@dataclass
class AutoMergeGuard:
    """
    Name-only high-confidence matches route to review instead of auto-merge.
    At least one structural attribute must agree before auto-merge triggers.
    """
    structural_keys = [
        "registration_number_prefix",  # first 6 chars of company reg number
        "jurisdiction_code",            # ISO country + subdivision
        "address_locality",             # city-level normalized
    ]

    def check(self, candidate_pair: dict) -> bool:
        name_sim = candidate_pair.get("name_similarity", 0)
        if name_sim < 0.95:
            return True  # not name-only

        structural_agreement = any(
            candidate_pair.get(f"{key}_match", False)
            for key in self.structural_keys
        )
        return structural_agreement