diff --git a/src/AnthropicClient/Models/BaseMessageRequest.cs b/src/AnthropicClient/Models/BaseMessageRequest.cs
index fb5413b..040f743 100644
--- a/src/AnthropicClient/Models/BaseMessageRequest.cs
+++ b/src/AnthropicClient/Models/BaseMessageRequest.cs
@@ -14,6 +14,11 @@ public abstract class BaseMessageRequest
   /// </summary>
   public string Model { get; init; } = string.Empty;
 
+  // TODO: I do not like this. I would prefer to have a single property that is a list of TextContent objects.
+  // This approach was taken to maintain compatibility with the API. As someone could be using the System property
+  // and changing it to a list of TextContent objects would break their code.
+  // However if an opportunity arises for a breaking change release, this should be changed.
+
   /// <summary>
   /// Gets the system message that will be used as the system prompt if no system messages are provided.
   /// </summary>
@@ -105,12 +110,33 @@ public abstract class BaseMessageRequest
   [JsonConstructor]
   internal BaseMessageRequest() { }
   
-  private BaseMessageRequest(
+  /// <summary>
+  /// Initializes a new instance of the <see cref="BaseMessageRequest"/> class.
+  /// </summary>
+  /// <param name="model">The model ID to use for the request.</param>
+  /// <param name="messages">The messages to send to the model.</param>
+  /// <param name="maxTokens">The maximum number of tokens to generate.</param>
+  /// <param name="system">The system prompt to use for the request.</param>
+  /// <param name="metadata">The metadata to include with the request.</param>
+  /// <param name="temperature">The temperature to use for the request.</param>
+  /// <param name="topK">The top-K value to use for the request.</param>
+  /// <param name="topP">The top-P value to use for the request.</param>
+  /// <param name="toolChoice">The tool choice mode to use for the request.</param>
+  /// <param name="tools">The tools to use for the request.</param>
+  /// <param name="stream">A value indicating whether the message should be streamed.</param>
+  /// <param name="stopSequences">The prompt stop sequences.</param>
+  /// <param name="systemMessages">The system messages to use for the request.</param>
+  /// <exception cref="ArgumentException">Thrown when the model ID is invalid.</exception>
+  /// <exception cref="ArgumentNullException">Thrown when the model or messages is null.</exception>
+  /// <exception cref="ArgumentException">Thrown when the messages contain no messages.</exception>
+  /// <exception cref="ArgumentException">Thrown when the max tokens is less than one.</exception>
+  /// <exception cref="ArgumentException">Thrown when the temperature is less than zero or greater than one.</exception>
+  /// <returns>A new instance of the <see cref="BaseMessageRequest"/> class.</returns>
+  protected BaseMessageRequest(
     string model,
     List<Message> messages,
     int maxTokens,
     string? system,
-    List<TextContent>? systemMessages,
     Dictionary<string, object>? metadata,
     decimal temperature,
     int? topK,
@@ -118,7 +144,8 @@ public abstract class BaseMessageRequest
     ToolChoice? toolChoice,
     List<Tool>? tools,
     bool stream,
-    List<string>? stopSequences
+    List<string>? stopSequences,
+    List<TextContent>? systemMessages
   )
   {
     ArgumentValidator.ThrowIfNull(model, nameof(model));
@@ -158,108 +185,4 @@ public abstract class BaseMessageRequest
     Stream = stream;
     StopSequences = stopSequences ?? [];
   }
-
-  /// <summary>
-  /// Initializes a new instance of the <see cref="BaseMessageRequest"/> class.
