From 48be40c018f55cc197598bb008bce99a969b31e8 Mon Sep 17 00:00:00 2001
From: Jose Perez Rodriguez <joperezr@microsoft.com>
Date: Wed, 3 Sep 2025 23:43:33 +0000
Subject: [PATCH 1/8] Merged PR 52950: Getting ready for 9.9 release

Getting ready for 9.9 release

----
#### AI description  (iteration 1)
#### PR Classification
This pull request updates dependency versions and build configurations in preparation for the 9.9 release.

#### PR Summary
The changes bump most dependency and LTS versions from 9.0.8 to 9.0.9 (and 8.0.19 to 8.0.20), and adjust build settings for a stable release. Key changes include:
- Updates in `eng/Version.Details.xml` and `eng/Versions.props` for dependency version bumps and setting `<StabilizePackageVersion>` to true and `<DotNetFinalVersionKind>` to release.
- Removal of the code coverage stage in `azure-pipelines.yml` and corresponding dependency in the pipeline orchestration.
- Modifications in `eng/pipelines/templates/BuildAndTest.yml` to add private feed credentials setup and comment out integration tests.
- Adjustments in `NuGet.config` to update package source configurations.
- Suppression of NU1507 warnings in `Directory.Build.props` due to internal feed usage.
<!-- GitOpsUserAgent=GitOps.Apps.Server.pullrequestcopilot -->
---
 Directory.Build.props                    |   5 +
 NuGet.config                             |  82 +++++++---
 azure-pipelines.yml                      |  46 ------
 eng/Version.Details.xml                  | 188 +++++++++++------------
 eng/Versions.props                       | 122 +++++++--------
 eng/pipelines/templates/BuildAndTest.yml |  32 +++-
 6 files changed, 245 insertions(+), 230 deletions(-)

diff --git a/Directory.Build.props b/Directory.Build.props
index 0af806af628..0c0fcf22bfd 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -34,6 +34,11 @@
     <TestNetCoreTargetFrameworks>$(NetCoreTargetFrameworks)</TestNetCoreTargetFrameworks>
   </PropertyGroup>
 
+  <!-- Internal branches don't use package source mapping feature due to internal feeds, so disable NU1507 warning saying it should be used. -->
+  <PropertyGroup>
+    <NoWarn>$(NoWarn);NU1507</NoWarn>
+  </PropertyGroup>
+
   <PropertyGroup>
     <CheckForOverflowUnderflow>false</CheckForOverflowUnderflow>
     <LangVersion>latest</LangVersion>
diff --git a/NuGet.config b/NuGet.config
index 0fedd015e82..a93d883fdb6 100644
--- a/NuGet.config
+++ b/NuGet.config
@@ -4,10 +4,40 @@
     <clear />
     <!--Begin: Package sources managed by Dependency Flow automation. Do not edit the sources below.-->
     <!--  Begin: Package sources from dotnet-aspnetcore -->
+    <add key="darc-int-dotnet-aspnetcore-c78f4a8" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-aspnetcore-c78f4a81/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-aspnetcore-c78f4a8-4" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-aspnetcore-c78f4a81-4/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-aspnetcore-c78f4a8-3" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-aspnetcore-c78f4a81-3/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-aspnetcore-c78f4a8-2" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-aspnetcore-c78f4a81-2/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-aspnetcore-c78f4a8-1" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-aspnetcore-c78f4a81-1/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-aspnetcore-ff66c26" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-aspnetcore-ff66c263/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-aspnetcore-ff66c26-4" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-aspnetcore-ff66c263-4/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-aspnetcore-ff66c26-3" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-aspnetcore-ff66c263-3/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-aspnetcore-ff66c26-2" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-aspnetcore-ff66c263-2/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-aspnetcore-ff66c26-1" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-aspnetcore-ff66c263-1/nuget/v3/index.json" />
     <!--  End: Package sources from dotnet-aspnetcore -->
     <!--  Begin: Package sources from dotnet-efcore -->
+    <add key="darc-int-dotnet-efcore-a947fe2" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-efcore-a947fe22/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-efcore-a947fe2-4" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-efcore-a947fe22-4/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-efcore-a947fe2-3" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-efcore-a947fe22-3/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-efcore-a947fe2-2" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-efcore-a947fe22-2/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-efcore-a947fe2-1" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-efcore-a947fe22-1/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-efcore-78871c8" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-efcore-78871c83/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-efcore-78871c8-4" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-efcore-78871c83-4/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-efcore-78871c8-3" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-efcore-78871c83-3/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-efcore-78871c8-2" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-efcore-78871c83-2/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-efcore-78871c8-1" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-efcore-78871c83-1/nuget/v3/index.json" />
     <!--  End: Package sources from dotnet-efcore -->
     <!--  Begin: Package sources from dotnet-runtime -->
+    <add key="darc-int-dotnet-runtime-574100b" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-runtime-574100b6/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-runtime-574100b-4" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-runtime-574100b6-4/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-runtime-574100b-3" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-runtime-574100b6-3/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-runtime-574100b-2" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-runtime-574100b6-2/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-runtime-574100b-1" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-runtime-574100b6-1/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-runtime-893c2eb" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-runtime-893c2ebb/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-runtime-893c2eb-4" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-runtime-893c2ebb-4/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-runtime-893c2eb-3" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-runtime-893c2ebb-3/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-runtime-893c2eb-2" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-runtime-893c2ebb-2/nuget/v3/index.json" />
+    <add key="darc-int-dotnet-runtime-893c2eb-1" value="https://pkgs.dev.azure.com/dnceng/internal/_packaging/darc-int-dotnet-runtime-893c2ebb-1/nuget/v3/index.json" />
     <!--  End: Package sources from dotnet-runtime -->
     <!--End: Package sources managed by Dependency Flow automation. Do not edit the sources above.-->
     <add key="dotnet-public" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-public/nuget/v3/index.json" />
@@ -18,35 +48,43 @@
     <!-- Used for the Rich Navigation indexing task -->
     <add key="richnav" value="https://pkgs.dev.azure.com/azure-public/vside/_packaging/vs-buildservices/nuget/v3/index.json" />
   </packageSources>
-  <!-- Define mappings by adding package patterns beneath the target source.
-       https://aka.ms/nuget-package-source-mapping  -->
-  <packageSourceMapping>
-    <packageSource key="dotnet-public">
-      <package pattern="*" />
-    </packageSource>
-    <packageSource key="dotnet-eng">
-      <package pattern="*" />
-    </packageSource>
-    <packageSource key="dotnet-tools">
-      <package pattern="*" />
-    </packageSource>
-    <packageSource key="dotnet9">
-      <package pattern="*" />
-    </packageSource>
-    <packageSource key="dotnet9-transport">
-      <package pattern="*" />
-    </packageSource>
-    <packageSource key="richnav">
-      <package pattern="*" />
-    </packageSource>
-  </packageSourceMapping>
   <disabledPackageSources>
     <!--Begin: Package sources managed by Dependency Flow automation. Do not edit the sources below.-->
     <!--  Begin: Package sources from dotnet-aspnetcore -->
+    <add key="darc-int-dotnet-aspnetcore-c78f4a8-1" value="true" />
+    <add key="darc-int-dotnet-aspnetcore-c78f4a8-2" value="true" />
+    <add key="darc-int-dotnet-aspnetcore-c78f4a8-3" value="true" />
+    <add key="darc-int-dotnet-aspnetcore-c78f4a8-4" value="true" />
+    <add key="darc-int-dotnet-aspnetcore-c78f4a8" value="true" />
+    <add key="darc-int-dotnet-aspnetcore-ff66c26-1" value="true" />
+    <add key="darc-int-dotnet-aspnetcore-ff66c26-2" value="true" />
+    <add key="darc-int-dotnet-aspnetcore-ff66c26-3" value="true" />
+    <add key="darc-int-dotnet-aspnetcore-ff66c26-4" value="true" />
+    <add key="darc-int-dotnet-aspnetcore-ff66c26" value="true" />
     <!--  Begin: Package sources from dotnet-efcore -->
+    <add key="darc-int-dotnet-efcore-a947fe2-1" value="true" />
+    <add key="darc-int-dotnet-efcore-a947fe2-2" value="true" />
+    <add key="darc-int-dotnet-efcore-a947fe2-3" value="true" />
+    <add key="darc-int-dotnet-efcore-a947fe2-4" value="true" />
+    <add key="darc-int-dotnet-efcore-a947fe2" value="true" />
+    <add key="darc-int-dotnet-efcore-78871c8-1" value="true" />
+    <add key="darc-int-dotnet-efcore-78871c8-2" value="true" />
+    <add key="darc-int-dotnet-efcore-78871c8-3" value="true" />
+    <add key="darc-int-dotnet-efcore-78871c8-4" value="true" />
+    <add key="darc-int-dotnet-efcore-78871c8" value="true" />
     <!--  End: Package sources from dotnet-efcore -->
     <!--  End: Package sources from dotnet-aspnetcore -->
     <!--  Begin: Package sources from dotnet-runtime -->
+    <add key="darc-int-dotnet-runtime-574100b-1" value="true" />
+    <add key="darc-int-dotnet-runtime-574100b-2" value="true" />
+    <add key="darc-int-dotnet-runtime-574100b-3" value="true" />
+    <add key="darc-int-dotnet-runtime-574100b-4" value="true" />
+    <add key="darc-int-dotnet-runtime-574100b" value="true" />
+    <add key="darc-int-dotnet-runtime-893c2eb-1" value="true" />
+    <add key="darc-int-dotnet-runtime-893c2eb-2" value="true" />
+    <add key="darc-int-dotnet-runtime-893c2eb-3" value="true" />
+    <add key="darc-int-dotnet-runtime-893c2eb-4" value="true" />
+    <add key="darc-int-dotnet-runtime-893c2eb" value="true" />
     <!--  End: Package sources from dotnet-runtime -->
     <!--End: Package sources managed by Dependency Flow automation. Do not edit the sources above.-->
   </disabledPackageSources>
diff --git a/azure-pipelines.yml b/azure-pipelines.yml
index 3ec5e3d1cdb..0052dc9f706 100644
--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -239,51 +239,6 @@ extends:
                 isWindows: false
                 warnAsError: 0
 
-    # ----------------------------------------------------------------
-    # This stage performs quality gates enforcements
-    # ----------------------------------------------------------------
-    - stage: codecoverage
-      displayName: CodeCoverage
-      dependsOn:
-      - build
-      condition: and(succeeded('build'), ne(variables['SkipQualityGates'], 'true'))
-      variables:
-      - template: /eng/common/templates-official/variables/pool-providers.yml@self
-      jobs:
-      - template: /eng/common/templates-official/jobs/jobs.yml@self
-        parameters:
-          enableMicrobuild: true
-          enableTelemetry: true
-          runAsPublic: ${{ variables['runAsPublic'] }}
-          workspace:
-            clean: all
-
-          # ----------------------------------------------------------------
-          # This stage downloads the code coverage reports from the build jobs,
-          # merges those and validates the combined test coverage.
-          # ----------------------------------------------------------------
-          jobs:
-          - job: CodeCoverageReport
-            timeoutInMinutes: 180
-
-            pool:
-              name: NetCore1ESPool-Internal
-              image: 1es-mariner-2
-              os: linux
-
-            preSteps:
-            - checkout: self
-              clean: true
-              persistCredentials: true
-              fetchDepth: 1
-
-            steps:
-            - script: $(Build.SourcesDirectory)/build.sh --ci --restore
-              displayName: Init toolset
-
-            - template: /eng/pipelines/templates/VerifyCoverageReport.yml
-
-
     # ----------------------------------------------------------------
     # This stage only performs a build treating warnings as errors
     # to detect any kind of code style violations
@@ -339,7 +294,6 @@ extends:
         parameters:
           validateDependsOn:
           - build
-          - codecoverage
           - correctness
           publishingInfraVersion: 3
           enableSymbolValidation: false
diff --git a/eng/Version.Details.xml b/eng/Version.Details.xml
index 3070e2658d3..b75b66eaea6 100644
--- a/eng/Version.Details.xml
+++ b/eng/Version.Details.xml
@@ -1,196 +1,196 @@
 <Dependencies>
   <ProductDependencies>
-    <Dependency Name="Microsoft.Bcl.AsyncInterfaces" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="Microsoft.Bcl.AsyncInterfaces" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Bcl.TimeProvider" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="Microsoft.Bcl.TimeProvider" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Extensions.Caching.Abstractions" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="Microsoft.Extensions.Caching.Abstractions" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Extensions.Caching.Memory" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="Microsoft.Extensions.Caching.Memory" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Extensions.Configuration.Abstractions" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="Microsoft.Extensions.Configuration.Abstractions" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Extensions.Configuration.Binder" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="Microsoft.Extensions.Configuration.Binder" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Extensions.Configuration.Json" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="Microsoft.Extensions.Configuration.Json" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Extensions.Configuration" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="Microsoft.Extensions.Configuration" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Extensions.DependencyInjection.Abstractions" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="Microsoft.Extensions.DependencyInjection.Abstractions" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Extensions.DependencyInjection" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="Microsoft.Extensions.DependencyInjection" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Extensions.Hosting.Abstractions" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="Microsoft.Extensions.Hosting.Abstractions" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Extensions.Diagnostics" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="Microsoft.Extensions.Diagnostics" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Extensions.Hosting" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="Microsoft.Extensions.Hosting" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Extensions.Http" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="Microsoft.Extensions.Http" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Extensions.Logging.Abstractions" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="Microsoft.Extensions.Logging.Abstractions" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Extensions.Logging.Configuration" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="Microsoft.Extensions.Logging.Configuration" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Extensions.Logging.Console" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="Microsoft.Extensions.Logging.Console" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Extensions.Logging" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="Microsoft.Extensions.Logging" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Extensions.Options.ConfigurationExtensions" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="Microsoft.Extensions.Options.ConfigurationExtensions" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Extensions.Options" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="Microsoft.Extensions.Options" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.NETCore.App.Ref" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="Microsoft.NETCore.App.Ref" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
     <!--
          Win-x64 is used here because we have picked an arbitrary runtime identifier to flow the version of the latest NETCore.App runtime.
          All Runtime.$rid packages should have the same version.
     -->
-    <Dependency Name="Microsoft.NETCore.App.Runtime.win-x64" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="Microsoft.NETCore.App.Runtime.win-x64" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="System.Collections.Immutable" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="System.Collections.Immutable" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="System.Configuration.ConfigurationManager" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="System.Configuration.ConfigurationManager" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="System.Diagnostics.DiagnosticSource" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="System.Diagnostics.DiagnosticSource" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="System.Diagnostics.PerformanceCounter" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="System.Diagnostics.PerformanceCounter" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="System.IO.Hashing" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="System.IO.Hashing" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="System.IO.Pipelines" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="System.IO.Pipelines" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="System.Memory.Data" Version="9.0.8">
+    <Dependency Name="System.Memory.Data" Version="9.0.9">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="System.Net.Http.Json" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="System.Net.Http.Json" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="System.Numerics.Tensors" Version="9.0.8">
+    <Dependency Name="System.Numerics.Tensors" Version="9.0.9">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="System.Runtime.Caching" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="System.Runtime.Caching" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="System.Security.Cryptography.Pkcs" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="System.Security.Cryptography.Pkcs" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="System.Security.Cryptography.Xml" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="System.Security.Cryptography.Xml" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="System.Text.Encodings.Web" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="System.Text.Encodings.Web" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="System.Text.Json" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="System.Text.Json" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="System.Threading.Channels" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="System.Threading.Channels" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-runtime</Uri>
-      <Sha>aae90fa09086a9be09dac83fa66542232c7269d8</Sha>
+      <Sha>893c2ebbd49952ca49e93298148af2d95a61a0a4</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.AspNetCore.App.Ref" Version="9.0.8">
+    <Dependency Name="Microsoft.AspNetCore.App.Ref" Version="9.0.9">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-aspnetcore</Uri>
-      <Sha>215a587e52efa710de84138b0a3374b860b924d8</Sha>
+      <Sha>ff66c263be7ed395794bdaf616322977b8ec897c</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.AspNetCore.App.Runtime.win-x64" Version="9.0.8">
+    <Dependency Name="Microsoft.AspNetCore.App.Runtime.win-x64" Version="9.0.9">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-aspnetcore</Uri>
-      <Sha>215a587e52efa710de84138b0a3374b860b924d8</Sha>
+      <Sha>ff66c263be7ed395794bdaf616322977b8ec897c</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.AspNetCore.Mvc.Testing" Version="9.0.8">
+    <Dependency Name="Microsoft.AspNetCore.Mvc.Testing" Version="9.0.9">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-aspnetcore</Uri>
-      <Sha>215a587e52efa710de84138b0a3374b860b924d8</Sha>
+      <Sha>ff66c263be7ed395794bdaf616322977b8ec897c</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.AspNetCore.TestHost" Version="9.0.8">
+    <Dependency Name="Microsoft.AspNetCore.TestHost" Version="9.0.9">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-aspnetcore</Uri>
-      <Sha>215a587e52efa710de84138b0a3374b860b924d8</Sha>
+      <Sha>ff66c263be7ed395794bdaf616322977b8ec897c</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Extensions.Caching.SqlServer" Version="9.0.8">
+    <Dependency Name="Microsoft.Extensions.Caching.SqlServer" Version="9.0.9">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-aspnetcore</Uri>
-      <Sha>215a587e52efa710de84138b0a3374b860b924d8</Sha>
+      <Sha>ff66c263be7ed395794bdaf616322977b8ec897c</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Extensions.Caching.StackExchangeRedis" Version="9.0.8">
+    <Dependency Name="Microsoft.Extensions.Caching.StackExchangeRedis" Version="9.0.9">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-aspnetcore</Uri>
-      <Sha>215a587e52efa710de84138b0a3374b860b924d8</Sha>
+      <Sha>ff66c263be7ed395794bdaf616322977b8ec897c</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Extensions.Diagnostics.HealthChecks" Version="9.0.8">
+    <Dependency Name="Microsoft.Extensions.Diagnostics.HealthChecks" Version="9.0.9">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-aspnetcore</Uri>
-      <Sha>215a587e52efa710de84138b0a3374b860b924d8</Sha>
+      <Sha>ff66c263be7ed395794bdaf616322977b8ec897c</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Extensions.Http.Polly" Version="9.0.8">
+    <Dependency Name="Microsoft.Extensions.Http.Polly" Version="9.0.9">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-aspnetcore</Uri>
-      <Sha>215a587e52efa710de84138b0a3374b860b924d8</Sha>
+      <Sha>ff66c263be7ed395794bdaf616322977b8ec897c</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Extensions.ObjectPool" Version="9.0.8">
+    <Dependency Name="Microsoft.Extensions.ObjectPool" Version="9.0.9">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-aspnetcore</Uri>
-      <Sha>215a587e52efa710de84138b0a3374b860b924d8</Sha>
+      <Sha>ff66c263be7ed395794bdaf616322977b8ec897c</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.EntityFrameworkCore.Sqlite" Version="9.0.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
+    <Dependency Name="Microsoft.EntityFrameworkCore.Sqlite" Version="9.0.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.win-x64">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-efcore</Uri>
-      <Sha>3f7d40ec7be104358780955b3f0fea62495264dc</Sha>
+      <Sha>78871c83aac6c38eb5476c2f34aae98ef65314f5</Sha>
     </Dependency>
   </ProductDependencies>
   <ToolsetDependencies>
diff --git a/eng/Versions.props b/eng/Versions.props
index f79956ce23f..976ec2693dc 100644
--- a/eng/Versions.props
+++ b/eng/Versions.props
@@ -10,14 +10,14 @@
     <!--
         When StabilizePackageVersion is set to 'true', this branch will produce stable outputs for 'Shipping' packages
     -->
-    <StabilizePackageVersion Condition="'$(StabilizePackageVersion)' == ''">false</StabilizePackageVersion>
+    <StabilizePackageVersion Condition="'$(StabilizePackageVersion)' == ''">true</StabilizePackageVersion>
     <!--
         When DotNetFinalVersionKind is set to 'release' (only for the release branches),
         the build will produce stable outputs for 'Shipping' packages.
 
         This is used by the Arcade SDK (Publish.proj) to determine if the build is a release build or not.
       -->
-    <DotNetFinalVersionKind />
+    <DotNetFinalVersionKind>release</DotNetFinalVersionKind>
     <!-- Enabling this rule will cause build failures on undocumented public APIs. -->
     <SkipArcadeNoWarnCS1591>true</SkipArcadeNoWarnCS1591>
   </PropertyGroup>
@@ -33,55 +33,55 @@
   -->
   <PropertyGroup Label="Automated Maestro dependency updates">
     <!-- Packages from dotnet/runtime -->
-    <MicrosoftBclAsyncInterfacesVersion>9.0.8</MicrosoftBclAsyncInterfacesVersion>
-    <MicrosoftBclTimeProviderVersion>9.0.8</MicrosoftBclTimeProviderVersion>
-    <MicrosoftExtensionsCachingAbstractionsVersion>9.0.8</MicrosoftExtensionsCachingAbstractionsVersion>
-    <MicrosoftExtensionsCachingMemoryVersion>9.0.8</MicrosoftExtensionsCachingMemoryVersion>
-    <MicrosoftExtensionsConfigurationAbstractionsVersion>9.0.8</MicrosoftExtensionsConfigurationAbstractionsVersion>
-    <MicrosoftExtensionsConfigurationBinderVersion>9.0.8</MicrosoftExtensionsConfigurationBinderVersion>
-    <MicrosoftExtensionsConfigurationJsonVersion>9.0.8</MicrosoftExtensionsConfigurationJsonVersion>
-    <MicrosoftExtensionsConfigurationVersion>9.0.8</MicrosoftExtensionsConfigurationVersion>
-    <MicrosoftExtensionsDependencyInjectionAbstractionsVersion>9.0.8</MicrosoftExtensionsDependencyInjectionAbstractionsVersion>
-    <MicrosoftExtensionsDependencyInjectionVersion>9.0.8</MicrosoftExtensionsDependencyInjectionVersion>
-    <MicrosoftExtensionsDiagnosticsVersion>9.0.8</MicrosoftExtensionsDiagnosticsVersion>
-    <MicrosoftExtensionsHostingAbstractionsVersion>9.0.8</MicrosoftExtensionsHostingAbstractionsVersion>
-    <MicrosoftExtensionsHostingVersion>9.0.8</MicrosoftExtensionsHostingVersion>
-    <MicrosoftExtensionsHttpVersion>9.0.8</MicrosoftExtensionsHttpVersion>
-    <MicrosoftExtensionsLoggingAbstractionsVersion>9.0.8</MicrosoftExtensionsLoggingAbstractionsVersion>
-    <MicrosoftExtensionsLoggingConfigurationVersion>9.0.8</MicrosoftExtensionsLoggingConfigurationVersion>
-    <MicrosoftExtensionsLoggingConsoleVersion>9.0.8</MicrosoftExtensionsLoggingConsoleVersion>
-    <MicrosoftExtensionsLoggingVersion>9.0.8</MicrosoftExtensionsLoggingVersion>
-    <MicrosoftExtensionsOptionsConfigurationExtensionsVersion>9.0.8</MicrosoftExtensionsOptionsConfigurationExtensionsVersion>
-    <MicrosoftExtensionsOptionsVersion>9.0.8</MicrosoftExtensionsOptionsVersion>
-    <MicrosoftNETCoreAppRefVersion>9.0.8</MicrosoftNETCoreAppRefVersion>
-    <MicrosoftNETCoreAppRuntimewinx64Version>9.0.8</MicrosoftNETCoreAppRuntimewinx64Version>
-    <SystemCollectionsImmutableVersion>9.0.8</SystemCollectionsImmutableVersion>
-    <SystemConfigurationConfigurationManagerVersion>9.0.8</SystemConfigurationConfigurationManagerVersion>
-    <SystemDiagnosticsDiagnosticSourceVersion>9.0.8</SystemDiagnosticsDiagnosticSourceVersion>
-    <SystemDiagnosticsPerformanceCounterVersion>9.0.8</SystemDiagnosticsPerformanceCounterVersion>
-    <SystemIOHashingVersion>9.0.8</SystemIOHashingVersion>
-    <SystemIOPipelinesVersion>9.0.8</SystemIOPipelinesVersion>
-    <SystemMemoryDataVersion>9.0.8</SystemMemoryDataVersion>
-    <SystemNetHttpJsonVersion>9.0.8</SystemNetHttpJsonVersion>
-    <SystemRuntimeCachingVersion>9.0.8</SystemRuntimeCachingVersion>
-    <SystemSecurityCryptographyPkcsVersion>9.0.8</SystemSecurityCryptographyPkcsVersion>
-    <SystemSecurityCryptographyXmlVersion>9.0.8</SystemSecurityCryptographyXmlVersion>
-    <SystemTextEncodingsWebVersion>9.0.8</SystemTextEncodingsWebVersion>
-    <SystemNumericsTensorsVersion>9.0.8</SystemNumericsTensorsVersion>
-    <SystemTextJsonVersion>9.0.8</SystemTextJsonVersion>
-    <SystemThreadingChannelsVersion>9.0.8</SystemThreadingChannelsVersion>
+    <MicrosoftBclAsyncInterfacesVersion>9.0.9</MicrosoftBclAsyncInterfacesVersion>
+    <MicrosoftBclTimeProviderVersion>9.0.9</MicrosoftBclTimeProviderVersion>
+    <MicrosoftExtensionsCachingAbstractionsVersion>9.0.9</MicrosoftExtensionsCachingAbstractionsVersion>
+    <MicrosoftExtensionsCachingMemoryVersion>9.0.9</MicrosoftExtensionsCachingMemoryVersion>
+    <MicrosoftExtensionsConfigurationAbstractionsVersion>9.0.9</MicrosoftExtensionsConfigurationAbstractionsVersion>
+    <MicrosoftExtensionsConfigurationBinderVersion>9.0.9</MicrosoftExtensionsConfigurationBinderVersion>
+    <MicrosoftExtensionsConfigurationJsonVersion>9.0.9</MicrosoftExtensionsConfigurationJsonVersion>
+    <MicrosoftExtensionsConfigurationVersion>9.0.9</MicrosoftExtensionsConfigurationVersion>
+    <MicrosoftExtensionsDependencyInjectionAbstractionsVersion>9.0.9</MicrosoftExtensionsDependencyInjectionAbstractionsVersion>
+    <MicrosoftExtensionsDependencyInjectionVersion>9.0.9</MicrosoftExtensionsDependencyInjectionVersion>
+    <MicrosoftExtensionsDiagnosticsVersion>9.0.9</MicrosoftExtensionsDiagnosticsVersion>
+    <MicrosoftExtensionsHostingAbstractionsVersion>9.0.9</MicrosoftExtensionsHostingAbstractionsVersion>
+    <MicrosoftExtensionsHostingVersion>9.0.9</MicrosoftExtensionsHostingVersion>
+    <MicrosoftExtensionsHttpVersion>9.0.9</MicrosoftExtensionsHttpVersion>
+    <MicrosoftExtensionsLoggingAbstractionsVersion>9.0.9</MicrosoftExtensionsLoggingAbstractionsVersion>
+    <MicrosoftExtensionsLoggingConfigurationVersion>9.0.9</MicrosoftExtensionsLoggingConfigurationVersion>
+    <MicrosoftExtensionsLoggingConsoleVersion>9.0.9</MicrosoftExtensionsLoggingConsoleVersion>
+    <MicrosoftExtensionsLoggingVersion>9.0.9</MicrosoftExtensionsLoggingVersion>
+    <MicrosoftExtensionsOptionsConfigurationExtensionsVersion>9.0.9</MicrosoftExtensionsOptionsConfigurationExtensionsVersion>
+    <MicrosoftExtensionsOptionsVersion>9.0.9</MicrosoftExtensionsOptionsVersion>
+    <MicrosoftNETCoreAppRefVersion>9.0.9</MicrosoftNETCoreAppRefVersion>
+    <MicrosoftNETCoreAppRuntimewinx64Version>9.0.9</MicrosoftNETCoreAppRuntimewinx64Version>
+    <SystemCollectionsImmutableVersion>9.0.9</SystemCollectionsImmutableVersion>
+    <SystemConfigurationConfigurationManagerVersion>9.0.9</SystemConfigurationConfigurationManagerVersion>
+    <SystemDiagnosticsDiagnosticSourceVersion>9.0.9</SystemDiagnosticsDiagnosticSourceVersion>
+    <SystemDiagnosticsPerformanceCounterVersion>9.0.9</SystemDiagnosticsPerformanceCounterVersion>
+    <SystemIOHashingVersion>9.0.9</SystemIOHashingVersion>
+    <SystemIOPipelinesVersion>9.0.9</SystemIOPipelinesVersion>
+    <SystemMemoryDataVersion>9.0.9</SystemMemoryDataVersion>
+    <SystemNetHttpJsonVersion>9.0.9</SystemNetHttpJsonVersion>
+    <SystemRuntimeCachingVersion>9.0.9</SystemRuntimeCachingVersion>
+    <SystemSecurityCryptographyPkcsVersion>9.0.9</SystemSecurityCryptographyPkcsVersion>
+    <SystemSecurityCryptographyXmlVersion>9.0.9</SystemSecurityCryptographyXmlVersion>
+    <SystemTextEncodingsWebVersion>9.0.9</SystemTextEncodingsWebVersion>
+    <SystemNumericsTensorsVersion>9.0.9</SystemNumericsTensorsVersion>
+    <SystemTextJsonVersion>9.0.9</SystemTextJsonVersion>
+    <SystemThreadingChannelsVersion>9.0.9</SystemThreadingChannelsVersion>
     <!-- Dependencies from https://github.com/aspnet/AspNetCore -->
-    <MicrosoftAspNetCoreAppRefVersion>9.0.8</MicrosoftAspNetCoreAppRefVersion>
-    <MicrosoftAspNetCoreAppRuntimewinx64Version>9.0.8</MicrosoftAspNetCoreAppRuntimewinx64Version>
-    <MicrosoftAspNetCoreMvcTestingVersion>9.0.8</MicrosoftAspNetCoreMvcTestingVersion>
-    <MicrosoftAspNetCoreTestHostVersion>9.0.8</MicrosoftAspNetCoreTestHostVersion>
-    <MicrosoftExtensionsCachingSqlServerVersion>9.0.8</MicrosoftExtensionsCachingSqlServerVersion>
-    <MicrosoftExtensionsCachingStackExchangeRedisVersion>9.0.8</MicrosoftExtensionsCachingStackExchangeRedisVersion>
-    <MicrosoftExtensionsDiagnosticsHealthChecksVersion>9.0.8</MicrosoftExtensionsDiagnosticsHealthChecksVersion>
-    <MicrosoftExtensionsHttpPollyVersion>9.0.8</MicrosoftExtensionsHttpPollyVersion>
-    <MicrosoftExtensionsObjectPoolVersion>9.0.8</MicrosoftExtensionsObjectPoolVersion>
+    <MicrosoftAspNetCoreAppRefVersion>9.0.9</MicrosoftAspNetCoreAppRefVersion>
+    <MicrosoftAspNetCoreAppRuntimewinx64Version>9.0.9</MicrosoftAspNetCoreAppRuntimewinx64Version>
+    <MicrosoftAspNetCoreMvcTestingVersion>9.0.9</MicrosoftAspNetCoreMvcTestingVersion>
+    <MicrosoftAspNetCoreTestHostVersion>9.0.9</MicrosoftAspNetCoreTestHostVersion>
+    <MicrosoftExtensionsCachingSqlServerVersion>9.0.9</MicrosoftExtensionsCachingSqlServerVersion>
+    <MicrosoftExtensionsCachingStackExchangeRedisVersion>9.0.9</MicrosoftExtensionsCachingStackExchangeRedisVersion>
+    <MicrosoftExtensionsDiagnosticsHealthChecksVersion>9.0.9</MicrosoftExtensionsDiagnosticsHealthChecksVersion>
+    <MicrosoftExtensionsHttpPollyVersion>9.0.9</MicrosoftExtensionsHttpPollyVersion>
+    <MicrosoftExtensionsObjectPoolVersion>9.0.9</MicrosoftExtensionsObjectPoolVersion>
     <!-- Dependencies from https://github.com/dotnet/efcore -->
-    <MicrosoftEntityFrameworkCoreSqliteVersion>9.0.8</MicrosoftEntityFrameworkCoreSqliteVersion>
+    <MicrosoftEntityFrameworkCoreSqliteVersion>9.0.9</MicrosoftEntityFrameworkCoreSqliteVersion>
     <!-- Dependencies from https://github.com/dotnet/arcade -->
     <MicrosoftDotNetBuildTasksTemplatingVersion>9.0.0-beta.25428.3</MicrosoftDotNetBuildTasksTemplatingVersion>
   </PropertyGroup>
@@ -107,8 +107,8 @@
     <MicrosoftExtensionsLoggingLTSVersion>8.0.1</MicrosoftExtensionsLoggingLTSVersion>
     <MicrosoftExtensionsOptionsConfigurationExtensionsLTSVersion>8.0.0</MicrosoftExtensionsOptionsConfigurationExtensionsLTSVersion>
     <MicrosoftExtensionsOptionsLTSVersion>8.0.2</MicrosoftExtensionsOptionsLTSVersion>
-    <MicrosoftNETCoreAppRefLTSVersion>8.0.19</MicrosoftNETCoreAppRefLTSVersion>
-    <MicrosoftNETCoreAppRuntimewinx64LTSVersion>8.0.19</MicrosoftNETCoreAppRuntimewinx64LTSVersion>
+    <MicrosoftNETCoreAppRefLTSVersion>8.0.20</MicrosoftNETCoreAppRefLTSVersion>
+    <MicrosoftNETCoreAppRuntimewinx64LTSVersion>8.0.20</MicrosoftNETCoreAppRuntimewinx64LTSVersion>
     <SystemCollectionsImmutableLTSVersion>8.0.0</SystemCollectionsImmutableLTSVersion>
     <SystemConfigurationConfigurationManagerLTSVersion>8.0.1</SystemConfigurationConfigurationManagerLTSVersion>
     <SystemDiagnosticsDiagnosticSourceLTSVersion>8.0.1</SystemDiagnosticsDiagnosticSourceLTSVersion>
@@ -125,17 +125,17 @@
     <SystemTextJsonLTSVersion>8.0.6</SystemTextJsonLTSVersion>
     <SystemThreadingChannelsLTSVersion>8.0.0</SystemThreadingChannelsLTSVersion>
     <!-- Dependencies from https://github.com/aspnet/AspNetCore -->
-    <MicrosoftAspNetCoreAppRefLTSVersion>8.0.19</MicrosoftAspNetCoreAppRefLTSVersion>
-    <MicrosoftAspNetCoreAppRuntimewinx64LTSVersion>8.0.19</MicrosoftAspNetCoreAppRuntimewinx64LTSVersion>
-    <MicrosoftAspNetCoreMvcTestingLTSVersion>8.0.19</MicrosoftAspNetCoreMvcTestingLTSVersion>
-    <MicrosoftAspNetCoreTestHostLTSVersion>8.0.19</MicrosoftAspNetCoreTestHostLTSVersion>
-    <MicrosoftExtensionsCachingSqlServerLTSVersion>8.0.19</MicrosoftExtensionsCachingSqlServerLTSVersion>
-    <MicrosoftExtensionsCachingStackExchangeRedisLTSVersion>8.0.19</MicrosoftExtensionsCachingStackExchangeRedisLTSVersion>
-    <MicrosoftExtensionsDiagnosticsHealthChecksLTSVersion>8.0.19</MicrosoftExtensionsDiagnosticsHealthChecksLTSVersion>
-    <MicrosoftExtensionsHttpPollyLTSVersion>8.0.19</MicrosoftExtensionsHttpPollyLTSVersion>
-    <MicrosoftExtensionsObjectPoolLTSVersion>8.0.19</MicrosoftExtensionsObjectPoolLTSVersion>
+    <MicrosoftAspNetCoreAppRefLTSVersion>8.0.20</MicrosoftAspNetCoreAppRefLTSVersion>
+    <MicrosoftAspNetCoreAppRuntimewinx64LTSVersion>8.0.20</MicrosoftAspNetCoreAppRuntimewinx64LTSVersion>
+    <MicrosoftAspNetCoreMvcTestingLTSVersion>8.0.20</MicrosoftAspNetCoreMvcTestingLTSVersion>
+    <MicrosoftAspNetCoreTestHostLTSVersion>8.0.20</MicrosoftAspNetCoreTestHostLTSVersion>
+    <MicrosoftExtensionsCachingSqlServerLTSVersion>8.0.20</MicrosoftExtensionsCachingSqlServerLTSVersion>
+    <MicrosoftExtensionsCachingStackExchangeRedisLTSVersion>8.0.20</MicrosoftExtensionsCachingStackExchangeRedisLTSVersion>
+    <MicrosoftExtensionsDiagnosticsHealthChecksLTSVersion>8.0.20</MicrosoftExtensionsDiagnosticsHealthChecksLTSVersion>
+    <MicrosoftExtensionsHttpPollyLTSVersion>8.0.20</MicrosoftExtensionsHttpPollyLTSVersion>
+    <MicrosoftExtensionsObjectPoolLTSVersion>8.0.20</MicrosoftExtensionsObjectPoolLTSVersion>
     <!-- Dependencies from https://github.com/dotnet/efcore -->
-    <MicrosoftEntityFrameworkCoreSqliteLTSVersion>8.0.19</MicrosoftEntityFrameworkCoreSqliteLTSVersion>
+    <MicrosoftEntityFrameworkCoreSqliteLTSVersion>8.0.20</MicrosoftEntityFrameworkCoreSqliteLTSVersion>
   </PropertyGroup>
   <!--
 
diff --git a/eng/pipelines/templates/BuildAndTest.yml b/eng/pipelines/templates/BuildAndTest.yml
index bd008ead075..6c54a911e84 100644
--- a/eng/pipelines/templates/BuildAndTest.yml
+++ b/eng/pipelines/templates/BuildAndTest.yml
@@ -28,6 +28,23 @@ steps:
     inputs:
       versionSpec: "20.x"
       checkLatest: true
+  - task: PowerShell@2
+    displayName: Setup Private Feeds Credentials
+    condition: eq(variables['Agent.OS'], 'Windows_NT')
+    inputs:
+      filePath: $(Build.SourcesDirectory)/eng/common/SetupNugetSources.ps1
+      arguments: -ConfigFile $(Build.SourcesDirectory)/NuGet.config -Password $Env:Token
+    env:
+      Token: $(dn-bot-dnceng-artifact-feeds-rw)
+
+  - task: Bash@3
+    displayName: Setup Private Feeds Credentials
+    condition: ne(variables['Agent.OS'], 'Windows_NT')
+    inputs:
+      filePath: $(Build.SourcesDirectory)/eng/common/SetupNugetSources.sh
+      arguments: $(Build.SourcesDirectory)/NuGet.config $Token
+    env:
+      Token: $(dn-bot-dnceng-artifact-feeds-rw)
 
   - script: ${{ parameters.buildScript }}
             -restore
@@ -68,13 +85,14 @@ steps:
     displayName: Pack
     
   - ${{ if ne(parameters.skipTests, 'true') }}:
-    - script: ${{ parameters.buildScript }}
-              -integrationTest
-              -configuration ${{ parameters.buildConfig }}
-              -warnAsError 1
-              /bl:${{ parameters.repoLogPath }}/integration_tests.binlog
-              $(_OfficialBuildIdArgs)
-      displayName: Run integration tests
+    # Skipping integration tests for now as they require authentication to the private feeds
+    # - script: ${{ parameters.buildScript }}
+    #           -integrationTest
+    #           -configuration ${{ parameters.buildConfig }}
+    #           -warnAsError 1
+    #           /bl:${{ parameters.repoLogPath }}/integration_tests.binlog
+    #           $(_OfficialBuildIdArgs)
+    #   displayName: Run integration tests
 
     - pwsh: |
         $SourcesDirectory = '$(Build.SourcesDirectory)';

From d62ee42d8e4862ae760f3abfb10a9a7df56be9fb Mon Sep 17 00:00:00 2001
From: Roger Barreto <19890735+rogerbarreto@users.noreply.github.com>
Date: Fri, 5 Sep 2025 03:19:58 +0100
Subject: [PATCH 2/8] Add reasoning text content for OpenAI Responses
 ChatClient Streaming (#6761)

* Add reasoning text content for OpenAI Responses ChatClient Streaming

---------

Co-authored-by: Stephen Toub <stoub@microsoft.com>
---
 .../OpenAIResponsesChatClient.cs              |  15 ++
 .../OpenAIResponseClientTests.cs              | 180 ++++++++++++++++++
 2 files changed, 195 insertions(+)

diff --git a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponsesChatClient.cs b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponsesChatClient.cs
index e1cd031f8a8..b5d3c09de32 100644
--- a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponsesChatClient.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponsesChatClient.cs
@@ -4,6 +4,7 @@
 using System;
 using System.ClientModel.Primitives;
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Reflection;
 using System.Runtime.CompilerServices;
@@ -26,6 +27,11 @@ namespace Microsoft.Extensions.AI;
 /// <summary>Represents an <see cref="IChatClient"/> for an <see cref="OpenAIResponseClient"/>.</summary>
 internal sealed class OpenAIResponsesChatClient : IChatClient
 {
+    // Fix this to not use reflection once https://github.com/openai/openai-dotnet/issues/643 is addressed.
+    [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicProperties)]
+    private static readonly Type? _internalResponseReasoningSummaryTextDeltaEventType = Type.GetType("OpenAI.Responses.InternalResponseReasoningSummaryTextDeltaEvent, OpenAI");
+    private static readonly PropertyInfo? _summaryTextDeltaProperty = _internalResponseReasoningSummaryTextDeltaEventType?.GetProperty("Delta");
+
     /// <summary>Metadata about the client.</summary>
     private readonly ChatClientMetadata _metadata;
 
@@ -324,8 +330,17 @@ ChatResponseUpdate CreateUpdate(AIContent? content = null) =>
                     break;
 
                 default:
+                {
+                    if (streamingUpdate.GetType() == _internalResponseReasoningSummaryTextDeltaEventType &&
+                        _summaryTextDeltaProperty?.GetValue(streamingUpdate) is string delta)
+                    {
+                        yield return CreateUpdate(new TextReasoningContent(delta));
+                        break;
+                    }
+
                     yield return CreateUpdate();
                     break;
+                }
             }
         }
     }
diff --git a/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIResponseClientTests.cs b/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIResponseClientTests.cs
index 72df6002ca2..ca71aee550f 100644
--- a/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIResponseClientTests.cs
+++ b/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIResponseClientTests.cs
@@ -168,6 +168,186 @@ public async Task BasicRequestResponse_NonStreaming()
         Assert.Equal(36, response.Usage.TotalTokenCount);
     }
 
