graphql-schema-generator skill

---
name: graphql-schema-generator
description: Generate GraphQL schema definition files (SDL) with types, queries, mutations, subscriptions, and resolvers for API development. Triggers on "create GraphQL schema", "generate GraphQL types", "GraphQL API for", "SDL schema".
---

# GraphQL Schema Generator

Generate complete GraphQL Schema Definition Language (SDL) files with types, queries, mutations, and subscriptions.

## Output Requirements

**File Output:** `schema.graphql` or `schema.gql`
**Format:** GraphQL SDL (Schema Definition Language)
**Standards:** GraphQL June 2018 or later spec

## When Invoked

Immediately generate a complete, valid GraphQL schema. Include appropriate types, queries, mutations, and input types for the domain.

## SDL Structure

```graphql
# Type definitions
type TypeName {
  field: Type
}

# Input types for mutations
input InputTypeName {
  field: Type
}

# Queries (read operations)
type Query {
  resource: Type
}

# Mutations (write operations)
type Mutation {
  createResource(input: InputType): Type
}

# Subscriptions (real-time)
type Subscription {
  resourceUpdated: Type
}
```

## Complete Templates

### Blog/CMS Schema
```graphql
# ===========================================
# Scalar Types
# ===========================================

scalar DateTime
scalar UUID

# ===========================================
# Enums
# ===========================================

enum PostStatus {
  DRAFT
  PUBLISHED
  ARCHIVED
}

enum SortOrder {
  ASC
  DESC
}

enum UserRole {
  ADMIN
  EDITOR
  AUTHOR
  READER
}

# ===========================================
# Interfaces
# ===========================================

interface Node {
  id: ID!
}

interface Timestamped {
  createdAt: DateTime!
  updatedAt: DateTime!
}

# ===========================================
# Types
# ===========================================

type User implements Node & Timestamped {
  id: ID!
  email: String!
  username: String!
  displayName: String
  avatar: String
  bio: String
  role: UserRole!
  posts(first: Int, after: String, status: PostStatus): PostConnection!
  comments(first: Int, after: String): CommentConnection!
  createdAt: DateTime!
  updatedAt: DateTime!
}

type Post implements Node & Timestamped {
  id: ID!
  title: String!
  slug: String!
  content: String!
  excerpt: String
  featuredImage: String
  status: PostStatus!
  author: User!
  categories: [Category!]!
  tags: [Tag!]!
  comments(first: Int, after: String): CommentConnection!
  commentCount: Int!
  viewCount: Int!
  publishedAt: DateTime
  createdAt: DateTime!
  updatedAt: DateTime!
}

type Comment implements Node & Timestamped {
  id: ID!
  content: String!
  author: User!
  post: Post!
  parent: Comment
  replies(first: Int, after: String): CommentConnection!
  createdAt: DateTime!
  updatedAt: DateTime!
}

type Category implements Node {
  id: ID!
  name: String!
  slug: String!
  description: String
  parent: Category
  children: [Category!]!
  posts(first: Int, after: String): PostConnection!
  postCount: Int!
}

type Tag implements Node {
  id: ID!
  name: String!
  slug: String!
  posts(first: Int, after: String): PostConnection!
  postCount: Int!
}

# ===========================================
# Connection Types (Relay-style Pagination)
# ===========================================

type PageInfo {
  hasNextPage: Boolean!
  hasPreviousPage: Boolean!
  startCursor: String
  endCursor: String
}

type PostConnection {
  edges: [PostEdge!]!
  pageInfo: PageInfo!
  totalCount: Int!
}

type PostEdge {
  node: Post!
  cursor: String!
}

type CommentConnection {
  edges: [CommentEdge!]!
  pageInfo: PageInfo!
  totalCount: Int!
}

type CommentEdge {
  node: Comment!
  cursor: String!
}

type UserConnection {
  edges: [UserEdge!]!
