diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/CHANGELOG.md b/src/Libraries/Microsoft.Extensions.AI.Abstractions/CHANGELOG.md
index 8e1b571967e..a586329aa33 100644
--- a/src/Libraries/Microsoft.Extensions.AI.Abstractions/CHANGELOG.md
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Microsoft.Extensions.AI.Abstractions Release History
 
+## 10.1.1 (NOT YET RELEASED)
+
+- Added `InputCachedTokenCount` and `ReasoningTokenCount` to `UsageDetails`.
+- Added constructors to `HostedCodeInterpreterTool`, `HostedFileSearchTool`, `HostedImageGeneratorTool`, `HostedMcpServerTool`,
+  and `HostedWebSearchTool` that accept a dictionary for `AdditionalProperties`.
+
 ## 10.1.0
 
 - Fixed package references for net10.0 asset.
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Microsoft.Extensions.AI.Abstractions.json b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Microsoft.Extensions.AI.Abstractions.json
index b0b47c4ef6a..e401502d82b 100644
--- a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Microsoft.Extensions.AI.Abstractions.json
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Microsoft.Extensions.AI.Abstractions.json
@@ -1918,9 +1918,17 @@
         {
           "Member": "Microsoft.Extensions.AI.HostedCodeInterpreterTool.HostedCodeInterpreterTool();",
           "Stage": "Stable"
+        },
+        {
+          "Member": "Microsoft.Extensions.AI.HostedCodeInterpreterTool.HostedCodeInterpreterTool(System.Collections.Generic.IReadOnlyDictionary<string, object?>? additionalProperties);",
+          "Stage": "Stable"
         }
       ],
       "Properties": [
+        {
+          "Member": "override System.Collections.Generic.IReadOnlyDictionary<string, object?> Microsoft.Extensions.AI.HostedCodeInterpreterTool.AdditionalProperties { get; }",
+          "Stage": "Stable"
+        },
         {
           "Member": "System.Collections.Generic.IList<Microsoft.Extensions.AI.AIContent>? Microsoft.Extensions.AI.HostedCodeInterpreterTool.Inputs { get; set; }",
           "Stage": "Stable"
@@ -1938,9 +1946,17 @@
         {
           "Member": "Microsoft.Extensions.AI.HostedFileSearchTool.HostedFileSearchTool();",
           "Stage": "Stable"
+        },
+        {
+          "Member": "Microsoft.Extensions.AI.HostedFileSearchTool.HostedFileSearchTool(System.Collections.Generic.IReadOnlyDictionary<string, object?>? additionalProperties);",
+          "Stage": "Stable"
         }
       ],
       "Properties": [
+        {
+          "Member": "override System.Collections.Generic.IReadOnlyDictionary<string, object?> Microsoft.Extensions.AI.HostedFileSearchTool.AdditionalProperties { get; }",
+          "Stage": "Stable"
+        },
         {
           "Member": "System.Collections.Generic.IList<Microsoft.Extensions.AI.AIContent>? Microsoft.Extensions.AI.HostedFileSearchTool.Inputs { get; set; }",
           "Stage": "Stable"
@@ -1962,9 +1978,17 @@
         {
           "Member": "Microsoft.Extensions.AI.HostedWebSearchTool.HostedWebSearchTool();",
           "Stage": "Stable"
+        },
+        {
+          "Member": "Microsoft.Extensions.AI.HostedWebSearchTool.HostedWebSearchTool(System.Collections.Generic.IReadOnlyDictionary<string, object?>? additionalProperties);",
+          "Stage": "Stable"
         }
       ],
       "Properties": [
+        {
+          "Member": "override System.Collections.Generic.IReadOnlyDictionary<string, object?> Microsoft.Extensions.AI.HostedWebSearchTool.AdditionalProperties { get; }",
+          "Stage": "Stable"
+        },
         {
           "Member": "override string Microsoft.Extensions.AI.HostedWebSearchTool.Name { get; }",
           "Stage": "Stable"
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedCodeInterpreterTool.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedCodeInterpreterTool.cs
index 4bd63a0df75..f0ab845a110 100644
--- a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedCodeInterpreterTool.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedCodeInterpreterTool.cs
@@ -12,14 +12,27 @@ namespace Microsoft.Extensions.AI;
 /// </remarks>
 public class HostedCodeInterpreterTool : AITool
 {
+    /// <summary>Any additional properties associated with the tool.</summary>
+    private IReadOnlyDictionary<string, object?>? _additionalProperties;
+
     /// <summary>Initializes a new instance of the <see cref="HostedCodeInterpreterTool"/> class.</summary>
     public HostedCodeInterpreterTool()
     {
     }
 