+    [Fact]
+    public async Task BasicReasoningResponse_Streaming()
+    {
+        const string Input = """
+            {
+              "input":[{
+                "type":"message",
+                "role":"user",
+                "content":[{
+                  "type":"input_text",
+                  "text":"Calculate the sum of the first 5 positive integers."
+                }]
+              }],
+              "reasoning": {
+                "summary": "detailed",
+                "effort": "low"
+              },
+              "model": "o4-mini",
+              "stream": true
+            }
+            """;
+
+        // Compressed down for testing purposes; real-world output would be larger.
+        const string Output = """
+            event: response.created
+            data: {"type":"response.created","sequence_number":0,"response":{"id":"resp_68b5ebab461881969ed94149372c2a530698ecbf1b9f2704","object":"response","created_at":1756752811,"status":"in_progress","background":false,"error":null,"incomplete_details":null,"instructions":null,"max_output_tokens":null,"max_tool_calls":null,"model":"o4-mini-2025-04-16","output":[],"parallel_tool_calls":true,"previous_response_id":null,"prompt_cache_key":null,"reasoning":{"effort":"low","summary":"detailed"},"safety_identifier":null,"service_tier":"auto","store":true,"temperature":1.0,"text":{"format":{"type":"text"},"verbosity":"medium"},"tool_choice":"auto","tools":[],"top_logprobs":0,"top_p":1.0,"truncation":"disabled","usage":null,"user":null,"metadata":{}}}
+
+            event: response.in_progress
+            data: {"type":"response.in_progress","sequence_number":1,"response":{"id":"resp_68b5ebab461881969ed94149372c2a530698ecbf1b9f2704","object":"response","created_at":1756752811,"status":"in_progress","background":false,"error":null,"incomplete_details":null,"instructions":null,"max_output_tokens":null,"max_tool_calls":null,"model":"o4-mini-2025-04-16","output":[],"parallel_tool_calls":true,"previous_response_id":null,"prompt_cache_key":null,"reasoning":{"effort":"low","summary":"detailed"},"safety_identifier":null,"service_tier":"auto","store":true,"temperature":1.0,"text":{"format":{"type":"text"},"verbosity":"medium"},"tool_choice":"auto","tools":[],"top_logprobs":0,"top_p":1.0,"truncation":"disabled","usage":null,"user":null,"metadata":{}}}
+
+            event: response.output_item.added
+            data: {"type":"response.output_item.added","sequence_number":2,"output_index":0,"item":{"id":"rs_68b5ebabc0088196afb9fa86b487732d0698ecbf1b9f2704","type":"reasoning","summary":[]}}
+
+            event: response.reasoning_summary_part.added
+            data: {"type":"response.reasoning_summary_part.added","sequence_number":3,"item_id":"rs_68b5ebabc0088196afb9fa86b487732d0698ecbf1b9f2704","output_index":0,"summary_index":0,"part":{"type":"summary_text","text":""}}
+
+            event: response.reasoning_summary_text.delta
+            data: {"type":"response.reasoning_summary_text.delta","sequence_number":4,"item_id":"rs_68b5ebabc0088196afb9fa86b487732d0698ecbf1b9f2704","output_index":0,"summary_index":0,"delta":"**Calcul","obfuscation":"sLkbFySM"}
+
+            event: response.reasoning_summary_text.delta
+            data: {"type":"response.reasoning_summary_text.delta","sequence_number":5,"item_id":"rs_68b5ebabc0088196afb9fa86b487732d0698ecbf1b9f2704","output_index":0,"summary_index":0,"delta":"ating","obfuscation":"dkm1f6DKqUj"}
+
+            event: response.reasoning_summary_text.delta
+            data: {"type":"response.reasoning_summary_text.delta","sequence_number":6,"item_id":"rs_68b5ebabc0088196afb9fa86b487732d0698ecbf1b9f2704","output_index":0,"summary_index":0,"delta":" a","obfuscation":"X8ahc2lfCf9eA1"}
+
+            event: response.reasoning_summary_text.delta
+            data: {"type":"response.reasoning_summary_text.delta","sequence_number":7,"item_id":"rs_68b5ebabc0088196afb9fa86b487732d0698ecbf1b9f2704","output_index":0,"summary_index":0,"delta":" simple","obfuscation":"1rLVyIaNl"}
+
+            event: response.reasoning_summary_text.delta
+            data: {"type":"response.reasoning_summary_text.delta","sequence_number":8,"item_id":"rs_68b5ebabc0088196afb9fa86b487732d0698ecbf1b9f2704","output_index":0,"summary_index":0,"delta":" sum","obfuscation":"jCK7mgNR80Re"}
+
+            event: response.reasoning_summary_text.done
+            data: {"type":"response.reasoning_summary_text.done","sequence_number":9,"item_id":"rs_68b5ebabc0088196afb9fa86b487732d0698ecbf1b9f2704","output_index":0,"summary_index":0,"text":"**Calculating a simple sum**"}
+
+            event: response.reasoning_summary_part.done
+            data: {"type":"response.reasoning_summary_part.done","sequence_number":10,"item_id":"rs_68b5ebabc0088196afb9fa86b487732d0698ecbf1b9f2704","output_index":0,"summary_index":0,"part":{"type":"summary_text","text":"**Calculating a simple sum**"}}
+
+            event: response.output_item.done
+            data: {"type":"response.output_item.done","sequence_number":11,"output_index":0,"item":{"id":"rs_68b5ebabc0088196afb9fa86b487732d0698ecbf1b9f2704","type":"reasoning","summary":[{"type":"summary_text","text":"**Calculating a simple sum**"}]}}
+
+            event: response.output_item.added
+            data: {"type":"response.output_item.added","sequence_number":12,"output_index":1,"item":{"id":"msg_68b5ebae5a708196b74b94f22ca8995e0698ecbf1b9f2704","type":"message","status":"in_progress","content":[],"role":"assistant"}}
+
+            event: response.content_part.added
+            data: {"type":"response.content_part.added","sequence_number":13,"item_id":"msg_68b5ebae5a708196b74b94f22ca8995e0698ecbf1b9f2704","output_index":1,"content_index":0,"part":{"type":"output_text","annotations":[],"logprobs":[],"text":""}}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":14,"item_id":"msg_68b5ebae5a708196b74b94f22ca8995e0698ecbf1b9f2704","output_index":1,"content_index":0,"delta":"The","logprobs":[],"obfuscation":"japg2KaCkjNsp"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":15,"item_id":"msg_68b5ebae5a708196b74b94f22ca8995e0698ecbf1b9f2704","output_index":1,"content_index":0,"delta":" sum","logprobs":[],"obfuscation":"1BEqjKQ0KU41"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":16,"item_id":"msg_68b5ebae5a708196b74b94f22ca8995e0698ecbf1b9f2704","output_index":1,"content_index":0,"delta":" of","logprobs":[],"obfuscation":"GUqom1rsdZsnT"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":17,"item_id":"msg_68b5ebae5a708196b74b94f22ca8995e0698ecbf1b9f2704","output_index":1,"content_index":0,"delta":" the","logprobs":[],"obfuscation":"UmCms91yrTlg"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":18,"item_id":"msg_68b5ebae5a708196b74b94f22ca8995e0698ecbf1b9f2704","output_index":1,"content_index":0,"delta":" first","logprobs":[],"obfuscation":"AyNbZpfTXo"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":19,"item_id":"msg_68b5ebae5a708196b74b94f22ca8995e0698ecbf1b9f2704","output_index":1,"content_index":0,"delta":" ","logprobs":[],"obfuscation":"tuyz4HkKODFQRtk"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":20,"item_id":"msg_68b5ebae5a708196b74b94f22ca8995e0698ecbf1b9f2704","output_index":1,"content_index":0,"delta":"5","logprobs":[],"obfuscation":"QAwyISolmjXfTlc"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":21,"item_id":"msg_68b5ebae5a708196b74b94f22ca8995e0698ecbf1b9f2704","output_index":1,"content_index":0,"delta":" positive","logprobs":[],"obfuscation":"2Euge1H"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":22,"item_id":"msg_68b5ebae5a708196b74b94f22ca8995e0698ecbf1b9f2704","output_index":1,"content_index":0,"delta":" integers","logprobs":[],"obfuscation":"ih0Znt8"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":23,"item_id":"msg_68b5ebae5a708196b74b94f22ca8995e0698ecbf1b9f2704","output_index":1,"content_index":0,"delta":" is","logprobs":[],"obfuscation":"oQihR5Pw8jRz5"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":24,"item_id":"msg_68b5ebae5a708196b74b94f22ca8995e0698ecbf1b9f2704","output_index":1,"content_index":0,"delta":" 15","logprobs":[],"obfuscation":"7TdJ1FWlZF8lTd"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":25,"item_id":"msg_68b5ebae5a708196b74b94f22ca8995e0698ecbf1b9f2704","output_index":1,"content_index":0,"delta":".","logprobs":[],"obfuscation":"x2VAJKlWI8qjgYq"}
+
+            event: response.output_text.done
+            data: {"type":"response.output_text.done","sequence_number":26,"item_id":"msg_68b5ebae5a708196b74b94f22ca8995e0698ecbf1b9f2704","output_index":1,"content_index":0,"text":"The sum of the first 5 positive integers is 15.","logprobs":[]}
+
+            event: response.content_part.done
+            data: {"type":"response.content_part.done","sequence_number":27,"item_id":"msg_68b5ebae5a708196b74b94f22ca8995e0698ecbf1b9f2704","output_index":1,"content_index":0,"part":{"type":"output_text","annotations":[],"logprobs":[],"text":"The sum of the first 5 positive integers is 15."}}
+
+            event: response.output_item.done
+            data: {"type":"response.output_item.done","sequence_number":28,"output_index":1,"item":{"id":"msg_68b5ebae5a708196b74b94f22ca8995e0698ecbf1b9f2704","type":"message","status":"completed","content":[{"type":"output_text","annotations":[],"logprobs":[],"text":"The sum of the first 5 positive integers is 15."}],"role":"assistant"}}
+
+            event: response.completed
+            data: {"type":"response.completed","sequence_number":29,"response":{"id":"resp_68b5ebab461881969ed94149372c2a530698ecbf1b9f2704","object":"response","created_at":1756752811,"status":"completed","background":false,"error":null,"incomplete_details":null,"instructions":null,"max_output_tokens":null,"max_tool_calls":null,"model":"o4-mini-2025-04-16","output":[{"id":"rs_68b5ebabc0088196afb9fa86b487732d0698ecbf1b9f2704","type":"reasoning","summary":[{"type":"summary_text","text":"**Calculating a simple sum**"}]},{"id":"msg_68b5ebae5a708196b74b94f22ca8995e0698ecbf1b9f2704","type":"message","status":"completed","content":[{"type":"output_text","annotations":[],"logprobs":[],"text":"The sum of the first 5 positive integers is 15."}],"role":"assistant"}],"parallel_tool_calls":true,"previous_response_id":null,"prompt_cache_key":null,"reasoning":{"effort":"low","summary":"detailed"},"safety_identifier":null,"service_tier":"default","store":true,"temperature":1.0,"text":{"format":{"type":"text"},"verbosity":"medium"},"tool_choice":"auto","tools":[],"top_logprobs":0,"top_p":1.0,"truncation":"disabled","usage":{"input_tokens":17,"input_tokens_details":{"cached_tokens":0},"output_tokens":122,"output_tokens_details":{"reasoning_tokens":64},"total_tokens":139},"user":null,"metadata":{}}}
+
+
+            """;
+
+        using VerbatimHttpHandler handler = new(Input, Output);
+        using HttpClient httpClient = new(handler);
+        using IChatClient client = CreateResponseClient(httpClient, "o4-mini");
+
+        List<ChatResponseUpdate> updates = [];
+        await foreach (var update in client.GetStreamingResponseAsync("Calculate the sum of the first 5 positive integers.", new()
+        {
+            RawRepresentationFactory = options => new ResponseCreationOptions
+            {
+                ReasoningOptions = new()
+                {
+                    ReasoningEffortLevel = ResponseReasoningEffortLevel.Low,
+                    ReasoningSummaryVerbosity = ResponseReasoningSummaryVerbosity.Detailed
+                }
+            }
+        }))
+        {
+            updates.Add(update);
+        }
+
+        Assert.Equal("The sum of the first 5 positive integers is 15.", string.Concat(updates.Select(u => u.Text)));
+
+        var createdAt = DateTimeOffset.FromUnixTimeSeconds(1_756_752_811);
+        Assert.Equal(30, updates.Count);
+
+        for (int i = 0; i < updates.Count; i++)
+        {
+            Assert.Equal("resp_68b5ebab461881969ed94149372c2a530698ecbf1b9f2704", updates[i].ResponseId);
+            Assert.Equal("resp_68b5ebab461881969ed94149372c2a530698ecbf1b9f2704", updates[i].ConversationId);
+            Assert.Equal(createdAt, updates[i].CreatedAt);
+            Assert.Equal("o4-mini-2025-04-16", updates[i].ModelId);
+            Assert.Null(updates[i].AdditionalProperties);
+
+            if (i is (>= 4 and <= 8))
+            {
+                // Reasoning updates
+                Assert.Single(updates[i].Contents);
+                Assert.Null(updates[i].Role);
+
+                var reasoning = Assert.IsType<TextReasoningContent>(updates[i].Contents.Single());
+                Assert.NotNull(reasoning);
+                Assert.NotNull(reasoning.Text);
+            }
+            else if (i is (>= 14 and <= 25) or 29)
+            {
+                // Response Complete and Assistant message updates
+                Assert.Single(updates[i].Contents);
+            }
+            else
+            {
+                // Other updates
+                Assert.Empty(updates[i].Contents);
+            }
+
+            Assert.Equal(i < updates.Count - 1 ? null : ChatFinishReason.Stop, updates[i].FinishReason);
+        }
+
+        UsageContent usage = updates.SelectMany(u => u.Contents).OfType<UsageContent>().Single();
+        Assert.Equal(17, usage.Details.InputTokenCount);
+        Assert.Equal(122, usage.Details.OutputTokenCount);
+        Assert.Equal(139, usage.Details.TotalTokenCount);
+    }
+
     [Fact]
     public async Task BasicRequestResponse_Streaming()
     {

From 933aeb4a08ca8851c59aa8a8780e419ce0b85728 Mon Sep 17 00:00:00 2001
From: westey <164392973+westey-m@users.noreply.github.com>
Date: Fri, 5 Sep 2025 23:30:35 +0100
Subject: [PATCH 3/8] Add function approvals support (#6745)

- Adding an ApprovalRequiredAIFunction that can be used to decorate an AIFunction.
- Adding UserInputRequestContent and UserInputResponseContent base types to represent all user input.
- Adding FunctionApprovalRequestContent and FunctionApprovalResponseContent for function approvals.
- Updated FunctionInvokingChatClient with approval generation handling.

All new types are currently [Experimental].

Co-authored-by: Stephen Toub <stoub@microsoft.com>
---
 .../CHANGELOG.md                              |   1 +
 .../Contents/AIContent.cs                     |   7 +
 .../FunctionApprovalRequestContent.cs         |  41 +
 .../FunctionApprovalResponseContent.cs        |  41 +
 .../Contents/UserInputRequestContent.cs       |  31 +
 .../Contents/UserInputResponseContent.cs      |  31 +
 .../Functions/ApprovalRequiredAIFunction.cs   |  29 +
 .../Microsoft.Extensions.AI/CHANGELOG.md      |   1 +
 .../FunctionInvokingChatClient.cs             | 710 ++++++++++++--
 .../Microsoft.Extensions.AI.csproj            |   2 +-
 .../AssertExtensions.cs                       |  38 +
 .../FunctionApprovalRequestContentTests.cs    |  54 ++
 .../FunctionApprovalResponseContentTests.cs   |  36 +
 .../Contents/UserInputRequestContentTests.cs  |  37 +
 .../Contents/UserInputResponseContentTests.cs |  37 +
 .../ApprovalRequiredAIFunctionTests.cs        |  44 +
 ...unctionInvokingChatClientApprovalsTests.cs | 905 ++++++++++++++++++
 .../FunctionInvokingChatClientTests.cs        |  85 +-
 .../EnumeratedOnceEnumerable.cs               |  29 +
 19 files changed, 2017 insertions(+), 142 deletions(-)
 create mode 100644 src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/FunctionApprovalRequestContent.cs
 create mode 100644 src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/FunctionApprovalResponseContent.cs
 create mode 100644 src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/UserInputRequestContent.cs
 create mode 100644 src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/UserInputResponseContent.cs
 create mode 100644 src/Libraries/Microsoft.Extensions.AI.Abstractions/Functions/ApprovalRequiredAIFunction.cs
 create mode 100644 test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/FunctionApprovalRequestContentTests.cs
 create mode 100644 test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/FunctionApprovalResponseContentTests.cs
 create mode 100644 test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/UserInputRequestContentTests.cs
 create mode 100644 test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/UserInputResponseContentTests.cs
 create mode 100644 test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Functions/ApprovalRequiredAIFunctionTests.cs
 create mode 100644 test/Libraries/Microsoft.Extensions.AI.Tests/ChatCompletion/FunctionInvokingChatClientApprovalsTests.cs
 create mode 100644 test/Libraries/Microsoft.Extensions.AI.Tests/EnumeratedOnceEnumerable.cs

diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/CHANGELOG.md b/src/Libraries/Microsoft.Extensions.AI.Abstractions/CHANGELOG.md
index bd2643ec060..34c83f701c1 100644
--- a/src/Libraries/Microsoft.Extensions.AI.Abstractions/CHANGELOG.md
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/CHANGELOG.md
@@ -3,6 +3,7 @@
 ## NOT YET RELEASED
 
 - Added non-invocable `AIFunctionDeclaration` (base class for `AIFunction`), `AIFunctionFactory.CreateDeclaration`, and `AIFunction.AsDeclarationOnly`.
+- Added `[Experimental]` support for user approval of function invocations via `ApprovalRequiredAIFunction`, `FunctionApprovalRequestContent`, and friends.
 
 ## 9.8.0
 
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/AIContent.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/AIContent.cs
index f9c7603d02a..e3ee10ad50a 100644
--- a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/AIContent.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/AIContent.cs
@@ -18,6 +18,13 @@ namespace Microsoft.Extensions.AI;
 [JsonDerivedType(typeof(TextReasoningContent), typeDiscriminator: "reasoning")]
 [JsonDerivedType(typeof(UriContent), typeDiscriminator: "uri")]
 [JsonDerivedType(typeof(UsageContent), typeDiscriminator: "usage")]
+
+// These should be added in once they're no longer [Experimental]. If they're included while still
+// experimental, any JsonSerializerContext that includes AIContent will incur errors about using
+// experimental types in its source generated files.
+// [JsonDerivedType(typeof(FunctionApprovalRequestContent), typeDiscriminator: "functionApprovalRequest")]
+// [JsonDerivedType(typeof(FunctionApprovalResponseContent), typeDiscriminator: "functionApprovalResponse")]
+
 public class AIContent
 {
     /// <summary>
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/FunctionApprovalRequestContent.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/FunctionApprovalRequestContent.cs
new file mode 100644
index 00000000000..d3ec7ab8f0b
--- /dev/null
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/FunctionApprovalRequestContent.cs
@@ -0,0 +1,41 @@
+// 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.Diagnostics.CodeAnalysis;
+using Microsoft.Shared.Diagnostics;
+
+namespace Microsoft.Extensions.AI;
+
+/// <summary>
+/// Represents a request for user approval of a function call.
+/// </summary>
+[Experimental("MEAI001")]
+public sealed class FunctionApprovalRequestContent : UserInputRequestContent
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="FunctionApprovalRequestContent"/> class.
+    /// </summary>
+    /// <param name="id">The ID that uniquely identifies the function approval request/response pair.</param>
+    /// <param name="functionCall">The function call that requires user approval.</param>
+    /// <exception cref="ArgumentNullException"><paramref name="id"/> is <see langword="null"/>.</exception>
+    /// <exception cref="ArgumentException"><paramref name="id"/> is empty or composed entirely of whitespace.</exception>
+    /// <exception cref="ArgumentNullException"><paramref name="functionCall"/> is <see langword="null"/>.</exception>
+    public FunctionApprovalRequestContent(string id, FunctionCallContent functionCall)
+        : base(id)
+    {
+        FunctionCall = Throw.IfNull(functionCall);
+    }
+
+    /// <summary>
+    /// Gets the function call that pre-invoke approval is required for.
+    /// </summary>
+    public FunctionCallContent FunctionCall { get; }
+
+    /// <summary>
+    /// Creates a <see cref="FunctionApprovalResponseContent"/> to indicate whether the function call is approved or rejected based on the value of <paramref name="approved"/>.
+    /// </summary>
+    /// <param name="approved"><see langword="true"/> if the function call is approved; otherwise, <see langword="false"/>.</param>
+    /// <returns>The <see cref="FunctionApprovalResponseContent"/> representing the approval response.</returns>
+    public FunctionApprovalResponseContent CreateResponse(bool approved) => new(Id, approved, FunctionCall);
+}
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/FunctionApprovalResponseContent.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/FunctionApprovalResponseContent.cs
new file mode 100644
index 00000000000..948dc6a1347
--- /dev/null
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/FunctionApprovalResponseContent.cs
@@ -0,0 +1,41 @@
+// 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.Diagnostics.CodeAnalysis;
+using Microsoft.Shared.Diagnostics;
+
+namespace Microsoft.Extensions.AI;
+
+/// <summary>
+/// Represents a response to a function approval request.
+/// </summary>
+[Experimental("MEAI001")]
+public sealed class FunctionApprovalResponseContent : UserInputResponseContent
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="FunctionApprovalResponseContent"/> class.
+    /// </summary>
+    /// <param name="id">The ID that uniquely identifies the function approval request/response pair.</param>
+    /// <param name="approved"><see langword="true"/> if the function call is approved; otherwise, <see langword="false"/>.</param>
+    /// <param name="functionCall">The function call that requires user approval.</param>
+    /// <exception cref="ArgumentNullException"><paramref name="id"/> is <see langword="null"/>.</exception>
+    /// <exception cref="ArgumentException"><paramref name="id"/> is empty or composed entirely of whitespace.</exception>
+    /// <exception cref="ArgumentNullException"><paramref name="functionCall"/> is <see langword="null"/>.</exception>
+    public FunctionApprovalResponseContent(string id, bool approved, FunctionCallContent functionCall)
+        : base(id)
+    {
+        Approved = approved;
+        FunctionCall = Throw.IfNull(functionCall);
+    }
+
+    /// <summary>
+    /// Gets a value indicating whether the user approved the request.
+    /// </summary>
+    public bool Approved { get; }
+
+    /// <summary>
+    /// Gets the function call for which approval was requested.
+    /// </summary>
+    public FunctionCallContent FunctionCall { get; }
+}
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/UserInputRequestContent.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/UserInputRequestContent.cs
new file mode 100644
index 00000000000..c30cc3351df
--- /dev/null
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/UserInputRequestContent.cs
@@ -0,0 +1,31 @@
+// 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.Diagnostics.CodeAnalysis;
+using Microsoft.Shared.Diagnostics;
+
+namespace Microsoft.Extensions.AI;
+
+/// <summary>
+/// Represents a request for user input.
+/// </summary>
+[Experimental("MEAI001")]
+public class UserInputRequestContent : AIContent
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="UserInputRequestContent"/> class.
+    /// </summary>
+    /// <param name="id">The ID that uniquely identifies the user input request/response pair.</param>
+    /// <exception cref="ArgumentNullException"><paramref name="id"/> is <see langword="null"/>.</exception>
+    /// <exception cref="ArgumentException"><paramref name="id"/> is empty or composed entirely of whitespace.</exception>
+    protected UserInputRequestContent(string id)
+    {
+        Id = Throw.IfNullOrWhitespace(id);
+    }
+
+    /// <summary>
+    /// Gets the ID that uniquely identifies the user input request/response pair.
+    /// </summary>
+    public string Id { get; }
+}
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/UserInputResponseContent.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/UserInputResponseContent.cs
new file mode 100644
index 00000000000..2d436f99bb8
--- /dev/null
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/UserInputResponseContent.cs
@@ -0,0 +1,31 @@
+// 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.Diagnostics.CodeAnalysis;
+using Microsoft.Shared.Diagnostics;
+
+namespace Microsoft.Extensions.AI;
+
+/// <summary>
+/// Represents the response to a request for user input.
+/// </summary>
+[Experimental("MEAI001")]
+public class UserInputResponseContent : AIContent
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="UserInputResponseContent"/> class.
+    /// </summary>
+    /// <param name="id">The ID that uniquely identifies the user input request/response pair.</param>
+    /// <exception cref="ArgumentNullException"><paramref name="id"/> is <see langword="null"/>.</exception>
+    /// <exception cref="ArgumentException"><paramref name="id"/> is empty or composed entirely of whitespace.</exception>
+    protected UserInputResponseContent(string id)
+    {
+        Id = Throw.IfNullOrWhitespace(id);
+    }
+
+    /// <summary>
+    /// Gets the ID that uniquely identifies the user input request/response pair.
+    /// </summary>
+    public string Id { get; }
+}
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Functions/ApprovalRequiredAIFunction.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Functions/ApprovalRequiredAIFunction.cs
new file mode 100644
index 00000000000..994e4660ac1
--- /dev/null
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Functions/ApprovalRequiredAIFunction.cs
@@ -0,0 +1,29 @@
+// 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.Diagnostics.CodeAnalysis;
+
+namespace Microsoft.Extensions.AI;
+
+/// <summary>
+/// Represents an <see cref="AIFunction"/> that can be described to an AI service and invoked, but for which
+/// the invoker should obtain user approval before the function is actually invoked.
+/// </summary>
+/// <remarks>
+/// This class simply augments an <see cref="AIFunction"/> with an indication that approval is required before invocation.
+/// It does not enforce the requirement for user approval; it is the responsibility of the invoker to obtain that approval before invoking the function.
+/// </remarks>
+[Experimental("MEAI001")]
+public sealed class ApprovalRequiredAIFunction : DelegatingAIFunction
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="ApprovalRequiredAIFunction"/> class.
+    /// </summary>
+    /// <param name="innerFunction">The <see cref="AIFunction"/> represented by this instance.</param>
+    /// <exception cref="ArgumentNullException"><paramref name="innerFunction"/> is <see langword="null"/>.</exception>
+    public ApprovalRequiredAIFunction(AIFunction innerFunction)
+        : base(innerFunction)
+    {
+    }
+}
diff --git a/src/Libraries/Microsoft.Extensions.AI/CHANGELOG.md b/src/Libraries/Microsoft.Extensions.AI/CHANGELOG.md
index 6d0c1a3818d..a7c46b1d56d 100644
--- a/src/Libraries/Microsoft.Extensions.AI/CHANGELOG.md
+++ b/src/Libraries/Microsoft.Extensions.AI/CHANGELOG.md
@@ -3,6 +3,7 @@
 ## NOT YET RELEASED
 
 - Added `FunctionInvokingChatClient` support for non-invocable tools and `TerminateOnUnknownCalls` property.
+- Added support to `FunctionInvokingChatClient` for user approval of function invocations.
 - Updated the Open Telemetry instrumentation to conform to the latest 1.37.0 draft specification of the Semantic Conventions for Generative AI systems.
 - Fixed `GetResponseAsync<T>` to only look at the contents of the last message in the response.
 
diff --git a/src/Libraries/Microsoft.Extensions.AI/ChatCompletion/FunctionInvokingChatClient.cs b/src/Libraries/Microsoft.Extensions.AI/ChatCompletion/FunctionInvokingChatClient.cs
index d503ef84630..e907078d535 100644
--- a/src/Libraries/Microsoft.Extensions.AI/ChatCompletion/FunctionInvokingChatClient.cs
+++ b/src/Libraries/Microsoft.Extensions.AI/ChatCompletion/FunctionInvokingChatClient.cs
@@ -14,10 +14,15 @@
 using Microsoft.Extensions.Logging.Abstractions;
 using Microsoft.Shared.Diagnostics;
 
+#pragma warning disable CA1508 // Avoid dead conditional code
 #pragma warning disable CA2213 // Disposable fields should be disposed
 #pragma warning disable EA0002 // Use 'System.TimeProvider' to make the code easier to test
 #pragma warning disable SA1202 // 'protected' members should come before 'private' members
 #pragma warning disable S107 // Methods should not have too many parameters
+#pragma warning disable S907 // "goto" statement should not be used
+#pragma warning disable S1659 // Multiple variables should not be declared on the same line
+#pragma warning disable S3353 // Unchanged local variables should be "const"
+#pragma warning disable IDE0031 // Use null propagation, suppressed until repo updates to C# 14
 #pragma warning disable IDE0032 // Use auto property, suppressed until repo updates to C# 14
 
 namespace Microsoft.Extensions.AI;
@@ -28,14 +33,33 @@ namespace Microsoft.Extensions.AI;
 /// </summary>
 /// <remarks>
 /// <para>
-/// When this client receives a <see cref="FunctionCallContent"/> in a chat response, it responds
-/// by calling the corresponding <see cref="AIFunction"/> defined in <see cref="ChatOptions.Tools"/>,
-/// producing a <see cref="FunctionResultContent"/> that it sends back to the inner client. This loop
-/// is repeated until there are no more function calls to make, or until another stop condition is met,
-/// such as hitting <see cref="MaximumIterationsPerRequest"/>.
+/// When this client receives a <see cref="FunctionCallContent"/> in a chat response from its inner
+/// <see cref="IChatClient"/>, it responds by invoking the corresponding <see cref="AIFunction"/> defined
+/// in <see cref="ChatOptions.Tools"/> (or in <see cref="AdditionalTools"/>), producing a <see cref="FunctionResultContent"/>
+/// that it sends back to the inner client. This loop is repeated until there are no more function calls to make, or until
+/// another stop condition is met, such as hitting <see cref="MaximumIterationsPerRequest"/>.
 /// </para>
 /// <para>
-/// The provided implementation of <see cref="IChatClient"/> is thread-safe for concurrent use so long as the
+/// If a requested function is an <see cref="AIFunctionDeclaration"/> but not an <see cref="AIFunction"/>, the
+/// <see cref="FunctionInvokingChatClient"/> will not attempt to invoke it, and instead allow that <see cref="FunctionCallContent"/>
+/// to pass back out to the caller. It is then that caller's responsibility to create the appropriate <see cref="FunctionResultContent"/>
+/// for that call and send it back as part of a subsequent request.
+/// </para>
+/// <para>
+/// Further, if a requested function is an <see cref="ApprovalRequiredAIFunction"/>, the <see cref="FunctionInvokingChatClient"/> will not
+/// attempt to invoke it directly. Instead, it will replace that <see cref="FunctionCallContent"/> with a <see cref="FunctionApprovalRequestContent"/>
+/// that wraps the <see cref="FunctionCallContent"/> and indicates that the function requires approval before it can be invoked. The caller is then
+/// responsible for responding to that approval request by sending a corresponding <see cref="FunctionApprovalResponseContent"/> in a subsequent
+/// request. The <see cref="FunctionInvokingChatClient"/> will then process that approval response and invoke the function as appropriate.
+/// </para>
+/// <para>
+/// Due to the nature of interactions with an underlying <see cref="IChatClient"/>, if any <see cref="FunctionCallContent"/> is received
+/// for a function that requires approval, all received <see cref="FunctionCallContent"/> in that same response will also require approval,
+/// even if they were not <see cref="ApprovalRequiredAIFunction"/> instances. If this is a concern, consider requesting that multiple tool call
+/// requests not be made in a single response, by setting <see cref="ChatOptions.AllowMultipleToolCalls"/> to <see langword="false"/>.
+/// </para>
+/// <para>
+/// A <see cref="FunctionInvokingChatClient"/> instance is thread-safe for concurrent use so long as the
 /// <see cref="AIFunction"/> instances employed as part of the supplied <see cref="ChatOptions"/> are also safe.
 /// The <see cref="AllowConcurrentInvocation"/> property can be used to control whether multiple function invocation
 /// requests as part of the same request are invocable concurrently, but even with that set to <see langword="false"/>
@@ -264,7 +288,6 @@ public override async Task<ChatResponse> GetResponseAsync(
         List<ChatMessage> originalMessages = [.. messages];
         messages = originalMessages;
 
-        Dictionary<string, AITool>? toolMap = null; // all available tools, indexed by name
         List<ChatMessage>? augmentedHistory = null; // the actual history of messages sent on turns other than the first
         ChatResponse? response = null; // the response from the inner client, which is possibly modified and then eventually returned
         List<ChatMessage>? responseMessages = null; // tracked list of messages, across multiple turns, to be used for the final response
@@ -273,6 +296,35 @@ public override async Task<ChatResponse> GetResponseAsync(
         bool lastIterationHadConversationId = false; // whether the last iteration's response had a ConversationId set
         int consecutiveErrorCount = 0;
 
+        (Dictionary<string, AITool>? toolMap, bool anyToolsRequireApproval) = CreateToolsMap(AdditionalTools, options?.Tools); // all available tools, indexed by name
+
+        if (HasAnyApprovalContent(originalMessages))
+        {
+            // A previous turn may have translated FunctionCallContents from the inner client into approval requests sent back to the caller,
+            // for any AIFunctions that were actually ApprovalRequiredAIFunctions. If the incoming chat messages include responses to those
+            // approval requests, we need to process them now. This entails removing these manufactured approval requests from the chat message
+            // list and replacing them with the appropriate FunctionCallContents and FunctionResultContents that would have been generated if
+            // the inner client had returned them directly.
+            (responseMessages, var notInvokedApprovals) = ProcessFunctionApprovalResponses(
+                originalMessages, !string.IsNullOrWhiteSpace(options?.ConversationId), toolMessageId: null, functionCallContentFallbackMessageId: null);
+            (IList<ChatMessage>? invokedApprovedFunctionApprovalResponses, bool shouldTerminate, consecutiveErrorCount) =
+                await InvokeApprovedFunctionApprovalResponsesAsync(notInvokedApprovals, toolMap, originalMessages, options, consecutiveErrorCount, isStreaming: false, cancellationToken);
+
+            if (invokedApprovedFunctionApprovalResponses is not null)
+            {
+                // Add any generated FRCs to the list we'll return to callers as part of the next response.
+                (responseMessages ??= []).AddRange(invokedApprovedFunctionApprovalResponses);
+            }
+
+            if (shouldTerminate)
+            {
+                return new ChatResponse(responseMessages);
+            }
+        }
+
+        // At this point, we've fully handled all approval responses that were part of the original messages,
+        // and we can now enter the main function calling loop.
+
         for (int iteration = 0; ; iteration++)
         {
             functionCallContents?.Clear();
@@ -284,19 +336,31 @@ public override async Task<ChatResponse> GetResponseAsync(
                 Throw.InvalidOperationException($"The inner {nameof(IChatClient)} returned a null {nameof(ChatResponse)}.");
             }
 
+            // Before we do any function execution, make sure that any functions that require approval have been turned into
+            // approval requests so that they don't get executed here.
+            if (anyToolsRequireApproval)
+            {
+                Debug.Assert(toolMap is not null, "anyToolsRequireApproval can only be true if there are tools");
+                response.Messages = ReplaceFunctionCallsWithApprovalRequests(response.Messages, toolMap!);
+            }
+
             // Any function call work to do? If yes, ensure we're tracking that work in functionCallContents.
             bool requiresFunctionInvocation =
                 iteration < MaximumIterationsPerRequest &&
                 CopyFunctionCalls(response.Messages, ref functionCallContents);
 
-            if (requiresFunctionInvocation)
-            {
-                toolMap ??= CreateToolsDictionary(AdditionalTools, options?.Tools);
-            }
-            else if (iteration == 0)
+            if (!requiresFunctionInvocation && iteration == 0)
             {
-                // In a common case where we make a request and there's no function calling work required,
-                // fast path out by just returning the original response.
+                // In a common case where we make an initial request and there's no function calling work required,
+                // fast path out by just returning the original response. We may already have some messages
+                // in responseMessages from processing function approval responses, and we need to ensure
+                // those are included in the final response, too.
+                if (responseMessages is { Count: > 0 })
+                {
+                    responseMessages.AddRange(response.Messages);
+                    response.Messages = responseMessages;
+                }
+
                 return response;
             }
 
@@ -364,7 +428,7 @@ public override async IAsyncEnumerable<ChatResponseUpdate> GetStreamingResponseA
         List<ChatMessage> originalMessages = [.. messages];
         messages = originalMessages;
 
-        Dictionary<string, AITool>? toolMap = null; // all available tools, indexed by name
+        ApprovalRequiredAIFunction[]? approvalRequiredFunctions = null; // available tools that require approval
         List<ChatMessage>? augmentedHistory = null; // the actual history of messages sent on turns other than the first
         List<FunctionCallContent>? functionCallContents = null; // function call contents that need responding to in the current turn
         List<ChatMessage>? responseMessages = null; // tracked list of messages, across multiple turns, to be used in fallback cases to reconstitute history
@@ -372,11 +436,69 @@ public override async IAsyncEnumerable<ChatResponseUpdate> GetStreamingResponseA
         List<ChatResponseUpdate> updates = []; // updates from the current response
         int consecutiveErrorCount = 0;
 
+        (Dictionary<string, AITool>? toolMap, bool anyToolsRequireApproval) = CreateToolsMap(AdditionalTools, options?.Tools); // all available tools, indexed by name
+
+        // This is a synthetic ID since we're generating the tool messages instead of getting them from
+        // the underlying provider. When emitting the streamed chunks, it's perfectly valid for us to
+        // use the same message ID for all of them within a given iteration, as this is a single logical
+        // message with multiple content items. We could also use different message IDs per tool content,
+        // but there's no benefit to doing so.
+        string toolMessageId = Guid.NewGuid().ToString("N");
+
+        if (HasAnyApprovalContent(originalMessages))
+        {
+            // We also need a synthetic ID for the function call content for approved function calls
+            // where we don't know what the original message id of the function call was.
+            string functionCallContentFallbackMessageId = Guid.NewGuid().ToString("N");
+
+            // A previous turn may have translated FunctionCallContents from the inner client into approval requests sent back to the caller,
+            // for any AIFunctions that were actually ApprovalRequiredAIFunctions. If the incoming chat messages include responses to those
+            // approval requests, we need to process them now. This entails removing these manufactured approval requests from the chat message
+            // list and replacing them with the appropriate FunctionCallContents and FunctionResultContents that would have been generated if
+            // the inner client had returned them directly.
+            var (preDownstreamCallHistory, notInvokedApprovals) = ProcessFunctionApprovalResponses(
+                originalMessages, !string.IsNullOrWhiteSpace(options?.ConversationId), toolMessageId, functionCallContentFallbackMessageId);
+            if (preDownstreamCallHistory is not null)
+            {
+                foreach (var message in preDownstreamCallHistory)
+                {
+                    yield return ConvertToolResultMessageToUpdate(message, options?.ConversationId, message.MessageId);
+                    Activity.Current = activity; // workaround for https://github.com/dotnet/runtime/issues/47802
+                }
+            }
+
+            // Invoke approved approval responses, which generates some additional FRC wrapped in ChatMessage.
+            (IList<ChatMessage>? invokedApprovedFunctionApprovalResponses, bool shouldTerminate, consecutiveErrorCount) =
+                await InvokeApprovedFunctionApprovalResponsesAsync(notInvokedApprovals, toolMap, originalMessages, options, consecutiveErrorCount, isStreaming: true, cancellationToken);
+
+            if (invokedApprovedFunctionApprovalResponses is not null)
+            {
+                foreach (var message in invokedApprovedFunctionApprovalResponses)
+                {
+                    message.MessageId = toolMessageId;
+                    yield return ConvertToolResultMessageToUpdate(message, options?.ConversationId, message.MessageId);
+                    Activity.Current = activity; // workaround for https://github.com/dotnet/runtime/issues/47802
+                }
+
+                if (shouldTerminate)
+                {
+                    yield break;
+                }
+            }
+        }
+
+        // At this point, we've fully handled all approval responses that were part of the original messages,
+        // and we can now enter the main function calling loop.
+
         for (int iteration = 0; ; iteration++)
         {
             updates.Clear();
             functionCallContents?.Clear();
 
+            bool hasApprovalRequiringFcc = false;
+            int lastApprovalCheckedFCCIndex = 0;
+            int lastYieldedUpdateIndex = 0;
+
             await foreach (var update in base.GetStreamingResponseAsync(messages, options, cancellationToken))
             {
                 if (update is null)
@@ -401,18 +523,80 @@ public override async IAsyncEnumerable<ChatResponseUpdate> GetStreamingResponseA
                     }
                 }
 
