POC for adding content_parts to GetChatCompletions

christothes · christothes · commit af456ab0dadc · 2025-08-11T15:56:07.000-07:00
diff --git a/specification/base/typespec/chat/models.tsp b/specification/base/typespec/chat/models.tsp
@@ -719,6 +719,8 @@ model ChatCompletionResponseMessage {
   /** The contents of the message. */
   content: string | null;
 
+  content_parts?: ChatCompletionRequestMessageContentPart[] | null;
+
   /** The refusal message generated by the model. */
   refusal: string | null;
 
diff --git a/src/Custom/Chat/OpenAIChatModelFactory.cs b/src/Custom/Chat/OpenAIChatModelFactory.cs
@@ -69,7 +69,9 @@ public static ChatCompletion ChatCompletion(
         refusalTokenLogProbabilities ??= new List<ChatTokenLogProbabilityDetails>();
         messageAnnotations ??= new List<ChatMessageAnnotation>();
 
-        InternalChatCompletionResponseMessage message = new(
+        InternalChatCompletionResponseMessage message =
+        new(
+            null,
             refusal,
             toolCalls.ToList(),
             messageAnnotations.ToList(),
diff --git a/src/Generated/Models/Chat/ChatCompletionMessageListDatum.Serialization.cs b/src/Generated/Models/Chat/ChatCompletionMessageListDatum.Serialization.cs
@@ -12,7 +12,7 @@ namespace OpenAI.Chat
 {
     public partial class ChatCompletionMessageListDatum : IJsonModel<ChatCompletionMessageListDatum>
     {
-        internal ChatCompletionMessageListDatum() : this(null, null, null, null, null, null, default, null, null)
+        internal ChatCompletionMessageListDatum() : this(null, null, null, null, null, null, null, default, null, null)
         {
         }
 
@@ -42,6 +42,16 @@ protected virtual void JsonModelWriteCore(Utf8JsonWriter writer, ModelReaderWrit
                     writer.WriteNull("content"u8);
                 }
             }
+            if (Optional.IsCollectionDefined(ContentParts) && _additionalBinaryDataProperties?.ContainsKey("content_parts") != true)
+            {
+                writer.WritePropertyName("content_parts"u8);
+                writer.WriteStartArray();
+                foreach (ChatMessageContentPart item in ContentParts)
+                {
+                    writer.WriteObjectValue(item, options);
+                }
+                writer.WriteEndArray();
+            }
             if (_additionalBinaryDataProperties?.ContainsKey("refusal") != true)
             {
                 if (Optional.IsDefined(Refusal))
@@ -138,6 +148,7 @@ internal static ChatCompletionMessageListDatum DeserializeChatCompletionMessageL
                 return null;
             }
             string content = default;
+            IList<ChatMessageContentPart> contentParts = default;
             string refusal = default;
             IReadOnlyList<ChatToolCall> toolCalls = default;
             IReadOnlyList<ChatMessageAnnotation> annotations = default;
@@ -158,6 +169,20 @@ internal static ChatCompletionMessageListDatum DeserializeChatCompletionMessageL
                     content = prop.Value.GetString();
                     continue;
                 }
+                if (prop.NameEquals("content_parts"u8))
+                {
+                    if (prop.Value.ValueKind == JsonValueKind.Null)
+                    {
+                        continue;
+                    }
+                    List<ChatMessageContentPart> array = new List<ChatMessageContentPart>();
+                    foreach (var item in prop.Value.EnumerateArray())
+                    {
+                        array.Add(ChatMessageContentPart.DeserializeChatMessageContentPart(item, options));
+                    }
+                    contentParts = array;
+                    continue;
+                }
                 if (prop.NameEquals("refusal"u8))
                 {
                     if (prop.Value.ValueKind == JsonValueKind.Null)
@@ -230,6 +255,7 @@ internal static ChatCompletionMessageListDatum DeserializeChatCompletionMessageL
             }
             return new ChatCompletionMessageListDatum(
                 content,
+                contentParts ?? new ChangeTrackingList<ChatMessageContentPart>(),
                 refusal,
                 toolCalls ?? new ChangeTrackingList<ChatToolCall>(),
                 annotations ?? new ChangeTrackingList<ChatMessageAnnotation>(),
diff --git a/src/Generated/Models/Chat/ChatCompletionMessageListDatum.cs b/src/Generated/Models/Chat/ChatCompletionMessageListDatum.cs
@@ -17,17 +17,19 @@ public partial class ChatCompletionMessageListDatum
         internal ChatCompletionMessageListDatum(string content, string refusal, string id, ChatMessageRole role)
         {
             Content = content;
+            ContentParts = new ChangeTrackingList<ChatMessageContentPart>();
             Refusal = refusal;
             ToolCalls = new ChangeTrackingList<ChatToolCall>();
             Annotations = new ChangeTrackingList<ChatMessageAnnotation>();
             Id = id;
             Role = role;
         }
 