+    /// <summary>Initializes a new instance of the <see cref="HostedCodeInterpreterTool"/> class.</summary>
+    /// <param name="additionalProperties">Any additional properties associated with the tool.</param>
+    public HostedCodeInterpreterTool(IReadOnlyDictionary<string, object?>? additionalProperties)
+    {
+        _additionalProperties = additionalProperties;
+    }
+
     /// <inheritdoc />
     public override string Name => "code_interpreter";
 
+    /// <inheritdoc />
+    public override IReadOnlyDictionary<string, object?> AdditionalProperties => _additionalProperties ?? base.AdditionalProperties;
+
     /// <summary>Gets or sets a collection of <see cref="AIContent"/> to be used as input to the code interpreter tool.</summary>
     /// <remarks>
     /// Services support different varied kinds of inputs. Most support the IDs of files that are hosted by the service,
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedFileSearchTool.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedFileSearchTool.cs
index b130e26b647..3456c301f17 100644
--- a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedFileSearchTool.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedFileSearchTool.cs
@@ -12,14 +12,27 @@ namespace Microsoft.Extensions.AI;
 /// </remarks>
 public class HostedFileSearchTool : AITool
 {
+    /// <summary>Any additional properties associated with the tool.</summary>
+    private IReadOnlyDictionary<string, object?>? _additionalProperties;
+
     /// <summary>Initializes a new instance of the <see cref="HostedFileSearchTool"/> class.</summary>
     public HostedFileSearchTool()
     {
     }
 
+    /// <summary>Initializes a new instance of the <see cref="HostedFileSearchTool"/> class.</summary>
+    /// <param name="additionalProperties">Any additional properties associated with the tool.</param>
+    public HostedFileSearchTool(IReadOnlyDictionary<string, object?>? additionalProperties)
+    {
+        _additionalProperties = additionalProperties;
+    }
+
     /// <inheritdoc />
     public override string Name => "file_search";
 
+    /// <inheritdoc />
+    public override IReadOnlyDictionary<string, object?> AdditionalProperties => _additionalProperties ?? base.AdditionalProperties;
+
     /// <summary>Gets or sets a collection of <see cref="AIContent"/> to be used as input to the file search tool.</summary>
     /// <remarks>
     /// If no explicit inputs are provided, the service determines what inputs should be searched. Different services
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedImageGenerationTool.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedImageGenerationTool.cs
index aca072653ab..4b75d2d5f08 100644
--- a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedImageGenerationTool.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedImageGenerationTool.cs
@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 
 namespace Microsoft.Extensions.AI;
@@ -13,6 +14,9 @@ namespace Microsoft.Extensions.AI;
 [Experimental("MEAI001")]
 public class HostedImageGenerationTool : AITool
 {
+    /// <summary>Any additional properties associated with the tool.</summary>
+    private IReadOnlyDictionary<string, object?>? _additionalProperties;
+
     /// <summary>
     /// Initializes a new instance of the <see cref="HostedImageGenerationTool"/> class with the specified options.
     /// </summary>
@@ -20,6 +24,19 @@ public HostedImageGenerationTool()
     {
     }
 
+    /// <summary>Initializes a new instance of the <see cref="HostedImageGenerationTool"/> class.</summary>
+    /// <param name="additionalProperties">Any additional properties associated with the tool.</param>
+    public HostedImageGenerationTool(IReadOnlyDictionary<string, object?>? additionalProperties)
+    {
+        _additionalProperties = additionalProperties;
+    }
+
+    /// <inheritdoc />
+    public override string Name => "image_generation";
+
+    /// <inheritdoc />
+    public override IReadOnlyDictionary<string, object?> AdditionalProperties => _additionalProperties ?? base.AdditionalProperties;
+
     /// <summary>
     /// Gets or sets the options used to configure image generation.
     /// </summary>
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedMcpServerTool.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedMcpServerTool.cs
index aa33a581710..fbc80fe4d59 100644
--- a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedMcpServerTool.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedMcpServerTool.cs
@@ -14,6 +14,9 @@ namespace Microsoft.Extensions.AI;
 [Experimental("MEAI001")]
 public class HostedMcpServerTool : AITool
 {
+    /// <summary>Any additional properties associated with the tool.</summary>
+    private IReadOnlyDictionary<string, object?>? _additionalProperties;
+
     /// <summary>
     /// Initializes a new instance of the <see cref="HostedMcpServerTool"/> class.
     /// </summary>
@@ -27,6 +30,20 @@ public HostedMcpServerTool(string serverName, string serverAddress)
         ServerAddress = Throw.IfNullOrWhitespace(serverAddress);
     }
 
