A short, human-readable summary of the problem that SHOULD NOT change from occurrence to occurrence of the problem, except for purposes of localization.

If an error can be associated to a particular point in the requested GraphQL document, it should contain a list of locations.

If an error can be associated to a particular field in the GraphQL result, it must contain an entry with the key path that details the path of the response field which experienced the error. This allows clients to identify whether a null result is intentional or caused by a runtime error.

Reserved for implementors to extend the protocol however they see fit, and hence there are no additional restrictions on its contents.