Use a definition

Author: benjie

spec/Section 4 -- Introspection.md

@@ -525,16 +525,15 @@ Fields\:
 
 ### The \_\_Capability Type
 
-The `__Service.capabilities` field exposes a list of capabilities that describe
-features supported by the GraphQL service but not directly expressible in the
-type system. These may include experimental GraphQL features (such as fragment
-arguments, operation descriptions, custom error behaviors), protocol support
-(such as subscriptions over WebSocket), or additional operational metadata (such
-as release identifiers).
-
-Capabilities may be supplied by the GraphQL implementation, by the service, or
-both. An individual entry in the capabilities list will have a capability
-identifier and may optionally provide a string value.
+:: A _capability_ describes a feature supported by the GraphQL service but not
+directly expressible in the type system. This may include experimental GraphQL
+features (such as new syntax or behavior), protocol support (such as GraphQL
+over WebSockets), or additional operational metadata (such as release
+identifiers). Capabilities may be supplied by the GraphQL implementation, by the
+service, or both.
+
+The `__Service.capabilities` field exposes a _capability_ list. A _capability_
+comprises of a capability identifier and optionally a string value.
 
 **Capability identifier**
 

spec/Section 6 -- Execution.md

@@ -865,11 +865,13 @@ _request_. If omitted, the _default error behavior_ of the service applies.
 Valid values for _error behavior_ are {"PROPAGATE"}, {"NO_PROPAGATE"} and
 {"HALT"}.
 
+<!-- https://github.com/prettier/prettier/issues/17286 -->
+<!-- prettier-ignore -->
 :: The _default error behavior_ of a service is implementation-defined. For
 compatibility with existing clients, services should default to {"PROPAGATE"}
-which reflects prior behavior. For new services, {"NO_PROPAGATE"} is
-recommended. The default error behavior is indicated via the
-`defaultErrorBehavior` field of the `__Service` introspection type.
+which reflects prior behavior. <!-- For new services, {"NO_PROPAGATE"} is
+recommended. --> The default error behavior is indicated via the
+`org.graphql.defaultErrorBehavior` _capability_.
 
 Note: {"HALT"} is not recommended as the _default error behavior_ because it
 prevents generating partial responses which may still contain useful data.