diff --git a/src/Clients/Goa.Clients.Bedrock.Conversation.Dynamo/DynamoConversationStore.cs b/src/Clients/Goa.Clients.Bedrock.Conversation.Dynamo/DynamoConversationStore.cs
index 35a739a8..dda4583f 100644
--- a/src/Clients/Goa.Clients.Bedrock.Conversation.Dynamo/DynamoConversationStore.cs
+++ b/src/Clients/Goa.Clients.Bedrock.Conversation.Dynamo/DynamoConversationStore.cs
@@ -63,7 +63,7 @@ public DynamoConversationStore(IDynamoClient dynamoClient, DynamoConversationSto
         var conversationId = Guid.CreateVersion7().ToString("N");
         var now = DateTimeOffset.UtcNow;
 
-        var item = new Dictionary<string, AttributeValue>
+        var item = new Dictionary<string, AttributeValue>(8)
         {
             [_configuration.PartitionKeyName] = _configuration.ConversationPkFormat(conversationId),
             [_configuration.SortKeyName] = _configuration.ConversationSkValue,
@@ -111,7 +111,7 @@ public DynamoConversationStore(IDynamoClient dynamoClient, DynamoConversationSto
         var request = new GetItemRequest
         {
             TableName = _configuration.TableName,
-            Key = new Dictionary<string, AttributeValue>
+            Key = new Dictionary<string, AttributeValue>(2)
             {
                 [_configuration.PartitionKeyName] = _configuration.ConversationPkFormat(conversationId),
                 [_configuration.SortKeyName] = _configuration.ConversationSkValue
@@ -145,7 +145,7 @@ public async Task<ErrorOr<ConversationWithMessages>> GetConversationWithMessages
         {
             TableName = _configuration.TableName,
             KeyConditionExpression = $"{_configuration.PartitionKeyName} = :pk AND begins_with({_configuration.SortKeyName}, :skPrefix)",
-            ExpressionAttributeValues = new Dictionary<string, AttributeValue>
+            ExpressionAttributeValues = new Dictionary<string, AttributeValue>(2)
             {
                 [":pk"] = _configuration.ConversationPkFormat(conversationId),
                 [":skPrefix"] = _configuration.MessageSkPrefix
@@ -212,10 +212,10 @@ public Task<ErrorOr<IReadOnlyList<ConversationMessage>>> AddMessagesAsync(
         IEnumerable<(ConversationRole Role, Message Message, TokenUsage? TokenUsage)> messages,
         CancellationToken ct)
     {
-        return AddMessagesInternalAsync(
-            conversationId,
-            messages.Select(m => (m.Role, m.Message, m.TokenUsage, (IReadOnlyDictionary<string, IReadOnlyList<string>>?)null)),
-            ct);
+        var expanded = new List<(ConversationRole Role, Message Message, TokenUsage? TokenUsage, IReadOnlyDictionary<string, IReadOnlyList<string>>? ExtractedTags)>();
+        foreach (var m in messages)
+            expanded.Add((m.Role, m.Message, m.TokenUsage, null));
+        return AddMessagesInternalAsync(conversationId, expanded, ct);
     }
 
     private async Task<ErrorOr<IReadOnlyList<ConversationMessage>>> AddMessagesInternalAsync(
@@ -223,7 +223,7 @@ private async Task<ErrorOr<IReadOnlyList<ConversationMessage>>> AddMessagesInter
         IEnumerable<(ConversationRole Role, Message Message, TokenUsage? TokenUsage, IReadOnlyDictionary<string, IReadOnlyList<string>>? ExtractedTags)> messages,
         CancellationToken ct)
     {
-        var messageList = messages.ToList();
+        var messageList = new List<(ConversationRole Role, Message Message, TokenUsage? TokenUsage, IReadOnlyDictionary<string, IReadOnlyList<string>>? ExtractedTags)>(messages);
         if (messageList.Count == 0)
             return Error.Validation(ConversationErrorCodes.MessagesEmpty, "At least one message must be provided");
 
@@ -255,7 +255,7 @@ private async Task<ErrorOr<IReadOnlyList<ConversationMessage>>> AddMessagesInter
             var sequenceNumber = startSequence + i;
             var messageId = Guid.NewGuid().ToString("N");
 
-            var messageItem = new Dictionary<string, AttributeValue>
+            var messageItem = new Dictionary<string, AttributeValue>(12)
             {
                 [_configuration.PartitionKeyName] = _configuration.ConversationPkFormat(conversationId),
                 [_configuration.SortKeyName] = _configuration.MessageSkFormat(conversationId, sequenceNumber),
@@ -292,7 +292,7 @@ private async Task<ErrorOr<IReadOnlyList<ConversationMessage>>> AddMessagesInter
             // Add extracted tags if present
             if (extractedTags is not null && extractedTags.Count > 0)
             {
-                var tagsMap = new Dictionary<string, AttributeValue>();
+                var tagsMap = new Dictionary<string, AttributeValue>(extractedTags.Count);
                 foreach (var kvp in extractedTags)
                 {
                     var tagValues = new List<AttributeValue>();
@@ -335,13 +335,13 @@ private async Task<ErrorOr<IReadOnlyList<ConversationMessage>>> AddMessagesInter
         }
 
         // Build update expression for conversation
-        var updateParts = new List<string>
+        var updateParts = new List<string>(5)
         {
             $"{MessageCountAttribute} = {MessageCountAttribute} + :msgCount",
             $"{UpdatedAtAttribute} = :updatedAt"
         };
 
-        var updateExpressionValues = new Dictionary<string, AttributeValue>
+        var updateExpressionValues = new Dictionary<string, AttributeValue>(6)
         {
             [":msgCount"] = AttributeValue.Number(messageList.Count.ToString()),
             [":updatedAt"] = AttributeValue.Number(now.ToUnixTimeSeconds().ToString())
@@ -363,7 +363,7 @@ private async Task<ErrorOr<IReadOnlyList<ConversationMessage>>> AddMessagesInter
             Update = new TransactUpdateItem
             {
                 TableName = _configuration.TableName,
-                Key = new Dictionary<string, AttributeValue>
+                Key = new Dictionary<string, AttributeValue>(2)
                 {
                     [_configuration.PartitionKeyName] = _configuration.ConversationPkFormat(conversationId),
                     [_configuration.SortKeyName] = _configuration.ConversationSkValue
@@ -393,12 +393,12 @@ private async Task<ErrorOr<IReadOnlyList<ConversationMessage>>> AddMessagesInter
     {
         var now = DateTimeOffset.UtcNow;
 
-        var updateParts = new List<string> { $"{UpdatedAtAttribute} = :updatedAt" };
-        var expressionAttributeValues = new Dictionary<string, AttributeValue>
+        var updateParts = new List<string>(4) { $"{UpdatedAtAttribute} = :updatedAt" };
+        var expressionAttributeValues = new Dictionary<string, AttributeValue>(4)
         {
             [":updatedAt"] = AttributeValue.Number(now.ToUnixTimeSeconds().ToString())
         };
-        var expressionAttributeNames = new Dictionary<string, string>();
+        var expressionAttributeNames = new Dictionary<string, string>(1);
 
         if (metadata.Title is not null)
         {
@@ -422,7 +422,7 @@ private async Task<ErrorOr<IReadOnlyList<ConversationMessage>>> AddMessagesInter
         {
             updateParts.Add($"#customData = :customData");
             expressionAttributeNames["#customData"] = CustomDataAttribute;
-            var customDataMap = new Dictionary<string, AttributeValue>();
+            var customDataMap = new Dictionary<string, AttributeValue>(metadata.CustomData.Count);
             foreach (var kvp in metadata.CustomData)
             {
                 customDataMap[kvp.Key] = kvp.Value;
@@ -433,7 +433,7 @@ private async Task<ErrorOr<IReadOnlyList<ConversationMessage>>> AddMessagesInter
         var updateRequest = new UpdateItemRequest
         {
             TableName = _configuration.TableName,
-            Key = new Dictionary<string, AttributeValue>
+            Key = new Dictionary<string, AttributeValue>(2)
             {
                 [_configuration.PartitionKeyName] = _configuration.ConversationPkFormat(conversationId),
                 [_configuration.SortKeyName] = _configuration.ConversationSkValue
@@ -469,7 +469,7 @@ public async Task<ErrorOr<Deleted>> DeleteConversationAsync(string conversationI
             {
                 TableName = _configuration.TableName,
                 KeyConditionExpression = $"{_configuration.PartitionKeyName} = :pk",
-                ExpressionAttributeValues = new Dictionary<string, AttributeValue>
+                ExpressionAttributeValues = new Dictionary<string, AttributeValue>(1)
                 {
                     [":pk"] = pk
                 }
@@ -486,7 +486,7 @@ public async Task<ErrorOr<Deleted>> DeleteConversationAsync(string conversationI
 
             foreach (var item in queryResult.Value.Items)
             {
-                allItems.Add(new Dictionary<string, AttributeValue>
+                allItems.Add(new Dictionary<string, AttributeValue>(2)
                 {
                     [_configuration.PartitionKeyName] = item[_configuration.PartitionKeyName]!.Value,
                     [_configuration.SortKeyName] = item[_configuration.SortKeyName]!.Value
@@ -503,15 +503,19 @@ public async Task<ErrorOr<Deleted>> DeleteConversationAsync(string conversationI
         const int batchSize = 25;
         for (var i = 0; i < allItems.Count; i += batchSize)
         {
-            var batch = allItems.Skip(i).Take(batchSize).ToList();
-            var transactItems = batch.Select(key => new TransactWriteItem
+            var end = Math.Min(i + batchSize, allItems.Count);
+            var transactItems = new List<TransactWriteItem>(end - i);
+            for (var j = i; j < end; j++)
             {
-                Delete = new TransactDeleteItem
+                transactItems.Add(new TransactWriteItem
                 {
-                    TableName = _configuration.TableName,
-                    Key = key
-                }
-            }).ToList();
+                    Delete = new TransactDeleteItem
+                    {
+                        TableName = _configuration.TableName,
+                        Key = allItems[j]
+                    }
+                });
+            }
 
             var transactRequest = new TransactWriteRequest
             {
@@ -539,7 +543,7 @@ private static void SerializeMetadata(ConversationMetadata metadata, Dictionary<
 
         if (metadata.CustomData.Count > 0)
         {
-            var customDataMap = new Dictionary<string, AttributeValue>();
+            var customDataMap = new Dictionary<string, AttributeValue>(metadata.CustomData.Count);
             foreach (var kvp in metadata.CustomData)
             {
                 customDataMap[kvp.Key] = kvp.Value;
@@ -607,7 +611,7 @@ private static void SerializeMetadata(ConversationMetadata metadata, Dictionary<
 
         if (record.TryGetStringSet(TagsAttribute, out var tags))
         {
-            metadata.Tags = tags.ToList();
+            metadata.Tags = new List<string>(tags);
             hasMetadata = true;
         }
 
@@ -665,7 +669,7 @@ private ErrorOr<ConversationMessage> DeserializeMessage(DynamoRecord record)
         IReadOnlyDictionary<string, IReadOnlyList<string>>? extractedTags = null;
         if (record.TryGetMap(ExtractedTagsAttribute, out var tagsMap) && tagsMap is not null)
         {
-            var tags = new Dictionary<string, IReadOnlyList<string>>();
+            var tags = new Dictionary<string, IReadOnlyList<string>>(tagsMap.Count);
             foreach (var kvp in tagsMap)
             {
                 if (kvp.Value.L is not null)
diff --git a/src/Clients/Goa.Clients.Bedrock.Conversation.Dynamo/DynamoConversationStoreConfiguration.cs b/src/Clients/Goa.Clients.Bedrock.Conversation.Dynamo/DynamoConversationStoreConfiguration.cs
index 54092c39..b338c978 100644
--- a/src/Clients/Goa.Clients.Bedrock.Conversation.Dynamo/DynamoConversationStoreConfiguration.cs
+++ b/src/Clients/Goa.Clients.Bedrock.Conversation.Dynamo/DynamoConversationStoreConfiguration.cs
@@ -3,7 +3,7 @@ namespace Goa.Clients.Bedrock.Conversation.Dynamo;
 /// <summary>
 /// Configuration for the DynamoDB-backed conversation store.
 /// </summary>
-public class DynamoConversationStoreConfiguration
+public sealed class DynamoConversationStoreConfiguration
 {
     /// <summary>
     /// The name of the DynamoDB table to store conversations.
diff --git a/src/Clients/Goa.Clients.Bedrock.Conversation.Dynamo/Internal/ContentBlockSerializer.cs b/src/Clients/Goa.Clients.Bedrock.Conversation.Dynamo/Internal/ContentBlockSerializer.cs
index 95a772d9..0c9d5150 100644
--- a/src/Clients/Goa.Clients.Bedrock.Conversation.Dynamo/Internal/ContentBlockSerializer.cs
+++ b/src/Clients/Goa.Clients.Bedrock.Conversation.Dynamo/Internal/ContentBlockSerializer.cs
@@ -26,7 +26,7 @@ public static ErrorOr<AttributeValue> Serialize(ContentBlock block)
     {
         if (block.Text is not null)
         {
-            return AttributeValue.FromMap(new Dictionary<string, AttributeValue>
+            return AttributeValue.FromMap(new Dictionary<string, AttributeValue>(2)
             {
                 [TypeAttribute] = TextType,
                 ["text"] = block.Text
@@ -39,7 +39,7 @@ public static ErrorOr<AttributeValue> Serialize(ContentBlock block)
             if (validation.IsError)
                 return validation.Errors;
 
-            var imageMap = new Dictionary<string, AttributeValue>
+            var imageMap = new Dictionary<string, AttributeValue>(4)
             {
                 [TypeAttribute] = ImageType,
                 ["format"] = block.Image.Format
@@ -61,7 +61,7 @@ public static ErrorOr<AttributeValue> Serialize(ContentBlock block)
             if (validation.IsError)
                 return validation.Errors;
 
-            var docMap = new Dictionary<string, AttributeValue>
+            var docMap = new Dictionary<string, AttributeValue>(5)
             {
                 [TypeAttribute] = DocumentType,
                 ["format"] = block.Document.Format,
@@ -80,7 +80,7 @@ public static ErrorOr<AttributeValue> Serialize(ContentBlock block)
 
         if (block.ToolUse is not null)
         {
-            var toolUseMap = new Dictionary<string, AttributeValue>
+            var toolUseMap = new Dictionary<string, AttributeValue>(4)
             {
                 [TypeAttribute] = ToolUseType,
                 ["toolUseId"] = block.ToolUse.ToolUseId,
@@ -102,7 +102,7 @@ public static ErrorOr<AttributeValue> Serialize(ContentBlock block)
                 contentList.Add(serialized.Value);
             }
 
-            var toolResultMap = new Dictionary<string, AttributeValue>
+            var toolResultMap = new Dictionary<string, AttributeValue>(4)
             {
                 [TypeAttribute] = ToolResultType,
                 ["toolUseId"] = block.ToolResult.ToolUseId,
diff --git a/src/Clients/Goa.Clients.Bedrock.Conversation/Chat/ChatSession.cs b/src/Clients/Goa.Clients.Bedrock.Conversation/Chat/ChatSession.cs
index bb870330..d31fa971 100644
--- a/src/Clients/Goa.Clients.Bedrock.Conversation/Chat/ChatSession.cs
+++ b/src/Clients/Goa.Clients.Bedrock.Conversation/Chat/ChatSession.cs
@@ -88,7 +88,7 @@ public async Task<ErrorOr<ChatResponse>> SendAsync(IEnumerable<ContentBlock> con
         var userMessage = new Message
         {
             Role = ConversationRole.User,
-            Content = content.ToList()
+            Content = new List<ContentBlock>(content)
         };
 
         // Clean message content (extract XML tags)
@@ -163,24 +163,32 @@ public async Task<ErrorOr<ChatResponse>> SendAsync(IEnumerable<ContentBlock> con
                 }
 
                 // Execute tools
-                var toolUseBlocks = assistantMessage.Content
-                    .Where(c => c.ToolUse != null)
-                    .Select(c => c.ToolUse!)
-                    .ToList();
-
                 var toolResults = new List<ContentBlock>();
-                foreach (var toolUse in toolUseBlocks)
+                foreach (var block in assistantMessage.Content)
                 {
+                    var toolUse = block.ToolUse;
+                    if (toolUse is null) continue;
+
                     var toolResult = await _toolAdapter.ExecuteToolAsync(toolUse, ct).ConfigureAwait(false);
                     toolResults.Add(new ContentBlock { ToolResult = toolResult });
 
+                    string resultText = string.Empty;
+                    foreach (var resultContent in toolResult.Content)
+                    {
+                        if (resultContent.Text is not null)
+                        {
+                            resultText = resultContent.Text;
+                            break;
+                        }
+                    }
+
                     // Track tool execution
                     toolExecutions.Add(new ToolExecution
                     {
                         ToolName = toolUse.Name,
                         ToolUseId = toolUse.ToolUseId,
                         Input = JsonDocument.Parse(toolUse.Input.GetRawText()),
-                        Result = toolResult.Content.FirstOrDefault()?.Text ?? string.Empty,
+                        Result = resultText,
                         Success = toolResult.Status == "success"
                     });
                 }
@@ -218,10 +226,15 @@ public async Task<ErrorOr<ChatResponse>> SendAsync(IEnumerable<ContentBlock> con
                 var (cleanedFinalMessage, finalExtractedTags) = CleanMessageContent(finalMessage);
 
                 // Extract cleaned text content
-                var cleanedText = cleanedFinalMessage.Content
-                    .Where(c => c.Text != null)
-                    .Select(c => c.Text!)
-                    .FirstOrDefault() ?? string.Empty;
+                var cleanedText = string.Empty;
+                foreach (var block in cleanedFinalMessage.Content)
+                {
+                    if (block.Text is not null)
+                    {
+                        cleanedText = block.Text;
+                        break;
+                    }
+                }
 
                 // Detect thinking-only response: tags were extracted but no real text remains.
                 // Note: CleanMessageContent preserves original content when all text blocks are
@@ -305,13 +318,17 @@ public async Task<ErrorOr<ChatResponse>> SendAsync(IEnumerable<ContentBlock> con
     /// <inheritdoc />
     public Task<ErrorOr<IReadOnlyList<ChatMessage>>> GetHistoryAsync(CancellationToken ct = default)
     {
-        var history = _messages.Select((m, index) => new ChatMessage
+        var history = new List<ChatMessage>(_messages.Count);
+        foreach (var m in _messages)
         {
-            Role = m.Role,
-            Content = m.Content,
-            Timestamp = DateTimeOffset.UtcNow, // In-memory messages don't have timestamps
-            TokenUsage = null
-        }).ToList();
+            history.Add(new ChatMessage
+            {
+                Role = m.Role,
+                Content = m.Content,
+                Timestamp = DateTimeOffset.UtcNow, // In-memory messages don't have timestamps
+                TokenUsage = null
+            });
+        }
 
         return Task.FromResult<ErrorOr<IReadOnlyList<ChatMessage>>>(history);
     }
@@ -416,14 +433,16 @@ private static (Message CleanedMessage, IReadOnlyDictionary<string, IReadOnlyLis
             }
         }
 
-        var result = allTags.ToDictionary(
-            kvp => kvp.Key,
-            kvp => (IReadOnlyList<string>)kvp.Value);
+        var result = new Dictionary<string, IReadOnlyList<string>>(allTags.Count);
+        foreach (var kvp in allTags)
+        {
+            result[kvp.Key] = kvp.Value;
+        }
 
         if (cleanedContent.Count == 0 && message.Content.Count > 0)
         {
             // Tag extraction emptied all content - preserve original to avoid empty messages
-            return (new Message { Role = message.Role, Content = message.Content.ToList() }, result);
+            return (new Message { Role = message.Role, Content = new List<ContentBlock>(message.Content) }, result);
         }
 
         return (new Message { Role = message.Role, Content = cleanedContent }, result);
@@ -452,7 +471,10 @@ private ConverseRequest BuildConverseRequest(IReadOnlyList<Tool>? bedrockTools)
 
         if (_options.StopSequences is { Count: > 0 })
         {
-            builder.WithStopSequences(_options.StopSequences.ToArray());
+            if (_options.StopSequences is string[] arr)
+                builder.WithStopSequences(arr);
+            else
+                builder.WithStopSequences(_options.StopSequences.ToArray());
         }
 
         if (_options.ServiceTier.HasValue)
@@ -471,7 +493,7 @@ private ConverseRequest BuildConverseRequest(IReadOnlyList<Tool>? bedrockTools)
         // Add tools if any are registered
         if (bedrockTools is { Count: > 0 })
         {
-            request.ToolConfig = new ToolConfiguration { Tools = bedrockTools.ToList() };
+            request.ToolConfig = new ToolConfiguration { Tools = new List<Tool>(bedrockTools) };
         }
 
         if (_options.OutputConfig is not null)
diff --git a/src/Clients/Goa.Clients.Bedrock.Conversation/Entities/Conversation.cs b/src/Clients/Goa.Clients.Bedrock.Conversation/Entities/Conversation.cs
index df1be89c..ace422fd 100644
--- a/src/Clients/Goa.Clients.Bedrock.Conversation/Entities/Conversation.cs
+++ b/src/Clients/Goa.Clients.Bedrock.Conversation/Entities/Conversation.cs
@@ -5,7 +5,7 @@ namespace Goa.Clients.Bedrock.Conversation.Entities;
 /// <summary>
 /// Represents a conversation with a Bedrock model.
 /// </summary>
-public class Conversation
+public sealed class Conversation
 {
     /// <summary>
     /// The unique identifier for the conversation.
diff --git a/src/Clients/Goa.Clients.Bedrock.Conversation/Entities/ConversationListResult.cs b/src/Clients/Goa.Clients.Bedrock.Conversation/Entities/ConversationListResult.cs
index fc4fea2f..be86902e 100644
--- a/src/Clients/Goa.Clients.Bedrock.Conversation/Entities/ConversationListResult.cs
+++ b/src/Clients/Goa.Clients.Bedrock.Conversation/Entities/ConversationListResult.cs
@@ -3,7 +3,7 @@ namespace Goa.Clients.Bedrock.Conversation.Entities;
 /// <summary>
 /// Represents the result of listing conversations.
 /// </summary>
-public class ConversationListResult
+public sealed class ConversationListResult
 {
     /// <summary>
     /// The list of conversations.
diff --git a/src/Clients/Goa.Clients.Bedrock.Conversation/Entities/ConversationMessage.cs b/src/Clients/Goa.Clients.Bedrock.Conversation/Entities/ConversationMessage.cs
index 98a61e7a..12dfa869 100644
--- a/src/Clients/Goa.Clients.Bedrock.Conversation/Entities/ConversationMessage.cs
+++ b/src/Clients/Goa.Clients.Bedrock.Conversation/Entities/ConversationMessage.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Bedrock.Conversation.Entities;
 /// <summary>
 /// Represents a message within a conversation.
 /// </summary>
-public class ConversationMessage
+public sealed class ConversationMessage
 {
     /// <summary>
     /// The unique identifier for the message.
diff --git a/src/Clients/Goa.Clients.Bedrock.Conversation/Entities/ConversationMetadata.cs b/src/Clients/Goa.Clients.Bedrock.Conversation/Entities/ConversationMetadata.cs
index 8fedd863..c1e5b87d 100644
--- a/src/Clients/Goa.Clients.Bedrock.Conversation/Entities/ConversationMetadata.cs
+++ b/src/Clients/Goa.Clients.Bedrock.Conversation/Entities/ConversationMetadata.cs
@@ -3,7 +3,7 @@ namespace Goa.Clients.Bedrock.Conversation.Entities;
 /// <summary>
 /// Metadata associated with a conversation.
 /// </summary>
-public class ConversationMetadata
+public sealed class ConversationMetadata
 {
     /// <summary>
     /// The title of the conversation.
diff --git a/src/Clients/Goa.Clients.Bedrock.Conversation/Entities/ConversationWithMessages.cs b/src/Clients/Goa.Clients.Bedrock.Conversation/Entities/ConversationWithMessages.cs
index c62116c3..8ae8e559 100644
--- a/src/Clients/Goa.Clients.Bedrock.Conversation/Entities/ConversationWithMessages.cs
+++ b/src/Clients/Goa.Clients.Bedrock.Conversation/Entities/ConversationWithMessages.cs
@@ -3,7 +3,7 @@ namespace Goa.Clients.Bedrock.Conversation.Entities;
 /// <summary>
 /// Represents a conversation with its associated messages.
 /// </summary>
-public class ConversationWithMessages
+public sealed class ConversationWithMessages
 {
     /// <summary>
     /// The conversation.
diff --git a/src/Clients/Goa.Clients.Bedrock.Conversation/Internal/XmlTagParser.cs b/src/Clients/Goa.Clients.Bedrock.Conversation/Internal/XmlTagParser.cs
index 94e5e198..226c90e3 100644
--- a/src/Clients/Goa.Clients.Bedrock.Conversation/Internal/XmlTagParser.cs
+++ b/src/Clients/Goa.Clients.Bedrock.Conversation/Internal/XmlTagParser.cs
@@ -43,7 +43,7 @@ public static (string CleanedText, IReadOnlyDictionary<string, IReadOnlyList<str
         var cleanedText = XmlTagRegex().Replace(text, string.Empty).Trim();
 
         // Convert to read-only dictionary
-        var result = new Dictionary<string, IReadOnlyList<string>>();
+        var result = new Dictionary<string, IReadOnlyList<string>>(tags.Count);
         foreach (var kvp in tags)
         {
             result[kvp.Key] = kvp.Value;
diff --git a/src/Clients/Goa.Clients.Bedrock/BedrockServiceClient.cs b/src/Clients/Goa.Clients.Bedrock/BedrockServiceClient.cs
index 78870286..7a55300a 100644
--- a/src/Clients/Goa.Clients.Bedrock/BedrockServiceClient.cs
+++ b/src/Clients/Goa.Clients.Bedrock/BedrockServiceClient.cs
@@ -17,7 +17,7 @@ namespace Goa.Clients.Bedrock;
 /// High-performance Bedrock service client that implements IBedrockClient using AWS service client infrastructure.
 /// Provides strongly-typed Bedrock operations with built-in error handling, logging, and AWS authentication.
 /// </summary>
-public class BedrockServiceClient : JsonAwsServiceClient<BedrockServiceClientConfiguration>, IBedrockClient
+public sealed class BedrockServiceClient : JsonAwsServiceClient<BedrockServiceClientConfiguration>, IBedrockClient
 {
     /// <summary>
     /// Initializes a new instance of the BedrockServiceClient class.
@@ -111,7 +111,7 @@ public async Task<ErrorOr<InvokeModelResponse>> InvokeModelAsync(InvokeModelRequ
         return new InvokeModelResponse
         {
             Body = response.Value ?? string.Empty,
-            ContentType = response.Headers?.ContentType
+            ContentType = response.ContentType
         };
     }
 
diff --git a/src/Clients/Goa.Clients.Bedrock/BedrockServiceClientConfiguration.cs b/src/Clients/Goa.Clients.Bedrock/BedrockServiceClientConfiguration.cs
index 23f82172..b7bf196f 100644
--- a/src/Clients/Goa.Clients.Bedrock/BedrockServiceClientConfiguration.cs
+++ b/src/Clients/Goa.Clients.Bedrock/BedrockServiceClientConfiguration.cs
@@ -5,7 +5,7 @@ namespace Goa.Clients.Bedrock;
 /// <summary>
 /// Configuration class for Bedrock Runtime service providing Bedrock-specific settings.
 /// </summary>
-public class BedrockServiceClientConfiguration : AwsServiceConfiguration
+public sealed class BedrockServiceClientConfiguration : AwsServiceConfiguration
 {
     /// <summary>
     /// Initializes a new instance of the BedrockServiceClientConfiguration class.
diff --git a/src/Clients/Goa.Clients.Bedrock/Errors/ErrorExtensions.cs b/src/Clients/Goa.Clients.Bedrock/Errors/ErrorExtensions.cs
index 2ed6c7cb..7fdb32b2 100644
--- a/src/Clients/Goa.Clients.Bedrock/Errors/ErrorExtensions.cs
+++ b/src/Clients/Goa.Clients.Bedrock/Errors/ErrorExtensions.cs
@@ -16,7 +16,12 @@ public static class ErrorExtensions
     public static bool IsBedrockError<T>(this ErrorOr<T> errorOr)
     {
         if (!errorOr.IsError) return false;
-        return errorOr.Errors.Any(e => e.Code.StartsWith("Goa.Bedrock.", StringComparison.Ordinal));
+        foreach (var e in errorOr.Errors)
+        {
+            if (e.Code.StartsWith("Goa.Bedrock.", StringComparison.Ordinal))
+                return true;
+        }
+        return false;
     }
 