+    /// <summary>
+    /// Initializes a new instance of the <see cref="HostedMcpServerTool"/> class.
+    /// </summary>
+    /// <param name="serverName">The name of the remote MCP server.</param>
+    /// <param name="serverAddress">The address of the remote MCP server. This may be a URL, or in the case of a service providing built-in MCP servers with known names, it can be such a name.</param>
+    /// <param name="additionalProperties">Any additional properties associated with the tool.</param>
+    /// <exception cref="ArgumentNullException"><paramref name="serverName"/> or <paramref name="serverAddress"/> is <see langword="null"/>.</exception>
+    /// <exception cref="ArgumentException"><paramref name="serverName"/> or <paramref name="serverAddress"/> is empty or composed entirely of whitespace.</exception>
+    public HostedMcpServerTool(string serverName, string serverAddress, IReadOnlyDictionary<string, object?>? additionalProperties)
+        : this(serverName, serverAddress)
+    {
+        _additionalProperties = additionalProperties;
+    }
+
     /// <summary>
     /// Initializes a new instance of the <see cref="HostedMcpServerTool"/> class.
     /// </summary>
@@ -40,6 +57,21 @@ public HostedMcpServerTool(string serverName, Uri serverUrl)
     {
     }
 
+    /// <summary>
+    /// Initializes a new instance of the <see cref="HostedMcpServerTool"/> class.
+    /// </summary>
+    /// <param name="serverName">The name of the remote MCP server.</param>
+    /// <param name="serverUrl">The URL of the remote MCP server.</param>
+    /// <param name="additionalProperties">Any additional properties associated with the tool.</param>
+    /// <exception cref="ArgumentNullException"><paramref name="serverName"/> or <paramref name="serverUrl"/> is <see langword="null"/>.</exception>
+    /// <exception cref="ArgumentException"><paramref name="serverName"/> is empty or composed entirely of whitespace.</exception>
+    /// <exception cref="ArgumentException"><paramref name="serverUrl"/> is not an absolute URL.</exception>
+    public HostedMcpServerTool(string serverName, Uri serverUrl, IReadOnlyDictionary<string, object?>? additionalProperties)
+        : this(serverName, ValidateUrl(serverUrl))
+    {
+        _additionalProperties = additionalProperties;
+    }
+
     private static string ValidateUrl(Uri serverUrl)
     {
         _ = Throw.IfNull(serverUrl);
@@ -55,6 +87,9 @@ private static string ValidateUrl(Uri serverUrl)
     /// <inheritdoc />
     public override string Name => "mcp";
 
+    /// <inheritdoc />
+    public override IReadOnlyDictionary<string, object?> AdditionalProperties => _additionalProperties ?? base.AdditionalProperties;
+
     /// <summary>
     /// Gets the name of the remote MCP server that is used to identify it.
     /// </summary>
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedWebSearchTool.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedWebSearchTool.cs
index 19d25510d19..c107473eb49 100644
--- a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedWebSearchTool.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedWebSearchTool.cs
@@ -1,6 +1,8 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Collections.Generic;
+
 namespace Microsoft.Extensions.AI;
 
 /// <summary>Represents a hosted tool that can be specified to an AI service to enable it to perform web searches.</summary>
@@ -10,11 +12,24 @@ namespace Microsoft.Extensions.AI;
 /// </remarks>
 public class HostedWebSearchTool : AITool
 {
+    /// <summary>Any additional properties associated with the tool.</summary>
+    private IReadOnlyDictionary<string, object?>? _additionalProperties;
+
     /// <summary>Initializes a new instance of the <see cref="HostedWebSearchTool"/> class.</summary>
     public HostedWebSearchTool()
     {
     }
 
+    /// <summary>Initializes a new instance of the <see cref="HostedWebSearchTool"/> class.</summary>
+    /// <param name="additionalProperties">Any additional properties associated with the tool.</param>
+    public HostedWebSearchTool(IReadOnlyDictionary<string, object?>? additionalProperties)
+    {
+        _additionalProperties = additionalProperties;
+    }
+
     /// <inheritdoc />
     public override string Name => "web_search";
+
+    /// <inheritdoc />
+    public override IReadOnlyDictionary<string, object?> AdditionalProperties => _additionalProperties ?? base.AdditionalProperties;
 }
diff --git a/src/Libraries/Microsoft.Extensions.AI.OpenAI/CHANGELOG.md b/src/Libraries/Microsoft.Extensions.AI.OpenAI/CHANGELOG.md
index 607fe6228d6..6e087263cca 100644
--- a/src/Libraries/Microsoft.Extensions.AI.OpenAI/CHANGELOG.md
+++ b/src/Libraries/Microsoft.Extensions.AI.OpenAI/CHANGELOG.md
@@ -1,5 +1,12 @@
 # Microsoft.Extensions.AI.OpenAI Release History
 
