mcp/tools/trial_goods_tax.py

import math


class TrialGoodsTaxTool:
    name = 'trial_goods_tax'
    route_path = '/mcp/tools/trialGoodsTax'

    def __init__(self, api_client=None):
        self.api_client = api_client

    def metadata(self):
        number = {'type': 'number', 'exclusiveMinimum': 0, 'maximum': 1000000000}
        country = {
            'type': 'string',
            'minLength': 2,
            'maxLength': 3,
            'pattern': '^[A-Za-z]{2,3}$',
            'description': '国家代码，例如 CN、US。不得传中文国名或“国家名-代码”。',
        }
        return {
            'name': self.name,
            'description': (
                '使用场景：用户明确要对某一条已审核商品做关税试算时使用。'
                '必须同时提供 SKU、起运国国家代码、目的国国家代码、采购单价、SKU数量、总毛重和箱数。'
                '起运国和目的国只能填国家代码，例如 CN、US。'
                '同一 SKU 有多条时，号码类型不明确时必须先询问用户，国家不明确也必须先询问，确认前不得调用。'
                '不得根据号码格式猜测，不得跨字段或跨工具试查。'
                '返回预计关税金额，不保存试算结果。'
                '禁止使用：不查询商品列表，不修改商品或清关资料，不创建订单，不导出文件。'
                '查商品资料用 query_goods_info。'
            ),
            'input_schema': {
                'type': 'object',
                'properties': {
                    'sku': {
                        'type': 'string',
                        'minLength': 1,
                        'maxLength': 100,
                        'description': 'SKU。仅当用户明确说明是 SKU 时使用。',
                    },
                    'departure_country': dict(country, description='起运国。'),
                    'destination_country': dict(country, description='目的国。'),
                    'price': dict(number, description='采购单价，必须大于 0。'),
                    'qty': dict(number, description='SKU数量，必须大于 0。'),
                    'gross_weight': dict(number, description='总毛重，必须大于 0。'),
                    'box': dict(number, description='箱数，必须大于 0。'),
                },
                'required': [
                    'sku', 'departure_country', 'destination_country',
                    'price', 'qty', 'gross_weight', 'box',
                ],
                'additionalProperties': False,
            },
        }

    def call(
        self,
        sku='',
        departure_country='',
        destination_country='',
        price=None,
        qty=None,
        gross_weight=None,
        box=None,
        request_id='rq_trial_goods_tax',
        **_ignored,
    ):
        if self.api_client is None:
            raise RuntimeError('api client is required for trial_goods_tax')
        payload = {
            'sku': self._text(sku, 'sku', 100),
            'departure_country': self._country(departure_country, 'departure_country'),
            'destination_country': self._country(destination_country, 'destination_country'),
            'price': self._positive(price, 'price'),
            'qty': self._positive(qty, 'qty'),
            'gross_weight': self._positive(gross_weight, 'gross_weight'),
            'box': self._positive(box, 'box'),
        }
        if not payload['sku'] or not payload['departure_country'] or not payload['destination_country']:
            raise ValueError('sku, departure_country and destination_country are required')
        return self.api_client.call_tool(
            self.name, self.route_path, payload, request_id
        )

    @staticmethod
    def _country(value, field):
        if not isinstance(value, str):
            raise ValueError(field + ' must be a country code')
        value = value.strip().upper()
        if (
            len(value) < 2 or len(value) > 3
            or not value.isascii() or not value.isalpha()
        ):
            raise ValueError(field + ' must be a country code')
        return value

    @staticmethod
    def _text(value, field, max_length):
        if not isinstance(value, str):
            raise ValueError(field + ' must be a string')
        value = value.strip()
        if not value or len(value) > max_length:
            raise ValueError(field + ' is invalid')
        return value

    @staticmethod
    def _positive(value, field):
        if isinstance(value, bool) or not isinstance(value, (int, float)):
            raise ValueError(field + ' is invalid')
        if not math.isfinite(value) or value <= 0 or value > 1000000000:
            raise ValueError(field + ' is invalid')
        return value