feat: support date time tool results (#263)

Author: chr-hertel

examples/toolbox-clock.php

@@ -4,10 +4,11 @@
 use PhpLlm\LlmChain\Bridge\OpenAI\PlatformFactory;
 use PhpLlm\LlmChain\Chain;
 use PhpLlm\LlmChain\Chain\Toolbox\ChainProcessor;
-use PhpLlm\LlmChain\Chain\Toolbox\Tool\Clock;
+use PhpLlm\LlmChain\Chain\Toolbox\MetadataFactory\MemoryFactory;
 use PhpLlm\LlmChain\Chain\Toolbox\Toolbox;
 use PhpLlm\LlmChain\Model\Message\Message;
 use PhpLlm\LlmChain\Model\Message\MessageBag;
+use Symfony\Component\Clock\Clock;
 use Symfony\Component\Dotenv\Dotenv;
 
 require_once dirname(__DIR__).'/vendor/autoload.php';
@@ -21,8 +22,9 @@
 $platform = PlatformFactory::create($_ENV['OPENAI_API_KEY']);
 $llm = new GPT(GPT::GPT_4O_MINI);
 
-$clock = new Clock();
-$toolbox = Toolbox::create($clock);
+$metadataFactory = (new MemoryFactory())
+    ->addTool(Clock::class, 'clock', 'Get the current date and time', 'now');
+$toolbox = new Toolbox($metadataFactory, [new Clock()]);
 $processor = new ChainProcessor($toolbox);
 $chain = new Chain($platform, $llm, [$processor], [$processor]);
 

src/Chain/Toolbox/ToolResultConverter.php

@@ -9,7 +9,7 @@
     /**
      * @param \JsonSerializable|\Stringable|array<int|string, mixed>|float|string|null $result
      */
-    public function convert(\JsonSerializable|\Stringable|array|float|string|null $result): ?string
+    public function convert(\JsonSerializable|\Stringable|array|float|string|\DateTimeInterface|null $result): ?string
     {
         if (null === $result) {
             return null;
@@ -23,6 +23,10 @@ public function convert(\JsonSerializable|\Stringable|array|float|string|null $r
             return (string) $result;
         }
 
+        if ($result instanceof \DateTimeInterface) {
+            return $result->format(DATE_ATOM);
+        }
+
         return $result;
     }
 }

tests/Chain/Toolbox/ToolResultConverterTest.php

@@ -34,6 +34,8 @@ public static function provideResults(): \Generator
 
         yield 'string' => ['plain string', 'plain string'];
 
+        yield 'datetime' => [new \DateTimeImmutable('2021-07-31 12:34:56'), '2021-07-31T12:34:56+00:00'];
+
         yield 'stringable' => [
             new class implements \Stringable {
                 public function __toString(): string