     /// <summary>
@@ -28,9 +33,13 @@ public static bool IsBedrockError<T>(this ErrorOr<T> errorOr)
     public static bool IsBedrockThrottlingError<T>(this ErrorOr<T> errorOr)
     {
         if (!errorOr.IsError) return false;
-        return errorOr.Errors.Any(e =>
-            e.Code == BedrockErrorCodes.ThrottlingException ||
-            e.Code == BedrockErrorCodes.ServiceQuotaExceededException);
+        foreach (var e in errorOr.Errors)
+        {
+            if (e.Code == BedrockErrorCodes.ThrottlingException ||
+                e.Code == BedrockErrorCodes.ServiceQuotaExceededException)
+                return true;
+        }
+        return false;
     }
 
     /// <summary>
@@ -42,9 +51,13 @@ public static bool IsBedrockThrottlingError<T>(this ErrorOr<T> errorOr)
     public static bool IsBedrockValidationError<T>(this ErrorOr<T> errorOr)
     {
         if (!errorOr.IsError) return false;
-        return errorOr.Errors.Any(e =>
-            e.Code == BedrockErrorCodes.ValidationException ||
-            e.Type == ErrorType.Validation);
+        foreach (var e in errorOr.Errors)
+        {
+            if (e.Code == BedrockErrorCodes.ValidationException ||
+                e.Type == ErrorType.Validation)
+                return true;
+        }
+        return false;
     }
 
     /// <summary>
@@ -56,10 +69,14 @@ public static bool IsBedrockValidationError<T>(this ErrorOr<T> errorOr)
     public static bool IsBedrockModelError<T>(this ErrorOr<T> errorOr)
     {
         if (!errorOr.IsError) return false;
-        return errorOr.Errors.Any(e =>
-            e.Code == BedrockErrorCodes.ModelErrorException ||
-            e.Code == BedrockErrorCodes.ModelNotReadyException ||
-            e.Code == BedrockErrorCodes.ModelTimeoutException);
+        foreach (var e in errorOr.Errors)
+        {
+            if (e.Code == BedrockErrorCodes.ModelErrorException ||
+                e.Code == BedrockErrorCodes.ModelNotReadyException ||
+                e.Code == BedrockErrorCodes.ModelTimeoutException)
+                return true;
+        }
+        return false;
     }
 
     /// <summary>
@@ -72,7 +89,13 @@ public static bool IsBedrockModelError<T>(this ErrorOr<T> errorOr)
     public static bool IsBedrockRetryableError<T>(this ErrorOr<T> errorOr)
     {
         if (!errorOr.IsError) return false;
-        return errorOr.IsBedrockThrottlingError() ||
-               errorOr.Errors.Any(e => e.Code == BedrockErrorCodes.ModelTimeoutException);
+        foreach (var e in errorOr.Errors)
+        {
+            if (e.Code == BedrockErrorCodes.ThrottlingException ||
+                e.Code == BedrockErrorCodes.ServiceQuotaExceededException ||
+                e.Code == BedrockErrorCodes.ModelTimeoutException)
+                return true;
+        }
+        return false;
     }
 }
diff --git a/src/Clients/Goa.Clients.Bedrock/Mcp/McpToolDefinition.cs b/src/Clients/Goa.Clients.Bedrock/Mcp/McpToolDefinition.cs
index cdb2403e..1295f1e7 100644
--- a/src/Clients/Goa.Clients.Bedrock/Mcp/McpToolDefinition.cs
+++ b/src/Clients/Goa.Clients.Bedrock/Mcp/McpToolDefinition.cs
@@ -5,7 +5,7 @@ namespace Goa.Clients.Bedrock.Mcp;
 /// <summary>
 /// Represents an MCP tool definition that can be converted to Bedrock format.
 /// </summary>
-public class McpToolDefinition
+public sealed class McpToolDefinition
 {
     /// <summary>
     /// The name of the tool.
diff --git a/src/Clients/Goa.Clients.Bedrock/Models/CachePoint.cs b/src/Clients/Goa.Clients.Bedrock/Models/CachePoint.cs
index 1eaa9a45..3ff9d42e 100644
--- a/src/Clients/Goa.Clients.Bedrock/Models/CachePoint.cs
+++ b/src/Clients/Goa.Clients.Bedrock/Models/CachePoint.cs
@@ -3,7 +3,7 @@ namespace Goa.Clients.Bedrock.Models;
 /// <summary>
 /// A cache checkpoint for prompt caching in Bedrock.
 /// </summary>
-public class CachePoint
+public sealed class CachePoint
 {
     /// <summary>
     /// The type of cache point. Currently only "default" is supported.
diff --git a/src/Clients/Goa.Clients.Bedrock/Models/ContentBlock.cs b/src/Clients/Goa.Clients.Bedrock/Models/ContentBlock.cs
index 697148d2..9142af95 100644
--- a/src/Clients/Goa.Clients.Bedrock/Models/ContentBlock.cs
+++ b/src/Clients/Goa.Clients.Bedrock/Models/ContentBlock.cs
@@ -5,7 +5,7 @@ namespace Goa.Clients.Bedrock.Models;
 /// <summary>
 /// A block of content in a message. Only one type of content can be set per block.
 /// </summary>
-public class ContentBlock
+public sealed class ContentBlock
 {
     /// <summary>
     /// Text content.
diff --git a/src/Clients/Goa.Clients.Bedrock/Models/ConverseMetrics.cs b/src/Clients/Goa.Clients.Bedrock/Models/ConverseMetrics.cs
index dcefe130..e41b2833 100644
--- a/src/Clients/Goa.Clients.Bedrock/Models/ConverseMetrics.cs
+++ b/src/Clients/Goa.Clients.Bedrock/Models/ConverseMetrics.cs
@@ -3,7 +3,7 @@ namespace Goa.Clients.Bedrock.Models;
 /// <summary>
 /// Performance metrics for a conversation request.
 /// </summary>
-public class ConverseMetrics
+public sealed class ConverseMetrics
 {
     /// <summary>
     /// The latency of the request in milliseconds.
diff --git a/src/Clients/Goa.Clients.Bedrock/Models/DocumentBlock.cs b/src/Clients/Goa.Clients.Bedrock/Models/DocumentBlock.cs
index 9c7fec43..f78f1c80 100644
--- a/src/Clients/Goa.Clients.Bedrock/Models/DocumentBlock.cs
+++ b/src/Clients/Goa.Clients.Bedrock/Models/DocumentBlock.cs
@@ -3,7 +3,7 @@ namespace Goa.Clients.Bedrock.Models;
 /// <summary>
 /// A document block in a message.
 /// </summary>
-public class DocumentBlock
+public sealed class DocumentBlock
 {
     /// <summary>
     /// The format of the document (e.g., "pdf", "csv", "doc", "docx", "xls", "xlsx", "html", "txt", "md").
@@ -24,7 +24,7 @@ public class DocumentBlock
 /// <summary>
 /// The source of a document.
 /// </summary>
-public class DocumentSource
+public sealed class DocumentSource
 {
     /// <summary>
     /// Base64-encoded document bytes.
diff --git a/src/Clients/Goa.Clients.Bedrock/Models/GuardrailConfiguration.cs b/src/Clients/Goa.Clients.Bedrock/Models/GuardrailConfiguration.cs
index 11764a2d..95c615d4 100644
--- a/src/Clients/Goa.Clients.Bedrock/Models/GuardrailConfiguration.cs
+++ b/src/Clients/Goa.Clients.Bedrock/Models/GuardrailConfiguration.cs
@@ -3,7 +3,7 @@ namespace Goa.Clients.Bedrock.Models;
 /// <summary>
 /// Configuration for guardrails to apply to the conversation.
 /// </summary>
-public class GuardrailConfiguration
+public sealed class GuardrailConfiguration
 {
     /// <summary>
     /// The identifier of the guardrail to apply.
diff --git a/src/Clients/Goa.Clients.Bedrock/Models/ImageBlock.cs b/src/Clients/Goa.Clients.Bedrock/Models/ImageBlock.cs
index e05b6adb..38bce5dd 100644
--- a/src/Clients/Goa.Clients.Bedrock/Models/ImageBlock.cs
+++ b/src/Clients/Goa.Clients.Bedrock/Models/ImageBlock.cs
@@ -3,7 +3,7 @@ namespace Goa.Clients.Bedrock.Models;
 /// <summary>
 /// An image block in a message.
 /// </summary>
-public class ImageBlock
+public sealed class ImageBlock
 {
     /// <summary>
     /// The format of the image (e.g., "png", "jpeg", "gif", "webp").
@@ -19,7 +19,7 @@ public class ImageBlock
 /// <summary>
 /// The source of an image.
 /// </summary>
-public class ImageSource
+public sealed class ImageSource
 {
     /// <summary>
     /// Base64-encoded image bytes.
@@ -35,7 +35,7 @@ public class ImageSource
 /// <summary>
 /// S3 location reference for content.
 /// </summary>
-public class S3Location
+public sealed class S3Location
 {
     /// <summary>
     /// The S3 URI of the content.
diff --git a/src/Clients/Goa.Clients.Bedrock/Models/InferenceConfiguration.cs b/src/Clients/Goa.Clients.Bedrock/Models/InferenceConfiguration.cs
index bb53a1eb..2c5f1b96 100644
--- a/src/Clients/Goa.Clients.Bedrock/Models/InferenceConfiguration.cs
+++ b/src/Clients/Goa.Clients.Bedrock/Models/InferenceConfiguration.cs
@@ -3,7 +3,7 @@ namespace Goa.Clients.Bedrock.Models;
 /// <summary>
 /// Configuration for model inference parameters.
 /// </summary>
-public class InferenceConfiguration
+public sealed class InferenceConfiguration
 {
     /// <summary>
     /// The maximum number of tokens to generate in the response.
diff --git a/src/Clients/Goa.Clients.Bedrock/Models/Message.cs b/src/Clients/Goa.Clients.Bedrock/Models/Message.cs
index dc7106bb..b0e0a4c9 100644
--- a/src/Clients/Goa.Clients.Bedrock/Models/Message.cs
+++ b/src/Clients/Goa.Clients.Bedrock/Models/Message.cs
@@ -5,7 +5,7 @@ namespace Goa.Clients.Bedrock.Models;
 /// <summary>
 /// A message in a conversation with a model.
 /// </summary>
-public class Message
+public sealed class Message
 {
     /// <summary>
     /// The role of the entity sending the message.
diff --git a/src/Clients/Goa.Clients.Bedrock/Models/OutputConfig.cs b/src/Clients/Goa.Clients.Bedrock/Models/OutputConfig.cs
index a9931720..ac771c0f 100644
--- a/src/Clients/Goa.Clients.Bedrock/Models/OutputConfig.cs
+++ b/src/Clients/Goa.Clients.Bedrock/Models/OutputConfig.cs
@@ -3,7 +3,7 @@ namespace Goa.Clients.Bedrock.Models;
 /// <summary>
 /// Configuration for the output format of a Converse request.
 /// </summary>
-public class OutputConfig
+public sealed class OutputConfig
 {
     /// <summary>
     /// The text format configuration for structured output.
@@ -14,7 +14,7 @@ public class OutputConfig
 /// <summary>
 /// The text output format specification. Set Type to "json_schema" and provide Structure for JSON schema output.
 /// </summary>
-public class OutputFormat
+public sealed class OutputFormat
 {
     /// <summary>
     /// The type of output format. Use "json_schema" for structured output.
@@ -30,7 +30,7 @@ public class OutputFormat
 /// <summary>
 /// The structure definition for a structured output format. This is a union type - only one member should be set.
 /// </summary>
-public class OutputFormatStructure
+public sealed class OutputFormatStructure
 {
     /// <summary>
     /// The JSON schema definition for structured output.
@@ -41,7 +41,7 @@ public class OutputFormatStructure
 /// <summary>
 /// Defines a JSON schema that the model's output must adhere to.
 /// </summary>
-public class JsonSchemaDefinition
+public sealed class JsonSchemaDefinition
 {
     /// <summary>
     /// The JSON schema as a JSON-stringified string. The Converse API requires this as a string, not a JSON object.
diff --git a/src/Clients/Goa.Clients.Bedrock/Models/PerformanceConfiguration.cs b/src/Clients/Goa.Clients.Bedrock/Models/PerformanceConfiguration.cs
index 381bddb1..441f3ea1 100644
--- a/src/Clients/Goa.Clients.Bedrock/Models/PerformanceConfiguration.cs
+++ b/src/Clients/Goa.Clients.Bedrock/Models/PerformanceConfiguration.cs
@@ -5,7 +5,7 @@ namespace Goa.Clients.Bedrock.Models;
 /// <summary>
 /// Configuration for performance optimization.
 /// </summary>
-public class PerformanceConfiguration
+public sealed class PerformanceConfiguration
 {
     /// <summary>
     /// The latency mode for model inference.
diff --git a/src/Clients/Goa.Clients.Bedrock/Models/TokenUsage.cs b/src/Clients/Goa.Clients.Bedrock/Models/TokenUsage.cs
index 322a4899..6d574156 100644
--- a/src/Clients/Goa.Clients.Bedrock/Models/TokenUsage.cs
+++ b/src/Clients/Goa.Clients.Bedrock/Models/TokenUsage.cs
@@ -3,7 +3,7 @@ namespace Goa.Clients.Bedrock.Models;
 /// <summary>
 /// Token usage information for a conversation request.
 /// </summary>
-public class TokenUsage
+public sealed class TokenUsage
 {
     /// <summary>
     /// The number of tokens in the input.
diff --git a/src/Clients/Goa.Clients.Bedrock/Models/Tool.cs b/src/Clients/Goa.Clients.Bedrock/Models/Tool.cs
index df936fd7..9d0fe783 100644
--- a/src/Clients/Goa.Clients.Bedrock/Models/Tool.cs
+++ b/src/Clients/Goa.Clients.Bedrock/Models/Tool.cs
@@ -5,7 +5,7 @@ namespace Goa.Clients.Bedrock.Models;
 /// <summary>
 /// A tool definition that the model can use.
 /// </summary>
-public class Tool
+public sealed class Tool
 {
     /// <summary>
     /// The specification of the tool.
@@ -16,7 +16,7 @@ public class Tool
 /// <summary>
 /// The specification of a tool including its name, description, and input schema.
 /// </summary>
-public class ToolSpec
+public sealed class ToolSpec
 {
     /// <summary>
     /// The name of the tool.
@@ -42,7 +42,7 @@ public class ToolSpec
 /// <summary>
 /// The input schema for a tool. This is a union type - only the Json member should be set.
 /// </summary>
-public class ToolInputSchema
+public sealed class ToolInputSchema
 {
     /// <summary>
     /// The JSON schema for the tool's input parameters.
diff --git a/src/Clients/Goa.Clients.Bedrock/Models/ToolConfiguration.cs b/src/Clients/Goa.Clients.Bedrock/Models/ToolConfiguration.cs
index c6f8a696..56b479fb 100644
--- a/src/Clients/Goa.Clients.Bedrock/Models/ToolConfiguration.cs
+++ b/src/Clients/Goa.Clients.Bedrock/Models/ToolConfiguration.cs
@@ -3,7 +3,7 @@ namespace Goa.Clients.Bedrock.Models;
 /// <summary>
 /// Configuration for tool use in a conversation.
 /// </summary>
-public class ToolConfiguration
+public sealed class ToolConfiguration
 {
     /// <summary>
     /// The list of tools available to the model.
@@ -19,7 +19,7 @@ public class ToolConfiguration
 /// <summary>
 /// Configuration for how the model should choose which tool to use.
 /// </summary>
-public class ToolChoice
+public sealed class ToolChoice
 {
     /// <summary>
     /// If set, the model will automatically decide whether to use a tool.
@@ -40,17 +40,17 @@ public class ToolChoice
 /// <summary>
 /// Marker class indicating automatic tool choice.
 /// </summary>
-public class AutoToolChoice { }
+public sealed class AutoToolChoice { }
 
 /// <summary>
 /// Marker class indicating any tool can be chosen.
 /// </summary>
-public class AnyToolChoice { }
+public sealed class AnyToolChoice { }
 
 /// <summary>
 /// Configuration to force the model to use a specific tool.
 /// </summary>
-public class SpecificToolChoice
+public sealed class SpecificToolChoice
 {
     /// <summary>
     /// The name of the tool the model must use.
diff --git a/src/Clients/Goa.Clients.Bedrock/Models/ToolResultBlock.cs b/src/Clients/Goa.Clients.Bedrock/Models/ToolResultBlock.cs
index 16680146..d9985811 100644
--- a/src/Clients/Goa.Clients.Bedrock/Models/ToolResultBlock.cs
+++ b/src/Clients/Goa.Clients.Bedrock/Models/ToolResultBlock.cs
@@ -3,7 +3,7 @@ namespace Goa.Clients.Bedrock.Models;
 /// <summary>
 /// A tool result block containing the response from a tool invocation.
 /// </summary>
-public class ToolResultBlock
+public sealed class ToolResultBlock
 {
     /// <summary>
     /// The identifier of the tool use request this is a response to.
diff --git a/src/Clients/Goa.Clients.Bedrock/Models/ToolUseBlock.cs b/src/Clients/Goa.Clients.Bedrock/Models/ToolUseBlock.cs
index f780a7f4..5dffedf5 100644
--- a/src/Clients/Goa.Clients.Bedrock/Models/ToolUseBlock.cs
+++ b/src/Clients/Goa.Clients.Bedrock/Models/ToolUseBlock.cs
@@ -5,7 +5,7 @@ namespace Goa.Clients.Bedrock.Models;
 /// <summary>
 /// A tool use block indicating the model wants to invoke a tool.
 /// </summary>
-public class ToolUseBlock
+public sealed class ToolUseBlock
 {
     /// <summary>
     /// A unique identifier for this tool use request.
diff --git a/src/Clients/Goa.Clients.Bedrock/Operations/Converse/ConverseBuilder.cs b/src/Clients/Goa.Clients.Bedrock/Operations/Converse/ConverseBuilder.cs
index ec3bf008..0a507582 100644
--- a/src/Clients/Goa.Clients.Bedrock/Operations/Converse/ConverseBuilder.cs
+++ b/src/Clients/Goa.Clients.Bedrock/Operations/Converse/ConverseBuilder.cs
@@ -8,7 +8,7 @@ namespace Goa.Clients.Bedrock.Operations.Converse;
 /// Fluent builder for constructing Bedrock Converse requests.
 /// </summary>
 /// <param name="modelId">The identifier of the model to use.</param>
-public class ConverseBuilder(string modelId)
+public sealed class ConverseBuilder(string modelId)
 {
     private readonly ConverseRequest _request = new()
     {
diff --git a/src/Clients/Goa.Clients.Bedrock/Operations/Converse/ConverseRequest.cs b/src/Clients/Goa.Clients.Bedrock/Operations/Converse/ConverseRequest.cs
index a4215804..66edd8a1 100644
--- a/src/Clients/Goa.Clients.Bedrock/Operations/Converse/ConverseRequest.cs
+++ b/src/Clients/Goa.Clients.Bedrock/Operations/Converse/ConverseRequest.cs
@@ -7,7 +7,7 @@ namespace Goa.Clients.Bedrock.Operations.Converse;
 /// <summary>
 /// Request for the Bedrock Converse API.
 /// </summary>
-public class ConverseRequest
+public sealed class ConverseRequest
 {
     /// <summary>
     /// The identifier of the model to use.
@@ -73,7 +73,7 @@ public class ConverseRequest
 /// <summary>
 /// A system content block for providing context.
 /// </summary>
-public class SystemContentBlock
+public sealed class SystemContentBlock
 {
     /// <summary>
     /// Text content for the system prompt.
@@ -91,7 +91,7 @@ public class SystemContentBlock
 /// <summary>
 /// Request metadata including service tier.
 /// </summary>
-public class RequestMetadata
+public sealed class RequestMetadata
 {
     /// <summary>
     /// The service tier for request processing.
diff --git a/src/Clients/Goa.Clients.Bedrock/Operations/Converse/ConverseResponse.cs b/src/Clients/Goa.Clients.Bedrock/Operations/Converse/ConverseResponse.cs
index 9d445b90..367f14f6 100644
--- a/src/Clients/Goa.Clients.Bedrock/Operations/Converse/ConverseResponse.cs
+++ b/src/Clients/Goa.Clients.Bedrock/Operations/Converse/ConverseResponse.cs
@@ -7,7 +7,7 @@ namespace Goa.Clients.Bedrock.Operations.Converse;
 /// <summary>
 /// Response from the Bedrock Converse API.
 /// </summary>
-public class ConverseResponse
+public sealed class ConverseResponse
 {
     /// <summary>
     /// The output from the model.
@@ -37,7 +37,7 @@ public class ConverseResponse
 /// <summary>
 /// The output from a Converse API call.
 /// </summary>
-public class ConverseOutput
+public sealed class ConverseOutput
 {
     /// <summary>
     /// The message generated by the model.
diff --git a/src/Clients/Goa.Clients.Bedrock/Serialization/ConversationRoleConverter.cs b/src/Clients/Goa.Clients.Bedrock/Serialization/ConversationRoleConverter.cs
index e11587ad..38c2d593 100644
--- a/src/Clients/Goa.Clients.Bedrock/Serialization/ConversationRoleConverter.cs
+++ b/src/Clients/Goa.Clients.Bedrock/Serialization/ConversationRoleConverter.cs
@@ -1,6 +1,7 @@
 using System.Text.Json;
 using System.Text.Json.Serialization;
 using Goa.Clients.Bedrock.Enums;
+using Goa.Clients.Core;
 
 namespace Goa.Clients.Bedrock.Serialization;
 
@@ -18,7 +19,7 @@ public override ConversationRole Read(ref Utf8JsonReader reader, Type typeToConv
         {
             "user" => ConversationRole.User,
             "assistant" => ConversationRole.Assistant,
-            _ => throw new JsonException($"Unknown ConversationRole: {value}")
+            _ => Throw.JsonException<ConversationRole>($"Unknown ConversationRole: {value}")
         };
     }
 
@@ -29,7 +30,7 @@ public override void Write(Utf8JsonWriter writer, ConversationRole value, JsonSe
         {
             ConversationRole.User => "user",
             ConversationRole.Assistant => "assistant",
-            _ => throw new JsonException($"Unknown ConversationRole: {value}")
+            _ => Throw.JsonException<string>($"Unknown ConversationRole: {value}")
         };
         writer.WriteStringValue(stringValue);
     }
diff --git a/src/Clients/Goa.Clients.Bedrock/Serialization/GuardrailTextQualifierConverter.cs b/src/Clients/Goa.Clients.Bedrock/Serialization/GuardrailTextQualifierConverter.cs
index 64b999e0..3eeaf783 100644
--- a/src/Clients/Goa.Clients.Bedrock/Serialization/GuardrailTextQualifierConverter.cs
+++ b/src/Clients/Goa.Clients.Bedrock/Serialization/GuardrailTextQualifierConverter.cs
@@ -1,6 +1,7 @@
 using System.Text.Json;
 using System.Text.Json.Serialization;
 using Goa.Clients.Bedrock.Operations.ApplyGuardrail;
+using Goa.Clients.Core;
 
 namespace Goa.Clients.Bedrock.Serialization;
 
@@ -19,7 +20,7 @@ public override GuardrailTextQualifier Read(ref Utf8JsonReader reader, Type type
             "grounding_source" => GuardrailTextQualifier.GroundingSource,
             "query" => GuardrailTextQualifier.Query,
             "guard_content" => GuardrailTextQualifier.GuardContent,
-            _ => throw new JsonException($"Unknown GuardrailTextQualifier: {value}")
+            _ => Throw.JsonException<GuardrailTextQualifier>($"Unknown GuardrailTextQualifier: {value}")
         };
     }
 
@@ -31,7 +32,7 @@ public override void Write(Utf8JsonWriter writer, GuardrailTextQualifier value,
             GuardrailTextQualifier.GroundingSource => "grounding_source",
             GuardrailTextQualifier.Query => "query",
             GuardrailTextQualifier.GuardContent => "guard_content",
-            _ => throw new JsonException($"Unknown GuardrailTextQualifier: {value}")
+            _ => Throw.JsonException<string>($"Unknown GuardrailTextQualifier: {value}")
         };
         writer.WriteStringValue(stringValue);
     }
diff --git a/src/Clients/Goa.Clients.Bedrock/Serialization/LatencyModeConverter.cs b/src/Clients/Goa.Clients.Bedrock/Serialization/LatencyModeConverter.cs
index 21abd775..8101ef44 100644
--- a/src/Clients/Goa.Clients.Bedrock/Serialization/LatencyModeConverter.cs
+++ b/src/Clients/Goa.Clients.Bedrock/Serialization/LatencyModeConverter.cs
@@ -1,6 +1,7 @@
 using System.Text.Json;
 using System.Text.Json.Serialization;
 using Goa.Clients.Bedrock.Enums;
+using Goa.Clients.Core;
 
 namespace Goa.Clients.Bedrock.Serialization;
 
@@ -18,7 +19,7 @@ public override LatencyMode Read(ref Utf8JsonReader reader, Type typeToConvert,
         {
             "standard" => LatencyMode.Standard,
             "optimized" => LatencyMode.Optimized,
-            _ => throw new JsonException($"Unknown LatencyMode: {value}")
+            _ => Throw.JsonException<LatencyMode>($"Unknown LatencyMode: {value}")
         };
     }
 
@@ -29,7 +30,7 @@ public override void Write(Utf8JsonWriter writer, LatencyMode value, JsonSeriali
         {
             LatencyMode.Standard => "standard",
             LatencyMode.Optimized => "optimized",
-            _ => throw new JsonException($"Unknown LatencyMode: {value}")
+            _ => Throw.JsonException<string>($"Unknown LatencyMode: {value}")
         };
         writer.WriteStringValue(stringValue);
     }
diff --git a/src/Clients/Goa.Clients.Bedrock/Serialization/ServiceTierConverter.cs b/src/Clients/Goa.Clients.Bedrock/Serialization/ServiceTierConverter.cs
index 8db81f37..fad624aa 100644
--- a/src/Clients/Goa.Clients.Bedrock/Serialization/ServiceTierConverter.cs
+++ b/src/Clients/Goa.Clients.Bedrock/Serialization/ServiceTierConverter.cs
@@ -1,6 +1,7 @@
 using System.Text.Json;
 using System.Text.Json.Serialization;
 using Goa.Clients.Bedrock.Models;
+using Goa.Clients.Core;
 
 namespace Goa.Clients.Bedrock.Serialization;
 
@@ -19,7 +20,7 @@ public override ServiceTier Read(ref Utf8JsonReader reader, Type typeToConvert,
             "default" => ServiceTier.Default,
             "priority" => ServiceTier.Priority,
             "flex" => ServiceTier.Flex,
-            _ => throw new JsonException($"Unknown ServiceTier: {value}")
+            _ => Throw.JsonException<ServiceTier>($"Unknown ServiceTier: {value}")
         };
     }
 
@@ -31,7 +32,7 @@ public override void Write(Utf8JsonWriter writer, ServiceTier value, JsonSeriali
             ServiceTier.Default => "default",
             ServiceTier.Priority => "priority",
             ServiceTier.Flex => "flex",
-            _ => throw new JsonException($"Unknown ServiceTier: {value}")
+            _ => Throw.JsonException<string>($"Unknown ServiceTier: {value}")
         };
         writer.WriteStringValue(stringValue);
     }
diff --git a/src/Clients/Goa.Clients.Bedrock/Serialization/StopReasonConverter.cs b/src/Clients/Goa.Clients.Bedrock/Serialization/StopReasonConverter.cs
index ba29002a..da0ac771 100644
--- a/src/Clients/Goa.Clients.Bedrock/Serialization/StopReasonConverter.cs
+++ b/src/Clients/Goa.Clients.Bedrock/Serialization/StopReasonConverter.cs
@@ -1,6 +1,7 @@
 using System.Text.Json;
 using System.Text.Json.Serialization;
 using Goa.Clients.Bedrock.Enums;
+using Goa.Clients.Core;
 
 namespace Goa.Clients.Bedrock.Serialization;
 
