Cross Cutting Performance Improvements

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
@@ -212,18 +212,18 @@ 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(
         string conversationId,
         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)

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.

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,

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)

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.