+## 10.1.1-preview.1.? (NOT YET RELEASED)
+
+- Updated to accommodate the additions in `Microsoft.Extensions.AI.Abstractions`.
+- Updated the OpenAI Responses and Chat Completion `IChatClient`s to populate `UsageDetails`'s `InputCachedTokenCount` and `ReasoningTokenCount`.
+- Updated handling of `HostedWebSearchTool`, `HostedFileSearchTool`, and `HostedImageGenerationTool` to pull OpenAI-specific
+  options from `AdditionalProperties`.
+
 ## 10.1.0-preview.1.25608.1
 
 - Fixed package references for net10.0 asset.
diff --git a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIAssistantsChatClient.cs b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIAssistantsChatClient.cs
index 065ad80d23a..96f3d9113c2 100644
--- a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIAssistantsChatClient.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIAssistantsChatClient.cs
@@ -409,7 +409,10 @@ internal static FunctionToolDefinition ToOpenAIAssistantsFunctionToolDefinition(
                             break;
 
                         case HostedFileSearchTool fileSearchTool:
-                            _ = toolsOverride.Add(ToolDefinition.CreateFileSearch(fileSearchTool.MaximumResultCount));
+                            var fst = ToolDefinition.CreateFileSearch(fileSearchTool.MaximumResultCount);
+                            fst.RankingOptions = fileSearchTool.GetProperty<FileSearchRankingOptions>(nameof(FileSearchToolDefinition.RankingOptions));
+                            _ = toolsOverride.Add(fst);
+
                             if (fileSearchTool.Inputs is { Count: > 0 } fileSearchInputs)
                             {
                                 foreach (var input in fileSearchInputs)
diff --git a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIClientExtensions.cs b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIClientExtensions.cs
index 285b2c1e7ae..f696e394b44 100644
--- a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIClientExtensions.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIClientExtensions.cs
@@ -242,6 +242,10 @@ internal static void PatchModelIfNotSet(ref JsonPatch patch, string? modelId)
         }
     }
 
+    /// <summary>Gets the typed property of the specified name from the tool's <see cref="AITool.AdditionalProperties"/>.</summary>
+    internal static T? GetProperty<T>(this AITool tool, string name) =>
+        tool.AdditionalProperties?.TryGetValue(name, out object? value) is true && value is T tValue ? tValue : default;
+
     /// <summary>Used to create the JSON payload for an OpenAI tool description.</summary>
     internal sealed class ToolJson
     {
diff --git a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponsesChatClient.cs b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponsesChatClient.cs
index 1c172db283a..98c30b73526 100644
--- a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponsesChatClient.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponsesChatClient.cs
@@ -544,25 +544,17 @@ void IDisposable.Dispose()
                 return ToResponseTool(aiFunction, options);
 
             case HostedWebSearchTool webSearchTool:
-                WebSearchToolLocation? location = null;
-                if (webSearchTool.AdditionalProperties.TryGetValue(nameof(WebSearchToolLocation), out object? objLocation))
-                {
-                    location = objLocation as WebSearchToolLocation;
-                }
-
-                WebSearchToolContextSize? size = null;
-                if (webSearchTool.AdditionalProperties.TryGetValue(nameof(WebSearchToolContextSize), out object? objSize) &&
-                    objSize is WebSearchToolContextSize)
-                {
-                    size = (WebSearchToolContextSize)objSize;
-                }
-
-                return ResponseTool.CreateWebSearchTool(location, size);
+                return ResponseTool.CreateWebSearchTool(
+                    webSearchTool.GetProperty<WebSearchToolLocation?>(nameof(WebSearchTool.UserLocation)),
+                    webSearchTool.GetProperty<WebSearchToolContextSize?>(nameof(WebSearchTool.SearchContextSize)),
+                    webSearchTool.GetProperty<WebSearchToolFilters?>(nameof(WebSearchTool.Filters)));
 
