diff --git a/src/Libraries/Microsoft.Extensions.AI.OpenAI/MicrosoftExtensionsAIAssistantsExtensions.cs b/src/Libraries/Microsoft.Extensions.AI.OpenAI/MicrosoftExtensionsAIAssistantsExtensions.cs
new file mode 100644
index 00000000000..900883c6d43
--- /dev/null
+++ b/src/Libraries/Microsoft.Extensions.AI.OpenAI/MicrosoftExtensionsAIAssistantsExtensions.cs
@@ -0,0 +1,19 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using Microsoft.Extensions.AI;
+using Microsoft.Shared.Diagnostics;
+
+namespace OpenAI.Assistants;
+
+/// <summary>Provides extension methods for working with content associated with OpenAI.Assistants.</summary>
+public static class MicrosoftExtensionsAIAssistantsExtensions
+{
+    /// <summary>Creates an OpenAI <see cref="FunctionToolDefinition"/> from an <see cref="AIFunction"/>.</summary>
+    /// <param name="function">The function to convert.</param>
+    /// <returns>An OpenAI <see cref="FunctionToolDefinition"/> representing <paramref name="function"/>.</returns>
+    /// <exception cref="ArgumentNullException"><paramref name="function"/> is <see langword="null"/>.</exception>
+    public static FunctionToolDefinition AsOpenAIAssistantsFunctionToolDefinition(this AIFunction function) =>
+        OpenAIAssistantsChatClient.ToOpenAIAssistantsFunctionToolDefinition(Throw.IfNull(function));
+}
diff --git a/src/Libraries/Microsoft.Extensions.AI.OpenAI/MicrosoftExtensionsAIChatExtensions.cs b/src/Libraries/Microsoft.Extensions.AI.OpenAI/MicrosoftExtensionsAIChatExtensions.cs
new file mode 100644
index 00000000000..c7eb3b2e03e
--- /dev/null
+++ b/src/Libraries/Microsoft.Extensions.AI.OpenAI/MicrosoftExtensionsAIChatExtensions.cs
@@ -0,0 +1,33 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Collections.Generic;
+using Microsoft.Extensions.AI;
+using Microsoft.Shared.Diagnostics;
+
+namespace OpenAI.Chat;
+
+/// <summary>Provides extension methods for working with content associated with OpenAI.Chat.</summary>
+public static class MicrosoftExtensionsAIChatExtensions
+{
+    /// <summary>Creates an OpenAI <see cref="ChatTool"/> from an <see cref="AIFunction"/>.</summary>
+    /// <param name="function">The function to convert.</param>
+    /// <returns>An OpenAI <see cref="ChatTool"/> representing <paramref name="function"/>.</returns>
+    /// <exception cref="ArgumentNullException"><paramref name="function"/> is <see langword="null"/>.</exception>
+    public static ChatTool AsOpenAIChatTool(this AIFunction function) =>
+        OpenAIChatClient.ToOpenAIChatTool(Throw.IfNull(function));
+
+    /// <summary>Creates a sequence of OpenAI <see cref="ChatMessage"/> instances from the specified input messages.</summary>
+    /// <param name="messages">The input messages to convert.</param>
+    /// <returns>A sequence of OpenAI chat messages.</returns>
+    public static IEnumerable<ChatMessage> AsOpenAIChatMessages(this IEnumerable<Microsoft.Extensions.AI.ChatMessage> messages) =>
+        OpenAIChatClient.ToOpenAIChatMessages(Throw.IfNull(messages), chatOptions: null);
+
+    /// <summary>Creates a Microsoft.Extensions.AI <see cref="ChatResponse"/> from a <see cref="ChatCompletion"/>.</summary>
+    /// <param name="chatCompletion">The <see cref="ChatCompletion"/> to convert to a <see cref="ChatResponse"/>.</param>
+    /// <param name="options">The options employed in the creation of the response.</param>
+    /// <returns>A converted <see cref="ChatResponse"/>.</returns>
+    public static ChatResponse AsChatResponse(this ChatCompletion chatCompletion, ChatCompletionOptions? options = null) =>
+        OpenAIChatClient.FromOpenAIChatCompletion(Throw.IfNull(chatCompletion), options);
+}
diff --git a/src/Libraries/Microsoft.Extensions.AI.OpenAI/MicrosoftExtensionsAIRealtimeExtensions.cs b/src/Libraries/Microsoft.Extensions.AI.OpenAI/MicrosoftExtensionsAIRealtimeExtensions.cs
new file mode 100644
index 00000000000..ad180e96b1e
--- /dev/null
