Directive Introspection Behavior Across GraphQL Spec Versions

Directive Introspection Behavior Across GraphQL Spec Versions

Goal: Determine whether a GraphQL server should expose directive definitions through the introspection system and how this exposure should be handled for both built‑in and custom directives.

Constraints: The GraphQL specification did not standardize directive introspection until the 2018‑06 release, leaving earlier implementations to decide independently whether to include a __schema.directives field. This creates uncertainty about expected behavior, potential schema size increase, and security implications when introspection is enabled in production.

Questions:

• What is the mandated behavior for directive introspection in spec versions prior to 2018‑06?
• How should servers represent custom directives in __schema.directives when introspection is enabled?
• Are there recommended limits on the depth or size of directive introspection responses to avoid memory pressure or timeout issues?