extend schema @link(url: "https://specs.apollo.dev/federation/v2.3") type Author @federation__key(fields: "name") { id: ID! @federation__shareable name: String! articles: [Article] } type Article { id: ID! title: String! content: String author: Author } type Query { authors: [Author] articles: [Article] authorById(id: ID!): Author articleById(id: ID!): Article } type Mutation { addAuthor(name: String!, age: Int): Author addArticle(title: String!, content: String, authorId: ID!): Article }