graphql

GraphQL Core Knowledge

Deep Knowledge: Use mcp__documentation__fetch_docs with technology: graphql for comprehensive documentation.

Schema Definition

type User {
  id: ID!
  name: String!
  email: String!
  posts: [Post!]!
  createdAt: DateTime!
}

type Post {
  id: ID!
  title: String!
  content: String
  author: User!
  published: Boolean!
}

type Query {
  user(id: ID!): User
  users(limit: Int, offset: Int): [User!]!
  post(id: ID!): Post
}

type Mutation {
  createUser(input: CreateUserInput!): User!
  updateUser(id: ID!, input: UpdateUserInput!): User!
  deleteUser(id: ID!): Boolean!
}

input CreateUserInput {
  name: String!
  email: String!
}

Resolvers

const resolvers = {
  Query: {
    user: (_, { id }, context) => {
      return context.db.users.findUnique({ where: { id } });
    },
    users: (_, { limit, offset }, context) => {
      return context.db.users.findMany({ take: limit, skip: offset });
    },
  },
  Mutation: {
    createUser: (_, { input }, context) => {
      return context.db.users.create({ data: input });
    },
  },
  User: {
    posts: (parent, _, context) => {
      return context.db.posts.findMany({ where: { authorId: parent.id } });
    },
  },
};

Queries

query GetUser($id: ID!) {
  user(id: $id) {
    id
    name
    email
    posts {
      title
      published
    }
  }
}

mutation CreateUser($input: CreateUserInput!) {
  createUser(input: $input) {
    id
    name
  }
}

When NOT to Use This Skill

• REST API design (use rest-api skill)
• OpenAPI/Swagger documentation (use openapi skill)
• tRPC type-safe APIs (use trpc skill)
• Generating GraphQL types from schema (use graphql-codegen skill)
• Simple CRUD operations where REST is sufficient

Best Practices

Do	Don't
Use input types for mutations	N+1 queries (use DataLoader)
Implement pagination	Return unbounded lists
Add field-level auth	Expose sensitive data
Use fragments for reuse	Over-fetch data