diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index 463488b6..4ad3fef3 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "0.17.1"
+  ".": "0.18.0"
 }
\ No newline at end of file
diff --git a/.stats.yml b/.stats.yml
index 65629665..bbf5750e 100644
--- a/.stats.yml
+++ b/.stats.yml
@@ -1,4 +1,4 @@
 configured_endpoints: 109
-openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/openai%2Fopenai-6a1bfd4738fff02ef5becc3fdb2bf0cd6c026f2c924d4147a2a515474477dd9a.yml
+openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/openai%2Fopenai-9cadfad609f94f20ebf74fdc06a80302f1a324dc69700a309a8056aabca82fd2.yml
 openapi_spec_hash: 3eb8d86c06f0bb5e1190983e5acfc9ba
-config_hash: a67c5e195a59855fe8a5db0dc61a3e7f
+config_hash: 68337b532875626269c304372a669f67
diff --git a/CHANGELOG.md b/CHANGELOG.md
index a1823fa6..9e1360ee 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,22 @@
 # Changelog
 
+## 0.18.0 (2025-08-11)
+
+Full Changelog: [v0.17.1...v0.18.0](https://github.com/openai/openai-ruby/compare/v0.17.1...v0.18.0)
+
+### ⚠ BREAKING CHANGES
+
+* structured output desc should go on array items not array itself ([#799](https://github.com/openai/openai-ruby/issues/799))
+
+### Bug Fixes
+
+* structured output desc should go on array items not array itself ([#799](https://github.com/openai/openai-ruby/issues/799)) ([ff507d0](https://github.com/openai/openai-ruby/commit/ff507d095ff703ba3b44ab82b06eb4314688d4eb))
+
+
+### Chores
+
+* **internal:** update test skipping reason ([c815703](https://github.com/openai/openai-ruby/commit/c815703062ce79d2cb14f252ee5d23cf4ebf15ca))
+
 ## 0.17.1 (2025-08-09)
 
 Full Changelog: [v0.17.0...v0.17.1](https://github.com/openai/openai-ruby/compare/v0.17.0...v0.17.1)
diff --git a/Gemfile.lock b/Gemfile.lock
index cbdbfc91..2a86b134 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -11,7 +11,7 @@ GIT
 PATH
   remote: .
   specs:
-    openai (0.17.1)
+    openai (0.18.0)
       connection_pool
 
 GEM
diff --git a/README.md b/README.md
index bac257a3..631e0c9c 100644
--- a/README.md
+++ b/README.md
@@ -15,7 +15,7 @@ To use this gem, install via Bundler by adding the following to your application
 <!-- x-release-please-start-version -->
 
 ```ruby
-gem "openai", "~> 0.17.1"
+gem "openai", "~> 0.18.0"
 ```
 
 <!-- x-release-please-end -->
diff --git a/examples/structured_outputs_chat_completions.rb b/examples/structured_outputs_chat_completions.rb
index 11aa6728..707c741f 100755
--- a/examples/structured_outputs_chat_completions.rb
+++ b/examples/structured_outputs_chat_completions.rb
@@ -22,7 +22,7 @@ class CalendarEvent < OpenAI::BaseModel
   required :name, String
   required :date, String
   required :participants, OpenAI::ArrayOf[Participant]
-  required :optional_participants, OpenAI::ArrayOf[Participant], nil?: true
+  required :optional_participants, OpenAI::ArrayOf[Participant, doc: "who might not show up"], nil?: true
   required :is_virtual, OpenAI::Boolean
   required :location,
            OpenAI::UnionOf[String, Location],
diff --git a/examples/structured_outputs_responses.rb b/examples/structured_outputs_responses.rb
index 5a7be6ab..25aa4442 100755
--- a/examples/structured_outputs_responses.rb
+++ b/examples/structured_outputs_responses.rb
@@ -21,7 +21,7 @@ class CalendarEvent < OpenAI::BaseModel
   required :name, String
   required :date, String
   required :participants, OpenAI::ArrayOf[Participant]
-  required :optional_participants, OpenAI::ArrayOf[Participant], nil?: true
+  required :optional_participants, OpenAI::ArrayOf[Participant, doc: "who might not show up"], nil?: true
   required :is_virtual, OpenAI::Boolean
   required :location,
            OpenAI::UnionOf[String, Location],
diff --git a/lib/openai/helpers/structured_output/array_of.rb b/lib/openai/helpers/structured_output/array_of.rb
index cf134ea9..fb49cce1 100644
--- a/lib/openai/helpers/structured_output/array_of.rb
+++ b/lib/openai/helpers/structured_output/array_of.rb
@@ -30,19 +30,11 @@ def to_json_schema_inner(state:)
               state: state
             )
             items = OpenAI::Helpers::StructuredOutput::JsonSchemaConverter.to_nilable(items) if nilable?
+            OpenAI::Helpers::StructuredOutput::JsonSchemaConverter.assoc_meta!(items, meta: @meta)
 
