diff --git a/src/Responses/Chat/CreateResponseToolCall.php b/src/Responses/Chat/CreateResponseToolCall.php
index 17560b2ef..de61a4540 100644
--- a/src/Responses/Chat/CreateResponseToolCall.php
+++ b/src/Responses/Chat/CreateResponseToolCall.php
@@ -6,14 +6,18 @@
 
 final class CreateResponseToolCall
 {
+    /**
+     * @param  array<string, array<string,string>>|null  $extraContent
+     */
     private function __construct(
         public readonly string $id,
         public readonly string $type,
         public readonly CreateResponseToolCallFunction $function,
+        public readonly ?array $extraContent = null,
     ) {}
 
     /**
-     * @param  array{id: string, type?: string, function: array{name: string, arguments: string}}  $attributes
+     * @param  array{id: string, type?: string, function: array{name: string, arguments: string}, extra_content?: array<string, array<string,string>>|null}  $attributes
      */
     public static function from(array $attributes): self
     {
@@ -21,18 +25,20 @@ public static function from(array $attributes): self
             $attributes['id'],
             $attributes['type'] ?? 'function',
             CreateResponseToolCallFunction::from($attributes['function']),
+            $attributes['extra_content'] ?? null,
         );
     }
 
     /**
-     * @return array{id: string, type: string, function: array{name: string, arguments: string}}
+     * @return array{id: string, type: string, function: array{name: string, arguments: string}, extra_content?: array<string, array<string,string>>}
      */
     public function toArray(): array
     {
-        return [
+        return array_filter([
             'id' => $this->id,
             'type' => $this->type,
             'function' => $this->function->toArray(),
-        ];
+            'extra_content' => $this->extraContent,
+        ], fn (mixed $value): bool => ! is_null($value));
     }
 }
diff --git a/src/Responses/Chat/CreateStreamedResponseToolCall.php b/src/Responses/Chat/CreateStreamedResponseToolCall.php
index 9173c653b..6cf6e4270 100644
--- a/src/Responses/Chat/CreateStreamedResponseToolCall.php
+++ b/src/Responses/Chat/CreateStreamedResponseToolCall.php
@@ -6,15 +6,19 @@
 
 final class CreateStreamedResponseToolCall
 {
+    /**
+     * @param  array<string, array<string,string>>|null  $extraContent
+     */
     private function __construct(
         public readonly ?int $index,
         public readonly ?string $id,
         public readonly ?string $type,
         public readonly CreateStreamedResponseToolCallFunction $function,
+        public readonly ?array $extraContent,
     ) {}
 
     /**
-     * @param  array{index?: int, id?: string, type?: string, function: array{name?: string, arguments: string}}  $attributes
+     * @param  array{index?: int, id?: string, type?: string, function: array{name?: string, arguments: string}, extra_content?: array<string, array<string,string>>|null}  $attributes
      */
     public static function from(array $attributes): self
     {
@@ -23,11 +27,12 @@ public static function from(array $attributes): self
             $attributes['id'] ?? null,
             $attributes['type'] ?? null,
             CreateStreamedResponseToolCallFunction::from($attributes['function']),
+            $attributes['extra_content'] ?? null,
         );
     }
 
     /**
-     * @return array{index?: int, id?: string, type?: string, function?: array{name?: string, arguments: string}}
+     * @return array{index?: int, id?: string, type?: string, function?: array{name?: string, arguments: string}, extra_content?: array<string, array<string,string>>}
      */
     public function toArray(): array
     {
@@ -36,6 +41,7 @@ public function toArray(): array
             'id' => $this->id,
             'type' => $this->type,
             'function' => $this->function->toArray(),
+            'extra_content' => $this->extraContent,
         ], fn (mixed $value): bool => ! is_null($value));
     }
 }
diff --git a/tests/Fixtures/Chat.php b/tests/Fixtures/Chat.php
index f1cc56b9b..85c9ddf38 100644
--- a/tests/Fixtures/Chat.php
+++ b/tests/Fixtures/Chat.php
@@ -492,6 +492,50 @@ function chatCompletionWithToolCalls(): array
     ];
 }
 
+/**
+ * @return array<string, mixed>
+ */
+function chatCompletionWithToolCallsAndExtraContent(): array
+{
+    return [
+        'id' => 'chatcmpl-123',
+        'object' => 'chat.completion',
+        'created' => 1699333252,
+        'model' => 'gpt-3.5-turbo-0613',
+        'choices' => [
+            [
+                'index' => 0,
+                'message' => [
+                    'role' => 'assistant',
+                    'content' => null,
+                    'tool_calls' => [
+                        [
+                            'id' => 'call_trlgKnhMpYSC7CFXKw3CceUZ',
+                            'type' => 'function',
+                            'function' => [
+                                'name' => 'get_current_weather',
+                                'arguments' => "{\n  \"location\": \"Boston, MA\"\n}",
+                            ],
+                            'extra_content' => [
+                                'google' => [
+                                    'thought_signature' => 'trlgKnhMpYSC7CFXKw3CceUZ',
+                                ],
+                            ],
+                        ],
+                    ],
+                ],
+                'logprobs' => null,
+                'finish_reason' => 'tool_calls',
+            ],
+        ],
+        'usage' => [
+            'prompt_tokens' => 71,
+            'completion_tokens' => 17,
+            'total_tokens' => 88,
+        ],
+    ];
+}
+
 /**
  * @return array<string, mixed>
  */
diff --git a/tests/Responses/Chat/CreateResponseMessage.php b/tests/Responses/Chat/CreateResponseMessage.php
index 39c480f74..ba61451ce 100644
--- a/tests/Responses/Chat/CreateResponseMessage.php
+++ b/tests/Responses/Chat/CreateResponseMessage.php
@@ -33,7 +33,26 @@
         ->content->toBeNull()
         ->toolCalls->toBeArray()
         ->toolCalls->toHaveCount(1)
-        ->toolCalls->each->toBeInstanceOf(CreateResponseToolCall::class);
+        ->toolCalls->each->toBeInstanceOf(CreateResponseToolCall::class)
+        ->and($result->toolCalls[0])
+        ->extraContent->toBeNull();
+});
+
+test('from tool calls response with extra content', function () {
+    $result = CreateResponseMessage::from(chatCompletionWithToolCallsAndExtraContent()['choices'][0]['message']);
+
+    expect($result)
+        ->role->toBe('assistant')
+        ->content->toBeNull()
+        ->toolCalls->toBeArray()
+        ->toolCalls->toHaveCount(1)
+        ->toolCalls->each->toBeInstanceOf(CreateResponseToolCall::class)
+        ->and($result->toolCalls[0])
+        ->extraContent->toBeArray()
+        ->extraContent->toHaveCount(1)
+        ->extraContent->toHaveKey('google')
+        ->extraContent->google->toHaveKey('thought_signature')
+        ->extraContent->google->thought_signature->toBe('trlgKnhMpYSC7CFXKw3CceUZ');
 });
 
 test('from annotations response', function () {
@@ -94,6 +113,13 @@
         ->toBe(chatCompletionWithToolCalls()['choices'][0]['message']);
 });
 
+test('to array from tool calls response with extra content', function () {
+    $result = CreateResponseMessage::from(chatCompletionWithToolCallsAndExtraContent()['choices'][0]['message']);
+
+    expect($result->toArray())
+        ->toBe(chatCompletionWithToolCallsAndExtraContent()['choices'][0]['message']);
+});
+
 test('to array from annotations response', function () {
     $result = CreateResponseMessage::from(chatCompletionWithAnnotations()['choices'][0]['message']);