-                yield return update;
-                Activity.Current = activity; // workaround for https://github.com/dotnet/runtime/issues/47802
+                // We're streaming updates back to the caller. However, approvals requires extra handling. We should not yield any
+                // FunctionCallContents back to the caller if approvals might be required, because if any actually are, we need to convert
+                // all FunctionCallContents into approval requests, even those that don't require approval (we otherwise don't have a way
+                // to track the FCCs to a later turn, in particular when the conversation history is managed by the service / inner client).
+                // So, if there are no functions that need approval, we can yield updates with FCCs as they arrive. But if any FCC _might_
+                // require approval (which just means that any AIFunction we can possibly invoke requires approval), then we need to hold off
+                // on yielding any FCCs until we know whether any of them actually require approval, which is either at the end of the stream
+                // or the first time we get an FCC that requires approval. At that point, we can yield all of the updates buffered thus far
+                // and anything further, replacing FCCs with approval if any required it, or yielding them as is.
+                if (anyToolsRequireApproval && approvalRequiredFunctions is null && functionCallContents is { Count: > 0 })
+                {
+                    approvalRequiredFunctions =
+                        (options?.Tools ?? Enumerable.Empty<AITool>())
+                        .Concat(AdditionalTools ?? Enumerable.Empty<AITool>())
+                        .OfType<ApprovalRequiredAIFunction>()
+                        .ToArray();
+                }
+
+                if (approvalRequiredFunctions is not { Length: > 0 })
+                {
+                    // If there are no function calls to make yet, or if none of the functions require approval at all,
+                    // we can yield the update as-is.
+                    lastYieldedUpdateIndex++;
+                    yield return update;
+                    Activity.Current = activity; // workaround for https://github.com/dotnet/runtime/issues/47802
+
+                    continue;
+                }
+
+                // There are function calls to make, some of which _may_ require approval.
+                Debug.Assert(functionCallContents is { Count: > 0 }, "Expected to have function call contents to check for approval requiring functions.");
+                Debug.Assert(approvalRequiredFunctions is { Length: > 0 }, "Expected to have approval requiring functions to check against function call contents.");
+
+                // Check if any of the function call contents in this update requires approval.
+                (hasApprovalRequiringFcc, lastApprovalCheckedFCCIndex) = CheckForApprovalRequiringFCC(
+                    functionCallContents, approvalRequiredFunctions!, hasApprovalRequiringFcc, lastApprovalCheckedFCCIndex);
+                if (hasApprovalRequiringFcc)
+                {
+                    // If we've encountered a function call content that requires approval,
+                    // we need to ask for approval for all functions, since we cannot mix and match.
+                    // Convert all function call contents into approval requests from the last yielded update index
+                    // and yield all those updates.
+                    for (; lastYieldedUpdateIndex < updates.Count; lastYieldedUpdateIndex++)
+                    {
+                        var updateToYield = updates[lastYieldedUpdateIndex];
+                        if (TryReplaceFunctionCallsWithApprovalRequests(updateToYield.Contents, out var updatedContents))
+                        {
+                            updateToYield.Contents = updatedContents;
+                        }
+
+                        yield return updateToYield;
+                        Activity.Current = activity; // workaround for https://github.com/dotnet/runtime/issues/47802
+                    }
+
+                    continue;
+                }
+
+                // We don't have any approval requiring function calls yet, but we may receive some in future
+                // so we cannot yield the updates yet. We'll just keep them in the updates list for later.
+                // We will yield the updates as soon as we receive a function call content that requires approval
+                // or when we reach the end of the updates stream.
             }
 
             // If there's nothing more to do, break out of the loop and allow the handling at the
             // end to configure the response with aggregated data from previous requests.
             if (iteration >= MaximumIterationsPerRequest ||
-                ShouldTerminateLoopBasedOnHandleableFunctions(functionCallContents, toolMap ??= CreateToolsDictionary(AdditionalTools, options?.Tools)))
+                hasApprovalRequiringFcc ||
+                ShouldTerminateLoopBasedOnHandleableFunctions(functionCallContents, toolMap))
             {
                 break;
             }
 
+            // We need to invoke functions.
+
             // Reconstitute a response from the response updates.
             var response = updates.ToChatResponse();
             (responseMessages ??= []).AddRange(response.Messages);
@@ -425,31 +609,11 @@ public override async IAsyncEnumerable<ChatResponseUpdate> GetStreamingResponseA
             responseMessages.AddRange(modeAndMessages.MessagesAdded);
             consecutiveErrorCount = modeAndMessages.NewConsecutiveErrorCount;
 
-            // This is a synthetic ID since we're generating the tool messages instead of getting them from
-            // the underlying provider. When emitting the streamed chunks, it's perfectly valid for us to
-            // use the same message ID for all of them within a given iteration, as this is a single logical
-            // message with multiple content items. We could also use different message IDs per tool content,
-            // but there's no benefit to doing so.
-            string toolResponseId = Guid.NewGuid().ToString("N");
-
             // Stream any generated function results. This mirrors what's done for GetResponseAsync, where the returned messages
             // includes all activities, including generated function results.
             foreach (var message in modeAndMessages.MessagesAdded)
             {
-                var toolResultUpdate = new ChatResponseUpdate
-                {
-                    AdditionalProperties = message.AdditionalProperties,
-                    AuthorName = message.AuthorName,
-                    ConversationId = response.ConversationId,
-                    CreatedAt = DateTimeOffset.UtcNow,
-                    Contents = message.Contents,
-                    RawRepresentation = message.RawRepresentation,
-                    ResponseId = toolResponseId,
-                    MessageId = toolResponseId, // See above for why this can be the same as ResponseId
-                    Role = message.Role,
-                };
-
-                yield return toolResultUpdate;
+                yield return ConvertToolResultMessageToUpdate(message, response.ConversationId, toolMessageId);
                 Activity.Current = activity; // workaround for https://github.com/dotnet/runtime/issues/47802
             }
 
@@ -464,6 +628,20 @@ public override async IAsyncEnumerable<ChatResponseUpdate> GetStreamingResponseA
         AddUsageTags(activity, totalUsage);
     }
 
+    private static ChatResponseUpdate ConvertToolResultMessageToUpdate(ChatMessage message, string? conversationId, string? messageId) =>
+        new()
+        {
+            AdditionalProperties = message.AdditionalProperties,
+            AuthorName = message.AuthorName,
+            ConversationId = conversationId,
+            CreatedAt = DateTimeOffset.UtcNow,
+            Contents = message.Contents,
+            RawRepresentation = message.RawRepresentation,
+            ResponseId = messageId,
+            MessageId = messageId,
+            Role = message.Role,
+        };
+
     /// <summary>Adds tags to <paramref name="activity"/> for usage details in <paramref name="usage"/>.</summary>
     private static void AddUsageTags(Activity? activity, UsageDetails? usage)
     {
@@ -543,31 +721,39 @@ private static void FixupHistories(
         messages = augmentedHistory;
     }
 
-    /// <summary>Creates a dictionary mapping tool names to the corresponding tools.</summary>
+    /// <summary>Creates a mapping from tool names to the corresponding tools.</summary>
     /// <param name="toolLists">
     /// The lists of tools to combine into a single dictionary. Tools from later lists are preferred
     /// over tools from earlier lists if they have the same name.
     /// </param>
-    private static Dictionary<string, AITool>? CreateToolsDictionary(params ReadOnlySpan<IList<AITool>?> toolLists)
+    private static (Dictionary<string, AITool>? ToolMap, bool AnyRequireApproval) CreateToolsMap(params ReadOnlySpan<IList<AITool>?> toolLists)
     {
-        Dictionary<string, AITool>? tools = null;
+        Dictionary<string, AITool>? map = null;
+        bool anyRequireApproval = false;
 
         foreach (var toolList in toolLists)
         {
             if (toolList?.Count is int count && count > 0)
             {
-                tools ??= new(StringComparer.Ordinal);
+                map ??= new(StringComparer.Ordinal);
                 for (int i = 0; i < count; i++)
                 {
                     AITool tool = toolList[i];
-                    tools[tool.Name] = tool;
+                    anyRequireApproval |= tool is ApprovalRequiredAIFunction;
+                    map[tool.Name] = tool;
                 }
             }
         }
 
-        return tools;
+        return (map, anyRequireApproval);
     }
 
+    /// <summary>
+    /// Gets whether <paramref name="messages"/> contains any <see cref="FunctionApprovalRequestContent"/> or <see cref="FunctionApprovalResponseContent"/> instances.
+    /// </summary>
+    private static bool HasAnyApprovalContent(List<ChatMessage> messages) =>
+        messages.Any(static m => m.Contents.Any(static c => c is FunctionApprovalRequestContent or FunctionApprovalResponseContent));
+
     /// <summary>Copies any <see cref="FunctionCallContent"/> from <paramref name="messages"/> to <paramref name="functionCalls"/>.</summary>
     private static bool CopyFunctionCalls(
         IList<ChatMessage> messages, [NotNullWhen(true)] ref List<FunctionCallContent>? functionCalls)
@@ -758,7 +944,6 @@ select ProcessFunctionCallAsync(
         }
     }
 
-#pragma warning disable CA1851 // Possible multiple enumerations of 'IEnumerable' collection
     /// <summary>
     /// Updates the consecutive error count, and throws an exception if the count exceeds the maximum.
     /// </summary>
@@ -767,24 +952,23 @@ select ProcessFunctionCallAsync(
     /// <exception cref="AggregateException">Thrown if the maximum consecutive error count is exceeded.</exception>
     private void UpdateConsecutiveErrorCountOrThrow(IList<ChatMessage> added, ref int consecutiveErrorCount)
     {
-        var allExceptions = added.SelectMany(m => m.Contents.OfType<FunctionResultContent>())
-            .Select(frc => frc.Exception!)
-            .Where(e => e is not null);
-
-        if (allExceptions.Any())
+        if (added.Any(static m => m.Contents.Any(static c => c is FunctionResultContent { Exception: not null })))
         {
             consecutiveErrorCount++;
             if (consecutiveErrorCount > MaximumConsecutiveErrorsPerRequest)
             {
-                var allExceptionsArray = allExceptions.ToArray();
+                var allExceptionsArray = added
+                    .SelectMany(m => m.Contents.OfType<FunctionResultContent>())
+                    .Select(frc => frc.Exception!)
+                    .Where(e => e is not null)
+                    .ToArray();
+
                 if (allExceptionsArray.Length == 1)
                 {
                     ExceptionDispatchInfo.Capture(allExceptionsArray[0]).Throw();
                 }
-                else
-                {
-                    throw new AggregateException(allExceptionsArray);
-                }
+
+                throw new AggregateException(allExceptionsArray);
             }
         }
         else
@@ -792,14 +976,13 @@ private void UpdateConsecutiveErrorCountOrThrow(IList<ChatMessage> added, ref in
             consecutiveErrorCount = 0;
         }
     }
-#pragma warning restore CA1851
 
     /// <summary>
     /// Throws an exception if <see cref="CreateResponseMessages"/> doesn't create any messages.
     /// </summary>
     private void ThrowIfNoFunctionResultsAdded(IList<ChatMessage>? messages)
     {
-        if (messages is null || messages.Count == 0)
+        if (messages is not { Count: > 0 })
         {
             Throw.InvalidOperationException($"{GetType().Name}.{nameof(CreateResponseMessages)} returned null or an empty collection of messages.");
         }
@@ -1011,6 +1194,384 @@ FunctionResultContent CreateFunctionResultContent(FunctionInvocationResult resul
             context.Function.InvokeAsync(context.Arguments, cancellationToken);
     }
 
+    /// <summary>
+    /// 1. Remove all <see cref="FunctionApprovalRequestContent"/> and <see cref="FunctionApprovalResponseContent"/> from the <paramref name="originalMessages"/>.
+    /// 2. Recreate <see cref="FunctionCallContent"/> for any <see cref="FunctionApprovalResponseContent"/> that haven't been executed yet.
+    /// 3. Genreate failed <see cref="FunctionResultContent"/> for any rejected <see cref="FunctionApprovalResponseContent"/>.
+    /// 4. add all the new content items to <paramref name="originalMessages"/> and return them as the pre-invocation history.
+    /// </summary>
+    private static (List<ChatMessage>? preDownstreamCallHistory, List<ApprovalResultWithRequestMessage>? approvals) ProcessFunctionApprovalResponses(
+        List<ChatMessage> originalMessages, bool hasConversationId, string? toolMessageId, string? functionCallContentFallbackMessageId)
+    {
+        // Extract any approval responses where we need to execute or reject the function calls.
+        // The original messages are also modified to remove all approval requests and responses.
+        var notInvokedResponses = ExtractAndRemoveApprovalRequestsAndResponses(originalMessages);
+
+        // Wrap the function call content in message(s).
+        ICollection<ChatMessage>? allPreDownstreamCallMessages = ConvertToFunctionCallContentMessages(
+            [.. notInvokedResponses.rejections ?? Enumerable.Empty<ApprovalResultWithRequestMessage>(), .. notInvokedResponses.approvals ?? Enumerable.Empty<ApprovalResultWithRequestMessage>()],
+            functionCallContentFallbackMessageId);
+
+        // Generate failed function result contents for any rejected requests and wrap it in a message.
+        List<AIContent>? rejectedFunctionCallResults = GenerateRejectedFunctionResults(notInvokedResponses.rejections);
+        ChatMessage? rejectedPreDownstreamCallResultsMessage = rejectedFunctionCallResults is not null ?
+            new ChatMessage(ChatRole.Tool, rejectedFunctionCallResults) { MessageId = toolMessageId } :
+            null;
+
+        // Add all the FCC that we generated to the pre-downstream-call history so that they can be returned to the caller as part of the next response.
+        // Also, if we are not dealing with a service thread (i.e. we don't have a conversation ID), add them
+        // into the original messages list so that they are passed to the inner client and can be used to generate a result.
+        List<ChatMessage>? preDownstreamCallHistory = null;
+        if (allPreDownstreamCallMessages is not null)
+        {
+            preDownstreamCallHistory = [.. allPreDownstreamCallMessages];
+            if (!hasConversationId)
+            {
+                originalMessages.AddRange(preDownstreamCallHistory);
+            }
+        }
+
+        // Add all the FRC that we generated to the pre-downstream-call history so that they can be returned to the caller as part of the next response.
+        // Also, add them into the original messages list so that they are passed to the inner client and can be used to generate a result.
+        if (rejectedPreDownstreamCallResultsMessage is not null)
+        {
+            (preDownstreamCallHistory ??= []).Add(rejectedPreDownstreamCallResultsMessage);
+            originalMessages.Add(rejectedPreDownstreamCallResultsMessage);
+        }
+
+        return (preDownstreamCallHistory, notInvokedResponses.approvals);
+    }
+
+    /// <summary>
+    /// This method extracts the approval requests and responses from the provided list of messages,
+    /// validates them, filters them to ones that require execution, and splits them into approved and rejected.
+    /// </summary>
+    /// <remarks>
+    /// We return the messages containing the approval requests since these are the same messages that originally contained the FunctionCallContent from the downstream service.
+    /// We can then use the metadata from these messages when we re-create the FunctionCallContent messages/updates to return to the caller. This way, when we finally do return
+    /// the FuncionCallContent to users it's part of a message/update that contains the same metadata as originally returned to the downstream service.
+    /// </remarks>
+    private static (List<ApprovalResultWithRequestMessage>? approvals, List<ApprovalResultWithRequestMessage>? rejections) ExtractAndRemoveApprovalRequestsAndResponses(
+        List<ChatMessage> messages)
+    {
+        Dictionary<string, ChatMessage>? allApprovalRequestsMessages = null;
+        List<FunctionApprovalResponseContent>? allApprovalResponses = null;
+        HashSet<string>? approvalRequestCallIds = null;
+        HashSet<string>? functionResultCallIds = null;
+
+        // 1st iteration, over all messages and content:
+        // - Build a list of all function call ids that are already executed.
+        // - Build a list of all function approval requests and responses.
+        // - Build a list of the content we want to keep (everything except approval requests and responses) and create a new list of messages for those.
+        // - Validate that we have an approval response for each approval request.
+        bool anyRemoved = false;
+        int i = 0;
+        for (; i < messages.Count; i++)
+        {
+            var message = messages[i];
+
+            List<AIContent>? keptContents = null;
+
+            // Examine all content to populate our various collections.
+            for (int j = 0; j < message.Contents.Count; j++)
+            {
+                var content = message.Contents[j];
+                switch (content)
+                {
+                    case FunctionApprovalRequestContent farc:
+                        // Validation: Capture each call id for each approval request to ensure later we have a matching response.
+                        _ = (approvalRequestCallIds ??= []).Add(farc.FunctionCall.CallId);
+                        (allApprovalRequestsMessages ??= []).Add(farc.Id, message);
+                        break;
+
+                    case FunctionApprovalResponseContent farc:
+                        // Validation: Remove the call id for each approval response, to check it off the list of requests we need responses for.
+                        _ = approvalRequestCallIds?.Remove(farc.FunctionCall.CallId);
+                        (allApprovalResponses ??= []).Add(farc);
+                        break;
+
+                    case FunctionResultContent frc:
+                        // Maintain a list of function calls that have already been invoked to avoid invoking them twice.
+                        _ = (functionResultCallIds ??= []).Add(frc.CallId);
+                        goto default;
+
+                    default:
+                        // Content to keep.
+                        (keptContents ??= []).Add(content);
+                        break;
+                }
+            }
+
+            // If any contents were filtered out, we need to either remove the message entirely (if no contents remain) or create a new message with the filtered contents.
+            if (keptContents?.Count != message.Contents.Count)
+            {
+                if (keptContents is { Count: > 0 })
+                {
+                    // Create a new replacement message to store the filtered contents.
+                    var newMessage = message.Clone();
+                    newMessage.Contents = keptContents;
+                    messages[i] = newMessage;
+                }
+                else
+                {
+                    // Remove the message entirely since it has no contents left. Rather than doing an O(N) removal, which could possibly
+                    // result in an O(N^2) overall operation, we mark the message as null and then do a single pass removal of all nulls after the loop.
+                    anyRemoved = true;
+                    messages[i] = null!;
+                }
+            }
+        }
+
+        // Clean up any messages that were marked for removal during the iteration.
+        if (anyRemoved)
+        {
+            _ = messages.RemoveAll(static m => m is null);
+        }
+
+        // Validation: If we got an approval for each request, we should have no call ids left.
+        if (approvalRequestCallIds is { Count: > 0 })
+        {
+            Throw.InvalidOperationException(
+                $"FunctionApprovalRequestContent found with FunctionCall.CallId(s) '{string.Join(", ", approvalRequestCallIds)}' that have no matching FunctionApprovalResponseContent.");
+        }
+
+        // 2nd iteration, over all approval responses:
+        // - Filter out any approval responses that already have a matching function result (i.e. already executed).
+        // - Find the matching function approval request for any response (where available).
+        // - Split the approval responses into two lists: approved and rejected, with their request messages (where available).
+        List<ApprovalResultWithRequestMessage>? approvedFunctionCalls = null, rejectedFunctionCalls = null;
+        if (allApprovalResponses is { Count: > 0 })
+        {
+            foreach (var approvalResponse in allApprovalResponses)
+            {
+                // Skip any approval responses that have already been processed.
+                if (functionResultCallIds?.Contains(approvalResponse.FunctionCall.CallId) is true)
+                {
+                    continue;
+                }
+
+                // Split the responses into approved and rejected.
+                ref List<ApprovalResultWithRequestMessage>? targetList = ref approvalResponse.Approved ? ref approvedFunctionCalls : ref rejectedFunctionCalls;
+
+                ChatMessage? requestMessage = null;
+                _ = allApprovalRequestsMessages?.TryGetValue(approvalResponse.FunctionCall.CallId, out requestMessage);
+
+                (targetList ??= []).Add(new() { Response = approvalResponse, RequestMessage = requestMessage });
+            }
+        }
+
+        return (approvedFunctionCalls, rejectedFunctionCalls);
+    }
+
+    /// <summary>
+    /// If we have any rejected approval responses, we need to generate failed function results for them.
+    /// </summary>
+    /// <param name="rejections">Any rejected approval responses.</param>
+    /// <returns>The <see cref="AIContent"/> for the rejected function calls.</returns>
+    private static List<AIContent>? GenerateRejectedFunctionResults(List<ApprovalResultWithRequestMessage>? rejections) =>
+        rejections is { Count: > 0 } ?
+            rejections.ConvertAll(static m => (AIContent)new FunctionResultContent(m.Response.FunctionCall.CallId, "Error: Tool call invocation was rejected by user.")) :
+            null;
+
+    /// <summary>
+    /// Extracts the <see cref="FunctionCallContent"/> from the provided <see cref="FunctionApprovalResponseContent"/> to recreate the original function call messages.
+    /// The output messages tries to mimic the original messages that contained the <see cref="FunctionCallContent"/>, e.g. if the <see cref="FunctionCallContent"/>
+    /// had been split into separate messages, this method will recreate similarly split messages, each with their own <see cref="FunctionCallContent"/>.
+    /// </summary>
+    private static ICollection<ChatMessage>? ConvertToFunctionCallContentMessages(
+        List<ApprovalResultWithRequestMessage>? resultWithRequestMessages, string? fallbackMessageId)
+    {
+        if (resultWithRequestMessages is not null)
+        {
+            ChatMessage? currentMessage = null;
+            Dictionary<string, ChatMessage>? messagesById = null;
+
+            foreach (var resultWithRequestMessage in resultWithRequestMessages)
+            {
+                // Don't need to create a dictionary if we already have one or if it's the first iteration.
+                if (messagesById is null && currentMessage is not null
+
+                    // Everywhere we have no RequestMessage we use the fallbackMessageId, so in this case there is only one message.
+                    && !(resultWithRequestMessage.RequestMessage is null && currentMessage.MessageId == fallbackMessageId)
+
+                    // Where we do have a RequestMessage, we can check if its message id differs from the current one.
+                    && (resultWithRequestMessage.RequestMessage is not null && currentMessage.MessageId != resultWithRequestMessage.RequestMessage.MessageId))
+                {
+                    // The majority of the time, all FCC would be part of a single message, so no need to create a dictionary for this case.
+                    // If we are dealing with multiple messages though, we need to keep track of them by their message ID.
+                    messagesById = [];
+                    messagesById[currentMessage.MessageId ?? string.Empty] = currentMessage;
+                }
+
+                _ = messagesById?.TryGetValue(resultWithRequestMessage.RequestMessage?.MessageId ?? string.Empty, out currentMessage);
+
+                if (currentMessage is null)
+                {
+                    currentMessage = ConvertToFunctionCallContentMessage(resultWithRequestMessage, fallbackMessageId);
+                }
+                else
+                {
+                    currentMessage.Contents.Add(resultWithRequestMessage.Response.FunctionCall);
+                }
+
+                if (messagesById is not null)
+                {
+                    messagesById[currentMessage.MessageId ?? string.Empty] = currentMessage;
+                }
+            }
+
+            if (messagesById?.Values is ICollection<ChatMessage> cm)
+            {
+                return cm;
+            }
+
+            if (currentMessage is not null)
+            {
+                return [currentMessage];
+            }
+        }
+
+        return null;
+    }
+
+    /// <summary>
+    /// Takes the <see cref="FunctionCallContent"/> from the <paramref name="resultWithRequestMessage"/> and wraps it in a <see cref="ChatMessage"/>
+    /// using the same message id that the <see cref="FunctionCallContent"/> was originally returned with from the downstream <see cref="IChatClient"/>.
+    /// </summary>
+    private static ChatMessage ConvertToFunctionCallContentMessage(ApprovalResultWithRequestMessage resultWithRequestMessage, string? fallbackMessageId)
+    {
+        ChatMessage functionCallMessage = resultWithRequestMessage.RequestMessage?.Clone() ?? new() { Role = ChatRole.Assistant };
+        functionCallMessage.Contents = [resultWithRequestMessage.Response.FunctionCall];
+        functionCallMessage.MessageId ??= fallbackMessageId;
+        return functionCallMessage;
+    }
+
+    /// <summary>
+    /// Check if any of the provided <paramref name="functionCallContents"/> require approval.
+    /// Supports checking from a provided index up to the end of the list, to allow efficient incremental checking
+    /// when streaming.
+    /// </summary>
+    private static (bool hasApprovalRequiringFcc, int lastApprovalCheckedFCCIndex) CheckForApprovalRequiringFCC(
+        List<FunctionCallContent>? functionCallContents,
+        ApprovalRequiredAIFunction[] approvalRequiredFunctions,
+        bool hasApprovalRequiringFcc,
+        int lastApprovalCheckedFCCIndex)
+    {
+        // If we already found an approval requiring FCC, we can skip checking the rest.
+        if (hasApprovalRequiringFcc)
+        {
+            Debug.Assert(functionCallContents is not null, "functionCallContents must not be null here, since we have already encountered approval requiring functionCallContents");
+            return (true, functionCallContents!.Count);
+        }
+
+        if (functionCallContents is not null)
+        {
+            for (; lastApprovalCheckedFCCIndex < functionCallContents.Count; lastApprovalCheckedFCCIndex++)
+            {
+                var fcc = functionCallContents![lastApprovalCheckedFCCIndex];
+                foreach (var arf in approvalRequiredFunctions)
+                {
+                    if (arf.Name == fcc.Name)
+                    {
+                        hasApprovalRequiringFcc = true;
+                        break;
+                    }
+                }
+            }
+        }
+
+        return (hasApprovalRequiringFcc, lastApprovalCheckedFCCIndex);
+    }
+
+    /// <summary>
+    /// Replaces all <see cref="FunctionCallContent"/> with <see cref="FunctionApprovalRequestContent"/> and ouputs a new list if any of them were replaced.
+    /// </summary>
+    /// <returns>true if any <see cref="FunctionCallContent"/> was replaced, false otherwise.</returns>
+    private static bool TryReplaceFunctionCallsWithApprovalRequests(IList<AIContent> content, out List<AIContent>? updatedContent)
+    {
+        updatedContent = null;
+
+        if (content is { Count: > 0 })
+        {
+            for (int i = 0; i < content.Count; i++)
+            {
+                if (content[i] is FunctionCallContent fcc)
+                {
+                    updatedContent ??= [.. content]; // Clone the list if we haven't already
+                    updatedContent[i] = new FunctionApprovalRequestContent(fcc.CallId, fcc);
+                }
+            }
+        }
+
+        return updatedContent is not null;
+    }
+
+    /// <summary>
+    /// Replaces all <see cref="FunctionCallContent"/> from <paramref name="messages"/> with <see cref="FunctionApprovalRequestContent"/>
+    /// if any one of them requires approval.
+    /// </summary>
+    private static IList<ChatMessage> ReplaceFunctionCallsWithApprovalRequests(
+        IList<ChatMessage> messages,
+        Dictionary<string, AITool> toolMap)
+    {
+        var outputMessages = messages;
+
+        bool anyApprovalRequired = false;
+        List<(int, int)>? allFunctionCallContentIndices = null;
+
+        // Build a list of the indices of all FunctionCallContent items.
+        // Also check if any of them require approval.
+        for (int i = 0; i < messages.Count; i++)
+        {
+            var content = messages[i].Contents;
+            for (int j = 0; j < content.Count; j++)
+            {
+                if (content[j] is FunctionCallContent functionCall)
+                {
+                    (allFunctionCallContentIndices ??= []).Add((i, j));
+
+                    if (!anyApprovalRequired)
+                    {
+                        foreach (var t in toolMap)
+                        {
+                            if (t.Value is ApprovalRequiredAIFunction araf && araf.Name == functionCall.Name)
+                            {
+                                anyApprovalRequired = true;
+                                break;
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        // If any function calls were found, and any of them required approval, we should replace all of them with approval requests.
+        // This is because we do not have a way to deal with cases where some function calls require approval and others do not, so we just replace all of them.
+        if (anyApprovalRequired)
+        {
+            Debug.Assert(allFunctionCallContentIndices is not null, "We have already encountered function call contents that require approval.");
+
+            // Clone the list so, we don't mutate the input.
+            outputMessages = [.. messages];
+            int lastMessageIndex = -1;
+
+            foreach (var (messageIndex, contentIndex) in allFunctionCallContentIndices!)
+            {
+                // Clone the message if we didn't already clone it in a previous iteration.
+                var message = lastMessageIndex != messageIndex ? outputMessages[messageIndex].Clone() : outputMessages[messageIndex];
+                message.Contents = [.. message.Contents];
+
+                var functionCall = (FunctionCallContent)message.Contents[contentIndex];
+                message.Contents[contentIndex] = new FunctionApprovalRequestContent(functionCall.CallId, functionCall);
+                outputMessages[messageIndex] = message;
+
+                lastMessageIndex = messageIndex;
+            }
+        }
+
+        return outputMessages;
+    }
+
     private static TimeSpan GetElapsedTime(long startingTimestamp) =>
 #if NET
         Stopwatch.GetElapsedTime(startingTimestamp);
@@ -1018,6 +1579,33 @@ private static TimeSpan GetElapsedTime(long startingTimestamp) =>
         new((long)((Stopwatch.GetTimestamp() - startingTimestamp) * ((double)TimeSpan.TicksPerSecond / Stopwatch.Frequency)));
 #endif
 
+    /// <summary>
+    /// Execute the provided <see cref="FunctionApprovalResponseContent"/> and return the resulting <see cref="FunctionCallContent"/>
+    /// wrapped in <see cref="ChatMessage"/> objects.
+    /// </summary>
+    private async Task<(IList<ChatMessage>? FunctionResultContentMessages, bool ShouldTerminate, int ConsecutiveErrorCount)> InvokeApprovedFunctionApprovalResponsesAsync(
+        List<ApprovalResultWithRequestMessage>? notInvokedApprovals,
+        Dictionary<string, AITool>? toolMap,
+        List<ChatMessage> originalMessages,
+        ChatOptions? options,
+        int consecutiveErrorCount,
+        bool isStreaming,
+        CancellationToken cancellationToken)
+    {
+        // Check if there are any function calls to do for any approved functions and execute them.
+        if (notInvokedApprovals is { Count: > 0 })
+        {
+            // The FRC that is generated here is already added to originalMessages by ProcessFunctionCallsAsync.
+            var modeAndMessages = await ProcessFunctionCallsAsync(
+                originalMessages, options, toolMap, notInvokedApprovals.Select(x => x.Response.FunctionCall).ToList(), 0, consecutiveErrorCount, isStreaming, cancellationToken);
+            consecutiveErrorCount = modeAndMessages.NewConsecutiveErrorCount;
+
+            return (modeAndMessages.MessagesAdded, modeAndMessages.ShouldTerminate, consecutiveErrorCount);
+        }
+
+        return (null, false, consecutiveErrorCount);
+    }
+
     [LoggerMessage(LogLevel.Debug, "Invoking {MethodName}.", SkipEnabledCheck = true)]
     private partial void LogInvoking(string methodName);
 
@@ -1084,4 +1672,10 @@ public enum FunctionInvocationStatus
         /// <summary>The function call failed with an exception.</summary>
         Exception,
     }
+
+    private struct ApprovalResultWithRequestMessage
+    {
+        public FunctionApprovalResponseContent Response { get; set; }
+        public ChatMessage? RequestMessage { get; set; }
+    }
 }
diff --git a/src/Libraries/Microsoft.Extensions.AI/Microsoft.Extensions.AI.csproj b/src/Libraries/Microsoft.Extensions.AI/Microsoft.Extensions.AI.csproj
index fe431ca21e5..0d77680cbc4 100644
--- a/src/Libraries/Microsoft.Extensions.AI/Microsoft.Extensions.AI.csproj
+++ b/src/Libraries/Microsoft.Extensions.AI/Microsoft.Extensions.AI.csproj
@@ -14,7 +14,7 @@
 
   <PropertyGroup>
     <TargetFrameworks>$(TargetFrameworks);netstandard2.0</TargetFrameworks>
-    <NoWarn>$(NoWarn);CA2227;CA1034;SA1316;S1067;S1121;S1994;S3253</NoWarn>
+    <NoWarn>$(NoWarn);CA2227;CA1034;SA1316;S1067;S1121;S1994;S3253;MEAI001</NoWarn>
 
     <!-- CA2007 requires use of ConfigureAwait. While in general we strive to use ConfigureAwait in all our libraries,
          the exemption is when user code that might care about SynchronizationContext is invoked as part of operation.
diff --git a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/AssertExtensions.cs b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/AssertExtensions.cs
index 6361fe7817e..546b93a7f20 100644
--- a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/AssertExtensions.cs
+++ b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/AssertExtensions.cs
@@ -12,6 +12,44 @@ namespace Microsoft.Extensions.AI;
 