@@ -23,7 +24,7 @@ public override StopReason Read(ref Utf8JsonReader reader, Type typeToConvert, J
             "guardrail_intervened" => StopReason.GuardrailIntervened,
             "content_filtered" => StopReason.ContentFiltered,
             "model_context_window_exceeded" => StopReason.ModelContextWindowExceeded,
-            _ => throw new JsonException($"Unknown StopReason: {value}")
+            _ => Throw.JsonException<StopReason>($"Unknown StopReason: {value}")
         };
     }
 
@@ -39,7 +40,7 @@ public override void Write(Utf8JsonWriter writer, StopReason value, JsonSerializ
             StopReason.GuardrailIntervened => "guardrail_intervened",
             StopReason.ContentFiltered => "content_filtered",
             StopReason.ModelContextWindowExceeded => "model_context_window_exceeded",
-            _ => throw new JsonException($"Unknown StopReason: {value}")
+            _ => Throw.JsonException<string>($"Unknown StopReason: {value}")
         };
         writer.WriteStringValue(stringValue);
     }
diff --git a/src/Clients/Goa.Clients.Core/AwsServiceClient.cs b/src/Clients/Goa.Clients.Core/AwsServiceClient.cs
index c60d3953..ea48fb86 100644
--- a/src/Clients/Goa.Clients.Core/AwsServiceClient.cs
+++ b/src/Clients/Goa.Clients.Core/AwsServiceClient.cs
@@ -2,6 +2,7 @@
 using Goa.Clients.Core.Http;
 using Goa.Clients.Core.Logging;
 using Microsoft.Extensions.Logging;
+using System.Buffers;
 using System.Diagnostics;
 using System.Net.Http.Headers;
 
@@ -23,6 +24,17 @@ public abstract class AwsServiceClient<T> where T : AwsServiceConfiguration
     /// </summary>
     public const string XAmzErrorType = "x-amzn-ErrorType";
 
+    private const string LogKeyClient = "Client";
+    private const string LogKeyRegion = "Region";
+    private const string LogKeyService = "Service";
+    private const string LogKeySigningService = "SigningService";
+    private const string LogKeyTarget = "Target";
+    private const string LogKeyApiVersion = "ApiVersion";
+    private const string LogKeyMethod = "Method";
+    private const string LogKeyUri = "Uri";
+    private const string LogKeyStatusCode = "StatusCode";
+    private const string LogKeyReasonPhrase = "ReasonPhrase";
+
     private readonly IHttpClientFactory _httpClientFactory;
     private readonly string _clientType;
     private Uri? _cachedBaseUri;
@@ -67,16 +79,18 @@ protected async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request,
         request.Options.Set(HttpOptions.Target, target);
         request.Options.Set(HttpOptions.ApiVersion, Configuration.ApiVersion);
 
-        using var logContext = Logger.BeginScope(new LogScope8(
-            new("Client", _clientType),
-            new("Region", Configuration.Region),
-            new("Service", Configuration.Service),
-            new("SigningService", Configuration.SigningService),
-            new("Target", target),
-            new("ApiVersion", Configuration.ApiVersion),
-            new("Method", request.Method.Method),
-            new("Uri", request.RequestUri?.AbsoluteUri ?? "Unknown")
-        ));
+        using var logContext = Logger.IsEnabled(Configuration.LogLevel)
+            ? Logger.BeginScope(new LogScope8(
+                new(LogKeyClient, _clientType),
+                new(LogKeyRegion, Configuration.Region),
+                new(LogKeyService, Configuration.Service),
+                new(LogKeySigningService, Configuration.SigningService),
+                new(LogKeyTarget, target),
+                new(LogKeyApiVersion, Configuration.ApiVersion),
+                new(LogKeyMethod, request.Method.Method),
+                new(LogKeyUri, request.RequestUri?.AbsoluteUri ?? "Unknown")
+            ))
+            : null;
 
         try
         {
@@ -85,18 +99,33 @@ protected async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request,
             var start = Stopwatch.GetTimestamp();
             var response = await client.SendAsync(request, cancellationToken);
 
-            // Ensure that we log the applicable response headers and status code
-            var context = new Dictionary<string, object>
-            {
-                ["StatusCode"] = ((int)response.StatusCode).ToString(),
-                ["ReasonPhrase"] = response.ReasonPhrase ?? response.StatusCode.ToString()
-            };
-            foreach (var header in response.Headers)
+            // Log fixed response fields with zero-allocation scope
+            using var responseLogContext = Logger.IsEnabled(Configuration.LogLevel)
+                ? Logger.BeginScope(new LogScope2(
+                    new(LogKeyStatusCode, GetStatusCodeString(response.StatusCode)),
+                    new(LogKeyReasonPhrase, response.ReasonPhrase ?? GetStatusCodeString(response.StatusCode))
+                ))
+                : null;
+
+            // Log x-amz response headers separately with capacity hint
+            IDisposable? amzLogContext = null;
+            if (Logger.IsEnabled(Configuration.LogLevel))
             {
-                if (header.Key.StartsWith("x-amz", StringComparison.OrdinalIgnoreCase))
-                    context[header.Key] = string.Join(", ", header.Value);
+                Dictionary<string, object>? amzHeaders = null;
+                foreach (var header in response.Headers.NonValidated)
+                {
+                    if (header.Key.StartsWith("x-amz", StringComparison.OrdinalIgnoreCase))
+                    {
+                        amzHeaders ??= new Dictionary<string, object>(4);
+#pragma warning disable GOA1501 // Boxing HeaderStringValues to object is required for ILogger.BeginScope
+                        amzHeaders[header.Key] = string.Join(", ", header.Value);
+#pragma warning restore GOA1501
+                    }
+                }
+                if (amzHeaders is not null)
+                    amzLogContext = Logger.BeginScope(amzHeaders);
             }
-            using var responseLogContext = Logger.BeginScope(context);
+            using var _ = amzLogContext;
 
             Logger.RequestComplete(Configuration.LogLevel, Stopwatch.GetElapsedTime(start).TotalMilliseconds);
 
@@ -109,6 +138,46 @@ protected async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request,
         }
     }
 
+    /// <summary>
+    /// Applies AWS-specific error header processing to the error object.
+    /// </summary>
+    protected static ApiError ProcessAwsErrorHeaders(HttpResponseMessage response, ApiError error)
+    {
+        if (response.Headers.TryGetValues(XAmznErrorMessage, out var messages))
+        {
+            error = error with { Message = string.Join(", ", messages) };
+        }
+
+        if (string.IsNullOrWhiteSpace(error.Type) && response.Headers.TryGetValues(XAmzErrorType, out var types))
+        {
+            error = error with { Type = string.Join(", ", types) };
+        }
+
+        var infoSeparator = error.Type?.LastIndexOf(':') ?? -1;
+        if (infoSeparator > 0)
+        {
+            error = error with { Type = error.Type![..infoSeparator] };
+        }
+
+        var typeSeparator = error.Type?.LastIndexOf('#') ?? -1;
+        if (typeSeparator > 0)
+        {
+            error = error with { Type = error.Type![(typeSeparator + 1)..] };
+        }
+
+        return error;
+    }
+
+    private static string GetStatusCodeString(System.Net.HttpStatusCode statusCode) => statusCode switch
+    {
+        System.Net.HttpStatusCode.OK => "200", System.Net.HttpStatusCode.Created => "201", System.Net.HttpStatusCode.Accepted => "202", System.Net.HttpStatusCode.NoContent => "204",
+        System.Net.HttpStatusCode.MovedPermanently => "301", System.Net.HttpStatusCode.Found => "302", System.Net.HttpStatusCode.NotModified => "304",
+        System.Net.HttpStatusCode.BadRequest => "400", System.Net.HttpStatusCode.Unauthorized => "401", System.Net.HttpStatusCode.Forbidden => "403", System.Net.HttpStatusCode.NotFound => "404",
+        System.Net.HttpStatusCode.Conflict => "409", System.Net.HttpStatusCode.TooManyRequests => "429",
+        System.Net.HttpStatusCode.InternalServerError => "500", System.Net.HttpStatusCode.BadGateway => "502", System.Net.HttpStatusCode.ServiceUnavailable => "503", System.Net.HttpStatusCode.GatewayTimeout => "504",
+        _ => ((int)statusCode).ToString()
+    };
+
     /// <summary>
     /// Creates an HTTP request message with the specified content.
     /// </summary>
@@ -209,4 +278,123 @@ protected HttpRequestMessage CreateRequestMessage(HttpMethod method, string requ
 
         return requestMessage;
     }
+
+    /// <summary>
+    /// Maximum allowed response size in bytes (4 MB).
+    /// </summary>
+    protected const int MaxResponseSize = 4 * 1024 * 1024;
+
+    /// <summary>
+    /// Reads the HTTP response body into a pooled byte buffer for zero-copy deserialization.
+    /// </summary>
+    /// <param name="response">The HTTP response message.</param>
+    /// <param name="cancellationToken">Token to cancel the operation.</param>
+    /// <returns>A pooled buffer containing the response bytes. Must be disposed after use.</returns>
+    protected static async Task<PooledBuffer> ReadResponseBytesAsync(
+        HttpResponseMessage response, CancellationToken cancellationToken)
+    {
+        var headerLength = response.Content.Headers.ContentLength;
+        if (headerLength is 0)
+            return default;
+
+        if (headerLength is not null)
+        {
+            if (headerLength < 0 || headerLength > MaxResponseSize)
+                Throw.InvalidOperation($"Response Content-Length {headerLength} exceeds maximum {MaxResponseSize} bytes.");
+
+            var contentLength = (int)headerLength;
+            var knownBuffer = ArrayPool<byte>.Shared.Rent(contentLength);
+            try
+            {
+                var stream = await response.Content.ReadAsStreamAsync(cancellationToken);
+                var totalRead = 0;
+                while (totalRead < contentLength)
+                {
+                    var read = await stream.ReadAsync(knownBuffer.AsMemory(totalRead, contentLength - totalRead), cancellationToken);
+                    if (read == 0) break;
+                    totalRead += read;
+                }
+                return new PooledBuffer(knownBuffer, totalRead);
+            }
+            catch
+            {
+                ArrayPool<byte>.Shared.Return(knownBuffer);
+                throw;
+            }
+        }
+
+        const int initialSize = 4096;
+        var buffer = ArrayPool<byte>.Shared.Rent(initialSize);
+        try
+        {
+            var stream = await response.Content.ReadAsStreamAsync(cancellationToken);
+            var totalRead = 0;
+            while (true)
+            {
+                if (totalRead == buffer.Length)
+                {
+                    var newSize = buffer.Length * 2;
+                    if (newSize > MaxResponseSize)
+                        newSize = MaxResponseSize + 1; // allow one more read to detect overflow
+
+                    var newBuffer = ArrayPool<byte>.Shared.Rent(newSize);
+                    buffer.AsSpan(0, totalRead).CopyTo(newBuffer);
+                    ArrayPool<byte>.Shared.Return(buffer);
+                    buffer = newBuffer;
+                }
+
+                var read = await stream.ReadAsync(buffer.AsMemory(totalRead, buffer.Length - totalRead), cancellationToken);
+                if (read == 0) break;
+                totalRead += read;
+
+                if (totalRead > MaxResponseSize)
+                    Throw.InvalidOperation($"Response size exceeds maximum {MaxResponseSize} bytes.");
+            }
+
+            if (totalRead == 0)
+            {
+                ArrayPool<byte>.Shared.Return(buffer);
+                return default;
+            }
+
+            return new PooledBuffer(buffer, totalRead);
+        }
+        catch
+        {
+            ArrayPool<byte>.Shared.Return(buffer);
+            throw;
+        }
+    }
+
+    /// <summary>
+    /// A disposable buffer backed by ArrayPool for zero-allocation response reading.
+    /// </summary>
+    protected struct PooledBuffer : IDisposable
+    {
+        private byte[]? _buffer;
+
+        /// <summary>The number of valid bytes in the buffer.</summary>
+        public readonly int Length;
+
+        /// <summary>Creates a new PooledBuffer wrapping the given rented array.</summary>
+        public PooledBuffer(byte[] buffer, int length)
+        {
+            _buffer = buffer;
+            Length = length;
+        }
+
+        /// <summary>Gets a read-only span over the valid portion of the buffer.</summary>
+        public readonly ReadOnlySpan<byte> Span => _buffer is null ? default : _buffer.AsSpan(0, Length);
+
+        /// <summary>Returns the rented buffer to the shared ArrayPool.</summary>
+        public void Dispose()
+        {
+            var buf = _buffer;
+            if (buf is not null)
+            {
+                _buffer = null;
+                ArrayPool<byte>.Shared.Return(buf);
+            }
+        }
+    }
 }
diff --git a/src/Clients/Goa.Clients.Core/Http/ApiErrorReader.cs b/src/Clients/Goa.Clients.Core/Http/ApiErrorReader.cs
index 2ddd6470..af09a609 100644
--- a/src/Clients/Goa.Clients.Core/Http/ApiErrorReader.cs
+++ b/src/Clients/Goa.Clients.Core/Http/ApiErrorReader.cs
@@ -1,3 +1,5 @@
+using System.Buffers;
+using System.Text;
 using System.Text.Json;
 
 namespace Goa.Clients.Core.Http;
@@ -8,19 +10,19 @@ namespace Goa.Clients.Core.Http;
 internal static class ApiErrorReader
 {
     /// <summary>
-    /// Reads an ApiError from a JSON string using Utf8JsonReader.
+    /// Reads an ApiError from UTF-8 bytes using Utf8JsonReader.
     /// Matches fields case-insensitively: "message", "__type", "code".
     /// </summary>
-    /// <param name="content">The JSON string to deserialize.</param>
+    /// <param name="utf8Json">The UTF-8 encoded JSON bytes to deserialize.</param>
     /// <returns>The deserialized ApiError, or null if the input is malformed or empty.</returns>
-    public static ApiError? ReadApiError(string content)
+    public static ApiError? ReadApiError(ReadOnlySpan<byte> utf8Json)
     {
-        if (string.IsNullOrWhiteSpace(content))
+        if (utf8Json.IsEmpty)
             return null;
 
         try
         {
-            var reader = new Utf8JsonReader(System.Text.Encoding.UTF8.GetBytes(content));
+            var reader = new Utf8JsonReader(utf8Json);
 
             if (!reader.Read() || reader.TokenType != JsonTokenType.StartObject)
                 return null;
@@ -68,4 +70,36 @@ internal static class ApiErrorReader
             return null;
         }
     }
+
+    /// <summary>
+    /// Reads an ApiError from a JSON string using Utf8JsonReader.
+    /// Uses stackalloc for small payloads, ArrayPool for larger ones.
+    /// </summary>
+    /// <param name="content">The JSON string to deserialize.</param>
+    /// <returns>The deserialized ApiError, or null if the input is malformed or empty.</returns>
+    public static ApiError? ReadApiError(string content)
+    {
+        if (string.IsNullOrWhiteSpace(content))
+            return null;
+
+        var byteCount = Encoding.UTF8.GetByteCount(content);
+
+        if (byteCount <= 1024)
+        {
+            Span<byte> buffer = stackalloc byte[byteCount];
+            Encoding.UTF8.GetBytes(content, buffer);
+            return ReadApiError((ReadOnlySpan<byte>)buffer);
+        }
+
+        var rented = ArrayPool<byte>.Shared.Rent(byteCount);
+        try
+        {
+            var written = Encoding.UTF8.GetBytes(content, rented);
+            return ReadApiError(rented.AsSpan(0, written));
+        }
+        finally
+        {
+            ArrayPool<byte>.Shared.Return(rented);
+        }
+    }
 }
diff --git a/src/Clients/Goa.Clients.Core/Http/ApiResponse.cs b/src/Clients/Goa.Clients.Core/Http/ApiResponse.cs
index 476101af..c1afc279 100644
--- a/src/Clients/Goa.Clients.Core/Http/ApiResponse.cs
+++ b/src/Clients/Goa.Clients.Core/Http/ApiResponse.cs
@@ -17,9 +17,9 @@ public sealed class ApiResponse<T>
     public ApiError? Error { get; }
 
     /// <summary>
-    /// Gets the HTTP response headers.
+    /// Gets the Content-Type of the response body.
     /// </summary>
-    public ResponseHeaders? Headers { get; }
+    public string? ContentType { get; }
 
     /// <summary>
     /// Gets a value indicating whether the operation was successful.
@@ -36,14 +36,14 @@ public ApiResponse(T? value)
     }
 
     /// <summary>
-    /// Initializes a new instance with a successful response value and headers.
+    /// Initializes a new instance with a successful response value and content type.
     /// </summary>
     /// <param name="value">The successful response value.</param>
-    /// <param name="headers">The HTTP response headers.</param>
-    public ApiResponse(T? value, ResponseHeaders? headers)
+    /// <param name="contentType">The Content-Type of the response body.</param>
+    public ApiResponse(T? value, string? contentType)
     {
         Value = value;
-        Headers = headers;
+        ContentType = contentType;
     }
 
     /// <summary>
diff --git a/src/Clients/Goa.Clients.Core/Http/RequestSigner.cs b/src/Clients/Goa.Clients.Core/Http/RequestSigner.cs
index ba3ed03c..4ee4e666 100644
--- a/src/Clients/Goa.Clients.Core/Http/RequestSigner.cs
+++ b/src/Clients/Goa.Clients.Core/Http/RequestSigner.cs
@@ -1,6 +1,7 @@
 using Goa.Clients.Core.Credentials;
 using System.Buffers;
 using System.Diagnostics.CodeAnalysis;
+using System.Net.Http.Headers;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using System.Security.Cryptography;
@@ -29,6 +30,12 @@ internal sealed class RequestSigner
     private static readonly string? _cachedAwsRegion = Environment.GetEnvironmentVariable("AWS_REGION");
     private const string RootPath = "/";
     private const string CredentialSuffix = "/aws4_request";
+    private const string HeaderHost = "host";
+    private const string HeaderAmzContentSha256 = "x-amz-content-sha256";
+    private const string HeaderAmzDate = "x-amz-date";
+    private const string HeaderAmzTarget = "x-amz-target";
+    private const string HeaderAmzApiVersion = "x-amz-api-version";
+    private const string HeaderAmzSecurityToken = "x-amz-security-token";
 
     private readonly ICredentialProviderChain _credentialProvider;
 
@@ -59,7 +66,7 @@ public async ValueTask<string> SignRequestAsync(HttpRequestMessage request, Date
                 if (i != 0) sb.Append("; ");
                 sb.Append(errs[i].Description);
             }
-            ThrowInvalidOperationException($"Failed to retrieve AWS credentials: {sb}");
+            Throw.InvalidOperation($"Failed to retrieve AWS credentials: {sb}");
         }
         var credentials = credentialsResult.Value;
 
@@ -146,7 +153,7 @@ private async ValueTask<string> SignRequestWithCredentialsAsync(
                 if (i != 0) sb.Append("; ");
                 sb.Append(errs[i].Description);
             }
-            ThrowInvalidOperationException($"Failed to retrieve AWS credentials: {sb}");
+            Throw.InvalidOperation($"Failed to retrieve AWS credentials: {sb}");
         }
         var credentials = credentialsResult.Value;
 
@@ -229,11 +236,11 @@ private async ValueTask<string> SignRequestWithCredentialsAsync(
         // ---- Build Canonical Request with precise memory management ----
         // Enumerate headers ONCE into rented arrays to avoid repeated GetEnumeratorCore allocations
         const int InitialHeaderCapacity = 16;
-        var reqHeaders = ArrayPool<KeyValuePair<string, IEnumerable<string>>>.Shared.Rent(InitialHeaderCapacity);
-        var contentHeaders = ArrayPool<KeyValuePair<string, IEnumerable<string>>>.Shared.Rent(InitialHeaderCapacity);
+        var reqHeaders = ArrayPool<KeyValuePair<string, HeaderStringValues>>.Shared.Rent(InitialHeaderCapacity);
+        var contentHeaders = ArrayPool<KeyValuePair<string, HeaderStringValues>>.Shared.Rent(InitialHeaderCapacity);
         int rhIndex = 0, chIndex = 0;
 
-        foreach (var kv in request.Headers)
+        foreach (var kv in request.Headers.NonValidated)
         {
             if (rhIndex == reqHeaders.Length)
                 reqHeaders = GrowArray(reqHeaders, ref rhIndex);
@@ -241,7 +248,7 @@ private async ValueTask<string> SignRequestWithCredentialsAsync(
         }
 
         if (request.Content?.Headers is not null)
-            foreach (var kv in request.Content.Headers)
+            foreach (var kv in request.Content.Headers.NonValidated)
             {
                 if (chIndex == contentHeaders.Length)
                     contentHeaders = GrowArray(contentHeaders, ref chIndex);
@@ -268,13 +275,13 @@ private async ValueTask<string> SignRequestWithCredentialsAsync(
 
         // Build AWS required headers first
         if (request.RequestUri is not null)
-            headerRefs[hrefIndex++] = HeaderRef.Create("host", HeaderKind.Host, -1);
-        headerRefs[hrefIndex++] = HeaderRef.Create("x-amz-content-sha256", HeaderKind.AmzSha256, -1);
-        headerRefs[hrefIndex++] = HeaderRef.Create("x-amz-date", HeaderKind.AmzDate, -1);
+            headerRefs[hrefIndex++] = HeaderRef.Create(HeaderHost, HeaderKind.Host, -1);
+        headerRefs[hrefIndex++] = HeaderRef.Create(HeaderAmzContentSha256, HeaderKind.AmzSha256, -1);
+        headerRefs[hrefIndex++] = HeaderRef.Create(HeaderAmzDate, HeaderKind.AmzDate, -1);
 
-        if (hasApiVersion) headerRefs[hrefIndex++] = HeaderRef.Create("x-amz-api-version", HeaderKind.AmzApiVersion, -1);
-        if (!string.IsNullOrWhiteSpace(credentials.SessionToken)) headerRefs[hrefIndex++] = HeaderRef.Create("x-amz-security-token", HeaderKind.AmzSecurityToken, -1);
-        if (hasTarget) headerRefs[hrefIndex++] = HeaderRef.Create("x-amz-target", HeaderKind.AmzTarget, -1);
+        if (hasApiVersion) headerRefs[hrefIndex++] = HeaderRef.Create(HeaderAmzApiVersion, HeaderKind.AmzApiVersion, -1);
+        if (!string.IsNullOrWhiteSpace(credentials.SessionToken)) headerRefs[hrefIndex++] = HeaderRef.Create(HeaderAmzSecurityToken, HeaderKind.AmzSecurityToken, -1);
+        if (hasTarget) headerRefs[hrefIndex++] = HeaderRef.Create(HeaderAmzTarget, HeaderKind.AmzTarget, -1);
 
         // Add request headers from cached array, skipping AWS-managed headers
         var filteredIndex = 0;
@@ -461,8 +468,8 @@ private async ValueTask<string> SignRequestWithCredentialsAsync(
 
         // Return rented arrays
         ArrayPool<HeaderRef>.Shared.Return(headerRefs);
-        ArrayPool<KeyValuePair<string, IEnumerable<string>>>.Shared.Return(reqHeaders);
-        ArrayPool<KeyValuePair<string, IEnumerable<string>>>.Shared.Return(contentHeaders);
+        ArrayPool<KeyValuePair<string, HeaderStringValues>>.Shared.Return(reqHeaders);
+        ArrayPool<KeyValuePair<string, HeaderStringValues>>.Shared.Return(contentHeaders);
 
         return (signature, signedHeaders);
     }
@@ -664,8 +671,8 @@ private static int WriteHeaderValue(
         in HeaderRef r,
         HttpRequestMessage req,
         AwsCredentials creds,
-        KeyValuePair<string, IEnumerable<string>>[] reqHeaders,
-        KeyValuePair<string, IEnumerable<string>>[] contentHeaders,
+        KeyValuePair<string, HeaderStringValues>[] reqHeaders,
+        KeyValuePair<string, HeaderStringValues>[] contentHeaders,
         ReadOnlySpan<char> longDate,
         ReadOnlySpan<byte> payloadHashBytes)
     {
@@ -729,7 +736,7 @@ private static int WriteHost(Span<char> dest, Uri u)
     /// Collapses whitespace and joins with commas as per HTTP/AWS specifications.
     /// </summary>
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    private static int WriteNormalizedJoined(Span<char> dest, IEnumerable<string> values)
+    private static int WriteNormalizedJoined(Span<char> dest, HeaderStringValues values)
     {
         var pos = 0; var firstVal = true;
         foreach (var raw in values)
@@ -756,8 +763,8 @@ private static int WriteNormalizedJoined(Span<char> dest, IEnumerable<string> va
     private static int EstimateHeadersCharCount(
         HeaderRef[] refs, int count,
         HttpRequestMessage req, AwsCredentials creds,
-        KeyValuePair<string, IEnumerable<string>>[] reqHeaders,
-        KeyValuePair<string, IEnumerable<string>>[] contentHeaders)
+        KeyValuePair<string, HeaderStringValues>[] reqHeaders,
+        KeyValuePair<string, HeaderStringValues>[] contentHeaders)
     {
         var total = 0;
         for (var i = 0; i < count; i++)
@@ -885,10 +892,10 @@ private static (string region, string serviceName) GetRequestParameters(HttpRequ
             region = regionOption;
 
         if (string.IsNullOrWhiteSpace(region))
-            ThrowInvalidOperationException("Region is required");
+            Throw.InvalidOperation("Region is required");
 
         if (!request.Options.TryGetValue(HttpOptions.Service, out var service) || string.IsNullOrWhiteSpace(service))
-            ThrowInvalidOperationException("Service name is required");
+            Throw.InvalidOperation("Service name is required");
 
         return (region!, service);
     }
@@ -1101,25 +1108,14 @@ private static string BuildSignedHeadersFromRefs(HeaderRef[] headerRefs, int cou
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     private static bool IsAwsManagedHeader(string headerName)
     {
-        return string.Equals(headerName, "Host", StringComparison.OrdinalIgnoreCase) ||
-               string.Equals(headerName, "x-amz-content-sha256", StringComparison.OrdinalIgnoreCase) ||
-               string.Equals(headerName, "x-amz-date", StringComparison.OrdinalIgnoreCase) ||
-               string.Equals(headerName, "x-amz-target", StringComparison.OrdinalIgnoreCase) ||
-               string.Equals(headerName, "x-amz-api-version", StringComparison.OrdinalIgnoreCase) ||
-               string.Equals(headerName, "x-amz-security-token", StringComparison.OrdinalIgnoreCase);
+        return string.Equals(headerName, HeaderHost, StringComparison.OrdinalIgnoreCase) ||
+               string.Equals(headerName, HeaderAmzContentSha256, StringComparison.OrdinalIgnoreCase) ||
+               string.Equals(headerName, HeaderAmzDate, StringComparison.OrdinalIgnoreCase) ||
+               string.Equals(headerName, HeaderAmzTarget, StringComparison.OrdinalIgnoreCase) ||
+               string.Equals(headerName, HeaderAmzApiVersion, StringComparison.OrdinalIgnoreCase) ||
+               string.Equals(headerName, HeaderAmzSecurityToken, StringComparison.OrdinalIgnoreCase);
     }
 