-        internal ChatCompletionMessageListDatum(string content, string refusal, IReadOnlyList<ChatToolCall> toolCalls, IReadOnlyList<ChatMessageAnnotation> annotations, InternalChatCompletionResponseMessageFunctionCall functionCall, string id, ChatMessageRole role, ChatOutputAudio outputAudio, IDictionary<string, BinaryData> additionalBinaryDataProperties)
+        internal ChatCompletionMessageListDatum(string content, IList<ChatMessageContentPart> contentParts, string refusal, IReadOnlyList<ChatToolCall> toolCalls, IReadOnlyList<ChatMessageAnnotation> annotations, InternalChatCompletionResponseMessageFunctionCall functionCall, string id, ChatMessageRole role, ChatOutputAudio outputAudio, IDictionary<string, BinaryData> additionalBinaryDataProperties)
         {
             // Plugin customization: ensure initialization of collections
             Content = content;
+            ContentParts = contentParts ?? new ChangeTrackingList<ChatMessageContentPart>();
             Refusal = refusal;
             ToolCalls = toolCalls ?? new ChangeTrackingList<ChatToolCall>();
             Annotations = annotations ?? new ChangeTrackingList<ChatMessageAnnotation>();
@@ -40,6 +42,8 @@ internal ChatCompletionMessageListDatum(string content, string refusal, IReadOnl
 
         public string Content { get; }
 
+        public IList<ChatMessageContentPart> ContentParts { get; }
+
         public string Refusal { get; }
 
         public IReadOnlyList<ChatToolCall> ToolCalls { get; }
diff --git a/src/Generated/Models/Chat/InternalChatCompletionRequestMessageContentPartAudio.cs b/src/Generated/Models/Chat/InternalChatCompletionRequestMessageContentPartAudio.cs
@@ -22,6 +22,6 @@ internal InternalChatCompletionRequestMessageContentPartAudio(IDictionary<string
             InputAudio = inputAudio;
         }
 
-        internal InternalChatCompletionRequestMessageContentPartAudioInputAudio InputAudio { get; }
+        internal InternalChatCompletionRequestMessageContentPartAudioInputAudio InputAudio { get; set; }
     }
 }
diff --git a/src/Generated/Models/Chat/InternalChatCompletionRequestMessageContentPartAudioInputAudio.cs b/src/Generated/Models/Chat/InternalChatCompletionRequestMessageContentPartAudioInputAudio.cs
@@ -27,9 +27,9 @@ internal InternalChatCompletionRequestMessageContentPartAudioInputAudio(BinaryDa
             _additionalBinaryDataProperties = additionalBinaryDataProperties;
         }
 
-        public BinaryData Data { get; }
+        public BinaryData Data { get; set; }
 