 internal static class AssertExtensions
 {
+    /// <summary>
+    /// Asserts that the two message lists are equal.
+    /// </summary>
+    public static void EqualMessageLists(List<ChatMessage> expectedMessages, List<ChatMessage> actualMessages)
+    {
+        Assert.Equal(expectedMessages.Count, actualMessages.Count);
+        for (int i = 0; i < expectedMessages.Count; i++)
+        {
+            var expectedMessage = expectedMessages[i];
+            var chatMessage = actualMessages[i];
+
+            Assert.Equal(expectedMessage.Role, chatMessage.Role);
+            Assert.Equal(expectedMessage.Text, chatMessage.Text);
+            Assert.Equal(expectedMessage.GetType(), chatMessage.GetType());
+
+            Assert.Equal(expectedMessage.Contents.Count, chatMessage.Contents.Count);
+            for (int j = 0; j < expectedMessage.Contents.Count; j++)
+            {
+                var expectedItem = expectedMessage.Contents[j];
+                var chatItem = chatMessage.Contents[j];
+
+                Assert.Equal(expectedItem.GetType(), chatItem.GetType());
+                Assert.Equal(expectedItem.ToString(), chatItem.ToString());
+                if (expectedItem is FunctionCallContent expectedFunctionCall)
+                {
+                    var chatFunctionCall = (FunctionCallContent)chatItem;
+                    Assert.Equal(expectedFunctionCall.Name, chatFunctionCall.Name);
+                    AssertExtensions.EqualFunctionCallParameters(expectedFunctionCall.Arguments, chatFunctionCall.Arguments);
+                }
+                else if (expectedItem is FunctionResultContent expectedFunctionResult)
+                {
+                    var chatFunctionResult = (FunctionResultContent)chatItem;
+                    AssertExtensions.EqualFunctionCallResults(expectedFunctionResult.Result, chatFunctionResult.Result);
+                }
+            }
+        }
+    }
+
     /// <summary>
     /// Asserts that the two function call parameters are equal, up to JSON equivalence.
     /// </summary>
diff --git a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/FunctionApprovalRequestContentTests.cs b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/FunctionApprovalRequestContentTests.cs
new file mode 100644
index 00000000000..35f3836b65e
--- /dev/null
+++ b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/FunctionApprovalRequestContentTests.cs
@@ -0,0 +1,54 @@
+// 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 Xunit;
+
+namespace Microsoft.Extensions.AI.Contents;
+
+public class FunctionApprovalRequestContentTests
+{
+    [Fact]
+    public void Constructor_InvalidArguments_Throws()
+    {
+        FunctionCallContent functionCall = new("FCC1", "TestFunction");
+
+        Assert.Throws<ArgumentNullException>("id", () => new FunctionApprovalRequestContent(null!, functionCall));
+        Assert.Throws<ArgumentException>("id", () => new FunctionApprovalRequestContent("", functionCall));
+        Assert.Throws<ArgumentException>("id", () => new FunctionApprovalRequestContent("\r\t\n ", functionCall));
+
+        Assert.Throws<ArgumentNullException>("functionCall", () => new FunctionApprovalRequestContent("id", null!));
+    }
+
+    [Theory]
+    [InlineData("abc")]
+    [InlineData("123")]
+    [InlineData("!@#")]
+    public void Constructor_Roundtrips(string id)
+    {
+        FunctionCallContent functionCall = new("FCC1", "TestFunction");
+
+        FunctionApprovalRequestContent content = new(id, functionCall);
+
+        Assert.Same(id, content.Id);
+        Assert.Same(functionCall, content.FunctionCall);
+    }
+
+    [Theory]
+    [InlineData(true)]
+    [InlineData(false)]
+    public void CreateResponse_ReturnsExpectedResponse(bool approved)
+    {
+        string id = "req-1";
+        FunctionCallContent functionCall = new("FCC1", "TestFunction");
+
+        FunctionApprovalRequestContent content = new(id, functionCall);
+
+        var response = content.CreateResponse(approved);
+
+        Assert.NotNull(response);
+        Assert.Same(id, response.Id);
+        Assert.Equal(approved, response.Approved);
+        Assert.Same(functionCall, response.FunctionCall);
+    }
+}
diff --git a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/FunctionApprovalResponseContentTests.cs b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/FunctionApprovalResponseContentTests.cs
new file mode 100644
index 00000000000..9ae17faa192
--- /dev/null
+++ b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/FunctionApprovalResponseContentTests.cs
@@ -0,0 +1,36 @@
+// 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 Xunit;
+
+namespace Microsoft.Extensions.AI.Contents;
+
+public class FunctionApprovalResponseContentTests
+{
+    [Fact]
+    public void Constructor_InvalidArguments_Throws()
+    {
+        FunctionCallContent functionCall = new("FCC1", "TestFunction");
+
+        Assert.Throws<ArgumentNullException>("id", () => new FunctionApprovalResponseContent(null!, true, functionCall));
+        Assert.Throws<ArgumentException>("id", () => new FunctionApprovalResponseContent("", true, functionCall));
+        Assert.Throws<ArgumentException>("id", () => new FunctionApprovalResponseContent("\r\t\n ", true, functionCall));
+
+        Assert.Throws<ArgumentNullException>("functionCall", () => new FunctionApprovalResponseContent("id", true, null!));
+    }
+
+    [Theory]
+    [InlineData("abc", true)]
+    [InlineData("123", false)]
+    [InlineData("!@#", true)]
+    public void Constructor_Roundtrips(string id, bool approved)
+    {
+        FunctionCallContent functionCall = new("FCC1", "TestFunction");
+        FunctionApprovalResponseContent content = new(id, approved, functionCall);
+
+        Assert.Same(id, content.Id);
+        Assert.Equal(approved, content.Approved);
+        Assert.Same(functionCall, content.FunctionCall);
+    }
+}
diff --git a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/UserInputRequestContentTests.cs b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/UserInputRequestContentTests.cs
new file mode 100644
index 00000000000..e5ac4bb3a76
--- /dev/null
+++ b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/UserInputRequestContentTests.cs
@@ -0,0 +1,37 @@
+// 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 Xunit;
+
+namespace Microsoft.Extensions.AI.Contents;
+
+public class UserInputRequestContentTests
+{
+    [Fact]
+    public void Constructor_InvalidArguments_Throws()
+    {
+        Assert.Throws<ArgumentNullException>("id", () => new TestUserInputRequestContent(null!));
+        Assert.Throws<ArgumentException>("id", () => new TestUserInputRequestContent(""));
+        Assert.Throws<ArgumentException>("id", () => new TestUserInputRequestContent("\r\t\n "));
+    }
+
+    [Theory]
+    [InlineData("abc")]
+    [InlineData("123")]
+    [InlineData("!@#")]
+    public void Constructor_Roundtrips(string id)
+    {
+        TestUserInputRequestContent content = new(id);
+
+        Assert.Equal(id, content.Id);
+    }
+
+    private sealed class TestUserInputRequestContent : UserInputRequestContent
+    {
+        public TestUserInputRequestContent(string id)
+            : base(id)
+        {
+        }
+    }
+}
diff --git a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/UserInputResponseContentTests.cs b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/UserInputResponseContentTests.cs
new file mode 100644
index 00000000000..7c39c52acc9
--- /dev/null
+++ b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/UserInputResponseContentTests.cs
@@ -0,0 +1,37 @@
+// 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 Xunit;
+
+namespace Microsoft.Extensions.AI.Contents;
+
+public class UserInputResponseContentTests
+{
+    [Fact]
+    public void Constructor_InvalidArguments_Throws()
+    {
+        Assert.Throws<ArgumentNullException>("id", () => new TestUserInputResponseContent(null!));
+        Assert.Throws<ArgumentException>("id", () => new TestUserInputResponseContent(""));
+        Assert.Throws<ArgumentException>("id", () => new TestUserInputResponseContent("\r\t\n "));
+    }
+
+    [Theory]
+    [InlineData("abc")]
+    [InlineData("123")]
+    [InlineData("!@#")]
+    public void Constructor_Roundtrips(string id)
+    {
+        TestUserInputResponseContent content = new(id);
+
+        Assert.Equal(id, content.Id);
+    }
+
+    private class TestUserInputResponseContent : UserInputResponseContent
+    {
+        public TestUserInputResponseContent(string id)
+            : base(id)
+        {
+        }
+    }
+}
diff --git a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Functions/ApprovalRequiredAIFunctionTests.cs b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Functions/ApprovalRequiredAIFunctionTests.cs
new file mode 100644
index 00000000000..b8d0173d33e
--- /dev/null
+++ b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Functions/ApprovalRequiredAIFunctionTests.cs
@@ -0,0 +1,44 @@
+// 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.Threading.Tasks;
+using Xunit;
+
+namespace Microsoft.Extensions.AI.Functions;
+
+public class ApprovalRequiredAIFunctionTests
+{
+    [Fact]
+    public void Constructor_NullFunction_ThrowsArgumentNullException()
+    {
+        Assert.Throws<ArgumentNullException>("innerFunction", () => new ApprovalRequiredAIFunction(null!));
+    }
+
+    [Fact]
+    public void DelegatesToInnerFunction_Properties()
+    {
+        var inner = AIFunctionFactory.Create(() => 42);
+        var func = new ApprovalRequiredAIFunction(inner);
+
+        Assert.Equal(inner.Name, func.Name);
+        Assert.Equal(inner.Description, func.Description);
+        Assert.Equal(inner.JsonSchema, func.JsonSchema);
+        Assert.Equal(inner.ReturnJsonSchema, func.ReturnJsonSchema);
+        Assert.Same(inner.JsonSerializerOptions, func.JsonSerializerOptions);
+        Assert.Same(inner.UnderlyingMethod, func.UnderlyingMethod);
+        Assert.Same(inner.AdditionalProperties, func.AdditionalProperties);
+        Assert.Equal(inner.ToString(), func.ToString());
+    }
+
+    [Fact]
+    public async Task InvokeAsync_DelegatesToInnerFunction()
+    {
+        var inner = AIFunctionFactory.Create(() => "result");
+        var func = new ApprovalRequiredAIFunction(inner);
+
+        var result = await func.InvokeAsync();
+
+        Assert.Equal("result", result?.ToString());
+    }
+}
diff --git a/test/Libraries/Microsoft.Extensions.AI.Tests/ChatCompletion/FunctionInvokingChatClientApprovalsTests.cs b/test/Libraries/Microsoft.Extensions.AI.Tests/ChatCompletion/FunctionInvokingChatClientApprovalsTests.cs
new file mode 100644
index 00000000000..a0836a864c4
--- /dev/null
+++ b/test/Libraries/Microsoft.Extensions.AI.Tests/ChatCompletion/FunctionInvokingChatClientApprovalsTests.cs
@@ -0,0 +1,905 @@
+// 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 System.Linq;
+using System.Runtime.CompilerServices;
+using System.Threading;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace Microsoft.Extensions.AI.ChatCompletion;
+
+public class FunctionInvokingChatClientApprovalsTests
+{
+    [Theory]
+    [InlineData(false)]
+    [InlineData(true)]
+    public async Task AllFunctionCallsReplacedWithApprovalsWhenAllRequireApprovalAsync(bool useAdditionalTools)
+    {
+        AITool[] tools =
+        [
+            new ApprovalRequiredAIFunction(
+                AIFunctionFactory.Create(() => "Result 1", "Func1")),
+            new ApprovalRequiredAIFunction(
+                AIFunctionFactory.Create((int i) => $"Result 2: {i}", "Func2")),
+        ];
+
+        var options = new ChatOptions
+        {
+            Tools = useAdditionalTools ? null : tools
+        };
+
+        List<ChatMessage> input =
+        [
+            new ChatMessage(ChatRole.User, "hello"),
+        ];
+
+        List<ChatMessage> downstreamClientOutput =
+        [
+            new ChatMessage(ChatRole.Assistant, [new FunctionCallContent("callId1", "Func1"), new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } })]),
+        ];
+
+        List<ChatMessage> expectedOutput =
+        [
+            new ChatMessage(ChatRole.Assistant,
+            [
+                new FunctionApprovalRequestContent("callId1", new FunctionCallContent("callId1", "Func1")),
+                new FunctionApprovalRequestContent("callId2", new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } }))
+            ])
+        ];
+
+        await InvokeAndAssertAsync(options, input, downstreamClientOutput, expectedOutput, additionalTools: useAdditionalTools ? tools : null);
+
+        await InvokeAndAssertStreamingAsync(options, input, downstreamClientOutput, expectedOutput, additionalTools: useAdditionalTools ? tools : null);
+    }
+
+    [Fact]
+    public async Task AllFunctionCallsReplacedWithApprovalsWhenAnyRequireApprovalAsync()
+    {
+        var options = new ChatOptions
+        {
+            Tools =
+            [
+                new ApprovalRequiredAIFunction(AIFunctionFactory.Create(() => "Result 1", "Func1")),
+                AIFunctionFactory.Create((int i) => $"Result 2: {i}", "Func2"),
+            ]
+        };
+
+        List<ChatMessage> input =
+        [
+            new ChatMessage(ChatRole.User, "hello"),
+        ];
+
+        List<ChatMessage> downstreamClientOutput =
+        [
+            new ChatMessage(ChatRole.Assistant, [new FunctionCallContent("callId1", "Func1"), new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } })]),
+        ];
+
+        List<ChatMessage> expectedOutput =
+        [
+            new ChatMessage(ChatRole.Assistant,
+            [
+                new FunctionApprovalRequestContent("callId1", new FunctionCallContent("callId1", "Func1")),
+                new FunctionApprovalRequestContent("callId2", new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } }))
+            ])
+        ];
+
+        await InvokeAndAssertAsync(options, input, downstreamClientOutput, expectedOutput);
+
+        await InvokeAndAssertStreamingAsync(options, input, downstreamClientOutput, expectedOutput);
+    }
+
+    [Theory]
+    [InlineData(false)]
+    [InlineData(true)]
+    public async Task AllFunctionCallsReplacedWithApprovalsWhenAnyRequestOrAdditionalRequireApprovalAsync(bool additionalToolsRequireApproval)
+    {
+        AIFunction func1 = AIFunctionFactory.Create(() => "Result 1", "Func1");
+        AIFunction func2 = AIFunctionFactory.Create((int i) => $"Result 2: {i}", "Func2");
+        AITool[] additionalTools =
+        [
+            additionalToolsRequireApproval ? new ApprovalRequiredAIFunction(func1) : func1,
+        ];
+
+        var options = new ChatOptions
+        {
+            Tools =
+            [
+                additionalToolsRequireApproval ? func2 : new ApprovalRequiredAIFunction(func2),
+            ]
+        };
+
+        List<ChatMessage> input =
+        [
+            new ChatMessage(ChatRole.User, "hello"),
+        ];
+
+        List<ChatMessage> downstreamClientOutput =
+        [
+            new ChatMessage(ChatRole.Assistant, [new FunctionCallContent("callId1", "Func1"), new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } })]),
+        ];
+
+        List<ChatMessage> expectedOutput =
+        [
+            new ChatMessage(ChatRole.Assistant,
+            [
+                new FunctionApprovalRequestContent("callId1", new FunctionCallContent("callId1", "Func1")),
+                new FunctionApprovalRequestContent("callId2", new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } }))
+            ])
+        ];
+
+        await InvokeAndAssertAsync(options, input, downstreamClientOutput, expectedOutput, additionalTools: additionalTools);
+
+        await InvokeAndAssertStreamingAsync(options, input, downstreamClientOutput, expectedOutput, additionalTools: additionalTools);
+    }
+
+    [Fact]
+    public async Task ApprovedApprovalResponsesAreExecutedAsync()
+    {
+        var options = new ChatOptions
+        {
+            Tools =
+            [
+                new ApprovalRequiredAIFunction(AIFunctionFactory.Create(() => "Result 1", "Func1")),
+                AIFunctionFactory.Create((int i) => $"Result 2: {i}", "Func2"),
+            ]
+        };
+
+        List<ChatMessage> input =
+        [
+            new ChatMessage(ChatRole.User, "hello"),
+            new ChatMessage(ChatRole.Assistant,
+            [
+                new FunctionApprovalRequestContent("callId1", new FunctionCallContent("callId1", "Func1")),
+                new FunctionApprovalRequestContent("callId2", new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } }))
+            ]) { MessageId = "resp1" },
+            new ChatMessage(ChatRole.User,
+            [
+                new FunctionApprovalResponseContent("callId1", true, new FunctionCallContent("callId1", "Func1")),
+                new FunctionApprovalResponseContent("callId2", true, new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } }))
+            ]),
+        ];
+
+        List<ChatMessage> expectedDownstreamClientInput =
+        [
+            new ChatMessage(ChatRole.User, "hello"),
+            new ChatMessage(ChatRole.Assistant, [new FunctionCallContent("callId1", "Func1"), new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } })]),
+            new ChatMessage(ChatRole.Tool, [new FunctionResultContent("callId1", result: "Result 1"), new FunctionResultContent("callId2", result: "Result 2: 42")]),
+        ];
+
+        List<ChatMessage> downstreamClientOutput =
+        [
+            new ChatMessage(ChatRole.Assistant, "world"),
+        ];
+
+        List<ChatMessage> output =
+        [
+            new ChatMessage(ChatRole.Assistant, [new FunctionCallContent("callId1", "Func1"), new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } })]),
+            new ChatMessage(ChatRole.Tool, [new FunctionResultContent("callId1", result: "Result 1"), new FunctionResultContent("callId2", result: "Result 2: 42")]),
+            new ChatMessage(ChatRole.Assistant, "world"),
+        ];
+
+        await InvokeAndAssertAsync(options, input, downstreamClientOutput, output, expectedDownstreamClientInput);
+
+        await InvokeAndAssertStreamingAsync(options, input, downstreamClientOutput, output, expectedDownstreamClientInput);
+    }
+
+    [Fact]
+    public async Task ApprovedApprovalResponsesFromSeparateFCCMessagesAreExecutedAsync()
+    {
+        var options = new ChatOptions
+        {
+            Tools =
+            [
+                new ApprovalRequiredAIFunction(AIFunctionFactory.Create(() => "Result 1", "Func1")),
+                AIFunctionFactory.Create((int i) => $"Result 2: {i}", "Func2"),
+            ]
+        };
+
+        List<ChatMessage> input =
+        [
+            new ChatMessage(ChatRole.User, "hello"),
+            new ChatMessage(ChatRole.Assistant,
+            [
+                new FunctionApprovalRequestContent("callId1", new FunctionCallContent("callId1", "Func1")),
+            ]) { MessageId = "resp1" },
+            new ChatMessage(ChatRole.Assistant,
+            [
+                new FunctionApprovalRequestContent("callId2", new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } }))
+            ]) { MessageId = "resp2" },
+            new ChatMessage(ChatRole.User,
+            [
+                new FunctionApprovalResponseContent("callId1", true, new FunctionCallContent("callId1", "Func1")),
+            ]),
+            new ChatMessage(ChatRole.User,
+            [
+                new FunctionApprovalResponseContent("callId2", true, new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } }))
+            ]),
+        ];
+
+        List<ChatMessage> expectedDownstreamClientInput =
+        [
+            new ChatMessage(ChatRole.User, "hello"),
+            new ChatMessage(ChatRole.Assistant, [new FunctionCallContent("callId1", "Func1")]) { MessageId = "resp1" },
+            new ChatMessage(ChatRole.Assistant, [new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } })]) { MessageId = "resp2" },
+            new ChatMessage(ChatRole.Tool, [new FunctionResultContent("callId1", result: "Result 1"), new FunctionResultContent("callId2", result: "Result 2: 42")]),
+        ];
+
+        List<ChatMessage> downstreamClientOutput =
+        [
+            new ChatMessage(ChatRole.Assistant, "world"),
+        ];
+
+        List<ChatMessage> output =
+        [
+            new ChatMessage(ChatRole.Assistant, [new FunctionCallContent("callId1", "Func1")]) { MessageId = "resp1" },
+            new ChatMessage(ChatRole.Assistant, [new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } })]) { MessageId = "resp2" },
+            new ChatMessage(ChatRole.Tool, [new FunctionResultContent("callId1", result: "Result 1"), new FunctionResultContent("callId2", result: "Result 2: 42")]),
+            new ChatMessage(ChatRole.Assistant, "world"),
+        ];
+
+        await InvokeAndAssertAsync(options, input, downstreamClientOutput, output, expectedDownstreamClientInput);
+
+        await InvokeAndAssertStreamingAsync(options, input, downstreamClientOutput, output, expectedDownstreamClientInput);
+    }
+
+    [Fact]
+    public async Task RejectedApprovalResponsesAreFailedAsync()
+    {
+        var options = new ChatOptions
+        {
+            Tools =
+            [
+                new ApprovalRequiredAIFunction(AIFunctionFactory.Create(() => "Result 1", "Func1")),
+                AIFunctionFactory.Create((int i) => $"Result 2: {i}", "Func2"),
+            ]
+        };
+
+        List<ChatMessage> input =
+        [
+            new ChatMessage(ChatRole.User, "hello"),
+            new ChatMessage(ChatRole.Assistant,
+            [
+                new FunctionApprovalRequestContent("callId1", new FunctionCallContent("callId1", "Func1")),
+                new FunctionApprovalRequestContent("callId2", new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } }))
+            ]) { MessageId = "resp1" },
+            new ChatMessage(ChatRole.User,
+            [
+                new FunctionApprovalResponseContent("callId1", false, new FunctionCallContent("callId1", "Func1")),
+                new FunctionApprovalResponseContent("callId2", false, new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } }))
+            ]),
+        ];
+
+        List<ChatMessage> expectedDownstreamClientInput =
+        [
+            new ChatMessage(ChatRole.User, "hello"),
+            new ChatMessage(ChatRole.Assistant, [new FunctionCallContent("callId1", "Func1"), new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } })]),
+            new ChatMessage(ChatRole.Tool,
+            [
+                new FunctionResultContent("callId1", result: "Error: Tool call invocation was rejected by user."),
+                new FunctionResultContent("callId2", result: "Error: Tool call invocation was rejected by user.")
+            ]),
+        ];
+
+        List<ChatMessage> downstreamClientOutput =
+        [
+            new ChatMessage(ChatRole.Assistant, "world"),
+        ];
+
+        List<ChatMessage> output =
+        [
+            new ChatMessage(ChatRole.Assistant, [new FunctionCallContent("callId1", "Func1"), new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } })]),
+            new ChatMessage(ChatRole.Tool,
+            [
+                new FunctionResultContent("callId1", result: "Error: Tool call invocation was rejected by user."),
+                new FunctionResultContent("callId2", result: "Error: Tool call invocation was rejected by user.")
+            ]),
+            new ChatMessage(ChatRole.Assistant, "world"),
+        ];
+
+        await InvokeAndAssertAsync(options, input, downstreamClientOutput, output, expectedDownstreamClientInput);
+
+        await InvokeAndAssertStreamingAsync(options, input, downstreamClientOutput, output, expectedDownstreamClientInput);
+    }
+
+    [Fact]
+    public async Task MixedApprovedAndRejectedApprovalResponsesAreExecutedAndFailedAsync()
+    {
+        var options = new ChatOptions
+        {
+            Tools =
+            [
+                new ApprovalRequiredAIFunction(AIFunctionFactory.Create(() => "Result 1", "Func1")),
+                AIFunctionFactory.Create((int i) => $"Result 2: {i}", "Func2"),
+            ]
+        };
+
+        List<ChatMessage> input =
+        [
+            new ChatMessage(ChatRole.User, "hello"),
+            new ChatMessage(ChatRole.Assistant,
+            [
+                new FunctionApprovalRequestContent("callId1", new FunctionCallContent("callId1", "Func1")),
+                new FunctionApprovalRequestContent("callId2", new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } }))
+            ]) { MessageId = "resp1" },
+            new ChatMessage(ChatRole.User,
+            [
+                new FunctionApprovalResponseContent("callId1", false, new FunctionCallContent("callId1", "Func1")),
+                new FunctionApprovalResponseContent("callId2", true, new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } }))
+            ]),
+        ];
+
+        List<ChatMessage> expectedDownstreamClientInput =
+        [
+            new ChatMessage(ChatRole.User, "hello"),
+            new ChatMessage(ChatRole.Assistant, [new FunctionCallContent("callId1", "Func1"), new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } })]),
+            new ChatMessage(ChatRole.Tool, [new FunctionResultContent("callId1", result: "Error: Tool call invocation was rejected by user.")]),
+            new ChatMessage(ChatRole.Tool, [new FunctionResultContent("callId2", result: "Result 2: 42")]),
+        ];
+
+        List<ChatMessage> downstreamClientOutput =
+        [
+            new ChatMessage(ChatRole.Assistant, "world"),
+        ];
+
+        List<ChatMessage> nonStreamingOutput =
+        [
+            new ChatMessage(ChatRole.Assistant, [new FunctionCallContent("callId1", "Func1"), new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } })]),
+            new ChatMessage(ChatRole.Tool, [new FunctionResultContent("callId1", result: "Error: Tool call invocation was rejected by user.")]),
+            new ChatMessage(ChatRole.Tool, [new FunctionResultContent("callId2", result: "Result 2: 42")]),
+            new ChatMessage(ChatRole.Assistant, "world"),
+        ];
+
+        List<ChatMessage> streamingOutput =
+        [
+            new ChatMessage(ChatRole.Assistant, [new FunctionCallContent("callId1", "Func1"), new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } })]),
+            new ChatMessage(ChatRole.Tool,
+            [
+                new FunctionResultContent("callId1", result: "Error: Tool call invocation was rejected by user."),
+                new FunctionResultContent("callId2", result: "Result 2: 42")
+            ]),
+            new ChatMessage(ChatRole.Assistant, "world"),
+        ];
+
+        await InvokeAndAssertAsync(options, input, downstreamClientOutput, nonStreamingOutput, expectedDownstreamClientInput);
+
+        await InvokeAndAssertStreamingAsync(options, input, downstreamClientOutput, streamingOutput, expectedDownstreamClientInput);
+    }
+
+    [Fact]
+    public async Task ApprovedInputsAreExecutedAndFunctionResultsAreConvertedAsync()
+    {
+        var options = new ChatOptions
+        {
+            Tools =
+            [
+                AIFunctionFactory.Create(() => "Result 1", "Func1"),
+                new ApprovalRequiredAIFunction(AIFunctionFactory.Create((int i) => $"Result 2: {i}", "Func2")),
+            ]
+        };
+
+        List<ChatMessage> input =
+        [
+            new ChatMessage(ChatRole.User, "hello"),
+            new ChatMessage(ChatRole.Assistant,
+            [
+                new FunctionApprovalRequestContent("callId1", new FunctionCallContent("callId1", "Func1")),
+                new FunctionApprovalRequestContent("callId2", new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } }))
+            ]) { MessageId = "resp1" },
+            new ChatMessage(ChatRole.User,
+            [
+                new FunctionApprovalResponseContent("callId1", true, new FunctionCallContent("callId1", "Func1")),
+                new FunctionApprovalResponseContent("callId2", true, new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } }))
+            ]),
+        ];
+
+        List<ChatMessage> expectedDownstreamClientInput =
+        [
+            new ChatMessage(ChatRole.User, "hello"),
+            new ChatMessage(ChatRole.Assistant, [new FunctionCallContent("callId1", "Func1"), new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } })]),
+            new ChatMessage(ChatRole.Tool, [new FunctionResultContent("callId1", result: "Result 1"), new FunctionResultContent("callId2", result: "Result 2: 42")]),
+        ];
+
+        List<ChatMessage> downstreamClientOutput =
+        [
+            new ChatMessage(ChatRole.Assistant, [new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 3 } })]),
+        ];
+
+        List<ChatMessage> output =
+        [
+            new ChatMessage(ChatRole.Assistant, [new FunctionCallContent("callId1", "Func1"), new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } })]),
+            new ChatMessage(ChatRole.Tool, [new FunctionResultContent("callId1", result: "Result 1"), new FunctionResultContent("callId2", result: "Result 2: 42")]),
+            new ChatMessage(ChatRole.Assistant,
+            [
+                new FunctionApprovalRequestContent("callId2", new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 3 } }))
+            ]),
+        ];
+
+        await InvokeAndAssertAsync(options, input, downstreamClientOutput, output, expectedDownstreamClientInput);
+
+        await InvokeAndAssertStreamingAsync(options, input, downstreamClientOutput, output, expectedDownstreamClientInput);
+    }
+
+    [Fact]
+    public async Task AlreadyExecutedApprovalsAreIgnoredAsync()
+    {
+        var options = new ChatOptions
+        {
+            Tools =
+            [
+                AIFunctionFactory.Create(() => "Result 1", "Func1"),
+                new ApprovalRequiredAIFunction(AIFunctionFactory.Create((int i) => $"Result 2: {i}", "Func2")),
+            ]
+        };
+
+        List<ChatMessage> input =
+        [
+            new ChatMessage(ChatRole.User, "hello"),
+            new ChatMessage(ChatRole.Assistant,
+            [
+                new FunctionApprovalRequestContent("callId1", new FunctionCallContent("callId1", "Func1")),
+                new FunctionApprovalRequestContent("callId2", new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } }))
+            ]) { MessageId = "resp1" },
+            new ChatMessage(ChatRole.User,
+            [
+                new FunctionApprovalResponseContent("callId1", true, new FunctionCallContent("callId1", "Func1")),
+                new FunctionApprovalResponseContent("callId2", true, new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } }))
+            ]),
+            new ChatMessage(ChatRole.Assistant, [new FunctionCallContent("callId1", "Func1"), new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } })]),
+            new ChatMessage(ChatRole.Tool, [new FunctionResultContent("callId1", result: "Result 1"), new FunctionResultContent("callId2", result: "Result 2: 42")]),
+            new ChatMessage(ChatRole.Assistant,
+            [
+                new FunctionApprovalRequestContent("callId3", new FunctionCallContent("callId3", "Func1")),
+            ]) { MessageId = "resp2" },
+            new ChatMessage(ChatRole.User,
+            [
+                new FunctionApprovalResponseContent("callId3", true, new FunctionCallContent("callId3", "Func1")),
+            ]),
+        ];
+
+        List<ChatMessage> expectedDownstreamClientInput =
+        [
+            new ChatMessage(ChatRole.User, "hello"),
+            new ChatMessage(ChatRole.Assistant, [new FunctionCallContent("callId1", "Func1"), new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } })]),
+            new ChatMessage(ChatRole.Tool, [new FunctionResultContent("callId1", result: "Result 1"), new FunctionResultContent("callId2", result: "Result 2: 42")]),
+            new ChatMessage(ChatRole.Assistant, [new FunctionCallContent("callId3", "Func1")]),
+            new ChatMessage(ChatRole.Tool, [new FunctionResultContent("callId3", result: "Result 1")]),
+        ];
+
+        List<ChatMessage> downstreamClientOutput =
+        [
+            new ChatMessage(ChatRole.Assistant, "World"),
+        ];
+
+        List<ChatMessage> output =
+        [
+            new ChatMessage(ChatRole.Assistant, [new FunctionCallContent("callId3", "Func1")]),
+            new ChatMessage(ChatRole.Tool, [new FunctionResultContent("callId3", result: "Result 1")]),
+            new ChatMessage(ChatRole.Assistant, "World"),
+        ];
+
+        await InvokeAndAssertAsync(options, input, downstreamClientOutput, output, expectedDownstreamClientInput);
+
+        await InvokeAndAssertStreamingAsync(options, input, downstreamClientOutput, output, expectedDownstreamClientInput);
+    }
+
+    [Fact]
+    public async Task ApprovalRequestWithoutApprovalResponseThrowsAsync()
+    {
+        var options = new ChatOptions
+        {
+            Tools =
+            [
+                new ApprovalRequiredAIFunction(AIFunctionFactory.Create(() => "Result 1", "Func1")),
+                AIFunctionFactory.Create((int i) => $"Result 2: {i}", "Func2"),
+            ]
+        };
+
+        List<ChatMessage> input =
+        [
+            new ChatMessage(ChatRole.User, "hello"),
+            new ChatMessage(ChatRole.Assistant,
+            [
+                new FunctionApprovalRequestContent("callId1", new FunctionCallContent("callId1", "Func1")),
+            ]) { MessageId = "resp1" },
+        ];
+
+        var invokeException = await Assert.ThrowsAsync<InvalidOperationException>(
+            async () => await InvokeAndAssertAsync(options, input, [], [], []));
+        Assert.Equal("FunctionApprovalRequestContent found with FunctionCall.CallId(s) 'callId1' that have no matching FunctionApprovalResponseContent.", invokeException.Message);
+
+        var invokeStreamingException = await Assert.ThrowsAsync<InvalidOperationException>(
+            async () => await InvokeAndAssertStreamingAsync(options, input, [], [], []));
+        Assert.Equal("FunctionApprovalRequestContent found with FunctionCall.CallId(s) 'callId1' that have no matching FunctionApprovalResponseContent.", invokeStreamingException.Message);
+    }
+
+    [Fact]
+    public async Task ApprovedApprovalResponsesWithoutApprovalRequestAreExecutedAsync()
+    {
+        var options = new ChatOptions
+        {
+            Tools =
+            [
+                new ApprovalRequiredAIFunction(AIFunctionFactory.Create(() => "Result 1", "Func1")),
+                AIFunctionFactory.Create((int i) => $"Result 2: {i}", "Func2"),
+            ]
+        };
+
+        List<ChatMessage> input =
+        [
+            new ChatMessage(ChatRole.User, "hello"),
+            new ChatMessage(ChatRole.User,
+            [
+                new FunctionApprovalResponseContent("callId1", true, new FunctionCallContent("callId1", "Func1")),
+                new FunctionApprovalResponseContent("callId2", true, new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } }))
+            ]),
+        ];
+
+        List<ChatMessage> expectedDownstreamClientInput =
+        [
+            new ChatMessage(ChatRole.User, "hello"),
+            new ChatMessage(ChatRole.Assistant, [new FunctionCallContent("callId1", "Func1"), new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } })]),
+            new ChatMessage(ChatRole.Tool, [new FunctionResultContent("callId1", result: "Result 1"), new FunctionResultContent("callId2", result: "Result 2: 42")]),
+        ];
+
+        List<ChatMessage> downstreamClientOutput =
+        [
+            new ChatMessage(ChatRole.Assistant, "world"),
+        ];
+
+        List<ChatMessage> output =
+        [
+            new ChatMessage(ChatRole.Assistant, [new FunctionCallContent("callId1", "Func1"), new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } })]),
+            new ChatMessage(ChatRole.Tool, [new FunctionResultContent("callId1", result: "Result 1"), new FunctionResultContent("callId2", result: "Result 2: 42")]),
+            new ChatMessage(ChatRole.Assistant, "world"),
+        ];
+
+        await InvokeAndAssertAsync(options, input, downstreamClientOutput, output, expectedDownstreamClientInput);
+
+        await InvokeAndAssertStreamingAsync(options, input, downstreamClientOutput, output, expectedDownstreamClientInput);
+    }
+
+    [Fact]
+    public async Task FunctionCallContentIsNotPassedToDownstreamServiceWithServiceThreadsAsync()
+    {
+        var options = new ChatOptions
+        {
+            Tools =
+            [
+                new ApprovalRequiredAIFunction(AIFunctionFactory.Create(() => "Result 1", "Func1")),
+                AIFunctionFactory.Create((int i) => $"Result 2: {i}", "Func2"),
+            ],
+            ConversationId = "test-conversation",
+        };
+
+        List<ChatMessage> input =
+        [
+            new ChatMessage(ChatRole.User,
+            [
+                new FunctionApprovalResponseContent("callId1", true, new FunctionCallContent("callId1", "Func1")),
+                new FunctionApprovalResponseContent("callId2", true, new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } }))
+            ]),
+        ];
+
+        List<ChatMessage> expectedDownstreamClientInput =
+        [
+            new ChatMessage(ChatRole.Tool, [new FunctionResultContent("callId1", result: "Result 1"), new FunctionResultContent("callId2", result: "Result 2: 42")]),
+        ];
+
+        List<ChatMessage> downstreamClientOutput =
+        [
+            new ChatMessage(ChatRole.Assistant, "world"),
+        ];
+
+        List<ChatMessage> output =
+        [
+            new ChatMessage(ChatRole.Assistant, [new FunctionCallContent("callId1", "Func1"), new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } })]),
+            new ChatMessage(ChatRole.Tool, [new FunctionResultContent("callId1", result: "Result 1"), new FunctionResultContent("callId2", result: "Result 2: 42")]),
+            new ChatMessage(ChatRole.Assistant, "world"),
+        ];
+
+        await InvokeAndAssertAsync(options, input, downstreamClientOutput, output, expectedDownstreamClientInput);
+
+        await InvokeAndAssertStreamingAsync(options, input, downstreamClientOutput, output, expectedDownstreamClientInput);
+    }
+
+    /// <summary>
+    /// Since we do not have a way of supporting both functions that require approval and those that do not
+    /// in one invocation, we always require all function calls to be approved if any require approval.
+    /// If we are therefore unsure as to whether we will encounter a function call that requires approval,
+    /// we have to wait until we find one before yielding any function call content.
+    /// If we don't have any function calls that require approval at all though, we can just yield all content normally
+    /// since this issue won't apply.
+    /// </summary>
+    [Fact]
+    public async Task FunctionCallContentIsYieldedImmediatelyIfNoApprovalRequiredWhenStreamingAsync()
+    {
+        var options = new ChatOptions
+        {
+            Tools =
+            [
+                AIFunctionFactory.Create(() => "Result 1", "Func1"),
+                AIFunctionFactory.Create((int i) => $"Result 2: {i}", "Func2"),
+            ]
+        };
+
+        List<ChatMessage> input = [new ChatMessage(ChatRole.User, "hello")];
+
+        Func<ChatClientBuilder, ChatClientBuilder> configurePipeline = b => b.Use(s => new FunctionInvokingChatClient(s));
+        using CancellationTokenSource cts = new();
+
+        var updateYieldCount = 0;
+
+        async IAsyncEnumerable<ChatResponseUpdate> YieldInnerClientUpdates(
+            IEnumerable<ChatMessage> contents, ChatOptions? actualOptions, [EnumeratorCancellation] CancellationToken actualCancellationToken)
+        {
+            Assert.Equal(cts.Token, actualCancellationToken);
+            await Task.Yield();
+            var messageId = Guid.NewGuid().ToString("N");
+
+            updateYieldCount++;
+            yield return new ChatResponseUpdate(ChatRole.Assistant, [new FunctionCallContent("callId1", "Func1")]) { MessageId = messageId };
+            updateYieldCount++;
+            yield return
+                new ChatResponseUpdate(
+                    ChatRole.Assistant,
+                    [
+                        new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } })
+                    ])
+                { MessageId = messageId };
+        }
+
+        using var innerClient = new TestChatClient { GetStreamingResponseAsyncCallback = YieldInnerClientUpdates };
+        IChatClient service = configurePipeline(innerClient.AsBuilder()).Build();
+
+        var updates = service.GetStreamingResponseAsync(new EnumeratedOnceEnumerable<ChatMessage>(input), options, cts.Token);
+
+        var updateCount = 0;
+        await foreach (var update in updates)
+        {
+            if (updateCount < 2)
+            {
+                var functionCall = update.Contents.OfType<FunctionCallContent>().First();
+                if (functionCall.CallId == "callId1")
+                {
+                    Assert.Equal("Func1", functionCall.Name);
+                    Assert.Equal(1, updateYieldCount);
+                }
+                else if (functionCall.CallId == "callId2")
+                {
+                    Assert.Equal("Func2", functionCall.Name);
+                    Assert.Equal(2, updateYieldCount);
+                }
+            }
+
+            updateCount++;
+        }
+    }
+
+    /// <summary>
+    /// Since we do not have a way of supporting both functions that require approval and those that do not
+    /// in one invocation, we always require all function calls to be approved if any require approval.
+    /// If we are therefore unsure as to whether we will encounter a function call that requires approval,
+    /// we have to wait until we find one before yielding any function call content.
+    /// We can however, yield any other content until we encounter the first function call.
+    /// </summary>
+    [Fact]
+    public async Task FunctionCalsAreBufferedUntilApprovalRequirementEncounteredWhenStreamingAsync()
+    {
+        var options = new ChatOptions
+        {
+            Tools =
+            [
+                AIFunctionFactory.Create(() => "Result 1", "Func1"),
+                new ApprovalRequiredAIFunction(AIFunctionFactory.Create((int i) => $"Result 2: {i}", "Func2")),
+                AIFunctionFactory.Create(() => "Result 3", "Func3"),
+            ]
+        };
+
+        List<ChatMessage> input = [new ChatMessage(ChatRole.User, "hello")];
+
+        Func<ChatClientBuilder, ChatClientBuilder> configurePipeline = b => b.Use(s => new FunctionInvokingChatClient(s));
+        using CancellationTokenSource cts = new();
+
+        var updateYieldCount = 0;
+
+        async IAsyncEnumerable<ChatResponseUpdate> YieldInnerClientUpdates(
+            IEnumerable<ChatMessage> contents, ChatOptions? actualOptions, [EnumeratorCancellation] CancellationToken actualCancellationToken)
+        {
+            Assert.Equal(cts.Token, actualCancellationToken);
+            await Task.Yield();
+            var messageId = Guid.NewGuid().ToString("N");
+
+            updateYieldCount++;
+            yield return new ChatResponseUpdate(ChatRole.Assistant, [new TextContent("Text 1")]) { MessageId = messageId };
+            updateYieldCount++;
+            yield return new ChatResponseUpdate(ChatRole.Assistant, [new TextContent("Text 2")]) { MessageId = messageId };
+            updateYieldCount++;
+            yield return new ChatResponseUpdate(ChatRole.Assistant, [new FunctionCallContent("callId1", "Func1")]) { MessageId = messageId };
+            updateYieldCount++;
+            yield return new ChatResponseUpdate(
+                ChatRole.Assistant,
+                [
+                    new FunctionCallContent("callId2", "Func2", arguments: new Dictionary<string, object?> { { "i", 42 } })
+                ])
+            { MessageId = messageId };
+            updateYieldCount++;
+            yield return new ChatResponseUpdate(ChatRole.Assistant, [new FunctionCallContent("callId1", "Func3")]) { MessageId = messageId };
+        }
+
+        using var innerClient = new TestChatClient { GetStreamingResponseAsyncCallback = YieldInnerClientUpdates };
+        IChatClient service = configurePipeline(innerClient.AsBuilder()).Build();
+
+        var updates = service.GetStreamingResponseAsync(new EnumeratedOnceEnumerable<ChatMessage>(input), options, cts.Token);
+
+        var updateCount = 0;
+        await foreach (var update in updates)
+        {
+            switch (updateCount)
+            {
+                case 0:
+                    Assert.Equal("Text 1", update.Contents.OfType<TextContent>().First().Text);
+
+                    // First content should be yielded immedately, since we don't have any function calls yet.
+                    Assert.Equal(1, updateYieldCount);
+                    break;
+                case 1:
+                    Assert.Equal("Text 2", update.Contents.OfType<TextContent>().First().Text);
+
+                    // Second content should be yielded immedately, since we don't have any function calls yet.
+                    Assert.Equal(2, updateYieldCount);
+                    break;
+                case 2:
+                    var approvalRequest1 = update.Contents.OfType<FunctionApprovalRequestContent>().First();
+                    Assert.Equal("callId1", approvalRequest1.FunctionCall.CallId);
+                    Assert.Equal("Func1", approvalRequest1.FunctionCall.Name);
+
+                    // Third content should have been buffered, since we have not yet encountered a function call that requires approval.
+                    Assert.Equal(4, updateYieldCount);
+                    break;
+                case 3:
+                    var approvalRequest2 = update.Contents.OfType<FunctionApprovalRequestContent>().First();
+                    Assert.Equal("callId2", approvalRequest2.FunctionCall.CallId);
+                    Assert.Equal("Func2", approvalRequest2.FunctionCall.Name);
+
+                    // Fourth content can be yielded immediately, since it is the first function call that requires approval.
+                    Assert.Equal(4, updateYieldCount);
+                    break;
+                case 4:
+                    var approvalRequest3 = update.Contents.OfType<FunctionApprovalRequestContent>().First();
+                    Assert.Equal("callId1", approvalRequest3.FunctionCall.CallId);
+                    Assert.Equal("Func3", approvalRequest3.FunctionCall.Name);
+
+                    // Fifth content can be yielded immediately, since we previously encountered a function call that requires approval.
+                    Assert.Equal(5, updateYieldCount);
+                    break;
+            }
+
+            updateCount++;
+        }
+    }
+
+    private static async Task<List<ChatMessage>> InvokeAndAssertAsync(
+        ChatOptions? options,
+        List<ChatMessage> input,
+        List<ChatMessage> downstreamClientOutput,
+        List<ChatMessage> expectedOutput,
+        List<ChatMessage>? expectedDownstreamClientInput = null,
+        Func<ChatClientBuilder, ChatClientBuilder>? configurePipeline = null,
+        AITool[]? additionalTools = null)
+    {
+        Assert.NotEmpty(input);
+
+        configurePipeline ??= b => b.Use(s => new FunctionInvokingChatClient(s) { AdditionalTools = additionalTools });
+
+        using CancellationTokenSource cts = new();
+        long expectedTotalTokenCounts = 0;
+
+        using var innerClient = new TestChatClient
+        {
+            GetResponseAsyncCallback = async (contents, actualOptions, actualCancellationToken) =>
+            {
+                Assert.Equal(cts.Token, actualCancellationToken);
+                if (expectedDownstreamClientInput is not null)
+                {
+                    AssertExtensions.EqualMessageLists(expectedDownstreamClientInput, contents.ToList());
+                }
+
+                await Task.Yield();
+
+                var usage = CreateRandomUsage();
+                expectedTotalTokenCounts += usage.InputTokenCount!.Value;
+
+                downstreamClientOutput.ForEach(m => m.MessageId = Guid.NewGuid().ToString("N"));
+                return new ChatResponse(downstreamClientOutput) { Usage = usage };
+            }
+        };
+
+        IChatClient service = configurePipeline(innerClient.AsBuilder()).Build();
+
+        var result = await service.GetResponseAsync(new EnumeratedOnceEnumerable<ChatMessage>(input), options, cts.Token);
+        Assert.NotNull(result);
+
+        var actualOutput = result.Messages as List<ChatMessage> ?? result.Messages.ToList();
+        AssertExtensions.EqualMessageLists(expectedOutput, actualOutput);
+
+        // Usage should be aggregated over all responses, including AdditionalUsage
+        var actualUsage = result.Usage!;
+        Assert.Equal(expectedTotalTokenCounts, actualUsage.InputTokenCount);
+        Assert.Equal(expectedTotalTokenCounts, actualUsage.OutputTokenCount);
+        Assert.Equal(expectedTotalTokenCounts, actualUsage.TotalTokenCount);
+        Assert.Equal(2, actualUsage.AdditionalCounts!.Count);
+        Assert.Equal(expectedTotalTokenCounts, actualUsage.AdditionalCounts["firstValue"]);
+        Assert.Equal(expectedTotalTokenCounts, actualUsage.AdditionalCounts["secondValue"]);
+
+        return actualOutput;
+    }
+
+    private static UsageDetails CreateRandomUsage()
+    {
+        // We'll set the same random number on all the properties so that, when determining the
+        // correct sum in tests, we only have to total the values once
+        var value = new Random().Next(100);
+        return new UsageDetails
+        {
+            InputTokenCount = value,
+            OutputTokenCount = value,
+            TotalTokenCount = value,
+            AdditionalCounts = new() { ["firstValue"] = value, ["secondValue"] = value },
+        };
+    }
+
+    private static async Task<List<ChatMessage>> InvokeAndAssertStreamingAsync(
+        ChatOptions? options,
+        List<ChatMessage> input,
+        List<ChatMessage> downstreamClientOutput,
+        List<ChatMessage> expectedOutput,
+        List<ChatMessage>? expectedDownstreamClientInput = null,
+        Func<ChatClientBuilder, ChatClientBuilder>? configurePipeline = null,
+        AITool[]? additionalTools = null)
+    {
+        Assert.NotEmpty(input);
+
+        configurePipeline ??= b => b.Use(s => new FunctionInvokingChatClient(s) { AdditionalTools = additionalTools });
+
+        using CancellationTokenSource cts = new();
+
+        using var innerClient = new TestChatClient
+        {
+            GetStreamingResponseAsyncCallback = (contents, actualOptions, actualCancellationToken) =>
+            {
+                Assert.Equal(cts.Token, actualCancellationToken);
+                if (expectedDownstreamClientInput is not null)
+                {
+                    AssertExtensions.EqualMessageLists(expectedDownstreamClientInput, contents.ToList());
+                }
+
+                downstreamClientOutput.ForEach(m => m.MessageId = Guid.NewGuid().ToString("N"));
+                return YieldAsync(new ChatResponse(downstreamClientOutput).ToChatResponseUpdates());
+            }
+        };
+
+        IChatClient service = configurePipeline(innerClient.AsBuilder()).Build();
+
+        var result = await service.GetStreamingResponseAsync(new EnumeratedOnceEnumerable<ChatMessage>(input), options, cts.Token).ToChatResponseAsync();
+        Assert.NotNull(result);
+
+        var actualOutput = result.Messages as List<ChatMessage> ?? result.Messages.ToList();
+
+        expectedOutput ??= input;
+        AssertExtensions.EqualMessageLists(expectedOutput, actualOutput);
+
+        return actualOutput;
+    }
+
+    private static async IAsyncEnumerable<T> YieldAsync<T>(params T[] items)
+    {
+        await Task.Yield();
+        foreach (var item in items)
+        {
+            yield return item;
+        }
+    }
+}
diff --git a/test/Libraries/Microsoft.Extensions.AI.Tests/ChatCompletion/FunctionInvokingChatClientTests.cs b/test/Libraries/Microsoft.Extensions.AI.Tests/ChatCompletion/FunctionInvokingChatClientTests.cs
index b9a71849034..0657cb7edfa 100644
--- a/test/Libraries/Microsoft.Extensions.AI.Tests/ChatCompletion/FunctionInvokingChatClientTests.cs
+++ b/test/Libraries/Microsoft.Extensions.AI.Tests/ChatCompletion/FunctionInvokingChatClientTests.cs
@@ -2,7 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
-using System.Collections;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
@@ -1231,37 +1230,7 @@ private static async Task<List<ChatMessage>> InvokeAndAssertAsync(
         chat.AddRange(result.Messages);
 
         expected ??= plan;
-        Assert.Equal(expected.Count, chat.Count);
-        for (int i = 0; i < expected.Count; i++)
-        {
-            var expectedMessage = expected[i];
-            var chatMessage = chat[i];
-
-            Assert.Equal(expectedMessage.Role, chatMessage.Role);
-            Assert.Equal(expectedMessage.Text, chatMessage.Text);
-            Assert.Equal(expectedMessage.GetType(), chatMessage.GetType());
-
-            Assert.Equal(expectedMessage.Contents.Count, chatMessage.Contents.Count);
-            for (int j = 0; j < expectedMessage.Contents.Count; j++)
-            {
-                var expectedItem = expectedMessage.Contents[j];
-                var chatItem = chatMessage.Contents[j];
-
-                Assert.Equal(expectedItem.GetType(), chatItem.GetType());
-                Assert.Equal(expectedItem.ToString(), chatItem.ToString());
-                if (expectedItem is FunctionCallContent expectedFunctionCall)
-                {
-                    var chatFunctionCall = (FunctionCallContent)chatItem;
-                    Assert.Equal(expectedFunctionCall.Name, chatFunctionCall.Name);
-                    AssertExtensions.EqualFunctionCallParameters(expectedFunctionCall.Arguments, chatFunctionCall.Arguments);
-                }
-                else if (expectedItem is FunctionResultContent expectedFunctionResult)
-                {
-                    var chatFunctionResult = (FunctionResultContent)chatItem;
-                    AssertExtensions.EqualFunctionCallResults(expectedFunctionResult.Result, chatFunctionResult.Result);
-                }
-            }
-        }
+        AssertExtensions.EqualMessageLists(expected, chat);
 
         // Usage should be aggregated over all responses, including AdditionalUsage
         var actualUsage = result.Usage!;
@@ -1325,38 +1294,8 @@ private static async Task<List<ChatMessage>> InvokeAndAssertStreamingAsync(
         chat.AddRange(result.Messages);
 
         expected ??= plan;
-        Assert.Equal(expected.Count, chat.Count);
-        for (int i = 0; i < expected.Count; i++)
-        {
-            var expectedMessage = expected[i];
-            var chatMessage = chat[i];
-
-            Assert.Equal(expectedMessage.Role, chatMessage.Role);
-            Assert.Equal(expectedMessage.Text, chatMessage.Text);
-            Assert.Equal(expectedMessage.GetType(), chatMessage.GetType());
-
-            Assert.Equal(expectedMessage.Contents.Count, chatMessage.Contents.Count);
-            for (int j = 0; j < expectedMessage.Contents.Count; j++)
-            {
-                var expectedItem = expectedMessage.Contents[j];
-                var chatItem = chatMessage.Contents[j];
-
-                Assert.Equal(expectedItem.GetType(), chatItem.GetType());
-                Assert.Equal(expectedItem.ToString(), chatItem.ToString());
-                if (expectedItem is FunctionCallContent expectedFunctionCall)
-                {
-                    var chatFunctionCall = (FunctionCallContent)chatItem;
-                    Assert.Equal(expectedFunctionCall.Name, chatFunctionCall.Name);
-                    AssertExtensions.EqualFunctionCallParameters(expectedFunctionCall.Arguments, chatFunctionCall.Arguments);
-                }
-                else if (expectedItem is FunctionResultContent expectedFunctionResult)
-                {
-                    var chatFunctionResult = (FunctionResultContent)chatItem;
-                    AssertExtensions.EqualFunctionCallResults(expectedFunctionResult.Result, chatFunctionResult.Result);
-                }
-            }
-        }
 
