CoplayDev/unity-mcp · error · ValueError

{context} must be a list or hex string

Error message

{context} must be a list or hex string

What it means

Raised by _normalize_color (texture.py:143) when the value is not None, not a (hex) string, not a dict, and not a list/tuple — i.e. an unsupported scalar type such as an int, float, or bool. The 'context' label names the field. After a non-# string is JSON-parsed it may become one of these unsupported types, hitting the final fallback.

Source

Thrown at Server/src/cli/commands/texture.py:143

            except (TypeError, ValueError):
                raise ValueError(f"{context} dict values must be numeric, got {value}")
        raise ValueError(f"{context} dict must have 'r', 'g', 'b' keys, got {list(value.keys())}")

    if isinstance(value, (list, tuple)):
        if len(value) == 3:
            value = list(value) + [1.0 if _is_normalized_color(value) else 255]
        if len(value) == 4:
            try:
                if _is_normalized_color(value):
                    return [int(round(float(c) * 255)) for c in value]
                return [int(c) for c in value]
            except (TypeError, ValueError):
                raise ValueError(
                    f"{context} values must be numeric, got {value}")
        raise ValueError(
            f"{context} must have 3 or 4 components, got {len(value)}")

    raise ValueError(f"{context} must be a list or hex string")


def _normalize_palette(value: Any, context: str) -> list[list[int]]:
    if value is None:
        return []
    if isinstance(value, str):
        value = try_parse_json(value, context)
    if not isinstance(value, list):
        raise ValueError(f"{context} must be a list of colors")
    return [_normalize_color(color, f"{context} item") for color in value]


def _normalize_pixels(value: Any, width: int, height: int, context: str) -> list[list[int]] | str:
    if value is None:
        raise ValueError(f"{context} is required")
    if isinstance(value, str):
        if value.startswith("base64:"):
            return value

View on GitHub (pinned to c21bf496bc)

Solutions

1. Pass a color as a hex string (#RRGGBB), a [r,g,b] list, or an {r,g,b} dict.
2. If you meant grayscale, expand it to a 3- or 4-element array (e.g. [128,128,128]).
3. Ensure JSON color arguments parse to an array or object, not a scalar.

Example fix

# before
unity-mcp texture create Assets/Tex.png --color '128'

# after
unity-mcp texture create Assets/Tex.png --color '[128,128,128]'

# Python - accept only supported color shapes before _normalize_color
ok = value is None or isinstance(value, str) or isinstance(value, dict) or isinstance(value, (list, tuple))
if not ok:
    raise ValueError(f"{context} must be a list or hex string")

def is_color_shape(v) -> bool: return v is None or isinstance(v,(str,dict,list,tuple))

try:
    color = _normalize_color(value, context)
except ValueError as e:
    print_error(str(e)); sys.exit(1)

When it happens

Trigger: Passing --color '128' (a bare integer), --color '1.0', or a JSON string that parses to a scalar. Applies to any color argument (color, palette item, pixel, set-pixels color).

Common situations: Passing a grayscale int expecting it to expand; a JSON string that evaluates to a number instead of an array/object; a boolean where a color was expected.

Related errors

• Invalid hex color: {value}
• {context} is required
• {context} dict values must be numeric, got {value}
• {context} values must be numeric, got {value}
• {context} must have 3 or 4 components, got {len(value)}

AI-assisted analysis of CoplayDev/unity-mcp@c21bf496bc (2026-08-13). Data as JSON: /api/errors/d8f96ba0cda96400. Report an issue: GitHub.