-        public ChatInputAudioFormat Format { get; }
+        public ChatInputAudioFormat Format { get; set; }
 
         internal IDictionary<string, BinaryData> SerializedAdditionalRawData
         {
diff --git a/src/Generated/Models/Chat/InternalChatCompletionRequestMessageContentPartFile.cs b/src/Generated/Models/Chat/InternalChatCompletionRequestMessageContentPartFile.cs
@@ -22,6 +22,6 @@ internal InternalChatCompletionRequestMessageContentPartFile(IDictionary<string,
             File = @file;
         }
 
-        internal InternalChatCompletionRequestMessageContentPartFileFile File { get; }
+        internal InternalChatCompletionRequestMessageContentPartFileFile File { get; set; }
     }
 }
diff --git a/src/Generated/Models/Chat/InternalChatCompletionRequestMessageContentPartImage.cs b/src/Generated/Models/Chat/InternalChatCompletionRequestMessageContentPartImage.cs
@@ -22,6 +22,6 @@ internal InternalChatCompletionRequestMessageContentPartImage(IDictionary<string
             ImageUrl = imageUrl;
         }
 
-        internal InternalChatCompletionRequestMessageContentPartImageImageUrl ImageUrl { get; }
+        internal InternalChatCompletionRequestMessageContentPartImageImageUrl ImageUrl { get; set; }
     }
 }
diff --git a/src/Generated/Models/Chat/InternalChatCompletionResponseMessage.Serialization.cs b/src/Generated/Models/Chat/InternalChatCompletionResponseMessage.Serialization.cs
@@ -12,7 +12,7 @@ namespace OpenAI.Chat
 {
     internal partial class InternalChatCompletionResponseMessage : IJsonModel<InternalChatCompletionResponseMessage>
     {
-        internal InternalChatCompletionResponseMessage() : this(null, null, null, null, default, null, null, null)
+        internal InternalChatCompletionResponseMessage() : this(null, null, null, null, null, default, null, null, null)
         {
         }
 
@@ -30,6 +30,16 @@ protected virtual void JsonModelWriteCore(Utf8JsonWriter writer, ModelReaderWrit
             {
                 throw new FormatException($"The model {nameof(InternalChatCompletionResponseMessage)} does not support writing '{format}' format.");
             }
+            if (Optional.IsCollectionDefined(ContentParts) && _additionalBinaryDataProperties?.ContainsKey("content_parts") != true)
+            {
+                writer.WritePropertyName("content_parts"u8);
+                writer.WriteStartArray();
+                foreach (ChatMessageContentPart item in ContentParts)
+                {
+                    writer.WriteObjectValue(item, options);
+                }
+                writer.WriteEndArray();
+            }
             if (_additionalBinaryDataProperties?.ContainsKey("refusal") != true)
             {
                 if (Optional.IsDefined(Refusal))
@@ -132,6 +142,7 @@ internal static InternalChatCompletionResponseMessage DeserializeInternalChatCom
             {
                 return null;
             }
+            IList<ChatMessageContentPart> contentParts = default;
             string refusal = default;
             IReadOnlyList<ChatToolCall> toolCalls = default;
             IReadOnlyList<ChatMessageAnnotation> annotations = default;
@@ -142,6 +153,20 @@ internal static InternalChatCompletionResponseMessage DeserializeInternalChatCom
             IDictionary<string, BinaryData> additionalBinaryDataProperties = new ChangeTrackingDictionary<string, BinaryData>();
             foreach (var prop in element.EnumerateObject())
             {
+                if (prop.NameEquals("content_parts"u8))
+                {
+                    if (prop.Value.ValueKind == JsonValueKind.Null)
+                    {
+                        continue;
+                    }
+                    List<ChatMessageContentPart> array = new List<ChatMessageContentPart>();
+                    foreach (var item in prop.Value.EnumerateArray())
+                    {
+                        array.Add(ChatMessageContentPart.DeserializeChatMessageContentPart(item, options));
+                    }
+                    contentParts = array;
+                    continue;
+                }
                 if (prop.NameEquals("refusal"u8))
                 {
                     if (prop.Value.ValueKind == JsonValueKind.Null)
@@ -213,6 +238,7 @@ internal static InternalChatCompletionResponseMessage DeserializeInternalChatCom
                 additionalBinaryDataProperties.Add(prop.Name, BinaryData.FromString(prop.Value.GetRawText()));
             }
             return new InternalChatCompletionResponseMessage(
+                contentParts ?? new ChangeTrackingList<ChatMessageContentPart>(),
                 refusal,
                 toolCalls ?? new ChangeTrackingList<ChatToolCall>(),
                 annotations ?? new ChangeTrackingList<ChatMessageAnnotation>(),
diff --git a/src/Generated/Models/Chat/InternalChatCompletionResponseMessage.cs b/src/Generated/Models/Chat/InternalChatCompletionResponseMessage.cs
@@ -15,16 +15,18 @@ internal partial class InternalChatCompletionResponseMessage
         internal InternalChatCompletionResponseMessage(string refusal, ChatMessageRole role, ChatMessageContent content)
         {
             // Plugin customization: ensure initialization of collections
+            ContentParts = new ChangeTrackingList<ChatMessageContentPart>();
             Refusal = refusal;
             ToolCalls = new ChangeTrackingList<ChatToolCall>();
             Annotations = new ChangeTrackingList<ChatMessageAnnotation>();
             Role = role;
             Content = content ?? new ChatMessageContent();
         }
 
