diff --git a/src/Responses/Chat/CreateResponse.php b/src/Responses/Chat/CreateResponse.php
index 3d424e8b..254915d1 100644
--- a/src/Responses/Chat/CreateResponse.php
+++ b/src/Responses/Chat/CreateResponse.php
@@ -41,7 +41,7 @@ private function __construct(
     /**
      * Acts as static factory, and returns a new Response instance.
      *
-     * @param  array{id: string, object: string, created: int, model: string, system_fingerprint?: string, choices: array<int, array{index: int, message: array{role: string, content: ?string, function_call: ?array{name: string, arguments: string}, tool_calls: ?array<int, array{id: string, type: string, function: array{name: string, arguments: string}}>}, finish_reason: string|null}>, usage: array{prompt_tokens: int, completion_tokens: int|null, total_tokens: int, prompt_tokens_details?:array{cached_tokens:int}, completion_tokens_details?:array{audio_tokens?:int, reasoning_tokens:int, accepted_prediction_tokens:int, rejected_prediction_tokens:int}}}  $attributes
+     * @param  array{id: string, object: string, created: int, model: string, system_fingerprint?: string, choices: array<int, array{index: int, message: array{role: string, content: ?string, function_call: ?array{name: string, arguments: string}, tool_calls: ?array<int, array{id: string, type: string, function: array{name: string, arguments: string}}>}, finish_reason: string|null}>, usage: array{prompt_tokens: int, completion_tokens: int|null, total_tokens: int, prompt_tokens_details?:array{cached_tokens:int}, completion_tokens_details?:array{audio_tokens?:int, reasoning_tokens?:int, accepted_prediction_tokens?:int, rejected_prediction_tokens?:int}}}  $attributes
      */
     public static function from(array $attributes, MetaInformation $meta): self
     {
diff --git a/src/Responses/Chat/CreateResponseUsage.php b/src/Responses/Chat/CreateResponseUsage.php
index 07ba4191..d8899271 100644
--- a/src/Responses/Chat/CreateResponseUsage.php
+++ b/src/Responses/Chat/CreateResponseUsage.php
@@ -15,7 +15,7 @@ private function __construct(
     ) {}
 
     /**
-     * @param  array{prompt_tokens: int, completion_tokens: int|null, total_tokens: int, prompt_tokens_details?:array{cached_tokens:int}, completion_tokens_details?:array{audio_tokens?:int, reasoning_tokens:int, accepted_prediction_tokens:int, rejected_prediction_tokens:int}}  $attributes
+     * @param  array{prompt_tokens: int, completion_tokens: int|null, total_tokens: int, prompt_tokens_details?:array{cached_tokens:int}, completion_tokens_details?:array{audio_tokens?:int, reasoning_tokens?:int, accepted_prediction_tokens?:int, rejected_prediction_tokens?:int}}  $attributes
      */
     public static function from(array $attributes): self
     {
diff --git a/src/Responses/Chat/CreateResponseUsageCompletionTokensDetails.php b/src/Responses/Chat/CreateResponseUsageCompletionTokensDetails.php
index 989ee27b..041a4477 100644
--- a/src/Responses/Chat/CreateResponseUsageCompletionTokensDetails.php
+++ b/src/Responses/Chat/CreateResponseUsageCompletionTokensDetails.php
@@ -8,39 +8,47 @@ final class CreateResponseUsageCompletionTokensDetails
 {
     private function __construct(
         public readonly ?int $audioTokens,
-        public readonly int $reasoningTokens,
-        public readonly int $acceptedPredictionTokens,
-        public readonly int $rejectedPredictionTokens
+        public readonly ?int $reasoningTokens,
+        public readonly ?int $acceptedPredictionTokens,
+        public readonly ?int $rejectedPredictionTokens
     ) {}
 
     /**
-     * @param  array{audio_tokens?:int, reasoning_tokens:int, accepted_prediction_tokens:int, rejected_prediction_tokens:int}  $attributes
+     * @param  array{audio_tokens?:int, reasoning_tokens?:int, accepted_prediction_tokens?:int, rejected_prediction_tokens?:int}  $attributes
      */
     public static function from(array $attributes): self
     {
         return new self(
             $attributes['audio_tokens'] ?? null,
-            $attributes['reasoning_tokens'],
-            $attributes['accepted_prediction_tokens'],
-            $attributes['rejected_prediction_tokens'],
+            $attributes['reasoning_tokens'] ?? null,
+            $attributes['accepted_prediction_tokens'] ?? null,
+            $attributes['rejected_prediction_tokens'] ?? null,
         );
     }
 
     /**
-     * @return array{audio_tokens?:int, reasoning_tokens:int, accepted_prediction_tokens:int, rejected_prediction_tokens:int}
+     * @return array{audio_tokens?:int, reasoning_tokens?:int, accepted_prediction_tokens?:int, rejected_prediction_tokens?:int}
      */
     public function toArray(): array
     {
-        $result = [
-            'reasoning_tokens' => $this->reasoningTokens,
-            'accepted_prediction_tokens' => $this->acceptedPredictionTokens,
-            'rejected_prediction_tokens' => $this->rejectedPredictionTokens,
-        ];
+        $result = [];
 
-        if (! is_null($this->audioTokens)) {
+        if ($this->audioTokens !== null) {
             $result['audio_tokens'] = $this->audioTokens;
         }
 
+        if ($this->reasoningTokens !== null) {
+            $result['reasoning_tokens'] = $this->reasoningTokens;
+        }
+
+        if ($this->acceptedPredictionTokens !== null) {
+            $result['accepted_prediction_tokens'] = $this->acceptedPredictionTokens;
+        }
+
+        if ($this->rejectedPredictionTokens !== null) {
+            $result['rejected_prediction_tokens'] = $this->rejectedPredictionTokens;
+        }
+
         return $result;
     }
 }