How do I install the Apollo Federation skill?

Run npx skillmds@latest add apollographql/apollo-federation in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Apollo Federation safe to use?

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Which AI agents work with Apollo Federation?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Apollo Federation free to use?

Yes. Installing skills from SkillMD is free. This skill is licensed under MIT.

Who published Apollo Federation?

apollographql (@apollographql) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Apollo Federation by apollographql — Agent Skill

Name: Apollo Federation
Rating: 4.2 (5 reviews)
Author: apollographql

Apollo Federation

Guide for authoring Apollo Federation subgraph schemas. Use this skill when: (1) creating new subgraph schemas for a federated supergraph, (2) defining or modifying entities with @key, (3) sharing types/fields across subgraphs with @shareable, (4) working with federation directives (@external, @requires, @provides, @override, @inaccessible), (5) troubleshooting composition errors, (6) any task involving federation schema design patterns.

apollographql 257a4dc 4 files · 37.8 KB Updated Sep 9, 2026

File contents

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. The version shown (v2.12) is illustrative — check the Federation changelog for currently supported versions before copying it verbatim.

A subgraph's @link version is a floor, not the composition version — see Federation versions for the full explanation.

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

---name: apollo-federationdescription: Guide for authoring Apollo Federation subgraph schemas. Use this skill when: (1) creating new subgraph schemas for a federated supergraph, (2) defining or modifying entities with @key, (3) sharing types/fields across subgraphs with @shareable, (4) working with federation directives (@external, @requires, @provides, @override, @inaccessible), (5) troubleshooting composition errors, (6) any task involving federation schema design patterns.license: MIT--- # 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`: ```graphql extend schema @link(url: "https://specs.apollo.dev/federation/v2.12", import: ["@key", "@shareable", "@external", "@requires", "@provides"]) ``` Import only the directives your subgraph uses. The version shown (`v2.12`) is illustrative — check the [Federation changelog](https://www.apollographql.com/docs/graphos/schema-design/federated-schemas/reference/versions) for currently supported versions before copying it verbatim. > A subgraph's `@link` version is a floor, not the composition version — see > [Federation versions](references/composition.md#federation-versions-floor-vs-composition) > for the full explanation. ## 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](references/directives.md) - All federation directives with syntax, examples, and rules - [Schema Patterns](references/schema-patterns.md) - Multi-subgraph patterns and recipes - [Composition](references/composition.md) - Composition rules, error codes, and debugging ## Key Patterns ### Entity Definition ```graphql type Product @key(fields: "id") { id: ID! name: String! price: Int } ``` ### Entity Contributions Across Subgraphs ```graphql # 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 ```graphql type Product @key(fields: "id") { id: ID! size: Int @external weight: Int @external shippingEstimate: String @requires(fields: "size weight") } ``` ### Value Types with @shareable ```graphql type Money @shareable { amount: Int! currency: String! } ``` ### Entity Stub (Reference Without Contributing) ```graphql 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

Frequently asked questions