+++ b/src/Libraries/Microsoft.Extensions.AI.OpenAI/MicrosoftExtensionsAIRealtimeExtensions.cs
@@ -0,0 +1,19 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using Microsoft.Extensions.AI;
+using Microsoft.Shared.Diagnostics;
+
+namespace OpenAI.Realtime;
+
+/// <summary>Provides extension methods for working with content associated with OpenAI.Realtime.</summary>
+public static class MicrosoftExtensionsAIRealtimeExtensions
+{
+    /// <summary>Creates an OpenAI <see cref="ConversationFunctionTool"/> from an <see cref="AIFunction"/>.</summary>
+    /// <param name="function">The function to convert.</param>
+    /// <returns>An OpenAI <see cref="ConversationFunctionTool"/> representing <paramref name="function"/>.</returns>
+    /// <exception cref="ArgumentNullException"><paramref name="function"/> is <see langword="null"/>.</exception>
+    public static ConversationFunctionTool AsOpenAIConversationFunctionTool(this AIFunction function) =>
+        OpenAIRealtimeConversationClient.ToOpenAIConversationFunctionTool(Throw.IfNull(function));
+}
diff --git a/src/Libraries/Microsoft.Extensions.AI.OpenAI/MicrosoftExtensionsAIResponsesExtensions.cs b/src/Libraries/Microsoft.Extensions.AI.OpenAI/MicrosoftExtensionsAIResponsesExtensions.cs
new file mode 100644
index 00000000000..e54b3092c5a
--- /dev/null
+++ b/src/Libraries/Microsoft.Extensions.AI.OpenAI/MicrosoftExtensionsAIResponsesExtensions.cs
@@ -0,0 +1,33 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Collections.Generic;
+using Microsoft.Extensions.AI;
+using Microsoft.Shared.Diagnostics;
+
+namespace OpenAI.Responses;
+
+/// <summary>Provides extension methods for working with content associated with OpenAI.Responses.</summary>
+public static class MicrosoftExtensionsAIResponsesExtensions
+{
+    /// <summary>Creates an OpenAI <see cref="ResponseTool"/> from an <see cref="AIFunction"/>.</summary>
+    /// <param name="function">The function to convert.</param>
+    /// <returns>An OpenAI <see cref="ResponseTool"/> representing <paramref name="function"/>.</returns>
+    /// <exception cref="ArgumentNullException"><paramref name="function"/> is <see langword="null"/>.</exception>
+    public static ResponseTool AsOpenAIResponseTool(this AIFunction function) =>
+        OpenAIResponsesChatClient.ToResponseTool(Throw.IfNull(function));
+
+    /// <summary>Creates a sequence of OpenAI <see cref="ResponseItem"/> instances from the specified input messages.</summary>
+    /// <param name="messages">The input messages to convert.</param>
+    /// <returns>A sequence of OpenAI response items.</returns>
+    public static IEnumerable<ResponseItem> AsOpenAIResponseItems(this IEnumerable<ChatMessage> messages) =>
+        OpenAIResponsesChatClient.ToOpenAIResponseItems(Throw.IfNull(messages));
+
+    /// <summary>Creates a Microsoft.Extensions.AI <see cref="ChatResponse"/> from an <see cref="OpenAIResponse"/>.</summary>
+    /// <param name="response">The <see cref="OpenAIResponse"/> to convert to a <see cref="ChatResponse"/>.</param>
+    /// <param name="options">The options employed in the creation of the response.</param>
+    /// <returns>A converted <see cref="ChatResponse"/>.</returns>
+    public static ChatResponse AsChatResponse(this OpenAIResponse response, ResponseCreationOptions? options = null) =>
+        OpenAIResponsesChatClient.FromOpenAIResponse(Throw.IfNull(response), options);
+}
diff --git a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIAssistantChatClient.cs b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIAssistantsChatClient.cs
similarity index 96%
rename from src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIAssistantChatClient.cs
rename to src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIAssistantsChatClient.cs
index c1d59e30a68..46bc39ee278 100644
--- a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIAssistantChatClient.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIAssistantsChatClient.cs
@@ -26,8 +26,8 @@
 
