, val = spec.split('=', 1)
        key = key.lower()
        if key.lower() not in valid_color_names:
            raise KeyError(f'{key} is not a valid color name')
        if val.lower() == 'none':
            col: int | None = None
        else:
            q = to_color(val, validate=True)
            if q is not None:
                col = int(q)
        ans[key.lower()] = col
    return ans


class SetTabColor(RemoteCommand):
    protocol_spec = __doc__ = """
    colors+/dict.colors: An object mapping names to colors as 24-bit RGB integers. A color value of null indicates it should be unset.
    match/str: Which tab to change the color of
    self/bool: Boolean indicating whether to use the tab of the window the command is run in
    """

    short_desc = 'Change the color of the specified tabs in the tab bar'

View on GitHub (pinned to 6d5d0c4406)

Solutions

1. Use valid keys only (e.g. color=..., or active/inactive as documented in @set-tab-color --help)
2. Check valid_color_names in kitty/rc/set_tab_color.py for your version

Example fix

# before
kitten @set-tab-color active-background=red
# after
kitten @set-tab-color color=red

from kitty.rc.set_tab_color import valid_color_names
assert key.lower() in valid_color_names

def is_valid_color_name(k: str, valid) -> bool: return k.lower() in valid

except KeyError as e: print('unknown color slot:', e)

When it happens

Trigger: kitten @set-tab-color foo=red, or a misspelled key such as 'activ=red'.

Common situations: Scripts guessing at color slot names; kitty versions differ in supported slots.

Related errors

• Unknown type_of_input: {type_of_input}
• Unknown keys in multicell_command:
• The value {x} is not a known choice
• The value {val} is not a valid choice for progress_bar
• The value {val} is not a valid choice for scrollbar

AI-assisted analysis of kovidgoyal/kitty@6d5d0c4406 (2026-08-27). Data as JSON: /api/errors/43b6a60beb32ff17. Report an issue: GitHub.