+        AssertExtensions.EqualMessageLists(expected, chat);
         return chat;
     }
 
@@ -1368,24 +1307,4 @@ private static async IAsyncEnumerable<T> YieldAsync<T>(params IEnumerable<T> ite
             yield return item;
         }
     }
-
-    private sealed class EnumeratedOnceEnumerable<T>(IEnumerable<T> items) : IEnumerable<T>
-    {
-        private int _iterated;
-
-        public IEnumerator<T> GetEnumerator()
-        {
-            if (Interlocked.Exchange(ref _iterated, 1) != 0)
-            {
-                throw new InvalidOperationException("This enumerable can only be enumerated once.");
-            }
-
-            foreach (var item in items)
-            {
-                yield return item;
-            }
-        }
-
-        IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
-    }
 }
diff --git a/test/Libraries/Microsoft.Extensions.AI.Tests/EnumeratedOnceEnumerable.cs b/test/Libraries/Microsoft.Extensions.AI.Tests/EnumeratedOnceEnumerable.cs
new file mode 100644
index 00000000000..84e0ba9ab61
--- /dev/null
+++ b/test/Libraries/Microsoft.Extensions.AI.Tests/EnumeratedOnceEnumerable.cs
@@ -0,0 +1,29 @@
+// 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;
+using System.Collections.Generic;
+using System.Threading;
+
+namespace Microsoft.Extensions.AI;
+
+internal sealed class EnumeratedOnceEnumerable<T>(IEnumerable<T> items) : IEnumerable<T>
+{
+    private int _iterated;
+
+    public IEnumerator<T> GetEnumerator()
+    {
+        if (Interlocked.Exchange(ref _iterated, 1) != 0)
+        {
+            throw new InvalidOperationException("This enumerable can only be enumerated once.");
+        }
+
+        foreach (var item in items)
+        {
+            yield return item;
+        }
+    }
+
+    IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
+}

From aae2551607e3bd1ecade43bfb1ca73df6d8f3331 Mon Sep 17 00:00:00 2001
From: Stephen Toub <stoub@microsoft.com>
Date: Sat, 6 Sep 2025 13:41:06 -0400
Subject: [PATCH 4/8] Update to OpenAI 2.4.0 (#6777)

---
 eng/packages/General.props                    |   2 +-
 eng/packages/TestOnly.props                   |   2 +-
 .../CHANGELOG.md                              |   1 +
 ...icrosoftExtensionsAIResponsesExtensions.cs |   2 +-
 .../OpenAIAssistantsChatClient.cs             |  11 +-
 .../OpenAIChatClient.cs                       |  14 +--
 .../OpenAIEmbeddingGenerator.cs               |  25 +---
 .../OpenAIImageGenerator.cs                   |  17 +--
 .../OpenAIResponsesChatClient.cs              | 110 ++++++++----------
 .../OpenAISpeechToTextClient.cs               |  14 +--
 .../ChatClientIntegrationTests.cs             |   6 +-
 .../OpenAIChatClientTests.cs                  |  18 ---
 .../OpenAIResponseClientIntegrationTests.cs   |   2 +-
 .../OpenAIResponseClientTests.cs              |  89 ++++++++++----
 14 files changed, 136 insertions(+), 177 deletions(-)

diff --git a/eng/packages/General.props b/eng/packages/General.props
index 253fb51ce1b..b7066789238 100644
--- a/eng/packages/General.props
+++ b/eng/packages/General.props
@@ -16,7 +16,7 @@
     <PackageVersion Include="Microsoft.ML.Tokenizers" Version="$(MicrosoftMLTokenizersVersion)" />
     <PackageVersion Include="Newtonsoft.Json" Version="13.0.3" />
     <PackageVersion Include="OllamaSharp" Version="5.1.9" />
-    <PackageVersion Include="OpenAI" Version="2.3.0" />
+    <PackageVersion Include="OpenAI" Version="2.4.0" />
     <PackageVersion Include="Polly" Version="8.4.2" />
     <PackageVersion Include="Polly.Core" Version="8.4.2" />
     <PackageVersion Include="Polly.Extensions" Version="8.4.2" />
diff --git a/eng/packages/TestOnly.props b/eng/packages/TestOnly.props
index dcfc7c03525..d8748a4ae9c 100644
--- a/eng/packages/TestOnly.props
+++ b/eng/packages/TestOnly.props
@@ -2,7 +2,7 @@
 <Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup>
     <PackageVersion Include="AutoFixture.AutoMoq" Version="4.17.0" />
-    <PackageVersion Include="Azure.AI.OpenAI" Version="2.3.0-beta.1" />
+    <PackageVersion Include="Azure.AI.OpenAI" Version="2.3.0-beta.2" />
     <PackageVersion Include="autofixture" Version="4.17.0" />
     <PackageVersion Include="BenchmarkDotNet" Version="0.13.5" />
     <PackageVersion Include="AwesomeAssertions" Version="8.0.2" />
diff --git a/src/Libraries/Microsoft.Extensions.AI.OpenAI/CHANGELOG.md b/src/Libraries/Microsoft.Extensions.AI.OpenAI/CHANGELOG.md
index 1c1c175ccd4..15859a5744d 100644
--- a/src/Libraries/Microsoft.Extensions.AI.OpenAI/CHANGELOG.md
+++ b/src/Libraries/Microsoft.Extensions.AI.OpenAI/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 - Updated tool mappings to recognize any `AIFunctionDeclaration`.
 - Updated to accommodate the additions in `Microsoft.Extensions.AI.Abstractions`.
+- Updated to depend on OpenAI 2.4.0
 
 ## 9.8.0-preview.1.25412.6
 
diff --git a/src/Libraries/Microsoft.Extensions.AI.OpenAI/MicrosoftExtensionsAIResponsesExtensions.cs b/src/Libraries/Microsoft.Extensions.AI.OpenAI/MicrosoftExtensionsAIResponsesExtensions.cs
index d6b290f431b..51df2653695 100644
--- a/src/Libraries/Microsoft.Extensions.AI.OpenAI/MicrosoftExtensionsAIResponsesExtensions.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.OpenAI/MicrosoftExtensionsAIResponsesExtensions.cs
@@ -18,7 +18,7 @@ public static class MicrosoftExtensionsAIResponsesExtensions
     /// <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 AIFunctionDeclaration function) =>
+    public static FunctionTool AsOpenAIResponseTool(this AIFunctionDeclaration function) =>
         OpenAIResponsesChatClient.ToResponseTool(Throw.IfNull(function));
 
     /// <summary>Creates a sequence of OpenAI <see cref="ResponseItem"/> instances from the specified input messages.</summary>
diff --git a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIAssistantsChatClient.cs b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIAssistantsChatClient.cs
index 01b78994f38..424185db887 100644
--- a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIAssistantsChatClient.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIAssistantsChatClient.cs
@@ -4,7 +4,6 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using System.Reflection;
 using System.Runtime.CompilerServices;
 using System.Text;
 using System.Text.Json;
@@ -50,17 +49,9 @@ public OpenAIAssistantsChatClient(AssistantClient assistantClient, string assist
     {
         _client = Throw.IfNull(assistantClient);
         _assistantId = Throw.IfNullOrWhitespace(assistantId);
-
         _defaultThreadId = defaultThreadId;
 
-        // https://github.com/openai/openai-dotnet/issues/215
-        // The endpoint isn't currently exposed, so use reflection to get at it, temporarily. Once packages
-        // implement the abstractions directly rather than providing adapters on top of the public APIs,
-        // the package can provide such implementations separate from what's exposed in the public API.
-        Uri providerUrl = typeof(AssistantClient).GetField("_endpoint", BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance)
-            ?.GetValue(assistantClient) as Uri ?? OpenAIClientExtensions.DefaultOpenAIEndpoint;
-
-        _metadata = new("openai", providerUrl);
+        _metadata = new("openai", assistantClient.Endpoint);
     }
 
     /// <summary>Initializes a new instance of the <see cref="OpenAIAssistantsChatClient"/> class for the specified <see cref="AssistantClient"/>.</summary>
diff --git a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIChatClient.cs b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIChatClient.cs
index 415aef5901e..8c65766413f 100644
--- a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIChatClient.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIChatClient.cs
@@ -4,7 +4,6 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using System.Reflection;
 using System.Runtime.CompilerServices;
 using System.Text;
 using System.Text.Json;
@@ -37,18 +36,9 @@ internal sealed class OpenAIChatClient : IChatClient
     /// <exception cref="ArgumentNullException"><paramref name="chatClient"/> is <see langword="null"/>.</exception>
     public OpenAIChatClient(ChatClient chatClient)
     {
-        _ = Throw.IfNull(chatClient);
+        _chatClient = Throw.IfNull(chatClient);
 
-        _chatClient = chatClient;
-
-        // https://github.com/openai/openai-dotnet/issues/215
-        // The endpoint and model aren't currently exposed, so use reflection to get at them, temporarily. Once packages
-        // implement the abstractions directly rather than providing adapters on top of the public APIs,
-        // the package can provide such implementations separate from what's exposed in the public API.
-        Uri providerUrl = typeof(ChatClient).GetField("_endpoint", BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance)
-            ?.GetValue(chatClient) as Uri ?? OpenAIClientExtensions.DefaultOpenAIEndpoint;
-
-        _metadata = new("openai", providerUrl, _chatClient.Model);
+        _metadata = new("openai", chatClient.Endpoint, _chatClient.Model);
     }
 
     /// <inheritdoc />
diff --git a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIEmbeddingGenerator.cs b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIEmbeddingGenerator.cs
index 84f3c5966b8..dbe9bf10237 100644
--- a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIEmbeddingGenerator.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIEmbeddingGenerator.cs
@@ -4,7 +4,6 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using System.Reflection;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Shared.Diagnostics;
@@ -18,9 +17,6 @@ namespace Microsoft.Extensions.AI;
 /// <summary>An <see cref="IEmbeddingGenerator{String, Embedding}"/> for an OpenAI <see cref="EmbeddingClient"/>.</summary>
 internal sealed class OpenAIEmbeddingGenerator : IEmbeddingGenerator<string, Embedding<float>>
 {
-    /// <summary>Default OpenAI endpoint.</summary>
-    private const string DefaultOpenAIEndpoint = "https://api.openai.com/v1";
-
     /// <summary>Metadata about the embedding generator.</summary>
     private readonly EmbeddingGeneratorMetadata _metadata;
 
@@ -37,24 +33,15 @@ internal sealed class OpenAIEmbeddingGenerator : IEmbeddingGenerator<string, Emb
     /// <exception cref="ArgumentOutOfRangeException"><paramref name="defaultModelDimensions"/> is not positive.</exception>
     public OpenAIEmbeddingGenerator(EmbeddingClient embeddingClient, int? defaultModelDimensions = null)
     {
-        _ = Throw.IfNull(embeddingClient);
+        _embeddingClient = Throw.IfNull(embeddingClient);
+        _dimensions = defaultModelDimensions;
+
         if (defaultModelDimensions < 1)
         {
             Throw.ArgumentOutOfRangeException(nameof(defaultModelDimensions), "Value must be greater than 0.");
         }
 
-        _embeddingClient = embeddingClient;
-        _dimensions = defaultModelDimensions;
-
-        // https://github.com/openai/openai-dotnet/issues/215
-        // The endpoint and model aren't currently exposed, so use reflection to get at them, temporarily. Once packages
-        // implement the abstractions directly rather than providing adapters on top of the public APIs,
-        // the package can provide such implementations separate from what's exposed in the public API.
-        string providerUrl = (typeof(EmbeddingClient).GetField("_endpoint", BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance)
-            ?.GetValue(embeddingClient) as Uri)?.ToString() ??
-            DefaultOpenAIEndpoint;
-
-        _metadata = CreateMetadata("openai", providerUrl, _embeddingClient.Model, defaultModelDimensions);
+        _metadata = new("openai", embeddingClient.Endpoint, _embeddingClient.Model, defaultModelDimensions);
     }
 
     /// <inheritdoc />
@@ -98,10 +85,6 @@ void IDisposable.Dispose()
             null;
     }
 
-    /// <summary>Creates the <see cref="EmbeddingGeneratorMetadata"/> for this instance.</summary>
-    private static EmbeddingGeneratorMetadata CreateMetadata(string providerName, string providerUrl, string? defaultModelId, int? defaultModelDimensions) =>
-        new(providerName, Uri.TryCreate(providerUrl, UriKind.Absolute, out Uri? providerUri) ? providerUri : null, defaultModelId, defaultModelDimensions);
-
     /// <summary>Converts an extensions options instance to an OpenAI options instance.</summary>
     private OpenAI.Embeddings.EmbeddingGenerationOptions ToOpenAIOptions(EmbeddingGenerationOptions? options)
     {
diff --git a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIImageGenerator.cs b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIImageGenerator.cs
index fe1cb399e0d..b2ceb5cb317 100644
--- a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIImageGenerator.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIImageGenerator.cs
@@ -45,18 +45,9 @@ internal sealed class OpenAIImageGenerator : IImageGenerator
     /// <exception cref="ArgumentNullException"><paramref name="imageClient"/> is <see langword="null"/>.</exception>
     public OpenAIImageGenerator(ImageClient imageClient)
     {
-        _ = Throw.IfNull(imageClient);
+        _imageClient = Throw.IfNull(imageClient);
 
-        _imageClient = imageClient;
-
-        // https://github.com/openai/openai-dotnet/issues/215
-        // The endpoint and model aren't currently exposed, so use reflection to get at them, temporarily. Once packages
-        // implement the abstractions directly rather than providing adapters on top of the public APIs,
-        // the package can provide such implementations separate from what's exposed in the public API.
-        Uri providerUrl = typeof(ImageClient).GetField("_endpoint", BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance)
-            ?.GetValue(imageClient) as Uri ?? OpenAIClientExtensions.DefaultOpenAIEndpoint;
-
-        _metadata = new("openai", providerUrl, _imageClient.Model);
+        _metadata = new("openai", imageClient.Endpoint, _imageClient.Model);
     }
 
     /// <inheritdoc />
@@ -143,7 +134,7 @@ private static ImageGenerationResponse ToImageGenerationResponse(GeneratedImageC
 
         // OpenAI doesn't expose the content type, so we need to read from the internal JSON representation.
         // https://github.com/openai/openai-dotnet/issues/561
-        IDictionary<string, BinaryData>? additionalRawData = typeof(GeneratedImageCollection)
+        var additionalRawData = typeof(GeneratedImageCollection)
             .GetProperty("SerializedAdditionalRawData", BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance)
             ?.GetValue(generatedImages) as IDictionary<string, BinaryData>;
 
@@ -154,7 +145,7 @@ private static ImageGenerationResponse ToImageGenerationResponse(GeneratedImageC
             contentType = $"image/{outputFormatString}";
         }
 
-        List<AIContent> contents = new();
+        List<AIContent> contents = [];
 
         foreach (GeneratedImage image in generatedImages)
         {
diff --git a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponsesChatClient.cs b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponsesChatClient.cs
index b5d3c09de32..0acfef52eb0 100644
--- a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponsesChatClient.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponsesChatClient.cs
@@ -8,7 +8,6 @@
 using System.Linq;
 using System.Reflection;
 using System.Runtime.CompilerServices;
-using System.Text;
 using System.Text.Json;
 using System.Threading;
 using System.Threading.Tasks;
@@ -47,16 +46,12 @@ public OpenAIResponsesChatClient(OpenAIResponseClient responseClient)
 
         _responseClient = responseClient;
 
-        // https://github.com/openai/openai-dotnet/issues/215
-        // The endpoint and model aren't currently exposed, so use reflection to get at them, temporarily. Once packages
-        // implement the abstractions directly rather than providing adapters on top of the public APIs,
-        // the package can provide such implementations separate from what's exposed in the public API.
-        Uri providerUrl = typeof(OpenAIResponseClient).GetField("_endpoint", BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance)
-            ?.GetValue(responseClient) as Uri ?? OpenAIClientExtensions.DefaultOpenAIEndpoint;
+        // https://github.com/openai/openai-dotnet/issues/662
+        // Update to avoid reflection once OpenAIResponseClient.Model is exposed publicly.
         string? model = typeof(OpenAIResponseClient).GetField("_model", BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance)
             ?.GetValue(responseClient) as string;
 
-        _metadata = new("openai", providerUrl, model);
+        _metadata = new("openai", responseClient.Endpoint, model);
     }
 
     /// <inheritdoc />
@@ -204,7 +199,7 @@ internal static async IAsyncEnumerable<ChatResponseUpdate> FromOpenAIStreamingRe
         string? lastMessageId = null;
         ChatRole? lastRole = null;
         Dictionary<int, MessageResponseItem> outputIndexToMessages = [];
-        Dictionary<int, FunctionCallInfo>? functionCallInfos = null;
+        Dictionary<int, FunctionCallResponseItem>? functionCallItems = null;
 
         await foreach (var streamingUpdate in streamingResponseUpdates.WithCancellation(cancellationToken).ConfigureAwait(false))
         {
@@ -234,7 +229,7 @@ ChatResponseUpdate CreateUpdate(AIContent? content = null) =>
                     var update = CreateUpdate(ToUsageDetails(completedUpdate.Response) is { } usage ? new UsageContent(usage) : null);
                     update.FinishReason =
                         ToFinishReason(completedUpdate.Response?.IncompleteStatusDetails?.Reason) ??
-                        (functionCallInfos is not null ? ChatFinishReason.ToolCalls :
+                        (functionCallItems is not null ? ChatFinishReason.ToolCalls :
                         ChatFinishReason.Stop);
                     yield return update;
                     break;
@@ -248,7 +243,7 @@ ChatResponseUpdate CreateUpdate(AIContent? content = null) =>
                             break;
 
                         case FunctionCallResponseItem fcri:
-                            (functionCallInfos ??= [])[outputItemAddedUpdate.OutputIndex] = new(fcri);
+                            (functionCallItems ??= [])[outputItemAddedUpdate.OutputIndex] = fcri;
                             break;
                     }
 
@@ -283,28 +278,18 @@ ChatResponseUpdate CreateUpdate(AIContent? content = null) =>
                     break;
                 }
 
-                case StreamingResponseFunctionCallArgumentsDeltaUpdate functionCallArgumentsDeltaUpdate:
-                {
-                    if (functionCallInfos?.TryGetValue(functionCallArgumentsDeltaUpdate.OutputIndex, out FunctionCallInfo? callInfo) is true)
-                    {
-                        _ = (callInfo.Arguments ??= new()).Append(functionCallArgumentsDeltaUpdate.Delta);
-                    }
-
-                    goto default;
-                }
-
                 case StreamingResponseFunctionCallArgumentsDoneUpdate functionCallOutputDoneUpdate:
                 {
-                    if (functionCallInfos?.TryGetValue(functionCallOutputDoneUpdate.OutputIndex, out FunctionCallInfo? callInfo) is true)
+                    if (functionCallItems?.TryGetValue(functionCallOutputDoneUpdate.OutputIndex, out FunctionCallResponseItem? callInfo) is true)
                     {
-                        _ = functionCallInfos.Remove(functionCallOutputDoneUpdate.OutputIndex);
+                        _ = functionCallItems.Remove(functionCallOutputDoneUpdate.OutputIndex);
 
                         var fcc = OpenAIClientExtensions.ParseCallContent(
-                            callInfo.Arguments?.ToString() ?? string.Empty,
-                            callInfo.ResponseItem.CallId,
-                            callInfo.ResponseItem.FunctionName);
+                            functionCallOutputDoneUpdate.FunctionArguments.ToString(),
+                            callInfo.CallId,
+                            callInfo.FunctionName);
 
-                        lastMessageId = callInfo.ResponseItem.Id;
+                        lastMessageId = callInfo.Id;
                         lastRole = ChatRole.Assistant;
 
                         yield return CreateUpdate(fcc);
@@ -329,18 +314,16 @@ ChatResponseUpdate CreateUpdate(AIContent? content = null) =>
                     });
                     break;
 
-                default:
-                {
-                    if (streamingUpdate.GetType() == _internalResponseReasoningSummaryTextDeltaEventType &&
-                        _summaryTextDeltaProperty?.GetValue(streamingUpdate) is string delta)
-                    {
-                        yield return CreateUpdate(new TextReasoningContent(delta));
-                        break;
-                    }
+                // Replace with public StreamingResponseReasoningSummaryTextDelta when available
+                case StreamingResponseUpdate when
+                        streamingUpdate.GetType() == _internalResponseReasoningSummaryTextDeltaEventType &&
+                        _summaryTextDeltaProperty?.GetValue(streamingUpdate) is string delta:
+                    yield return CreateUpdate(new TextReasoningContent(delta));
+                    break;
 
+                default:
                     yield return CreateUpdate();
                     break;
-                }
             }
         }
     }
@@ -351,7 +334,7 @@ void IDisposable.Dispose()
         // Nothing to dispose. Implementation required for the IChatClient interface.
     }
 
-    internal static ResponseTool ToResponseTool(AIFunctionDeclaration aiFunction, ChatOptions? options = null)
+    internal static FunctionTool ToResponseTool(AIFunctionDeclaration aiFunction, ChatOptions? options = null)
     {
         bool? strict =
             OpenAIClientExtensions.HasStrict(aiFunction.AdditionalProperties) ??
@@ -359,9 +342,9 @@ internal static ResponseTool ToResponseTool(AIFunctionDeclaration aiFunction, Ch
 
         return ResponseTool.CreateFunctionTool(
             aiFunction.Name,
-            aiFunction.Description,
             OpenAIClientExtensions.ToOpenAIFunctionParameters(aiFunction, strict),
-            strict ?? false);
+            strict,
+            aiFunction.Description);
     }
 
     /// <summary>Creates a <see cref="ChatRole"/> from a <see cref="MessageRole"/>.</summary>
@@ -419,17 +402,17 @@ private ResponseCreationOptions ToOpenAIResponseCreationOptions(ChatOptions? opt
                         break;
 
                     case HostedWebSearchTool webSearchTool:
-                        WebSearchUserLocation? location = null;
-                        if (webSearchTool.AdditionalProperties.TryGetValue(nameof(WebSearchUserLocation), out object? objLocation))
+                        WebSearchToolLocation? location = null;
+                        if (webSearchTool.AdditionalProperties.TryGetValue(nameof(WebSearchToolLocation), out object? objLocation))
                         {
-                            location = objLocation as WebSearchUserLocation;
+                            location = objLocation as WebSearchToolLocation;
                         }
 
-                        WebSearchContextSize? size = null;
-                        if (webSearchTool.AdditionalProperties.TryGetValue(nameof(WebSearchContextSize), out object? objSize) &&
-                            objSize is WebSearchContextSize)
+                        WebSearchToolContextSize? size = null;
+                        if (webSearchTool.AdditionalProperties.TryGetValue(nameof(WebSearchToolContextSize), out object? objSize) &&
+                            objSize is WebSearchToolContextSize)
                         {
-                            size = (WebSearchContextSize)objSize;
+                            size = (WebSearchToolContextSize)objSize;
                         }
 
                         result.Tools.Add(ResponseTool.CreateWebSearchTool(location, size));
@@ -690,14 +673,29 @@ private static void PopulateAnnotations(ResponseContentPart source, AIContent de
         {
             foreach (var ota in source.OutputTextAnnotations)
             {
-                (destination.Annotations ??= []).Add(new CitationAnnotation
+                CitationAnnotation ca = new()
                 {
                     RawRepresentation = ota,
-                    AnnotatedRegions = [new TextSpanAnnotatedRegion { StartIndex = ota.UriCitationStartIndex, EndIndex = ota.UriCitationEndIndex }],
-                    Title = ota.UriCitationTitle,
-                    Url = ota.UriCitationUri,
-                    FileId = ota.FileCitationFileId ?? ota.FilePathFileId,
-                });
+                };
+
+                switch (ota)
+                {
+                    case UriCitationMessageAnnotation ucma:
+                        ca.AnnotatedRegions = [new TextSpanAnnotatedRegion { StartIndex = ucma.StartIndex, EndIndex = ucma.EndIndex }];
+                        ca.Title = ucma.Title;
+                        ca.Url = ucma.Uri;
+                        break;
+
+                    case FilePathMessageAnnotation fpma:
+                        ca.FileId = fpma.FileId;
+                        break;
+
+                    case FileCitationMessageAnnotation fcma:
+                        ca.FileId = fcma.FileId;
+                        break;
+                }
+
+                (destination.Annotations ??= []).Add(ca);
             }
         }
     }
@@ -747,12 +745,4 @@ private static List<ResponseContentPart> ToResponseContentParts(IList<AIContent>
 
         return parts;
     }
-
-    /// <summary>POCO representing function calling info.</summary>
-    /// <remarks>Used to concatenation information for a single function call from across multiple streaming updates.</remarks>
-    private sealed class FunctionCallInfo(FunctionCallResponseItem item)
-    {
-        public readonly FunctionCallResponseItem ResponseItem = item;
-        public StringBuilder? Arguments;
-    }
 }
diff --git a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAISpeechToTextClient.cs b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAISpeechToTextClient.cs
index 2e2503335f3..06051a54c26 100644
--- a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAISpeechToTextClient.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAISpeechToTextClient.cs
@@ -5,7 +5,6 @@
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.IO;
-using System.Reflection;
 using System.Runtime.CompilerServices;
 using System.Threading;
 using System.Threading.Tasks;
@@ -37,18 +36,9 @@ internal sealed class OpenAISpeechToTextClient : ISpeechToTextClient
     /// <param name="audioClient">The underlying client.</param>
     public OpenAISpeechToTextClient(AudioClient audioClient)
     {
-        _ = Throw.IfNull(audioClient);
+        _audioClient = Throw.IfNull(audioClient);
 
-        _audioClient = audioClient;
-
-        // https://github.com/openai/openai-dotnet/issues/215
-        // The endpoint and model aren't currently exposed, so use reflection to get at them, temporarily. Once packages
-        // implement the abstractions directly rather than providing adapters on top of the public APIs,
-        // the package can provide such implementations separate from what's exposed in the public API.
-        Uri providerUrl = typeof(AudioClient).GetField("_endpoint", BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance)
-            ?.GetValue(audioClient) as Uri ?? OpenAIClientExtensions.DefaultOpenAIEndpoint;
-
-        _metadata = new("openai", providerUrl, _audioClient.Model);
+        _metadata = new("openai", audioClient.Endpoint, _audioClient.Model);
     }
 
     /// <inheritdoc />
diff --git a/test/Libraries/Microsoft.Extensions.AI.Integration.Tests/ChatClientIntegrationTests.cs b/test/Libraries/Microsoft.Extensions.AI.Integration.Tests/ChatClientIntegrationTests.cs
index c87625cf143..448de8d11df 100644
--- a/test/Libraries/Microsoft.Extensions.AI.Integration.Tests/ChatClientIntegrationTests.cs
+++ b/test/Libraries/Microsoft.Extensions.AI.Integration.Tests/ChatClientIntegrationTests.cs
@@ -942,7 +942,7 @@ public virtual async Task OpenTelemetry_CanEmitTracesAndMetrics()
 
         var activity = Assert.Single(activities);
         Assert.StartsWith("chat", activity.DisplayName);
-        Assert.StartsWith("http", (string)activity.GetTagItem("server.address")!);
+        Assert.Contains(".", (string)activity.GetTagItem("server.address")!);
         Assert.Equal(chatClient.GetService<ChatClientMetadata>()?.ProviderUri?.Port, (int)activity.GetTagItem("server.port")!);
         Assert.NotNull(activity.Id);
         Assert.NotEmpty(activity.Id);
@@ -1276,7 +1276,7 @@ public virtual async Task SummarizingChatReducer_Streaming()
             new(ChatRole.Assistant, "That sounds impactful! AI in education has so much potential."),
             new(ChatRole.User, "Yes, we focus on personalized learning experiences."),
             new(ChatRole.Assistant, "Personalized learning is the future of education!"),
-            new(ChatRole.User, "What's my name and profession?")
+            new(ChatRole.User, "Was anyone named in the conversation? Provide their name and job.")
         ];
 
         StringBuilder sb = new();
@@ -1296,7 +1296,7 @@ public virtual async Task SummarizingChatReducer_Streaming()
                 Assert.Contains("Bob", m.Text);
             },
             m => Assert.StartsWith("Personalized learning", m.Text, StringComparison.Ordinal),
-            m => Assert.Equal("What's my name and profession?", m.Text));
+            m => Assert.Equal("Was anyone named in the conversation? Provide their name and job.", m.Text));
 
         string responseText = sb.ToString();
         Assert.Contains("Bob", responseText);
diff --git a/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIChatClientTests.cs b/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIChatClientTests.cs
index 640dab54f8e..bdf3b2e7c0a 100644
--- a/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIChatClientTests.cs
+++ b/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIChatClientTests.cs
@@ -8,8 +8,6 @@
 using System.ComponentModel;
 using System.Linq;
 using System.Net.Http;
-using System.Text.Json;
-using System.Text.Json.Serialization;
 using System.Threading.Tasks;
 using Microsoft.Extensions.Caching.Distributed;
 using Microsoft.Extensions.Caching.Memory;
@@ -655,22 +653,6 @@ public async Task ChatOptions_Overwrite_NullPropertiesInRawRepresentation_Stream
         Assert.Equal("Hello! How can I assist you today?", responseText);
     }
 
-    /// <summary>Used to create the JSON payload for an OpenAI chat tool description.</summary>
-    internal sealed class ChatToolJson
-    {
-        [JsonPropertyName("type")]
-        public string Type { get; set; } = "object";
-
-        [JsonPropertyName("required")]
-        public HashSet<string> Required { get; set; } = [];
-
-        [JsonPropertyName("properties")]
-        public Dictionary<string, JsonElement> Properties { get; set; } = [];
-
-        [JsonPropertyName("additionalProperties")]
-        public bool AdditionalProperties { get; set; }
-    }
-
     [Fact]
     public async Task StronglyTypedOptions_AllSent()
     {
diff --git a/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIResponseClientIntegrationTests.cs b/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIResponseClientIntegrationTests.cs
index 630af9e34b0..007e86288f5 100644
--- a/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIResponseClientIntegrationTests.cs
+++ b/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIResponseClientIntegrationTests.cs
@@ -27,7 +27,7 @@ public async Task UseWebSearch_AnnotationsReflectResults()
         SkipIfNotEnabled();
 
         var response = await ChatClient.GetResponseAsync(
-            "Write a paragraph about the three most recent blog posts on the .NET blog. Cite your sources.",
+            "Write a paragraph about .NET based on at least three recent news articles. Cite your sources.",
             new() { Tools = [new HostedWebSearchTool()] });
 
         ChatMessage m = Assert.Single(response.Messages);
diff --git a/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIResponseClientTests.cs b/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIResponseClientTests.cs
index ca71aee550f..014fae0d39f 100644
--- a/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIResponseClientTests.cs
+++ b/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIResponseClientTests.cs
@@ -8,7 +8,6 @@
 using System.ComponentModel;
 using System.Linq;
 using System.Net.Http;
-using System.Text.Json;
 using System.Threading.Tasks;
 using Microsoft.Extensions.Caching.Distributed;
 using Microsoft.Extensions.Caching.Memory;
@@ -543,20 +542,70 @@ public async Task ChatOptions_DoNotOverwrite_NotNullPropertiesInRawRepresentatio
     {
         const string Input = """
             {
-              "input":[{"type":"message","role":"user","content":[{"type":"input_text","text":"hello"}]}],
-              "model":"gpt-4o-mini",
-              "max_output_tokens":10,
-              "previous_response_id":"resp_42",
-              "top_p":0.5,
-              "temperature":0.5,
-              "parallel_tool_calls":true,
-              "text": {"format": {"type": "text"}
-            },
-              "tool_choice":"auto",
-              "tools":[
-                {"description":"Gets the age of the specified person.","name":"GetPersonAge","parameters":{"additionalProperties":false,"properties":{"personName":{"description":"The person whose age is being requested","type":"string"}},"required":["personName"],"type":"object"},"strict":false,"type":"function"},
-                {"description":"Gets the age of the specified person.","name":"GetPersonAge","parameters":{"additionalProperties":false,"properties":{"personName":{"description":"The person whose age is being requested","type":"string"}},"required":["personName"],"type":"object"},"strict":false,"type":"function"}
-              ]
+                "temperature": 0.5,
+                "top_p": 0.5,
+                "previous_response_id": "resp_42",
+                "model": "gpt-4o-mini",
+                "max_output_tokens": 10,
+                "text": {
+                    "format": {
+                        "type": "text"
+                    }
+                },
+                "tools": [
+                    {
+                        "type": "function",
+                        "name": "GetPersonAge",
+                        "description": "Gets the age of the specified person.",
+                        "parameters": {
+                            "type": "object",
+                            "required": [
+                                "personName"
+                            ],
+                            "properties": {
+                                "personName": {
+                                    "description": "The person whose age is being requested",
+                                    "type": "string"
+                                }
+                            },
+                            "additionalProperties": false
+                        },
+                        "strict": null
+                    },
+                    {
+                        "type": "function",
+                        "name": "GetPersonAge",
+                        "description": "Gets the age of the specified person.",
+                        "parameters": {
+                            "type": "object",
+                            "required": [
+                                "personName"
+                            ],
+                            "properties": {
+                                "personName": {
+                                    "description": "The person whose age is being requested",
+                                    "type": "string"
+                                }
+                            },
+                            "additionalProperties": false
+                        },
+                        "strict": null
+                    }
+                ],
+                "tool_choice": "auto",
+                "input": [
+                    {
+                        "type": "message",
+                        "role": "user",
+                        "content": [
+                            {
+                                "type": "input_text",
+                                "text": "hello"
+                            }
+                        ]
+                    }
+                ],
+                "parallel_tool_calls": true
             }
             """;
 
@@ -640,7 +689,7 @@ public async Task ChatOptions_DoNotOverwrite_NotNullPropertiesInRawRepresentatio
                         TextFormat = ResponseTextFormat.CreateTextFormat()
                     },
                 };
-                openAIOptions.Tools.Add(ToOpenAIResponseChatTool(tool));
+                openAIOptions.Tools.Add(tool.AsOpenAIResponseTool());
                 return openAIOptions;
             },
             ModelId = null,
@@ -775,14 +824,6 @@ public async Task MultipleOutputItems_NonStreaming()
         Assert.Equal(36, response.Usage.TotalTokenCount);
     }
 
-    /// <summary>Converts an Extensions function to an OpenAI response chat tool.</summary>
-    private static ResponseTool ToOpenAIResponseChatTool(AIFunction aiFunction)
-    {
-        var tool = JsonSerializer.Deserialize<OpenAIChatClientTests.ChatToolJson>(aiFunction.JsonSchema)!;
-        var functionParameters = BinaryData.FromBytes(JsonSerializer.SerializeToUtf8Bytes(tool));
-        return ResponseTool.CreateFunctionTool(aiFunction.Name, aiFunction.Description, functionParameters);
-    }
-
     private static IChatClient CreateResponseClient(HttpClient httpClient, string modelId) =>
         new OpenAIClient(
             new ApiKeyCredential("apikey"),

From b7fe7398d93b8e86884c21ca46c5a2ab80618753 Mon Sep 17 00:00:00 2001
From: Stephen Toub <stoub@microsoft.com>
Date: Sat, 6 Sep 2025 13:55:41 -0400
Subject: [PATCH 5/8] Factor ChatMessage.Role into ChatResponseUpdate
 coalescing logic (#6778)

If the role changes, consider it a new message.
---
 .../ChatCompletion/ChatResponseExtensions.cs  |  8 ++-
 .../ChatResponseUpdateExtensionsTests.cs      | 60 ++++++++++++++++++-
 2 files changed, 65 insertions(+), 3 deletions(-)

diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/ChatCompletion/ChatResponseExtensions.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/ChatCompletion/ChatResponseExtensions.cs
index e41368f115d..b9909857be2 100644
--- a/src/Libraries/Microsoft.Extensions.AI.Abstractions/ChatCompletion/ChatResponseExtensions.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/ChatCompletion/ChatResponseExtensions.cs
@@ -303,7 +303,7 @@ private static void FinalizeResponse(ChatResponse response)
     private static void ProcessUpdate(ChatResponseUpdate update, ChatResponse response)
     {
         // If there is no message created yet, or if the last update we saw had a different
-        // message ID than the newest update, create a new message.
+        // message ID or role than the newest update, create a new message.
         ChatMessage message;
         var isNewMessage = false;
         if (response.Messages.Count == 0)
@@ -316,6 +316,12 @@ private static void ProcessUpdate(ChatResponseUpdate update, ChatResponse respon
         {
             isNewMessage = true;
         }
+        else if (update.Role is { } updateRole
+            && response.Messages[response.Messages.Count - 1].Role is { } lastRole
+            && updateRole != lastRole)
+        {
+            isNewMessage = true;
+        }
 
         if (isNewMessage)
         {
diff --git a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/ChatCompletion/ChatResponseUpdateExtensionsTests.cs b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/ChatCompletion/ChatResponseUpdateExtensionsTests.cs
index 45a82542da8..5cfb7ace025 100644
--- a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/ChatCompletion/ChatResponseUpdateExtensionsTests.cs
+++ b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/ChatCompletion/ChatResponseUpdateExtensionsTests.cs
@@ -29,7 +29,7 @@ public async Task ToChatResponse_SuccessfullyCreatesResponse(bool useAsync)
         ChatResponseUpdate[] updates =
         [
             new(ChatRole.Assistant, "Hello") { ResponseId = "someResponse", MessageId = "12345", CreatedAt = new DateTimeOffset(1, 2, 3, 4, 5, 6, TimeSpan.Zero), ModelId = "model123" },
-            new(new("human"), ", ") { AuthorName = "Someone", AdditionalProperties = new() { ["a"] = "b" } },
+            new(ChatRole.Assistant, ", ") { AuthorName = "Someone", AdditionalProperties = new() { ["a"] = "b" } },
             new(null, "world!") { CreatedAt = new DateTimeOffset(2, 2, 3, 4, 5, 6, TimeSpan.Zero), ConversationId = "123", AdditionalProperties = new() { ["c"] = "d" } },
 
             new() { Contents = [new UsageContent(new() { InputTokenCount = 1, OutputTokenCount = 2 })] },
@@ -53,7 +53,7 @@ public async Task ToChatResponse_SuccessfullyCreatesResponse(bool useAsync)
 
         ChatMessage message = response.Messages.Single();
         Assert.Equal("12345", message.MessageId);
-        Assert.Equal(new ChatRole("human"), message.Role);
+        Assert.Equal(ChatRole.Assistant, message.Role);
         Assert.Equal("Someone", message.AuthorName);
         Assert.Null(message.AdditionalProperties);
 
@@ -65,6 +65,62 @@ public async Task ToChatResponse_SuccessfullyCreatesResponse(bool useAsync)
         Assert.Equal("Hello, world!", response.Text);
     }
 
+    [Theory]
+    [InlineData(false)]
+    [InlineData(true)]
+    public async Task ToChatResponse_RoleOrIdChangeDictatesMessageChange(bool useAsync)
+    {
+        ChatResponseUpdate[] updates =
+        [
+            new(null, "!") { MessageId = "1" },
+            new(ChatRole.Assistant, "a") { MessageId = "1" },
+            new(ChatRole.Assistant, "b") { MessageId = "2" },
+            new(ChatRole.User, "c") { MessageId = "2" },
+            new(ChatRole.User, "d") { MessageId = "2" },
+            new(ChatRole.Assistant, "e") { MessageId = "3" },
+            new(ChatRole.Tool, "f") { MessageId = "4" },
+            new(ChatRole.Tool, "g") { MessageId = "4" },
+            new(ChatRole.Tool, "h") { MessageId = "5" },
+            new(new("human"), "i") { MessageId = "6" },
+            new(new("human"), "j") { MessageId = "7" },
+            new(new("human"), "k") { MessageId = "7" },
+            new(null, "l") { MessageId = "7" },
+            new(null, "m") { MessageId = "8" },
+        ];
+
+        ChatResponse response = useAsync ?
+            updates.ToChatResponse() :
+            await YieldAsync(updates).ToChatResponseAsync();
+        Assert.Equal(9, response.Messages.Count);
+
+        Assert.Equal("!a", response.Messages[0].Text);
+        Assert.Equal(ChatRole.Assistant, response.Messages[0].Role);
+
+        Assert.Equal("b", response.Messages[1].Text);
+        Assert.Equal(ChatRole.Assistant, response.Messages[1].Role);
+
+        Assert.Equal("cd", response.Messages[2].Text);
+        Assert.Equal(ChatRole.User, response.Messages[2].Role);
+
+        Assert.Equal("e", response.Messages[3].Text);
+        Assert.Equal(ChatRole.Assistant, response.Messages[3].Role);
+
+        Assert.Equal("fg", response.Messages[4].Text);
+        Assert.Equal(ChatRole.Tool, response.Messages[4].Role);
+
+        Assert.Equal("h", response.Messages[5].Text);
+        Assert.Equal(ChatRole.Tool, response.Messages[5].Role);
+
+        Assert.Equal("i", response.Messages[6].Text);
+        Assert.Equal(new ChatRole("human"), response.Messages[6].Role);
+
+        Assert.Equal("jkl", response.Messages[7].Text);
+        Assert.Equal(new ChatRole("human"), response.Messages[7].Role);
+
+        Assert.Equal("m", response.Messages[8].Text);
+        Assert.Equal(ChatRole.Assistant, response.Messages[8].Role);
+    }
+
     [Theory]
     [InlineData(false)]
     [InlineData(true)]

From 66289793a78583a639c16527af9f211d815a28ef Mon Sep 17 00:00:00 2001
From: Stephen Toub <stoub@microsoft.com>
Date: Sat, 6 Sep 2025 18:51:58 -0400
Subject: [PATCH 6/8] Change OpenTelemetryChatClient/EmbeddingGenerator to log
 raw additional properties (#6776)

