diff --git a/extensions/src/AWSSDK.Extensions.Bedrock.MEAI/AWSSDK.Extensions.Bedrock.MEAI.NetFramework.csproj b/extensions/src/AWSSDK.Extensions.Bedrock.MEAI/AWSSDK.Extensions.Bedrock.MEAI.NetFramework.csproj
index df6d55e9e4e6..446626bb8afa 100644
--- a/extensions/src/AWSSDK.Extensions.Bedrock.MEAI/AWSSDK.Extensions.Bedrock.MEAI.NetFramework.csproj
+++ b/extensions/src/AWSSDK.Extensions.Bedrock.MEAI/AWSSDK.Extensions.Bedrock.MEAI.NetFramework.csproj
@@ -37,7 +37,7 @@
   </Choose>
   
   <ItemGroup>
-    <PackageReference Include="Microsoft.Extensions.AI.Abstractions" Version="9.9.0" />
+    <PackageReference Include="Microsoft.Extensions.AI.Abstractions" Version="9.9.1" />
   </ItemGroup>
   
   <ItemGroup>
diff --git a/extensions/src/AWSSDK.Extensions.Bedrock.MEAI/AWSSDK.Extensions.Bedrock.MEAI.NetStandard.csproj b/extensions/src/AWSSDK.Extensions.Bedrock.MEAI/AWSSDK.Extensions.Bedrock.MEAI.NetStandard.csproj
index dde3ae6c2422..97b1a20a55e0 100644
--- a/extensions/src/AWSSDK.Extensions.Bedrock.MEAI/AWSSDK.Extensions.Bedrock.MEAI.NetStandard.csproj
+++ b/extensions/src/AWSSDK.Extensions.Bedrock.MEAI/AWSSDK.Extensions.Bedrock.MEAI.NetStandard.csproj
@@ -41,7 +41,7 @@
   </Choose>
   
   <ItemGroup>
-  <PackageReference Include="Microsoft.Extensions.AI.Abstractions" Version="9.9.0" />
+  <PackageReference Include="Microsoft.Extensions.AI.Abstractions" Version="9.9.1" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/extensions/src/AWSSDK.Extensions.Bedrock.MEAI/AWSSDK.Extensions.Bedrock.MEAI.nuspec b/extensions/src/AWSSDK.Extensions.Bedrock.MEAI/AWSSDK.Extensions.Bedrock.MEAI.nuspec
index 22332ee1dca9..789856e6db3a 100644
--- a/extensions/src/AWSSDK.Extensions.Bedrock.MEAI/AWSSDK.Extensions.Bedrock.MEAI.nuspec
+++ b/extensions/src/AWSSDK.Extensions.Bedrock.MEAI/AWSSDK.Extensions.Bedrock.MEAI.nuspec
@@ -15,17 +15,17 @@
       <group targetFramework="net472">
         <dependency id="AWSSDK.Core" version="4.0.1.3" />
         <dependency id="AWSSDK.BedrockRuntime" version="4.0.7.7" />
-        <dependency id="Microsoft.Extensions.AI.Abstractions" version="9.9.0" />
+        <dependency id="Microsoft.Extensions.AI.Abstractions" version="9.9.1" />
       </group>
       <group targetFramework="netstandard2.0">
         <dependency id="AWSSDK.Core" version="4.0.1.3" />
         <dependency id="AWSSDK.BedrockRuntime" version="4.0.7.7" />
-        <dependency id="Microsoft.Extensions.AI.Abstractions" version="9.9.0" />
+        <dependency id="Microsoft.Extensions.AI.Abstractions" version="9.9.1" />
       </group>
       <group targetFramework="net8.0">
         <dependency id="AWSSDK.Core" version="4.0.1.3" />
         <dependency id="AWSSDK.BedrockRuntime" version="4.0.7.7" />
-        <dependency id="Microsoft.Extensions.AI.Abstractions" version="9.9.0" />
+        <dependency id="Microsoft.Extensions.AI.Abstractions" version="9.9.1" />
       </group>
     </dependencies>
   </metadata>
diff --git a/extensions/src/AWSSDK.Extensions.Bedrock.MEAI/BedrockChatClient.cs b/extensions/src/AWSSDK.Extensions.Bedrock.MEAI/BedrockChatClient.cs
index 0479bc878232..bfe33dbda368 100644
--- a/extensions/src/AWSSDK.Extensions.Bedrock.MEAI/BedrockChatClient.cs
+++ b/extensions/src/AWSSDK.Extensions.Bedrock.MEAI/BedrockChatClient.cs
@@ -121,7 +121,7 @@ public async Task<ChatResponse> GetResponseAsync(
 