-    /// <summary>
-    /// Exception helpers with no-inlining to keep hot paths small.
-    /// </summary>
-    [MethodImpl(MethodImplOptions.NoInlining)]
-    [DoesNotReturn]
-    private static void ThrowInvalidOperationException(string message) => throw new InvalidOperationException(message);
-
-    [MethodImpl(MethodImplOptions.NoInlining)]
-    [DoesNotReturn]
-    private static void ThrowArgumentNullException(string paramName) => throw new ArgumentNullException(paramName);
-
     /// <summary>
     /// Creates credential scope string for AWS signature computation.
     /// </summary>
diff --git a/src/Clients/Goa.Clients.Core/Http/ResponseHeaders.cs b/src/Clients/Goa.Clients.Core/Http/ResponseHeaders.cs
deleted file mode 100644
index 40e54db1..00000000
--- a/src/Clients/Goa.Clients.Core/Http/ResponseHeaders.cs
+++ /dev/null
@@ -1,62 +0,0 @@
-using System.Net.Http.Headers;
-
-namespace Goa.Clients.Core.Http;
-
-/// <summary>
-/// Lightweight representation of key AWS response headers.
-/// </summary>
-public sealed class ResponseHeaders
-{
-    /// <summary>
-    /// Gets the AWS request ID from the response headers.
-    /// </summary>
-    public string? RequestId { get; init; }
-
-    /// <summary>
-    /// Gets the error type from the response headers.
-    /// </summary>
-    public string? ErrorType { get; init; }
-
-    /// <summary>
-    /// Gets the error message from the response headers.
-    /// </summary>
-    public string? ErrorMessage { get; init; }
-
-    /// <summary>
-    /// Gets the Content-Type of the response body.
-    /// </summary>
-    public string? ContentType { get; init; }
-
-    /// <summary>
-    /// Extracts key headers from an HTTP response.
-    /// </summary>
-    internal static ResponseHeaders FromHttpResponse(HttpResponseHeaders headers, HttpContentHeaders? contentHeaders = null)
-    {
-        string? requestId = null;
-        if (headers.TryGetValues("x-amzn-RequestId", out var values)
-            || headers.TryGetValues("x-amz-request-id", out values))
-        {
-            requestId = values.FirstOrDefault();
-        }
-
-        string? errorType = null;
-        if (headers.TryGetValues("x-amzn-ErrorType", out var typeValues))
-        {
-            errorType = typeValues.FirstOrDefault();
-        }
-
-        string? errorMessage = null;
-        if (headers.TryGetValues("x-amzn-ErrorMessage", out var errorValues))
-        {
-            errorMessage = errorValues.FirstOrDefault();
-        }
-
-        return new ResponseHeaders
-        {
-            RequestId = requestId,
-            ErrorType = errorType,
-            ErrorMessage = errorMessage,
-            ContentType = contentHeaders?.ContentType?.MediaType
-        };
-    }
-}
diff --git a/src/Clients/Goa.Clients.Core/JsonAwsServiceClient.cs b/src/Clients/Goa.Clients.Core/JsonAwsServiceClient.cs
index d7751b8e..715c1113 100644
--- a/src/Clients/Goa.Clients.Core/JsonAwsServiceClient.cs
+++ b/src/Clients/Goa.Clients.Core/JsonAwsServiceClient.cs
@@ -2,7 +2,6 @@
 using Goa.Clients.Core.Http;
 using Goa.Clients.Core.Logging;
 using Microsoft.Extensions.Logging;
-using System.Buffers;
 
 using System.Net.Http.Headers;
 using System.Text;
@@ -95,8 +94,8 @@ protected async Task<ApiResponse<TResponse>> ProcessJsonResponseAsync<TResponse>
                 return new ApiResponse<TResponse>(new ApiError("Request not successful.") { StatusCode = response.StatusCode });
             }
 
+            var error = ApiErrorReader.ReadApiError(errorBuffer.Span);
             var errorPayload = Encoding.UTF8.GetString(errorBuffer.Span);
-            var error = DeserializeJsonError(errorPayload);
             if (error is not null)
             {
                 error = error with
@@ -117,22 +116,22 @@ protected async Task<ApiResponse<TResponse>> ProcessJsonResponseAsync<TResponse>
             return new ApiResponse<TResponse>(error);
         }
 
-        var headers = ResponseHeaders.FromHttpResponse(response.Headers, response.Content.Headers);
+        var contentType = response.Content.Headers.ContentType?.MediaType;
         using var pooledBuffer = await ReadResponseBytesAsync(response, cancellationToken);
 
         if (typeof(TResponse) == typeof(string))
         {
             var str = pooledBuffer.Length > 0 ? Encoding.UTF8.GetString(pooledBuffer.Span) : string.Empty;
-            return new ApiResponse<TResponse>(str as TResponse, headers);
+            return new ApiResponse<TResponse>(str as TResponse, contentType);
         }
 
         if (pooledBuffer.Length == 0)
-            return new ApiResponse<TResponse>(default(TResponse), headers);
+            return new ApiResponse<TResponse>(default(TResponse), contentType);
 
         var typeInfo = ResolveJsonTypeInfo<TResponse>();
         var jsonReader = new Utf8JsonReader(pooledBuffer.Span);
         var result = JsonSerializer.Deserialize(ref jsonReader, typeInfo);
-        return new ApiResponse<TResponse>(result, headers);
+        return new ApiResponse<TResponse>(result, contentType);
     }
 
     /// <summary>
@@ -143,40 +142,6 @@ protected async Task<ApiResponse<TResponse>> ProcessJsonResponseAsync<TResponse>
     /// <returns>The resolved JSON type info.</returns>
     protected abstract JsonTypeInfo<TValue> ResolveJsonTypeInfo<TValue>();
 
-    /// <summary>
-    /// Applies AWS-specific error header processing to the error object.
-    /// </summary>
-    protected ApiError ProcessAwsErrorHeaders(HttpResponseMessage response, ApiError error)
-    {
-        // Logic: https://github.com/aws/aws-sdk-net/blob/a9aa4e78a927e1021114b6531e21fc25f87e0dd9/sdk/src/Core/Amazon.Runtime/Internal/Transform/JsonErrorResponseUnmarshaller.cs#L79
-        if (response.Headers.TryGetValues(XAmznErrorMessage, out var messages))
-        {
-            error = error with { Message = string.Join(", ", messages) };
-        }
-
-        // Logic: https://github.com/aws/aws-sdk-net/blob/a9aa4e78a927e1021114b6531e21fc25f87e0dd9/sdk/src/Core/Amazon.Runtime/Internal/Transform/JsonErrorResponseUnmarshaller.cs#L60
-        if (string.IsNullOrWhiteSpace(error.Type) && response.Headers.TryGetValues(XAmzErrorType, out var types))
-        {
-            error = error with { Type = string.Join(", ", types) };
-        }
-
-        // Logic: https://github.com/aws/aws-sdk-net/blob/a9aa4e78a927e1021114b6531e21fc25f87e0dd9/sdk/src/Core/Amazon.Runtime/Internal/Transform/JsonErrorResponseUnmarshaller.cs#L68
-        var infoSeparator = error.Type?.LastIndexOf(':') ?? -1;
-        if (infoSeparator > 0)
-        {
-            error = error with { Type = error.Type![..infoSeparator] };
-        }
-
-        // Logic: https://github.com/aws/aws-sdk-net/blob/a9aa4e78a927e1021114b6531e21fc25f87e0dd9/sdk/src/Core/Amazon.Runtime/Internal/Transform/JsonErrorResponseUnmarshaller.cs#L95
-        var typeSeparator = error.Type?.LastIndexOf('#') ?? -1;
-        if (typeSeparator > 0)
-        {
-            error = error with { Type = error.Type![(typeSeparator + 1)..] };
-        }
-
-        return error;
-    }
-
     /// <summary>
     /// Deserializes JSON error response content to an ApiError.
     /// </summary>
@@ -187,126 +152,7 @@ protected ApiError ProcessAwsErrorHeaders(HttpResponseMessage response, ApiError
     /// </summary>
     private static bool IsJsonSerialized(string input)
     {
-        var trimmed = input.TrimStart();
-        return trimmed.StartsWith('{') || trimmed.StartsWith('[');
-    }
-
-    /// <summary>
-    /// Maximum allowed response size in bytes (4 MB).
-    /// </summary>
-    protected const int MaxResponseSize = 4 * 1024 * 1024;
-
-    /// <summary>
-    /// Reads the HTTP response body into a pooled byte buffer for zero-copy deserialization.
-    /// </summary>
-    /// <param name="response">The HTTP response message.</param>
-    /// <param name="cancellationToken">Token to cancel the operation.</param>
-    /// <returns>A pooled buffer containing the response bytes. Must be disposed after use.</returns>
-    protected static async Task<PooledBuffer> ReadResponseBytesAsync(
-        HttpResponseMessage response, CancellationToken cancellationToken)
-    {
-        var headerLength = response.Content.Headers.ContentLength;
-        if (headerLength is 0)
-            return default;
-
-        if (headerLength is not null)
-        {
-            if (headerLength < 0 || headerLength > MaxResponseSize)
-                throw new InvalidOperationException($"Response Content-Length {headerLength} exceeds maximum {MaxResponseSize} bytes.");
-
-            var contentLength = (int)headerLength;
-            var knownBuffer = System.Buffers.ArrayPool<byte>.Shared.Rent(contentLength);
-            try
-            {
-                var stream = await response.Content.ReadAsStreamAsync(cancellationToken);
-                var totalRead = 0;
-                while (totalRead < contentLength)
-                {
-                    var read = await stream.ReadAsync(knownBuffer.AsMemory(totalRead, contentLength - totalRead), cancellationToken);
-                    if (read == 0) break;
-                    totalRead += read;
-                }
-                return new PooledBuffer(knownBuffer, totalRead);
-            }
-            catch
-            {
-                System.Buffers.ArrayPool<byte>.Shared.Return(knownBuffer);
-                throw;
-            }
-        }
-
-        const int initialSize = 4096;
-        var buffer = System.Buffers.ArrayPool<byte>.Shared.Rent(initialSize);
-        try
-        {
-            var stream = await response.Content.ReadAsStreamAsync(cancellationToken);
-            var totalRead = 0;
-            while (true)
-            {
-                if (totalRead == buffer.Length)
-                {
-                    var newSize = buffer.Length * 2;
-                    if (newSize > MaxResponseSize)
-                        newSize = MaxResponseSize + 1; // allow one more read to detect overflow
-
-                    var newBuffer = System.Buffers.ArrayPool<byte>.Shared.Rent(newSize);
-                    buffer.AsSpan(0, totalRead).CopyTo(newBuffer);
-                    System.Buffers.ArrayPool<byte>.Shared.Return(buffer);
-                    buffer = newBuffer;
-                }
-
-                var read = await stream.ReadAsync(buffer.AsMemory(totalRead, buffer.Length - totalRead), cancellationToken);
-                if (read == 0) break;
-                totalRead += read;
-
-                if (totalRead > MaxResponseSize)
-                    throw new InvalidOperationException($"Response size exceeds maximum {MaxResponseSize} bytes.");
-            }
-
-            if (totalRead == 0)
-            {
-                System.Buffers.ArrayPool<byte>.Shared.Return(buffer);
-                return default;
-            }
-
-            return new PooledBuffer(buffer, totalRead);
-        }
-        catch
-        {
-            System.Buffers.ArrayPool<byte>.Shared.Return(buffer);
-            throw;
-        }
-    }
-
-    /// <summary>
-    /// A disposable buffer backed by ArrayPool for zero-allocation response reading.
-    /// </summary>
-    protected struct PooledBuffer : IDisposable
-    {
-        private byte[]? _buffer;
-
-        /// <summary>The number of valid bytes in the buffer.</summary>
-        public readonly int Length;
-
-        /// <summary>Creates a new PooledBuffer wrapping the given rented array.</summary>
-        public PooledBuffer(byte[] buffer, int length)
-        {
-            _buffer = buffer;
-            Length = length;
-        }
-
-        /// <summary>Gets a read-only span over the valid portion of the buffer.</summary>
-        public readonly ReadOnlySpan<byte> Span => _buffer is null ? default : _buffer.AsSpan(0, Length);
-
-        /// <summary>Returns the rented buffer to the shared ArrayPool.</summary>
-        public void Dispose()
-        {
-            var buf = _buffer;
-            if (buf is not null)
-            {
-                _buffer = null;
-                System.Buffers.ArrayPool<byte>.Shared.Return(buf);
-            }
-        }
+        var trimmed = input.AsSpan().TrimStart();
+        return trimmed.StartsWith("{") || trimmed.StartsWith("[");
     }
 }
diff --git a/src/Clients/Goa.Clients.Core/Logging/LogScope.cs b/src/Clients/Goa.Clients.Core/Logging/LogScope.cs
index 9362351e..7808ac2a 100644
--- a/src/Clients/Goa.Clients.Core/Logging/LogScope.cs
+++ b/src/Clients/Goa.Clients.Core/Logging/LogScope.cs
@@ -22,12 +22,14 @@ public LogScope8(
 
     public int Count => 8;
 
-    public KeyValuePair<string, object> this[int index] => index switch
+    public KeyValuePair<string, object> this[int index]
     {
-        0 => _0, 1 => _1, 2 => _2, 3 => _3,
-        4 => _4, 5 => _5, 6 => _6, 7 => _7,
-        _ => throw new IndexOutOfRangeException()
-    };
+        get
+        {
+            if ((uint)index >= 8) Throw.IndexOutOfRange();
+            return index switch { 0 => _0, 1 => _1, 2 => _2, 3 => _3, 4 => _4, 5 => _5, 6 => _6, _ => _7 };
+        }
+    }
 
     public Enumerator GetEnumerator() => new(this);
     IEnumerator<KeyValuePair<string, object>> IEnumerable<KeyValuePair<string, object>>.GetEnumerator() => GetEnumerator();
@@ -48,6 +50,49 @@ public void Dispose() { }
     }
 }
 
+/// <summary>
+/// Zero-allocation log scope with 2 entries. Implements IReadOnlyList so
+/// Microsoft.Extensions.Logging can enumerate properties without a Dictionary allocation.
+/// </summary>
+internal readonly struct LogScope2 : IReadOnlyList<KeyValuePair<string, object>>
+{
+    private readonly KeyValuePair<string, object> _0, _1;
+
+    public LogScope2(KeyValuePair<string, object> p0, KeyValuePair<string, object> p1)
+    {
+        _0 = p0; _1 = p1;
+    }
+
+    public int Count => 2;
+
+    public KeyValuePair<string, object> this[int index]
+    {
+        get
+        {
+            if ((uint)index >= 2) Throw.IndexOutOfRange();
+            return index switch { 0 => _0, _ => _1 };
+        }
+    }
+
+    public Enumerator GetEnumerator() => new(this);
+    IEnumerator<KeyValuePair<string, object>> IEnumerable<KeyValuePair<string, object>>.GetEnumerator() => GetEnumerator();
+    IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
+
+    public struct Enumerator : IEnumerator<KeyValuePair<string, object>>
+    {
+        private readonly LogScope2 _scope;
+        private int _index;
+
+        internal Enumerator(LogScope2 scope) { _scope = scope; _index = -1; }
+
+        public KeyValuePair<string, object> Current => _scope[_index];
+        object IEnumerator.Current => Current;
+        public bool MoveNext() => ++_index < 2;
+        public void Reset() => _index = -1;
+        public void Dispose() { }
+    }
+}
+
 /// <summary>
 /// Zero-allocation log scope with up to 4 entries. Implements IReadOnlyList so
 /// Microsoft.Extensions.Logging can enumerate properties without a Dictionary allocation.
@@ -82,12 +127,14 @@ public LogScope4(
 
     public int Count => _count;
 
-    public KeyValuePair<string, object> this[int index] =>
-        index < _count ? index switch
+    public KeyValuePair<string, object> this[int index]
+    {
+        get
         {
-            0 => _0, 1 => _1, 2 => _2, 3 => _3,
-            _ => throw new IndexOutOfRangeException()
-        } : throw new IndexOutOfRangeException();
+            if ((uint)index >= (uint)_count) Throw.IndexOutOfRange();
+            return index switch { 0 => _0, 1 => _1, 2 => _2, _ => _3 };
+        }
+    }
 
     public Enumerator GetEnumerator() => new(this);
     IEnumerator<KeyValuePair<string, object>> IEnumerable<KeyValuePair<string, object>>.GetEnumerator() => GetEnumerator();
diff --git a/src/Clients/Goa.Clients.Core/Throw.cs b/src/Clients/Goa.Clients.Core/Throw.cs
new file mode 100644
index 00000000..5dbaaa30
--- /dev/null
+++ b/src/Clients/Goa.Clients.Core/Throw.cs
@@ -0,0 +1,31 @@
+using System.Diagnostics.CodeAnalysis;
+using System.Text.Json;
+
+namespace Goa.Clients.Core;
+
+/// <summary>
+/// Shared throw helpers annotated with <see cref="DoesNotReturnAttribute"/> so the JIT
+/// keeps throw-site code out of the inlined hot path.
+/// </summary>
+public static class Throw
+{
+    /// <summary>Throws <see cref="IndexOutOfRangeException"/>.</summary>
+    [DoesNotReturn]
+    public static void IndexOutOfRange() => throw new IndexOutOfRangeException();
+
+    /// <summary>Throws <see cref="InvalidOperationException"/> with the specified message.</summary>
+    [DoesNotReturn]
+    public static void InvalidOperation(string message) => throw new InvalidOperationException(message);
+
+    /// <summary>Throws <see cref="ArgumentNullException"/> for the specified parameter.</summary>
+    [DoesNotReturn]
+    public static void ArgumentNull(string paramName) => throw new ArgumentNullException(paramName);
+
+    /// <summary>Throws <see cref="InvalidOperationException"/>. Returns <typeparamref name="T"/> for use in switch expression arms.</summary>
+    [DoesNotReturn]
+    public static T InvalidOperation<T>(string message) => throw new InvalidOperationException(message);
+
+    /// <summary>Throws <see cref="JsonException"/>. Returns <typeparamref name="T"/> for use in switch expression arms.</summary>
+    [DoesNotReturn]
+    public static T JsonException<T>(string message) => throw new JsonException(message);
+}
diff --git a/src/Clients/Goa.Clients.Core/XmlApiError.cs b/src/Clients/Goa.Clients.Core/XmlApiError.cs
index f6c94613..3ffd2752 100644
--- a/src/Clients/Goa.Clients.Core/XmlApiError.cs
+++ b/src/Clients/Goa.Clients.Core/XmlApiError.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Core;
 /// <summary>
 /// Represents an XML API error response from AWS services, extending the base ApiError with XML deserialization capabilities.
 /// </summary>
-public class XmlApiError : IDeserializeFromXml
+public sealed class XmlApiError : IDeserializeFromXml
 {
     /// <summary>
     /// Gets or sets the AWS request ID associated with this error.
diff --git a/src/Clients/Goa.Clients.Core/XmlAwsServiceClient.cs b/src/Clients/Goa.Clients.Core/XmlAwsServiceClient.cs
index 6ed782f6..b7c22940 100644
--- a/src/Clients/Goa.Clients.Core/XmlAwsServiceClient.cs
+++ b/src/Clients/Goa.Clients.Core/XmlAwsServiceClient.cs
@@ -15,6 +15,7 @@ namespace Goa.Clients.Core;
 /// <typeparam name="T">The configuration type that extends AwsServiceConfiguration.</typeparam>
 public abstract class XmlAwsServiceClient<T> : AwsServiceClient<T> where T : AwsServiceConfiguration
 {
+    private static readonly MediaTypeHeaderValue XmlContentType = new("application/xml");
     private readonly ApiError _deserializationError = new("Failed to deserialize response", "DeserializationError");
 
     /// <summary>
@@ -57,29 +58,28 @@ protected async Task<ApiResponse<TResponse>> SendAsync<TRequest, TResponse>(Http
             }
         }
 
-        using var requestMessage = CreateRequestMessage(method, requestUri + $"?Action={UrlEncoder.Default.Encode(target)}", content, new MediaTypeHeaderValue("application/xml"), headers);
+        using var requestMessage = CreateRequestMessage(method, requestUri + $"?Action={UrlEncoder.Default.Encode(target)}", content, XmlContentType, headers);
         using var response = await SendAsync(requestMessage, target, cancellationToken);
 
-        return await ProcessXmlResponseAsync<TResponse>(response);
+        return await ProcessXmlResponseAsync<TResponse>(response, cancellationToken);
     }
 
     /// <summary>
     /// Processes an HTTP response and converts it to an API response with XML deserialization.
     /// </summary>
-    private async Task<ApiResponse<TResponse>> ProcessXmlResponseAsync<TResponse>(HttpResponseMessage response)
+    private async Task<ApiResponse<TResponse>> ProcessXmlResponseAsync<TResponse>(HttpResponseMessage response, CancellationToken cancellationToken)
         where TResponse : class, IDeserializeFromXml, new()
     {
-        var headers = ResponseHeaders.FromHttpResponse(response.Headers);
-
         if (!response.IsSuccessStatusCode)
         {
-            var errorPayload = await response.Content.ReadAsStringAsync();
-            if (string.IsNullOrWhiteSpace(errorPayload))
+            using var errorBuffer = await ReadResponseBytesAsync(response, cancellationToken);
+            if (errorBuffer.Length == 0)
             {
                 Logger.RequestFailed("No payload present");
                 return new ApiResponse<TResponse>(new ApiError("Request not successful.") { StatusCode = response.StatusCode });
             }
 
+            var errorPayload = Encoding.UTF8.GetString(errorBuffer.Span);
             var error = DeserializeXmlError(errorPayload);
             if (error is not null)
             {
@@ -101,53 +101,24 @@ private async Task<ApiResponse<TResponse>> ProcessXmlResponseAsync<TResponse>(Ht
             return new ApiResponse<TResponse>(error ?? _deserializationError);
         }
 
-        var contentPayload = await response.Content.ReadAsStringAsync();
+        using var pooledBuffer = await ReadResponseBytesAsync(response, cancellationToken);
+        var contentPayload = pooledBuffer.Length > 0 ? Encoding.UTF8.GetString(pooledBuffer.Span) : string.Empty;
         Debug.WriteLine("RESPONSE: " + contentPayload);
 
         // Handle string responses specially
         if (typeof(TResponse) == typeof(string))
         {
-            return new ApiResponse<TResponse>(contentPayload as TResponse, headers);
+            return new ApiResponse<TResponse>(contentPayload as TResponse);
         }
 
         if (string.IsNullOrWhiteSpace(contentPayload))
         {
-            return new ApiResponse<TResponse>(default(TResponse), headers);
+            return new ApiResponse<TResponse>(default(TResponse));
         }
 
         var result = new TResponse();
         result.DeserializeFromXml(contentPayload);
-        return new ApiResponse<TResponse>(result, headers);
-    }
-
-    /// <summary>
-    /// Applies AWS-specific error header processing to the error object.
-    /// </summary>
-    private ApiError ProcessAwsErrorHeaders(HttpResponseMessage response, ApiError error)
-    {
-        if (response.Headers.TryGetValues(XAmznErrorMessage, out var messages))
-        {
-            error = error with { Message = string.Join(", ", messages) };
-        }
-
-        if (string.IsNullOrWhiteSpace(error.Type) && response.Headers.TryGetValues(XAmzErrorType, out var types))
-        {
-            error = error with { Type = string.Join(", ", types) };
-        }
-
-        var infoSeparator = error.Type?.LastIndexOf(':') ?? -1;
-        if (infoSeparator > 0)
-        {
-            error = error with { Type = error.Type![..infoSeparator] };
-        }
-
-        var typeSeparator = error.Type?.LastIndexOf('#') ?? -1;
-        if (typeSeparator > 0)
-        {
-            error = error with { Type = error.Type![(typeSeparator + 1)..] };
-        }
-
-        return error;
+        return new ApiResponse<TResponse>(result);
     }
 
     /// <summary>
@@ -179,7 +150,9 @@ private static byte[] SerializeToXmlBytes(object request)
         }
         catch (Exception ex)
         {
+#pragma warning disable GOA1001 // Error-handling path: params allocation is acceptable here
             Logger.LogWarning(ex, "Failed to deserialize XML error response: {Content}", content);
+#pragma warning restore GOA1001
             return null;
         }
     }
@@ -189,6 +162,6 @@ private static byte[] SerializeToXmlBytes(object request)
     /// </summary>
     private static bool IsXmlSerialized(string input)
     {
-        return input.TrimStart().StartsWith('<');
+        return input.AsSpan().TrimStart().StartsWith("<");
     }
 }
\ No newline at end of file
diff --git a/src/Clients/Goa.Clients.Dynamo.Generator/CodeGeneration/JsonMapperGenerator.cs b/src/Clients/Goa.Clients.Dynamo.Generator/CodeGeneration/JsonMapperGenerator.cs
index a44966d1..a1c533f1 100644
--- a/src/Clients/Goa.Clients.Dynamo.Generator/CodeGeneration/JsonMapperGenerator.cs
+++ b/src/Clients/Goa.Clients.Dynamo.Generator/CodeGeneration/JsonMapperGenerator.cs
@@ -32,6 +32,7 @@ public string GenerateCode(IEnumerable<DynamoTypeInfo> types, GenerationContext
         builder.AppendLine("using System.Collections.Generic;");
         builder.AppendLine("using System.Globalization;");
         builder.AppendLine("using System.Text.Json;");
+        builder.AppendLine("using Goa.Clients.Core;");
 
         foreach (var ns in typesByNamespace)
         {
@@ -113,7 +114,8 @@ private void GenerateAbstractWriteDispatch(CodeBuilder builder, DynamoTypeInfo t
 
         builder.AppendLine("default:");
         builder.Indent();
-        builder.AppendLine($"throw new InvalidOperationException($\"Unknown concrete type: {{model.GetType().FullName}} for abstract type {type.FullName}\");");
+        builder.AppendLine($"Throw.InvalidOperation($\"Unknown concrete type: {{model.GetType().FullName}} for abstract type {type.FullName}\");");
+        builder.AppendLine("return;");
         builder.Unindent();
         builder.CloseBrace();
     }
@@ -527,7 +529,7 @@ private void GenerateAbstractReadDispatch(CodeBuilder builder, DynamoTypeInfo ty
         builder.CloseBrace();
         builder.AppendLine();
         builder.AppendLine($"if (typeDiscriminator == null)");
-        builder.Indent().AppendLine($"throw new InvalidOperationException(\"Missing {typeNameField} discriminator for abstract type {type.FullName}\");").Unindent();
+        builder.Indent().AppendLine($"Throw.InvalidOperation(\"Missing {typeNameField} discriminator for abstract type {type.FullName}\");").Unindent();
         builder.AppendLine();
         builder.OpenBraceWithLine("return typeDiscriminator switch");
 
@@ -540,7 +542,7 @@ private void GenerateAbstractReadDispatch(CodeBuilder builder, DynamoTypeInfo ty
             }
         }
 
-        builder.AppendLine($"_ => throw new InvalidOperationException($\"Unknown type: {{typeDiscriminator}} for abstract type {type.FullName}\")");
+        builder.AppendLine($"_ => Throw.InvalidOperation<{type.FullName}>($\"Unknown type: {{typeDiscriminator}} for abstract type {type.FullName}\")");
         builder.CloseBrace().Append(";");
         builder.AppendLine();
     }
diff --git a/src/Clients/Goa.Clients.Dynamo.Generator/CodeGeneration/MapperGenerator.cs b/src/Clients/Goa.Clients.Dynamo.Generator/CodeGeneration/MapperGenerator.cs
index 3a0487b3..6381b55a 100644
--- a/src/Clients/Goa.Clients.Dynamo.Generator/CodeGeneration/MapperGenerator.cs
+++ b/src/Clients/Goa.Clients.Dynamo.Generator/CodeGeneration/MapperGenerator.cs
@@ -37,6 +37,7 @@ public string GenerateCode(IEnumerable<DynamoTypeInfo> types, GenerationContext
         builder.AppendLine("using Goa.Clients.Dynamo.Models;");
         builder.AppendLine("using Goa.Clients.Dynamo.Exceptions;");
         builder.AppendLine("using Goa.Clients.Dynamo.Extensions;");
+        builder.AppendLine("using Goa.Clients.Core;");
 
         foreach (var ns in typesByNamespace)
         {
@@ -135,7 +136,7 @@ private void GenerateAbstractToDynamoRecordDispatch(CodeBuilder builder, DynamoT
             builder.AppendLine($"{concreteType.FullName} concrete => DynamoMapper.{normalizedTypeName}.ToDynamoRecord(concrete),");
         }
 
-        builder.AppendLine($"_ => throw new InvalidOperationException($\"Unknown concrete type: {{model.GetType().FullName}} for abstract type {type.FullName}\")");
+        builder.AppendLine($"_ => Throw.InvalidOperation<DynamoRecord>($\"Unknown concrete type: {{model.GetType().FullName}} for abstract type {type.FullName}\")");
         builder.CloseBrace().Append(";");
     }
 
@@ -378,7 +379,7 @@ private void GenerateAbstractTypeDispatch(CodeBuilder builder, DynamoTypeInfo ty
         var typeNameField = dynamoModelAttr?.TypeName ?? "Type";
 
         builder.AppendLine($"if (!record.TryGetNullableString(\"{typeNameField}\", out var typeValue) || typeValue == null)");
-        builder.Indent().AppendLine($"throw new InvalidOperationException(\"Missing {typeNameField} discriminator for abstract type {type.FullName}\");").Unindent();
+        builder.Indent().AppendLine($"Throw.InvalidOperation(\"Missing {typeNameField} discriminator for abstract type {type.FullName}\");").Unindent();
         builder.AppendLine();
         builder.OpenBraceWithLine("return typeValue switch");
 