For historical reasons (based on older versions of the genai convention), we were mangling the key names. Now just use the key names as sourced from the dictionary, enabling a developer to more easily augment the spans with data of their choice.
---
 .../ChatCompletion/OpenTelemetryChatClient.cs | 34 ++++++-------------
 .../OpenTelemetryEmbeddingGenerator.cs        | 26 ++++----------
 .../OpenTelemetryConsts.cs                    |  4 ---
 .../OpenTelemetryChatClientTests.cs           |  8 ++---
 .../OpenTelemetryEmbeddingGeneratorTests.cs   |  8 ++---
 5 files changed, 25 insertions(+), 55 deletions(-)

diff --git a/src/Libraries/Microsoft.Extensions.AI/ChatCompletion/OpenTelemetryChatClient.cs b/src/Libraries/Microsoft.Extensions.AI/ChatCompletion/OpenTelemetryChatClient.cs
index 234e56a68bc..f9215060dea 100644
--- a/src/Libraries/Microsoft.Extensions.AI/ChatCompletion/OpenTelemetryChatClient.cs
+++ b/src/Libraries/Microsoft.Extensions.AI/ChatCompletion/OpenTelemetryChatClient.cs
@@ -364,20 +364,13 @@ private static string SerializeChatMessages(IEnumerable<ChatMessage> messages, C
                         }
                     }
 
-                    if (_providerName is not null)
+                    // Log all additional request options as raw values on the span.
+                    // Since AdditionalProperties has undefined meaning, we treat it as potentially sensitive data.
+                    if (EnableSensitiveData && options.AdditionalProperties is { } props)
                     {
-                        // Since AdditionalProperties has undefined meaning, we treat it as potentially sensitive data
-                        if (EnableSensitiveData && options.AdditionalProperties is { } props)
+                        foreach (KeyValuePair<string, object?> prop in props)
                         {
-                            // Log all additional request options as per-provider tags. This is non-normative, but it covers cases where
-                            // there's a per-provider specification in a best-effort manner (e.g. gen_ai.openai.request.service_tier),
-                            // and more generally cases where there's additional useful information to be logged.
-                            foreach (KeyValuePair<string, object?> prop in props)
-                            {
-                                _ = activity.AddTag(
-                                    OpenTelemetryConsts.GenAI.Request.PerProvider(_providerName, JsonNamingPolicy.SnakeCaseLower.ConvertName(prop.Key)),
-                                    prop.Value);
-                            }
+                            _ = activity.AddTag(prop.Key, prop.Value);
                         }
                     }
                 }
@@ -467,20 +460,13 @@ private void TraceResponse(
                     _ = activity.AddTag(OpenTelemetryConsts.GenAI.Usage.OutputTokens, (int)outputTokens);
                 }
 
-                if (_providerName is not null)
+                // Log all additional response properties as raw values on the span.
+                // Since AdditionalProperties has undefined meaning, we treat it as potentially sensitive data.
+                if (EnableSensitiveData && response.AdditionalProperties is { } props)
                 {
-                    // Since AdditionalProperties has undefined meaning, we treat it as potentially sensitive data
-                    if (EnableSensitiveData && response.AdditionalProperties is { } props)
+                    foreach (KeyValuePair<string, object?> prop in props)
                     {
-                        // Log all additional response properties as per-provider tags. This is non-normative, but it covers cases where
-                        // there's a per-provider specification in a best-effort manner (e.g. gen_ai.openai.response.system_fingerprint),
-                        // and more generally cases where there's additional useful information to be logged.
-                        foreach (KeyValuePair<string, object?> prop in props)
-                        {
-                            _ = activity.AddTag(
-                                OpenTelemetryConsts.GenAI.Response.PerProvider(_providerName, JsonNamingPolicy.SnakeCaseLower.ConvertName(prop.Key)),
-                                prop.Value);
-                        }
+                        _ = activity.AddTag(prop.Key, prop.Value);
                     }
                 }
             }
diff --git a/src/Libraries/Microsoft.Extensions.AI/Embeddings/OpenTelemetryEmbeddingGenerator.cs b/src/Libraries/Microsoft.Extensions.AI/Embeddings/OpenTelemetryEmbeddingGenerator.cs
index 6db30409b26..402222feaa7 100644
--- a/src/Libraries/Microsoft.Extensions.AI/Embeddings/OpenTelemetryEmbeddingGenerator.cs
+++ b/src/Libraries/Microsoft.Extensions.AI/Embeddings/OpenTelemetryEmbeddingGenerator.cs
@@ -6,7 +6,6 @@
 using System.Diagnostics;
 using System.Diagnostics.Metrics;
 using System.Linq;
-using System.Text.Json;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Extensions.Logging;
@@ -175,19 +174,13 @@ protected override void Dispose(bool disposing)
                     _ = activity.AddTag(OpenTelemetryConsts.GenAI.Request.EmbeddingDimensions, dimensionsValue);
                 }
 
-                // Log all additional request options as per-provider tags. This is non-normative, but it covers cases where
-                // there's a per-provider specification in a best-effort manner (e.g. gen_ai.openai.request.service_tier),
-                // and more generally cases where there's additional useful information to be logged.
+                // Log all additional request options as raw values on the span.
                 // Since AdditionalProperties has undefined meaning, we treat it as potentially sensitive data.
-                if (EnableSensitiveData &&
-                    _providerName is not null &&
-                    options?.AdditionalProperties is { } props)
+                if (EnableSensitiveData && options?.AdditionalProperties is { } props)
                 {
                     foreach (KeyValuePair<string, object?> prop in props)
                     {
-                        _ = activity.AddTag(
-                            OpenTelemetryConsts.GenAI.Request.PerProvider(_providerName, JsonNamingPolicy.SnakeCaseLower.ConvertName(prop.Key)),
-                            prop.Value);
+                        _ = activity.AddTag(prop.Key, prop.Value);
                     }
                 }
             }
@@ -255,18 +248,13 @@ private void TraceResponse(
                 _ = activity.AddTag(OpenTelemetryConsts.GenAI.Response.Model, responseModelId);
             }
 
-            // Log all additional response properties as per-provider tags. This is non-normative, but it covers cases where
-            // there's a per-provider specification in a best-effort manner (e.g. gen_ai.openai.response.system_fingerprint),
-            // and more generally cases where there's additional useful information to be logged.
-            if (EnableSensitiveData &&
-                _providerName is not null &&
-                embeddings?.AdditionalProperties is { } props)
+            // Log all additional response properties as raw values on the span.
+            // Since AdditionalProperties has undefined meaning, we treat it as potentially sensitive data.
+            if (EnableSensitiveData && embeddings?.AdditionalProperties is { } props)
             {
                 foreach (KeyValuePair<string, object?> prop in props)
                 {
-                    _ = activity.AddTag(
-                        OpenTelemetryConsts.GenAI.Response.PerProvider(_providerName, JsonNamingPolicy.SnakeCaseLower.ConvertName(prop.Key)),
-                        prop.Value);
+                    _ = activity.AddTag(prop.Key, prop.Value);
                 }
             }
         }
diff --git a/src/Libraries/Microsoft.Extensions.AI/OpenTelemetryConsts.cs b/src/Libraries/Microsoft.Extensions.AI/OpenTelemetryConsts.cs
index a1934faa526..faf7c32e4cb 100644
--- a/src/Libraries/Microsoft.Extensions.AI/OpenTelemetryConsts.cs
+++ b/src/Libraries/Microsoft.Extensions.AI/OpenTelemetryConsts.cs
@@ -90,8 +90,6 @@ public static class Request
             public const string Temperature = "gen_ai.request.temperature";
             public const string TopK = "gen_ai.request.top_k";
             public const string TopP = "gen_ai.request.top_p";
-
-            public static string PerProvider(string providerName, string parameterName) => $"{providerName}.request.{parameterName}";
         }
 
         public static class Response
@@ -99,8 +97,6 @@ public static class Response
             public const string FinishReasons = "gen_ai.response.finish_reasons";
             public const string Id = "gen_ai.response.id";
             public const string Model = "gen_ai.response.model";
-
-            public static string PerProvider(string providerName, string parameterName) => $"{providerName}.response.{parameterName}";
         }
 
         public static class Token
diff --git a/test/Libraries/Microsoft.Extensions.AI.Tests/ChatCompletion/OpenTelemetryChatClientTests.cs b/test/Libraries/Microsoft.Extensions.AI.Tests/ChatCompletion/OpenTelemetryChatClientTests.cs
index fcee53a68ee..4640b78f75d 100644
--- a/test/Libraries/Microsoft.Extensions.AI.Tests/ChatCompletion/OpenTelemetryChatClientTests.cs
+++ b/test/Libraries/Microsoft.Extensions.AI.Tests/ChatCompletion/OpenTelemetryChatClientTests.cs
@@ -163,16 +163,16 @@ async static IAsyncEnumerable<ChatResponseUpdate> CallbackAsync(
         Assert.Equal(7, activity.GetTagItem("gen_ai.request.top_k"));
         Assert.Equal(123, activity.GetTagItem("gen_ai.request.max_tokens"));
         Assert.Equal("""["hello", "world"]""", activity.GetTagItem("gen_ai.request.stop_sequences"));
-        Assert.Equal(enableSensitiveData ? "value1" : null, activity.GetTagItem("testservice.request.service_tier"));
-        Assert.Equal(enableSensitiveData ? "value2" : null, activity.GetTagItem("testservice.request.something_else"));
+        Assert.Equal(enableSensitiveData ? "value1" : null, activity.GetTagItem("service_tier"));
+        Assert.Equal(enableSensitiveData ? "value2" : null, activity.GetTagItem("SomethingElse"));
         Assert.Equal(42L, activity.GetTagItem("gen_ai.request.seed"));
 
         Assert.Equal("id123", activity.GetTagItem("gen_ai.response.id"));
         Assert.Equal("""["stop"]""", activity.GetTagItem("gen_ai.response.finish_reasons"));
         Assert.Equal(10, activity.GetTagItem("gen_ai.usage.input_tokens"));
         Assert.Equal(20, activity.GetTagItem("gen_ai.usage.output_tokens"));
-        Assert.Equal(enableSensitiveData ? "abcdefgh" : null, activity.GetTagItem("testservice.response.system_fingerprint"));
-        Assert.Equal(enableSensitiveData ? "value2" : null, activity.GetTagItem("testservice.response.and_something_else"));
+        Assert.Equal(enableSensitiveData ? "abcdefgh" : null, activity.GetTagItem("system_fingerprint"));
+        Assert.Equal(enableSensitiveData ? "value2" : null, activity.GetTagItem("AndSomethingElse"));
 
         Assert.True(activity.Duration.TotalMilliseconds > 0);
 
diff --git a/test/Libraries/Microsoft.Extensions.AI.Tests/Embeddings/OpenTelemetryEmbeddingGeneratorTests.cs b/test/Libraries/Microsoft.Extensions.AI.Tests/Embeddings/OpenTelemetryEmbeddingGeneratorTests.cs
index c3661f2c62b..c8419338e44 100644
--- a/test/Libraries/Microsoft.Extensions.AI.Tests/Embeddings/OpenTelemetryEmbeddingGeneratorTests.cs
+++ b/test/Libraries/Microsoft.Extensions.AI.Tests/Embeddings/OpenTelemetryEmbeddingGeneratorTests.cs
@@ -86,12 +86,12 @@ public async Task ExpectedInformationLogged_Async(string? perRequestModelId, boo
 
         Assert.Equal(expectedModelName, activity.GetTagItem("gen_ai.request.model"));
         Assert.Equal(1234, activity.GetTagItem("gen_ai.request.embedding.dimensions"));
-        Assert.Equal(enableSensitiveData ? "value1" : null, activity.GetTagItem("testservice.request.service_tier"));
-        Assert.Equal(enableSensitiveData ? "value2" : null, activity.GetTagItem("testservice.request.something_else"));
+        Assert.Equal(enableSensitiveData ? "value1" : null, activity.GetTagItem("service_tier"));
+        Assert.Equal(enableSensitiveData ? "value2" : null, activity.GetTagItem("SomethingElse"));
 
         Assert.Equal(10, activity.GetTagItem("gen_ai.usage.input_tokens"));
-        Assert.Equal(enableSensitiveData ? "abcdefgh" : null, activity.GetTagItem("testservice.response.system_fingerprint"));
-        Assert.Equal(enableSensitiveData ? "value3" : null, activity.GetTagItem("testservice.response.and_something_else"));
+        Assert.Equal(enableSensitiveData ? "abcdefgh" : null, activity.GetTagItem("system_fingerprint"));
+        Assert.Equal(enableSensitiveData ? "value3" : null, activity.GetTagItem("AndSomethingElse"));
 
         Assert.True(activity.Duration.TotalMilliseconds > 0);
     }

From 6911f8829c1f9a4c81dd393cecd41d2b2855ca2f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?David=20Cant=C3=BA?= <dacantu@microsoft.com>
Date: Mon, 8 Sep 2025 14:17:59 -0500
Subject: [PATCH 7/8] Add abstraction for remote MCP servers (#6664)

* Simpfliy Responses streaming handling

* Add abstraction for remote MCP servers

* Update MCP support to accomodate responses and approvals

---------

Co-authored-by: Stephen Toub <stoub@microsoft.com>
---
 .../ChatCompletion/RequiredChatToolMode.cs    |   6 -
 .../Contents/AIContent.cs                     |   4 +
 .../McpServerToolApprovalRequestContent.cs    |  41 ++
 .../McpServerToolApprovalResponseContent.cs   |  32 +
 .../Contents/McpServerToolCallContent.cs      |  55 ++
 .../Contents/McpServerToolResultContent.cs    |  41 ++
 ...dMcpServerToolAlwaysRequireApprovalMode.cs |  30 +
 .../HostedMcpServerToolApprovalMode.cs        |  48 ++
 ...edMcpServerToolNeverRequireApprovalMode.cs |  30 +
 ...cpServerToolRequireSpecificApprovalMode.cs |  66 ++
 ...icrosoft.Extensions.AI.Abstractions.csproj |   1 +
 .../{ => Tools}/AITool.cs                     |   0
 .../{ => Tools}/HostedCodeInterpreterTool.cs  |   0
 .../{ => Tools}/HostedFileSearchTool.cs       |   0
 .../Tools/HostedMcpServerTool.cs              |  89 +++
 .../{ => Tools}/HostedWebSearchTool.cs        |   0
 .../OpenAIJsonContext.cs                      |   1 +
 .../OpenAIResponsesChatClient.cs              | 216 ++++--
 ...tTests..cs => FunctionCallContentTests.cs} |   0
 .../Contents/McpServerToolCallContentTests.cs |  63 ++
 .../McpServerToolResultContentTests.cs        |  51 ++
 .../HostedMcpServerToolApprovalModeTests.cs   |  48 ++
 .../TestJsonSerializerContext.cs              |   1 +
 .../{ => Tools}/AIToolTests.cs                |   0
 .../HostedCodeInterpreterToolTests.cs         |   0
 .../{ => Tools}/HostedFileSearchToolTests.cs  |   0
 .../Tools/HostedMcpServerToolTests.cs         |  76 ++
 .../{ => Tools}/HostedWebSearchToolTests.cs   |   0
 .../OpenAIResponseClientIntegrationTests.cs   | 126 +++-
 .../OpenAIResponseClientTests.cs              | 677 ++++++++++++++++++
 30 files changed, 1650 insertions(+), 52 deletions(-)
 create mode 100644 src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/McpServerToolApprovalRequestContent.cs
 create mode 100644 src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/McpServerToolApprovalResponseContent.cs
 create mode 100644 src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/McpServerToolCallContent.cs
 create mode 100644 src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/McpServerToolResultContent.cs
 create mode 100644 src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedMcpServerToolAlwaysRequireApprovalMode.cs
 create mode 100644 src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedMcpServerToolApprovalMode.cs
 create mode 100644 src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedMcpServerToolNeverRequireApprovalMode.cs
 create mode 100644 src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedMcpServerToolRequireSpecificApprovalMode.cs
 rename src/Libraries/Microsoft.Extensions.AI.Abstractions/{ => Tools}/AITool.cs (100%)
 rename src/Libraries/Microsoft.Extensions.AI.Abstractions/{ => Tools}/HostedCodeInterpreterTool.cs (100%)
 rename src/Libraries/Microsoft.Extensions.AI.Abstractions/{ => Tools}/HostedFileSearchTool.cs (100%)
 create mode 100644 src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedMcpServerTool.cs
 rename src/Libraries/Microsoft.Extensions.AI.Abstractions/{ => Tools}/HostedWebSearchTool.cs (100%)
 rename test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/{FunctionCallContentTests..cs => FunctionCallContentTests.cs} (100%)
 create mode 100644 test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/McpServerToolCallContentTests.cs
 create mode 100644 test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/McpServerToolResultContentTests.cs
 create mode 100644 test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/HostedMcpServerToolApprovalModeTests.cs
 rename test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/{ => Tools}/AIToolTests.cs (100%)
 rename test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/{ => Tools}/HostedCodeInterpreterToolTests.cs (100%)
 rename test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/{ => Tools}/HostedFileSearchToolTests.cs (100%)
 create mode 100644 test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedMcpServerToolTests.cs
 rename test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/{ => Tools}/HostedWebSearchToolTests.cs (100%)

diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/ChatCompletion/RequiredChatToolMode.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/ChatCompletion/RequiredChatToolMode.cs
index 59ce51e7ef3..899ba04251e 100644
--- a/src/Libraries/Microsoft.Extensions.AI.Abstractions/ChatCompletion/RequiredChatToolMode.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/ChatCompletion/RequiredChatToolMode.cs
@@ -41,12 +41,6 @@ public RequiredChatToolMode(string? requiredFunctionName)
         RequiredFunctionName = requiredFunctionName;
     }
 
-    // The reason for not overriding Equals/GetHashCode (e.g., so two instances are equal if they
-    // have the same RequiredFunctionName) is to leave open the option to unseal the type in the
-    // future. If we did define equality based on RequiredFunctionName but a subclass added further
-    // fields, this would lead to wrong behavior unless the subclass author remembers to re-override
-    // Equals/GetHashCode as well, which they likely won't.
-
     /// <summary>Gets a string representing this instance to display in the debugger.</summary>
     [DebuggerBrowsable(DebuggerBrowsableState.Never)]
     private string DebuggerDisplay => $"Required: {RequiredFunctionName ?? "Any"}";
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/AIContent.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/AIContent.cs
index e3ee10ad50a..a0e240be991 100644
--- a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/AIContent.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/AIContent.cs
@@ -24,6 +24,10 @@ namespace Microsoft.Extensions.AI;
 // experimental types in its source generated files.
 // [JsonDerivedType(typeof(FunctionApprovalRequestContent), typeDiscriminator: "functionApprovalRequest")]
 // [JsonDerivedType(typeof(FunctionApprovalResponseContent), typeDiscriminator: "functionApprovalResponse")]
+// [JsonDerivedType(typeof(McpServerToolCallContent), typeDiscriminator: "mcpServerToolCall")]
+// [JsonDerivedType(typeof(McpServerToolResultContent), typeDiscriminator: "mcpServerToolResult")]
+// [JsonDerivedType(typeof(McpServerToolApprovalRequestContent), typeDiscriminator: "mcpServerToolApprovalRequest")]
+// [JsonDerivedType(typeof(McpServerToolApprovalResponseContent), typeDiscriminator: "mcpServerToolApprovalResponse")]
 
 public class AIContent
 {
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/McpServerToolApprovalRequestContent.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/McpServerToolApprovalRequestContent.cs
new file mode 100644
index 00000000000..8f302d901b4
--- /dev/null
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/McpServerToolApprovalRequestContent.cs
@@ -0,0 +1,41 @@
+// 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.Diagnostics.CodeAnalysis;
+using Microsoft.Shared.Diagnostics;
+
+namespace Microsoft.Extensions.AI;
+
+/// <summary>
+/// Represents a request for user approval of an MCP server tool call.
+/// </summary>
+[Experimental("MEAI001")]
+public sealed class McpServerToolApprovalRequestContent : UserInputRequestContent
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="McpServerToolApprovalRequestContent"/> class.
+    /// </summary>
+    /// <param name="id">The ID that uniquely identifies the MCP server tool approval request/response pair.</param>
+    /// <param name="toolCall">The tool call that requires user approval.</param>
+    /// <exception cref="ArgumentNullException"><paramref name="id"/> is <see langword="null"/>.</exception>
+    /// <exception cref="ArgumentException"><paramref name="id"/> is empty or composed entirely of whitespace.</exception>
+    /// <exception cref="ArgumentNullException"><paramref name="toolCall"/> is <see langword="null"/>.</exception>
+    public McpServerToolApprovalRequestContent(string id, McpServerToolCallContent toolCall)
+        : base(id)
+    {
+        ToolCall = Throw.IfNull(toolCall);
+    }
+
+    /// <summary>
+    /// Gets the tool call that pre-invoke approval is required for.
+    /// </summary>
+    public McpServerToolCallContent ToolCall { get; }
+
+    /// <summary>
+    /// Creates a <see cref="McpServerToolApprovalResponseContent"/> to indicate whether the function call is approved or rejected based on the value of <paramref name="approved"/>.
+    /// </summary>
+    /// <param name="approved"><see langword="true"/> if the function call is approved; otherwise, <see langword="false"/>.</param>
+    /// <returns>The <see cref="FunctionApprovalResponseContent"/> representing the approval response.</returns>
+    public McpServerToolApprovalResponseContent CreateResponse(bool approved) => new(Id, approved);
+}
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/McpServerToolApprovalResponseContent.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/McpServerToolApprovalResponseContent.cs
new file mode 100644
index 00000000000..0e239a79d7f
--- /dev/null
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/McpServerToolApprovalResponseContent.cs
@@ -0,0 +1,32 @@
+// 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.Diagnostics.CodeAnalysis;
+
+namespace Microsoft.Extensions.AI;
+
+/// <summary>
+/// Represents a response to an MCP server tool approval request.
+/// </summary>
+[Experimental("MEAI001")]
+public sealed class McpServerToolApprovalResponseContent : UserInputResponseContent
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="McpServerToolApprovalResponseContent"/> class.
+    /// </summary>
+    /// <param name="id">The ID that uniquely identifies the MCP server tool approval request/response pair.</param>
+    /// <param name="approved"><see langword="true"/> if the MCP server tool call is approved; otherwise, <see langword="false"/>.</param>
+    /// <exception cref="ArgumentNullException"><paramref name="id"/> is <see langword="null"/>.</exception>
+    /// <exception cref="ArgumentException"><paramref name="id"/> is empty or composed entirely of whitespace.</exception>
+    public McpServerToolApprovalResponseContent(string id, bool approved)
+        : base(id)
+    {
+        Approved = approved;
+    }
+
+    /// <summary>
+    /// Gets a value indicating whether the user approved the request.
+    /// </summary>
+    public bool Approved { get; }
+}
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/McpServerToolCallContent.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/McpServerToolCallContent.cs
new file mode 100644
index 00000000000..5ed6385789c
--- /dev/null
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/McpServerToolCallContent.cs
@@ -0,0 +1,55 @@
+// 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 System.Diagnostics.CodeAnalysis;
+using Microsoft.Shared.Diagnostics;
+
+namespace Microsoft.Extensions.AI;
+
+/// <summary>
+/// Represents a tool call request to a MCP server.
+/// </summary>
+/// <remarks>
+/// This content type is used to represent an invocation of an MCP server tool by a hosted service.
+/// It is informational only.
+/// </remarks>
+[Experimental("MEAI001")]
+public sealed class McpServerToolCallContent : AIContent
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="McpServerToolCallContent"/> class.
+    /// </summary>
+    /// <param name="callId">The tool call ID.</param>
+    /// <param name="toolName">The tool name.</param>
+    /// <param name="serverName">The MCP server name.</param>
+    /// <exception cref="ArgumentNullException"><paramref name="callId"/>, <paramref name="toolName"/>, or <paramref name="serverName"/> are <see langword="null"/>.</exception>
+    /// <exception cref="ArgumentException"><paramref name="callId"/>, <paramref name="toolName"/>, or <paramref name="serverName"/> are empty or composed entirely of whitespace.</exception>
+    public McpServerToolCallContent(string callId, string toolName, string serverName)
+    {
+        CallId = Throw.IfNullOrWhitespace(callId);
+        ToolName = Throw.IfNullOrWhitespace(toolName);
+        ServerName = Throw.IfNullOrWhitespace(serverName);
+    }
+
+    /// <summary>
+    /// Gets the tool call ID.
+    /// </summary>
+    public string CallId { get; }
+
+    /// <summary>
+    /// Gets the name of the tool called.
+    /// </summary>
+    public string ToolName { get; }
+
+    /// <summary>
+    /// Gets the name of the MCP server.
+    /// </summary>
+    public string ServerName { get; }
+
+    /// <summary>
+    /// Gets or sets the arguments used for the tool call.
+    /// </summary>
+    public IReadOnlyDictionary<string, object?>? Arguments { get; set; }
+}
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/McpServerToolResultContent.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/McpServerToolResultContent.cs
new file mode 100644
index 00000000000..b8329c74d99
--- /dev/null
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/McpServerToolResultContent.cs
@@ -0,0 +1,41 @@
+// 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 System.Diagnostics.CodeAnalysis;
+using Microsoft.Shared.Diagnostics;
+
+namespace Microsoft.Extensions.AI;
+
+/// <summary>
+/// Represents the result of a MCP server tool call.
+/// </summary>
+/// <remarks>
+/// This content type is used to represent the result of an invocation of an MCP server tool by a hosted service.
+/// It is informational only.
+/// </remarks>
+[Experimental("MEAI001")]
+public sealed class McpServerToolResultContent : AIContent
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="McpServerToolResultContent"/> class.
+    /// </summary>
+    /// <param name="callId">The tool call ID.</param>
+    /// <exception cref="ArgumentNullException"><paramref name="callId"/> is <see langword="null"/>.</exception>
+    /// <exception cref="ArgumentException"><paramref name="callId"/> is empty or composed entirely of whitespace.</exception>
+    public McpServerToolResultContent(string callId)
+    {
+        CallId = Throw.IfNullOrWhitespace(callId);
+    }
+
+    /// <summary>
+    /// Gets the tool call ID.
+    /// </summary>
+    public string CallId { get; }
+
+    /// <summary>
+    /// Gets or sets the output of the tool call.
+    /// </summary>
+    public IList<AIContent>? Output { get; set; }
+}
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedMcpServerToolAlwaysRequireApprovalMode.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedMcpServerToolAlwaysRequireApprovalMode.cs
new file mode 100644
index 00000000000..388ffbc2f7f
--- /dev/null
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedMcpServerToolAlwaysRequireApprovalMode.cs
@@ -0,0 +1,30 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+
+namespace Microsoft.Extensions.AI;
+
+/// <summary>
+/// Indicates that approval is always required for tool calls to a hosted MCP server.
+/// </summary>
+/// <remarks>
+/// Use <see cref="HostedMcpServerToolApprovalMode.AlwaysRequire"/> to get an instance of <see cref="HostedMcpServerToolAlwaysRequireApprovalMode"/>.
+/// </remarks>
+[Experimental("MEAI001")]
+[DebuggerDisplay(nameof(AlwaysRequire))]
+public sealed class HostedMcpServerToolAlwaysRequireApprovalMode : HostedMcpServerToolApprovalMode
+{
+    /// <summary>Initializes a new instance of the <see cref="HostedMcpServerToolAlwaysRequireApprovalMode"/> class.</summary>
+    /// <remarks>Use <see cref="HostedMcpServerToolApprovalMode.AlwaysRequire"/> to get an instance of <see cref="HostedMcpServerToolAlwaysRequireApprovalMode"/>.</remarks>
+    public HostedMcpServerToolAlwaysRequireApprovalMode()
+    {
+    }
+
+    /// <inheritdoc/>
+    public override bool Equals(object? obj) => obj is HostedMcpServerToolAlwaysRequireApprovalMode;
+
+    /// <inheritdoc/>
+    public override int GetHashCode() => typeof(HostedMcpServerToolAlwaysRequireApprovalMode).GetHashCode();
+}
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedMcpServerToolApprovalMode.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedMcpServerToolApprovalMode.cs
new file mode 100644
index 00000000000..47c3e3e48db
--- /dev/null
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedMcpServerToolApprovalMode.cs
@@ -0,0 +1,48 @@
+// 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;
+using System.Text.Json.Serialization;
+
+namespace Microsoft.Extensions.AI;
+
+/// <summary>
+/// Describes how approval is required for tool calls to a hosted MCP server.
+/// </summary>
+/// <remarks>
+/// The predefined values <see cref="AlwaysRequire" />, and <see cref="NeverRequire"/> are provided to specify handling for all tools.
+/// To specify approval behavior for individual tool names, use <see cref="RequireSpecific(IList{string}, IList{string})"/>.
+/// </remarks>
+[Experimental("MEAI001")]
+[JsonPolymorphic(TypeDiscriminatorPropertyName = "$type")]
+[JsonDerivedType(typeof(HostedMcpServerToolNeverRequireApprovalMode), typeDiscriminator: "never")]
+[JsonDerivedType(typeof(HostedMcpServerToolAlwaysRequireApprovalMode), typeDiscriminator: "always")]
+[JsonDerivedType(typeof(HostedMcpServerToolRequireSpecificApprovalMode), typeDiscriminator: "requireSpecific")]
+#pragma warning disable CA1052 // Static holder types should be Static or NotInheritable
+public class HostedMcpServerToolApprovalMode
+#pragma warning restore CA1052
+{
+    /// <summary>
+    /// Gets a predefined <see cref="HostedMcpServerToolApprovalMode"/> indicating that all tool calls to a hosted MCP server always require approval.
+    /// </summary>
+    public static HostedMcpServerToolAlwaysRequireApprovalMode AlwaysRequire { get; } = new();
+
+    /// <summary>
+    /// Gets a predefined <see cref="HostedMcpServerToolApprovalMode"/> indicating that all tool calls to a hosted MCP server never require approval.
+    /// </summary>
+    public static HostedMcpServerToolNeverRequireApprovalMode NeverRequire { get; } = new();
+
+    private protected HostedMcpServerToolApprovalMode()
+    {
+    }
+
+    /// <summary>
+    /// Instantiates a <see cref="HostedMcpServerToolApprovalMode"/> that specifies approval behavior for individual tool names.
+    /// </summary>
+    /// <param name="alwaysRequireApprovalToolNames">The list of tools names that always require approval.</param>
+    /// <param name="neverRequireApprovalToolNames">The list of tools names that never require approval.</param>
+    /// <returns>An instance of <see cref="HostedMcpServerToolRequireSpecificApprovalMode"/> for the specified tool names.</returns>
+    public static HostedMcpServerToolRequireSpecificApprovalMode RequireSpecific(IList<string>? alwaysRequireApprovalToolNames, IList<string>? neverRequireApprovalToolNames)
+        => new(alwaysRequireApprovalToolNames, neverRequireApprovalToolNames);
+}
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedMcpServerToolNeverRequireApprovalMode.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedMcpServerToolNeverRequireApprovalMode.cs
new file mode 100644
index 00000000000..bca80649f0d
--- /dev/null
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedMcpServerToolNeverRequireApprovalMode.cs
@@ -0,0 +1,30 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+
+namespace Microsoft.Extensions.AI;
+
+/// <summary>
+/// Indicates that approval is never required for tool calls to a hosted MCP server.
+/// </summary>
+/// <remarks>
+/// Use <see cref="HostedMcpServerToolApprovalMode.NeverRequire"/> to get an instance of <see cref="HostedMcpServerToolNeverRequireApprovalMode"/>.
+/// </remarks>
+[Experimental("MEAI001")]
+[DebuggerDisplay(nameof(NeverRequire))]
+public sealed class HostedMcpServerToolNeverRequireApprovalMode : HostedMcpServerToolApprovalMode
+{
+    /// <summary>Initializes a new instance of the <see cref="HostedMcpServerToolNeverRequireApprovalMode"/> class.</summary>
+    /// <remarks>Use <see cref="HostedMcpServerToolApprovalMode.NeverRequire"/> to get an instance of <see cref="HostedMcpServerToolNeverRequireApprovalMode"/>.</remarks>
+    public HostedMcpServerToolNeverRequireApprovalMode()
+    {
+    }
+
+    /// <inheritdoc/>
+    public override bool Equals(object? obj) => obj is HostedMcpServerToolNeverRequireApprovalMode;
+
+    /// <inheritdoc/>
+    public override int GetHashCode() => typeof(HostedMcpServerToolNeverRequireApprovalMode).GetHashCode();
+}
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedMcpServerToolRequireSpecificApprovalMode.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedMcpServerToolRequireSpecificApprovalMode.cs
new file mode 100644
index 00000000000..a5e870af7e7
--- /dev/null
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedMcpServerToolRequireSpecificApprovalMode.cs
@@ -0,0 +1,66 @@
+// 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 System.Diagnostics.CodeAnalysis;
+using System.Linq;
+
+namespace Microsoft.Extensions.AI;
+
+/// <summary>
+/// Represents a mode where approval behavior is specified for individual tool names.
+/// </summary>
+[Experimental("MEAI001")]
+public sealed class HostedMcpServerToolRequireSpecificApprovalMode : HostedMcpServerToolApprovalMode
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="HostedMcpServerToolRequireSpecificApprovalMode"/> class that specifies approval behavior for individual tool names.
+    /// </summary>
+    /// <param name="alwaysRequireApprovalToolNames">The list of tools names that always require approval.</param>
+    /// <param name="neverRequireApprovalToolNames">The list of tools names that never require approval.</param>
+    public HostedMcpServerToolRequireSpecificApprovalMode(IList<string>? alwaysRequireApprovalToolNames, IList<string>? neverRequireApprovalToolNames)
+    {
+        AlwaysRequireApprovalToolNames = alwaysRequireApprovalToolNames;
+        NeverRequireApprovalToolNames = neverRequireApprovalToolNames;
+    }
+
+    /// <summary>
+    /// Gets or sets the list of tool names that always require approval.
+    /// </summary>
+    public IList<string>? AlwaysRequireApprovalToolNames { get; set; }
+
+    /// <summary>
+    /// Gets or sets the list of tool names that never require approval.
+    /// </summary>
+    public IList<string>? NeverRequireApprovalToolNames { get; set; }
+
+    /// <inheritdoc/>
+    public override bool Equals(object? obj) => obj is HostedMcpServerToolRequireSpecificApprovalMode other &&
+        ListEquals(AlwaysRequireApprovalToolNames, other.AlwaysRequireApprovalToolNames) &&
+        ListEquals(NeverRequireApprovalToolNames, other.NeverRequireApprovalToolNames);
+
+    /// <inheritdoc/>
+    public override int GetHashCode() =>
+        HashCode.Combine(GetListHashCode(AlwaysRequireApprovalToolNames), GetListHashCode(NeverRequireApprovalToolNames));
+
+    private static bool ListEquals(IList<string>? list1, IList<string>? list2) =>
+        ReferenceEquals(list1, list2) ||
+        (list1 is not null && list2 is not null && list1.SequenceEqual(list2));
+
+    private static int GetListHashCode(IList<string>? list)
+    {
+        if (list is null)
+        {
+            return 0;
+        }
+
+        HashCode hc = default;
+        foreach (string item in list)
+        {
+            hc.Add(item);
+        }
+
+        return hc.ToHashCode();
+    }
+}
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Microsoft.Extensions.AI.Abstractions.csproj b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Microsoft.Extensions.AI.Abstractions.csproj
index f5472854def..25aa2f4c49d 100644
--- a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Microsoft.Extensions.AI.Abstractions.csproj
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Microsoft.Extensions.AI.Abstractions.csproj
@@ -32,6 +32,7 @@
 
   <ItemGroup Condition="'$(TargetFrameworkIdentifier)' != '.NETCoreApp'">
     <PackageReference Include="System.Text.Json" />
+    <PackageReference Include="Microsoft.Bcl.HashCode" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'net462'">
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/AITool.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/AITool.cs
similarity index 100%
rename from src/Libraries/Microsoft.Extensions.AI.Abstractions/AITool.cs
rename to src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/AITool.cs
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedCodeInterpreterTool.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedCodeInterpreterTool.cs
similarity index 100%
rename from src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedCodeInterpreterTool.cs
rename to src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedCodeInterpreterTool.cs
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedFileSearchTool.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedFileSearchTool.cs
similarity index 100%
rename from src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedFileSearchTool.cs
rename to src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedFileSearchTool.cs
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedMcpServerTool.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedMcpServerTool.cs
new file mode 100644
index 00000000000..54e760c78dd
--- /dev/null
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedMcpServerTool.cs
@@ -0,0 +1,89 @@
+// 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 System.Diagnostics.CodeAnalysis;
+using Microsoft.Shared.Diagnostics;
+
+namespace Microsoft.Extensions.AI;
+
+/// <summary>
+/// Represents a hosted MCP server tool that can be specified to an AI service.
+/// </summary>
+[Experimental("MEAI001")]
+public class HostedMcpServerTool : AITool
+{
+    /// <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="url">The URL of the remote MCP server.</param>
+    /// <exception cref="ArgumentNullException"><paramref name="serverName"/> or <paramref name="url"/> are <see langword="null"/>.</exception>
+    /// <exception cref="ArgumentException"><paramref name="serverName"/> is empty or composed entirely of whitespace.</exception>
+    public HostedMcpServerTool(string serverName, [StringSyntax(StringSyntaxAttribute.Uri)] string url)
+        : this(serverName, new Uri(Throw.IfNull(url)))
+    {
+    }
+
+    /// <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="url">The URL of the remote MCP server.</param>
+    /// <exception cref="ArgumentNullException"><paramref name="serverName"/> or <paramref name="url"/> are <see langword="null"/>.</exception>
+    /// <exception cref="ArgumentException"><paramref name="serverName"/> is empty or composed entirely of whitespace.</exception>
+    public HostedMcpServerTool(string serverName, Uri url)
+    {
+        ServerName = Throw.IfNullOrWhitespace(serverName);
+        Url = Throw.IfNull(url);
+    }
+
+    /// <summary>
+    /// Gets the name of the remote MCP server that is used to identify it.
+    /// </summary>
+    public string ServerName { get; }
+
+    /// <summary>
+    /// Gets the URL of the remote MCP server.
+    /// </summary>
+    public Uri Url { get; }
+
+    /// <summary>
+    /// Gets or sets the description of the remote MCP server, used to provide more context to the AI service.
+    /// </summary>
+    public string? ServerDescription { get; set; }
+
+    /// <summary>
+    /// Gets or sets the list of tools allowed to be used by the AI service.
+    /// </summary>
+    /// <remarks>
+    /// The default value is <see langword="null"/>, which allows any tool to be used.
+    /// </remarks>
+    public IList<string>? AllowedTools { get; set; }
+
+    /// <summary>
+    /// Gets or sets the approval mode that indicates when the AI service should require user approval for tool calls to the remote MCP server.
+    /// </summary>
+    /// <remarks>
+    /// <para>
+    /// You can set this property to <see cref="HostedMcpServerToolApprovalMode.AlwaysRequire"/> to require approval for all tool calls, 
+    /// or to <see cref="HostedMcpServerToolApprovalMode.NeverRequire"/> to never require approval.
+    /// </para>
+    /// <para>
+    /// The default value is <see langword="null"/>, which some providers may treat the same as <see cref="HostedMcpServerToolApprovalMode.AlwaysRequire"/>.
+    /// </para>
+    /// <para>
+    /// The underlying provider is not guaranteed to support or honor the approval mode.
+    /// </para>
+    /// </remarks>
+    public HostedMcpServerToolApprovalMode? ApprovalMode { get; set; }
+
+    /// <summary>
+    /// Gets or sets the HTTP headers that the AI service should use when calling the remote MCP server.
+    /// </summary>
+    /// <remarks>
+    /// This property is useful for specifying the authentication header or other headers required by the MCP server.
+    /// </remarks>
+    public IDictionary<string, string>? Headers { get; set; }
+}
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedWebSearchTool.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedWebSearchTool.cs
similarity index 100%
rename from src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedWebSearchTool.cs
rename to src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedWebSearchTool.cs
diff --git a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIJsonContext.cs b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIJsonContext.cs
index b4f75fe2c94..ab770568f69 100644
--- a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIJsonContext.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIJsonContext.cs
@@ -14,6 +14,7 @@ namespace Microsoft.Extensions.AI;
     WriteIndented = true)]
 [JsonSerializable(typeof(OpenAIClientExtensions.ToolJson))]
 [JsonSerializable(typeof(IDictionary<string, object?>))]
+[JsonSerializable(typeof(IReadOnlyDictionary<string, object?>))]
 [JsonSerializable(typeof(string[]))]
 [JsonSerializable(typeof(IEnumerable<string>))]
 [JsonSerializable(typeof(JsonElement))]
diff --git a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponsesChatClient.cs b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponsesChatClient.cs
index 0acfef52eb0..c025ae14d8a 100644
--- a/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponsesChatClient.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponsesChatClient.cs
@@ -159,6 +159,25 @@ internal static IEnumerable<ChatMessage> ToChatMessages(IEnumerable<ResponseItem
                     message.Contents.Add(fcc);
                     break;
 