-            schema = {type: "array", items: items}
-            description.nil? ? schema : schema.update(description: description)
+            {type: "array", items: items}
           end
         end
-
-        # @return [String, nil]
-        attr_reader :description
-
-        def initialize(type_info, spec = {})
-          super
-          @description = [type_info, spec].grep(Hash).filter_map { _1[:doc] }.first
-        end
       end
     end
   end
diff --git a/lib/openai/helpers/structured_output/base_model.rb b/lib/openai/helpers/structured_output/base_model.rb
index 5294df80..a6914c26 100644
--- a/lib/openai/helpers/structured_output/base_model.rb
+++ b/lib/openai/helpers/structured_output/base_model.rb
@@ -28,15 +28,13 @@ def to_json_schema_inner(state:)
             OpenAI::Helpers::StructuredOutput::JsonSchemaConverter.cache_def!(state, type: self) do
               path = state.fetch(:path)
               properties = fields.to_h do |name, field|
-                type, nilable = field.fetch_values(:type, :nilable)
+                type, nilable, meta = field.fetch_values(:type, :nilable, :meta)
                 new_state = {**state, path: [*path, ".#{name}"]}
 
                 schema =
                   case type
-                  in {"$ref": String}
-                    type
                   in OpenAI::Helpers::StructuredOutput::JsonSchemaConverter
-                    type.to_json_schema_inner(state: new_state).update(field.slice(:description))
+                    type.to_json_schema_inner(state: new_state)
                   else
                     OpenAI::Helpers::StructuredOutput::JsonSchemaConverter.to_json_schema_inner(
                       type,
@@ -44,6 +42,8 @@ def to_json_schema_inner(state:)
                     )
                   end
                 schema = OpenAI::Helpers::StructuredOutput::JsonSchemaConverter.to_nilable(schema) if nilable
+                OpenAI::Helpers::StructuredOutput::JsonSchemaConverter.assoc_meta!(schema, meta: meta)
+
                 [name, schema]
               end
 
@@ -58,13 +58,6 @@ def to_json_schema_inner(state:)
         end
 
         class << self
-          def required(name_sym, type_info, spec = {})
-            super
-
-            doc = [type_info, spec].grep(Hash).filter_map { _1[:doc] }.first
-            known_fields.fetch(name_sym).update(description: doc) unless doc.nil?
-          end
-
           def optional(...)
             # rubocop:disable Layout/LineLength
             message = "`optional` is not supported for structured output APIs, use `#required` with `nil?: true` instead"
diff --git a/lib/openai/helpers/structured_output/json_schema_converter.rb b/lib/openai/helpers/structured_output/json_schema_converter.rb
index 3a6c2ba9..35994f76 100644
--- a/lib/openai/helpers/structured_output/json_schema_converter.rb
+++ b/lib/openai/helpers/structured_output/json_schema_converter.rb
@@ -46,7 +46,7 @@ def to_nilable(schema)
             in {"$ref": String}
               {
                 anyOf: [
-                  schema.update(OpenAI::Helpers::StructuredOutput::JsonSchemaConverter::NO_REF => true),
+                  schema.merge!(OpenAI::Helpers::StructuredOutput::JsonSchemaConverter::NO_REF => true),
                   {type: null}
                 ]
               }
@@ -60,6 +60,17 @@ def to_nilable(schema)
             end
           end
 