@@ -391,7 +392,7 @@ private void GenerateAbstractTypeDispatch(CodeBuilder builder, DynamoTypeInfo ty
             }
         }
 
-        builder.AppendLine($"_ => throw new InvalidOperationException($\"Unknown type: {{typeValue}} for abstract type {type.FullName}\")");
+        builder.AppendLine($"_ => Throw.InvalidOperation<{type.FullName}>($\"Unknown type: {{typeValue}} for abstract type {type.FullName}\")");
         builder.CloseBrace().Append(";");
     }
 
diff --git a/src/Clients/Goa.Clients.Dynamo.Generator/DynamoMapperIncrementalGenerator.cs b/src/Clients/Goa.Clients.Dynamo.Generator/DynamoMapperIncrementalGenerator.cs
index 1b33432a..68fc6c8b 100644
--- a/src/Clients/Goa.Clients.Dynamo.Generator/DynamoMapperIncrementalGenerator.cs
+++ b/src/Clients/Goa.Clients.Dynamo.Generator/DynamoMapperIncrementalGenerator.cs
@@ -218,9 +218,13 @@ private static void CollectReferencedTypes(INamedTypeSymbol type, HashSet<INamed
         {
             var propertyType = member.Type;
 
-            // Skip system types that shouldn't be analyzed
-            if (IsSystemType(propertyType))
-                continue;
+            // Recursively unwrap collection types (e.g. List<List<MyType>> -> MyType)
+            // before the system type check, so that system collections are resolved
+            // to their innermost element type
+            while (IsCollectionType(propertyType, out var elementType))
+            {
+                propertyType = elementType;
+            }
 
             // Handle nullable types
             if (propertyType is INamedTypeSymbol nullableType && nullableType.IsGenericType)
@@ -228,11 +232,9 @@ private static void CollectReferencedTypes(INamedTypeSymbol type, HashSet<INamed
                 propertyType = nullableType.TypeArguments[0];
             }
 
-            // Handle collection types
-            if (IsCollectionType(propertyType, out var elementType))
-            {
-                propertyType = elementType;
-            }
+            // Skip system types that shouldn't be analyzed
+            if (IsSystemType(propertyType))
+                continue;
 
             // Handle complex types
             if (propertyType is INamedTypeSymbol namedType &&
diff --git a/src/Clients/Goa.Clients.Dynamo/DynamoExtensions.cs b/src/Clients/Goa.Clients.Dynamo/DynamoExtensions.cs
index d244a479..66263dc9 100644
--- a/src/Clients/Goa.Clients.Dynamo/DynamoExtensions.cs
+++ b/src/Clients/Goa.Clients.Dynamo/DynamoExtensions.cs
@@ -163,7 +163,7 @@ public static async IAsyncEnumerable<DynamoRecord> QueryAllAsync(this IDynamoCli
             var result = await client.QueryAsync(request, cancellationToken);
             if (result.IsError)
             {
-                throw new DynamoPaginationException(result.FirstError);
+                DynamoPaginationException.Throw(result.FirstError);
             }
 
             foreach (var item in result.Value.Items)
@@ -200,7 +200,7 @@ public static async IAsyncEnumerable<DynamoRecord> ScanAllAsync(this IDynamoClie
             var result = await client.ScanAsync(request, cancellationToken);
             if (result.IsError)
             {
-                throw new DynamoPaginationException(result.FirstError);
+                DynamoPaginationException.Throw(result.FirstError);
             }
 
             foreach (var item in result.Value.Items)
@@ -232,7 +232,7 @@ public static async IAsyncEnumerable<T> QueryAllAsync<T>(this IDynamoClient clie
             var result = await client.QueryAsync(request, itemReader, cancellationToken);
             if (result.IsError)
             {
-                throw new DynamoPaginationException(result.FirstError);
+                DynamoPaginationException.Throw(result.FirstError);
             }
 
             foreach (var item in result.Value.Items)
@@ -264,7 +264,7 @@ public static async IAsyncEnumerable<T> ScanAllAsync<T>(this IDynamoClient clien
             var result = await client.ScanAsync(request, itemReader, cancellationToken);
             if (result.IsError)
             {
-                throw new DynamoPaginationException(result.FirstError);
+                DynamoPaginationException.Throw(result.FirstError);
             }
 
             foreach (var item in result.Value.Items)
@@ -302,7 +302,7 @@ public static async IAsyncEnumerable<KeyValuePair<string, DynamoRecord>> BatchGe
             var result = await client.BatchGetItemAsync(request, cancellationToken);
             if (result.IsError)
             {
-                throw new DynamoPaginationException(result.FirstError);
+                DynamoPaginationException.Throw(result.FirstError);
             }
 
             foreach (var tableResponse in result.Value.Responses)
@@ -320,7 +320,7 @@ public static async IAsyncEnumerable<KeyValuePair<string, DynamoRecord>> BatchGe
 
             if (attempts >= maxAttempts)
             {
-                throw new DynamoPaginationException(
+                DynamoPaginationException.Throw(
                     ErrorOr.Error.Failure("Goa.DynamoDb.MaxRetriesExceeded", $"BatchGetItem still has unprocessed keys after {maxAttempts} retry attempts."));
             }
 
@@ -350,7 +350,7 @@ public static async IAsyncEnumerable<KeyValuePair<string, T>> BatchGetAllAsync<T
             var result = await client.BatchGetItemAsync(request, itemReader, cancellationToken);
             if (result.IsError)
             {
-                throw new DynamoPaginationException(result.FirstError);
+                DynamoPaginationException.Throw(result.FirstError);
             }
 
             foreach (var tableResponse in result.Value.Responses)
@@ -368,7 +368,7 @@ public static async IAsyncEnumerable<KeyValuePair<string, T>> BatchGetAllAsync<T
 
             if (attempts >= maxAttempts)
             {
-                throw new DynamoPaginationException(
+                DynamoPaginationException.Throw(
                     ErrorOr.Error.Failure("Goa.DynamoDb.MaxRetriesExceeded", $"BatchGetItem still has unprocessed keys after {maxAttempts} retry attempts."));
             }
 
diff --git a/src/Clients/Goa.Clients.Dynamo/DynamoModelAttribute.cs b/src/Clients/Goa.Clients.Dynamo/DynamoModelAttribute.cs
index 6d98a01f..d39b5ece 100644
--- a/src/Clients/Goa.Clients.Dynamo/DynamoModelAttribute.cs
+++ b/src/Clients/Goa.Clients.Dynamo/DynamoModelAttribute.cs
@@ -5,7 +5,7 @@
 /// This attribute is inherited, allowing base classes to define common PK/SK patterns.
 /// </summary>
 [AttributeUsage(AttributeTargets.Class, AllowMultiple = false, Inherited = true)]
-public class DynamoModelAttribute : Attribute
+public sealed class DynamoModelAttribute : Attribute
 {
     /// <summary>
     /// The partition key pattern. Supports placeholders like "ENTITY#&lt;PropertyName&gt;" 
diff --git a/src/Clients/Goa.Clients.Dynamo/DynamoServiceClient.cs b/src/Clients/Goa.Clients.Dynamo/DynamoServiceClient.cs
index 2db6b367..f5aaae78 100644
--- a/src/Clients/Goa.Clients.Dynamo/DynamoServiceClient.cs
+++ b/src/Clients/Goa.Clients.Dynamo/DynamoServiceClient.cs
@@ -21,7 +21,7 @@ namespace Goa.Clients.Dynamo;
 /// High-performance DynamoDB service client that implements IDynamoClient using AWS service client infrastructure.
 /// Provides strongly-typed DynamoDB operations with built-in error handling, logging, and AWS authentication.
 /// </summary>
-public class DynamoServiceClient : JsonAwsServiceClient<DynamoServiceClientConfiguration>, IDynamoClient
+public sealed class DynamoServiceClient : JsonAwsServiceClient<DynamoServiceClientConfiguration>, IDynamoClient
 {
     /// <summary>
     /// Initializes a new instance of the DynamoServiceClient class.
@@ -366,7 +366,9 @@ private async Task<Error> HandleTypedErrorAsync(HttpResponseMessage response, Ca
         var metadata = new Dictionary<string, object>
         {
             ["Payload"] = errorPayload,
+#pragma warning disable GOA1501 // Boxing unavoidable with Dictionary<string, object> on error path
             ["StatusCode"] = response.StatusCode
+#pragma warning restore GOA1501
         };
         return Error.Failure(
             code: MapErrorCodeToDynamo(errorType),
diff --git a/src/Clients/Goa.Clients.Dynamo/DynamoServiceClientConfiguration.cs b/src/Clients/Goa.Clients.Dynamo/DynamoServiceClientConfiguration.cs
index 245d69ce..14853898 100644
--- a/src/Clients/Goa.Clients.Dynamo/DynamoServiceClientConfiguration.cs
+++ b/src/Clients/Goa.Clients.Dynamo/DynamoServiceClientConfiguration.cs
@@ -5,7 +5,7 @@ namespace Goa.Clients.Dynamo;
 /// <summary>
 /// Configuration class for DynamoDB service providing DynamoDB-specific settings.
 /// </summary>
-public class DynamoServiceClientConfiguration : AwsServiceConfiguration
+public sealed class DynamoServiceClientConfiguration : AwsServiceConfiguration
 {
     /// <summary>
     /// Initializes a new instance of the DynamoServiceClientConfiguration class.
diff --git a/src/Clients/Goa.Clients.Dynamo/Errors/ErrorExtensions.cs b/src/Clients/Goa.Clients.Dynamo/Errors/ErrorExtensions.cs
index 6625920c..1a7064ac 100644
--- a/src/Clients/Goa.Clients.Dynamo/Errors/ErrorExtensions.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Errors/ErrorExtensions.cs
@@ -16,7 +16,12 @@ public static class ErrorExtensions
     public static bool IsDynamoError<T>(this ErrorOr<T> errorOr)
     {
         if (!errorOr.IsError) return false;
-        return errorOr.Errors.Any(e => e.Code.StartsWith("Goa.DynamoDb.", StringComparison.Ordinal));
+        foreach (var e in errorOr.Errors)
+        {
+            if (e.Code.StartsWith("Goa.DynamoDb.", StringComparison.Ordinal))
+                return true;
+        }
+        return false;
     }
 
     /// <summary>
@@ -28,13 +33,17 @@ public static bool IsDynamoError<T>(this ErrorOr<T> errorOr)
     public static bool IsDynamoConcurrencyError<T>(this ErrorOr<T> errorOr)
     {
         if (!errorOr.IsError) return false;
-        return errorOr.Errors.Any(e =>
-            e.Code == DynamoErrorCodes.ConditionalCheckFailedException ||
-            e.Code == DynamoErrorCodes.ConditionalCheckFailed ||
-            e.Code == DynamoErrorCodes.TransactionConflictException ||
-            e.Code == DynamoErrorCodes.TransactionConflict ||
-            e.Code == DynamoErrorCodes.ReplicatedWriteConflictException ||
-            (e.Code == DynamoErrorCodes.ValidationException && e.Description.Contains("condition", StringComparison.OrdinalIgnoreCase)));
+        foreach (var e in errorOr.Errors)
+        {
+            if (e.Code == DynamoErrorCodes.ConditionalCheckFailedException ||
+                e.Code == DynamoErrorCodes.ConditionalCheckFailed ||
+                e.Code == DynamoErrorCodes.TransactionConflictException ||
+                e.Code == DynamoErrorCodes.TransactionConflict ||
+                e.Code == DynamoErrorCodes.ReplicatedWriteConflictException ||
+                (e.Code == DynamoErrorCodes.ValidationException && e.Description.Contains("condition", StringComparison.OrdinalIgnoreCase)))
+                return true;
+        }
+        return false;
     }
 
     /// <summary>
@@ -46,15 +55,19 @@ public static bool IsDynamoConcurrencyError<T>(this ErrorOr<T> errorOr)
     public static bool IsDynamoItemNotFoundError<T>(this ErrorOr<T> errorOr)
     {
         if (!errorOr.IsError) return false;
-        return errorOr.Errors.Any(e =>
-            e.Code == DynamoErrorCodes.ResourceNotFoundException ||
-            e.Code == DynamoErrorCodes.ItemNotFound ||
-            e.Code == DynamoErrorCodes.NotFound ||
-            e.Code == DynamoErrorCodes.TableNotFoundException ||
-            e.Code == DynamoErrorCodes.TableNotFound ||
-            e.Code == DynamoErrorCodes.IndexNotFoundException ||
-            e.Code == DynamoErrorCodes.IndexNotFound ||
-            e.Type == ErrorType.NotFound);
+        foreach (var e in errorOr.Errors)
+        {
+            if (e.Code == DynamoErrorCodes.ResourceNotFoundException ||
+                e.Code == DynamoErrorCodes.ItemNotFound ||
+                e.Code == DynamoErrorCodes.NotFound ||
+                e.Code == DynamoErrorCodes.TableNotFoundException ||
+                e.Code == DynamoErrorCodes.TableNotFound ||
+                e.Code == DynamoErrorCodes.IndexNotFoundException ||
+                e.Code == DynamoErrorCodes.IndexNotFound ||
+                e.Type == ErrorType.NotFound)
+                return true;
+        }
+        return false;
     }
 
     /// <summary>
@@ -66,13 +79,17 @@ public static bool IsDynamoItemNotFoundError<T>(this ErrorOr<T> errorOr)
     public static bool IsDynamoThrottlingError<T>(this ErrorOr<T> errorOr)
     {
         if (!errorOr.IsError) return false;
-        return errorOr.Errors.Any(e =>
-            e.Code == DynamoErrorCodes.ProvisionedThroughputExceededException ||
-            e.Code == DynamoErrorCodes.ProvisionedThroughputExceeded ||
-            e.Code == DynamoErrorCodes.RequestLimitExceeded ||
-            e.Code == DynamoErrorCodes.ThrottlingException ||
-            e.Code == DynamoErrorCodes.TooManyRequestsException ||
-            e.Code == DynamoErrorCodes.TooManyRequests);
+        foreach (var e in errorOr.Errors)
+        {
+            if (e.Code == DynamoErrorCodes.ProvisionedThroughputExceededException ||
+                e.Code == DynamoErrorCodes.ProvisionedThroughputExceeded ||
+                e.Code == DynamoErrorCodes.RequestLimitExceeded ||
+                e.Code == DynamoErrorCodes.ThrottlingException ||
+                e.Code == DynamoErrorCodes.TooManyRequestsException ||
+                e.Code == DynamoErrorCodes.TooManyRequests)
+                return true;
+        }
+        return false;
     }
 
     /// <summary>
@@ -84,13 +101,17 @@ public static bool IsDynamoThrottlingError<T>(this ErrorOr<T> errorOr)
     public static bool IsDynamoValidationError<T>(this ErrorOr<T> errorOr)
     {
         if (!errorOr.IsError) return false;
-        return errorOr.Errors.Any(e =>
-            e.Code == DynamoErrorCodes.ValidationException ||
-            e.Code == DynamoErrorCodes.InvalidParameterValueException ||
-            e.Code == DynamoErrorCodes.InvalidParameterValue ||
-            e.Code == DynamoErrorCodes.MissingParameterException ||
-            e.Code == DynamoErrorCodes.MissingParameter ||
-            e.Type == ErrorType.Validation);
+        foreach (var e in errorOr.Errors)
+        {
+            if (e.Code == DynamoErrorCodes.ValidationException ||
+                e.Code == DynamoErrorCodes.InvalidParameterValueException ||
+                e.Code == DynamoErrorCodes.InvalidParameterValue ||
+                e.Code == DynamoErrorCodes.MissingParameterException ||
+                e.Code == DynamoErrorCodes.MissingParameter ||
+                e.Type == ErrorType.Validation)
+                return true;
+        }
+        return false;
     }
 
     /// <summary>
@@ -102,16 +123,20 @@ public static bool IsDynamoValidationError<T>(this ErrorOr<T> errorOr)
     public static bool IsDynamoAuthError<T>(this ErrorOr<T> errorOr)
     {
         if (!errorOr.IsError) return false;
-        return errorOr.Errors.Any(e =>
-            e.Code == DynamoErrorCodes.UnauthorizedException ||
-            e.Code == DynamoErrorCodes.Unauthorized ||
-            e.Code == DynamoErrorCodes.AccessDeniedException ||
-            e.Code == DynamoErrorCodes.AccessDenied ||
-            e.Code == DynamoErrorCodes.InvalidUserPoolConfigurationException ||
-            e.Code == DynamoErrorCodes.InvalidUserPoolConfiguration ||
-            e.Code == DynamoErrorCodes.NotAuthorizedException ||
-            e.Code == DynamoErrorCodes.NotAuthorized ||
-            e.Type == ErrorType.Unauthorized);
+        foreach (var e in errorOr.Errors)
+        {
+            if (e.Code == DynamoErrorCodes.UnauthorizedException ||
+                e.Code == DynamoErrorCodes.Unauthorized ||
+                e.Code == DynamoErrorCodes.AccessDeniedException ||
+                e.Code == DynamoErrorCodes.AccessDenied ||
+                e.Code == DynamoErrorCodes.InvalidUserPoolConfigurationException ||
+                e.Code == DynamoErrorCodes.InvalidUserPoolConfiguration ||
+                e.Code == DynamoErrorCodes.NotAuthorizedException ||
+                e.Code == DynamoErrorCodes.NotAuthorized ||
+                e.Type == ErrorType.Unauthorized)
+                return true;
+        }
+        return false;
     }
 
     /// <summary>
@@ -123,13 +148,18 @@ public static bool IsDynamoAuthError<T>(this ErrorOr<T> errorOr)
     public static bool IsDynamoRetryableError<T>(this ErrorOr<T> errorOr)
     {
         if (!errorOr.IsError) return false;
-        return errorOr.IsDynamoThrottlingError() ||
-               errorOr.Errors.Any(e =>
-                   e.Code == DynamoErrorCodes.InternalServerError ||
-                   e.Code == DynamoErrorCodes.ServiceUnavailable ||
-                   e.Code == DynamoErrorCodes.RequestTimeoutException ||
-                   e.Code == DynamoErrorCodes.RequestTimeout ||
-                   (e.Type == ErrorType.Failure && !e.Description.Contains("permanent", StringComparison.OrdinalIgnoreCase)));
+        if (errorOr.IsDynamoThrottlingError())
+            return true;
+        foreach (var e in errorOr.Errors)
+        {
+            if (e.Code == DynamoErrorCodes.InternalServerError ||
+                e.Code == DynamoErrorCodes.ServiceUnavailable ||
+                e.Code == DynamoErrorCodes.RequestTimeoutException ||
+                e.Code == DynamoErrorCodes.RequestTimeout ||
+                (e.Type == ErrorType.Failure && !e.Description.Contains("permanent", StringComparison.OrdinalIgnoreCase)))
+                return true;
+        }
+        return false;
     }
 
     /// <summary>
@@ -141,9 +171,13 @@ public static bool IsDynamoRetryableError<T>(this ErrorOr<T> errorOr)
     public static bool IsDynamoResourceStateError<T>(this ErrorOr<T> errorOr)
     {
         if (!errorOr.IsError) return false;
-        return errorOr.Errors.Any(e =>
-            e.Code == DynamoErrorCodes.ResourceInUseException ||
-            e.Code == DynamoErrorCodes.ResourceInUse);
+        foreach (var e in errorOr.Errors)
+        {
+            if (e.Code == DynamoErrorCodes.ResourceInUseException ||
+                e.Code == DynamoErrorCodes.ResourceInUse)
+                return true;
+        }
+        return false;
     }
 
     /// <summary>
diff --git a/src/Clients/Goa.Clients.Dynamo/Exceptions/DynamoPaginationException.cs b/src/Clients/Goa.Clients.Dynamo/Exceptions/DynamoPaginationException.cs
index df5f8255..0b3c28a6 100644
--- a/src/Clients/Goa.Clients.Dynamo/Exceptions/DynamoPaginationException.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Exceptions/DynamoPaginationException.cs
@@ -1,3 +1,4 @@
+using System.Diagnostics.CodeAnalysis;
 using ErrorOr;
 
 namespace Goa.Clients.Dynamo.Exceptions;
@@ -6,7 +7,7 @@ namespace Goa.Clients.Dynamo.Exceptions;
 /// Exception thrown when an auto-pagination operation encounters an error during a page request.
 /// This prevents silent truncation of results in methods like QueryAllAsync, ScanAllAsync, and BatchGetAllAsync.
 /// </summary>
-public class DynamoPaginationException : Exception
+public sealed class DynamoPaginationException : Exception
 {
     /// <summary>
     /// Gets the underlying error that caused the pagination failure.
@@ -33,4 +34,7 @@ public DynamoPaginationException(Error error, Exception innerException)
     {
         Error = error;
     }
+
+    [DoesNotReturn]
+    internal static void Throw(Error error) => throw new DynamoPaginationException(error);
 }
diff --git a/src/Clients/Goa.Clients.Dynamo/Exceptions/MissingAttributeException.cs b/src/Clients/Goa.Clients.Dynamo/Exceptions/MissingAttributeException.cs
index 5362fb2a..9d641d89 100644
--- a/src/Clients/Goa.Clients.Dynamo/Exceptions/MissingAttributeException.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Exceptions/MissingAttributeException.cs
@@ -1,9 +1,11 @@
+using System.Diagnostics.CodeAnalysis;
+
 namespace Goa.Clients.Dynamo.Exceptions;
 
 /// <summary>
 /// Exception thrown when a required DynamoDB attribute is missing or null.
 /// </summary>
-public class MissingAttributeException : Exception
+public sealed class MissingAttributeException : Exception
 {
     /// <summary>
     /// Gets the name of the missing attribute.
@@ -70,6 +72,8 @@ public MissingAttributeException(string attributeName, Exception innerException,
     /// <param name="attributeName">The name of the missing attribute.</param>
     /// <returns>Never returns (always throws).</returns>
     /// <exception cref="MissingAttributeException">Always thrown.</exception>
+    [DoesNotReturn]
+
     public static T Throw<T>(string attributeName)
     {
         throw new MissingAttributeException(attributeName);
@@ -83,6 +87,8 @@ public static T Throw<T>(string attributeName)
     /// <param name="sortKey">The sort key value for context.</param>
     /// <returns>Never returns (always throws).</returns>
     /// <exception cref="MissingAttributeException">Always thrown.</exception>
+    [DoesNotReturn]
+
     public static T Throw<T>(string attributeName, string? partitionKey, string? sortKey)
     {
         throw new MissingAttributeException(attributeName, partitionKey, sortKey);
@@ -94,6 +100,8 @@ public static T Throw<T>(string attributeName, string? partitionKey, string? sor
     /// </summary>
     /// <param name="attributeName">The name of the missing attribute.</param>
     /// <exception cref="MissingAttributeException">Always thrown.</exception>
+    [DoesNotReturn]
+
     public static void Throw(string attributeName)
     {
         throw new MissingAttributeException(attributeName);
@@ -107,6 +115,8 @@ public static void Throw(string attributeName)
     /// <param name="partitionKey">The partition key value for context.</param>
     /// <param name="sortKey">The sort key value for context.</param>
     /// <exception cref="MissingAttributeException">Always thrown.</exception>
+    [DoesNotReturn]
+
     public static void Throw(string attributeName, string? partitionKey, string? sortKey)
     {
         throw new MissingAttributeException(attributeName, partitionKey, sortKey);
diff --git a/src/Clients/Goa.Clients.Dynamo/ExtensionAttribute.cs b/src/Clients/Goa.Clients.Dynamo/ExtensionAttribute.cs
index 393821f7..2d7d43fe 100644
--- a/src/Clients/Goa.Clients.Dynamo/ExtensionAttribute.cs
+++ b/src/Clients/Goa.Clients.Dynamo/ExtensionAttribute.cs
@@ -11,6 +11,6 @@ namespace Goa.Clients.Dynamo;
 /// in your project file.
 /// </remarks>
 [AttributeUsage(AttributeTargets.Class, AllowMultiple = false, Inherited = false)]
-public class ExtensionAttribute : Attribute
+public sealed class ExtensionAttribute : Attribute
 {
 }
diff --git a/src/Clients/Goa.Clients.Dynamo/Extensions/DynamoRecordExtensions.cs b/src/Clients/Goa.Clients.Dynamo/Extensions/DynamoRecordExtensions.cs
index 7202c357..54a86d07 100644
--- a/src/Clients/Goa.Clients.Dynamo/Extensions/DynamoRecordExtensions.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Extensions/DynamoRecordExtensions.cs
@@ -541,9 +541,11 @@ public static bool TryGetIntSet(this DynamoRecord record, string columnName, out
         if (attributeValue.NS == null)
             return false;
 
-        value = attributeValue.NS.Select(x => int.TryParse(x, out var val) ? val : (int?)null)
-                                  .Where(x => x.HasValue)
-                                  .Select(x => x!.Value);
+        var result = new List<int>();
+        foreach (var x in attributeValue.NS)
+            if (int.TryParse(x, out var val))
+                result.Add(val);
+        value = result;
         return true;
     }
 
@@ -569,9 +571,11 @@ public static bool TryGetLongSet(this DynamoRecord record, string columnName, ou
         if (attributeValue.NS == null)
             return false;
 
-        value = attributeValue.NS.Select(x => long.TryParse(x, out var val) ? val : (long?)null)
-                                  .Where(x => x.HasValue)
-                                  .Select(x => x!.Value);
+        var result = new List<long>();
+        foreach (var x in attributeValue.NS)
+            if (long.TryParse(x, out var val))
+                result.Add(val);
+        value = result;
         return true;
     }
 
@@ -597,9 +601,11 @@ public static bool TryGetDoubleSet(this DynamoRecord record, string columnName,
         if (attributeValue.NS == null)
             return false;
 
-        value = attributeValue.NS.Select(x => double.TryParse(x, out var val) ? val : (double?)null)
-                                  .Where(x => x.HasValue)
-                                  .Select(x => x!.Value);
+        var result = new List<double>();
+        foreach (var x in attributeValue.NS)
+            if (double.TryParse(x, out var val))
+                result.Add(val);
+        value = result;
         return true;
     }
 
@@ -626,9 +632,13 @@ public static bool TryGetEnumSet<T>(this DynamoRecord record, string columnName,
         if (attributeValue.SS == null)
             return false;
 
-        value = attributeValue.SS.Select(x => Enum.TryParse<T>(x, out var val) ? val : (T?)null)
-                                  .Where(x => x.HasValue)
-                                  .Select(x => x!.Value);
+        var result = new List<T>();
+        foreach (var x in attributeValue.SS)
+        {
+            if (Enum.TryParse<T>(x, out var val))
+                result.Add(val);
+        }
+        value = result;
         return true;
     }
 
@@ -1046,9 +1056,11 @@ public static bool TryGetDateTimeSet(this DynamoRecord record, string columnName
         if (attributeValue.SS == null)
             return false;
 
