[Platform] Allow fetching available models per platform

[ohader]

Description

In scenarios where one needs to configure multiple platforms and specific models for a particular task within a user interface (such as CMS integration of symfony/ai) it would be beneficial to have a feature that allows to retrieve the actual available models for a given platform.

Example Code

<?php
use Symfony\AI\Platform\Bridge\Ollama\PlatformFactory;
use Symfony\AI\Platform\Capability;

require_once dirname(__DIR__).'/bootstrap.php';

$platform = PlatformFactory::create(env('OLLAMA_HOST_URL'), http_client());
$modelDefinitions = $platform->fetchModelDefinitions();

echo "Available models:\n";
foreach ($modelDefinitions as $modelDefinition) {
    $modelCapabilities = array_map(
        static fn(Capability $capability): string => $capability->value,
        $modelDefinition->getCapabilities()
    );
    echo sprintf(
        " + %s (%s)\n",
        $modelDefinition->getName(),
        implode(', ', $modelCapabilities)
    );
}

Example Output

Available models:
 + llama3.2:latest (input-messages, output-text, output-structured, tool-calling)
 + gemma3:latest (input-messages, output-text, output-structured, input-image)
 + gpt-oss:latest (input-messages, output-text, output-structured, tool-calling)
 + llama3.1:latest (input-messages, output-text, output-structured, tool-calling)
 + qwen2.5-coder:14b (input-messages, output-text, output-structured, tool-calling)
 + qwen3:latest (input-messages, output-text, output-structured, tool-calling)

[OskarStark]

Somehow related: #401 (comment)

[OskarStark]

I don’t think this should fall under the Platform’s internal responsibility. In my view, the Platform should define the capabilities, not the model. Here’s why: regardless of what a model can or cannot do, we still need a client that knows how to handle tool calls within the Platform. If a user selects a model that doesn’t support tool calling at the API level, the API should return an appropriate error (ideally).

Tracking which model supports which capabilities is more of a user-side responsibility. To me, that’s a business/domain concern rather than a technical one.

[chr-hertel]

As long as we don't provide a capability-based model-routing or sth, I agree with Oskar. But I think it would be great to have a method like getModels() - If we can pull that from the API itself or fetch it as static artifact into the lib

[OskarStark]

+1 for a static artifact aka ModelCatalog

[ohader]

The recently introduced ModelCatalog concept was really helpful here in order to provide custom behavior and models.

<?php
declare(strict_types=1);

namespace TYPO3\AI\Core\AI\Bridge\Ollama;
use Symfony\AI\Platform\Bridge\Ollama\Ollama;
use Symfony\AI\Platform\ModelCatalog\AbstractModelCatalog;

final class ModelCatalog extends AbstractModelCatalog
{
    public function __construct(private readonly PlatformPool $platformPool)
    {
        $this->models = $this->resolveActualModels();
    }
    private function resolveActualModels(): array { ... }
}

Thus, I'm closing this issue in favor of not bloating up the lib.