[Platform] Keep forward slashes unescaped in tool call arguments

src/platform/src/Bridge/OpenResponses/Contract/ToolCallNormalizer.php

@@ -31,7 +31,7 @@ final class ToolCallNormalizer extends ModelContractNormalizer
     public function normalize(mixed $data, ?string $format = null, array $context = []): array
     {
         return [
-            'arguments' => json_encode($data->getArguments() ?: new \stdClass()),
+            'arguments' => json_encode($data->getArguments() ?: new \stdClass(), \JSON_UNESCAPED_SLASHES),
             'call_id' => $data->getId(),
             'name' => $data->getName(),
             'type' => 'function_call',

src/platform/src/Contract/Normalizer/Result/ToolCallNormalizer.php

@@ -50,7 +50,7 @@ public function normalize(mixed $data, ?string $format = null, array $context =
             'type' => 'function',
             'function' => [
                 'name' => $data->getName(),
-                'arguments' => json_encode($data->getArguments() ?: new \stdClass()),
+                'arguments' => json_encode($data->getArguments() ?: new \stdClass(), \JSON_UNESCAPED_SLASHES),
             ],
         ];
     }

src/platform/tests/Bridge/OpenResponses/Contract/ToolCallNormalizerTest.php

@@ -0,0 +1,57 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\AI\Platform\Tests\Bridge\OpenResponses\Contract;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\AI\Platform\Bridge\OpenResponses\Contract\ToolCallNormalizer;
+use Symfony\AI\Platform\Bridge\OpenResponses\ResponsesModel;
+use Symfony\AI\Platform\Contract;
+use Symfony\AI\Platform\Result\ToolCall;
+
+final class ToolCallNormalizerTest extends TestCase
+{
+    private ToolCallNormalizer $normalizer;
+
+    protected function setUp(): void
+    {
+        $this->normalizer = new ToolCallNormalizer();
+    }
+
+    public function testSupportsNormalization()
+    {
+        $context = [Contract::CONTEXT_MODEL => new ResponsesModel('gpt-4o')];
+
+        $this->assertTrue($this->normalizer->supportsNormalization(new ToolCall('id', 'function'), null, $context));
+        $this->assertFalse($this->normalizer->supportsNormalization(new \stdClass(), null, $context));
+    }
+
+    public function testNormalize()
+    {
+        $toolCall = new ToolCall('call_123', 'get_weather', ['location' => 'Paris']);
+
+        $this->assertSame([
+            'arguments' => '{"location":"Paris"}',
+            'call_id' => 'call_123',
+            'name' => 'get_weather',
+            'type' => 'function_call',
+        ], $this->normalizer->normalize($toolCall));
+    }
+
+    public function testNormalizeKeepsForwardSlashesUnescaped()
+    {
+        $toolCall = new ToolCall('call_123', 'query_assets', ['path' => '/de/shop']);
+
+        $normalized = $this->normalizer->normalize($toolCall);
+
+        $this->assertSame('{"path":"/de/shop"}', $normalized['arguments']);
+    }
+}

src/platform/tests/Contract/Normalizer/Result/ToolCallNormalizerTest.php

@@ -0,0 +1,67 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\AI\Platform\Tests\Contract\Normalizer\Result;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\AI\Platform\Contract\Normalizer\Result\ToolCallNormalizer;
+use Symfony\AI\Platform\Result\ToolCall;
+
+final class ToolCallNormalizerTest extends TestCase
+{
+    private ToolCallNormalizer $normalizer;
+
+    protected function setUp(): void
+    {
+        $this->normalizer = new ToolCallNormalizer();
+    }
+
+    public function testSupportsNormalization()
+    {
+        $this->assertTrue($this->normalizer->supportsNormalization(new ToolCall('id', 'function')));
+        $this->assertFalse($this->normalizer->supportsNormalization(new \stdClass()));
+    }
+
+    public function testGetSupportedTypes()
+    {
+        $this->assertSame([ToolCall::class => true], $this->normalizer->getSupportedTypes(null));
+    }
+
+    public function testNormalize()
+    {
+        $toolCall = new ToolCall('tool_call_123', 'get_weather', ['location' => 'Paris']);
+
+        $this->assertSame([
+            'id' => 'tool_call_123',
+            'type' => 'function',
+            'function' => [
+                'name' => 'get_weather',
+                'arguments' => '{"location":"Paris"}',
+            ],
+        ], $this->normalizer->normalize($toolCall));
+    }
+
+    public function testNormalizeKeepsForwardSlashesUnescaped()
+    {
+        $toolCall = new ToolCall('tool_call_123', 'query_assets', ['path' => '/de/shop']);
+
+        $normalized = $this->normalizer->normalize($toolCall);
+
+        $this->assertSame('{"path":"/de/shop"}', $normalized['function']['arguments']);
+    }
+
+    public function testNormalizeWithoutArguments()
+    {
+        $normalized = $this->normalizer->normalize(new ToolCall('tool_call_123', 'now'));
+
+        $this->assertSame('{}', $normalized['function']['arguments']);
+    }
+}