 namespace Microsoft.Extensions.AI;
 
-/// <summary>Represents an <see cref="IChatClient"/> for an Azure.AI.Agents.Persistent <see cref="AssistantClient"/>.</summary>
-internal sealed class OpenAIAssistantChatClient : IChatClient
+/// <summary>Represents an <see cref="IChatClient"/> for an OpenAI <see cref="AssistantClient"/>.</summary>
+internal sealed class OpenAIAssistantsChatClient : IChatClient
 {
     /// <summary>The underlying <see cref="AssistantClient" />.</summary>
     private readonly AssistantClient _client;
@@ -44,8 +44,8 @@ internal sealed class OpenAIAssistantChatClient : IChatClient
     /// <summary>List of tools associated with the assistant.</summary>
     private IReadOnlyList<ToolDefinition>? _assistantTools;
 
-    /// <summary>Initializes a new instance of the <see cref="OpenAIAssistantChatClient"/> class for the specified <see cref="AssistantClient"/>.</summary>
-    public OpenAIAssistantChatClient(AssistantClient assistantClient, string assistantId, string? defaultThreadId)
+    /// <summary>Initializes a new instance of the <see cref="OpenAIAssistantsChatClient"/> class for the specified <see cref="AssistantClient"/>.</summary>
+    public OpenAIAssistantsChatClient(AssistantClient assistantClient, string assistantId, string? defaultThreadId)
     {
         _client = Throw.IfNull(assistantClient);
         _assistantId = Throw.IfNullOrWhitespace(assistantId);
@@ -62,6 +62,13 @@ public OpenAIAssistantChatClient(AssistantClient assistantClient, string assista
         _metadata = new("openai", providerUrl);
     }
 
+    /// <summary>Initializes a new instance of the <see cref="OpenAIAssistantsChatClient"/> class for the specified <see cref="AssistantClient"/>.</summary>
+    public OpenAIAssistantsChatClient(AssistantClient assistantClient, Assistant assistant, string? defaultThreadId)
+        : this(assistantClient, Throw.IfNull(assistant).Id, defaultThreadId)
+    {
+        _assistantTools = assistant.Tools;
+    }
+
     /// <inheritdoc />
     public object? GetService(Type serviceType, object? serviceKey = null) =>
         serviceType is null ? throw new ArgumentNullException(nameof(serviceType)) :
diff --git a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIChatClient.cs b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIChatClient.cs
index 52dfc3dc8af..9fc2f3cbeef 100644
--- a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIChatClient.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIChatClient.cs
@@ -17,6 +17,7 @@
 #pragma warning disable EA0011 // Consider removing unnecessary conditional access operator (?)
 #pragma warning disable S1067 // Expressions should not be too complex
 #pragma warning disable S3011 // Reflection should not be used to increase accessibility of classes, methods, or fields
+#pragma warning disable SA1202 // Elements should be ordered by access
 #pragma warning disable SA1204 // Static elements should appear before instance elements
 
 namespace Microsoft.Extensions.AI;
@@ -76,7 +77,7 @@ public async Task<ChatResponse> GetResponseAsync(
         // Make the call to OpenAI.
         var response = await _chatClient.CompleteChatAsync(openAIChatMessages, openAIOptions, cancellationToken).ConfigureAwait(false);
 
-        return FromOpenAIChatCompletion(response.Value, options, openAIOptions);
+        return FromOpenAIChatCompletion(response.Value, openAIOptions);
     }
 
     /// <inheritdoc />
@@ -430,7 +431,7 @@ private static string GetOutputAudioMimeType(ChatCompletionOptions? options) =>
             "mp3" or _ => "audio/mpeg",
         };
 
-    private static ChatResponse FromOpenAIChatCompletion(ChatCompletion openAICompletion, ChatOptions? options, ChatCompletionOptions chatCompletionOptions)
+    internal static ChatResponse FromOpenAIChatCompletion(ChatCompletion openAICompletion, ChatCompletionOptions? chatCompletionOptions)
     {
         _ = Throw.IfNull(openAICompletion);
 
@@ -461,17 +462,14 @@ private static ChatResponse FromOpenAIChatCompletion(ChatCompletion openAIComple
         }
 
