feat: tool artifacts

[sixlive]

Description

Adds support for tools to produce binary artifacts (images, audio, files) alongside text results. Artifacts flow through the streaming event system and are available to applications without going to the LLM's context window.

Key changes:

• New Artifact and ToolOutput value objects for returning binary data from tools
• New ArtifactEvent stream event emitted after tool execution
• All 9 provider stream handlers updated to yield artifact events
• DataProtocolAdapter sends artifacts as type: 'artifact' messages
• BroadcastAdapter emits .artifact WebSocket events
• Backward compatible: tools returning strings continue to work unchanged

Usage

$tool = Tool::as('generate_image')
    ->for('Generates an image')
    ->withStringParameter('prompt', 'Image description')
    ->using(function (string $prompt): ToolOutput {
        $imageData = $this->imageService->generate($prompt);

        return new ToolOutput(
            result: json_encode(['status' => 'success']),
            artifacts: [
                Artifact::fromRawContent(
                    content: $imageData,
                    mimeType: 'image/png',
                    metadata: ['width' => 1024, 'height' => 1024],
                ),
            ],
        );
    });

[kinsta]

Preview deployments for prism ⚡️

Status	Branch preview	Commit preview
✅ Ready	Visit preview	Visit preview

Commit: e4fd3b775acde9f822304d5e0559a01eb776a665

Deployment ID: 4c314ec6-5f33-4ab7-a6e0-661e1b56f2ae

Static site name: prism-97nz9