Rails GraphQL Patterns

Analyze and recommend patterns for building GraphQL APIs in Rails with graphql-ruby.

Follow standard graphql-ruby conventions for type definitions, input types, enum types, query types, and basic mutations. This skill focuses on non-obvious patterns and opinionated decisions.

Core Principles

1. Batch loading: Always use DataLoader to prevent N+1 queries — never resolve associations directly
2. Structured errors: Return error arrays in mutation payloads, not exceptions
3. Field-level authorization: Check permissions per field, not just per query
4. Complexity limits: Set max_complexity and max_depth on the schema
5. Null annotations: Be intentional with null: true/false on every field

DataLoader for N+1 Prevention

Every association field MUST use DataLoader. Never call object.association directly in a resolver.