diff --git a/README.md b/README.md
index cf440d4..fb08872 100644
--- a/README.md
+++ b/README.md
@@ -32,6 +32,7 @@ let req = ChatCompletionRequest::new(
         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 6ef5035..7a31241 100644
--- a/examples/chat_completion.rs
+++ b/examples/chat_completion.rs
@@ -14,6 +14,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
             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 d2ce8cb..ddf1d3d 100644
--- a/examples/function_call.rs
+++ b/examples/function_call.rs
@@ -35,6 +35,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
             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 a6bf064..38463a5 100644
--- a/examples/function_call_role.rs
+++ b/examples/function_call_role.rs
@@ -35,6 +35,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
             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 {
@@ -89,6 +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,
@@ -97,6 +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 056feef..57397ae 100644
--- a/examples/vision.rs
+++ b/examples/vision.rs
@@ -29,6 +29,7 @@ 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 1536f9d..28284be 100644
--- a/src/v1/chat_completion.rs
+++ b/src/v1/chat_completion.rs
@@ -101,6 +101,7 @@ pub enum MessageRole {
     system,
     assistant,
     function,
+    tool,
 }
 
 #[derive(Debug, Deserialize, Clone, PartialEq, Eq)]
@@ -158,6 +159,8 @@ pub struct ChatCompletionMessage {
     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)]