-        value = attributeValue.SS.Select(x => DateTime.TryParse(x, out var val) ? val : (DateTime?)null)
-                                  .Where(x => x.HasValue)
-                                  .Select(x => x!.Value);
+        var result = new List<DateTime>();
+        foreach (var x in attributeValue.SS)
+            if (DateTime.TryParse(x, out var val))
+                result.Add(val);
+        value = result;
         return true;
     }
 
diff --git a/src/Clients/Goa.Clients.Dynamo/GlobalSecondaryIndexAttribute.cs b/src/Clients/Goa.Clients.Dynamo/GlobalSecondaryIndexAttribute.cs
index 9d58ea37..fe9e001d 100644
--- a/src/Clients/Goa.Clients.Dynamo/GlobalSecondaryIndexAttribute.cs
+++ b/src/Clients/Goa.Clients.Dynamo/GlobalSecondaryIndexAttribute.cs
@@ -5,7 +5,7 @@
 /// This attribute is inherited, allowing base classes to define common GSI patterns.
 /// </summary>
 [AttributeUsage(AttributeTargets.Class, AllowMultiple = true, Inherited = true)]
-public class GlobalSecondaryIndexAttribute : Attribute
+public sealed class GlobalSecondaryIndexAttribute : Attribute
 {
     /// <summary>
     /// The name of the Global Secondary Index in DynamoDB.
diff --git a/src/Clients/Goa.Clients.Dynamo/IgnoreAttribute.cs b/src/Clients/Goa.Clients.Dynamo/IgnoreAttribute.cs
index d5bfc056..fbedefad 100644
--- a/src/Clients/Goa.Clients.Dynamo/IgnoreAttribute.cs
+++ b/src/Clients/Goa.Clients.Dynamo/IgnoreAttribute.cs
@@ -5,7 +5,7 @@ namespace Goa.Clients.Dynamo;
 /// By default, ignores the property in both directions (reading and writing).
 /// </summary>
 [AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
-public class IgnoreAttribute : Attribute
+public sealed class IgnoreAttribute : Attribute
 {
     /// <summary>
     /// The direction in which to ignore the property. Defaults to Always.
diff --git a/src/Clients/Goa.Clients.Dynamo/Internal/DynamoResponseReader.cs b/src/Clients/Goa.Clients.Dynamo/Internal/DynamoResponseReader.cs
index f5ab7b83..78cf8d56 100644
--- a/src/Clients/Goa.Clients.Dynamo/Internal/DynamoResponseReader.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Internal/DynamoResponseReader.cs
@@ -1,6 +1,7 @@
 using System.Text.Json;
 using Goa.Clients.Dynamo.Models;
 using Goa.Clients.Dynamo.Operations.Batch;
+using Goa.Clients.Dynamo.Operations.GetItem;
 using Goa.Clients.Dynamo.Operations.Query;
 using Goa.Clients.Dynamo.Operations.Scan;
 using Goa.Clients.Dynamo.Operations.Transactions;
@@ -161,6 +162,228 @@ internal static DynamoRecord ReadDynamoRecordItemCached(ref Utf8JsonReader reade
         return record;
     }
 
+    internal static QueryResponse ReadDynamoRecordQueryResponse(ref Utf8JsonReader reader)
+    {
+        var cache = new PropertyNameCache();
+        var result = new QueryResponse();
+
+        reader.Read(); // StartObject
+        while (reader.Read() && reader.TokenType == JsonTokenType.PropertyName)
+        {
+            if (reader.ValueTextEquals("Items"u8))
+            {
+                reader.Read();
+                result.Items = ReadDynamoRecordItems(ref reader, ref cache);
+            }
+            else if (reader.ValueTextEquals("Count"u8))
+            {
+                reader.Read();
+                // DynamoDB Count always equals Items.Count (post-filter); ScannedCount is the pre-filter total
+                reader.GetInt32();
+            }
+            else if (reader.ValueTextEquals("ScannedCount"u8))
+            {
+                reader.Read();
+                result.ScannedCount = reader.GetInt32();
+            }
+            else if (reader.ValueTextEquals("LastEvaluatedKey"u8))
+            {
+                reader.Read();
+                result.LastEvaluatedKey = ReadAttributeMap(ref reader);
+            }
+            else if (reader.ValueTextEquals("ConsumedCapacity"u8))
+            {
+                reader.Read();
+                result.ConsumedCapacity = ReadConsumedCapacity(ref reader);
+            }
+            else
+            {
+                reader.Read();
+                reader.Skip();
+            }
+        }
+
+        return result;
+    }
+
+    internal static ScanResponse ReadDynamoRecordScanResponse(ref Utf8JsonReader reader)
+    {
+        var cache = new PropertyNameCache();
+        var result = new ScanResponse();
+
+        reader.Read(); // StartObject
+        while (reader.Read() && reader.TokenType == JsonTokenType.PropertyName)
+        {
+            if (reader.ValueTextEquals("Items"u8))
+            {
+                reader.Read();
+                result.Items = ReadDynamoRecordItems(ref reader, ref cache);
+            }
+            else if (reader.ValueTextEquals("Count"u8))
+            {
+                reader.Read();
+                reader.GetInt32();
+            }
+            else if (reader.ValueTextEquals("ScannedCount"u8))
+            {
+                reader.Read();
+                result.ScannedCount = reader.GetInt32();
+            }
+            else if (reader.ValueTextEquals("LastEvaluatedKey"u8))
+            {
+                reader.Read();
+                result.LastEvaluatedKey = ReadAttributeMap(ref reader);
+            }
+            else if (reader.ValueTextEquals("ConsumedCapacity"u8))
+            {
+                reader.Read();
+                result.ConsumedCapacity = ReadConsumedCapacity(ref reader);
+            }
+            else
+            {
+                reader.Read();
+                reader.Skip();
+            }
+        }
+
+        return result;
+    }
+
+    internal static GetItemResponse ReadDynamoRecordGetItemResponse(ref Utf8JsonReader reader)
+    {
+        var cache = new PropertyNameCache();
+        var result = new GetItemResponse();
+
+        reader.Read(); // StartObject
+        while (reader.Read() && reader.TokenType == JsonTokenType.PropertyName)
+        {
+            if (reader.ValueTextEquals("Item"u8))
+            {
+                reader.Read();
+                result.Item = ReadDynamoRecordItemCached(ref reader, ref cache);
+            }
+            else if (reader.ValueTextEquals("ConsumedCapacity"u8))
+            {
+                reader.Read();
+                result.ConsumedCapacity = ReadConsumedCapacity(ref reader);
+            }
+            else
+            {
+                reader.Read();
+                reader.Skip();
+            }
+        }
+
+        return result;
+    }
+
+    internal static BatchGetItemResponse ReadDynamoRecordBatchGetItemResponse(ref Utf8JsonReader reader)
+    {
+        var cache = new PropertyNameCache();
+        var result = new BatchGetItemResponse();
+
+        reader.Read(); // StartObject
+        while (reader.Read() && reader.TokenType == JsonTokenType.PropertyName)
+        {
+            if (reader.ValueTextEquals("Responses"u8))
+            {
+                reader.Read();
+                result.Responses = ReadDynamoRecordTableResponses(ref reader, ref cache);
+            }
+            else if (reader.ValueTextEquals("UnprocessedKeys"u8))
+            {
+                reader.Read();
+                result.UnprocessedKeys = ReadUnprocessedKeys(ref reader);
+            }
+            else if (reader.ValueTextEquals("ConsumedCapacity"u8))
+            {
+                reader.Read();
+                result.ConsumedCapacity = ReadConsumedCapacityList(ref reader);
+            }
+            else
+            {
+                reader.Read();
+                reader.Skip();
+            }
+        }
+
+        return result;
+    }
+
+    internal static TransactGetItemResponse ReadDynamoRecordTransactGetItemResponse(ref Utf8JsonReader reader)
+    {
+        var cache = new PropertyNameCache();
+        var result = new TransactGetItemResponse();
+
+        reader.Read(); // StartObject
+        while (reader.Read() && reader.TokenType == JsonTokenType.PropertyName)
+        {
+            if (reader.ValueTextEquals("Responses"u8))
+            {
+                reader.Read();
+                result.Responses = ReadDynamoRecordTransactGetResponses(ref reader, ref cache);
+            }
+            else if (reader.ValueTextEquals("ConsumedCapacity"u8))
+            {
+                reader.Read();
+                result.ConsumedCapacity = ReadConsumedCapacityList(ref reader);
+            }
+            else
+            {
+                reader.Read();
+                reader.Skip();
+            }
+        }
+
+        return result;
+    }
+
+    private static List<DynamoRecord> ReadDynamoRecordItems(ref Utf8JsonReader reader, ref PropertyNameCache cache)
+    {
+        var items = new List<DynamoRecord>();
+        if (reader.TokenType == JsonTokenType.Null)
+            return items;
+        while (reader.Read() && reader.TokenType != JsonTokenType.EndArray)
+            items.Add(ReadDynamoRecordItemCached(ref reader, ref cache));
+        return items;
+    }
+
+    private static Dictionary<string, List<DynamoRecord>> ReadDynamoRecordTableResponses(ref Utf8JsonReader reader, ref PropertyNameCache cache)
+    {
+        var responses = new Dictionary<string, List<DynamoRecord>>();
+        while (reader.Read() && reader.TokenType != JsonTokenType.EndObject)
+        {
+            var tableName = reader.GetString()!;
+            reader.Read(); // StartArray
+            responses[tableName] = ReadDynamoRecordItems(ref reader, ref cache);
+        }
+        return responses;
+    }
+
+    private static List<TransactGetResult> ReadDynamoRecordTransactGetResponses(ref Utf8JsonReader reader, ref PropertyNameCache cache)
+    {
+        var items = new List<TransactGetResult>();
+        while (reader.Read() && reader.TokenType != JsonTokenType.EndArray)
+        {
+            DynamoRecord? item = null;
+            while (reader.Read() && reader.TokenType != JsonTokenType.EndObject)
+            {
+                if (reader.ValueTextEquals("Item"u8))
+                {
+                    reader.Read();
+                    item = ReadDynamoRecordItemCached(ref reader, ref cache);
+                }
+                else
+                {
+                    reader.Read();
+                    reader.Skip();
+                }
+            }
+            items.Add(new TransactGetResult { Item = item });
+        }
+        return items;
+    }
+
     private static List<T> ReadItems<T>(ref Utf8JsonReader reader, DynamoItemReader<T> itemReader)
     {
         var items = new List<T>();
diff --git a/src/Clients/Goa.Clients.Dynamo/Internal/DynamoResponseReaderRegistry.cs b/src/Clients/Goa.Clients.Dynamo/Internal/DynamoResponseReaderRegistry.cs
index a6097702..b03d2f22 100644
--- a/src/Clients/Goa.Clients.Dynamo/Internal/DynamoResponseReaderRegistry.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Internal/DynamoResponseReaderRegistry.cs
@@ -30,6 +30,7 @@ private static class Cache<T>
 
         static Cache()
         {
+#pragma warning disable GOA1503 // One-time method group allocations cached in static readonly fields
             if (typeof(T) == typeof(QueryResponse))
                 Reader = (JsonReader<T>)(object)(JsonReader<QueryResponse>)ReadQueryResponse;
             else if (typeof(T) == typeof(ScanResponse))
@@ -42,6 +43,7 @@ static Cache()
                 Reader = (JsonReader<T>)(object)(JsonReader<TransactGetItemResponse>)ReadTransactGetItemResponse;
             else
                 Reader = FallbackReader;
+#pragma warning restore GOA1503
         }
 
         private static T FallbackReader(ref Utf8JsonReader reader)
@@ -55,55 +57,26 @@ as System.Text.Json.Serialization.Metadata.JsonTypeInfo<T>
 
     private static QueryResponse ReadQueryResponse(ref Utf8JsonReader reader)
     {
-        var result = DynamoResponseReader.ReadQueryResponse(ref reader, DynamoResponseReader.ReadDynamoRecordItem);
-        return new QueryResponse
-        {
-            Items = result.Items,
-            LastEvaluatedKey = result.LastEvaluatedKey,
-            ScannedCount = result.ScannedCount,
-            ConsumedCapacity = result.ConsumedCapacity
-        };
+        return DynamoResponseReader.ReadDynamoRecordQueryResponse(ref reader);
     }
 
     private static ScanResponse ReadScanResponse(ref Utf8JsonReader reader)
     {
-        var result = DynamoResponseReader.ReadScanResponse(ref reader, DynamoResponseReader.ReadDynamoRecordItem);
-        return new ScanResponse
-        {
-            Items = result.Items,
-            LastEvaluatedKey = result.LastEvaluatedKey,
-            ScannedCount = result.ScannedCount,
-            ConsumedCapacity = result.ConsumedCapacity
-        };
+        return DynamoResponseReader.ReadDynamoRecordScanResponse(ref reader);
     }
 
     private static GetItemResponse ReadGetItemResponse(ref Utf8JsonReader reader)
     {
-        var item = DynamoResponseReader.ReadGetItemResponse(ref reader, DynamoResponseReader.ReadDynamoRecordItem);
-        return new GetItemResponse { Item = item };
+        return DynamoResponseReader.ReadDynamoRecordGetItemResponse(ref reader);
     }
 
     private static BatchGetItemResponse ReadBatchGetItemResponse(ref Utf8JsonReader reader)
     {
-        var result = DynamoResponseReader.ReadBatchGetItemResponse(ref reader, DynamoResponseReader.ReadDynamoRecordItem);
-        return new BatchGetItemResponse
-        {
-            Responses = result.Responses,
-            UnprocessedKeys = result.UnprocessedKeys,
-            ConsumedCapacity = result.ConsumedCapacity
-        };
+        return DynamoResponseReader.ReadDynamoRecordBatchGetItemResponse(ref reader);
     }
 
     private static TransactGetItemResponse ReadTransactGetItemResponse(ref Utf8JsonReader reader)
     {
-        var result = DynamoResponseReader.ReadTransactGetItemResponse(ref reader, DynamoResponseReader.ReadDynamoRecordItem);
-        var responses = new List<TransactGetResult>(result.Items.Count);
-        foreach (var item in result.Items)
-            responses.Add(new TransactGetResult { Item = item });
-        return new TransactGetItemResponse
-        {
-            Responses = responses,
-            ConsumedCapacity = result.ConsumedCapacity
-        };
+        return DynamoResponseReader.ReadDynamoRecordTransactGetItemResponse(ref reader);
     }
 }
diff --git a/src/Clients/Goa.Clients.Dynamo/Internal/PropertyNameCache.cs b/src/Clients/Goa.Clients.Dynamo/Internal/PropertyNameCache.cs
index 2b24d719..8cc45c8f 100644
--- a/src/Clients/Goa.Clients.Dynamo/Internal/PropertyNameCache.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Internal/PropertyNameCache.cs
@@ -11,7 +11,11 @@ internal struct PropertyNameCache
 {
     private readonly Dictionary<ulong, string> _cache;
 
-    public PropertyNameCache(int capacity = 16)
+    public PropertyNameCache() : this(15)
+    {
+    }
+
+    public PropertyNameCache(int capacity)
     {
         _cache = new Dictionary<ulong, string>(capacity);
     }
diff --git a/src/Clients/Goa.Clients.Dynamo/Models/CapacityDetail.cs b/src/Clients/Goa.Clients.Dynamo/Models/CapacityDetail.cs
index ec82cc43..017f9d42 100644
--- a/src/Clients/Goa.Clients.Dynamo/Models/CapacityDetail.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Models/CapacityDetail.cs
@@ -5,7 +5,7 @@ namespace Goa.Clients.Dynamo.Models;
 /// <summary>
 /// Detailed capacity information for DynamoDB operations.
 /// </summary>
-public class CapacityDetail
+public sealed class CapacityDetail
 {
     /// <summary>
     /// The number of read capacity units consumed by the operation.
diff --git a/src/Clients/Goa.Clients.Dynamo/Models/ConsumedCapacity.cs b/src/Clients/Goa.Clients.Dynamo/Models/ConsumedCapacity.cs
index 5deb7288..6a3ef92c 100644
--- a/src/Clients/Goa.Clients.Dynamo/Models/ConsumedCapacity.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Models/ConsumedCapacity.cs
@@ -5,7 +5,7 @@ namespace Goa.Clients.Dynamo.Models;
 /// <summary>
 /// Represents consumed capacity information for DynamoDB operations.
 /// </summary>
-public class ConsumedCapacity
+public sealed class ConsumedCapacity
 {
     /// <summary>
     /// The name of the table that was affected by the operation.
diff --git a/src/Clients/Goa.Clients.Dynamo/Models/DynamoRecord.cs b/src/Clients/Goa.Clients.Dynamo/Models/DynamoRecord.cs
index 71a9ea12..ea22c5e8 100644
--- a/src/Clients/Goa.Clients.Dynamo/Models/DynamoRecord.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Models/DynamoRecord.cs
@@ -3,7 +3,7 @@ namespace Goa.Clients.Dynamo.Models;
 /// <summary>
 /// Represents a DynamoDB record with strongly-typed attribute values.
 /// </summary>
-public class DynamoRecord : Dictionary<string, AttributeValue>
+public sealed class DynamoRecord : Dictionary<string, AttributeValue>
 {
     /// <summary>
     /// Initializes a new, empty instance of the <see cref="DynamoRecord"/> class.
diff --git a/src/Clients/Goa.Clients.Dynamo/Models/ItemCollectionMetrics.cs b/src/Clients/Goa.Clients.Dynamo/Models/ItemCollectionMetrics.cs
index bd3eb9c4..19d3f1a4 100644
--- a/src/Clients/Goa.Clients.Dynamo/Models/ItemCollectionMetrics.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Models/ItemCollectionMetrics.cs
@@ -5,7 +5,7 @@ namespace Goa.Clients.Dynamo.Models;
 /// <summary>
 /// Information about item collections, if any, that were affected by the operation.
 /// </summary>
-public class ItemCollectionMetrics
+public sealed class ItemCollectionMetrics
 {
     /// <summary>
     /// The partition key value of the item collection.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchGetItemBuilder.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchGetItemBuilder.cs
index 71356ed0..c8a12346 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchGetItemBuilder.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchGetItemBuilder.cs
@@ -5,7 +5,7 @@ namespace Goa.Clients.Dynamo.Operations.Batch;
 /// <summary>
 /// Fluent builder for constructing DynamoDB BatchGetItem requests with a user-friendly API.
 /// </summary>
-public class BatchGetItemBuilder
+public sealed class BatchGetItemBuilder
 {
     private readonly BatchGetItemRequest _request = new()
     {
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchGetItemRequest.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchGetItemRequest.cs
index 20e38bf6..e33c469a 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchGetItemRequest.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchGetItemRequest.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations.Batch;
 /// <summary>
 /// Request for batch getting items from DynamoDB.
 /// </summary>
-public class BatchGetItemRequest
+public sealed class BatchGetItemRequest
 {
     /// <summary>
     /// A map of one or more table names and, for each table, a map that describes one or more items to retrieve from that table.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchGetItemResponse.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchGetItemResponse.cs
index 61232af3..f6ae1aac 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchGetItemResponse.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchGetItemResponse.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations.Batch;
 /// <summary>
 /// Response for BatchGetItem operations.
 /// </summary>
-public class BatchGetItemResponse
+public sealed class BatchGetItemResponse
 {
     /// <summary>
     /// A map of table name to a list of items. Each item is represented as a set of attributes.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchGetRequestItem.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchGetRequestItem.cs
index 6c1c8876..7b783e66 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchGetRequestItem.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchGetRequestItem.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations.Batch;
 /// <summary>
 /// Individual table request within a BatchGetItem operation.
 /// </summary>
-public class BatchGetRequestItem
+public sealed class BatchGetRequestItem
 {
     /// <summary>
     /// The primary keys of the items to retrieve. For each key, DynamoDB performs a GetItem operation and returns the entire item.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchGetTableBuilder.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchGetTableBuilder.cs
index 64f66bcc..4d544fe1 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchGetTableBuilder.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchGetTableBuilder.cs
@@ -5,7 +5,7 @@ namespace Goa.Clients.Dynamo.Operations.Batch;
 /// <summary>
 /// Fluent builder for configuring table-specific requests within a BatchGetItem operation.
 /// </summary>
-public class BatchGetTableBuilder
+public sealed class BatchGetTableBuilder
 {
     private readonly BatchGetRequestItem _request = new()
     {
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchWriteItemBuilder.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchWriteItemBuilder.cs
index c3f5c117..1689fc90 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchWriteItemBuilder.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchWriteItemBuilder.cs
@@ -5,7 +5,7 @@ namespace Goa.Clients.Dynamo.Operations.Batch;
 /// <summary>
 /// Fluent builder for constructing DynamoDB BatchWriteItem requests with a user-friendly API.
 /// </summary>
-public class BatchWriteItemBuilder
+public sealed class BatchWriteItemBuilder
 {
     private readonly BatchWriteItemRequest _request = new()
     {
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchWriteItemRequest.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchWriteItemRequest.cs
index 97b26738..2063ac63 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchWriteItemRequest.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchWriteItemRequest.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations.Batch;
 /// <summary>
 /// Request for batch writing items to DynamoDB.
 /// </summary>
-public class BatchWriteItemRequest
+public sealed class BatchWriteItemRequest
 {
     /// <summary>
     /// A map of one or more table names and, for each table, a list of operations to be performed.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchWriteItemResponse.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchWriteItemResponse.cs
index af643513..aa1169c7 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchWriteItemResponse.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchWriteItemResponse.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations.Batch;
 /// <summary>
 /// Response for BatchWriteItem operations.
 /// </summary>
-public class BatchWriteItemResponse
+public sealed class BatchWriteItemResponse
 {
     /// <summary>
     /// A map of tables and requests against those tables that were not processed.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchWriteRequestItem.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchWriteRequestItem.cs
index 12522fa6..a0896a80 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchWriteRequestItem.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchWriteRequestItem.cs
@@ -5,7 +5,7 @@ namespace Goa.Clients.Dynamo.Operations.Batch;
 /// <summary>
 /// Individual write request within a BatchWriteItem operation.
 /// </summary>
-public class BatchWriteRequestItem
+public sealed class BatchWriteRequestItem
 {
     /// <summary>
     /// A request to perform a PutItem operation.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchWriteResult.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchWriteResult.cs
index 8a69683b..fdd8044b 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchWriteResult.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchWriteResult.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations.Batch;
 /// <summary>
 /// Result wrapper for BatchWrite operations.
 /// </summary>
-public class BatchWriteResult
+public sealed class BatchWriteResult
 {
     /// <summary>
     /// Put items that were not processed during the BatchWriteItem operation.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchWriteTableBuilder.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchWriteTableBuilder.cs
index c91c91a6..70973913 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchWriteTableBuilder.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/BatchWriteTableBuilder.cs
@@ -5,7 +5,7 @@ namespace Goa.Clients.Dynamo.Operations.Batch;
 /// <summary>
 /// Fluent builder for configuring table-specific requests within a BatchWriteItem operation.
 /// </summary>
-public class BatchWriteTableBuilder
+public sealed class BatchWriteTableBuilder
 {
     private readonly List<BatchWriteRequestItem> _requests = new();
 
@@ -30,7 +30,9 @@ public BatchWriteTableBuilder WithDelete(Dictionary<string, AttributeValue> key)
     /// <returns>The BatchWriteTableBuilder instance for method chaining.</returns>
     public BatchWriteTableBuilder WithDelete(IEnumerable<Dictionary<string, AttributeValue>> keys)
     {
+#pragma warning disable GOA1301 // Enumerator allocation unavoidable - IEnumerable is public API parameter type
         foreach (var key in keys)
+#pragma warning restore GOA1301
         {
             WithDelete(key);
         }
@@ -58,7 +60,9 @@ public BatchWriteTableBuilder WithPut(Dictionary<string, AttributeValue> item)
     /// <returns>The BatchWriteTableBuilder instance for method chaining.</returns>
     public BatchWriteTableBuilder WithPut(IEnumerable<Dictionary<string, AttributeValue>> items)
     {
+#pragma warning disable GOA1301 // Enumerator allocation unavoidable - IEnumerable is public API parameter type
         foreach (var item in items)
+#pragma warning restore GOA1301
         {
             WithPut(item);
         }
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/DeleteRequest.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/DeleteRequest.cs
index dcaf8f65..7625bfb3 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/DeleteRequest.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/DeleteRequest.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations.Batch;
 /// <summary>
 /// Delete request within a batch write operation.
 /// </summary>
-public class DeleteRequest
+public sealed class DeleteRequest
 {
     /// <summary>
     /// The primary key of the item to be deleted.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/PutRequest.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/PutRequest.cs
index c0d766c8..b37c9021 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Batch/PutRequest.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Batch/PutRequest.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations.Batch;
 /// <summary>
 /// Put request within a batch write operation.
 /// </summary>
-public class PutRequest
+public sealed class PutRequest
 {
     /// <summary>
     /// A map of attribute names to AttributeValue objects representing the item to be put.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Condition.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Condition.cs
index 8b304601..a5584bdd 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Condition.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Condition.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations;
 /// <summary>
 /// Represents a condition expression for DynamoDB operations with associated attribute names and values.
 /// </summary>
-public class Condition
+public sealed class Condition
 {
     /// <summary>
     /// Gets the condition expression string.
@@ -41,8 +41,14 @@ public Condition(string expression)
     public Condition(string expression, IEnumerable<KeyValuePair<string, string>> expressionNames, IEnumerable<KeyValuePair<string, AttributeValue>> expressionValues)
     {
         Expression = expression;
-        ExpressionNames = expressionNames.ToDictionary();
-        ExpressionValues = expressionValues.ToDictionary();
+        var names = new Dictionary<string, string>();
+        foreach (var kvp in expressionNames)
+            names.Add(kvp.Key, kvp.Value);
+        ExpressionNames = names;
+        var values = new Dictionary<string, AttributeValue>();
+        foreach (var kvp in expressionValues)
+            values.Add(kvp.Key, kvp.Value);
+        ExpressionValues = values;
     }
 
     /// <summary>
@@ -294,10 +300,19 @@ public static Condition And(Condition left, Condition right)
     /// <returns>A condition representing the logical AND of all conditions.</returns>
     public static Condition And(params Condition[] conditions)
     {
-        var expression = string.Join(" AND ", conditions.Select(c => c.Expression));
-        var expressionNames = conditions.SelectMany(c => c.ExpressionNames).ToDictionary();
-        var expressionValues = conditions.SelectMany(c => c.ExpressionValues).ToDictionary();
-        return new Condition(expression, expressionNames, expressionValues);
+        var sb = new System.Text.StringBuilder();
+        var expressionNames = new Dictionary<string, string>();
+        var expressionValues = new Dictionary<string, AttributeValue>();
+        for (var i = 0; i < conditions.Length; i++)
+        {
+            if (i > 0) sb.Append(" AND ");
+            sb.Append(conditions[i].Expression);
+            foreach (var kvp in conditions[i].ExpressionNames)
+                expressionNames.Add(kvp.Key, kvp.Value);
+            foreach (var kvp in conditions[i].ExpressionValues)
+                expressionValues.Add(kvp.Key, kvp.Value);
+        }
+        return new Condition(sb.ToString(), expressionNames, expressionValues);
     }
 
     /// <summary>
@@ -321,10 +336,19 @@ public static Condition Or(Condition left, Condition right)
     /// <returns>A condition representing the logical OR of all conditions.</returns>
     public static Condition Or(params Condition[] conditions)
     {
-        var expression = string.Join(" OR ", conditions.Select(c => c.Expression));
-        var expressionNames = conditions.SelectMany(c => c.ExpressionNames).ToDictionary();
-        var expressionValues = conditions.SelectMany(c => c.ExpressionValues).ToDictionary();
-        return new Condition(expression, expressionNames, expressionValues);
+        var sb = new System.Text.StringBuilder();
+        var expressionNames = new Dictionary<string, string>();
+        var expressionValues = new Dictionary<string, AttributeValue>();
+        for (var i = 0; i < conditions.Length; i++)
+        {
+            if (i > 0) sb.Append(" OR ");
+            sb.Append(conditions[i].Expression);
+            foreach (var kvp in conditions[i].ExpressionNames)
+                expressionNames.Add(kvp.Key, kvp.Value);
+            foreach (var kvp in conditions[i].ExpressionValues)
+                expressionValues.Add(kvp.Key, kvp.Value);
+        }
+        return new Condition(sb.ToString(), expressionNames, expressionValues);
     }
 
     /// <summary>
@@ -338,10 +362,17 @@ public static Condition In(string attributeName, params AttributeValue[] values)
         if (values is null || values.Length == 0)
             throw new ArgumentException("At least one value must be provided for IN condition", nameof(values));
 
