MCP PHP SDK is the official PHP framework for implementing Model Context Protocol servers and clients. Developed in collaboration between the PHP Foundation and Symfony, it provides attribute-based discovery to expose PHP methods as AI-callable tools and resources. Key capabilities include: - Attribute-driven MCP server development using `#[McpTool]` and `#[McpResource]` annotations - STDIO transport for local MCP client integration - Built-in calculator tools supporting addition, subtraction, multiplication, and division operations - JSON configuration resource management - Framework-agnostic architecture following Symfony coding standards and backward compatibility promises - Automatic discovery of MCP capabilities from PHP classes

MCP PHP SDK

The official PHP SDK for Model Context Protocol (MCP). It provides a framework-agnostic API for implementing MCP servers and clients in PHP.

This project represents a collaboration between the PHP Foundation and the Symfony project. It adopts development practices and standards from the Symfony project, including Coding Standards and the Backward Compatibility Promise.

Until the first major release, this SDK is considered experimental, please see the roadmap for planned next steps and features.

Installation

composer require mcp/sdk

Quick Start

This example demonstrates the most common usage pattern - a STDIO server using attribute discovery.

1. Define Your MCP Elements

Create a class with MCP capabilities using attributes:

 $a + $b,
            'subtract' => $a - $b,
            'multiply' => $a * $b,
            'divide' => $b != 0 ? $a / $b : 'Error: Division by zero',
            default => 'Error: Unknown operation'
        };
    }
    #[McpResource(
        uri: 'config://calculator/settings',
        name: 'calculator_config',
        mimeType: 'application/json'
    )]
    public function getSettings(): array
    {
        return ['precision' => 2, 'allow_negative' => true];
    }
}

2. Create the Server Script

Create your MCP server:

#!/usr/bin/env php
setServerInfo('Calculator Server', '1.0.0')
    ->setDiscovery(__DIR__, ['.'])
    ->build();
$transport = new StdioTransport();
$server->run($transport);

3. Configure Your MCP Client

Add to your client configuration (e.g., Claude Desktop's mcp.json):

{
    "mcpServers": {
        "php-calculator": {
            "command": "php",
            "args": ["/absolute/path/to/your/server.php"]
        }
    }
}

4. Test Your Server

# Test with MCP Inspector
npx @modelcontextprotocol/inspector php /path/to/server.php
Your AI assistant can now call:
- add: Add two integers
- calculate: Perform arithmetic operations
- Read config://calculator/settings resource

Key Features

Attribute-Based Discovery

Define MCP elements using PHP attributes with automatic discovery:

// Tool with automatic name and description from method
#[McpTool]
public function generateReport(): string { /* ... */ }
// Tool with custom name
#[McpTool(name: 'custom_name')]
public function myMethod(): string { /* ... */ }
// Resource with URI and metadata
#[McpResource(uri: 'config://app/settings', mimeType: 'application/json')]
public function getConfig(): array { /* ... */ }

Manual Registration

Register capabilities programmatically:

$server = Server::builder()
    ->addTool([MyClass::class, 'myMethod'], 'tool_name')
    ->addResource([MyClass::class, 'getData'], 'data://config')
    ->build();

Multiple Transport Options

STDIO Transport (Command-line integration):

$transport = new StdioTransport();
$server->run($transport);

HTTP Transport (Web-based communication):

$transport = new StreamableHttpTransport($request, $responseFactory, $streamFactory);
$response = $server->run($transport);
// Handle $response in your web application

Session Management

By default, the SDK uses in-memory sessions. You can configure different session stores:

```php use Mcp\Server\Session\FileSessionStore; use Mcp\Server\Session\InMemorySessionStore; use Mcp\Server\Session\Psr16SessionStore; use Symfony\Component\Cache\Psr16Cache; use Symfony\Component\Cache\Adapter\RedisAdapter;

// Use default in-memory sessions with custom TTL $server = Server::builder() ->setSession(ttl: 7200) // 2 hours ->build();

// Override with file-based storage $server = Server::builder() ->setSession(new FileSessionStore(__DIR__ . '/sessions')) ->build();

// Override with in-memory storage and custom TTL $server = Server::builder() ->setSess