         // Also manufacture function calling content items from any tool calls in the response.
-        if (options?.Tools is { Count: > 0 })
+        foreach (ChatToolCall toolCall in openAICompletion.ToolCalls)
         {
-            foreach (ChatToolCall toolCall in openAICompletion.ToolCalls)
+            if (!string.IsNullOrWhiteSpace(toolCall.FunctionName))
             {
-                if (!string.IsNullOrWhiteSpace(toolCall.FunctionName))
-                {
-                    var callContent = ParseCallContentFromBinaryData(toolCall.FunctionArguments, toolCall.Id, toolCall.FunctionName);
-                    callContent.RawRepresentation = toolCall;
+                var callContent = ParseCallContentFromBinaryData(toolCall.FunctionArguments, toolCall.Id, toolCall.FunctionName);
+                callContent.RawRepresentation = toolCall;
 
-                    returnMessage.Contents.Add(callContent);
-                }
+                returnMessage.Contents.Add(callContent);
             }
         }
 
diff --git a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIClientExtensions.cs b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIClientExtensions.cs
index 9f42fa88773..889998cc933 100644
--- a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIClientExtensions.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIClientExtensions.cs
@@ -8,20 +8,15 @@
 using System.Text.Json;
 using System.Text.Json.Nodes;
 using System.Text.Json.Serialization;
-using Microsoft.Shared.Diagnostics;
 using OpenAI;
 using OpenAI.Assistants;
 using OpenAI.Audio;
 using OpenAI.Chat;
 using OpenAI.Embeddings;
-using OpenAI.Realtime;
 using OpenAI.Responses;
 
 #pragma warning disable S103 // Lines should not be too long
-#pragma warning disable S1067 // Expressions should not be too complex
 #pragma warning disable SA1515 // Single-line comment should be preceded by blank line
-#pragma warning disable CA1305 // Specify IFormatProvider
-#pragma warning disable S1135 // Track uses of "TODO" tags
 
 namespace Microsoft.Extensions.AI;
 
@@ -120,7 +115,7 @@ public static IChatClient AsIChatClient(this ChatClient chatClient) =>
     /// <returns>An <see cref="IChatClient"/> that can be used to converse via the <see cref="OpenAIResponseClient"/>.</returns>
     /// <exception cref="ArgumentNullException"><paramref name="responseClient"/> is <see langword="null"/>.</exception>
     public static IChatClient AsIChatClient(this OpenAIResponseClient responseClient) =>
-        new OpenAIResponseChatClient(responseClient);
+        new OpenAIResponsesChatClient(responseClient);
 
     /// <summary>Gets an <see cref="IChatClient"/> for use with this <see cref="AssistantClient"/>.</summary>
     /// <param name="assistantClient">The <see cref="AssistantClient"/> instance to be accessed as an <see cref="IChatClient"/>.</param>
@@ -135,7 +130,21 @@ public static IChatClient AsIChatClient(this OpenAIResponseClient responseClient
     /// <exception cref="ArgumentNullException"><paramref name="assistantId"/> is <see langword="null"/>.</exception>
     /// <exception cref="ArgumentException"><paramref name="assistantId"/> is empty or composed entirely of whitespace.</exception>
     public static IChatClient AsIChatClient(this AssistantClient assistantClient, string assistantId, string? threadId = null) =>
-        new OpenAIAssistantChatClient(assistantClient, assistantId, threadId);
+        new OpenAIAssistantsChatClient(assistantClient, assistantId, threadId);
+
+    /// <summary>Gets an <see cref="IChatClient"/> for use with this <see cref="AssistantClient"/>.</summary>
+    /// <param name="assistantClient">The <see cref="AssistantClient"/> instance to be accessed as an <see cref="IChatClient"/>.</param>
+    /// <param name="assistant">The <see cref="Assistant"/> with which to interact.</param>
+    /// <param name="threadId">
+    /// An optional existing thread identifier for the chat session. This serves as a default, and may be overridden per call to
+    /// <see cref="IChatClient.GetResponseAsync"/> or <see cref="IChatClient.GetStreamingResponseAsync"/> via the <see cref="ChatOptions.ConversationId"/>
+    /// property. If no thread ID is provided via either mechanism, a new thread will be created for the request.
+    /// </param>
+    /// <returns>An <see cref="IChatClient"/> instance configured to interact with the specified agent and thread.</returns>
+    /// <exception cref="ArgumentNullException"><paramref name="assistantClient"/> is <see langword="null"/>.</exception>
+    /// <exception cref="ArgumentNullException"><paramref name="assistant"/> is <see langword="null"/>.</exception>
+    public static IChatClient AsIChatClient(this AssistantClient assistantClient, Assistant assistant, string? threadId = null) =>
+        new OpenAIAssistantsChatClient(assistantClient, assistant, threadId);
 