             case HostedFileSearchTool fileSearchTool:
                 return ResponseTool.CreateFileSearchTool(
                     fileSearchTool.Inputs?.OfType<HostedVectorStoreContent>().Select(c => c.VectorStoreId) ?? [],
-                    fileSearchTool.MaximumResultCount);
+                    fileSearchTool.MaximumResultCount,
+                    fileSearchTool.GetProperty<FileSearchToolRankingOptions?>(nameof(FileSearchTool.RankingOptions)),
+                    fileSearchTool.GetProperty<BinaryData?>(nameof(FileSearchTool.Filters)));
 
             case HostedImageGenerationTool imageGenerationTool:
                 return ToImageResponseTool(imageGenerationTool);
@@ -642,36 +634,31 @@ internal static FunctionTool ToResponseTool(AIFunctionDeclaration aiFunction, Ch
 
     internal static ImageGenerationTool ToImageResponseTool(HostedImageGenerationTool imageGenerationTool)
     {
-        ImageGenerationTool result = new();
-        ImageGenerationOptions? imageGenerationOptions = imageGenerationTool.Options;
-
-        // Model: Image generation model
-        result.Model = imageGenerationOptions?.ModelId;
-
-        // Size: Image dimensions (e.g., 1024x1024, 1024x1536)
-        if (imageGenerationOptions?.ImageSize is not null)
-        {
-            result.Size = new ImageGenerationToolSize(
-                imageGenerationOptions.ImageSize.Value.Width,
-                imageGenerationOptions.ImageSize.Value.Height);
-        }
+        ImageGenerationOptions? options = imageGenerationTool.Options;
 
-        // OutputFileFormat: File output format
-        if (imageGenerationOptions?.MediaType is not null)
+        return new()
         {
-            result.OutputFileFormat = imageGenerationOptions.MediaType switch
-            {
-                "image/png" => ImageGenerationToolOutputFileFormat.Png,
-                "image/jpeg" => ImageGenerationToolOutputFileFormat.Jpeg,
-                "image/webp" => ImageGenerationToolOutputFileFormat.Webp,
-                _ => null,
-            };
-        }
-
-        // PartialImageCount: Whether to return partial images during generation
-        result.PartialImageCount ??= imageGenerationOptions?.StreamingCount;
-
-        return result;
+            Background = imageGenerationTool.GetProperty<ImageGenerationToolBackground?>(nameof(ImageGenerationTool.Background)),
+            InputFidelity = imageGenerationTool.GetProperty<ImageGenerationToolInputFidelity?>(nameof(ImageGenerationTool.InputFidelity)),
+            InputImageMask = imageGenerationTool.GetProperty<ImageGenerationToolInputImageMask?>(nameof(ImageGenerationTool.InputImageMask)),
+            Model = options?.ModelId,
+            ModerationLevel = imageGenerationTool.GetProperty<ImageGenerationToolModerationLevel?>(nameof(ImageGenerationTool.ModerationLevel)),
+            OutputCompressionFactor = imageGenerationTool.GetProperty<int?>(nameof(ImageGenerationTool.OutputCompressionFactor)),
+            OutputFileFormat = options?.MediaType is not null ?
+                options.MediaType switch
+                {
+                    "image/png" => ImageGenerationToolOutputFileFormat.Png,
+                    "image/jpeg" => ImageGenerationToolOutputFileFormat.Jpeg,
+                    "image/webp" => ImageGenerationToolOutputFileFormat.Webp,
+                    _ => null,
+                } :
+                null,
+            PartialImageCount = options?.StreamingCount,
+            Quality = imageGenerationTool.GetProperty<ImageGenerationToolQuality?>(nameof(ImageGenerationTool.Quality)),
+            Size = options?.ImageSize is not null ?
+                new ImageGenerationToolSize(options.ImageSize.Value.Width, options.ImageSize.Value.Height) :
+                null
+        };
     }
 
     /// <summary>Creates a <see cref="ChatRole"/> from a <see cref="MessageRole"/>.</summary>
diff --git a/src/Libraries/Microsoft.Extensions.AI/CHANGELOG.md b/src/Libraries/Microsoft.Extensions.AI/CHANGELOG.md
index 4f06605b47f..816e8b92267 100644
--- a/src/Libraries/Microsoft.Extensions.AI/CHANGELOG.md
+++ b/src/Libraries/Microsoft.Extensions.AI/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Microsoft.Extensions.AI Release History
 
+## 10.1.1 (NOT YET RELEASED)
+
+- Updated to accommodate the additions in `Microsoft.Extensions.AI.Abstractions`.
+
 ## 10.1.0
 
