diff --git a/README.md b/README.md
index 32138174..0a353e7c 100644
--- a/README.md
+++ b/README.md
@@ -53,7 +53,7 @@ Provided Tools
 * [x] SerpApi
 * [x] Clock
 * [x] Wikipedia
-* [ ] Weather
+* [x] Weather
 
 Usage Examples
 --------------
diff --git a/examples/toolchain-weather.php b/examples/toolchain-weather.php
new file mode 100755
index 00000000..1be8649b
--- /dev/null
+++ b/examples/toolchain-weather.php
@@ -0,0 +1,28 @@
+<?php
+
+use PhpLlm\LlmChain\Chain;
+use PhpLlm\LlmChain\Message\Message;
+use PhpLlm\LlmChain\Message\MessageBag;
+use PhpLlm\LlmChain\OpenAI\Model\Gpt;
+use PhpLlm\LlmChain\OpenAI\Model\Gpt\Version;
+use PhpLlm\LlmChain\OpenAI\Runtime\OpenAI;
+use PhpLlm\LlmChain\ToolBox\ParameterAnalyzer;
+use PhpLlm\LlmChain\ToolBox\Registry;
+use PhpLlm\LlmChain\ToolBox\Tool\OpenMeteo;
+use PhpLlm\LlmChain\ToolBox\ToolAnalyzer;
+use Symfony\Component\HttpClient\HttpClient;
+
+require_once dirname(__DIR__).'/vendor/autoload.php';
+
+$httpClient = HttpClient::create();
+$runtime = new OpenAI($httpClient, getenv('OPENAI_API_KEY'));
+$llm = new Gpt($runtime, Version::GPT_4o_MINI);
+
+$wikipedia = new OpenMeteo($httpClient);
+$registry = new Registry(new ToolAnalyzer(new ParameterAnalyzer()), [$wikipedia]);
+$chain = new Chain($llm, $registry);
+
+$messages = new MessageBag(Message::ofUser('How is the weather currently in Berlin?'));
+$response = $chain->call($messages);
+
+echo $response.PHP_EOL;
diff --git a/src/ToolBox/Metadata.php b/src/ToolBox/Metadata.php
index d55ef8db..d6c94d2e 100644
--- a/src/ToolBox/Metadata.php
+++ b/src/ToolBox/Metadata.php
@@ -7,7 +7,7 @@
 /**
  * @phpstan-import-type ParameterDefinition from ParameterAnalyzer
  */
-final class Metadata
+final class Metadata implements \JsonSerializable
 {
     /**
      * @param ParameterDefinition|null $parameters
@@ -20,4 +20,31 @@ public function __construct(
         public readonly ?array $parameters,
     ) {
     }
+
+    /**
+     * @return array{
+     *     type: 'function',
+     *     function: array{
+     *         name: string,
+     *         description: string,
+     *         parameters?: ParameterDefinition
+     *     }
+     * }
+     */
+    public function jsonSerialize(): array
+    {
+        $function = [
+            'name' => $this->name,
+            'description' => $this->description,
+        ];
+
+        if (isset($this->parameters)) {
+            $function['parameters'] = $this->parameters;
+        }
+
+        return [
+            'type' => 'function',
+            'function' => $function,
+        ];
+    }
 }
diff --git a/src/ToolBox/ParameterAnalyzer.php b/src/ToolBox/ParameterAnalyzer.php
index 5587541d..1f7849a5 100644
--- a/src/ToolBox/ParameterAnalyzer.php
+++ b/src/ToolBox/ParameterAnalyzer.php
@@ -40,6 +40,10 @@ public function getDefinition(string $className, string $methodName): ?array
                 $paramType = 'integer';
             }
 
+            if ('float' === $paramType) {
+                $paramType = 'number';
+            }
+
             if (!$parameter->isOptional()) {
                 $result['required'][] = $paramName;
             }
diff --git a/src/ToolBox/Registry.php b/src/ToolBox/Registry.php
index 809c619b..da67c8a8 100644
--- a/src/ToolBox/Registry.php
+++ b/src/ToolBox/Registry.php
@@ -6,9 +6,6 @@
 
 use PhpLlm\LlmChain\Response\ToolCall;
 
-/**
- * @phpstan-import-type ToolDefinition from RegistryInterface
- */
 final class Registry implements RegistryInterface
 {
     /**
@@ -17,7 +14,7 @@ final class Registry implements RegistryInterface
     private readonly array $tools;
 
     /**
-     * @var list<ToolDefinition>
+     * @var Metadata[]
      */
     private array $map;
 
@@ -40,19 +37,7 @@ public function getMap(): array
         $map = [];
         foreach ($this->tools as $tool) {
             foreach ($this->toolAnalyzer->getMetadata($tool::class) as $metadata) {
-                $function = [
-                    'name' => $metadata->name,
-                    'description' => $metadata->description,
-                ];
-
-                if (isset($metadata->parameters)) {
-                    $function['parameters'] = $metadata->parameters;
-                }
-
-                $map[] = [
-                    'type' => 'function',
-                    'function' => $function,
-                ];
+                $map[] = $metadata;
             }
         }
 
diff --git a/src/ToolBox/RegistryInterface.php b/src/ToolBox/RegistryInterface.php
index b0646fca..57c1a29a 100644
--- a/src/ToolBox/RegistryInterface.php
+++ b/src/ToolBox/RegistryInterface.php
@@ -6,22 +6,10 @@
 
 use PhpLlm\LlmChain\Response\ToolCall;
 
-/**
- * @phpstan-import-type ParameterDefinition from ParameterAnalyzer
- *
- * @phpstan-type ToolDefinition = array{
- *      type: 'function',
- *      function: array{
- *          name: string,
- *          description: string,
- *          parameters?: ParameterDefinition
- *      }
- *  }
- */
 interface RegistryInterface
 {
     /**
-     * @return list<ToolDefinition>
+     * @return Metadata[]
      */
     public function getMap(): array;
 
diff --git a/src/ToolBox/Tool/OpenMeteo.php b/src/ToolBox/Tool/OpenMeteo.php
new file mode 100644
index 00000000..9823de5c
--- /dev/null
+++ b/src/ToolBox/Tool/OpenMeteo.php
@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpLlm\LlmChain\ToolBox\Tool;
+
+use PhpLlm\LlmChain\ToolBox\AsTool;
+use Symfony\Contracts\HttpClient\HttpClientInterface;
+
+#[AsTool(name: 'weather', description: 'get the current weather for a location')]
+final readonly class OpenMeteo
+{
+    public function __construct(
+        private HttpClientInterface $httpClient,
+    ) {
+    }
+
+    /**
+     * @param float $latitude  the latitude of the location
+     * @param float $longitude the longitude of the location
+     */
+    public function __invoke(float $latitude, float $longitude): string
+    {
+        $response = $this->httpClient->request('GET', 'https://api.open-meteo.com/v1/forecast', [
+            'query' => [
+                'latitude' => $latitude,
+                'longitude' => $longitude,
+                'current' => 'temperature_2m,wind_speed_10m',
+            ],
+        ]);
+
+        return $response->getContent();
+    }
+}
diff --git a/tests/ToolBox/RegistryTest.php b/tests/ToolBox/RegistryTest.php
index 7fdaf218..42436573 100644
--- a/tests/ToolBox/RegistryTest.php
+++ b/tests/ToolBox/RegistryTest.php
@@ -89,7 +89,7 @@ public function testFunctionsMap(): void
             ],
         ];
 
-        self::assertSame($expected, $actual);
+        self::assertSame(json_encode($expected), json_encode($actual));
     }
 
     public function testExecute(): void