     /// <summary>Gets an <see cref="ISpeechToTextClient"/> for use with this <see cref="AudioClient"/>.</summary>
     /// <param name="audioClient">The client.</param>
@@ -153,48 +162,6 @@ public static ISpeechToTextClient AsISpeechToTextClient(this AudioClient audioCl
     public static IEmbeddingGenerator<string, Embedding<float>> AsIEmbeddingGenerator(this EmbeddingClient embeddingClient, int? defaultModelDimensions = null) =>
         new OpenAIEmbeddingGenerator(embeddingClient, defaultModelDimensions);
 
-    /// <summary>Creates an OpenAI <see cref="ChatTool"/> from an <see cref="AIFunction"/>.</summary>
-    /// <param name="function">The function to convert.</param>
-    /// <returns>An OpenAI <see cref="ChatTool"/> representing <paramref name="function"/>.</returns>
-    /// <exception cref="ArgumentNullException"><paramref name="function"/> is <see langword="null"/>.</exception>
-    public static ChatTool AsOpenAIChatTool(this AIFunction function) =>
-        OpenAIChatClient.ToOpenAIChatTool(Throw.IfNull(function));
-
-    /// <summary>Creates an OpenAI <see cref="FunctionToolDefinition"/> from an <see cref="AIFunction"/>.</summary>
-    /// <param name="function">The function to convert.</param>
-    /// <returns>An OpenAI <see cref="FunctionToolDefinition"/> representing <paramref name="function"/>.</returns>
-    /// <exception cref="ArgumentNullException"><paramref name="function"/> is <see langword="null"/>.</exception>
-    public static FunctionToolDefinition AsOpenAIAssistantsFunctionToolDefinition(this AIFunction function) =>
-        OpenAIAssistantChatClient.ToOpenAIAssistantsFunctionToolDefinition(Throw.IfNull(function));
-
-    /// <summary>Creates an OpenAI <see cref="ResponseTool"/> from an <see cref="AIFunction"/>.</summary>
-    /// <param name="function">The function to convert.</param>
-    /// <returns>An OpenAI <see cref="ResponseTool"/> representing <paramref name="function"/>.</returns>
-    /// <exception cref="ArgumentNullException"><paramref name="function"/> is <see langword="null"/>.</exception>
-    public static ResponseTool AsOpenAIResponseTool(this AIFunction function) =>
-        OpenAIResponseChatClient.ToResponseTool(Throw.IfNull(function));
-
-    /// <summary>Creates an OpenAI <see cref="ConversationFunctionTool"/> from an <see cref="AIFunction"/>.</summary>
-    /// <param name="function">The function to convert.</param>
-    /// <returns>An OpenAI <see cref="ConversationFunctionTool"/> representing <paramref name="function"/>.</returns>
-    /// <exception cref="ArgumentNullException"><paramref name="function"/> is <see langword="null"/>.</exception>
-    public static ConversationFunctionTool AsOpenAIConversationFunctionTool(this AIFunction function) =>
-        OpenAIRealtimeConversationClient.ToOpenAIConversationFunctionTool(Throw.IfNull(function));
-
-    /// <summary>Creates a sequence of OpenAI <see cref="OpenAI.Chat.ChatMessage"/> instances from the specified input messages.</summary>
-    /// <param name="messages">The input messages to convert.</param>
-    /// <returns>A sequence of OpenAI chat messages.</returns>
-    public static IEnumerable<OpenAI.Chat.ChatMessage> AsOpenAIChatMessages(this IEnumerable<ChatMessage> messages) =>
-        OpenAIChatClient.ToOpenAIChatMessages(Throw.IfNull(messages), chatOptions: null);
-
-    /// <summary>Creates a sequence of OpenAI <see cref="OpenAI.Responses.ResponseItem"/> instances from the specified input messages.</summary>
-    /// <param name="messages">The input messages to convert.</param>
-    /// <returns>A sequence of OpenAI response items.</returns>
-    public static IEnumerable<OpenAI.Responses.ResponseItem> AsOpenAIResponseItems(this IEnumerable<ChatMessage> messages) =>
-        OpenAIResponseChatClient.ToOpenAIResponseItems(Throw.IfNull(messages));
-
-    // TODO: Once we're ready to rely on C# 14 features, add an extension property ChatOptions.Strict.
-
     /// <summary>Gets whether the properties specify that strict schema handling is desired.</summary>
     internal static bool? HasStrict(IReadOnlyDictionary<string, object?>? additionalProperties) =>
         additionalProperties?.TryGetValue(StrictKey, out object? strictObj) is true &&
diff --git a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIEmbeddingGenerator.cs b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIEmbeddingGenerator.cs
index 004f6274265..a6c4af831ba 100644
--- a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIEmbeddingGenerator.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIEmbeddingGenerator.cs
@@ -8,7 +8,6 @@
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Shared.Diagnostics;
-using OpenAI;
 using OpenAI.Embeddings;
 
