def expand_query_safely(parsed, new_keywords: list[str],
                        max_keywords: int = 15):
    try:
        expanded = parsed.model_copy(deep=True)
    except AttributeError:
        import copy as _copy
        expanded = _copy.deepcopy(parsed)

    originals = list(expanded.retrieval.anchor_keywords or [])
    additions = [k for k in new_keywords if k not in originals]
    combined = originals + additions
    if len(combined) > max_keywords:
        kept_originals = originals[:max_keywords]
        room = max_keywords - len(kept_originals)
        combined = kept_originals + additions[-room:] if room > 0 else kept_originals
    expanded.retrieval.anchor_keywords = combined
    return expanded