How do I install the Apollo Federation skill?

Run npx skillmds add om-scogo/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?

This skill has not completed SkillMD's automated safety review yet. Capability flags: makes network calls. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

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?

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

Apollo Federation by om-scogo — Agent Skill

Name: Apollo Federation
Rating: 4.2 (5 reviews)
Author: om-scogo

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.

om-scogo 4c58225 4 files · 10.9 KB Updated Sep 9, 2026 0 repo stars

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.

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. ## 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