-        internal InternalChatCompletionResponseMessage(string refusal, IReadOnlyList<ChatToolCall> toolCalls, IReadOnlyList<ChatMessageAnnotation> annotations, ChatOutputAudio audio, ChatMessageRole role, ChatMessageContent content, ChatFunctionCall functionCall, IDictionary<string, BinaryData> additionalBinaryDataProperties)
+        internal InternalChatCompletionResponseMessage(IList<ChatMessageContentPart> contentParts, string refusal, IReadOnlyList<ChatToolCall> toolCalls, IReadOnlyList<ChatMessageAnnotation> annotations, ChatOutputAudio audio, ChatMessageRole role, ChatMessageContent content, ChatFunctionCall functionCall, IDictionary<string, BinaryData> additionalBinaryDataProperties)
         {
             // Plugin customization: ensure initialization of collections
+            ContentParts = contentParts ?? new ChangeTrackingList<ChatMessageContentPart>();
             Refusal = refusal;
             ToolCalls = toolCalls ?? new ChangeTrackingList<ChatToolCall>();
             Annotations = annotations ?? new ChangeTrackingList<ChatMessageAnnotation>();
@@ -35,6 +37,8 @@ internal InternalChatCompletionResponseMessage(string refusal, IReadOnlyList<Cha
             _additionalBinaryDataProperties = additionalBinaryDataProperties;
         }
 
+        public IList<ChatMessageContentPart> ContentParts { get; }
+
         public string Refusal { get; }
 
         public IReadOnlyList<ChatToolCall> ToolCalls { get; }
diff --git a/src/Generated/OpenAIModelFactory.cs b/src/Generated/OpenAIModelFactory.cs
@@ -177,6 +177,11 @@ public static AudioTranslation AudioTranslation(string language = default, strin
                 additionalBinaryDataProperties: null);
         }
 
+        public static ChatMessageContentPart ChatMessageContentPart()
+        {
+            return new InternalUnknownChatCompletionRequestMessageContentPart(additionalBinaryDataProperties: null);
+        }
+
         public static ChatOutputAudio ChatOutputAudio(string id = default, DateTimeOffset expiresAt = default, string transcript = default, BinaryData audioBytes = default)
         {
             return new ChatOutputAudio(id, expiresAt, transcript, audioBytes, additionalBinaryDataProperties: null);
@@ -220,11 +225,6 @@ public static ChatMessage ChatMessage(ChatMessageContent content = default, stri
             return new InternalUnknownChatMessage(content, role.ToChatMessageRole(), additionalBinaryDataProperties: null);
         }
 
