prism-php/prism v0.92.0 on GitHub

What's Changed

New streaming output by @sixlive in #601

⚠️ BREAKING CHANGES

1. Removed `Chunk` Class and `ChunkType` Enum

What changed:

The Prism\Prism\Text\Chunk class has been removed
The Prism\Prism\Enums\ChunkType enum has been removed
PendingRequest::asStream() now returns Generator<StreamEvent> instead of Generator<Chunk>

Before:

use Prism\Prism\Text\Chunk;
use Prism\Prism\Enums\ChunkType;

foreach ($prism->text()->asStream() as $chunk) {
    // $chunk is instance of Chunk
    echo $chunk->text;

    if ($chunk->chunkType === ChunkType::ToolCall) {
        // Handle tool calls
    }

    if ($chunk->finishReason) {
        // Stream complete
    }
}

After:

use Prism\Prism\Streaming\Events\{
    StreamStartEvent,
    TextDeltaEvent,
    TextCompleteEvent,
    ToolCallEvent,
    StreamEndEvent
};

foreach ($prism->text()->asStream() as $event) {
    // $event is instance of StreamEvent
    match ($event::class) {
        StreamStartEvent::class => /* stream started */,
        TextDeltaEvent::class => echo $event->delta,
        ToolCallEvent::class => /* handle tool call */,
        StreamEndEvent::class => /* stream complete */,
        default => /* other events */
    };
}

2. Exception Renamed

What changed:

PrismChunkDecodeException renamed to PrismStreamDecodeException

Migration:

// Before
use Prism\Prism\Exceptions\PrismChunkDecodeException;

try {
    // ...
} catch (PrismChunkDecodeException $e) {
    // ...
}

// After
use Prism\Prism\Exceptions\PrismStreamDecodeException;

try {
    // ...
} catch (PrismStreamDecodeException $e) {
    // ...
}

3. Stream Event Type Changes

The streaming output is now composed of 12 distinct event types, each with specific purposes:

Event	Purpose
`StreamStartEvent`	Emitted once at stream initialization
`TextStartEvent`	Emitted before first text delta
`TextDeltaEvent`	Contains incremental text chunks
`TextCompleteEvent`	Text generation complete
`ThinkingStartEvent`	Reasoning/thinking block started
`ThinkingEvent`	Incremental thinking content
`ThinkingCompleteEvent`	Thinking block complete
`ToolCallEvent`	Tool invocation requested
`ToolResultEvent`	Tool execution result
`CitationEvent`	Source citation (Anthropic)
`ErrorEvent`	Recoverable or fatal error
`StreamEndEvent`	Stream complete with final metadata

Migration Guide

Basic Streaming

Before (Chunk-based):

$response = '';

foreach ($prism->text()->asStream() as $chunk) {
    $response .= $chunk->text;
}

echo $response;

After (Event-based):

use Prism\Prism\Streaming\Events\TextDeltaEvent;

$response = '';

foreach ($prism->text()->asStream() as $event) {
    if ($event instanceof TextDeltaEvent) {
        $response .= $event->delta;
    }
}

echo $response;

Handling Tool Calls

Before:

foreach ($prism->text()->asStream() as $chunk) {
    if ($chunk->chunkType === ChunkType::ToolCall) {
        foreach ($chunk->toolCalls as $toolCall) {
            // Handle tool call
        }
    }
}

After:

use Prism\Prism\Streaming\Events\ToolCallEvent;

foreach ($prism->text()->asStream() as $event) {
    if ($event instanceof ToolCallEvent) {
        // Handle tool call
        $toolCall = $event->toolCall;
    }
}

Detecting Stream Completion

Before:

foreach ($prism->text()->asStream() as $chunk) {
    if ($chunk->finishReason) {
        echo "Stream finished: {$chunk->finishReason->value}";
    }
}

After:

use Prism\Prism\Streaming\Events\StreamEndEvent;

foreach ($prism->text()->asStream() as $event) {
    if ($event instanceof StreamEndEvent) {
        echo "Stream finished: {$event->finishReason->value}";
        // Access usage metadata: $event->usage
    }
}

Handling Thinking/Reasoning

Before:

foreach ($prism->text()->asStream() as $chunk) {
    if ($chunk->chunkType === ChunkType::Thinking) {
        echo "Thinking: {$chunk->text}";
    }
}

After:

use Prism\Prism\Streaming\Events\ThinkingEvent;

foreach ($prism->text()->asStream() as $event) {
    if ($event instanceof ThinkingEvent) {
        echo "Thinking: {$event->delta}";
    }
}