                     if (reasoningContent.ReasoningText.Signature is string signature)
                     {
-                        (trc.AdditionalProperties ??= [])[nameof(reasoningContent.ReasoningText.Signature)] = signature;
+                        trc.ProtectedData = signature;
                     }
 
                     if (reasoningContent.RedactedContent is { } redactedContent)
@@ -249,13 +249,13 @@ public async IAsyncEnumerable<ChatResponseUpdate> GetStreamingResponseAsync(
                         yield return textUpdate;
                     }
 
-                    if (contentBlockDelta.Delta.ReasoningContent is { Text: not null } reasoningContent)
+                    if (contentBlockDelta.Delta.ReasoningContent is { } reasoningContent)
                     {
                         TextReasoningContent trc = new(reasoningContent.Text);
 
                         if (reasoningContent.Signature is not null)
                         {
-                            (trc.AdditionalProperties ??= [])[nameof(reasoningContent.Signature)] = reasoningContent.Signature;
+                            trc.ProtectedData = reasoningContent.Signature;
                         }
 
                         if (reasoningContent.RedactedContent is { } redactedContent)
@@ -516,6 +516,8 @@ private static List<ContentBlock> CreateContents(ChatMessage message)
                     break;
 
                 case TextReasoningContent trc:
+                    object? redactedContent = null;
+                    trc.AdditionalProperties?.TryGetValue(nameof(ReasoningContentBlock.RedactedContent), out redactedContent);
                     contents.Add(new()
                     {
                         ReasoningContent = new()
@@ -523,9 +525,9 @@ private static List<ContentBlock> CreateContents(ChatMessage message)
                             ReasoningText = new()
                             {
                                 Text = trc.Text,
-                                Signature = trc.AdditionalProperties?[nameof(ReasoningContentBlock.ReasoningText.Signature)] as string,
+                                Signature = trc.ProtectedData,
                             },
-                            RedactedContent = trc.AdditionalProperties?[nameof(ReasoningContentBlock.RedactedContent)] is byte[] array ? new(array) : null,
+                            RedactedContent = redactedContent is byte[] array ? new(array) : null,
                         }
                     });
                     break;
diff --git a/extensions/test/BedrockMEAITests/BedrockMEAITests.NetFramework.csproj b/extensions/test/BedrockMEAITests/BedrockMEAITests.NetFramework.csproj
index 42c9d80ffa65..dd9de35ce4a5 100644
--- a/extensions/test/BedrockMEAITests/BedrockMEAITests.NetFramework.csproj
+++ b/extensions/test/BedrockMEAITests/BedrockMEAITests.NetFramework.csproj
@@ -18,7 +18,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.Extensions.AI.Abstractions" Version="9.9.0" />
+    <PackageReference Include="Microsoft.Extensions.AI.Abstractions" Version="9.9.1" />
     <PackageReference Include="xunit" Version="2.9.2" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2" />
   </ItemGroup>
diff --git a/generator/.DevConfigs/6c035145-4fe4-42cd-9339-4f10256de2e7.json b/generator/.DevConfigs/6c035145-4fe4-42cd-9339-4f10256de2e7.json
new file mode 100644
index 000000000000..25da818f4561
--- /dev/null
+++ b/generator/.DevConfigs/6c035145-4fe4-42cd-9339-4f10256de2e7.json
@@ -0,0 +1,11 @@
+{
+  "extensions": [
+    {
+      "extensionName": "Extensions.Bedrock.MEAI",
+      "type": "patch",
+      "changeLogMessages": [
+        "Fix reading/writing ReasoningContent for tool use."
+      ]
+    }
+  ]
+}
\ No newline at end of file