 #pragma warning disable S1067 // Expressions should not be too complex
diff --git a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponseChatClient.cs b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponsesChatClient.cs
similarity index 98%
rename from src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponseChatClient.cs
rename to src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponsesChatClient.cs
index b5ba36b5e1a..60d0e10a159 100644
--- a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponseChatClient.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponsesChatClient.cs
@@ -23,7 +23,7 @@
 namespace Microsoft.Extensions.AI;
 
 /// <summary>Represents an <see cref="IChatClient"/> for an <see cref="OpenAIResponseClient"/>.</summary>
-internal sealed class OpenAIResponseChatClient : IChatClient
+internal sealed class OpenAIResponsesChatClient : IChatClient
 {
     /// <summary>Metadata about the client.</summary>
     private readonly ChatClientMetadata _metadata;
@@ -31,10 +31,10 @@ internal sealed class OpenAIResponseChatClient : IChatClient
     /// <summary>The underlying <see cref="OpenAIResponseClient" />.</summary>
     private readonly OpenAIResponseClient _responseClient;
 
-    /// <summary>Initializes a new instance of the <see cref="OpenAIResponseChatClient"/> class for the specified <see cref="OpenAIResponseClient"/>.</summary>
+    /// <summary>Initializes a new instance of the <see cref="OpenAIResponsesChatClient"/> class for the specified <see cref="OpenAIResponseClient"/>.</summary>
     /// <param name="responseClient">The underlying client.</param>
     /// <exception cref="ArgumentNullException"><paramref name="responseClient"/> is <see langword="null"/>.</exception>
-    public OpenAIResponseChatClient(OpenAIResponseClient responseClient)
+    public OpenAIResponsesChatClient(OpenAIResponseClient responseClient)
     {
         _ = Throw.IfNull(responseClient);
 
@@ -78,10 +78,16 @@ public async Task<ChatResponse> GetResponseAsync(
         // Make the call to the OpenAIResponseClient.
         var openAIResponse = (await _responseClient.CreateResponseAsync(openAIResponseItems, openAIOptions, cancellationToken).ConfigureAwait(false)).Value;
 
+        // Convert the response to a ChatResponse.
+        return FromOpenAIResponse(openAIResponse, openAIOptions);
+    }
+
+    internal static ChatResponse FromOpenAIResponse(OpenAIResponse openAIResponse, ResponseCreationOptions? openAIOptions)
+    {
         // Convert and return the results.
         ChatResponse response = new()
         {
-            ConversationId = openAIOptions.StoredOutputEnabled is false ? null : openAIResponse.Id,
+            ConversationId = openAIOptions?.StoredOutputEnabled is false ? null : openAIResponse.Id,
             CreatedAt = openAIResponse.CreatedAt,
             FinishReason = ToFinishReason(openAIResponse.IncompleteStatusDetails?.Reason),
             Messages = [new(ChatRole.Assistant, [])],
diff --git a/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIAssistantChatClientTests.cs b/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIAssistantChatClientTests.cs
index 3b084b5ec8a..7779e4cf18d 100644
--- a/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIAssistantChatClientTests.cs
+++ b/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIAssistantChatClientTests.cs
@@ -19,7 +19,8 @@ public class OpenAIAssistantChatClientTests
     public void AsIChatClient_InvalidArgs_Throws()
     {
         Assert.Throws<ArgumentNullException>("assistantClient", () => ((AssistantClient)null!).AsIChatClient("assistantId"));
-        Assert.Throws<ArgumentNullException>("assistantId", () => new AssistantClient("ignored").AsIChatClient(null!));
+        Assert.Throws<ArgumentNullException>("assistantId", () => new AssistantClient("ignored").AsIChatClient((string)null!));
+        Assert.Throws<ArgumentNullException>("assistant", () => new AssistantClient("ignored").AsIChatClient((Assistant)null!));
     }
 