New Features

1. Granular Stream Events

Each phase of streaming now emits specific events, enabling fine-grained control:

use Prism\Prism\Streaming\Events\{
    StreamStartEvent,
    TextStartEvent,
    TextDeltaEvent,
    TextCompleteEvent,
    StreamEndEvent
};

foreach ($prism->text()->asStream() as $event) {
    match ($event::class) {
        StreamStartEvent::class => log('Stream started', [
            'model' => $event->model,
            'provider' => $event->provider,
        ]),
        TextStartEvent::class => log('Text generation started'),
        TextDeltaEvent::class => echo $event->delta,
        TextCompleteEvent::class => log('Text generation complete'),
        StreamEndEvent::class => log('Stream ended', [
            'finish_reason' => $event->finishReason->value,
            'usage' => $event->usage,
        ]),
    };
}

2. Streaming Adapters

Three new adapters for different streaming protocols:

Server-Sent Events (SSE)

return $prism->text()
    ->withPrompt('Tell me a story')
    ->asEventStreamResponse(); // Returns StreamedResponse with SSE format

Data Protocol (Vercel AI SDK compatible)

return $prism->text()
    ->withPrompt('Tell me a story')
    ->asDataStreamResponse(); // Returns StreamedResponse with data protocol

Laravel Broadcasting

use Illuminate\Broadcasting\Channel;

return $prism->text()
    ->withPrompt('Tell me a story')
    ->asBroadcastResponse(new Channel('prism-stream'));

3. onComplete Callback

$prism->text()
    ->withPrompt('Analyze this data')
    ->onComplete(function ($request, $messages) {
        // Save conversation to database
        Conversation::create([
            'messages' => $messages,
            'model' => $request->model,
        ]);
    })
    ->asStream();

The callback receives:

$request: The original PendingRequest instance
$messages: Collection of final Message objects

4. StreamCollector Utility

Automatically collects stream events into final messages:

use Prism\Prism\Streaming\StreamCollector;

$stream = $prism->text()->asStream();
$collector = new StreamCollector($stream, $request, $callback);

foreach ($collector->collect() as $event) {
    // Events are yielded while being collected
}

// After iteration, access collected messages
$messages = $collector->messages();

5. Testing Improvements

New fake methods for testing streaming:

use Prism\Prism\Testing\PrismFake;

PrismFake::fake([
    'mistral-large-latest' => PrismFake::streamResponse([
        'Text response content',
    ]),
]);

foreach ($prism->text()->asStream() as $event) {
    // Test against stream events
}

Internal Improvements

Unified StreamState Architecture

All 9 streaming providers now use a consistent StreamState object for managing streaming state:

Providers Refactored:

Anthropic (AnthropicStreamState extension)
OpenAI (base StreamState)
Gemini (base StreamState)
Groq (base StreamState)
Mistral (base StreamState)
Ollama (OllamaStreamState extension)
XAI (base StreamState)
DeepSeek (base StreamState)
OpenRouter (base StreamState)

Benefits:

Consistent state management across all providers
Fluent API for state mutations (withMessageId(), appendText(), etc.)
Provider extensibility via inheritance (e.g., OllamaStreamState for token accumulation)
Type-safe operations with strong typing throughout
Easier debugging with centralized state tracking

Example (before/after):

// Before: Scattered instance properties
protected string $messageId = '';
protected bool $streamStarted = false;
protected string $currentText = '';

$this->messageId = EventID::generate();
$this->streamStarted = true;
$this->currentText .= $delta;

// After: Unified state object with fluent API
protected StreamState $state;

$this->state
    ->withMessageId(EventID::generate())
    ->markStreamStarted()
    ->appendText($delta);

Full Changelog: v0.91.1...v0.92.0

prism-php/prism v0.92.0 on GitHub

What's Changed

⚠️ BREAKING CHANGES

1. Removed Chunk Class and ChunkType Enum

2. Exception Renamed

3. Stream Event Type Changes

Migration Guide

Basic Streaming

Handling Tool Calls

Detecting Stream Completion

Handling Thinking/Reasoning

New Features

1. Granular Stream Events

2. Streaming Adapters

Server-Sent Events (SSE)

Data Protocol (Vercel AI SDK compatible)

Laravel Broadcasting

3. onComplete Callback

4. StreamCollector Utility

5. Testing Improvements

Internal Improvements

Unified StreamState Architecture

prism-php/prism v0.92.0
on GitHub

1. Removed `Chunk` Class and `ChunkType` Enum