PocketFlow PHP

PocketFlow PHP: Minimalist LLM framework for PHP. Let Agents build Agents!

Language: PHP | License: MIT

PocketFlow PHP is the first PHP implementation of the minimalist LLM framework concept

• Lightweight: ~400 lines of PHP. Zero bloat, pure PHP elegance.

• Framework Agnostic: Works with any PHP project, not tied to specific frameworks.

• Graph-Based: Simple node and flow abstraction for complex LLM workflows.

• ReactPHP Ready: Optional async support for parallel processing.

Get started with PocketFlow PHP:

• Installation: composer require projectsaturnstudios/pocketflow-php
• Quick Start: Copy the source files into your PHP project
• Documentation: Examples in this README and source code
• LLM Integration: Bring your own LLM client (OpenAI SDK, Guzzle, etc.)

Why PocketFlow PHP?

The PHP ecosystem was missing a minimalist LLM workflow framework... until now!

	Abstraction	PHP Integration	LLM Support	Lines	Dependencies
LLPhant	Comprehensive	Framework agnostic (Symfony/Laravel compatible)	Multiple providers (OpenAI, Anthropic, Mistral, etc.)	~15K+	Heavy (many providers)
LangChain PHP	Agent, Chain	Basic (Work in progress)	Limited (OpenAI, llama.cpp)	~5K	Moderate
PocketFlow PHP	Graph	Framework Agnostic (Pure PHP, works anywhere)	Bring Your Own (Use any HTTP client)	~400	Minimal

How does PocketFlow PHP work?

The core abstraction: Graph-based workflow execution with simple nodes and flows.

Core Components:

1. BaseNode: Foundation class with prep(), exec(), post() lifecycle
2. Node: Extended with retry logic and fallback handling
3. Flow: Orchestrates node execution with action-based routing
4. BatchNode/BatchFlow: Process arrays of data through workflows
5. AsyncNode/AsyncFlow: ReactPHP-powered parallel execution (optional)

Key Features:

• Reference Passing: Proper &$shared parameter handling for state persistence
• Type Safety: Full PHP 8.1+ type declarations
• Error Handling: Comprehensive exception handling with fallbacks
• Memory Management: Configurable data retention

Examples

Basic Hello World

<?php
require 'vendor/autoload.php';

use ProjectSaturnStudios\PocketFlowPHP\{Node, Flow};

class HelloNode extends Node 
{
    public function exec(mixed $prep_res): mixed 
    {
        return "Hello, " . ($prep_res['name'] ?? 'World') . "!";
    }
}

class OutputNode extends Node 
{
    public function prep(mixed &$shared): mixed 
    {
        return $shared; // Pass through shared data
    }
    
    public function exec(mixed $prep_res): mixed 
    {
        echo $prep_res['greeting'] ?? 'No greeting found';
        return 'done';
    }
    
    public function post(mixed &$shared, mixed $prep_res, mixed $exec_res): mixed 
    {
        return $exec_res;
    }
}

// Create nodes
$helloNode = new HelloNode();
$outputNode = new OutputNode();

// Chain them
$helloNode->next($outputNode, 'success');

// Create flow and run
$flow = new Flow($helloNode);
$shared = ['name' => 'PocketFlow'];

$result = $flow->_run($shared);

LLM Integration Example

<?php
// Bring your own LLM client
use OpenAI\Client as OpenAIClient;

class LLMNode extends Node 
{
    public function __construct(private OpenAIClient $client) {}
    
    public function prep(mixed &$shared): mixed 
    {
        return ['prompt' => $shared['prompt'] ?? 'Say hello!'];
    }
    
    public function exec(mixed $prep_res): mixed 
    {
        $response = $this->client->chat()->create([
            'model' => 'gpt-3.5-turbo',
            'messages' => [
                ['role' => 'user', 'content' => $prep_res['prompt']]
            ]
        ]);
        
        return $response->choices[0]->message->content;
    }
    
    public function post(mixed &$shared, mixed $prep_res, mixed $exec_res): mixed 
    {
        $shared['llm_response'] = $exec_res;
        return 'success';
    }
}

// Usage
$client = OpenAI::client('your-api-key');
$llmNode = new LLMNode($client);
$outputNode = new OutputNode();

$llmNode->next($outputNode, 'success');
$flow = new Flow($llmNode);

$shared = ['prompt' => 'Write a haiku about PHP'];
$flow->_run($shared);