-        var valueParams = values.Select((_, i) => $":{attributeName}{i}").ToArray();
+#pragma warning disable GOA1401 // Explicit arrays required for building expression parameters
+        var valueParams = new string[values.Length];
+        var expressionValues = new KeyValuePair<string, AttributeValue>[values.Length];
+        for (var i = 0; i < values.Length; i++)
+        {
+            valueParams[i] = $":{attributeName}{i}";
+            expressionValues[i] = new KeyValuePair<string, AttributeValue>($":{attributeName}{i}", values[i]);
+        }
         var expression = $"#{attributeName} IN ({string.Join(", ", valueParams)})";
-        var expressionNames = new[] { new KeyValuePair<string, string>($"#{attributeName}", attributeName) };
-        var expressionValues = values.Select((value, i) => new KeyValuePair<string, AttributeValue>($":{attributeName}{i}",  value));
+        var expressionNames = new KeyValuePair<string, string>[] { new($"#{attributeName}", attributeName) };
+#pragma warning restore GOA1401
         return new Condition(expression, expressionNames, expressionValues);
     }
 }
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/DeleteItem/DeleteItemBuilder.cs b/src/Clients/Goa.Clients.Dynamo/Operations/DeleteItem/DeleteItemBuilder.cs
index 184d8f45..35eba6d3 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/DeleteItem/DeleteItemBuilder.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/DeleteItem/DeleteItemBuilder.cs
@@ -8,7 +8,7 @@ namespace Goa.Clients.Dynamo.Operations.DeleteItem;
 /// Fluent builder for constructing DynamoDB DeleteItem requests with a user-friendly API.
 /// </summary>
 /// <param name="tableName">The name of the table to delete the item from.</param>
-public class DeleteItemBuilder(string tableName)
+public sealed class DeleteItemBuilder(string tableName)
 {
     private readonly DeleteItemRequest _request = new()
     {
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/DeleteItem/DeleteItemRequest.cs b/src/Clients/Goa.Clients.Dynamo/Operations/DeleteItem/DeleteItemRequest.cs
index d3b30b93..b7b14f84 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/DeleteItem/DeleteItemRequest.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/DeleteItem/DeleteItemRequest.cs
@@ -7,7 +7,7 @@ namespace Goa.Clients.Dynamo.Operations.DeleteItem;
 /// <summary>
 /// Request for deleting an item from DynamoDB.
 /// </summary>
-public class DeleteItemRequest
+public sealed class DeleteItemRequest
 {
     /// <summary>
     /// The name of the table from which to delete the item.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/DeleteItem/DeleteItemResponse.cs b/src/Clients/Goa.Clients.Dynamo/Operations/DeleteItem/DeleteItemResponse.cs
index 44575d12..f7e3abe7 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/DeleteItem/DeleteItemResponse.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/DeleteItem/DeleteItemResponse.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations.DeleteItem;
 /// <summary>
 /// Response for DeleteItem operations.
 /// </summary>
-public class DeleteItemResponse
+public sealed class DeleteItemResponse
 {
     /// <summary>
     /// A map of attribute names to AttributeValue objects representing the item as it appeared before it was deleted.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/GetItem/GetItemBuilder.cs b/src/Clients/Goa.Clients.Dynamo/Operations/GetItem/GetItemBuilder.cs
index f6a50a47..70f7e959 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/GetItem/GetItemBuilder.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/GetItem/GetItemBuilder.cs
@@ -7,7 +7,7 @@ namespace Goa.Clients.Dynamo.Operations.GetItem;
 /// Fluent builder for constructing DynamoDB GetItem requests with a user-friendly API.
 /// </summary>
 /// <param name="tableName">The name of the table to get the item from.</param>
-public class GetItemBuilder(string tableName)
+public sealed class GetItemBuilder(string tableName)
 {
     private readonly GetItemRequest _request = new()
     {
@@ -64,7 +64,7 @@ public GetItemBuilder WithProjection(params string[] attributes)
     /// <returns>The GetItemBuilder instance for method chaining.</returns>
     public GetItemBuilder WithProjection(IEnumerable<string> attributes)
     {
-        if (attributes?.Any() == true)
+        if (attributes is ICollection<string> { Count: > 0 })
         {
             _request.ProjectionExpression = string.Join(", ", attributes);
         }
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/GetItem/GetItemRequest.cs b/src/Clients/Goa.Clients.Dynamo/Operations/GetItem/GetItemRequest.cs
index d76357cd..acba3f41 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/GetItem/GetItemRequest.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/GetItem/GetItemRequest.cs
@@ -7,7 +7,7 @@ namespace Goa.Clients.Dynamo.Operations.GetItem;
 /// <summary>
 /// Request for getting an item from DynamoDB.
 /// </summary>
-public class GetItemRequest
+public sealed class GetItemRequest
 {
     /// <summary>
     /// The name of the table containing the requested item.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/GetItem/GetItemResponse.cs b/src/Clients/Goa.Clients.Dynamo/Operations/GetItem/GetItemResponse.cs
index 23ebfa8c..ffa40028 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/GetItem/GetItemResponse.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/GetItem/GetItemResponse.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations.GetItem;
 /// <summary>
 /// Response for GetItem operations.
 /// </summary>
-public class GetItemResponse
+public sealed class GetItemResponse
 {
     /// <summary>
     /// A map of attribute names to AttributeValue objects, as specified by ProjectionExpression.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/PutItem/PutItemBuilder.cs b/src/Clients/Goa.Clients.Dynamo/Operations/PutItem/PutItemBuilder.cs
index 4e2901d5..582de370 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/PutItem/PutItemBuilder.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/PutItem/PutItemBuilder.cs
@@ -8,7 +8,7 @@ namespace Goa.Clients.Dynamo.Operations.PutItem;
 /// Fluent builder for constructing DynamoDB PutItem requests with a user-friendly API.
 /// </summary>
 /// <param name="tableName">The name of the table to put the item into.</param>
-public class PutItemBuilder(string tableName)
+public sealed class PutItemBuilder(string tableName)
 {
     private readonly PutItemRequest _request = new()
     {
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/PutItem/PutItemRequest.cs b/src/Clients/Goa.Clients.Dynamo/Operations/PutItem/PutItemRequest.cs
index 0412ff60..88bd3356 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/PutItem/PutItemRequest.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/PutItem/PutItemRequest.cs
@@ -7,7 +7,7 @@ namespace Goa.Clients.Dynamo.Operations.PutItem;
 /// <summary>
 /// Request for putting an item into DynamoDB.
 /// </summary>
-public class PutItemRequest
+public sealed class PutItemRequest
 {
     /// <summary>
     /// The name of the table to contain the item.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/PutItem/PutItemResponse.cs b/src/Clients/Goa.Clients.Dynamo/Operations/PutItem/PutItemResponse.cs
index 264f2e06..38cf2b82 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/PutItem/PutItemResponse.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/PutItem/PutItemResponse.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations.PutItem;
 /// <summary>
 /// Response for PutItem operations.
 /// </summary>
-public class PutItemResponse
+public sealed class PutItemResponse
 {
     /// <summary>
     /// The attribute values as they appeared before the PutItem operation,
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Query/QueryBuilder.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Query/QueryBuilder.cs
index 0a1e77b3..8f671826 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Query/QueryBuilder.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Query/QueryBuilder.cs
@@ -149,7 +149,7 @@ public QueryBuilder WithProjection(params string[] attributes)
     /// <returns>The QueryBuilder instance for method chaining.</returns>
     public QueryBuilder WithProjection(IEnumerable<string> attributes)
     {
-        if (attributes?.Any() == true)
+        if (attributes is ICollection<string> { Count: > 0 })
         {
             _request.ProjectionExpression = string.Join(", ", attributes);
             return WithSelectionMode(Select.SPECIFIC_ATTRIBUTES);
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Query/QueryRequest.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Query/QueryRequest.cs
index 01d15151..d9f5f4fc 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Query/QueryRequest.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Query/QueryRequest.cs
@@ -7,7 +7,7 @@ namespace Goa.Clients.Dynamo.Operations.Query;
 /// <summary>
 /// Request for querying items from DynamoDB.
 /// </summary>
-public class QueryRequest
+public sealed class QueryRequest
 {
     /// <summary>
     /// The name of the table containing the requested items.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Query/QueryResponse.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Query/QueryResponse.cs
index d6606f10..d6420f1b 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Query/QueryResponse.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Query/QueryResponse.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations.Query;
 /// <summary>
 /// Response for Query operations with pagination support.
 /// </summary>
-public class QueryResponse
+public sealed class QueryResponse
 {
     /// <summary>
     /// An array of item attributes that match the query criteria.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Query/QueryResult.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Query/QueryResult.cs
index c3695f8b..6c73e0e4 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Query/QueryResult.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Query/QueryResult.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations.Query;
 /// <summary>
 /// Result wrapper for Query operations with pagination support.
 /// </summary>
-public class QueryResult
+public sealed class QueryResult
 {
     /// <summary>
     /// The items returned by the Query operation.
@@ -51,7 +51,7 @@ public class QueryResult
 /// Typed result wrapper for Query operations with direct deserialization support.
 /// </summary>
 /// <typeparam name="T">The type of the deserialized items.</typeparam>
-public class QueryResult<T>
+public sealed class QueryResult<T>
 {
     /// <inheritdoc cref="QueryResult.Items"/>
     [JsonPropertyName("Items")]
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Scan/ScanBuilder.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Scan/ScanBuilder.cs
index 9231ffde..67505944 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Scan/ScanBuilder.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Scan/ScanBuilder.cs
@@ -8,7 +8,7 @@ namespace Goa.Clients.Dynamo.Operations.Scan;
 /// Fluent builder for constructing DynamoDB Scan requests with a user-friendly API.
 /// </summary>
 /// <param name="tableName">The name of the table to scan.</param>
-public class ScanBuilder(string tableName)
+public sealed class ScanBuilder(string tableName)
 {
     private readonly ScanRequest _request = new()
     {
@@ -103,7 +103,7 @@ public ScanBuilder WithProjection(params string[] attributes)
     /// <returns>The ScanBuilder instance for method chaining.</returns>
     public ScanBuilder WithProjection(IEnumerable<string> attributes)
     {
-        if (attributes?.Any() == true)
+        if (attributes is ICollection<string> { Count: > 0 })
         {
             _request.ProjectionExpression = string.Join(", ", attributes);
             return WithSelectionMode(Select.SPECIFIC_ATTRIBUTES);
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Scan/ScanRequest.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Scan/ScanRequest.cs
index 8213917d..279e994e 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Scan/ScanRequest.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Scan/ScanRequest.cs
@@ -7,7 +7,7 @@ namespace Goa.Clients.Dynamo.Operations.Scan;
 /// <summary>
 /// Request for scanning items from DynamoDB.
 /// </summary>
-public class ScanRequest
+public sealed class ScanRequest
 {
     /// <summary>
     /// The name of the table containing the requested items.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Scan/ScanResponse.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Scan/ScanResponse.cs
index b9fb807e..7f7faba4 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Scan/ScanResponse.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Scan/ScanResponse.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations.Scan;
 /// <summary>
 /// Response for Scan operations with pagination support.
 /// </summary>
-public class ScanResponse
+public sealed class ScanResponse
 {
     /// <summary>
     /// An array of item attributes that match the scan criteria.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Scan/ScanResult.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Scan/ScanResult.cs
index a47eb3ea..fbdfc418 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Scan/ScanResult.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Scan/ScanResult.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations.Scan;
 /// <summary>
 /// Result wrapper for Scan operations with pagination support.
 /// </summary>
-public class ScanResult
+public sealed class ScanResult
 {
     /// <summary>
     /// The items returned by the Scan operation.
@@ -51,7 +51,7 @@ public class ScanResult
 /// Typed result wrapper for Scan operations with direct deserialization support.
 /// </summary>
 /// <typeparam name="T">The type of the deserialized items.</typeparam>
-public class ScanResult<T>
+public sealed class ScanResult<T>
 {
     /// <inheritdoc cref="ScanResult.Items"/>
     [JsonPropertyName("Items")]
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactConditionCheckItem.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactConditionCheckItem.cs
index a7e46638..31ac4371 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactConditionCheckItem.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactConditionCheckItem.cs
@@ -7,7 +7,7 @@ namespace Goa.Clients.Dynamo.Operations.Transactions;
 /// <summary>
 /// Condition check operation in a transaction.
 /// </summary>
-public class TransactConditionCheckItem
+public sealed class TransactConditionCheckItem
 {
     /// <summary>
     /// The name of the table containing the requested item.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactDeleteItem.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactDeleteItem.cs
index b19bc059..729c122d 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactDeleteItem.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactDeleteItem.cs
@@ -7,7 +7,7 @@ namespace Goa.Clients.Dynamo.Operations.Transactions;
 /// <summary>
 /// Delete operation in a transaction.
 /// </summary>
-public class TransactDeleteItem
+public sealed class TransactDeleteItem
 {
     /// <summary>
     /// The name of the table from which to delete the item.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactGetBuilder.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactGetBuilder.cs
index c8ab5981..8f30c926 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactGetBuilder.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactGetBuilder.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations.Transactions;
 /// <summary>
 /// Fluent builder for constructing DynamoDB TransactGet requests with a user-friendly API.
 /// </summary>
-public class TransactGetBuilder
+public sealed class TransactGetBuilder
 {
     private readonly TransactGetRequest _request = new();
 
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactGetItem.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactGetItem.cs
index e41a7057..5cad71d3 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactGetItem.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactGetItem.cs
@@ -5,7 +5,7 @@ namespace Goa.Clients.Dynamo.Operations.Transactions;
 /// <summary>
 /// Individual transact get item.
 /// </summary>
-public class TransactGetItem
+public sealed class TransactGetItem
 {
     /// <summary>
     /// Contains the primary key that identifies the item to get, together with the name of the table that contains the item.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactGetItemRequest.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactGetItemRequest.cs
index 3a37f75c..2bc0dec9 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactGetItemRequest.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactGetItemRequest.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations.Transactions;
 /// <summary>
 /// Get request within a transact get operation.
 /// </summary>
-public class TransactGetItemRequest
+public sealed class TransactGetItemRequest
 {
     /// <summary>
     /// The name of the table containing the requested item.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactGetItemResponse.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactGetItemResponse.cs
index 9ca8c401..1fa71f78 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactGetItemResponse.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactGetItemResponse.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations.Transactions;
 /// <summary>
 /// Response for TransactGetItem operations.
 /// </summary>
-public class TransactGetItemResponse
+public sealed class TransactGetItemResponse
 {
     /// <summary>
     /// An ordered array of up to 100 response items, each of which corresponds to the TransactGetItem request in the same position.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactGetRequest.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactGetRequest.cs
index 692cf43e..d83c308c 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactGetRequest.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactGetRequest.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations.Transactions;
 /// <summary>
 /// Request for transactional get operations.
 /// </summary>
-public class TransactGetRequest
+public sealed class TransactGetRequest
 {
     /// <summary>
     /// An ordered array of up to 100 TransactGetItem objects, each of which contains a Get operation.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactGetResult.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactGetResult.cs
index c7960c32..96d911d0 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactGetResult.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactGetResult.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations.Transactions;
 /// <summary>
 /// Result item from TransactGetItem operation.
 /// </summary>
-public class TransactGetResult
+public sealed class TransactGetResult
 {
     /// <summary>
     /// Map of attribute names to values for the requested item, or null if the item was not found.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactPutItem.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactPutItem.cs
index 5fd27526..4f7aa1d1 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactPutItem.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactPutItem.cs
@@ -7,7 +7,7 @@ namespace Goa.Clients.Dynamo.Operations.Transactions;
 /// <summary>
 /// Put operation in a transaction.
 /// </summary>
-public class TransactPutItem
+public sealed class TransactPutItem
 {
     /// <summary>
     /// The name of the table to contain the item.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactUpdateItem.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactUpdateItem.cs
index aa9f671f..0f3a645c 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactUpdateItem.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactUpdateItem.cs
@@ -7,7 +7,7 @@ namespace Goa.Clients.Dynamo.Operations.Transactions;
 /// <summary>
 /// Update operation in a transaction.
 /// </summary>
-public class TransactUpdateItem
+public sealed class TransactUpdateItem
 {
     /// <summary>
     /// The name of the table containing the item to be updated.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactWriteBuilder.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactWriteBuilder.cs
index 071fc177..34d92147 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactWriteBuilder.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactWriteBuilder.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations.Transactions;
 /// <summary>
 /// Fluent builder for constructing DynamoDB TransactWrite requests with a user-friendly API.
 /// </summary>
-public class TransactWriteBuilder
+public sealed class TransactWriteBuilder
 {
     private readonly TransactWriteRequest _request = new()
     {
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactWriteItem.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactWriteItem.cs
index 20ec5540..7abae7cf 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactWriteItem.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactWriteItem.cs
@@ -5,7 +5,7 @@ namespace Goa.Clients.Dynamo.Operations.Transactions;
 /// <summary>
 /// Individual transact write item.
 /// </summary>
-public class TransactWriteItem
+public sealed class TransactWriteItem
 {
     /// <summary>
     /// A request to perform a PutItem operation.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactWriteItemResponse.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactWriteItemResponse.cs
index 08bf2f0b..d0ba3ce9 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactWriteItemResponse.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactWriteItemResponse.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations.Transactions;
 /// <summary>
 /// Response for TransactWriteItem operations.
 /// </summary>
-public class TransactWriteItemResponse
+public sealed class TransactWriteItemResponse
 {
     /// <summary>
     /// The capacity units consumed by the entire TransactWriteItem operation.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactWriteOperation.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactWriteOperation.cs
index 85f84da6..928e6c63 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactWriteOperation.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactWriteOperation.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations.Transactions;
 /// <summary>
 /// Represents a transaction write operation.
 /// </summary>
-public class TransactWriteOperation
+public sealed class TransactWriteOperation
 {
     /// <summary>
     /// The type of operation to perform (Put, Update, Delete, or ConditionCheck).
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactWriteRequest.cs b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactWriteRequest.cs
index 6a1cec6e..be91d7cd 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactWriteRequest.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/Transactions/TransactWriteRequest.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations.Transactions;
 /// <summary>
 /// Request for transactional write operations.
 /// </summary>
-public class TransactWriteRequest
+public sealed class TransactWriteRequest
 {
     /// <summary>
     /// An ordered array of up to 100 TransactWriteItem objects, each of which contains a ConditionCheck, Put, Update, or Delete operation.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/UpdateItem/UpdateItemBuilder.cs b/src/Clients/Goa.Clients.Dynamo/Operations/UpdateItem/UpdateItemBuilder.cs
index 76ae1e43..77e05ed4 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/UpdateItem/UpdateItemBuilder.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/UpdateItem/UpdateItemBuilder.cs
@@ -663,7 +663,7 @@ public UpdateItemBuilder AddToStringSet(string attributeName, params string[] va
             var valueKey = $":v{_request.ExpressionAttributeValues.Count}";
 
             _request.ExpressionAttributeNames[nameKey] = attributeName;
-            _request.ExpressionAttributeValues[valueKey] = AttributeValue.FromStringSet(values.ToList());
+            _request.ExpressionAttributeValues[valueKey] = AttributeValue.FromStringSet(new List<string>(values));
 
             _addActions.Add($"{nameKey} {valueKey}");
         }
@@ -686,8 +686,11 @@ public UpdateItemBuilder AddToNumberSet(string attributeName, params decimal[] v
             var nameKey = $"#n{_request.ExpressionAttributeNames.Count}";
             var valueKey = $":v{_request.ExpressionAttributeValues.Count}";
 
+            var numberStrings = new List<string>(values.Length);
+            foreach (var v in values)
+                numberStrings.Add(v.ToString(CultureInfo.InvariantCulture));
             _request.ExpressionAttributeNames[nameKey] = attributeName;
-            _request.ExpressionAttributeValues[valueKey] = AttributeValue.FromNumberSet(values.Select(v => v.ToString(CultureInfo.InvariantCulture)).ToList());
+            _request.ExpressionAttributeValues[valueKey] = AttributeValue.FromNumberSet(numberStrings);
 
             _addActions.Add($"{nameKey} {valueKey}");
         }
@@ -754,7 +757,7 @@ public UpdateItemBuilder RemoveFromStringSet(string attributeName, params string
             var valueKey = $":v{_request.ExpressionAttributeValues.Count}";
 
             _request.ExpressionAttributeNames[nameKey] = attributeName;
-            _request.ExpressionAttributeValues[valueKey] = AttributeValue.FromStringSet(values.ToList());
+            _request.ExpressionAttributeValues[valueKey] = AttributeValue.FromStringSet(new List<string>(values));
 
             _deleteActions.Add($"{nameKey} {valueKey}");
         }
@@ -777,8 +780,11 @@ public UpdateItemBuilder RemoveFromNumberSet(string attributeName, params decima
             var nameKey = $"#n{_request.ExpressionAttributeNames.Count}";
             var valueKey = $":v{_request.ExpressionAttributeValues.Count}";
 
+            var numberStrings = new List<string>(values.Length);
+            foreach (var v in values)
+                numberStrings.Add(v.ToString(CultureInfo.InvariantCulture));
             _request.ExpressionAttributeNames[nameKey] = attributeName;
-            _request.ExpressionAttributeValues[valueKey] = AttributeValue.FromNumberSet(values.Select(v => v.ToString(CultureInfo.InvariantCulture)).ToList());
+            _request.ExpressionAttributeValues[valueKey] = AttributeValue.FromNumberSet(numberStrings);
 
             _deleteActions.Add($"{nameKey} {valueKey}");
         }
@@ -919,8 +925,9 @@ private string BuildPathExpression(string path)
         var matches = PathSegmentRegex().Matches(path);
         var expressionParts = new List<string>();
 
-        foreach (Match match in matches)
+        for (var i = 0; i < matches.Count; i++)
         {
+            var match = matches[i];
             if (match.Groups[1].Success)
             {
                 // Attribute name
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/UpdateItem/UpdateItemRequest.cs b/src/Clients/Goa.Clients.Dynamo/Operations/UpdateItem/UpdateItemRequest.cs
index 7094d476..9d08dff9 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/UpdateItem/UpdateItemRequest.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/UpdateItem/UpdateItemRequest.cs
@@ -7,7 +7,7 @@ namespace Goa.Clients.Dynamo.Operations.UpdateItem;
 /// <summary>
 /// Request for updating an item in DynamoDB.
 /// </summary>
-public class UpdateItemRequest
+public sealed class UpdateItemRequest
 {
     /// <summary>
     /// The name of the table containing the item to update.
diff --git a/src/Clients/Goa.Clients.Dynamo/Operations/UpdateItem/UpdateItemResponse.cs b/src/Clients/Goa.Clients.Dynamo/Operations/UpdateItem/UpdateItemResponse.cs
index 330778fc..f16a0d42 100644
--- a/src/Clients/Goa.Clients.Dynamo/Operations/UpdateItem/UpdateItemResponse.cs
+++ b/src/Clients/Goa.Clients.Dynamo/Operations/UpdateItem/UpdateItemResponse.cs
@@ -6,7 +6,7 @@ namespace Goa.Clients.Dynamo.Operations.UpdateItem;
 /// <summary>
 /// Response for UpdateItem operations.
 /// </summary>
-public class UpdateItemResponse
+public sealed class UpdateItemResponse
 {
     /// <summary>
     /// A map of attribute names to AttributeValue objects representing the item as it appeared before it was updated.
diff --git a/src/Clients/Goa.Clients.Dynamo/SerializedNameAttribute.cs b/src/Clients/Goa.Clients.Dynamo/SerializedNameAttribute.cs
index 2df241fe..7a51ea56 100644
--- a/src/Clients/Goa.Clients.Dynamo/SerializedNameAttribute.cs
+++ b/src/Clients/Goa.Clients.Dynamo/SerializedNameAttribute.cs
@@ -5,7 +5,7 @@ namespace Goa.Clients.Dynamo;
 /// By default, property names are used as-is for DynamoDB attribute names.
 /// </summary>
 [AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
-public class SerializedNameAttribute : Attribute
+public sealed class SerializedNameAttribute : Attribute
 {
     /// <summary>
     /// Initializes a new instance of the SerializedNameAttribute class.
diff --git a/src/Clients/Goa.Clients.Dynamo/UnixTimestampAttribute.cs b/src/Clients/Goa.Clients.Dynamo/UnixTimestampAttribute.cs
index 37a0268e..a20f0701 100644
--- a/src/Clients/Goa.Clients.Dynamo/UnixTimestampAttribute.cs
+++ b/src/Clients/Goa.Clients.Dynamo/UnixTimestampAttribute.cs
@@ -6,7 +6,7 @@
 /// When used in composite PK/SK patterns, they are formatted as strings.
 /// </summary>
 [AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
-public class UnixTimestampAttribute : Attribute
+public sealed class UnixTimestampAttribute : Attribute
 {
     /// <summary>
     /// The format for the unix timestamp. Defaults to Seconds (AWS TTL compatible).
diff --git a/src/Clients/Goa.Clients.EventBridge/EventBridgeServiceClient.cs b/src/Clients/Goa.Clients.EventBridge/EventBridgeServiceClient.cs
index c7492305..ffffe185 100644
--- a/src/Clients/Goa.Clients.EventBridge/EventBridgeServiceClient.cs
+++ b/src/Clients/Goa.Clients.EventBridge/EventBridgeServiceClient.cs
@@ -47,7 +47,7 @@ public async Task<ErrorOr<PutEventsResponse>> PutEventsAsync(PutEventsRequest re
         }
         catch (Exception ex)
         {
-            Logger.LogError(ex, "Failed to put events to EventBridge");
+            Logger.PutEventsFailed(ex);
             return Error.Failure("EventBridge.PutEvents.Failed", "Failed to put events to EventBridge");
         }
     }
diff --git a/src/Clients/Goa.Clients.EventBridge/Log.cs b/src/Clients/Goa.Clients.EventBridge/Log.cs
new file mode 100644
index 00000000..17e0cbf3
--- /dev/null
+++ b/src/Clients/Goa.Clients.EventBridge/Log.cs
@@ -0,0 +1,9 @@
+using Microsoft.Extensions.Logging;
+
+namespace Goa.Clients.EventBridge;
+
+internal static partial class Log
+{
+    [LoggerMessage(EventId = 1, Level = LogLevel.Error, Message = "Failed to put events to EventBridge")]
+    public static partial void PutEventsFailed(this ILogger logger, Exception exception);
+}
diff --git a/src/Clients/Goa.Clients.Lambda/LambdaServiceClient.cs b/src/Clients/Goa.Clients.Lambda/LambdaServiceClient.cs
index bfc34192..6070892c 100644
--- a/src/Clients/Goa.Clients.Lambda/LambdaServiceClient.cs
+++ b/src/Clients/Goa.Clients.Lambda/LambdaServiceClient.cs
@@ -41,7 +41,12 @@ public async Task<ErrorOr<InvokeResponse>> InvokeSynchronousAsync(InvokeRequest
 
             // Add log type header
             if (request.LogType != LogType.None)
-                headers["X-Amz-Log-Type"] = request.LogType.ToString();
+                headers["X-Amz-Log-Type"] = request.LogType switch
+                {
+                    LogType.None => nameof(LogType.None),
+                    LogType.Tail => nameof(LogType.Tail),
+                    _ => throw new ArgumentOutOfRangeException(nameof(request.LogType), request.LogType, null)
+                };
 
             // Add client context header
             if (!string.IsNullOrWhiteSpace(request.ClientContext))
@@ -66,7 +71,7 @@ public async Task<ErrorOr<InvokeResponse>> InvokeSynchronousAsync(InvokeRequest
                 return ConvertApiError(response.Error!);
 
