feat: add tool call event

[chr-hertel]

Closes #168

[chr-hertel]

Tests currently failing since i moved tool result conversion into the chain processor, but would that be a way to go for you @OskarStark ?

final class SpecificToolCallSubscriber implement EventSubscriberInterface
{
    public static function getSubscribedEvents()
    {
        return [
            ToolCallExecuted::class => 'handleToolCall',
        ];
    }

    public function handleToolCall(ToolCallExecuted $event): void
    {
        foreach ($event->toolCallResults as $toolCallResult) {
            if ('xyz' === $toolCallResult->toolCall->name) {
                $event->response = new StructuredResponse($toolCallResult->result);
            }
        }
    }
}

See example:

llm-chain/examples/toolbox-weather-event.php

Lines 26 to 47 in f096dba

	$platform = PlatformFactory::create($_ENV['OPENAI_API_KEY']);
	$llm = new GPT(GPT::GPT_4O_MINI);
	$openMeteo = new OpenMeteo(HttpClient::create());
	$toolBox = new ToolBox(new ToolAnalyzer(), [$openMeteo]);
	$eventDispatcher = new EventDispatcher();
	$processor = new ChainProcessor($toolBox, $eventDispatcher);
	$chain = new Chain($platform, $llm, [$processor], [$processor]);
	// Add tool call result listener to enforce chain exits direct with structured response for weather tools
	$eventDispatcher->addListener(ToolCallExecuted::class, function (ToolCallExecuted $event): void {
	foreach ($event->toolCallResults as $toolCallResult) {
	if (str_starts_with($toolCallResult->toolCall->name, 'weather_')) {
	$event->response = new StructuredResponse($toolCallResult->result);
	}
	}
	});
	$messages = new MessageBag(Message::ofUser('How is the weather currently in Berlin?'));
	$response = $chain->call($messages);
	dump($response->getContent());

[OskarStark]

Uhhhhhhh that looks nice 😍 will have a detailed look when on my Mac 💻👍🏻

Thanks for taking time

[OskarStark]

The event name is singular and then you iterate over all toolCallResults (plural), that feels weird. Shouldn't we throw an event for every ToolCall which was executed?

Otherwise rename it to ToolCallsExecuted?

Or am I missing sth.?

[chr-hertel]

you're right. should be plural

[OskarStark]

I like it 👍 Looks like I can achieve my goals with it 🕺