 - Fixed package references for net10.0 asset.
diff --git a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedCodeInterpreterToolTests.cs b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedCodeInterpreterToolTests.cs
index 19044a6a295..34f6dd32f1e 100644
--- a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedCodeInterpreterToolTests.cs
+++ b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedCodeInterpreterToolTests.cs
@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Collections.Generic;
 using Xunit;
 
 namespace Microsoft.Extensions.AI;
@@ -18,6 +19,24 @@ public void Constructor_Roundtrips()
         Assert.Equal(tool.Name, tool.ToString());
     }
 
+    [Fact]
+    public void Constructor_AdditionalProperties_Roundtrips()
+    {
+        var props = new Dictionary<string, object?> { ["key"] = "value" };
+        var tool = new HostedCodeInterpreterTool(props);
+
+        Assert.Equal("code_interpreter", tool.Name);
+        Assert.Same(props, tool.AdditionalProperties);
+    }
+
+    [Fact]
+    public void Constructor_NullAdditionalProperties_UsesEmpty()
+    {
+        var tool = new HostedCodeInterpreterTool(null);
+
+        Assert.Empty(tool.AdditionalProperties);
+    }
+
     [Fact]
     public void Properties_Roundtrip()
     {
diff --git a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedFileSearchToolTests.cs b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedFileSearchToolTests.cs
index e2d71a65013..cffa5b418b1 100644
--- a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedFileSearchToolTests.cs
+++ b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedFileSearchToolTests.cs
@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Collections.Generic;
 using Xunit;
 
 namespace Microsoft.Extensions.AI;
@@ -19,6 +20,24 @@ public void Constructor_Roundtrips()
         Assert.Equal(tool.Name, tool.ToString());
     }
 
+    [Fact]
+    public void Constructor_AdditionalProperties_Roundtrips()
+    {
+        var props = new Dictionary<string, object?> { ["key"] = "value" };
+        var tool = new HostedFileSearchTool(props);
+
+        Assert.Equal("file_search", tool.Name);
+        Assert.Same(props, tool.AdditionalProperties);
+    }
+
+    [Fact]
+    public void Constructor_NullAdditionalProperties_UsesEmpty()
+    {
+        var tool = new HostedFileSearchTool(null);
+
+        Assert.Empty(tool.AdditionalProperties);
+    }
+
     [Fact]
     public void Properties_Roundtrip()
     {
diff --git a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedImageGenerationToolTests.cs b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedImageGenerationToolTests.cs
new file mode 100644
index 00000000000..1f14ca7175d
--- /dev/null
+++ b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedImageGenerationToolTests.cs
@@ -0,0 +1,51 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Collections.Generic;
+using Xunit;
+
+namespace Microsoft.Extensions.AI;
+
+public class HostedImageGenerationToolTests
+{
+    [Fact]
+    public void Constructor_Roundtrips()
+    {
+        var tool = new HostedImageGenerationTool();
+        Assert.Equal("image_generation", tool.Name);
+        Assert.Empty(tool.Description);
+        Assert.Empty(tool.AdditionalProperties);
+        Assert.Null(tool.Options);
+        Assert.Equal(tool.Name, tool.ToString());
+    }
+
+    [Fact]
+    public void Constructor_AdditionalProperties_Roundtrips()
+    {
+        var props = new Dictionary<string, object?> { ["key"] = "value" };
+        var tool = new HostedImageGenerationTool(props);
+
+        Assert.Equal("image_generation", tool.Name);
+        Assert.Same(props, tool.AdditionalProperties);
+    }
+
+    [Fact]
+    public void Constructor_NullAdditionalProperties_UsesEmpty()
+    {
+        var tool = new HostedImageGenerationTool(null);
+
+        Assert.Empty(tool.AdditionalProperties);
+    }
+
+    [Fact]
+    public void Options_Roundtrip()
+    {
+        var options = new ImageGenerationOptions();
+        var tool = new HostedImageGenerationTool
+        {
+            Options = options
+        };
+
+        Assert.Same(options, tool.Options);
+    }
+}
diff --git a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedMcpServerToolTests.cs b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedMcpServerToolTests.cs
index ec1dc407973..aa23cfd3ff4 100644
--- a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedMcpServerToolTests.cs
+++ b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedMcpServerToolTests.cs
@@ -26,6 +26,36 @@ public void Constructor_PropsDefault()
         Assert.Null(tool.ApprovalMode);
     }
 
