diff --git a/src/negative_test/drupal-services/drupal-services-autoconfigure.yml b/src/negative_test/drupal-services/drupal-services-autoconfigure.yml
new file mode 100644
index 00000000000..294d5a9ac0f
--- /dev/null
+++ b/src/negative_test/drupal-services/drupal-services-autoconfigure.yml
@@ -0,0 +1,9 @@
+# yaml-language-server: $schema=../../schemas/json/drupal-services.json
+services:
+  #Defines a service with autoconfiguration but uses string.
+  Drupal\Test\Negative\WithAutoconfigure\String:
+    autoconfigure: 'ok'
+
+  #Defines a service with autoconfiguration but uses integer.
+  Drupal\Test\Negative\WithAutoconfigure\Integer:
+    autoconfigure: 1
diff --git a/src/negative_test/drupal-services/drupal-services-autowire.yml b/src/negative_test/drupal-services/drupal-services-autowire.yml
new file mode 100644
index 00000000000..a0415c98648
--- /dev/null
+++ b/src/negative_test/drupal-services/drupal-services-autowire.yml
@@ -0,0 +1,11 @@
+# yaml-language-server: $schema=../../schemas/json/drupal-services.json
+services:
+  # Defines a service with autowiring but string instead of boolean.
+  test.negative.with.autowiring.string:
+    class: Drupal\Example\WithAutowiring
+    autowire: 'yes'
+
+  # Defines a service with autowiring but string instead of boolean.
+  test.negative.with.autowiring.integer:
+    class: Drupal\Example\WithAutowiring
+    autowire: 1
diff --git a/src/negative_test/drupal-services/drupal-services-decoration.yml b/src/negative_test/drupal-services/drupal-services-decoration.yml
new file mode 100644
index 00000000000..d9d284db0dd
--- /dev/null
+++ b/src/negative_test/drupal-services/drupal-services-decoration.yml
@@ -0,0 +1,39 @@
+# yaml-language-server: $schema=../../schemas/json/drupal-services.json
+services:
+  # Wrong type: decoration_priority must be an integer, not a string.
+  test.negative.decoration_priority_string:
+    class: Drupal\test\Invalid
+    decorates: test.decorated_service
+    decoration_priority: 'high'
+    arguments: []
+
+  # Invalid enum value: not one of exception/ignore/null.
+  test.negative.decoration_on_invalid_bad_value:
+    class: Drupal\test\Invalid
+    decorates: test.does_not_exist
+    decoration_on_invalid: maybe
+    arguments: []
+
+  # The exact pitfall from the null-quoting issue: an unquoted null
+  # becomes YAML's null type, not the schema's string enum member.
+  test.negative.decoration_on_invalid_unquoted_null:
+    class: Drupal\test\Invalid
+    decorates: test.does_not_exist
+    decoration_on_invalid: null
+    arguments: []
+
+  # Wrong type: decoration_inner_name must be a string, not a service
+  # reference array or object.
+  test.negative.decoration_inner_name_wrong_type:
+    class: Drupal\test\Invalid
+    decorates: test.decorated_service
+    decoration_inner_name: ['not', 'a', 'string']
+    arguments: []
+
+  # Typo/misspelled key: additionalProperties is false on the service
+  # object, so this should be rejected outright.