+                case McpToolCallItem mtci:
+                    AddMcpToolCallContent(mtci, message.Contents);
+                    break;
+
+                case McpToolCallApprovalRequestItem mtcari:
+                    message.Contents.Add(new McpServerToolApprovalRequestContent(mtcari.Id, new(mtcari.Id, mtcari.ToolName, mtcari.ServerLabel)
+                    {
+                        Arguments = JsonSerializer.Deserialize(mtcari.ToolArguments.ToMemory().Span, OpenAIJsonContext.Default.IReadOnlyDictionaryStringObject)!,
+                        RawRepresentation = mtcari,
+                    })
+                    {
+                        RawRepresentation = mtcari,
+                    });
+                    break;
+
+                case McpToolCallApprovalResponseItem mtcari:
+                    message.Contents.Add(new McpServerToolApprovalResponseContent(mtcari.ApprovalRequestId, mtcari.Approved));
+                    break;
+
                 case FunctionCallOutputResponseItem functionCallOutputItem:
                     message.Contents.Add(new FunctionResultContent(functionCallOutputItem.CallId, functionCallOutputItem.FunctionOutput) { RawRepresentation = functionCallOutputItem });
                     break;
@@ -198,8 +217,7 @@ internal static async IAsyncEnumerable<ChatResponseUpdate> FromOpenAIStreamingRe
         string? modelId = null;
         string? lastMessageId = null;
         ChatRole? lastRole = null;
-        Dictionary<int, MessageResponseItem> outputIndexToMessages = [];
-        Dictionary<int, FunctionCallResponseItem>? functionCallItems = null;
+        bool anyFunctions = false;
 
         await foreach (var streamingUpdate in streamingResponseUpdates.WithCancellation(cancellationToken).ConfigureAwait(false))
         {
@@ -229,7 +247,7 @@ ChatResponseUpdate CreateUpdate(AIContent? content = null) =>
                     var update = CreateUpdate(ToUsageDetails(completedUpdate.Response) is { } usage ? new UsageContent(usage) : null);
                     update.FinishReason =
                         ToFinishReason(completedUpdate.Response?.IncompleteStatusDetails?.Reason) ??
-                        (functionCallItems is not null ? ChatFinishReason.ToolCalls :
+                        (anyFunctions ? ChatFinishReason.ToolCalls :
                         ChatFinishReason.Stop);
                     yield return update;
                     break;
@@ -239,65 +257,59 @@ ChatResponseUpdate CreateUpdate(AIContent? content = null) =>
                     switch (outputItemAddedUpdate.Item)
                     {
                         case MessageResponseItem mri:
-                            outputIndexToMessages[outputItemAddedUpdate.OutputIndex] = mri;
+                            lastMessageId = outputItemAddedUpdate.Item.Id;
+                            lastRole = ToChatRole(mri.Role);
                             break;
 
                         case FunctionCallResponseItem fcri:
-                            (functionCallItems ??= [])[outputItemAddedUpdate.OutputIndex] = fcri;
+                            anyFunctions = true;
+                            lastRole = ChatRole.Assistant;
                             break;
                     }
 
                     goto default;
 
-                case StreamingResponseOutputItemDoneUpdate outputItemDoneUpdate:
-                    _ = outputIndexToMessages.Remove(outputItemDoneUpdate.OutputIndex);
-
-                    if (outputItemDoneUpdate.Item is MessageResponseItem item &&
-                        item.Content is { Count: > 0 } content &&
-                        content.Any(c => c.OutputTextAnnotations is { Count: > 0 }))
-                    {
-                        AIContent annotatedContent = new();
-                        foreach (var c in content)
-                        {
-                            PopulateAnnotations(c, annotatedContent);
-                        }
-
-                        yield return CreateUpdate(annotatedContent);
-                        break;
-                    }
-
-                    goto default;
-
                 case StreamingResponseOutputTextDeltaUpdate outputTextDeltaUpdate:
-                {
-                    _ = outputIndexToMessages.TryGetValue(outputTextDeltaUpdate.OutputIndex, out MessageResponseItem? messageItem);
-                    lastMessageId = messageItem?.Id;
-                    lastRole = ToChatRole(messageItem?.Role);
-
                     yield return CreateUpdate(new TextContent(outputTextDeltaUpdate.Delta));
                     break;
-                }
 
-                case StreamingResponseFunctionCallArgumentsDoneUpdate functionCallOutputDoneUpdate:
-                {
-                    if (functionCallItems?.TryGetValue(functionCallOutputDoneUpdate.OutputIndex, out FunctionCallResponseItem? callInfo) is true)
-                    {
-                        _ = functionCallItems.Remove(functionCallOutputDoneUpdate.OutputIndex);
+                case StreamingResponseOutputItemDoneUpdate outputItemDoneUpdate when outputItemDoneUpdate.Item is FunctionCallResponseItem fcri:
+                    yield return CreateUpdate(OpenAIClientExtensions.ParseCallContent(fcri.FunctionArguments.ToString(), fcri.CallId, fcri.FunctionName));
+                    break;
 
-                        var fcc = OpenAIClientExtensions.ParseCallContent(
-                            functionCallOutputDoneUpdate.FunctionArguments.ToString(),
-                            callInfo.CallId,
-                            callInfo.FunctionName);
+                case StreamingResponseOutputItemDoneUpdate outputItemDoneUpdate when outputItemDoneUpdate.Item is McpToolCallItem mtci:
+                    var mcpUpdate = CreateUpdate();
+                    AddMcpToolCallContent(mtci, mcpUpdate.Contents);
+                    yield return mcpUpdate;
+                    break;
 
-                        lastMessageId = callInfo.Id;
-                        lastRole = ChatRole.Assistant;
+                case StreamingResponseOutputItemDoneUpdate outputItemDoneUpdate when outputItemDoneUpdate.Item is McpToolDefinitionListItem mtdli:
+                    yield return CreateUpdate(new AIContent { RawRepresentation = mtdli });
+                    break;
 
-                        yield return CreateUpdate(fcc);
-                        break;
+                case StreamingResponseOutputItemDoneUpdate outputItemDoneUpdate when outputItemDoneUpdate.Item is McpToolCallApprovalRequestItem mtcari:
+                    yield return CreateUpdate(new McpServerToolApprovalRequestContent(mtcari.Id, new(mtcari.Id, mtcari.ToolName, mtcari.ServerLabel)
+                    {
+                        Arguments = JsonSerializer.Deserialize(mtcari.ToolArguments.ToMemory().Span, OpenAIJsonContext.Default.IReadOnlyDictionaryStringObject)!,
+                        RawRepresentation = mtcari,
+                    })
+                    {
+                        RawRepresentation = mtcari,
+                    });
+                    break;
+
+                case StreamingResponseOutputItemDoneUpdate outputItemDoneUpdate when
+                        outputItemDoneUpdate.Item is MessageResponseItem mri &&
+                        mri.Content is { Count: > 0 } content &&
+                        content.Any(c => c.OutputTextAnnotations is { Count: > 0 }):
+                    AIContent annotatedContent = new();
+                    foreach (var c in content)
+                    {
+                        PopulateAnnotations(c, annotatedContent);
                     }
 
-                    goto default;
-                }
+                    yield return CreateUpdate(annotatedContent);
+                    break;
 
                 case StreamingResponseErrorUpdate errorUpdate:
                     yield return CreateUpdate(new ErrorContent(errorUpdate.Message)
@@ -440,6 +452,49 @@ private ResponseCreationOptions ToOpenAIResponseCreationOptions(ChatOptions? opt
 
                         result.Tools.Add(ModelReaderWriter.Read<ResponseTool>(BinaryData.FromString(json)));
                         break;
+
+                    case HostedMcpServerTool mcpTool:
+                        McpTool responsesMcpTool = ResponseTool.CreateMcpTool(
+                            mcpTool.ServerName,
+                            mcpTool.Url,
+                            mcpTool.Headers);
+
+                        if (mcpTool.AllowedTools is not null)
+                        {
+                            responsesMcpTool.AllowedTools = new();
+                            AddAllMcpFilters(mcpTool.AllowedTools, responsesMcpTool.AllowedTools);
+                        }
+
+                        switch (mcpTool.ApprovalMode)
+                        {
+                            case HostedMcpServerToolAlwaysRequireApprovalMode:
+                                responsesMcpTool.ToolCallApprovalPolicy = new McpToolCallApprovalPolicy(GlobalMcpToolCallApprovalPolicy.AlwaysRequireApproval);
+                                break;
+
+                            case HostedMcpServerToolNeverRequireApprovalMode:
+                                responsesMcpTool.ToolCallApprovalPolicy = new McpToolCallApprovalPolicy(GlobalMcpToolCallApprovalPolicy.NeverRequireApproval);
+                                break;
+
+                            case HostedMcpServerToolRequireSpecificApprovalMode specificMode:
+                                responsesMcpTool.ToolCallApprovalPolicy = new McpToolCallApprovalPolicy(new CustomMcpToolCallApprovalPolicy());
+
+                                if (specificMode.AlwaysRequireApprovalToolNames is { Count: > 0 } alwaysRequireToolNames)
+                                {
+                                    responsesMcpTool.ToolCallApprovalPolicy.CustomPolicy.ToolsAlwaysRequiringApproval = new();
+                                    AddAllMcpFilters(alwaysRequireToolNames, responsesMcpTool.ToolCallApprovalPolicy.CustomPolicy.ToolsAlwaysRequiringApproval);
+                                }
+
+                                if (specificMode.NeverRequireApprovalToolNames is { Count: > 0 } neverRequireToolNames)
+                                {
+                                    responsesMcpTool.ToolCallApprovalPolicy.CustomPolicy.ToolsNeverRequiringApproval = new();
+                                    AddAllMcpFilters(neverRequireToolNames, responsesMcpTool.ToolCallApprovalPolicy.CustomPolicy.ToolsNeverRequiringApproval);
+                                }
+
+                                break;
+                        }
+
+                        result.Tools.Add(responsesMcpTool);
+                        break;
                 }
             }
 
@@ -497,6 +552,8 @@ internal static IEnumerable<ResponseItem> ToOpenAIResponseItems(IEnumerable<Chat
     {
         _ = options; // currently unused
 
+        Dictionary<string, AIContent>? idToContentMapping = null;
+
         foreach (ChatMessage input in inputs)
         {
             if (input.Role == ChatRole.System ||
@@ -545,6 +602,10 @@ internal static IEnumerable<ResponseItem> ToOpenAIResponseItems(IEnumerable<Chat
 
                             yield return ResponseItem.CreateFunctionCallOutputItem(resultContent.CallId, result ?? string.Empty);
                             break;
+
+                        case McpServerToolApprovalResponseContent mcpApprovalResponseContent:
+                            yield return ResponseItem.CreateMcpApprovalResponseItem(mcpApprovalResponseContent.Id, mcpApprovalResponseContent.Approved);
+                            break;
                     }
                 }
 
@@ -577,6 +638,41 @@ internal static IEnumerable<ResponseItem> ToOpenAIResponseItems(IEnumerable<Chat
                                     callContent.Arguments,
                                     AIJsonUtilities.DefaultOptions.GetTypeInfo(typeof(IDictionary<string, object?>)))));
                             break;
+
+                        case McpServerToolApprovalRequestContent mcpApprovalRequestContent:
+                            // BUG https://github.com/openai/openai-dotnet/issues/664: Needs to be able to set an approvalRequestId
+                            yield return ResponseItem.CreateMcpApprovalRequestItem(
+                                mcpApprovalRequestContent.ToolCall.ServerName,
+                                mcpApprovalRequestContent.ToolCall.ToolName,
+                                BinaryData.FromBytes(JsonSerializer.SerializeToUtf8Bytes(mcpApprovalRequestContent.ToolCall.Arguments!, OpenAIJsonContext.Default.IReadOnlyDictionaryStringObject)));
+                            break;
+
+                        case McpServerToolCallContent mstcc:
+                            (idToContentMapping ??= [])[mstcc.CallId] = mstcc;
+                            break;
+
+                        case McpServerToolResultContent mstrc:
+                            if (idToContentMapping?.TryGetValue(mstrc.CallId, out AIContent? callContentFromMapping) is true &&
+                                callContentFromMapping is McpServerToolCallContent associatedCall)
+                            {
+                                _ = idToContentMapping.Remove(mstrc.CallId);
+                                McpToolCallItem mtci = ResponseItem.CreateMcpToolCallItem(
+                                    associatedCall.ServerName,
+                                    associatedCall.ToolName,
+                                    BinaryData.FromBytes(JsonSerializer.SerializeToUtf8Bytes(associatedCall.Arguments!, OpenAIJsonContext.Default.IReadOnlyDictionaryStringObject)));
+                                if (mstrc.Output?.OfType<ErrorContent>().FirstOrDefault() is ErrorContent errorContent)
+                                {
+                                    mtci.Error = BinaryData.FromString(errorContent.Message);
+                                }
+                                else
+                                {
+                                    mtci.ToolOutput = string.Concat(mstrc.Output?.OfType<TextContent>() ?? []);
+                                }
+
+                                yield return mtci;
+                            }
+
+                            break;
                     }
                 }
 
@@ -745,4 +841,34 @@ private static List<ResponseContentPart> ToResponseContentParts(IList<AIContent>
 
         return parts;
     }
+
+    /// <summary>Adds new <see cref="AIContent"/> for the specified <paramref name="mtci"/> into <paramref name="contents"/>.</summary>
+    private static void AddMcpToolCallContent(McpToolCallItem mtci, IList<AIContent> contents)
+    {
+        contents.Add(new McpServerToolCallContent(mtci.Id, mtci.ToolName, mtci.ServerLabel)
+        {
+            Arguments = JsonSerializer.Deserialize(mtci.ToolArguments.ToMemory().Span, OpenAIJsonContext.Default.IReadOnlyDictionaryStringObject)!,
+
+            // We purposefully do not set the RawRepresentation on the McpServerToolCallContent, only on the McpServerToolResultContent, to avoid
+            // the same McpToolCallItem being included on two different AIContent instances. When these are roundtripped, we want only one
+            // McpToolCallItem sent back for the pair.
+        });
+
+        contents.Add(new McpServerToolResultContent(mtci.Id)
+        {
+            RawRepresentation = mtci,
+            Output = [mtci.Error is not null ?
+                new ErrorContent(mtci.Error.ToString()) :
+                new TextContent(mtci.ToolOutput)],
+        });
+    }
+
+    /// <summary>Adds all of the tool names from <paramref name="toolNames"/> to <paramref name="filter"/>.</summary>
+    private static void AddAllMcpFilters(IList<string> toolNames, McpToolFilter filter)
+    {
+        foreach (var toolName in toolNames)
+        {
+            filter.ToolNames.Add(toolName);
+        }
+    }
 }
diff --git a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/FunctionCallContentTests..cs b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/FunctionCallContentTests.cs
similarity index 100%
rename from test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/FunctionCallContentTests..cs
rename to test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/FunctionCallContentTests.cs
diff --git a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/McpServerToolCallContentTests.cs b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/McpServerToolCallContentTests.cs
new file mode 100644
index 00000000000..ce6516124cd
--- /dev/null
+++ b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/McpServerToolCallContentTests.cs
@@ -0,0 +1,63 @@
+// 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 Xunit;
+
+namespace Microsoft.Extensions.AI;
+
+public class McpServerToolCallContentTests
+{
+    [Fact]
+    public void Constructor_PropsDefault()
+    {
+        McpServerToolCallContent c = new("callId1", "toolName", "serverName");
+
+        Assert.Null(c.RawRepresentation);
+        Assert.Null(c.AdditionalProperties);
+
+        Assert.Equal("callId1", c.CallId);
+        Assert.Equal("toolName", c.ToolName);
+        Assert.Equal("serverName", c.ServerName);
+
+        Assert.Null(c.Arguments);
+    }
+
+    [Fact]
+    public void Constructor_PropsRoundtrip()
+    {
+        McpServerToolCallContent c = new("callId1", "toolName", "serverName");
+
+        Assert.Null(c.RawRepresentation);
+        object raw = new();
+        c.RawRepresentation = raw;
+        Assert.Same(raw, c.RawRepresentation);
+
+        Assert.Null(c.AdditionalProperties);
+        AdditionalPropertiesDictionary props = new() { { "key", "value" } };
+        c.AdditionalProperties = props;
+        Assert.Same(props, c.AdditionalProperties);
+
+        Assert.Null(c.Arguments);
+        IReadOnlyDictionary<string, object?> args = new Dictionary<string, object?>();
+        c.Arguments = args;
+        Assert.Same(args, c.Arguments);
+
+        Assert.Equal("callId1", c.CallId);
+        Assert.Equal("toolName", c.ToolName);
+        Assert.Equal("serverName", c.ServerName);
+    }
+
+    [Fact]
+    public void Constructor_Throws()
+    {
+        Assert.Throws<ArgumentException>("callId", () => new McpServerToolCallContent(string.Empty, "name", "serverName"));
+        Assert.Throws<ArgumentException>("toolName", () => new McpServerToolCallContent("callId1", string.Empty, "serverName"));
+        Assert.Throws<ArgumentException>("serverName", () => new McpServerToolCallContent("callId1", "name", string.Empty));
+
+        Assert.Throws<ArgumentNullException>("callId", () => new McpServerToolCallContent(null!, "name", "serverName"));
+        Assert.Throws<ArgumentNullException>("toolName", () => new McpServerToolCallContent("callId1", null!, "serverName"));
+        Assert.Throws<ArgumentNullException>("serverName", () => new McpServerToolCallContent("callId1", "name", null!));
+    }
+}
diff --git a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/McpServerToolResultContentTests.cs b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/McpServerToolResultContentTests.cs
new file mode 100644
index 00000000000..ec20b37c9e2
--- /dev/null
+++ b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/McpServerToolResultContentTests.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;
+using System.Collections.Generic;
+using Xunit;
+
+namespace Microsoft.Extensions.AI;
+
+public class McpServerToolResultContentTests
+{
+    [Fact]
+    public void Constructor_PropsDefault()
+    {
+        McpServerToolResultContent c = new("callId");
+        Assert.Equal("callId", c.CallId);
+        Assert.Null(c.RawRepresentation);
+        Assert.Null(c.AdditionalProperties);
+        Assert.Null(c.Output);
+    }
+
+    [Fact]
+    public void Constructor_PropsRoundtrip()
+    {
+        McpServerToolResultContent c = new("callId");
+
+        Assert.Null(c.RawRepresentation);
+        object raw = new();
+        c.RawRepresentation = raw;
+        Assert.Same(raw, c.RawRepresentation);
+
+        Assert.Null(c.AdditionalProperties);
+        AdditionalPropertiesDictionary props = new() { { "key", "value" } };
+        c.AdditionalProperties = props;
+        Assert.Same(props, c.AdditionalProperties);
+
+        Assert.Equal("callId", c.CallId);
+
+        Assert.Null(c.Output);
+        IList<AIContent> output = [];
+        c.Output = output;
+        Assert.Same(output, c.Output);
+    }
+
+    [Fact]
+    public void Constructor_Throws()
+    {
+        Assert.Throws<ArgumentException>("callId", () => new McpServerToolResultContent(string.Empty));
+        Assert.Throws<ArgumentNullException>("callId", () => new McpServerToolResultContent(null!));
+    }
+}
diff --git a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/HostedMcpServerToolApprovalModeTests.cs b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/HostedMcpServerToolApprovalModeTests.cs
new file mode 100644
index 00000000000..3ad4690130a
--- /dev/null
+++ b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/HostedMcpServerToolApprovalModeTests.cs
@@ -0,0 +1,48 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Text.Json;
+using Xunit;
+
+namespace Microsoft.Extensions.AI;
+
+public class HostedMcpServerToolApprovalModeTests
+{
+    [Fact]
+    public void Singletons_Idempotent()
+    {
+        Assert.Same(HostedMcpServerToolApprovalMode.AlwaysRequire, HostedMcpServerToolApprovalMode.AlwaysRequire);
+        Assert.Same(HostedMcpServerToolApprovalMode.NeverRequire, HostedMcpServerToolApprovalMode.NeverRequire);
+    }
+
+    [Fact]
+    public void Serialization_NeverRequire_Roundtrips()
+    {
+        string json = JsonSerializer.Serialize(HostedMcpServerToolApprovalMode.NeverRequire, TestJsonSerializerContext.Default.HostedMcpServerToolApprovalMode);
+        Assert.Equal("""{"$type":"never"}""", json);
+
+        HostedMcpServerToolApprovalMode? result = JsonSerializer.Deserialize(json, TestJsonSerializerContext.Default.HostedMcpServerToolApprovalMode);
+        Assert.Equal(HostedMcpServerToolApprovalMode.NeverRequire, result);
+    }
+
+    [Fact]
+    public void Serialization_AlwaysRequire_Roundtrips()
+    {
+        string json = JsonSerializer.Serialize(HostedMcpServerToolApprovalMode.AlwaysRequire, TestJsonSerializerContext.Default.HostedMcpServerToolApprovalMode);
+        Assert.Equal("""{"$type":"always"}""", json);
+
+        HostedMcpServerToolApprovalMode? result = JsonSerializer.Deserialize(json, TestJsonSerializerContext.Default.HostedMcpServerToolApprovalMode);
+        Assert.Equal(HostedMcpServerToolApprovalMode.AlwaysRequire, result);
+    }
+
+    [Fact]
+    public void Serialization_RequireSpecific_Roundtrips()
+    {
+        var requireSpecific = HostedMcpServerToolApprovalMode.RequireSpecific(["ToolA", "ToolB"], ["ToolC"]);
+        string json = JsonSerializer.Serialize(requireSpecific, TestJsonSerializerContext.Default.HostedMcpServerToolApprovalMode);
+        Assert.Equal("""{"$type":"requireSpecific","alwaysRequireApprovalToolNames":["ToolA","ToolB"],"neverRequireApprovalToolNames":["ToolC"]}""", json);
+
+        HostedMcpServerToolApprovalMode? result = JsonSerializer.Deserialize(json, TestJsonSerializerContext.Default.HostedMcpServerToolApprovalMode);
+        Assert.Equal(requireSpecific, result);
+    }
+}
diff --git a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/TestJsonSerializerContext.cs b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/TestJsonSerializerContext.cs
index 609dac264eb..01de984d949 100644
--- a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/TestJsonSerializerContext.cs
+++ b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/TestJsonSerializerContext.cs
@@ -35,4 +35,5 @@ namespace Microsoft.Extensions.AI;
 [JsonSerializable(typeof(DayOfWeek[]))] // Used in Content tests
 [JsonSerializable(typeof(Guid))] // Used in Content tests
 [JsonSerializable(typeof(decimal))] // Used in Content tests
+[JsonSerializable(typeof(HostedMcpServerToolApprovalMode))]
 internal sealed partial class TestJsonSerializerContext : JsonSerializerContext;
diff --git a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/AIToolTests.cs b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/AIToolTests.cs
similarity index 100%
rename from test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/AIToolTests.cs
rename to test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/AIToolTests.cs
diff --git a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/HostedCodeInterpreterToolTests.cs b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedCodeInterpreterToolTests.cs
similarity index 100%
rename from test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/HostedCodeInterpreterToolTests.cs
rename to test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedCodeInterpreterToolTests.cs
diff --git a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/HostedFileSearchToolTests.cs b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedFileSearchToolTests.cs
similarity index 100%
rename from test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/HostedFileSearchToolTests.cs
rename to test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedFileSearchToolTests.cs
diff --git a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedMcpServerToolTests.cs b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedMcpServerToolTests.cs
new file mode 100644
index 00000000000..c77e59e3307
--- /dev/null
+++ b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedMcpServerToolTests.cs
@@ -0,0 +1,76 @@
+// 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 Xunit;
+
+namespace Microsoft.Extensions.AI;
+
+public class HostedMcpServerToolTests
+{
+    [Fact]
+    public void Constructor_PropsDefault()
+    {
+        HostedMcpServerTool tool = new("serverName", "https://localhost/");
+
+        Assert.Empty(tool.AdditionalProperties);
+
+        Assert.Equal("serverName", tool.ServerName);
+        Assert.Equal("https://localhost/", tool.Url.ToString());
+
+        Assert.Empty(tool.Description);
+        Assert.Null(tool.AllowedTools);
+        Assert.Null(tool.ApprovalMode);
+    }
+
+    [Fact]
+    public void Constructor_Roundtrips()
+    {
+        HostedMcpServerTool tool = new("serverName", "https://localhost/");
+
+        Assert.Empty(tool.AdditionalProperties);
+        Assert.Empty(tool.Description);
+        Assert.Equal(nameof(HostedMcpServerTool), tool.Name);
+
+        Assert.Equal("serverName", tool.ServerName);
+        Assert.Equal("https://localhost/", tool.Url.ToString());
+        Assert.Empty(tool.Description);
+
+        Assert.Null(tool.ServerDescription);
+        string serverDescription = "This is a test server";
+        tool.ServerDescription = serverDescription;
+        Assert.Equal(serverDescription, tool.ServerDescription);
+
+        Assert.Null(tool.AllowedTools);
+        List<string> allowedTools = ["tool1", "tool2"];
+        tool.AllowedTools = allowedTools;
+        Assert.Same(allowedTools, tool.AllowedTools);
+
+        Assert.Null(tool.ApprovalMode);
+        tool.ApprovalMode = HostedMcpServerToolApprovalMode.NeverRequire;
+        Assert.Same(HostedMcpServerToolApprovalMode.NeverRequire, tool.ApprovalMode);
+
+        tool.ApprovalMode = HostedMcpServerToolApprovalMode.AlwaysRequire;
+        Assert.Same(HostedMcpServerToolApprovalMode.AlwaysRequire, tool.ApprovalMode);
+
+        var customApprovalMode = new HostedMcpServerToolRequireSpecificApprovalMode(["tool1"], ["tool2"]);
+        tool.ApprovalMode = customApprovalMode;
+        Assert.Same(customApprovalMode, tool.ApprovalMode);
+
+        Assert.Null(tool.Headers);
+        Dictionary<string, string> headers = [];
+        tool.Headers = headers;
+        Assert.Same(headers, tool.Headers);
+    }
+
+    [Fact]
+    public void Constructor_Throws()
+    {
+        Assert.Throws<ArgumentException>(() => new HostedMcpServerTool(string.Empty, new Uri("https://localhost/")));
+        Assert.Throws<ArgumentNullException>(() => new HostedMcpServerTool(null!, new Uri("https://localhost/")));
+        Assert.Throws<ArgumentNullException>(() => new HostedMcpServerTool("name", (Uri)null!));
+        Assert.Throws<ArgumentNullException>(() => new HostedMcpServerTool("name", (string)null!));
+        Assert.Throws<UriFormatException>(() => new HostedMcpServerTool("name", string.Empty));
+    }
+}
diff --git a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/HostedWebSearchToolTests.cs b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedWebSearchToolTests.cs
similarity index 100%
rename from test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/HostedWebSearchToolTests.cs
rename to test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedWebSearchToolTests.cs
diff --git a/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIResponseClientIntegrationTests.cs b/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIResponseClientIntegrationTests.cs
index 007e86288f5..a46a06bb770 100644
--- a/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIResponseClientIntegrationTests.cs
+++ b/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIResponseClientIntegrationTests.cs
@@ -18,7 +18,7 @@ public class OpenAIResponseClientIntegrationTests : ChatClientIntegrationTests
 
     public override bool FunctionInvokingChatClientSetsConversationId => true;
 
-    // Test structure doesn't make sense with Respones.
+    // Test structure doesn't make sense with Responses.
     public override Task Caching_AfterFunctionInvocation_FunctionOutputUnchangedAsync() => Task.CompletedTask;
 
     [ConditionalFact]
@@ -49,4 +49,128 @@ public async Task UseWebSearch_AnnotationsReflectResults()
             Assert.NotEmpty(ca.Title);
         });
     }
+
+    [ConditionalFact]
+    public async Task RemoteMCP_ListTools()
+    {
+        SkipIfNotEnabled();
+
+        ChatOptions chatOptions = new()
+        {
+            Tools = [new HostedMcpServerTool("deepwiki", "https://mcp.deepwiki.com/mcp") { ApprovalMode = HostedMcpServerToolApprovalMode.NeverRequire }],
+        };
+
+        ChatResponse response = await CreateChatClient()!.GetResponseAsync("Which tools are available on the wiki_tools MCP server?", chatOptions);
+
+        Assert.Contains("read_wiki_structure", response.Text);
+        Assert.Contains("read_wiki_contents", response.Text);
+        Assert.Contains("ask_question", response.Text);
+    }
+
+    [ConditionalFact]
+    public async Task RemoteMCP_CallTool_ApprovalNeverRequired()
+    {
+        SkipIfNotEnabled();
+
+        await RunAsync(false, false);
+        await RunAsync(true, true);
+
+        async Task RunAsync(bool streaming, bool requireSpecific)
+        {
+            ChatOptions chatOptions = new()
+            {
+                Tools = [new HostedMcpServerTool("deepwiki", "https://mcp.deepwiki.com/mcp")
+                    {
+                        ApprovalMode = requireSpecific ?
+                            HostedMcpServerToolApprovalMode.RequireSpecific(null, ["read_wiki_structure", "ask_question"]) :
+                            HostedMcpServerToolApprovalMode.NeverRequire,
+                    }
+                ],
+            };
+
+            using var client = CreateChatClient()!;
+
+            const string Prompt = "Tell me the path to the README.md file for Microsoft.Extensions.AI.Abstractions in the dotnet/extensions repository";
+
+            ChatResponse response = streaming ?
+                await client.GetStreamingResponseAsync(Prompt, chatOptions).ToChatResponseAsync() :
+                await client.GetResponseAsync(Prompt, chatOptions);
+
+            Assert.NotNull(response);
+            Assert.NotEmpty(response.Messages.SelectMany(m => m.Contents).OfType<McpServerToolCallContent>());
+            Assert.NotEmpty(response.Messages.SelectMany(m => m.Contents).OfType<McpServerToolResultContent>());
+            Assert.Empty(response.Messages.SelectMany(m => m.Contents).OfType<McpServerToolApprovalRequestContent>());
+
+            Assert.Contains("src/Libraries/Microsoft.Extensions.AI.Abstractions/README.md", response.Text);
+        }
+    }
+
+    [ConditionalFact]
+    public async Task RemoteMCP_CallTool_ApprovalRequired()
+    {
+        SkipIfNotEnabled();
+
+        await RunAsync(false, false, false);
+        await RunAsync(true, true, false);
+        await RunAsync(false, false, true);
+        await RunAsync(true, true, true);
+
+        async Task RunAsync(bool streaming, bool requireSpecific, bool useConversationId)
+        {
+            ChatOptions chatOptions = new()
+            {
+                Tools = [new HostedMcpServerTool("deepwiki", "https://mcp.deepwiki.com/mcp")
+                    {
+                        ApprovalMode = requireSpecific ?
+                            HostedMcpServerToolApprovalMode.RequireSpecific(["read_wiki_structure", "ask_question"], null) :
+                            HostedMcpServerToolApprovalMode.AlwaysRequire,
+                    }
+                ],
+            };
+
+            using var client = CreateChatClient()!;
+
+            // Initial request
+            List<ChatMessage> input = [new ChatMessage(ChatRole.User, "Tell me the path to the README.md file for Microsoft.Extensions.AI.Abstractions in the dotnet/extensions repository")];
+            ChatResponse response = streaming ?
+                await client.GetStreamingResponseAsync(input, chatOptions).ToChatResponseAsync() :
+                await client.GetResponseAsync(input, chatOptions);
+
+            // Handle approvals of up to two rounds of tool calls
+            int approvalsCount = 0;
+            for (int i = 0; i < 2; i++)
+            {
+                if (useConversationId)
+                {
+                    chatOptions.ConversationId = response.ConversationId;
+                    input.Clear();
+                }
+                else
+                {
+                    input.AddRange(response.Messages);
+                }
+
+                var approvalResponse = new ChatMessage(ChatRole.Tool,
+                    response.Messages
+                            .SelectMany(m => m.Contents)
+                            .OfType<McpServerToolApprovalRequestContent>()
+                            .Select(c => new McpServerToolApprovalResponseContent(c.ToolCall.CallId, true))
+                            .ToArray());
+                if (approvalResponse.Contents.Count == 0)
+                {
+                    break;
+                }
+
+                approvalsCount += approvalResponse.Contents.Count;
+                input.Add(approvalResponse);
+                response = streaming ?
+                    await client.GetStreamingResponseAsync(input, chatOptions).ToChatResponseAsync() :
+                    await client.GetResponseAsync(input, chatOptions);
+            }
+
+            // Validate final response
+            Assert.Equal(2, approvalsCount);
+            Assert.Contains("src/Libraries/Microsoft.Extensions.AI.Abstractions/README.md", response.Text);
+        }
+    }
 }
diff --git a/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIResponseClientTests.cs b/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIResponseClientTests.cs
index 014fae0d39f..9175b6afd57 100644
--- a/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIResponseClientTests.cs
+++ b/test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIResponseClientTests.cs
@@ -8,6 +8,7 @@
 using System.ComponentModel;
 using System.Linq;
 using System.Net.Http;
+using System.Text.Json;
 using System.Threading.Tasks;
 using Microsoft.Extensions.Caching.Distributed;
 using Microsoft.Extensions.Caching.Memory;
@@ -824,6 +825,682 @@ public async Task MultipleOutputItems_NonStreaming()
         Assert.Equal(36, response.Usage.TotalTokenCount);
     }
 
