diff --git a/src/v1/chat_completion.rs b/src/v1/chat_completion.rs
index f66c1e6..8ae275a 100644
--- a/src/v1/chat_completion.rs
+++ b/src/v1/chat_completion.rs
@@ -13,14 +13,29 @@ pub enum FunctionCallType {
     Function { name: String },
 }
 
+#[derive(Debug, Serialize, Clone)]
+pub enum ToolChoiceType {
+    None,
+    Auto,
+    ToolChoice { tool: Tool },
+}
+
 #[derive(Debug, Serialize, Clone)]
 pub struct ChatCompletionRequest {
     pub model: String,
     pub messages: Vec<ChatCompletionMessage>,
     #[serde(skip_serializing_if = "Option::is_none")]
+    #[deprecated(
+        since = "2.1.5",
+        note = "This field is deprecated. Use `tools` instead."
+    )]
     pub functions: Option<Vec<Function>>,
     #[serde(skip_serializing_if = "Option::is_none")]
     #[serde(serialize_with = "serialize_function_call")]
+    #[deprecated(
+        since = "2.1.5",
+        note = "This field is deprecated. Use `tool_choice` instead."
+    )]
     pub function_call: Option<FunctionCallType>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub temperature: Option<f64>,
@@ -46,6 +61,11 @@ pub struct ChatCompletionRequest {
     pub user: Option<String>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub seed: Option<i64>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub tools: Option<Vec<Tool>>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    #[serde(serialize_with = "serialize_tool_choice")]
+    pub tool_choice: Option<ToolChoiceType>,
 }
 
 impl ChatCompletionRequest {
@@ -67,6 +87,8 @@ impl ChatCompletionRequest {
             logit_bias: None,
             user: None,
             seed: None,
+            tools: None,
+            tool_choice: None,
         }
     }
 }
@@ -86,7 +108,9 @@ impl_builder_methods!(
     frequency_penalty: f64,
     logit_bias: HashMap<String, i32>,
     user: String,
-    seed: i64
+    seed: i64,
+    tools: Vec<Tool>,
+    tool_choice: ToolChoiceType
 );
 
 #[derive(Debug, Serialize, Deserialize, Clone)]
@@ -225,3 +249,30 @@ where
         None => serializer.serialize_none(),
     }
 }
+
+fn serialize_tool_choice<S>(
+    value: &Option<ToolChoiceType>,
+    serializer: S,
+) -> Result<S::Ok, S::Error>
+where
+    S: Serializer,
+{
+    match value {
+        Some(ToolChoiceType::None) => serializer.serialize_str("none"),
+        Some(ToolChoiceType::Auto) => serializer.serialize_str("auto"),
+        Some(ToolChoiceType::ToolChoice { tool }) => {
+            let mut map = serializer.serialize_map(Some(2))?;
+            map.serialize_entry("type", &tool.tool_type)?;
+            map.serialize_entry("function", &tool.function)?;
+            map.end()
+        }
+        None => serializer.serialize_none(),
+    }
+}
+
+#[derive(Debug, Serialize, Deserialize, Clone)]
+pub struct Tool {
+    #[serde(rename = "type")]
+    tool_type: String,
+    function: Function,
+}