+    [Fact]
+    public void Constructor_AdditionalProperties_String_Roundtrips()
+    {
+        var props = new Dictionary<string, object?> { ["key"] = "value" };
+        HostedMcpServerTool tool = new("serverName", "connector_id", props);
+
+        Assert.Equal("serverName", tool.ServerName);
+        Assert.Equal("connector_id", tool.ServerAddress);
+        Assert.Same(props, tool.AdditionalProperties);
+    }
+
+    [Fact]
+    public void Constructor_AdditionalProperties_Uri_Roundtrips()
+    {
+        var props = new Dictionary<string, object?> { ["key"] = "value" };
+        HostedMcpServerTool tool = new("serverName", new Uri("https://localhost/"), props);
+
+        Assert.Equal("serverName", tool.ServerName);
+        Assert.Equal("https://localhost/", tool.ServerAddress);
+        Assert.Same(props, tool.AdditionalProperties);
+    }
+
+    [Fact]
+    public void Constructor_NullAdditionalProperties_UsesEmpty()
+    {
+        HostedMcpServerTool tool = new("serverName", "connector_id", null);
+
+        Assert.Empty(tool.AdditionalProperties);
+    }
+
     [Fact]
     public void Constructor_Roundtrips()
     {
diff --git a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedWebSearchToolTests.cs b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedWebSearchToolTests.cs
index 4bb6ca4b847..7040289a210 100644
--- a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedWebSearchToolTests.cs
+++ b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedWebSearchToolTests.cs
@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Collections.Generic;
 using Xunit;
 
 namespace Microsoft.Extensions.AI;
@@ -16,4 +17,22 @@ public void Constructor_Roundtrips()
         Assert.Empty(tool.AdditionalProperties);
         Assert.Equal(tool.Name, tool.ToString());
     }
+
+    [Fact]
+    public void Constructor_AdditionalProperties_Roundtrips()
+    {
+        var props = new Dictionary<string, object?> { ["key"] = "value" };
+        var tool = new HostedWebSearchTool(props);
+
+        Assert.Equal("web_search", tool.Name);
+        Assert.Same(props, tool.AdditionalProperties);
+    }
+
+    [Fact]
+    public void Constructor_NullAdditionalProperties_UsesEmpty()
+    {
+        var tool = new HostedWebSearchTool(null);
+
+        Assert.Empty(tool.AdditionalProperties);
+    }
 }
diff --git a/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIConversionTests.cs b/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIConversionTests.cs
index 9c4ffeefdcd..0ab4ea2c6b1 100644
--- a/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIConversionTests.cs
+++ b/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIConversionTests.cs
@@ -141,8 +141,8 @@ public void AsOpenAIResponseTool_WithHostedWebSearchToolWithAdditionalProperties
         var location = WebSearchToolLocation.CreateApproximateLocation("US", "Region", "City", "UTC");
         var webSearchTool = new HostedWebSearchToolWithProperties(new Dictionary<string, object?>
         {
-            [nameof(WebSearchToolLocation)] = location,
-            [nameof(WebSearchToolContextSize)] = WebSearchToolContextSize.High
+            [nameof(WebSearchTool.UserLocation)] = location,
+            [nameof(WebSearchTool.SearchContextSize)] = WebSearchToolContextSize.High
         });
 
         var result = webSearchTool.AsOpenAIResponseTool();
@@ -205,6 +205,30 @@ public void AsOpenAIResponseTool_WithHostedFileSearchToolWithMaxResults_Produces
         Assert.Equal(10, tool.MaxResultCount);
     }
 
+    [Fact]
+    public void AsOpenAIResponseTool_WithHostedFileSearchToolWithAdditionalProperties_ProducesValidFileSearchTool()
+    {
+        var rankingOptions = new FileSearchToolRankingOptions { ScoreThreshold = 0.5f };
+        var filters = BinaryData.FromString("{\"type\":\"eq\",\"key\":\"status\",\"value\":\"published\"}");
+        var fileSearchTool = new HostedFileSearchTool(new Dictionary<string, object?>
+        {
+            [nameof(FileSearchTool.RankingOptions)] = rankingOptions,
+            [nameof(FileSearchTool.Filters)] = filters
+        })
+        {
+            MaximumResultCount = 15
+        };
+
+        var result = fileSearchTool.AsOpenAIResponseTool();
+
+        Assert.NotNull(result);
+        var tool = Assert.IsType<FileSearchTool>(result);
+        Assert.NotNull(tool.RankingOptions);
+        Assert.Equal(0.5f, tool.RankingOptions.ScoreThreshold);
+        Assert.NotNull(tool.Filters);
+        Assert.Equal(15, tool.MaxResultCount);
+    }
+
     [Fact]
     public void AsOpenAIResponseTool_WithHostedCodeInterpreterTool_ProducesValidCodeInterpreterTool()
     {
@@ -236,6 +260,99 @@ public void AsOpenAIResponseTool_WithHostedCodeInterpreterToolWithFiles_Produces
         Assert.Equal(fileContent.FileId, autoContainerConfig.FileIds[0]);
     }
 