Self-Looping Chat Bot

<?php
class ChatNode extends Node 
{
    public function __construct(private $llmClient) {}
    
    public function prep(mixed &$shared): mixed 
    {
        // Get user input
        echo "You: ";
        $input = trim(fgets(STDIN));
        
        if ($input === 'exit') {
            return ['action' => 'exit'];
        }
        
        $shared['messages'][] = ['role' => 'user', 'content' => $input];
        return ['messages' => $shared['messages']];
    }
    
    public function exec(mixed $prep_res): mixed 
    {
        if ($prep_res['action'] === 'exit') {
            return 'exit';
        }
        
        // Call your LLM here
        $response = $this->llmClient->chat($prep_res['messages']);
        return $response;
    }
    
    public function post(mixed &$shared, mixed $prep_res, mixed $exec_res): mixed 
    {
        if ($exec_res === 'exit') {
            echo "Goodbye!\n";
            return 'exit';
        }
        
        echo "AI: $exec_res\n\n";
        $shared['messages'][] = ['role' => 'assistant', 'content' => $exec_res];
        
        return 'continue'; // Self-loop
    }
}

// Create self-looping chat
$chatNode = new ChatNode($yourLLMClient);
$chatNode->next($chatNode, 'continue'); // Self-loop!

$flow = new Flow($chatNode);
$shared = ['messages' => []];
$flow->_run($shared);

Advanced Patterns

Batch Processing

$batchNode = new BatchNode();
$batchNode->setItems(['item1', 'item2', 'item3']);
$batchFlow = new BatchFlow($batchNode);

Async Workflows (ReactPHP - Optional Dependency)

// composer require react/socket
use React\EventLoop\Loop;

$asyncNode = new AsyncNode();
$asyncFlow = new AsyncFlow($asyncNode);
// Parallel execution with promises

Conditional Routing

$nodeA->next($nodeB, 'success');
$nodeA->next($nodeC, 'error'); 
$nodeA->next($nodeD, 'retry');

Comparison with Original PocketFlow

Feature	Python PocketFlow	PHP PocketFlow	Notes
Core Abstraction	✅ Graph	✅ Graph	Same philosophy
Async Support	✅ asyncio	⚠️ ReactPHP (optional)	Different implementations
Framework Integration	❌ None	✅ Framework Agnostic	Works with any PHP project
LLM Providers	❌ Manual	❌ Bring Your Own	Both require manual integration
Type Safety	⚠️ Optional	✅ Full	PHP 8.1+ strict types
Lines of Code	100	~400	More features, still minimal

Installation & Setup

Requirements

• PHP 8.1+
• Composer

Installation

composer require projectsaturnstudios/pocketflow-php

Optional Dependencies

# For async support
composer require react/socket

# For LLM integration (examples)
composer require openai-php/client
composer require guzzlehttp/guzzle

Quick Setup

1. Install Package: composer require projectsaturnstudios/pocketflow-php
2. Create Nodes: Extend Node or BaseNode classes
3. Chain Workflows: Use $node->next($nextNode, 'action')
4. Run Flows: $flow = new Flow($startNode); $flow->_run($shared);

LLM Integration Notes

Important: PocketFlow PHP is framework-agnostic and does not include LLM provider integrations. You need to:

1. Choose Your LLM Client: OpenAI SDK, Guzzle HTTP, cURL, etc.
2. Implement in Nodes: Add LLM calls in your exec() methods
3. Handle Responses: Process LLM responses in your post() methods
4. Manage State: Use &$shared parameters for conversation history

This approach gives you complete control over your LLM integrations without vendor lock-in.

Vendor Dependencies

Dependencies:

• ReactPHP: Required only for async features (optional)
• PHP 8.1+: Required for type safety and modern features

No Lock-ins:

• ❌ No specific LLM provider
• ❌ No specific HTTP client
• ❌ No specific framework
• ❌ No specific database

Contributing

This is the world's first PHP implementation of PocketFlow! We welcome contributions:

• 🐛 Bug Reports: Found an issue? Let us know!
• 🚀 Feature Requests: Ideas for PHP-specific features?
• 📖 Documentation: Help improve our docs
• 🧪 Examples: Share your PocketFlow PHP workflows

Roadmap

• Core Framework: Basic node and flow implementation
• Async Support: ReactPHP integration
• Batch Processing: Array and parallel processing
• More Examples: Real-world workflow patterns
• Performance: Optimize for large-scale applications
• Testing: Comprehensive test suite
• Documentation: Full API documentation

License

MIT License - same as original PocketFlow

Acknowledgments

• Original PocketFlow: The-Pocket/PocketFlow - The inspiration and foundation
• ReactPHP: For async capabilities in PHP (optional dependency)
• PHP Community: For the amazing language ecosystem

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Built with ADHD by Project Saturn Studios