From 856dfd20ceaeba8393bc36dc52559a6ce28694a0 Mon Sep 17 00:00:00 2001
From: Leopold Jacquot <leopold.jacquot@infomaniak.com>
Date: Mon, 9 Mar 2026 09:58:37 +0100
Subject: [PATCH] fix: streaming reasoning content

---
 .../Chat/CreateStreamedResponseDelta.php      |  7 +++++--
 tests/Fixtures/Chat.php                       | 19 +++++++++++++++++++
 .../Chat/CreateStreamedResponseDelta.php      | 16 ++++++++++++++++
 3 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/src/Responses/Chat/CreateStreamedResponseDelta.php b/src/Responses/Chat/CreateStreamedResponseDelta.php
index 6439122e..817ee40a 100644
--- a/src/Responses/Chat/CreateStreamedResponseDelta.php
+++ b/src/Responses/Chat/CreateStreamedResponseDelta.php
@@ -12,12 +12,13 @@ final class CreateStreamedResponseDelta
     private function __construct(
         public readonly ?string $role,
         public readonly ?string $content,
+        public readonly ?string $reasoningContent,
         public readonly array $toolCalls,
         public readonly ?CreateStreamedResponseFunctionCall $functionCall,
     ) {}
 
     /**
-     * @param  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}}>}  $attributes
+     * @param  array{role?: string, content?: string, reasoning?: string, function_call?: array{name?: ?string, arguments?: ?string}, tool_calls?: array<int, array{id?: string, type?: string, function: array{name?: string, arguments: string}}>}  $attributes
      */
     public static function from(array $attributes): self
     {
@@ -28,19 +29,21 @@ public static function from(array $attributes): self
         return new self(
             $attributes['role'] ?? null,
             $attributes['content'] ?? null,
+            $attributes['reasoning'] ?? null,
             $toolCalls,
             isset($attributes['function_call']) ? CreateStreamedResponseFunctionCall::from($attributes['function_call']) : null,
         );
     }
 
     /**
-     * @return array{role?: string, content?: string}|array{role?: string, content: null, function_call: array{name?: string, arguments?: string}}
+     * @return array{role?: string, content?: string, reasoning?: string}|array{role?: string, content: null, function_call: array{name?: string, arguments?: string}}
      */
     public function toArray(): array
     {
         $data = array_filter([
             'role' => $this->role,
             'content' => $this->content,
+            'reasoning' => $this->reasoningContent,
         ], fn (?string $value): bool => ! is_null($value));
 
         if ($this->functionCall instanceof CreateStreamedResponseFunctionCall) {
diff --git a/tests/Fixtures/Chat.php b/tests/Fixtures/Chat.php
index 8fd93440..f1cc56b9 100644
--- a/tests/Fixtures/Chat.php
+++ b/tests/Fixtures/Chat.php
@@ -722,6 +722,25 @@ function chatCompletionStreamVisionContentChunk(): array
     ];
 }
 
+function chatCompletionStreamReasoningChunk(): array
+{
+    return [
+        'id' => 'chatcmpl-123',
+        'object' => 'chat.completion.chunk',
+        'created' => 1677652288,
+        'model' => 'deepseek-reasoner',
+        'choices' => [
+            [
+                'index' => 0,
+                'delta' => [
+                    'reasoning' => 'Hello world',
+                ],
+                'finish_reason' => null,
+            ],
+        ],
+    ];
+}
+
 /**
  * @return array<string, mixed>
  */
diff --git a/tests/Responses/Chat/CreateStreamedResponseDelta.php b/tests/Responses/Chat/CreateStreamedResponseDelta.php
index 7b8bb021..595e6c92 100644
--- a/tests/Responses/Chat/CreateStreamedResponseDelta.php
+++ b/tests/Responses/Chat/CreateStreamedResponseDelta.php
@@ -88,3 +88,19 @@
     expect($result->toArray())
         ->toBe($data);
 });
+
+test('from reasoning chunk', function () {
+    $result = CreateStreamedResponseDelta::from(chatCompletionStreamReasoningChunk()['choices'][0]['delta']);
+
+    expect($result)
+        ->role->toBeNull()
+        ->content->toBeNull()
+        ->reasoningContent->toBe('Hello world');
+});
+
+test('to array for a reasoning chunk', function () {
+    $result = CreateStreamedResponseDelta::from(chatCompletionStreamReasoningChunk()['choices'][0]['delta']);
+
+    expect($result->toArray())
+        ->toBe(chatCompletionStreamReasoningChunk()['choices'][0]['delta']);
+});