+    [Fact]
+    public void AsOpenAIResponseTool_WithHostedImageGenerationTool_ProducesValidImageGenerationTool()
+    {
+        var imageGenTool = new HostedImageGenerationTool
+        {
+            Options = new ImageGenerationOptions { MediaType = "image/png" }
+        };
+
+        var result = imageGenTool.AsOpenAIResponseTool();
+
+        Assert.NotNull(result);
+        var tool = Assert.IsType<ImageGenerationTool>(result);
+        Assert.NotNull(tool);
+    }
+
+    [Fact]
+    public void AsOpenAIResponseTool_WithHostedImageGenerationToolWithOptions_ProducesValidImageGenerationTool()
+    {
+        var imageGenTool = new HostedImageGenerationTool
+        {
+            Options = new ImageGenerationOptions
+            {
+                ModelId = "gpt-image-1",
+                MediaType = "image/png",
+                ImageSize = new System.Drawing.Size(1024, 1024),
+                StreamingCount = 2
+            }
+        };
+
+        var result = imageGenTool.AsOpenAIResponseTool();
+
+        Assert.NotNull(result);
+        var tool = Assert.IsType<ImageGenerationTool>(result);
+        Assert.Equal("gpt-image-1", tool.Model);
+        Assert.Equal(ImageGenerationToolOutputFileFormat.Png, tool.OutputFileFormat);
+        Assert.NotNull(tool.Size);
+        Assert.Equal(2, tool.PartialImageCount);
+    }
+
+    [Fact]
+    public void AsOpenAIResponseTool_WithHostedImageGenerationToolWithAdditionalProperties_ProducesValidImageGenerationTool()
+    {
+        var imageGenTool = new HostedImageGenerationTool(new Dictionary<string, object?>
+        {
+            [nameof(ImageGenerationTool.Background)] = ImageGenerationToolBackground.Transparent,
+            [nameof(ImageGenerationTool.InputFidelity)] = ImageGenerationToolInputFidelity.High,
+            [nameof(ImageGenerationTool.ModerationLevel)] = ImageGenerationToolModerationLevel.Low,
+            [nameof(ImageGenerationTool.OutputCompressionFactor)] = 50,
+            [nameof(ImageGenerationTool.Quality)] = ImageGenerationToolQuality.High
+        })
+        {
+            Options = new ImageGenerationOptions
+            {
+                ModelId = "gpt-image-1",
+                MediaType = "image/jpeg",
+            }
+        };
+
+        var result = imageGenTool.AsOpenAIResponseTool();
+
+        Assert.NotNull(result);
+        var tool = Assert.IsType<ImageGenerationTool>(result);
+        Assert.Equal("gpt-image-1", tool.Model);
+        Assert.Equal(ImageGenerationToolOutputFileFormat.Jpeg, tool.OutputFileFormat);
+        Assert.Equal(ImageGenerationToolBackground.Transparent, tool.Background);
+        Assert.Equal(ImageGenerationToolInputFidelity.High, tool.InputFidelity);
+        Assert.Equal(ImageGenerationToolModerationLevel.Low, tool.ModerationLevel);
+        Assert.Equal(50, tool.OutputCompressionFactor);
+        Assert.Equal(ImageGenerationToolQuality.High, tool.Quality);
+    }
+
+    [Fact]
+    public void AsOpenAIResponseTool_WithHostedImageGenerationToolWithInputImageMask_ProducesValidImageGenerationTool()
+    {
+        var inputImageMask = new ImageGenerationToolInputImageMask(
+            BinaryData.FromBytes([0x89, 0x50, 0x4E, 0x47]),
+            "image/png");
+
+        var imageGenTool = new HostedImageGenerationTool(new Dictionary<string, object?>
+        {
+            [nameof(ImageGenerationTool.InputImageMask)] = inputImageMask
+        })
+        {
+            Options = new ImageGenerationOptions { MediaType = "image/png" }
+        };
+
+        var result = imageGenTool.AsOpenAIResponseTool();
+
+        Assert.NotNull(result);
+        var tool = Assert.IsType<ImageGenerationTool>(result);
+        Assert.NotNull(tool.InputImageMask);
+    }
+
     [Fact]
     public void AsOpenAIResponseTool_WithHostedMcpServerTool_ProducesValidMcpTool()
     {