-  /// </summary>
-  /// <param name="model">The model ID to use for the request.</param>
-  /// <param name="messages">The messages to send to the model.</param>
-  /// <param name="maxTokens">The maximum number of tokens to generate.</param>
-  /// <param name="system">The system prompt to use for the request.</param>
-  /// <param name="metadata">The metadata to include with the request.</param>
-  /// <param name="temperature">The temperature to use for the request.</param>
-  /// <param name="topK">The top-K value to use for the request.</param>
-  /// <param name="topP">The top-P value to use for the request.</param>
-  /// <param name="toolChoice">The tool choice mode to use for the request.</param>
-  /// <param name="tools">The tools to use for the request.</param>
-  /// <param name="stream">A value indicating whether the message should be streamed.</param>
-  /// <param name="stopSequences">The prompt stop sequences.</param>
-  /// <exception cref="ArgumentException">Thrown when the model ID is invalid.</exception>
-  /// <exception cref="ArgumentNullException">Thrown when the model or messages is null.</exception>
-  /// <exception cref="ArgumentException">Thrown when the messages contain no messages.</exception>
-  /// <exception cref="ArgumentException">Thrown when the max tokens is less than one.</exception>
-  /// <exception cref="ArgumentException">Thrown when the temperature is less than zero or greater than one.</exception>
-  /// <returns>A new instance of the <see cref="BaseMessageRequest"/> class.</returns>
-  protected BaseMessageRequest(
-    string model,
-    List<Message> messages,
-    int maxTokens = 1024,
-    string? system = null,
-    Dictionary<string, object>? metadata = null,
-    decimal temperature = 0.0m,
-    int? topK = null,
-    decimal? topP = null,
-    ToolChoice? toolChoice = null,
-    List<Tool>? tools = null,
-    bool stream = false,
-    List<string>? stopSequences = null
-  ) : this(
-    model,
-    messages,
-    maxTokens,
-    system,
-    null,
-    metadata,
-    temperature,
-    topK,
-    topP,
-    toolChoice,
-    tools,
-    stream,
-    stopSequences
-  )
-  {
-  }
-
-  /// <summary>
-  /// Initializes a new instance of the <see cref="BaseMessageRequest"/> class.
-  /// </summary>
-  /// <param name="model">The model ID to use for the request.</param>
-  /// <param name="messages">The messages to send to the model.</param>
-  /// <param name="maxTokens">The maximum number of tokens to generate.</param>
-  /// <param name="systemMessages">The system messages to send to the model to be used as the system prompt.</param>
-  /// <param name="metadata">The metadata to include with the request.</param>
-  /// <param name="temperature">The temperature to use for the request.</param>
-  /// <param name="topK">The top-K value to use for the request.</param>
-  /// <param name="topP">The top-P value to use for the request.</param>
-  /// <param name="toolChoice">The tool choice mode to use for the request.</param>
-  /// <param name="tools">The tools to use for the request.</param>
-  /// <param name="stream">A value indicating whether the message should be streamed.</param>
-  /// <param name="stopSequences">The prompt stop sequences.</param>
-  /// <exception cref="ArgumentException">Thrown when the model ID is invalid.</exception>
-  /// <exception cref="ArgumentNullException">Thrown when the model or messages is null.</exception>
-  /// <exception cref="ArgumentException">Thrown when the messages contain no messages.</exception>
-  /// <exception cref="ArgumentException">Thrown when the max tokens is less than one.</exception>
-  /// <exception cref="ArgumentException">Thrown when the temperature is less than zero or greater than one.</exception>
-  /// <returns>A new instance of the <see cref="BaseMessageRequest"/> class.</returns>
-  protected BaseMessageRequest(
-    string model,
-    List<Message> messages,
-    int maxTokens = 1024,
-    List<TextContent>? systemMessages = null,
-    Dictionary<string, object>? metadata = null,
-    decimal temperature = 0.0m,
-    int? topK = null,
-    decimal? topP = null,
-    ToolChoice? toolChoice = null,
-    List<Tool>? tools = null,
-    bool stream = false,
-    List<string>? stopSequences = null
-  ) : this(
-    model,
-    messages,
-    maxTokens,
-    null,
-    systemMessages,
-    metadata,