+          # @api private
+          #
+          # @param schema [Hash{Symbol=>Object}]
+          def assoc_meta!(schema, meta:)
+            xformed = meta.transform_keys(doc: :description)
+            if schema.key?(:$ref) && !xformed.empty?
+              schema.merge!(OpenAI::Helpers::StructuredOutput::JsonSchemaConverter::NO_REF => true)
+            end
+            schema.merge!(xformed)
+          end
+
           # @api private
           #
           # @param state [Hash{Symbol=>Object}]
@@ -116,12 +127,17 @@ def to_json_schema(type)
 
               case refs
               in [ref]
-                ref.replace(sch)
+                ref.replace(ref.except(:$ref).merge(sch))
               in [_, ref, *]
                 reused_defs.store(ref.fetch(:$ref), sch)
+                refs.each do
+                  unless (meta = _1.except(:$ref)).empty?
+                    _1.replace(allOf: [_1.slice(:$ref), meta])
+                  end
+                end
               else
               end
-              no_refs.each { _1.replace(sch) }
+              no_refs.each { _1.replace(_1.except(:$ref).merge(sch)) }
             end
 
             xformed = reused_defs.transform_keys { _1.delete_prefix("#/$defs/") }
diff --git a/lib/openai/helpers/structured_output/union_of.rb b/lib/openai/helpers/structured_output/union_of.rb
index 5ae7086b..64dd3fff 100644
--- a/lib/openai/helpers/structured_output/union_of.rb
+++ b/lib/openai/helpers/structured_output/union_of.rb
@@ -56,16 +56,8 @@ def self.[](...) = new(...)
 
         # @param variants [Array<generic<Member>>]
         def initialize(*variants)
-          case variants
-          in [Symbol => d, Hash => vs]
-            discriminator(d)
-            vs.each do |k, v|
-              v.is_a?(Proc) ? variant(k, v) : variant(k, -> { v })
-            end
-          else
-            variants.each do |v|
-              v.is_a?(Proc) ? variant(v) : variant(-> { v })
-            end
+          variants.each do |v|
+            v.is_a?(Proc) ? variant(v) : variant(-> { v })
           end
         end
       end
diff --git a/lib/openai/version.rb b/lib/openai/version.rb
index 32d93453..a326627c 100644
--- a/lib/openai/version.rb
+++ b/lib/openai/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module OpenAI
-  VERSION = "0.17.1"
+  VERSION = "0.18.0"
 end
diff --git a/rbi/openai/helpers/structured_output/array_of.rbi b/rbi/openai/helpers/structured_output/array_of.rbi
index b0c70ce6..a9d9cf14 100644
--- a/rbi/openai/helpers/structured_output/array_of.rbi
+++ b/rbi/openai/helpers/structured_output/array_of.rbi
@@ -7,9 +7,6 @@ module OpenAI
         include OpenAI::Helpers::StructuredOutput::JsonSchemaConverter
 
         Elem = type_member(:out)
-
-        sig { returns(String) }
-        attr_reader :description
       end
     end
   end
diff --git a/rbi/openai/helpers/structured_output/json_schema_converter.rbi b/rbi/openai/helpers/structured_output/json_schema_converter.rbi
index f32e2d04..0174fade 100644
--- a/rbi/openai/helpers/structured_output/json_schema_converter.rbi
+++ b/rbi/openai/helpers/structured_output/json_schema_converter.rbi
@@ -46,6 +46,16 @@ module OpenAI
           def to_nilable(schema)
           end
 
+          # @api private
+          sig do
+            params(
+              schema: OpenAI::Helpers::StructuredOutput::JsonSchema,
+              meta: OpenAI::Internal::AnyHash
+            ).void
+          end
+          def assoc_meta!(schema, meta:)
+          end
+
           # @api private
           sig do
             params(
diff --git a/test/openai/helpers/structured_output_test.rb b/test/openai/helpers/structured_output_test.rb
index 01cf9b0c..0cacaf9f 100644
--- a/test/openai/helpers/structured_output_test.rb
+++ b/test/openai/helpers/structured_output_test.rb
@@ -22,9 +22,10 @@ def test_misuse
   E1 = OpenAI::Helpers::StructuredOutput::EnumOf[:one]
 
   class M1 < OpenAI::Helpers::StructuredOutput::BaseModel
-    required :a, String
+    required :a, String, doc: "dog"
     required :b, Integer, nil?: true
-    required :c, E1, nil?: true
+    required :c, E1, nil?: true, doc: "dog"
+    required :d, E1, doc: "dog"
   end
 
   class M2 < OpenAI::Helpers::StructuredOutput::BaseModel
@@ -36,7 +37,7 @@ class M3 < OpenAI::Helpers::StructuredOutput::BaseModel
   end
 
