apollo-connectors

This skill is a structured authoring guide for integrating REST APIs into GraphQL supergraphs using Apollo Connectors and the @source and @connect directives. It addresses the difficulty of correctly mapping REST responses into a federated GraphQL schema by giving an AI assistant a disciplined process and a set of reference files covering the connector grammar, transformation methods, mapping variables, entity patterns, and validation commands.

The workflow enforces a five-step process: research the API and its responses, implement a schema from a provided template, validate by composing the supergraph with rover, execute the connector with rover to confirm behavior, and add tests run via rover connector test. It documents key rules for selection mapping (preferring sub-selections, avoiding an unnecessary root selector, correct field aliasing), entity modeling with @connect, and literal values. Reference files enumerate the exact string, array, logical, math, and type-coercion methods available and explicitly instruct the assistant not to invent method names, plus a troubleshooting guide covering common errors like missing entity connectors, incorrect federation and connect versions, and invalid bodies. If GraphOS MCP tools are available it uses connectors-spec and documentation search tools to ground its work.

It targets GraphQL platform engineers and backend developers building or maintaining Apollo Federation supergraphs who want to wrap existing REST endpoints without writing custom resolver code. The skill only shells out to the read-and-compose oriented rover CLI, making it a documentation-and-scaffolding aid rather than a tool that performs risky operations.