-    temperature,
-    topK,
-    topP,
-    toolChoice,
-    tools,
-    stream,
-    stopSequences
-  )
-  {
-  }
 }
\ No newline at end of file
diff --git a/src/AnthropicClient/Models/MessageRequest.cs b/src/AnthropicClient/Models/MessageRequest.cs
index fab7af1..f091dbf 100644
--- a/src/AnthropicClient/Models/MessageRequest.cs
+++ b/src/AnthropicClient/Models/MessageRequest.cs
@@ -16,7 +16,7 @@ public class MessageRequest : BaseMessageRequest
   /// <param name="model">The model ID to use for the request.</param>
   /// <param name="messages">The messages to send to the model.</param>
   /// <param name="maxTokens">The maximum number of tokens to generate.</param>
-  /// <param name="system">The system ID to use for the request.</param>
+  /// <param name="system">The system prompt to use for the request.</param>
   /// <param name="metadata">The metadata to include with the request.</param>
   /// <param name="temperature">The temperature to use for the request.</param>
   /// <param name="topK">The top-K value to use for the request.</param>
@@ -24,6 +24,7 @@ public class MessageRequest : BaseMessageRequest
   /// <param name="toolChoice">The tool choice mode to use for the request.</param>
   /// <param name="tools">The tools to use for the request.</param>
   /// <param name="stopSequences">The prompt stop sequences.</param>
+  /// <param name="systemMessages">The system messages to include with the request.</param>
   /// <exception cref="ArgumentException">Thrown when the model ID is invalid.</exception>
   /// <exception cref="ArgumentNullException">Thrown when the model or messages is null.</exception>
   /// <exception cref="ArgumentException">Thrown when the messages contain no messages.</exception>
@@ -41,7 +42,8 @@ public class MessageRequest : BaseMessageRequest
     decimal? topP = null,
     ToolChoice? toolChoice = null,
     List<Tool>? tools = null,
-    List<string>? stopSequences = null
+    List<string>? stopSequences = null,
+    List<TextContent>? systemMessages = null
   ) : base(
     model,
     messages,
@@ -54,7 +56,8 @@ public class MessageRequest : BaseMessageRequest
     toolChoice,
     tools,
     false,
-    stopSequences
+    stopSequences,
+    systemMessages
   )
   {
   }
diff --git a/src/AnthropicClient/Models/StreamMessageRequest.cs b/src/AnthropicClient/Models/StreamMessageRequest.cs
index 9ef0e0b..402075e 100644
--- a/src/AnthropicClient/Models/StreamMessageRequest.cs
+++ b/src/AnthropicClient/Models/StreamMessageRequest.cs
@@ -16,7 +16,7 @@ public class StreamMessageRequest : BaseMessageRequest
   /// <param name="model">The model ID to use for the request.</param>
   /// <param name="messages">The messages to send to the model.</param>
   /// <param name="maxTokens">The maximum number of tokens to generate.</param>
-  /// <param name="system">The system ID to use for the request.</param>
+  /// <param name="system">The system prompt to use for the request.</param>
   /// <param name="metadata">The metadata to include with the request.</param>
   /// <param name="temperature">The temperature to use for the request.</param>
   /// <param name="topK">The top-K value to use for the request.</param>
@@ -24,6 +24,7 @@ public class StreamMessageRequest : BaseMessageRequest
   /// <param name="toolChoice">The tool choice mode to use for the request.</param>
   /// <param name="tools">The tools to use for the request.</param>
   /// <param name="stopSequences">The prompt stop sequences.</param>
+  /// <param name="systemMessages">The system messages to include with the request.</param>
   /// <exception cref="ArgumentException">Thrown when the model ID is invalid.</exception>
   /// <exception cref="ArgumentNullException">Thrown when the model or messages is null.</exception>
   /// <exception cref="ArgumentException">Thrown when the messages contain no messages.</exception>
@@ -41,7 +42,8 @@ public class StreamMessageRequest : BaseMessageRequest
     decimal? topP = null,
     ToolChoice? toolChoice = null,
     List<Tool>? tools = null,
-    List<string>? stopSequences = null
+    List<string>? stopSequences = null,
+    List<TextContent>? systemMessages = null
   ) : base(
     model,
     messages,
@@ -54,7 +56,8 @@ public class StreamMessageRequest : BaseMessageRequest
     toolChoice,
     tools,
     true,
-    stopSequences
+    stopSequences,
+    systemMessages
   )
   {
   }