     [Fact]
diff --git a/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIChatClientTests.cs b/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIChatClientTests.cs
index d06d8f520be..640dab54f8e 100644
--- a/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIChatClientTests.cs
+++ b/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIChatClientTests.cs
@@ -398,7 +398,7 @@ public async Task ChatOptions_DoNotOverwrite_NotNullPropertiesInRawRepresentatio
                     ResponseFormat = OpenAI.Chat.ChatResponseFormat.CreateTextFormat()
                 };
                 openAIOptions.StopSequences.Add("hello");
-                openAIOptions.Tools.Add(OpenAIClientExtensions.AsOpenAIChatTool(tool));
+                openAIOptions.Tools.Add(tool.AsOpenAIChatTool());
                 return openAIOptions;
             },
             ModelId = null,
@@ -475,7 +475,7 @@ public async Task ChatOptions_DoNotOverwrite_NotNullPropertiesInRawRepresentatio
                     ResponseFormat = OpenAI.Chat.ChatResponseFormat.CreateTextFormat()
                 };
                 openAIOptions.StopSequences.Add("hello");
-                openAIOptions.Tools.Add(OpenAIClientExtensions.AsOpenAIChatTool(tool));
+                openAIOptions.Tools.Add(tool.AsOpenAIChatTool());
                 return openAIOptions;
             },
             ModelId = null, // has no effect, you cannot change the model of an OpenAI's ChatClient.
diff --git a/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIConversionTests.cs b/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIConversionTests.cs
index 951554eda75..73f3ae65548 100644
--- a/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIConversionTests.cs
+++ b/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIConversionTests.cs
@@ -183,4 +183,37 @@ public void AsOpenAIResponseItems_ProducesExpectedOutput()
         Assert.Equal(OpenAI.Responses.MessageRole.Assistant, m5.Role);
         Assert.Equal("The answer is 42.", Assert.Single(m5.Content).Text);
     }
+
+    [Fact]
+    public void AsChatResponse_ConvertsOpenAIChatCompletion()
+    {
+        Assert.Throws<ArgumentNullException>("chatCompletion", () => ((ChatCompletion)null!).AsChatResponse());
+
+        ChatCompletion cc = OpenAIChatModelFactory.ChatCompletion(
+            "id", OpenAI.Chat.ChatFinishReason.Length, null, null,
+            [ChatToolCall.CreateFunctionToolCall("id", "functionName", BinaryData.FromString("test"))],
+            ChatMessageRole.User, null, null, null, new DateTimeOffset(2025, 1, 1, 0, 0, 0, TimeSpan.Zero),
+            "model123", null, OpenAIChatModelFactory.ChatTokenUsage(2, 1, 3));
+        cc.Content.Add(ChatMessageContentPart.CreateTextPart("Hello, world!"));
+        cc.Content.Add(ChatMessageContentPart.CreateImagePart(new Uri("http://example.com/image.png")));
+
+        ChatResponse response = cc.AsChatResponse();
+
+        Assert.Equal("id", response.ResponseId);
+        Assert.Equal(ChatFinishReason.Length, response.FinishReason);
+        Assert.Equal("model123", response.ModelId);
+        Assert.Equal(new DateTimeOffset(2025, 1, 1, 0, 0, 0, TimeSpan.Zero), response.CreatedAt);
+        Assert.NotNull(response.Usage);
+        Assert.Equal(1, response.Usage.InputTokenCount);
+        Assert.Equal(2, response.Usage.OutputTokenCount);
+        Assert.Equal(3, response.Usage.TotalTokenCount);
+
+        ChatMessage message = Assert.Single(response.Messages);
+        Assert.Equal(ChatRole.User, message.Role);
+
+        Assert.Equal(3, message.Contents.Count);
+        Assert.Equal("Hello, world!", Assert.IsType<TextContent>(message.Contents[0]).Text);
+        Assert.Equal("http://example.com/image.png", Assert.IsType<UriContent>(message.Contents[1]).Uri.ToString());
+        Assert.Equal("functionName", Assert.IsType<FunctionCallContent>(message.Contents[2]).Name);
+    }
 }