             // TODO: Lambda-specific headers (X-Amz-Function-Error, X-Amz-Log-Result, X-Amz-Executed-Version)
-            // are not captured by ResponseHeaders. Will be addressed when Lambda invoke is refactored
+            // are not captured. Will be addressed when Lambda invoke is refactored
             // to read directly from HttpResponseMessage.
             var invokeResponse = InvokeResponse.FromHttpResponse(
                 200,
@@ -77,7 +82,7 @@ public async Task<ErrorOr<InvokeResponse>> InvokeSynchronousAsync(InvokeRequest
         }
         catch (Exception ex)
         {
-            Logger.LogError(ex, "Failed to invoke Lambda function synchronously {FunctionName}", request.FunctionName);
+            Logger.InvokeSynchronousFailed(ex, request.FunctionName);
             return Error.Failure("Lambda.InvokeSynchronous.Failed", $"Failed to invoke Lambda function synchronously {request.FunctionName}");
         }
     }
@@ -125,7 +130,7 @@ public async Task<ErrorOr<InvokeAsyncResponse>> InvokeAsynchronousAsync(InvokeAs
         }
         catch (Exception ex)
         {
-            Logger.LogError(ex, "Failed to invoke Lambda function asynchronously {FunctionName}", request.FunctionName);
+            Logger.InvokeAsynchronousFailed(ex, request.FunctionName);
             return Error.Failure("Lambda.InvokeAsynchronous.Failed", $"Failed to invoke Lambda function asynchronously {request.FunctionName}");
         }
     }
@@ -173,7 +178,7 @@ public async Task<ErrorOr<InvokeDryRunResponse>> InvokeDryRunAsync(InvokeDryRunR
         }
         catch (Exception ex)
         {
-            Logger.LogError(ex, "Failed to dry run Lambda function {FunctionName}", request.FunctionName);
+            Logger.InvokeDryRunFailed(ex, request.FunctionName);
             return Error.Failure("Lambda.InvokeDryRun.Failed", $"Failed to dry run Lambda function {request.FunctionName}");
         }
     }
diff --git a/src/Clients/Goa.Clients.Lambda/Log.cs b/src/Clients/Goa.Clients.Lambda/Log.cs
new file mode 100644
index 00000000..c60e667f
--- /dev/null
+++ b/src/Clients/Goa.Clients.Lambda/Log.cs
@@ -0,0 +1,15 @@
+using Microsoft.Extensions.Logging;
+
+namespace Goa.Clients.Lambda;
+
+internal static partial class Log
+{
+    [LoggerMessage(EventId = 1, Level = LogLevel.Error, Message = "Failed to invoke Lambda function synchronously {FunctionName}")]
+    public static partial void InvokeSynchronousFailed(this ILogger logger, Exception exception, string functionName);
+
+    [LoggerMessage(EventId = 2, Level = LogLevel.Error, Message = "Failed to invoke Lambda function asynchronously {FunctionName}")]
+    public static partial void InvokeAsynchronousFailed(this ILogger logger, Exception exception, string functionName);
+
+    [LoggerMessage(EventId = 3, Level = LogLevel.Error, Message = "Failed to dry run Lambda function {FunctionName}")]
+    public static partial void InvokeDryRunFailed(this ILogger logger, Exception exception, string functionName);
+}
diff --git a/src/Clients/Goa.Clients.Lambda/Operations/Invoke/InvokeResponse.cs b/src/Clients/Goa.Clients.Lambda/Operations/Invoke/InvokeResponse.cs
index 9065ef7a..359cb0e3 100644
--- a/src/Clients/Goa.Clients.Lambda/Operations/Invoke/InvokeResponse.cs
+++ b/src/Clients/Goa.Clients.Lambda/Operations/Invoke/InvokeResponse.cs
@@ -57,11 +57,11 @@ public static InvokeResponse FromHttpResponse(int statusCode, string? payload, I
         if (headers != null)
         {
             if (headers.TryGetValue("X-Amz-Function-Error", out var functionError))
-                response.FunctionError = functionError.FirstOrDefault();
+                foreach (var v in functionError) { response.FunctionError = v; break; }
 
             if (headers.TryGetValue("X-Amz-Log-Result", out var logResult))
             {
-                response.LogResult = logResult.FirstOrDefault();
+                foreach (var v in logResult) { response.LogResult = v; break; }
                 if (!string.IsNullOrWhiteSpace(response.LogResult))
                 {
                     try
@@ -76,7 +76,7 @@ public static InvokeResponse FromHttpResponse(int statusCode, string? payload, I
             }
 
             if (headers.TryGetValue("X-Amz-Executed-Version", out var executedVersion))
-                response.ExecutedVersion = executedVersion.FirstOrDefault();
+                foreach (var v in executedVersion) { response.ExecutedVersion = v; break; }
         }
 
         return response;
diff --git a/src/Clients/Goa.Clients.Sns/Log.cs b/src/Clients/Goa.Clients.Sns/Log.cs
new file mode 100644
index 00000000..009ecfaa
--- /dev/null
+++ b/src/Clients/Goa.Clients.Sns/Log.cs
@@ -0,0 +1,12 @@
+using Microsoft.Extensions.Logging;
+
+namespace Goa.Clients.Sns;
+
+internal static partial class Log
+{
+    [LoggerMessage(EventId = 1, Level = LogLevel.Error, Message = "Failed to publish message to SNS target {Target}")]
+    public static partial void PublishFailed(this ILogger logger, Exception exception, string? target);
+
+    [LoggerMessage(EventId = 2, Level = LogLevel.Warning, Message = "Failed to deserialize SNS XML error response: {Content}")]
+    public static partial void DeserializeSnsErrorFailed(this ILogger logger, Exception exception, string content);
+}
diff --git a/src/Clients/Goa.Clients.Sns/SnsServiceClient.cs b/src/Clients/Goa.Clients.Sns/SnsServiceClient.cs
index 62d3be6e..e4ed858f 100644
--- a/src/Clients/Goa.Clients.Sns/SnsServiceClient.cs
+++ b/src/Clients/Goa.Clients.Sns/SnsServiceClient.cs
@@ -11,6 +11,7 @@ namespace Goa.Clients.Sns;
 
 internal sealed class SnsServiceClient : AwsServiceClient<SnsServiceClientConfiguration>, ISnsClient
 {
+    private static readonly MediaTypeHeaderValue FormUrlEncodedContentType = new("application/x-www-form-urlencoded");
     private static readonly ApiError DeserializationError = new("Failed to deserialize response", "DeserializationError");
 
     public SnsServiceClient(
@@ -47,20 +48,20 @@ public async Task<ErrorOr<PublishResponse>> PublishAsync(PublishRequest request,
                 HttpMethod.Post,
                 "/",
                 content,
-                new MediaTypeHeaderValue("application/x-www-form-urlencoded"));
+                FormUrlEncodedContentType);
 
             // Send request and get raw HTTP response
             var httpResponse = await SendAsync(requestMessage, "Publish", cancellationToken);
 
             // Process the response
-            var apiResponse = await ProcessSnsResponseAsync<PublishResponse>(httpResponse);
+            var apiResponse = await ProcessSnsResponseAsync<PublishResponse>(httpResponse, cancellationToken);
 
             return ConvertApiResponse(apiResponse);
         }
         catch (Exception ex)
         {
             var target = request.TopicArn ?? request.TargetArn ?? request.PhoneNumber;
-            Logger.LogError(ex, "Failed to publish message to SNS target {Target}", target);
+            Logger.PublishFailed(ex, target);
             return Error.Failure("SNS.Publish.Failed", $"Failed to publish message to SNS target {target}");
         }
     }
@@ -70,7 +71,7 @@ public async Task<ErrorOr<PublishResponse>> PublishAsync(PublishRequest request,
     /// </summary>
     private static string SerializeToQueryParameters(PublishRequest request)
     {
-        var parameters = new List<string>
+        var parameters = new List<string>(12)
         {
             "Action=Publish",
             "Version=2010-03-31"
@@ -126,20 +127,19 @@ private static string SerializeToQueryParameters(PublishRequest request)
     /// <summary>
     /// Processes an SNS HTTP response and converts it to an API response.
     /// </summary>
-    private async Task<ApiResponse<TResponse>> ProcessSnsResponseAsync<TResponse>(HttpResponseMessage response)
+    private async Task<ApiResponse<TResponse>> ProcessSnsResponseAsync<TResponse>(HttpResponseMessage response, CancellationToken cancellationToken)
         where TResponse : class, IDeserializeFromXml, new()
     {
-        var headers = ResponseHeaders.FromHttpResponse(response.Headers);
-
         if (!response.IsSuccessStatusCode)
         {
-            var errorPayload = await response.Content.ReadAsStringAsync();
-            if (string.IsNullOrWhiteSpace(errorPayload))
+            using var errorBuffer = await ReadResponseBytesAsync(response, cancellationToken);
+            if (errorBuffer.Length == 0)
             {
                 Logger.RequestFailed("No payload present");
                 return new ApiResponse<TResponse>(new ApiError("Request not successful.") { StatusCode = response.StatusCode });
             }
 
+            var errorPayload = Encoding.UTF8.GetString(errorBuffer.Span);
             var error = DeserializeSnsError(errorPayload);
             if (error is not null)
             {
@@ -161,46 +161,17 @@ private async Task<ApiResponse<TResponse>> ProcessSnsResponseAsync<TResponse>(Ht
             return new ApiResponse<TResponse>(error ?? DeserializationError);
         }
 
-        var contentPayload = await response.Content.ReadAsStringAsync();
+        using var pooledBuffer = await ReadResponseBytesAsync(response, cancellationToken);
+        var contentPayload = pooledBuffer.Length > 0 ? Encoding.UTF8.GetString(pooledBuffer.Span) : string.Empty;
 
         if (string.IsNullOrWhiteSpace(contentPayload))
         {
-            return new ApiResponse<TResponse>(default(TResponse), headers);
+            return new ApiResponse<TResponse>(default(TResponse));
         }
 
         var result = new TResponse();
         result.DeserializeFromXml(contentPayload);
-        return new ApiResponse<TResponse>(result, headers);
-    }
-
-    /// <summary>
-    /// Applies AWS-specific error header processing to the error object.
-    /// </summary>
-    private ApiError ProcessAwsErrorHeaders(HttpResponseMessage response, ApiError error)
-    {
-        if (response.Headers.TryGetValues(XAmznErrorMessage, out var messages))
-        {
-            error = error with { Message = string.Join(", ", messages) };
-        }
-
-        if (string.IsNullOrWhiteSpace(error.Type) && response.Headers.TryGetValues(XAmzErrorType, out var types))
-        {
-            error = error with { Type = string.Join(", ", types) };
-        }
-
-        var infoSeparator = error.Type?.LastIndexOf(':') ?? -1;
-        if (infoSeparator > 0)
-        {
-            error = error with { Type = error.Type![..infoSeparator] };
-        }
-
-        var typeSeparator = error.Type?.LastIndexOf('#') ?? -1;
-        if (typeSeparator > 0)
-        {
-            error = error with { Type = error.Type![(typeSeparator + 1)..] };
-        }
-
-        return error;
+        return new ApiResponse<TResponse>(result);
     }
 
     /// <summary>
@@ -219,7 +190,7 @@ private ApiError ProcessAwsErrorHeaders(HttpResponseMessage response, ApiError e
         }
         catch (Exception ex)
         {
-            Logger.LogWarning(ex, "Failed to deserialize SNS XML error response: {Content}", content);
+            Logger.DeserializeSnsErrorFailed(ex, content);
             return null;
         }
     }
diff --git a/src/Clients/Goa.Clients.Sqs/Log.cs b/src/Clients/Goa.Clients.Sqs/Log.cs
new file mode 100644
index 00000000..3e7f6ecd
--- /dev/null
+++ b/src/Clients/Goa.Clients.Sqs/Log.cs
@@ -0,0 +1,18 @@
+using Microsoft.Extensions.Logging;
+
+namespace Goa.Clients.Sqs;
+
+internal static partial class Log
+{
+    [LoggerMessage(EventId = 1, Level = LogLevel.Error, Message = "Failed to send message to SQS queue {QueueUrl}")]
+    public static partial void SendMessageFailed(this ILogger logger, Exception exception, string queueUrl);
+
+    [LoggerMessage(EventId = 2, Level = LogLevel.Error, Message = "Failed to send message batch to SQS queue {QueueUrl}")]
+    public static partial void SendMessageBatchFailed(this ILogger logger, Exception exception, string queueUrl);
+
+    [LoggerMessage(EventId = 3, Level = LogLevel.Error, Message = "Failed to receive messages from SQS queue {QueueUrl}")]
+    public static partial void ReceiveMessageFailed(this ILogger logger, Exception exception, string queueUrl);
+
+    [LoggerMessage(EventId = 4, Level = LogLevel.Error, Message = "Failed to delete message from SQS queue {QueueUrl}")]
+    public static partial void DeleteMessageFailed(this ILogger logger, Exception exception, string queueUrl);
+}
diff --git a/src/Clients/Goa.Clients.Sqs/SqsExtensions.cs b/src/Clients/Goa.Clients.Sqs/SqsExtensions.cs
index dc19c88e..b02be14a 100644
--- a/src/Clients/Goa.Clients.Sqs/SqsExtensions.cs
+++ b/src/Clients/Goa.Clients.Sqs/SqsExtensions.cs
@@ -127,7 +127,9 @@ private static async Task<ErrorOr<SendMessageBatchAggregatedResponse>> SendBatch
         }
 
         // Chunk into batches of 10
-        var chunks = entries.Chunk(MaxBatchSize).ToList();
+        var chunkCount = (entries.Count + MaxBatchSize - 1) / MaxBatchSize;
+        var chunks = new List<SendMessageBatchRequestEntry[]>(chunkCount);
+        chunks.AddRange(entries.Chunk(MaxBatchSize));
 
         // Create batch requests
         var batchTasks = chunks.Select((chunk, batchIndex) =>
diff --git a/src/Clients/Goa.Clients.Sqs/SqsServiceClient.cs b/src/Clients/Goa.Clients.Sqs/SqsServiceClient.cs
index 385e6793..bbe16a5e 100644
--- a/src/Clients/Goa.Clients.Sqs/SqsServiceClient.cs
+++ b/src/Clients/Goa.Clients.Sqs/SqsServiceClient.cs
@@ -50,7 +50,7 @@ public async Task<ErrorOr<SendMessageResponse>> SendMessageAsync(SendMessageRequ
         }
         catch (Exception ex)
         {
-            Logger.LogError(ex, "Failed to send message to SQS queue {QueueUrl}", request.QueueUrl);
+            Logger.SendMessageFailed(ex, request.QueueUrl);
             return Error.Failure("SQS.SendMessage.Failed", $"Failed to send message to SQS queue {request.QueueUrl}");
         }
     }
@@ -90,7 +90,7 @@ public async Task<ErrorOr<SendMessageBatchResponse>> SendMessageBatchAsync(SendM
         }
         catch (Exception ex)
         {
-            Logger.LogError(ex, "Failed to send message batch to SQS queue {QueueUrl}", request.QueueUrl);
+            Logger.SendMessageBatchFailed(ex, request.QueueUrl);
             return Error.Failure("SQS.SendMessageBatch.Failed", $"Failed to send message batch to SQS queue {request.QueueUrl}");
         }
     }
@@ -118,7 +118,7 @@ public async Task<ErrorOr<ReceiveMessageResponse>> ReceiveMessageAsync(ReceiveMe
         }
         catch (Exception ex)
         {
-            Logger.LogError(ex, "Failed to receive messages from SQS queue {QueueUrl}", request.QueueUrl);
+            Logger.ReceiveMessageFailed(ex, request.QueueUrl);
             return Error.Failure("SQS.ReceiveMessage.Failed", $"Failed to receive messages from SQS queue {request.QueueUrl}");
         }
     }
@@ -146,7 +146,7 @@ public async Task<ErrorOr<DeleteMessageResponse>> DeleteMessageAsync(DeleteMessa
         }
         catch (Exception ex)
         {
-            Logger.LogError(ex, "Failed to delete message from SQS queue {QueueUrl}", request.QueueUrl);
+            Logger.DeleteMessageFailed(ex, request.QueueUrl);
             return Error.Failure("SQS.DeleteMessage.Failed", $"Failed to delete message from SQS queue {request.QueueUrl}");
         }
     }
diff --git a/src/Functions/Goa.Functions.ApiGateway/Features/V1/LambdaHttpRequestFeatureV1.cs b/src/Functions/Goa.Functions.ApiGateway/Features/V1/LambdaHttpRequestFeatureV1.cs
index 876dd40b..1093fc35 100644
--- a/src/Functions/Goa.Functions.ApiGateway/Features/V1/LambdaHttpRequestFeatureV1.cs
+++ b/src/Functions/Goa.Functions.ApiGateway/Features/V1/LambdaHttpRequestFeatureV1.cs
@@ -29,7 +29,19 @@ public LambdaHttpRequestFeatureV1(ProxyPayloadV1Request request)
     private static string BuildQueryString(IDictionary<string, string>? queryStringParameters)
     {
         if (queryStringParameters == null || queryStringParameters.Count == 0) return string.Empty;
-        return "?" + string.Join("&", queryStringParameters.Select(kvp => $"{Uri.EscapeDataString(kvp.Key)}={Uri.EscapeDataString(kvp.Value)}"));
+
+        var sb = new StringBuilder("?");
+        var first = true;
+        foreach (var kvp in queryStringParameters)
+        {
+            if (!first)
+                sb.Append('&');
+            sb.Append(Uri.EscapeDataString(kvp.Key));
+            sb.Append('=');
+            sb.Append(Uri.EscapeDataString(kvp.Value));
+            first = false;
+        }
+        return sb.ToString();
     }
 
     private static IHeaderDictionary BuildHeaderDictionary(IDictionary<string, string>? headers, IDictionary<string, IList<string>>? multiValueHeaders)
diff --git a/src/Functions/Goa.Functions.ApiGateway/Features/V2/LambdaHttpAuthenticationFeatureV2.cs b/src/Functions/Goa.Functions.ApiGateway/Features/V2/LambdaHttpAuthenticationFeatureV2.cs
index 78633dd4..c4850c3a 100644
--- a/src/Functions/Goa.Functions.ApiGateway/Features/V2/LambdaHttpAuthenticationFeatureV2.cs
+++ b/src/Functions/Goa.Functions.ApiGateway/Features/V2/LambdaHttpAuthenticationFeatureV2.cs
@@ -30,11 +30,10 @@ public LambdaHttpAuthenticationFeatureV2(ProxyPayloadV2RequestAuthentication? au
 
         if (authorizer?.Jwt?.Claims != null)
         {
-            // Use the authorizer's JWT claims to build the ClaimsPrincipal
-            User = new ClaimsPrincipal(new ClaimsIdentity(
-                claims.Concat(authorizer.Jwt.Claims.Select(kvp => new Claim(kvp.Key, kvp.Value))),
-                "Jwt"
-            ));
+            foreach (var kvp in authorizer.Jwt.Claims)
+                claims.Add(new Claim(kvp.Key, kvp.Value));
+
+            User = new ClaimsPrincipal(new ClaimsIdentity(claims, "Jwt"));
         }
         else if (authorizer?.IAM is not null)
         {
@@ -48,13 +47,10 @@ public LambdaHttpAuthenticationFeatureV2(ProxyPayloadV2RequestAuthentication? au
         }
         else if (authentication?.ClientCert != null)
         {
-            // Fallback to client certificate details
-            User = new ClaimsPrincipal(new ClaimsIdentity(claims.Concat(new[]
-            {
-                new Claim(ClaimTypes.Name, authentication.ClientCert.SubjectDN ?? "Anonymous"),
-                new Claim("Issuer", authentication.ClientCert.IssuerDN ?? string.Empty),
-                new Claim("SerialNumber", authentication.ClientCert.SerialNumber ?? string.Empty)
-            }), "ClientCert"));
+            claims.Add(new Claim(ClaimTypes.Name, authentication.ClientCert.SubjectDN ?? "Anonymous"));
+            claims.Add(new Claim("Issuer", authentication.ClientCert.IssuerDN ?? string.Empty));
+            claims.Add(new Claim("SerialNumber", authentication.ClientCert.SerialNumber ?? string.Empty));
+            User = new ClaimsPrincipal(new ClaimsIdentity(claims, "ClientCert"));
         }
         else
         {
@@ -74,11 +70,20 @@ private ClaimsPrincipal DecodeJwtToClaimsPrincipal(string jwt, List<Claim> claim
 
         var token = handler.ReadJwtToken(jwt);
 
-        // Create claims from JWT payload
-        claims.AddRange(token.Claims.ToList());
+        claims.AddRange(token.Claims);
 
         // Optionally add the token's subject as a Name claim if it exists
-        if (!string.IsNullOrEmpty(token.Subject) && claims.All(c => c.Type != ClaimTypes.NameIdentifier))
+        var hasNameIdentifier = false;
+        foreach (var c in claims)
+        {
+            if (c.Type == ClaimTypes.NameIdentifier)
+            {
+                hasNameIdentifier = true;
+                break;
+            }
+        }
+
+        if (!string.IsNullOrEmpty(token.Subject) && !hasNameIdentifier)
         {
             claims.Add(new Claim(ClaimTypes.NameIdentifier, token.Subject));
         }
diff --git a/src/Functions/Goa.Functions.Core/Bootstrapping/LambdaRuntimeClient.cs b/src/Functions/Goa.Functions.Core/Bootstrapping/LambdaRuntimeClient.cs
index 52dd14f2..b5709b23 100644
--- a/src/Functions/Goa.Functions.Core/Bootstrapping/LambdaRuntimeClient.cs
+++ b/src/Functions/Goa.Functions.Core/Bootstrapping/LambdaRuntimeClient.cs
@@ -45,15 +45,18 @@ public async Task<Result<InvocationRequest>> GetNextInvocationAsync(Cancellation
 
             if (response.Headers.TryGetValues("Lambda-Runtime-Aws-Request-Id", out var requestIdValues))
             {
-                requestId = requestIdValues.FirstOrDefault() ?? string.Empty;
+                requestId = string.Empty;
+                foreach (var v in requestIdValues) { requestId = v; break; }
             }
             if (response.Headers.TryGetValues("Lambda-Runtime-Deadline-Ms", out var deadlineMsValues))
             {
-                deadlineMs = deadlineMsValues.FirstOrDefault() ?? string.Empty;
+                deadlineMs = string.Empty;
+                foreach (var v in deadlineMsValues) { deadlineMs = v; break; }
             }
             if (response.Headers.TryGetValues("Lambda-Runtime-Invoked-Function-Arn", out var functionArnValues))
             {
-                functionArn = functionArnValues.FirstOrDefault() ?? string.Empty;
+                functionArn = string.Empty;
+                foreach (var v in functionArnValues) { functionArn = v; break; }
             }
 
             var payload = await response.Content.ReadAsStringAsync(cancellationToken);
diff --git a/src/Functions/Goa.Functions.Core/Logging/JsonLogger.cs b/src/Functions/Goa.Functions.Core/Logging/JsonLogger.cs
index 08eacdbf..868b5108 100644
--- a/src/Functions/Goa.Functions.Core/Logging/JsonLogger.cs
+++ b/src/Functions/Goa.Functions.Core/Logging/JsonLogger.cs
@@ -120,11 +120,11 @@ private static void WriteScopeInformation(Dictionary<string, object> data, IExte
             }
             else if (scope is KeyValuePair<string, string> kvp)
             {
-                data[kvp.Key] = kvp.Value;
+                state[kvp.Key] = kvp.Value;
             }
             else if (scope is not null)
             {
-                data[FieldState] = scope;
+                state[FieldState] = scope;
             }
         }, data);
     }
diff --git a/src/Goa.Core/CollectionExtensions.cs b/src/Goa.Core/CollectionExtensions.cs
index bf2d48e6..7891eb50 100644
--- a/src/Goa.Core/CollectionExtensions.cs
+++ b/src/Goa.Core/CollectionExtensions.cs
@@ -22,7 +22,9 @@ public static IReadOnlyDictionary<TKey, TValue> Merge<TDictionary, TKey, TValue>
     {
         if (source is not Dictionary<TKey, TValue> result)
         {
-            result = new Dictionary<TKey, TValue>(source);
+            result = new Dictionary<TKey, TValue>(source.Count);
+            foreach (var (key, value) in source)
+                result[key] = value;
         }
 
         foreach (var (key, value) in items)
diff --git a/src/Goa.Core/LoggerExtensions.cs b/src/Goa.Core/LoggerExtensions.cs
index 8f2ef32a..f2094bef 100644
--- a/src/Goa.Core/LoggerExtensions.cs
+++ b/src/Goa.Core/LoggerExtensions.cs
@@ -5,7 +5,7 @@ namespace Goa.Core;
 /// <summary>
 ///     Extends all ILogger instances with commonly used extension methods
 /// </summary>
-public static class LoggerExtensions
+public static partial class LoggerExtensions
 {
     /// <summary>
     ///     Attaches a series of values to the context, using a Microsoft.Extensions.Logging compatible approach
@@ -17,7 +17,15 @@ public static class LoggerExtensions
         if (values.Length == 0)
             return null;
 
-        return logger.BeginScope(values.ToDictionary(x => x.Key, x => (object)x.Value!));
+        var dict = new Dictionary<string, object>(values.Length);
+        foreach (var kv in values)
+        {
+            // Boxing T→object is unavoidable: ILogger.BeginScope requires IDictionary<string, object>
+#pragma warning disable GOA1501
+            dict[kv.Key] = kv.Value!;
+#pragma warning restore GOA1501
+        }
+        return logger.BeginScope(dict);
     }
 
     /// <summary>
@@ -30,7 +38,15 @@ public static class LoggerExtensions
         if (values.Length == 0)
             return null;
 
-        return logger.BeginScope(values.ToDictionary(x => x.key, x => (object)x.value!));
+        var dict = new Dictionary<string, object>(values.Length);
+        foreach (var (key, value) in values)
+        {
+            // Boxing T→object is unavoidable: ILogger.BeginScope requires IDictionary<string, object>
+#pragma warning disable GOA1501
+            dict[key] = value!;
+#pragma warning restore GOA1501
+        }
+        return logger.BeginScope(dict);
     }
 
     /// <summary>
@@ -44,12 +60,21 @@ public static class LoggerExtensions
         if (string.IsNullOrWhiteSpace(key))
             return null;
 
+        // Boxing T→object is unavoidable: ILogger.BeginScope requires IDictionary<string, object>
+#pragma warning disable GOA1501
         return logger.BeginScope(new Dictionary<string, object>
         {
             [key] = value!
         });
+#pragma warning restore GOA1501
     }
 
+    [LoggerMessage(EventId = 0, Level = LogLevel.Critical, Message = "{ExceptionMessage}")]
+    private static partial void LogExceptionCritical(this ILogger logger, string? exceptionMessage);
+
+    [LoggerMessage(EventId = 0, Level = LogLevel.Error, Message = "{ExceptionMessage}")]
+    private static partial void LogExceptionError(this ILogger logger, string? exceptionMessage);
+
     /// <summary>
     ///     Helper to log an exception when there is no specific message associated with it
     /// </summary>
@@ -59,12 +84,12 @@ public static class LoggerExtensions
     /// <typeparam name="T">The type of the exception thrown</typeparam>
     public static void LogException<T>(this ILogger logger, T exception, bool critical = false) where T : Exception
     {
-        using var scope = logger.WithContext(new [] { ("Exception:Type", exception.GetType().FullName ), ("Exception:StackTrace", exception.StackTrace ) });
-#pragma warning disable CA2254
+#pragma warning disable GOA1401 // Explicit array required for params overload
+        using var scope = logger.WithContext(new KeyValuePair<string, string?>[] { new("Exception:Type", exception.GetType().FullName), new("Exception:StackTrace", exception.StackTrace) });
+#pragma warning restore GOA1401
         if (critical)
-            logger.LogCritical(exception.Message);
+            logger.LogExceptionCritical(exception.Message);
         else
-            logger.LogError(exception.Message);
-#pragma warning restore CA2254
+            logger.LogExceptionError(exception.Message);
     }
 }
diff --git a/tests/Clients/Goa.Clients.Dynamo.Benchmarks/Benchmarks/QueryAsyncBenchmarks.cs b/tests/Clients/Goa.Clients.Dynamo.Benchmarks/Benchmarks/QueryAsyncBenchmarks.cs
index 194ca5e8..1debe643 100644
--- a/tests/Clients/Goa.Clients.Dynamo.Benchmarks/Benchmarks/QueryAsyncBenchmarks.cs
+++ b/tests/Clients/Goa.Clients.Dynamo.Benchmarks/Benchmarks/QueryAsyncBenchmarks.cs
@@ -40,6 +40,8 @@ public class QueryAsyncBenchmarks
     [GlobalSetup]
     public void Setup()
     {
+        DynamoReaderRegistration.Initialize();
+
         _fixture = new LocalStackFixture();
         _fixture.StartAsync().GetAwaiter().GetResult();
 
diff --git a/tests/Clients/Goa.Clients.Dynamo.Generator.Tests/CodeGeneration/MapperGeneratorTests.cs b/tests/Clients/Goa.Clients.Dynamo.Generator.Tests/CodeGeneration/MapperGeneratorTests.cs
index 01f08637..8e85b24b 100644
--- a/tests/Clients/Goa.Clients.Dynamo.Generator.Tests/CodeGeneration/MapperGeneratorTests.cs
+++ b/tests/Clients/Goa.Clients.Dynamo.Generator.Tests/CodeGeneration/MapperGeneratorTests.cs
@@ -602,7 +602,7 @@ await Assert.That(result)
         await Assert.That(result)
             .Contains("TestNamespace.ConcreteEntity concrete => DynamoMapper.ConcreteEntity.ToDynamoRecord(concrete),");
         await Assert.That(result)
-            .Contains("_ => throw new InvalidOperationException($\"Unknown concrete type: {model.GetType().FullName} for abstract type TestNamespace.BaseEntity\")");
+            .Contains("_ => Throw.InvalidOperation<DynamoRecord>($\"Unknown concrete type: {model.GetType().FullName} for abstract type TestNamespace.BaseEntity\")");
     }
 
     private static TypeHandlerRegistry CreateTypeHandlerRegistry()