-        public static ChatMessageContentPart ChatMessageContentPart()
-        {
-            return new InternalUnknownChatCompletionRequestMessageContentPart(additionalBinaryDataProperties: null);
-        }
-
         public static SystemChatMessage SystemChatMessage(ChatMessageContent content = default, string participantName = default)
         {
             return new SystemChatMessage(content, ChatMessageRole.System, additionalBinaryDataProperties: null, participantName);
diff --git a/tests/Chat/ChatStoreTests.cs b/tests/Chat/ChatStoreTests.cs
@@ -694,12 +694,15 @@ public async Task GetChatCompletionMessagesWithPagination()
         ChatClient client = GetTestClient();
 
         // Create completion with multiple messages (conversation with tool calls)
+        // and one with multiple content parts
         List<ChatMessage> conversationMessages = new()
         {
             new UserChatMessage("What's the weather like today? Use the weather tool."),
             new UserChatMessage("Name something I could do outside in this weather."),
             new UserChatMessage("Name something else I could do outside in this weather."),
-            new UserChatMessage("Name something yet another thing I could do outside in this weather.")
+            new UserChatMessage([
+                ChatMessageContentPart.CreateTextPart("Whose logo is this?: "),
+                ChatMessageContentPart.CreateImagePart(new Uri("https://upload.wikimedia.org/wikipedia/commons/c/c3/Openai.png"))]),
         };
 
         // Add function definition to trigger more back-and-forth
@@ -741,15 +744,26 @@ await RetryWithExponentialBackoffAsync(async () =>
                 PageSizeLimit = 2
             };
 
+            bool foundContentParts = false;
+
             await foreach (var message in client.GetChatCompletionMessagesAsync(completion.Id, options))
             {
                 totalMessages++;
                 lastMessageId = message.Id;
+
+                // Check if the message contains any content parts
+                if (message.ContentParts.Count > 0)
+                {
+                    foundContentParts = true;
+                    Assert.That(message.ContentParts[0].Text, Is.EqualTo("Whose logo is this?: "));
+                    Assert.That(message.ContentParts[1].ImageBytes, Is.Not.Null);
+                }
                 Assert.That(message.Id, Is.Not.Null.And.Not.Empty);
 
                 if (totalMessages >= 4) break; // Get a few pages worth
             }
 
+            Assert.That(foundContentParts, Is.True);
             Assert.That(totalMessages, Is.GreaterThan(3));
             Assert.That(lastMessageId, Is.Not.Null);
         });
diff --git a/tspCodeModel.json b/tspCodeModel.json

