SKILL.md
$27
Directive
Purpose
Example
@key
Define entity with unique key
type Product @key(fields: "id")
@shareable
Allow multiple subgraphs to resolve field
type Position @shareable { x: Int! }
@external
Reference field from another subgraph
weight: Int @external
@requires
Computed field depending on external fields
shippingCost: Int @requires(fields: "weight")
@provides
Conditionally resolve external field
@provides(fields: "name")
@override
Migrate field to this subgraph
@override(from: "Products")
@inaccessible
Hide from API schema
internalId: ID! @inaccessible
@interfaceObject
Add fields to entity interface
type Media @interfaceObject
Reference Files
Detailed documentation for specific topics:
- Directives - All federation directives with syntax, examples, and rules
- Schema Patterns - Multi-subgraph patterns and recipes
- Composition - Composition rules, error codes, and debugging
Key Patterns
Entity Definition
type Product @key(fields: "id") {
id: ID!
name: String!
price: Int
}Entity Contributions Across Subgraphs
# Products subgraph
type Product @key(fields: "id") {
id: ID!
name: String!
price: Int
}
# Reviews subgraph
type Product @key(fields: "id") {
id: ID!
reviews: [Review!]!
averageRating: Float
}Computed Fields with @requires
type Product @key(fields: "id") {
id: ID!
size: Int @external
weight: Int @external
shippingEstimate: String @requires(fields: "size weight")
}Value Types with @shareable
type Money @shareable {
amount: Int!
currency: String!
}Entity Stub (Reference Without Contributing)
type Product @key(fields: "id", resolvable: false) {
id: ID!
}Ground Rules
- ALWAYS use Federation 2.x syntax with
@linkdirective
- ALWAYS import only the directives your subgraph uses
- NEVER use
@shareablewithout ensuring all subgraphs return identical values for that field
- PREFER
@keywith single ID field for simple entity identification
- USE
rover supergraph composeto validate composition locally
- USE
rover subgraph checkto validate against production supergraph