"""Application error types exposed at architectural boundaries."""


class SD15Error(Exception):
    """Base application error."""


class ConfigError(SD15Error):
    """Configuration is invalid or incomplete."""


class InvalidRequestError(SD15Error):
    """A tool request is invalid."""


class InvalidImageError(InvalidRequestError):
    """An input is not a supported image."""


class GenerationError(SD15Error):
    """The inference backend failed."""