paramsobject可选
业务参数，契约按 endpoint 选择；请勿再次嵌套 params。
news_by_symbol: {"type":"object","properties":{"symbol":{"type":"string","description":"股票/标的代码；例如 NVDA。"},"days":{"default":7,"minimum":1,"maximum":90,"type":"integer","description":"查询最近多少天。"},"limit":{"default":10,"minimum":1,"maximum":50,"type":"integer","description":"返回条数。"},"sortBy":{"enum":["relevance","time"],"default":"relevance","type":"string","description":"排序方式：relevance=相关性优先，time=发布时间倒序。"},"relevanceMode":{"enum":["related","primary"],"default":"related","type":"string","description":"相关性范围：related=保留全部关联新闻并重排，primary=仅返回主体相关或直接提及的新闻。"}},"required":["symbol"]}
news_digest: {"type":"object","properties":{"symbol":{"type":"string","description":"股票/标的代码，不带交易所后缀；例如 000957.SZ 传 000957。"},"days":{"default":7,"minimum":1,"maximum":30,"type":"integer","description":"查询最近多少天。"},"limit":{"default":10,"minimum":1,"maximum":20,"type":"integer","description":"返回条数。"}},"required":[]}
news_get: {"type":"object","properties":{"id":{"type":"string","description":"新闻 ID，对应新闻列表返回的 id 字段。"},"include_content":{"default":true,"type":"boolean","description":"是否返回正文 content。"}},"required":["id"]}
news_latest: {"type":"object","properties":{"hours":{"default":24,"minimum":1,"maximum":168,"type":"integer","description":"查询最近多少小时的新闻。"},"symbol":{"type":"string","description":"股票/标的代码，不带交易所后缀；例如 000957.SZ 传 000957。"},"limit":{"default":10,"minimum":1,"maximum":50,"type":"integer","description":"返回条数。"}},"required":[]}
news_related: {"type":"object","properties":{"id":{"type":"string","description":"新闻 ID，对应新闻列表返回的 id 字段。"},"limit":{"default":10,"minimum":1,"maximum":50,"type":"integer","description":"返回条数。"}},"required":["id"]}
news_search: {"type":"object","properties":{"query":{"type":"string","description":"语义检索文本；适合自然语言意图查询，会转换为 embedding 后按语义相似度搜索。"},"from":{"type":"string","description":"开始日期，格式 YYYY-MM-DD；默认最近 30 天。"},"to":{"type":"string","description":"结束日期，格式 YYYY-MM-DD；默认今天。"},"symbol":{"type":"string","description":"股票/标的代码，不带交易所后缀；例如 000957.SZ 传 000957。"},"limit":{"default":10,"minimum":1,"maximum":50,"type":"integer","description":"返回条数。"}},"required":["query"]}