+  test.negative.decoration_typo:
+    class: Drupal\test\Invalid
+    decorates: test.decorated_service
+    decoration_priorty: 5
+    arguments: []
diff --git a/src/schemas/json/drupal-services.json b/src/schemas/json/drupal-services.json
index 5d7925f4a2f..f9ccde4bc9e 100644
--- a/src/schemas/json/drupal-services.json
+++ b/src/schemas/json/drupal-services.json
@@ -44,6 +44,19 @@
                 "title": "Service name to decorate",
                 "type": "string"
               },
+              "decoration_priority": {
+                "title": "Priority of this decorator relative to others decorating the same service",
+                "type": "integer"
+              },
+              "decoration_inner_name": {
+                "title": "Overrides the default '<id>.inner' name for the decorated inner service",
+                "type": "string"
+              },
+              "decoration_on_invalid": {
+                "title": "Behavior when the decorated service does not exist",
+                "type": "string",
+                "enum": ["exception", "ignore", "null"]
+              },
               "deprecated": {
                 "title": "A flag indicating that the service is deprecated",
                 "type": "string"
@@ -80,6 +93,14 @@
                   "type": "string"
                 }
               },
+              "autowire": {
+                "title": "Service dependencies can be autowired",
+                "type": "boolean"
+              },
+              "autoconfigure": {
+                "title": "Service handler can be automatically configured",
+                "type": "boolean"
+              },
               "tags": {
                 "title": "List of tags tell Drupal that your service can be processed in some special way",
                 "examples": [
diff --git a/src/test/drupal-services/drupal-services.yml b/src/test/drupal-services/drupal-services.yml
index f0eba38dcb1..512baae5f15 100644
--- a/src/test/drupal-services/drupal-services.yml
+++ b/src/test/drupal-services/drupal-services.yml
@@ -12,5 +12,65 @@ services:
   # Defines an alias shortcut.
   Drupal\Example\WithModuleHandler: '@example.with_module_handler'
 
+  # Defines a service with autowiring.
+  example.with.autowiring:
+    class: Drupal\Example\WithAutowiring
+    autowire: true
+
+  #Defines a service with autoconfiguration.
+  Drupal\Example\WithAutoconfigure:
+    autoconfigure: true
+
+  # decoration_priority: controls stacking order when multiple decorators
+  # target the same service. Accepts any integer, including negative.
+  test.decorator.high_priority:
+    class: Drupal\test\HighPriorityDecorator
+    decorates: test.decorated_service
+    decoration_priority: 10
+    arguments: ['@test.decorator.high_priority.inner']
+
+  test.decorator.negative_priority:
+    class: Drupal\test\NegativePriorityDecorator
+    decorates: test.decorated_service
+    decoration_priority: -5
+    arguments: ['@test.decorator.negative_priority.inner']
+
+  # decoration_inner_name: overrides the default '<id>.inner' name used
+  # to reference the decorated service.
+  test.decorator.custom_inner_name:
+    class: Drupal\test\CustomInnerNameDecorator
+    decorates: test.decorated_service
+    decoration_inner_name: test.decorator.custom_inner_name.original
+    arguments: ['@test.decorator.custom_inner_name.original']
+
+  # decoration_on_invalid: each of the three valid Symfony behaviors.
+  test.decorator.on_invalid_exception:
+    class: Drupal\test\OnInvalidExceptionDecorator
+    decorates: test.does_not_exist
+    decoration_on_invalid: exception
+    arguments: ['@test.decorator.on_invalid_exception.inner']
+
+  test.decorator.on_invalid_ignore:
+    class: Drupal\test\OnInvalidIgnoreDecorator
+    decorates: test.does_not_exist
+    decoration_on_invalid: ignore
+    arguments: ['@test.decorator.on_invalid_ignore.inner']
+
+  test.decorator.on_invalid_null:
+    class: Drupal\test\OnInvalidNullDecorator
+    decorates: test.does_not_exist
+    decoration_on_invalid: 'null'
+    arguments: ['@test.decorator.on_invalid_null.inner']
+
+  # Combined case: all four decoration options used together, as they
+  # might realistically appear in a single service definition.
+  test.decorator.full_combination:
+    class: Drupal\test\FullDecorator
+    decorates: test.decorated_service
+    decoration_priority: 5
+    decoration_inner_name: test.decorator.full_combination.original
+    decoration_on_invalid: ignore
+    arguments: ['@test.decorator.full_combination.original']
+
 parameters:
   example.parameter: TRUE