feature #936 [Platform][Anthropic] Add support for structured output on Claude API (chr-hertel)

This PR was merged into the main branch.

Discussion
----------

[Platform][Anthropic] Add support for structured output on Claude API

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| Docs?         | no
| Issues        |
| License       | MIT

Adding support for recently released beta feature of structured output on Anthropic API, see https://claude.com/blog/structured-outputs-on-the-claude-developer-platform

Commits
-------

e926440 Add support for structured output on Claude API

Author: chr-hertel

examples/anthropic/structured-output-clock.php

@@ -0,0 +1,53 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+use Symfony\AI\Agent\Agent;
+use Symfony\AI\Agent\Toolbox\AgentProcessor;
+use Symfony\AI\Agent\Toolbox\Tool\Clock;
+use Symfony\AI\Agent\Toolbox\Toolbox;
+use Symfony\AI\Platform\Bridge\Anthropic\PlatformFactory;
+use Symfony\AI\Platform\Message\Message;
+use Symfony\AI\Platform\Message\MessageBag;
+use Symfony\AI\Platform\StructuredOutput\PlatformSubscriber;
+use Symfony\Component\Clock\Clock as SymfonyClock;
+use Symfony\Component\EventDispatcher\EventDispatcher;
+
+require_once dirname(__DIR__).'/bootstrap.php';
+
+$dispatcher = new EventDispatcher();
+$dispatcher->addSubscriber(new PlatformSubscriber());
+
+$platform = PlatformFactory::create(env('ANTHROPIC_API_KEY'), http_client(), eventDispatcher: $dispatcher);
+
+$clock = new Clock(new SymfonyClock());
+$toolbox = new Toolbox([$clock], logger: logger());
+$toolProcessor = new AgentProcessor($toolbox);
+$agent = new Agent($platform, 'claude-sonnet-4-5-20250929', [$toolProcessor], [$toolProcessor]);
+
+$messages = new MessageBag(Message::ofUser('What date and time is it?'));
+$result = $agent->call($messages, ['response_format' => [
+    'type' => 'json_schema',
+    'json_schema' => [
+        'name' => 'clock',
+        'strict' => true,
+        'schema' => [
+            'type' => 'object',
+            'properties' => [
+                'date' => ['type' => 'string', 'description' => 'The current date in the format YYYY-MM-DD.'],
+                'time' => ['type' => 'string', 'description' => 'The current time in the format HH:MM:SS.'],
+            ],
+            'required' => ['date', 'time'],
+            'additionalProperties' => false,
+        ],
+    ],
+]]);
+
+dump($result->getContent());

examples/anthropic/structured-output-math.php

@@ -0,0 +1,32 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+use Symfony\AI\Fixtures\StructuredOutput\MathReasoning;
+use Symfony\AI\Platform\Bridge\Anthropic\PlatformFactory;
+use Symfony\AI\Platform\Message\Message;
+use Symfony\AI\Platform\Message\MessageBag;
+use Symfony\AI\Platform\StructuredOutput\PlatformSubscriber;
+use Symfony\Component\EventDispatcher\EventDispatcher;
+
+require_once dirname(__DIR__).'/bootstrap.php';
+
+$dispatcher = new EventDispatcher();
+$dispatcher->addSubscriber(new PlatformSubscriber());
+
+$platform = PlatformFactory::create(env('ANTHROPIC_API_KEY'), http_client(), eventDispatcher: $dispatcher);
+$messages = new MessageBag(
+    Message::forSystem('You are a helpful math tutor. Guide the user through the solution step by step.'),
+    Message::ofUser('how can I solve 8x + 7 = -23'),
+);
+
+$result = $platform->invoke('claude-sonnet-4-5-20250929', $messages, ['response_format' => MathReasoning::class]);
+
+dump($result->asObject());

src/platform/src/Bridge/Anthropic/ModelClient.php

@@ -47,6 +47,15 @@ public function request(Model $model, array|string $payload, array $options = []
             $options['tool_choice'] = ['type' => 'auto'];
         }
 
+        if (isset($options['response_format'])) {
+            $options['beta_features'][] = 'structured-outputs-2025-11-13';
+            $options['output_format'] = [
+                'type' => 'json_schema',
+                'schema' => $options['response_format']['json_schema']['schema'] ?? [],
+            ];
+            unset($options['response_format']);
+        }
+
         if (isset($options['beta_features']) && \is_array($options['beta_features']) && \count($options['beta_features']) > 0) {
             $headers['anthropic-beta'] = implode(',', $options['beta_features']);
             unset($options['beta_features']);