Original file line number	Diff line number	Diff line change
`@@ -12,7 +12,7 @@ namespace OpenAI.Chat`
`12`	`12`	`{`
`13`	`13`	`public partial class ChatCompletionMessageListDatum : IJsonModel<ChatCompletionMessageListDatum>`
`14`	`14`	`{`
`15`		`- internal ChatCompletionMessageListDatum() : this(null, null, null, null, null, null, default, null, null)`
	`15`	`+ internal ChatCompletionMessageListDatum() : this(null, null, null, null, null, null, null, default, null, null)`
`16`	`16`	`{`
`17`	`17`	`}`
`18`	`18`
`@@ -42,6 +42,16 @@ protected virtual void JsonModelWriteCore(Utf8JsonWriter writer, ModelReaderWrit`
`42`	`42`	`writer.WriteNull("content"u8);`
`43`	`43`	`}`
`44`	`44`	`}`
	`45`	`+ if (Optional.IsCollectionDefined(ContentParts) && _additionalBinaryDataProperties?.ContainsKey("content_parts") != true)`
	`46`	`+ {`
	`47`	`+ writer.WritePropertyName("content_parts"u8);`
	`48`	`+ writer.WriteStartArray();`
	`49`	`+ foreach (ChatMessageContentPart item in ContentParts)`
	`50`	`+ {`
	`51`	`+ writer.WriteObjectValue(item, options);`
	`52`	`+ }`
	`53`	`+ writer.WriteEndArray();`
	`54`	`+ }`
`45`	`55`	`if (_additionalBinaryDataProperties?.ContainsKey("refusal") != true)`
`46`	`56`	`{`
`47`	`57`	`if (Optional.IsDefined(Refusal))`
`@@ -138,6 +148,7 @@ internal static ChatCompletionMessageListDatum DeserializeChatCompletionMessageL`
`138`	`148`	`return null;`
`139`	`149`	`}`
`140`	`150`	`string content = default;`
	`151`	`+ IList<ChatMessageContentPart> contentParts = default;`
`141`	`152`	`string refusal = default;`
`142`	`153`	`IReadOnlyList<ChatToolCall> toolCalls = default;`
`143`	`154`	`IReadOnlyList<ChatMessageAnnotation> annotations = default;`
`@@ -158,6 +169,20 @@ internal static ChatCompletionMessageListDatum DeserializeChatCompletionMessageL`
`158`	`169`	`content = prop.Value.GetString();`
`159`	`170`	`continue;`
`160`	`171`	`}`
	`172`	`+ if (prop.NameEquals("content_parts"u8))`
	`173`	`+ {`
	`174`	`+ if (prop.Value.ValueKind == JsonValueKind.Null)`
	`175`	`+ {`
	`176`	`+ continue;`
	`177`	`+ }`
	`178`	`+ List<ChatMessageContentPart> array = new List<ChatMessageContentPart>();`
	`179`	`+ foreach (var item in prop.Value.EnumerateArray())`
	`180`	`+ {`
	`181`	`+ array.Add(ChatMessageContentPart.DeserializeChatMessageContentPart(item, options));`
	`182`	`+ }`
	`183`	`+ contentParts = array;`
	`184`	`+ continue;`
	`185`	`+ }`
`161`	`186`	`if (prop.NameEquals("refusal"u8))`
`162`	`187`	`{`
`163`	`188`	`if (prop.Value.ValueKind == JsonValueKind.Null)`
`@@ -230,6 +255,7 @@ internal static ChatCompletionMessageListDatum DeserializeChatCompletionMessageL`
`230`	`255`	`}`
`231`	`256`	`return new ChatCompletionMessageListDatum(`
`232`	`257`	`content,`
	`258`	`+ contentParts ?? new ChangeTrackingList<ChatMessageContentPart>(),`
`233`	`259`	`refusal,`
`234`	`260`	`toolCalls ?? new ChangeTrackingList<ChatToolCall>(),`
`235`	`261`	`annotations ?? new ChangeTrackingList<ChatMessageAnnotation>(),`
Original file line number	Diff line number	Diff line change
`@@ -22,6 +22,6 @@ internal InternalChatCompletionRequestMessageContentPartAudio(IDictionary<string`
`22`	`22`	`InputAudio = inputAudio;`
`23`	`23`	`}`
`24`	`24`
`25`		`- internal InternalChatCompletionRequestMessageContentPartAudioInputAudio InputAudio { get; }`
	`25`	`+ internal InternalChatCompletionRequestMessageContentPartAudioInputAudio InputAudio { get; set; }`
`26`	`26`	`}`
`27`	`27`	`}`
Original file line number	Diff line number	Diff line change
`@@ -27,9 +27,9 @@ internal InternalChatCompletionRequestMessageContentPartAudioInputAudio(BinaryDa`
`27`	`27`	`_additionalBinaryDataProperties = additionalBinaryDataProperties;`
`28`	`28`	`}`
`29`	`29`
`30`		`- public BinaryData Data { get; }`
	`30`	`+ public BinaryData Data { get; set; }`
`31`	`31`
`32`		`- public ChatInputAudioFormat Format { get; }`
	`32`	`+ public ChatInputAudioFormat Format { get; set; }`
`33`	`33`
`34`	`34`	`internal IDictionary<string, BinaryData> SerializedAdditionalRawData`
`35`	`35`	`{`