Skills apollo-federation

install

source · Clone the upstream repo

git clone https://github.com/apollographql/skills

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/apollographql/skills "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/apollo-federation" ~/.claude/skills/apollographql-skills-apollo-federation && rm -rf "$T"

manifest: skills/apollo-federation/SKILL.md

source content

Apollo Federation Schema Authoring

Apollo Federation enables composing multiple GraphQL APIs (subgraphs) into a unified supergraph.

Federation 2 Schema Setup

Every Federation 2 subgraph must opt-in via

@link

extend schema
  @link(url: "https://specs.apollo.dev/federation/v2.12",
        import: ["@key", "@shareable", "@external", "@requires", "@provides"])

Import only the directives your subgraph uses.

Core Directives Quick Reference

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
```
@link
```
directive
ALWAYS import only the directives your subgraph uses
NEVER use
```
@shareable
```
without ensuring all subgraphs return identical values for that field
PREFER
```
@key
```
with single ID field for simple entity identification
USE
```
rover supergraph compose
```
to validate composition locally
USE
```
rover subgraph check
```
to validate against production supergraph