diff --git a/README.md b/README.md
index c0e6809..fb08872 100644
--- a/README.md
+++ b/README.md
@@ -31,6 +31,8 @@ let req = ChatCompletionRequest::new(
         role: chat_completion::MessageRole::user,
         content: chat_completion::Content::Text(String::from("What is bitcoin?")),
         name: None,
+        tool_calls: None,
+        tool_call_id: None,
     }],
 );
 ```
diff --git a/examples/chat_completion.rs b/examples/chat_completion.rs
index d53134f..7a31241 100644
--- a/examples/chat_completion.rs
+++ b/examples/chat_completion.rs
@@ -13,6 +13,8 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
             role: chat_completion::MessageRole::user,
             content: chat_completion::Content::Text(String::from("What is bitcoin?")),
             name: None,
+            tool_calls: None,
+            tool_call_id: None,
         }],
     );
 
diff --git a/examples/function_call.rs b/examples/function_call.rs
index 27c6375..ddf1d3d 100644
--- a/examples/function_call.rs
+++ b/examples/function_call.rs
@@ -34,6 +34,8 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
             role: chat_completion::MessageRole::user,
             content: chat_completion::Content::Text(String::from("What is the price of Ethereum?")),
             name: None,
+            tool_calls: None,
+            tool_call_id: None,
         }],
     )
     .tools(vec![chat_completion::Tool {
diff --git a/examples/function_call_role.rs b/examples/function_call_role.rs
index dcdf7ad..38463a5 100644
--- a/examples/function_call_role.rs
+++ b/examples/function_call_role.rs
@@ -34,6 +34,8 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
             role: chat_completion::MessageRole::user,
             content: chat_completion::Content::Text(String::from("What is the price of Ethereum?")),
             name: None,
+            tool_calls: None,
+            tool_call_id: None,
         }],
     )
     .tools(vec![chat_completion::Tool {
@@ -88,6 +90,8 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
                                 "What is the price of Ethereum?",
                             )),
                             name: None,
+                            tool_calls: None,
+                            tool_call_id: None,
                         },
                         chat_completion::ChatCompletionMessage {
                             role: chat_completion::MessageRole::function,
@@ -96,6 +100,8 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
                                 format!("{{\"price\": {}}}", price)
                             }),
                             name: Some(String::from("get_coin_price")),
+                            tool_calls: None,
+                            tool_call_id: None,
                         },
                     ],
                 );
diff --git a/examples/vision.rs b/examples/vision.rs
index b62a653..57397ae 100644
--- a/examples/vision.rs
+++ b/examples/vision.rs
@@ -28,6 +28,8 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
                 },
             ]),
             name: None,
+            tool_calls: None,
+            tool_call_id: None,
         }],
     );
 
diff --git a/src/v1/chat_completion.rs b/src/v1/chat_completion.rs
index 0a551ae..28284be 100644
--- a/src/v1/chat_completion.rs
+++ b/src/v1/chat_completion.rs
@@ -45,6 +45,8 @@ pub struct ChatCompletionRequest {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub tools: Option<Vec<Tool>>,
     #[serde(skip_serializing_if = "Option::is_none")]
+    pub parallel_tool_calls: Option<bool>,
+    #[serde(skip_serializing_if = "Option::is_none")]
     #[serde(serialize_with = "serialize_tool_choice")]
     pub tool_choice: Option<ToolChoiceType>,
 }
@@ -67,6 +69,7 @@ impl ChatCompletionRequest {
             user: None,
             seed: None,
             tools: None,
+            parallel_tool_calls: None,
             tool_choice: None,
         }
     }
@@ -87,6 +90,7 @@ impl_builder_methods!(
     user: String,
     seed: i64,
     tools: Vec<Tool>,
+    parallel_tool_calls: bool,
     tool_choice: ToolChoiceType
 );
 
@@ -97,6 +101,7 @@ pub enum MessageRole {
     system,
     assistant,
     function,
+    tool,
 }
 
 #[derive(Debug, Deserialize, Clone, PartialEq, Eq)]
@@ -111,7 +116,13 @@ impl serde::Serialize for Content {
         S: serde::Serializer,
     {
         match *self {
-            Content::Text(ref text) => serializer.serialize_str(text),
+            Content::Text(ref text) => {
+                if text.is_empty() {
+                    serializer.serialize_none()
+                } else {
+                    serializer.serialize_str(text)
+                }
+            }
             Content::ImageUrl(ref image_url) => image_url.serialize(serializer),
         }
     }
@@ -146,6 +157,10 @@ pub struct ChatCompletionMessage {
     pub content: Content,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub name: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub tool_calls: Option<Vec<ToolCall>>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub tool_call_id: Option<String>,
 }
 
 #[derive(Debug, Deserialize, Serialize)]