   U1 = OpenAI::Helpers::StructuredOutput::UnionOf[Integer, A1]
-  U2 = OpenAI::Helpers::StructuredOutput::UnionOf[:type, m2: M2, m3: M3]
+  U2 = OpenAI::Helpers::StructuredOutput::UnionOf[M2, M3]
   U3 = OpenAI::Helpers::StructuredOutput::UnionOf[A1, A1]
 
   def test_coerce
@@ -78,18 +79,21 @@ def test_to_schema
       A1 => {type: "array", items: {type: "string"}},
       OpenAI::Helpers::StructuredOutput::ArrayOf[String, nil?: true, doc: "a1"] => {
         type: "array",
-        items: {type: %w[string null]},
-        description: "a1"
+        items: {type: %w[string null], description: "a1"}
       },
       E1 => {type: "string", enum: ["one"]},
       M1 => {
         type: "object",
         properties: {
-          a: {type: "string"},
+          a: {type: "string", description: "dog"},
           b: {type: %w[integer null]},
-          c: {anyOf: [{type: "string", enum: %w[one]}, {type: "null"}]}
+          c: {
+            anyOf: [{type: "string", enum: ["one"]}, {type: "null"}],
+            description: "dog"
+          },
+          d: {description: "dog", type: "string", enum: ["one"]}
         },
-        required: %w[a b c],
+        required: %w[a b c d],
         additionalProperties: false
       },
       U1 => {
@@ -162,8 +166,9 @@ class M10 < OpenAI::Helpers::StructuredOutput::BaseModel
 
   class M11 < OpenAI::Helpers::StructuredOutput::BaseModel
     required :a, U3
-    required :b, A1
+    required :b, A1, doc: "dog"
     required :c, A1
+    required :d, A1, doc: "dawg"
   end
 
   def test_definition_reusing
@@ -311,20 +316,20 @@ def test_definition_reusing
         ]
       },
       M11 => {
-        :$defs => {".a/?.0/[]" => {type: "array", items: {type: "string"}}},
-        :type => "object",
-        :properties => {
+        type: "object",
+        properties: {
           a: {
             anyOf: [
               {type: "array", items: {type: "string"}},
               {type: "array", items: {type: "string"}}
             ]
           },
-          b: {:$ref => "#/$defs/.a/?.0/[]"},
-          c: {:$ref => "#/$defs/.a/?.0/[]"}
+          b: {description: "dog", type: "array", items: {type: "string"}},
+          c: {type: "array", items: {type: "string"}},
+          d: {description: "dawg", type: "array", items: {type: "string"}}
         },
-        :required => %w[a b c],
-        :additionalProperties => false
+        required: %w[a b c d],
+        additionalProperties: false
       }
     }
 
diff --git a/test/openai/resources/audio/speech_test.rb b/test/openai/resources/audio/speech_test.rb
index f50614b3..af4189d5 100644
--- a/test/openai/resources/audio/speech_test.rb
+++ b/test/openai/resources/audio/speech_test.rb
@@ -4,7 +4,7 @@
 
 class OpenAI::Test::Resources::Audio::SpeechTest < OpenAI::Test::ResourceTest
   def test_create_required_params
-    skip("skipped: test server currently has no support for method content-type")
+    skip("Prism doesn't support application/octet-stream responses")
 
     response = @openai.audio.speech.create(input: "input", model: :"tts-1", voice: :alloy)
 
diff --git a/test/openai/resources/containers/files/content_test.rb b/test/openai/resources/containers/files/content_test.rb
index 4d4252d4..0a57b6cb 100644
--- a/test/openai/resources/containers/files/content_test.rb
+++ b/test/openai/resources/containers/files/content_test.rb
@@ -4,7 +4,7 @@
 
 class OpenAI::Test::Resources::Containers::Files::ContentTest < OpenAI::Test::ResourceTest
   def test_retrieve_required_params
-    skip("skipped: test server currently has no support for method content-type")
+    skip("Prism doesn't support application/binary responses")
 
     response = @openai.containers.files.content.retrieve("file_id", container_id: "container_id")
 
diff --git a/test/openai/resources/files_test.rb b/test/openai/resources/files_test.rb
index de03395e..5833751a 100644
--- a/test/openai/resources/files_test.rb
+++ b/test/openai/resources/files_test.rb
@@ -93,7 +93,7 @@ def test_delete
   end
 
   def test_content
-    skip("skipped: test server currently has no support for method content-type")
+    skip("Prism doesn't support application/binary responses")
 
     response = @openai.files.content("file_id")