ReadonlymessageHuman-readable error message; never empty.
ReadonlypathRelative path of the file the failed action targeted, or '' for engine-level errors.
ReadonlysizeSize in bytes; always 0 for error events.
ReadonlytypeDiscriminant tag (always the literal string 'error').
errorevent — an action threw or the engine encountered a fatal condition. Always carries a non-emptymessagedescribing the failure so consumers don't need amessage ?? 'unknown'fallback.