+    [Fact]
+    public async Task McpToolCall_ApprovalNotRequired_NonStreaming()
+    {
+        const string Input = """
+            {
+                "model": "gpt-4o-mini",
+                "tools": [
+                    {
+                        "type": "mcp",
+                        "server_label": "deepwiki",
+                        "server_url": "https://mcp.deepwiki.com/mcp",
+                        "require_approval": "never"
+                    }
+                ],
+                "tool_choice": "auto",
+                "input": [
+                    {
+                        "type": "message",
+                        "role": "user",
+                        "content": [
+                            {
+                                "type": "input_text",
+                                "text": "Tell me the path to the README.md file for Microsoft.Extensions.AI.Abstractions in the dotnet/extensions repository"
+                            }
+                        ]
+                    }
+                ]
+            }
+            """;
+
+        const string Output = """
+            {
+                "id": "resp_68be416397ec81918c48ef286530b8140384f747588fc3f5",
+                "object": "response",
+                "created_at": 1757299043,
+                "status": "completed",
+                "background": false,
+                "error": null,
+                "incomplete_details": null,
+                "instructions": null,
+                "max_output_tokens": null,
+                "max_tool_calls": null,
+                "model": "gpt-4o-mini-2024-07-18",
+                "output": [
+                    {
+                        "id": "mcpl_68be4163aa80819185e792abdcde71670384f747588fc3f5",
+                        "type": "mcp_list_tools",
+                        "server_label": "deepwiki",
+                        "tools": [
+                            {
+                                "annotations": {
+                                    "read_only": false
+                                },
+                                "description": "Get a list of documentation topics for a GitHub repository",
+                                "input_schema": {
+                                    "type": "object",
+                                    "properties": {
+                                        "repoName": {
+                                            "type": "string",
+                                            "description": "GitHub repository: owner/repo (e.g. \"facebook/react\")"
+                                        }
+                                    },
+                                    "required": [
+                                        "repoName"
+                                    ],
+                                    "additionalProperties": false,
+                                    "$schema": "http://json-schema.org/draft-07/schema#"
+                                },
+                                "name": "read_wiki_structure"
+                            },
+                            {
+                                "annotations": {
+                                    "read_only": false
+                                },
+                                "description": "View documentation about a GitHub repository",
+                                "input_schema": {
+                                    "type": "object",
+                                    "properties": {
+                                        "repoName": {
+                                            "type": "string",
+                                            "description": "GitHub repository: owner/repo (e.g. \"facebook/react\")"
+                                        }
+                                    },
+                                    "required": [
+                                        "repoName"
+                                    ],
+                                    "additionalProperties": false,
+                                    "$schema": "http://json-schema.org/draft-07/schema#"
+                                },
+                                "name": "read_wiki_contents"
+                            },
+                            {
+                                "annotations": {
+                                    "read_only": false
+                                },
+                                "description": "Ask any question about a GitHub repository",
+                                "input_schema": {
+                                    "type": "object",
+                                    "properties": {
+                                        "repoName": {
+                                            "type": "string",
+                                            "description": "GitHub repository: owner/repo (e.g. \"facebook/react\")"
+                                        },
+                                        "question": {
+                                            "type": "string",
+                                            "description": "The question to ask about the repository"
+                                        }
+                                    },
+                                    "required": [
+                                        "repoName",
+                                        "question"
+                                    ],
+                                    "additionalProperties": false,
+                                    "$schema": "http://json-schema.org/draft-07/schema#"
+                                },
+                                "name": "ask_question"
+                            }
+                        ]
+                    },
+                    {
+                        "id": "mcp_68be4166acfc8191bc5e0a751eed358b0384f747588fc3f5",
+                        "type": "mcp_call",
+                        "approval_request_id": null,
+                        "arguments": "{\"repoName\":\"dotnet/extensions\"}",
+                        "error": null,
+                        "name": "read_wiki_structure",
+                        "output": "Available pages for dotnet/extensions:\n\n- 1 Overview\n- 2 Build System and CI/CD\n- 3 AI Extensions Framework\n  - 3.1 Core Abstractions\n  - 3.2 AI Function System\n  - 3.3 Chat Completion\n  - 3.4 Caching System\n  - 3.5 Evaluation and Reporting\n- 4 HTTP Resilience and Diagnostics\n  - 4.1 Standard Resilience\n  - 4.2 Hedging Strategies\n- 5 Telemetry and Compliance\n- 6 Testing Infrastructure\n  - 6.1 AI Service Integration Testing\n  - 6.2 Time Provider Testing",
+                        "server_label": "deepwiki"
+                    },
+                    {
+                        "id": "mcp_68be416900f88191837ae0718339a4ce0384f747588fc3f5",
+                        "type": "mcp_call",
+                        "approval_request_id": null,
+                        "arguments": "{\"repoName\":\"dotnet/extensions\",\"question\":\"What is the path to the README.md file for Microsoft.Extensions.AI.Abstractions?\"}",
+                        "error": null,
+                        "name": "ask_question",
+                        "output": "The `README.md` file for `Microsoft.Extensions.AI.Abstractions` is located at `src/Libraries/Microsoft.Extensions.AI.Abstractions/README.md` within the `dotnet/extensions` repository.  This file provides an overview of the `Microsoft.Extensions.AI.Abstractions` package, including installation instructions and usage examples for its core interfaces like `IChatClient` and `IEmbeddingGenerator`. \n\n## Path to README.md\n\nThe specific path to the `README.md` file for the `Microsoft.Extensions.AI.Abstractions` project is `src/Libraries/Microsoft.Extensions.AI.Abstractions/README.md`.  This path is also referenced in the `AI Extensions Framework` wiki page as a relevant source file. \n\n## Notes\n\nThe `Packaging.targets` file in the `eng/MSBuild` directory indicates that `README.md` files are included in packages when `IsPackable` and `IsShipping` properties are true.  This suggests that the `README.md` file located at `src/Libraries/Microsoft.Extensions.AI.Abstractions/README.md` is intended to be part of the distributed NuGet package for `Microsoft.Extensions.AI.Abstractions`. \n\nWiki pages you might want to explore:\n- [AI Extensions Framework (dotnet/extensions)](/wiki/dotnet/extensions#3)\n- [Chat Completion (dotnet/extensions)](/wiki/dotnet/extensions#3.3)\n\nView this search on DeepWiki: https://deepwiki.com/search/what-is-the-path-to-the-readme_315595bd-9b39-4f04-9fa3-42dc778fa9f3\n",
+                        "server_label": "deepwiki"
+                    },
+                    {
+                        "id": "msg_68be416fb43c819194a1d4ace2643a7e0384f747588fc3f5",
+                        "type": "message",
+                        "status": "completed",
+                        "content": [
+                            {
+                                "type": "output_text",
+                                "annotations": [],
+                                "logprobs": [],
+                                "text": "The `README.md` file for `Microsoft.Extensions.AI.Abstractions` is located at:\n\n```\nsrc/Libraries/Microsoft.Extensions.AI.Abstractions/README.md\n```\n\nThis file includes an overview, installation instructions, and usage examples related to the package."
+                            }
+                        ],
+                        "role": "assistant"
+                    }
+                ],
+                "parallel_tool_calls": true,
+                "previous_response_id": null,
+                "prompt_cache_key": null,
+                "reasoning": {
+                    "effort": null,
+                    "summary": null
+                },
+                "safety_identifier": null,
+                "service_tier": "default",
+                "store": true,
+                "temperature": 1,
+                "text": {
+                    "format": {
+                        "type": "text"
+                    },
+                    "verbosity": "medium"
+                },
+                "tool_choice": "auto",
+                "tools": [
+                    {
+                        "type": "mcp",
+                        "allowed_tools": null,
+                        "headers": null,
+                        "require_approval": "never",
+                        "server_description": null,
+                        "server_label": "deepwiki",
+                        "server_url": "https://mcp.deepwiki.com/<redacted>"
+                    }
+                ],
+                "top_logprobs": 0,
+                "top_p": 1,
+                "truncation": "disabled",
+                "usage": {
+                    "input_tokens": 1329,
+                    "input_tokens_details": {
+                        "cached_tokens": 0
+                    },
+                    "output_tokens": 123,
+                    "output_tokens_details": {
+                        "reasoning_tokens": 0
+                    },
+                    "total_tokens": 1452
+                },
+                "user": null,
+                "metadata": {}
+            }
+            """;
+
+        using VerbatimHttpHandler handler = new(Input, Output);
+        using HttpClient httpClient = new(handler);
+        using IChatClient client = CreateResponseClient(httpClient, "gpt-4o-mini");
+
+        ChatOptions chatOptions = new()
+        {
+            Tools = [new HostedMcpServerTool("deepwiki", "https://mcp.deepwiki.com/mcp")
+                {
+                    ApprovalMode = HostedMcpServerToolApprovalMode.NeverRequire,
+                }
+            ],
+        };
+
+        var response = await client.GetResponseAsync("Tell me the path to the README.md file for Microsoft.Extensions.AI.Abstractions in the dotnet/extensions repository", chatOptions);
+        Assert.NotNull(response);
+
+        Assert.Equal("resp_68be416397ec81918c48ef286530b8140384f747588fc3f5", response.ResponseId);
+        Assert.Equal("resp_68be416397ec81918c48ef286530b8140384f747588fc3f5", response.ConversationId);
+        Assert.Equal("gpt-4o-mini-2024-07-18", response.ModelId);
+        Assert.Equal(DateTimeOffset.FromUnixTimeSeconds(1_757_299_043), response.CreatedAt);
+        Assert.Null(response.FinishReason);
+
+        var message = Assert.Single(response.Messages);
+        Assert.Equal(ChatRole.Assistant, response.Messages[0].Role);
+        Assert.Equal("The `README.md` file for `Microsoft.Extensions.AI.Abstractions` is located at:\n\n```\nsrc/Libraries/Microsoft.Extensions.AI.Abstractions/README.md\n```\n\nThis file includes an overview, installation instructions, and usage examples related to the package.", response.Messages[0].Text);
+
+        Assert.Equal(6, message.Contents.Count);
+
+        var firstCall = Assert.IsType<McpServerToolCallContent>(message.Contents[1]);
+        Assert.Equal("mcp_68be4166acfc8191bc5e0a751eed358b0384f747588fc3f5", firstCall.CallId);
+        Assert.Equal("deepwiki", firstCall.ServerName);
+        Assert.Equal("read_wiki_structure", firstCall.ToolName);
+        Assert.NotNull(firstCall.Arguments);
+        Assert.Single(firstCall.Arguments);
+        Assert.Equal("dotnet/extensions", ((JsonElement)firstCall.Arguments["repoName"]!).GetString());
+
+        var firstResult = Assert.IsType<McpServerToolResultContent>(message.Contents[2]);
+        Assert.Equal("mcp_68be4166acfc8191bc5e0a751eed358b0384f747588fc3f5", firstResult.CallId);
+        Assert.NotNull(firstResult.Output);
+        Assert.StartsWith("Available pages for dotnet/extensions", Assert.IsType<TextContent>(Assert.Single(firstResult.Output)).Text);
+
+        var secondCall = Assert.IsType<McpServerToolCallContent>(message.Contents[3]);
+        Assert.Equal("mcp_68be416900f88191837ae0718339a4ce0384f747588fc3f5", secondCall.CallId);
+        Assert.Equal("deepwiki", secondCall.ServerName);
+        Assert.Equal("ask_question", secondCall.ToolName);
+        Assert.NotNull(secondCall.Arguments);
+        Assert.Equal("dotnet/extensions", ((JsonElement)secondCall.Arguments["repoName"]!).GetString());
+        Assert.Equal("What is the path to the README.md file for Microsoft.Extensions.AI.Abstractions?", ((JsonElement)secondCall.Arguments["question"]!).GetString());
+
+        var secondResult = Assert.IsType<McpServerToolResultContent>(message.Contents[4]);
+        Assert.Equal("mcp_68be416900f88191837ae0718339a4ce0384f747588fc3f5", secondResult.CallId);
+        Assert.NotNull(secondResult.Output);
+        Assert.StartsWith("The `README.md` file for `Microsoft.Extensions.AI.Abstractions` is located at", Assert.IsType<TextContent>(Assert.Single(secondResult.Output)).Text);
+
+        Assert.NotNull(response.Usage);
+        Assert.Equal(1329, response.Usage.InputTokenCount);
+        Assert.Equal(123, response.Usage.OutputTokenCount);
+        Assert.Equal(1452, response.Usage.TotalTokenCount);
+    }
+
+    [Fact]
+    public async Task McpToolCall_ApprovalNotRequired_Streaming()
+    {
+        const string Input = """
+            {
+                "model": "gpt-4o-mini",
+                "tools": [
+                    {
+                        "type": "mcp",
+                        "server_label": "deepwiki",
+                        "server_url": "https://mcp.deepwiki.com/mcp",
+                        "require_approval": "never"
+                    }
+                ],
+                "tool_choice": "auto",
+                "input": [
+                    {
+                        "type": "message",
+                        "role": "user",
+                        "content": [
+                            {
+                                "type": "input_text",
+                                "text": "Tell me the path to the README.md file for Microsoft.Extensions.AI.Abstractions in the dotnet/extensions repository"
+                            }
+                        ]
+                    }
+                ],
+                "stream": true
+            }
+            """;
+
+        const string Output = """
+            event: response.created
+            data: {"type":"response.created","sequence_number":0,"response":{"id":"resp_68be44fd7298819e82fd82c8516e970d03a2537be0e84a54","object":"response","created_at":1757299965,"status":"in_progress","background":false,"error":null,"incomplete_details":null,"instructions":null,"max_output_tokens":null,"max_tool_calls":null,"model":"gpt-4o-mini-2024-07-18","output":[],"parallel_tool_calls":true,"previous_response_id":null,"prompt_cache_key":null,"reasoning":{"effort":null,"summary":null},"safety_identifier":null,"service_tier":"auto","store":true,"temperature":1.0,"text":{"format":{"type":"text"},"verbosity":"medium"},"tool_choice":"auto","tools":[{"type":"mcp","allowed_tools":null,"headers":null,"require_approval":"never","server_description":null,"server_label":"deepwiki","server_url":"https://mcp.deepwiki.com/<redacted>"}],"top_logprobs":0,"top_p":1.0,"truncation":"disabled","usage":null,"user":null,"metadata":{}}}
+
+            event: response.in_progress
+            data: {"type":"response.in_progress","sequence_number":1,"response":{"id":"resp_68be44fd7298819e82fd82c8516e970d03a2537be0e84a54","object":"response","created_at":1757299965,"status":"in_progress","background":false,"error":null,"incomplete_details":null,"instructions":null,"max_output_tokens":null,"max_tool_calls":null,"model":"gpt-4o-mini-2024-07-18","output":[],"parallel_tool_calls":true,"previous_response_id":null,"prompt_cache_key":null,"reasoning":{"effort":null,"summary":null},"safety_identifier":null,"service_tier":"auto","store":true,"temperature":1.0,"text":{"format":{"type":"text"},"verbosity":"medium"},"tool_choice":"auto","tools":[{"type":"mcp","allowed_tools":null,"headers":null,"require_approval":"never","server_description":null,"server_label":"deepwiki","server_url":"https://mcp.deepwiki.com/<redacted>"}],"top_logprobs":0,"top_p":1.0,"truncation":"disabled","usage":null,"user":null,"metadata":{}}}
+
+            event: response.output_item.added
+            data: {"type":"response.output_item.added","sequence_number":2,"output_index":0,"item":{"id":"mcpl_68be44fd8f68819eba7a74a2f6d27a5a03a2537be0e84a54","type":"mcp_list_tools","server_label":"deepwiki","tools":[]}}
+
+            event: response.mcp_list_tools.in_progress
+            data: {"type":"response.mcp_list_tools.in_progress","sequence_number":3,"output_index":0,"item_id":"mcpl_68be44fd8f68819eba7a74a2f6d27a5a03a2537be0e84a54"}
+
+            event: response.mcp_list_tools.completed
+            data: {"type":"response.mcp_list_tools.completed","sequence_number":4,"output_index":0,"item_id":"mcpl_68be44fd8f68819eba7a74a2f6d27a5a03a2537be0e84a54"}
+
+            event: response.output_item.done
+            data: {"type":"response.output_item.done","sequence_number":5,"output_index":0,"item":{"id":"mcpl_68be44fd8f68819eba7a74a2f6d27a5a03a2537be0e84a54","type":"mcp_list_tools","server_label":"deepwiki","tools":[{"annotations":{"read_only":false},"description":"Get a list of documentation topics for a GitHub repository","input_schema":{"type":"object","properties":{"repoName":{"type":"string","description":"GitHub repository: owner/repo (e.g. \"facebook/react\")"}},"required":["repoName"],"additionalProperties":false,"$schema":"http://json-schema.org/draft-07/schema#"},"name":"read_wiki_structure"},{"annotations":{"read_only":false},"description":"View documentation about a GitHub repository","input_schema":{"type":"object","properties":{"repoName":{"type":"string","description":"GitHub repository: owner/repo (e.g. \"facebook/react\")"}},"required":["repoName"],"additionalProperties":false,"$schema":"http://json-schema.org/draft-07/schema#"},"name":"read_wiki_contents"},{"annotations":{"read_only":false},"description":"Ask any question about a GitHub repository","input_schema":{"type":"object","properties":{"repoName":{"type":"string","description":"GitHub repository: owner/repo (e.g. \"facebook/react\")"},"question":{"type":"string","description":"The question to ask about the repository"}},"required":["repoName","question"],"additionalProperties":false,"$schema":"http://json-schema.org/draft-07/schema#"},"name":"ask_question"}]}}
+
+            event: response.output_item.added
+            data: {"type":"response.output_item.added","sequence_number":6,"output_index":1,"item":{"id":"mcp_68be4503d45c819e89cb574361c8eba003a2537be0e84a54","type":"mcp_call","approval_request_id":null,"arguments":"","error":null,"name":"read_wiki_structure","output":null,"server_label":"deepwiki"}}
+
+            event: response.mcp_call.in_progress
+            data: {"type":"response.mcp_call.in_progress","sequence_number":7,"output_index":1,"item_id":"mcp_68be4503d45c819e89cb574361c8eba003a2537be0e84a54"}
+
+            event: response.mcp_call_arguments.delta
+            data: {"type":"response.mcp_call_arguments.delta","sequence_number":8,"output_index":1,"item_id":"mcp_68be4503d45c819e89cb574361c8eba003a2537be0e84a54","delta":"{\"repoName\":\"dotnet/extensions\"}","obfuscation":""}
+
+            event: response.mcp_call_arguments.done
+            data: {"type":"response.mcp_call_arguments.done","sequence_number":9,"output_index":1,"item_id":"mcp_68be4503d45c819e89cb574361c8eba003a2537be0e84a54","arguments":"{\"repoName\":\"dotnet/extensions\"}"}
+
+            event: response.mcp_call.completed
+            data: {"type":"response.mcp_call.completed","sequence_number":10,"output_index":1,"item_id":"mcp_68be4503d45c819e89cb574361c8eba003a2537be0e84a54"}
+
+            event: response.output_item.done
+            data: {"type":"response.output_item.done","sequence_number":11,"output_index":1,"item":{"id":"mcp_68be4503d45c819e89cb574361c8eba003a2537be0e84a54","type":"mcp_call","approval_request_id":null,"arguments":"{\"repoName\":\"dotnet/extensions\"}","error":null,"name":"read_wiki_structure","output":"Available pages for dotnet/extensions:\n\n- 1 Overview\n- 2 Build System and CI/CD\n- 3 AI Extensions Framework\n  - 3.1 Core Abstractions\n  - 3.2 AI Function System\n  - 3.3 Chat Completion\n  - 3.4 Caching System\n  - 3.5 Evaluation and Reporting\n- 4 HTTP Resilience and Diagnostics\n  - 4.1 Standard Resilience\n  - 4.2 Hedging Strategies\n- 5 Telemetry and Compliance\n- 6 Testing Infrastructure\n  - 6.1 AI Service Integration Testing\n  - 6.2 Time Provider Testing","server_label":"deepwiki"}}
+
+            event: response.output_item.added
+            data: {"type":"response.output_item.added","sequence_number":12,"output_index":2,"item":{"id":"mcp_68be4505f134819e806c002f27cce0c303a2537be0e84a54","type":"mcp_call","approval_request_id":null,"arguments":"","error":null,"name":"ask_question","output":null,"server_label":"deepwiki"}}
+
+            event: response.mcp_call.in_progress
+            data: {"type":"response.mcp_call.in_progress","sequence_number":13,"output_index":2,"item_id":"mcp_68be4505f134819e806c002f27cce0c303a2537be0e84a54"}
+
+            event: response.mcp_call_arguments.delta
+            data: {"type":"response.mcp_call_arguments.delta","sequence_number":14,"output_index":2,"item_id":"mcp_68be4505f134819e806c002f27cce0c303a2537be0e84a54","delta":"{\"repoName\":\"dotnet/extensions\",\"question\":\"What is the path to the README.md file for Microsoft.Extensions.AI.Abstractions?\"}","obfuscation":"IT"}
+
+            event: response.mcp_call_arguments.done
+            data: {"type":"response.mcp_call_arguments.done","sequence_number":15,"output_index":2,"item_id":"mcp_68be4505f134819e806c002f27cce0c303a2537be0e84a54","arguments":"{\"repoName\":\"dotnet/extensions\",\"question\":\"What is the path to the README.md file for Microsoft.Extensions.AI.Abstractions?\"}"}
+
+            event: response.mcp_call.completed
+            data: {"type":"response.mcp_call.completed","sequence_number":16,"output_index":2,"item_id":"mcp_68be4505f134819e806c002f27cce0c303a2537be0e84a54"}
+
+            event: response.output_item.done
+            data: {"type":"response.output_item.done","sequence_number":17,"output_index":2,"item":{"id":"mcp_68be4505f134819e806c002f27cce0c303a2537be0e84a54","type":"mcp_call","approval_request_id":null,"arguments":"{\"repoName\":\"dotnet/extensions\",\"question\":\"What is the path to the README.md file for Microsoft.Extensions.AI.Abstractions?\"}","error":null,"name":"ask_question","output":"The path to the `README.md` file for `Microsoft.Extensions.AI.Abstractions` is `src/Libraries/Microsoft.Extensions.AI.Abstractions/README.md` . This file provides an overview of the `Microsoft.Extensions.AI.Abstractions` library, including installation instructions and usage examples for its core components like `IChatClient` and `IEmbeddingGenerator`   .\n\n## README.md Content Overview\nThe `README.md` file for `Microsoft.Extensions.AI.Abstractions` details the purpose of the library, which is to provide abstractions for generative AI components . It includes instructions on how to install the NuGet package `Microsoft.Extensions.AI.Abstractions` .\n\nThe document also provides usage examples for the `IChatClient` interface, which defines methods for interacting with AI services that offer \"chat\" capabilities . This includes examples for requesting both complete and streaming chat responses  .\n\nFurthermore, the `README.md` explains the `IEmbeddingGenerator` interface, which is used for generating vector embeddings from input values . It demonstrates how to use `GenerateAsync` to create embeddings . The file also discusses how both `IChatClient` and `IEmbeddingGenerator` implementations can be layered to create pipelines of functionality, incorporating features like caching and telemetry  .\n\nNotes:\nThe user's query specifically asked for the path to the `README.md` file for `Microsoft.Extensions.AI.Abstractions`. The provided codebase context, particularly the wiki page for \"AI Extensions Framework\", directly lists this file as a relevant source file . The content of the `README.md` file itself further confirms its relevance to the `Microsoft.Extensions.AI.Abstractions` library.\n\nWiki pages you might want to explore:\n- [AI Extensions Framework (dotnet/extensions)](/wiki/dotnet/extensions#3)\n- [Chat Completion (dotnet/extensions)](/wiki/dotnet/extensions#3.3)\n\nView this search on DeepWiki: https://deepwiki.com/search/what-is-the-path-to-the-readme_bb6bee43-3136-4b21-bc5d-02ca1611d857\n","server_label":"deepwiki"}}
+
+            event: response.output_item.added
+            data: {"type":"response.output_item.added","sequence_number":18,"output_index":3,"item":{"id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","type":"message","status":"in_progress","content":[],"role":"assistant"}}
+
+            event: response.content_part.added
+            data: {"type":"response.content_part.added","sequence_number":19,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"part":{"type":"output_text","annotations":[],"logprobs":[],"text":""}}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":20,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"The","logprobs":[],"obfuscation":"a5sNdjeWpJXIK"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":21,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" path","logprobs":[],"obfuscation":"2oWbALsHrtv"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":22,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" to","logprobs":[],"obfuscation":"K8lRBCaiusvjP"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":23,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" the","logprobs":[],"obfuscation":"LP7Xp4jDWA5w"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":24,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" `","logprobs":[],"obfuscation":"2rUNEj0h3wLlee"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":25,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"README","logprobs":[],"obfuscation":"PSbOrCj8y6"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":26,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":".md","logprobs":[],"obfuscation":"Do0BCY4kJ6wQW"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":27,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"`","logprobs":[],"obfuscation":"3fTPkjHu1Oq83DT"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":28,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" file","logprobs":[],"obfuscation":"CI9PXx3sH06"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":29,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" for","logprobs":[],"obfuscation":"fJuaoSPsMge8"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":30,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" `","logprobs":[],"obfuscation":"O1h4Q0T72OM4e7"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":31,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"Microsoft","logprobs":[],"obfuscation":"E2YPgfE"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":32,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":".Extensions","logprobs":[],"obfuscation":"vfVX8"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":33,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":".A","logprobs":[],"obfuscation":"EwDmSMHqymBRl1"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":34,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"I","logprobs":[],"obfuscation":"QQfjze1z7QhvcJE"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":35,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":".A","logprobs":[],"obfuscation":"7fLbFXKbxOMkBi"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":36,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"bst","logprobs":[],"obfuscation":"3p1svK7Jd1N7C"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":37,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"ractions","logprobs":[],"obfuscation":"Cl2xCwTC"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":38,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"`","logprobs":[],"obfuscation":"ObDOKE72QOlXSx9"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":39,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" in","logprobs":[],"obfuscation":"FJwPbDYgh4XjL"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":40,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" the","logprobs":[],"obfuscation":"e8cV5qt7hEsz"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":41,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" `","logprobs":[],"obfuscation":"Hf8ZQDFLfImh3e"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":42,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"dot","logprobs":[],"obfuscation":"0lh2vLiYye2JI"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":43,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"net","logprobs":[],"obfuscation":"g5fzb2qtk4Piz"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":44,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"/extensions","logprobs":[],"obfuscation":"egpos"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":45,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"`","logprobs":[],"obfuscation":"gXw3bKveEVIKXux"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":46,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" repository","logprobs":[],"obfuscation":"rqhlC"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":47,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" is","logprobs":[],"obfuscation":"YZq9zsRja0g2M"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":48,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":":\n\n","logprobs":[],"obfuscation":"mhDAmaHJUvLGl"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":49,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"``","logprobs":[],"obfuscation":"3XmO5YTsWjzHHf"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":50,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"`\n","logprobs":[],"obfuscation":"4fmXZmdkPxNn8K"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":51,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"src","logprobs":[],"obfuscation":"ifGf4yLEg5pMZ"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":52,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"/L","logprobs":[],"obfuscation":"C1k1toBElpgxyW"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":53,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"ibraries","logprobs":[],"obfuscation":"fdOTYTyp"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":54,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"/M","logprobs":[],"obfuscation":"DyscJIQYaPJugC"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":55,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"icrosoft","logprobs":[],"obfuscation":"PQxU7muP"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":56,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":".Extensions","logprobs":[],"obfuscation":"RCJB8"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":57,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":".A","logprobs":[],"obfuscation":"i92CWxnAkwS4C9"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":58,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"I","logprobs":[],"obfuscation":"qfH8wVJN74vCfBM"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":59,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":".A","logprobs":[],"obfuscation":"LcuBP89lZVCCH9"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":60,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"bst","logprobs":[],"obfuscation":"I8rKDbKN0zylv"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":61,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"ractions","logprobs":[],"obfuscation":"tOgiCPs5"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":62,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"/","logprobs":[],"obfuscation":"jgJjLruTbFJGDhU"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":63,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"README","logprobs":[],"obfuscation":"D5VSEFNde7"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":64,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":".md","logprobs":[],"obfuscation":"7ZGJO5sZOTPBs"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":65,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"\n","logprobs":[],"obfuscation":"7Sv80haKTTwfEWj"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":66,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"``","logprobs":[],"obfuscation":"m1JSvZ8rrpJnH5"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":67,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"`\n\n","logprobs":[],"obfuscation":"U93PMKtCB5Pb5"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":68,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"This","logprobs":[],"obfuscation":"f5veTGedo9nM"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":69,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" file","logprobs":[],"obfuscation":"oEBwvP5FnPK"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":70,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" provides","logprobs":[],"obfuscation":"IVNCYwr"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":71,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" an","logprobs":[],"obfuscation":"3x6WquURIJ3ld"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":72,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" overview","logprobs":[],"obfuscation":"VR9yeiD"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":73,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" of","logprobs":[],"obfuscation":"z46dC1o2FC8Rs"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":74,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" the","logprobs":[],"obfuscation":"YfZGabvmgyoI"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":75,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" library","logprobs":[],"obfuscation":"TamElgEp"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":76,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":",","logprobs":[],"obfuscation":"VfVfqbnHAfsJyJn"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":77,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" installation","logprobs":[],"obfuscation":"CGR"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":78,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" instructions","logprobs":[],"obfuscation":"xst"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":79,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":",","logprobs":[],"obfuscation":"3u5wqRA2RXh2QP8"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":80,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" and","logprobs":[],"obfuscation":"tD4WZmOhepzQ"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":81,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" usage","logprobs":[],"obfuscation":"SadOK826mZ"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":82,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" examples","logprobs":[],"obfuscation":"5VpLKav"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":83,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" for","logprobs":[],"obfuscation":"xPvtjDSUic9E"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":84,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" its","logprobs":[],"obfuscation":"6duK61DX14vx"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":85,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" core","logprobs":[],"obfuscation":"Cz8trPLsCWu"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":86,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" components","logprobs":[],"obfuscation":"Gexuy"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":87,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":".","logprobs":[],"obfuscation":"HVeWkHoX1cc6hVh"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":88,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" If","logprobs":[],"obfuscation":"G1TOxxwvSEq4L"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":89,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" you","logprobs":[],"obfuscation":"xQlKeOixd1hv"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":90,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" have","logprobs":[],"obfuscation":"bX6P0qgFPnR"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":91,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" any","logprobs":[],"obfuscation":"KxH8EiMzXa1N"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":92,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" more","logprobs":[],"obfuscation":"kA0kxRPPqru"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":93,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" questions","logprobs":[],"obfuscation":"9HRCyD"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":94,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" about","logprobs":[],"obfuscation":"yYFZhtsSfc"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":95,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" it","logprobs":[],"obfuscation":"zpyEAwPWl8Ozh"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":96,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":",","logprobs":[],"obfuscation":"ivjn00lbmzDHiFU"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":97,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" feel","logprobs":[],"obfuscation":"O2edXDmkBqt"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":98,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" free","logprobs":[],"obfuscation":"MlpWh7p0P1F"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":99,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" to","logprobs":[],"obfuscation":"uMNfozGkKe6xW"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":100,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":" ask","logprobs":[],"obfuscation":"6rMOxwXhR8RY"}
+
+            event: response.output_text.delta
+            data: {"type":"response.output_text.delta","sequence_number":101,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"delta":"!","logprobs":[],"obfuscation":"QPZMdhS0e5vYuRl"}
+
+            event: response.output_text.done
+            data: {"type":"response.output_text.done","sequence_number":102,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"text":"The path to the `README.md` file for `Microsoft.Extensions.AI.Abstractions` in the `dotnet/extensions` repository is:\n\n```\nsrc/Libraries/Microsoft.Extensions.AI.Abstractions/README.md\n```\n\nThis file provides an overview of the library, installation instructions, and usage examples for its core components. If you have any more questions about it, feel free to ask!","logprobs":[]}
+
+            event: response.content_part.done
+            data: {"type":"response.content_part.done","sequence_number":103,"item_id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","output_index":3,"content_index":0,"part":{"type":"output_text","annotations":[],"logprobs":[],"text":"The path to the `README.md` file for `Microsoft.Extensions.AI.Abstractions` in the `dotnet/extensions` repository is:\n\n```\nsrc/Libraries/Microsoft.Extensions.AI.Abstractions/README.md\n```\n\nThis file provides an overview of the library, installation instructions, and usage examples for its core components. If you have any more questions about it, feel free to ask!"}}
+
+            event: response.output_item.done
+            data: {"type":"response.output_item.done","sequence_number":104,"output_index":3,"item":{"id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","type":"message","status":"completed","content":[{"type":"output_text","annotations":[],"logprobs":[],"text":"The path to the `README.md` file for `Microsoft.Extensions.AI.Abstractions` in the `dotnet/extensions` repository is:\n\n```\nsrc/Libraries/Microsoft.Extensions.AI.Abstractions/README.md\n```\n\nThis file provides an overview of the library, installation instructions, and usage examples for its core components. If you have any more questions about it, feel free to ask!"}],"role":"assistant"}}
+
+            event: response.completed
+            data: {"type":"response.completed","sequence_number":105,"response":{"id":"resp_68be44fd7298819e82fd82c8516e970d03a2537be0e84a54","object":"response","created_at":1757299965,"status":"completed","background":false,"error":null,"incomplete_details":null,"instructions":null,"max_output_tokens":null,"max_tool_calls":null,"model":"gpt-4o-mini-2024-07-18","output":[{"id":"mcpl_68be44fd8f68819eba7a74a2f6d27a5a03a2537be0e84a54","type":"mcp_list_tools","server_label":"deepwiki","tools":[{"annotations":{"read_only":false},"description":"Get a list of documentation topics for a GitHub repository","input_schema":{"type":"object","properties":{"repoName":{"type":"string","description":"GitHub repository: owner/repo (e.g. \"facebook/react\")"}},"required":["repoName"],"additionalProperties":false,"$schema":"http://json-schema.org/draft-07/schema#"},"name":"read_wiki_structure"},{"annotations":{"read_only":false},"description":"View documentation about a GitHub repository","input_schema":{"type":"object","properties":{"repoName":{"type":"string","description":"GitHub repository: owner/repo (e.g. \"facebook/react\")"}},"required":["repoName"],"additionalProperties":false,"$schema":"http://json-schema.org/draft-07/schema#"},"name":"read_wiki_contents"},{"annotations":{"read_only":false},"description":"Ask any question about a GitHub repository","input_schema":{"type":"object","properties":{"repoName":{"type":"string","description":"GitHub repository: owner/repo (e.g. \"facebook/react\")"},"question":{"type":"string","description":"The question to ask about the repository"}},"required":["repoName","question"],"additionalProperties":false,"$schema":"http://json-schema.org/draft-07/schema#"},"name":"ask_question"}]},{"id":"mcp_68be4503d45c819e89cb574361c8eba003a2537be0e84a54","type":"mcp_call","approval_request_id":null,"arguments":"{\"repoName\":\"dotnet/extensions\"}","error":null,"name":"read_wiki_structure","output":"Available pages for dotnet/extensions:\n\n- 1 Overview\n- 2 Build System and CI/CD\n- 3 AI Extensions Framework\n  - 3.1 Core Abstractions\n  - 3.2 AI Function System\n  - 3.3 Chat Completion\n  - 3.4 Caching System\n  - 3.5 Evaluation and Reporting\n- 4 HTTP Resilience and Diagnostics\n  - 4.1 Standard Resilience\n  - 4.2 Hedging Strategies\n- 5 Telemetry and Compliance\n- 6 Testing Infrastructure\n  - 6.1 AI Service Integration Testing\n  - 6.2 Time Provider Testing","server_label":"deepwiki"},{"id":"mcp_68be4505f134819e806c002f27cce0c303a2537be0e84a54","type":"mcp_call","approval_request_id":null,"arguments":"{\"repoName\":\"dotnet/extensions\",\"question\":\"What is the path to the README.md file for Microsoft.Extensions.AI.Abstractions?\"}","error":null,"name":"ask_question","output":"The path to the `README.md` file for `Microsoft.Extensions.AI.Abstractions` is `src/Libraries/Microsoft.Extensions.AI.Abstractions/README.md` . This file provides an overview of the `Microsoft.Extensions.AI.Abstractions` library, including installation instructions and usage examples for its core components like `IChatClient` and `IEmbeddingGenerator`   .\n\n## README.md Content Overview\nThe `README.md` file for `Microsoft.Extensions.AI.Abstractions` details the purpose of the library, which is to provide abstractions for generative AI components . It includes instructions on how to install the NuGet package `Microsoft.Extensions.AI.Abstractions` .\n\nThe document also provides usage examples for the `IChatClient` interface, which defines methods for interacting with AI services that offer \"chat\" capabilities . This includes examples for requesting both complete and streaming chat responses  .\n\nFurthermore, the `README.md` explains the `IEmbeddingGenerator` interface, which is used for generating vector embeddings from input values . It demonstrates how to use `GenerateAsync` to create embeddings . The file also discusses how both `IChatClient` and `IEmbeddingGenerator` implementations can be layered to create pipelines of functionality, incorporating features like caching and telemetry  .\n\nNotes:\nThe user's query specifically asked for the path to the `README.md` file for `Microsoft.Extensions.AI.Abstractions`. The provided codebase context, particularly the wiki page for \"AI Extensions Framework\", directly lists this file as a relevant source file . The content of the `README.md` file itself further confirms its relevance to the `Microsoft.Extensions.AI.Abstractions` library.\n\nWiki pages you might want to explore:\n- [AI Extensions Framework (dotnet/extensions)](/wiki/dotnet/extensions#3)\n- [Chat Completion (dotnet/extensions)](/wiki/dotnet/extensions#3.3)\n\nView this search on DeepWiki: https://deepwiki.com/search/what-is-the-path-to-the-readme_bb6bee43-3136-4b21-bc5d-02ca1611d857\n","server_label":"deepwiki"},{"id":"msg_68be450c39e8819eb9bf6fcb9fd16ecb03a2537be0e84a54","type":"message","status":"completed","content":[{"type":"output_text","annotations":[],"logprobs":[],"text":"The path to the `README.md` file for `Microsoft.Extensions.AI.Abstractions` in the `dotnet/extensions` repository is:\n\n```\nsrc/Libraries/Microsoft.Extensions.AI.Abstractions/README.md\n```\n\nThis file provides an overview of the library, installation instructions, and usage examples for its core components. If you have any more questions about it, feel free to ask!"}],"role":"assistant"}],"parallel_tool_calls":true,"previous_response_id":null,"prompt_cache_key":null,"reasoning":{"effort":null,"summary":null},"safety_identifier":null,"service_tier":"default","store":true,"temperature":1.0,"text":{"format":{"type":"text"},"verbosity":"medium"},"tool_choice":"auto","tools":[{"type":"mcp","allowed_tools":null,"headers":null,"require_approval":"never","server_description":null,"server_label":"deepwiki","server_url":"https://mcp.deepwiki.com/<redacted>"}],"top_logprobs":0,"top_p":1.0,"truncation":"disabled","usage":{"input_tokens":1420,"input_tokens_details":{"cached_tokens":0},"output_tokens":149,"output_tokens_details":{"reasoning_tokens":0},"total_tokens":1569},"user":null,"metadata":{}}}
+            
+            
+            """;
+
+        using VerbatimHttpHandler handler = new(Input, Output);
+        using HttpClient httpClient = new(handler);
+        using IChatClient client = CreateResponseClient(httpClient, "gpt-4o-mini");
+
+        ChatOptions chatOptions = new()
+        {
+            Tools = [new HostedMcpServerTool("deepwiki", "https://mcp.deepwiki.com/mcp")
+                {
+                    ApprovalMode = HostedMcpServerToolApprovalMode.NeverRequire,
+                }
+            ],
+        };
+
+        var response = await client.GetStreamingResponseAsync("Tell me the path to the README.md file for Microsoft.Extensions.AI.Abstractions in the dotnet/extensions repository", chatOptions)
+            .ToChatResponseAsync();
+        Assert.NotNull(response);
+
+        Assert.Equal("resp_68be44fd7298819e82fd82c8516e970d03a2537be0e84a54", response.ResponseId);
+        Assert.Equal("resp_68be44fd7298819e82fd82c8516e970d03a2537be0e84a54", response.ConversationId);
+        Assert.Equal("gpt-4o-mini-2024-07-18", response.ModelId);
+        Assert.Equal(DateTimeOffset.FromUnixTimeSeconds(1_757_299_965), response.CreatedAt);
+        Assert.Equal(ChatFinishReason.Stop, response.FinishReason);
+
+        var message = Assert.Single(response.Messages);
+        Assert.Equal(ChatRole.Assistant, response.Messages[0].Role);
+        Assert.StartsWith("The path to the `README.md` file", response.Messages[0].Text);
+
+        Assert.Equal(6, message.Contents.Count);
+
+        var firstCall = Assert.IsType<McpServerToolCallContent>(message.Contents[1]);
+        Assert.Equal("mcp_68be4503d45c819e89cb574361c8eba003a2537be0e84a54", firstCall.CallId);
+        Assert.Equal("deepwiki", firstCall.ServerName);
+        Assert.Equal("read_wiki_structure", firstCall.ToolName);
+        Assert.NotNull(firstCall.Arguments);
+        Assert.Single(firstCall.Arguments);
+        Assert.Equal("dotnet/extensions", ((JsonElement)firstCall.Arguments["repoName"]!).GetString());
+
+        var firstResult = Assert.IsType<McpServerToolResultContent>(message.Contents[2]);
+        Assert.Equal("mcp_68be4503d45c819e89cb574361c8eba003a2537be0e84a54", firstResult.CallId);
+        Assert.NotNull(firstResult.Output);
+        Assert.StartsWith("Available pages for dotnet/extensions", Assert.IsType<TextContent>(Assert.Single(firstResult.Output)).Text);
+
+        var secondCall = Assert.IsType<McpServerToolCallContent>(message.Contents[3]);
+        Assert.Equal("mcp_68be4505f134819e806c002f27cce0c303a2537be0e84a54", secondCall.CallId);
+        Assert.Equal("deepwiki", secondCall.ServerName);
+        Assert.Equal("ask_question", secondCall.ToolName);
+        Assert.NotNull(secondCall.Arguments);
+        Assert.Equal("dotnet/extensions", ((JsonElement)secondCall.Arguments["repoName"]!).GetString());
+        Assert.Equal("What is the path to the README.md file for Microsoft.Extensions.AI.Abstractions?", ((JsonElement)secondCall.Arguments["question"]!).GetString());
+
+        var secondResult = Assert.IsType<McpServerToolResultContent>(message.Contents[4]);
+        Assert.Equal("mcp_68be4505f134819e806c002f27cce0c303a2537be0e84a54", secondResult.CallId);
+        Assert.NotNull(secondResult.Output);
+        Assert.StartsWith("The path to the `README.md` file", Assert.IsType<TextContent>(Assert.Single(secondResult.Output)).Text);
+
+        Assert.NotNull(response.Usage);
+        Assert.Equal(1420, response.Usage.InputTokenCount);
+        Assert.Equal(149, response.Usage.OutputTokenCount);
+        Assert.Equal(1569, response.Usage.TotalTokenCount);
+    }
+
     private static IChatClient CreateResponseClient(HttpClient httpClient, string modelId) =>
         new OpenAIClient(
             new ApiKeyCredential("apikey"),

From 759d1fc02fd034b4c1854d3d6cac7d2db956acb8 Mon Sep 17 00:00:00 2001
From: Stephen Toub <stoub@microsoft.com>
Date: Mon, 8 Sep 2025 16:36:54 -0400
Subject: [PATCH 8/8] Remove Microsoft.Bcl.HashCode package reference from
 M.E.AI.Abstractions (#6780)

* Remove Microsoft.Bcl.HashCode package reference from M.E.AI.Abstractions

It was added unexpectedly.

Also added a changelog entry on the MCP support
---
 .../CHANGELOG.md                              |  1 +
 ...cpServerToolRequireSpecificApprovalMode.cs | 29 ++++++++++--
 ...icrosoft.Extensions.AI.Abstractions.csproj |  1 -
 .../CHANGELOG.md                              |  2 +-
 .../HostedMcpServerToolApprovalModeTests.cs   | 47 +++++++++++++++++++
 5 files changed, 75 insertions(+), 5 deletions(-)

diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/CHANGELOG.md b/src/Libraries/Microsoft.Extensions.AI.Abstractions/CHANGELOG.md
index 34c83f701c1..37ffe79f892 100644
--- a/src/Libraries/Microsoft.Extensions.AI.Abstractions/CHANGELOG.md
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 - Added non-invocable `AIFunctionDeclaration` (base class for `AIFunction`), `AIFunctionFactory.CreateDeclaration`, and `AIFunction.AsDeclarationOnly`.
 - Added `[Experimental]` support for user approval of function invocations via `ApprovalRequiredAIFunction`, `FunctionApprovalRequestContent`, and friends.
+- Added `[Experimental]` support for MCP server-hosted tools via `HostedMcpServerTool`, `HostedMcpServerToolApprovalMode`, and friends.
 
 ## 9.8.0
 
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedMcpServerToolRequireSpecificApprovalMode.cs b/src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedMcpServerToolRequireSpecificApprovalMode.cs
index a5e870af7e7..42a39f35c50 100644
--- a/src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedMcpServerToolRequireSpecificApprovalMode.cs
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedMcpServerToolRequireSpecificApprovalMode.cs
@@ -6,6 +6,9 @@
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 
+#pragma warning disable S109 // Magic numbers should not be used
+#pragma warning disable EA0011 // Consider removing unnecessary conditional access operator (?)
+
 namespace Microsoft.Extensions.AI;
 
 /// <summary>
@@ -42,7 +45,7 @@ public override bool Equals(object? obj) => obj is HostedMcpServerToolRequireSpe
 
     /// <inheritdoc/>
     public override int GetHashCode() =>
-        HashCode.Combine(GetListHashCode(AlwaysRequireApprovalToolNames), GetListHashCode(NeverRequireApprovalToolNames));
+        Combine(GetListHashCode(AlwaysRequireApprovalToolNames), GetListHashCode(NeverRequireApprovalToolNames));
 
     private static bool ListEquals(IList<string>? list1, IList<string>? list2) =>
         ReferenceEquals(list1, list2) ||
@@ -55,12 +58,32 @@ private static int GetListHashCode(IList<string>? list)
             return 0;
         }
 
+#if NET
         HashCode hc = default;
-        foreach (string item in list)
+        for (int i = 0; i < list.Count; i++)
         {
-            hc.Add(item);
+            hc.Add(list[i]);
         }
 
         return hc.ToHashCode();
+#else
+        int hash = 0;
+        for (int i = 0; i < list.Count; i++)
+        {
+            hash = Combine(hash, list[i]?.GetHashCode() ?? 0);
+        }
+
+        return hash;
+#endif
+    }
+
+    private static int Combine(int h1, int h2)
+    {
+#if NET
+        return HashCode.Combine(h1, h2);
+#else
+        uint rol5 = ((uint)h1 << 5) | ((uint)h1 >> 27);
+        return ((int)rol5 + h1) ^ h2;
+#endif
     }
 }
diff --git a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Microsoft.Extensions.AI.Abstractions.csproj b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Microsoft.Extensions.AI.Abstractions.csproj
index 25aa2f4c49d..f5472854def 100644
--- a/src/Libraries/Microsoft.Extensions.AI.Abstractions/Microsoft.Extensions.AI.Abstractions.csproj
+++ b/src/Libraries/Microsoft.Extensions.AI.Abstractions/Microsoft.Extensions.AI.Abstractions.csproj
@@ -32,7 +32,6 @@
 
   <ItemGroup Condition="'$(TargetFrameworkIdentifier)' != '.NETCoreApp'">
     <PackageReference Include="System.Text.Json" />
-    <PackageReference Include="Microsoft.Bcl.HashCode" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'net462'">
diff --git a/src/Libraries/Microsoft.Extensions.AI.OpenAI/CHANGELOG.md b/src/Libraries/Microsoft.Extensions.AI.OpenAI/CHANGELOG.md
index 15859a5744d..ded1e85533f 100644
--- a/src/Libraries/Microsoft.Extensions.AI.OpenAI/CHANGELOG.md
+++ b/src/Libraries/Microsoft.Extensions.AI.OpenAI/CHANGELOG.md
@@ -2,9 +2,9 @@
 
 ## NOT YET RELEASED
 
+- Updated to depend on OpenAI 2.4.0
 - Updated tool mappings to recognize any `AIFunctionDeclaration`.
 - Updated to accommodate the additions in `Microsoft.Extensions.AI.Abstractions`.
-- Updated to depend on OpenAI 2.4.0
 
 ## 9.8.0-preview.1.25412.6
 
diff --git a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/HostedMcpServerToolApprovalModeTests.cs b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/HostedMcpServerToolApprovalModeTests.cs
index 3ad4690130a..9f72a194f06 100644
--- a/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/HostedMcpServerToolApprovalModeTests.cs
+++ b/test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/HostedMcpServerToolApprovalModeTests.cs
@@ -45,4 +45,51 @@ public void Serialization_RequireSpecific_Roundtrips()
         HostedMcpServerToolApprovalMode? result = JsonSerializer.Deserialize(json, TestJsonSerializerContext.Default.HostedMcpServerToolApprovalMode);
         Assert.Equal(requireSpecific, result);
     }
+
+    [Fact]
+    public void Equality_RequireSpecific_WorksAsExpected()
+    {
+        var mode1 = HostedMcpServerToolApprovalMode.RequireSpecific(["ToolA", "ToolB"], ["ToolC"]);
+        var mode2 = HostedMcpServerToolApprovalMode.RequireSpecific(["ToolA", "ToolB"], ["ToolC"]);
+        Assert.Equal(mode1, mode2);
+        Assert.Equal(mode1.GetHashCode(), mode2.GetHashCode());
+
+        Assert.NotNull(mode1.AlwaysRequireApprovalToolNames);
+        mode1.AlwaysRequireApprovalToolNames.Add("ToolD");
+        Assert.NotEqual(mode1, mode2);
+        Assert.NotEqual(mode1.GetHashCode(), mode2.GetHashCode());
+
+        Assert.NotNull(mode2.AlwaysRequireApprovalToolNames);
+        mode2.AlwaysRequireApprovalToolNames.Add("ToolD");
+        Assert.Equal(mode1, mode2);
+        Assert.Equal(mode1.GetHashCode(), mode2.GetHashCode());
+
+        Assert.NotNull(mode2.NeverRequireApprovalToolNames);
+        mode2.NeverRequireApprovalToolNames.Add("ToolE");
+        Assert.NotEqual(mode1, mode2);
+        Assert.NotEqual(mode1.GetHashCode(), mode2.GetHashCode());
+
+        Assert.NotNull(mode1.NeverRequireApprovalToolNames);
+        mode1.NeverRequireApprovalToolNames.Add("ToolE");
+        Assert.Equal(mode1, mode2);
+        Assert.Equal(mode1.GetHashCode(), mode2.GetHashCode());
+
+        var mode3 = HostedMcpServerToolApprovalMode.RequireSpecific(null, null);
+        Assert.Equal(mode3.GetHashCode(), mode3.GetHashCode());
+        var mode4 = HostedMcpServerToolApprovalMode.RequireSpecific(["a"], null);
+        Assert.Equal(mode4.GetHashCode(), mode4.GetHashCode());
+        Assert.NotEqual(mode3, mode4);
+        Assert.NotEqual(mode3.GetHashCode(), mode4.GetHashCode());
+
+        var mode5 = HostedMcpServerToolApprovalMode.RequireSpecific(null, ["b"]);
+        Assert.Equal(mode5.GetHashCode(), mode5.GetHashCode());
+        Assert.NotEqual(mode3, mode5);
+        Assert.NotEqual(mode3.GetHashCode(), mode5.GetHashCode());
+        Assert.NotEqual(mode4, mode5);
+        Assert.NotEqual(mode4.GetHashCode(), mode5.GetHashCode());
+
+        var mode6 = HostedMcpServerToolApprovalMode.RequireSpecific([], []);
+        Assert.Equal(mode6.GetHashCode(), mode6.GetHashCode());
+        Assert.NotEqual(mode3, mode6);
+    }
 }