  pageInfo: PageInfo!
  totalCount: Int!
}

type UserEdge {
  node: User!
  cursor: String!
}

# ===========================================
# Input Types
# ===========================================

input CreatePostInput {
  title: String!
  content: String!
  excerpt: String
  featuredImage: String
  status: PostStatus = DRAFT
  categoryIds: [ID!]
  tagNames: [String!]
}

input UpdatePostInput {
  title: String
  content: String
  excerpt: String
  featuredImage: String
  status: PostStatus
  categoryIds: [ID!]
  tagNames: [String!]
}

input CreateCommentInput {
  postId: ID!
  parentId: ID
  content: String!
}

input UpdateCommentInput {
  content: String!
}

input CreateCategoryInput {
  name: String!
  description: String
  parentId: ID
}

input PostFilterInput {
  status: PostStatus
  authorId: ID
  categoryId: ID
  tagId: ID
  search: String
}

input PostOrderInput {
  field: PostOrderField!
  direction: SortOrder!
}

enum PostOrderField {
  CREATED_AT
  UPDATED_AT
  PUBLISHED_AT
  TITLE
  VIEW_COUNT
}

# ===========================================
# Queries
# ===========================================

type Query {
  # User queries
  me: User
  user(id: ID!): User
  userByUsername(username: String!): User
  users(
    first: Int
    after: String
    role: UserRole
  ): UserConnection!

  # Post queries
  post(id: ID!): Post
  postBySlug(slug: String!): Post
  posts(
    first: Int
    after: String
    filter: PostFilterInput
    orderBy: PostOrderInput
  ): PostConnection!

  # Search
  searchPosts(query: String!, first: Int, after: String): PostConnection!

  # Category queries
  category(id: ID!): Category
  categoryBySlug(slug: String!): Category
  categories(parentId: ID): [Category!]!

  # Tag queries
  tag(id: ID!): Tag
  tagBySlug(slug: String!): Tag
  tags(first: Int): [Tag!]!
  popularTags(limit: Int = 10): [Tag!]!

  # Comment queries
  comment(id: ID!): Comment
}

# ===========================================
# Mutations
# ===========================================

type Mutation {
  # Auth mutations
  login(email: String!, password: String!): AuthPayload!
  register(email: String!, username: String!, password: String!): AuthPayload!
  logout: Boolean!
  refreshToken(refreshToken: String!): AuthPayload!

  # User mutations
  updateProfile(
    displayName: String
    bio: String
    avatar: String
  ): User!
  changePassword(currentPassword: String!, newPassword: String!): Boolean!

  # Post mutations
  createPost(input: CreatePostInput!): Post!
  updatePost(id: ID!, input: UpdatePostInput!): Post!
  deletePost(id: ID!): Boolean!
  publishPost(id: ID!): Post!
  unpublishPost(id: ID!): Post!

  # Comment mutations
  createComment(input: CreateCommentInput!): Comment!
  updateComment(id: ID!, input: UpdateCommentInput!): Comment!
  deleteComment(id: ID!): Boolean!

  # Category mutations (admin only)
  createCategory(input: CreateCategoryInput!): Category!
  updateCategory(id: ID!, name: String, description: String): Category!
  deleteCategory(id: ID!): Boolean!

  # Tag mutations
  createTag(name: String!): Tag!
  deleteTag(id: ID!): Boolean!
}

# ===========================================
# Subscriptions
# ===========================================

type Subscription {
  postPublished: Post!
  commentAdded(postId: ID!): Comment!
  postUpdated(id: ID!): Post!
}

# ===========================================
# Payload Types
# ===========================================

type AuthPayload {
  accessToken: String!
  refreshToken: String!
  expiresIn: Int!
  user: User!
}

# ===========================================
# Directives
# ===========================================

directive @auth(requires: UserRole = READER) on FIELD_DEFINITION
directive @deprecated(reason: String) on FIELD_DEFINITION
```

### E-commerce Schema
```graphql
scalar DateTime
scalar Decimal
scalar JSON

enum OrderStatus {
  PENDING
  CONFIRMED
  PROCESSING
  SHIPPED
  DELIVERED
  CANCELLED
  REFUNDED
}

enum PaymentStatus {
  PENDING
  COMPLETED
  FAILED
  REFUNDED
}

type Product implements Node {
  id: ID!
  sku: String!
  name: String!
  slug: String!
  description: String
  price: Decimal!
  compareAtPrice: Decimal
  images: [ProductImage!]!
  category: Category
  variants: [ProductVariant!]!
  inventory: Int!
  isAvailable: Boolean!
  attributes: JSON
  createdAt: DateTime!
  updatedAt: DateTime!
}

type ProductVariant {
  id: ID!
  name: String!
  sku: String!
  price: Decimal!
  inventory: Int!
  attributes: JSON
}

type ProductImage {
  id: ID!
  url: String!
  altText: String
  isPrimary: Boolean!
}

type Cart {
  id: ID!
  items: [CartItem!]!
  subtotal: Decimal!
  tax: Decimal!
  shipping: Decimal!
  total: Decimal!
  itemCount: Int!
}

type CartItem {
  id: ID!
  product: Product!
  variant: ProductVariant
  quantity: Int!
  unitPrice: Decimal!
  total: Decimal!
}

type Order implements Node {
  id: ID!
  orderNumber: String!
  customer: Customer!
  items: [OrderItem!]!
  status: OrderStatus!
  paymentStatus: PaymentStatus!
  subtotal: Decimal!
  tax: Decimal!
  shipping: Decimal!
  discount: Decimal!
  total: Decimal!
  shippingAddress: Address!
  billingAddress: Address!
  notes: String
  createdAt: DateTime!
  updatedAt: DateTime!
}

input AddToCartInput {
  productId: ID!
  variantId: ID
  quantity: Int!
}

input CheckoutInput {
  shippingAddressId: ID!
  billingAddressId: ID
  paymentMethodId: ID!
  notes: String
}

type Query {
  # Products
  product(id: ID, slug: String): Product
  products(
    first: Int
    after: String
    categoryId: ID
    search: String
    minPrice: Decimal
    maxPrice: Decimal
  ): ProductConnection!

  # Cart
  cart: Cart

  # Orders
  order(id: ID!): Order
  orders(first: Int, after: String, status: OrderStatus): OrderConnection!
}

type Mutation {
  # Cart
  addToCart(input: AddToCartInput!): Cart!
  updateCartItem(itemId: ID!, quantity: Int!): Cart!
  removeFromCart(itemId: ID!): Cart!
  clearCart: Cart!

  # Checkout
  checkout(input: CheckoutInput!): Order!

  # Orders
  cancelOrder(id: ID!, reason: String): Order!
}

type Subscription {
  orderStatusChanged(orderId: ID!): Order!
}
```

## Best Practices

### Naming Conventions
- Types: PascalCase (`User`, `BlogPost`)
- Fields: camelCase (`firstName`, `createdAt`)
- Enums: SCREAMING_SNAKE_CASE (`PENDING`, `IN_PROGRESS`)
- Inputs: PascalCase with Input suffix (`CreateUserInput`)

### Nullable vs Non-Null
```graphql
# Non-null (required)
field: String!

# Nullable (optional)
field: String

# Non-null list of non-null items
field: [String!]!

# Nullable list of nullable items
field: [String]
```

## Validation Checklist

Before outputting, verify:
- [ ] All types referenced exist
- [ ] Query type has at least one field
- [ ] Input types use only scalar, enum, or other input types
- [ ] No circular references in non-null fields
- [ ] Pagination follows Relay spec (if used)
- [ ] Naming conventions are consistent
- [ ] Descriptions added for complex fields

## Example Invocations

**Prompt:** "Create GraphQL schema for a task management app"
**Output:** Complete `schema.graphql` with tasks, projects, users, assignments.

**Prompt:** "Generate GraphQL types for social media API"
**Output:** Complete `schema.graphql` with users, posts, followers, likes, comments.

**Prompt:** "GraphQL schema for inventory management system"
**Output:** Complete `schema.graphql` with products, warehouses, stock, transfers.