MCP PHP SDK

Table of Contents

• Overview
• Installation
• Quickstart
• What is MCP?
• Core Concepts
  • Server
  • Resources
  • Tools
  • Prompts
• Running Your Server
  • stdio
  • HTTP with SSE
  • Testing and Debugging
• Examples
  • Echo Server
  • SQLite Explorer
• Advanced Usage
  • Low-Level Server
  • Writing MCP Clients
  • Server Capabilities

Overview

The Model Context Protocol allows applications to provide context for LLMs in a standardized way, separating the concerns of providing context from the actual LLM interaction. This PHP SDK implements the full MCP specification, making it easy to:

• Build MCP clients that can connect to any MCP server
• Create MCP servers that expose resources, prompts and tools
• Use standard transports like stdio and SSE
• Handle all MCP protocol messages and lifecycle events

Installation

composer require huangdijia/mcp-sdk-php

Quick Start

Let's create a simple MCP server that exposes a calculator tool and some data:

<?php

use ModelContextProtocol\SDK\Server\McpServer;
use ModelContextProtocol\SDK\Server\Transport\StdioServerTransport;
use ModelContextProtocol\SDK\Shared\ResourceTemplate;

// Create an MCP server
$server = new McpServer([
    'name' => 'Demo',
    'version' => '1.0.0'
]);

// Add an addition tool
$server->tool('add', function (array $params) {
    $a = $params['a'] ?? 0;
    $b = $params['b'] ?? 0;
    
    return [
        'content' => [
            ['type' => 'text', 'text' => (string)($a + $b)]
        ]
    ];
});

// 示例：添加更多计算工具
$server->tool('multiply', function (array $params) {
    $a = $params['a'] ?? 0;
    $b = $params['b'] ?? 0;
    
    return [
        'content' => [
            ['type' => 'text', 'text' => (string)($a * $b)]
        ]
    ];
}, '将两个数字相乘', [
    'a' => ['type' => 'number', 'description' => '第一个数字'],
    'b' => ['type' => 'number', 'description' => '第二个数字'],
]);

// 示例：添加文本处理工具
$server->tool('textProcess', function (array $params) {
    $text = $params['text'] ?? '';
    $operation = $params['operation'] ?? 'none';

    switch ($operation) {
        case 'uppercase':
            $result = strtoupper($text);
            break;
        case 'lowercase':
            $result = strtolower($text);
            break;
        case 'capitalize':
            $result = ucwords($text);
            break;
        case 'reverse':
            $result = strrev($text);
            break;
        default:
            $result = $text;
    }

    return [
        'content' => [
            ['type' => 'text', 'text' => $result],
        ],
    ];
}, '处理文本字符串', [
    'text' => ['type' => 'string', 'description' => '要处理的文本'],
    'operation' => [
        'type' => 'string',
        'description' => '要执行的操作',
        'enum' => ['uppercase', 'lowercase', 'capitalize', 'reverse', 'none'],
    ],
]);

// Add a dynamic greeting resource
$server->resource(
    'greeting',
    new ResourceTemplate('greeting://{name}', ['list' => null]),
    function (string $uri, array $params) {
        return [
            'contents' => [[
                'uri' => $uri,
                'text' => "Hello, {$params['name']}!"
            ]]
        ];
    }
);

// 示例：添加更多资源类型
$server->resource(
    'time',
    new ResourceTemplate('time://', ['list' => []]),
    function (string $uri, array $params) {
        $timezone = $params['timezone'] ?? 'Asia/Shanghai';
        $format = $params['format'] ?? 'Y-m-d H:i:s';

        try {
            $dateTime = new DateTime('now', new DateTimeZone($timezone));
            
            return [
                'contents' => [[
                    'uri' => $uri,
                    'text' => '当前时间: ' . $dateTime->format($format),
                ]],
            ];
        } catch (Exception $e) {
            return [
                'contents' => [[
                    'uri' => $uri,
                    'text' => '时间获取失败: ' . $e->getMessage(),
                ]],
            ];
        }
    }
);

// Start receiving messages on stdin and sending messages on stdout
$transport = new StdioServerTransport();
$server->connect($transport);

What is MCP?

The Model Context Protocol (MCP) lets you build servers that expose data and functionality to LLM applications in a secure, standardized way. Think of it like a web API, but specifically designed for LLM interactions. MCP servers can:

• Expose data through Resources (think of these sort of like GET endpoints; they are used to load information into the LLM's context)
• Provide functionality through Tools (sort of like POST endpoints; they are used to execute code or otherwise produce a side effect)
• Define interaction patterns through Prompts (reusable templates for LLM interactions)
• And more!

Available Tools

MCP PHP SDK提供了多种内置工具，可以在您的MCP服务器中使用：

1. 基础计算工具

   • add - 将两个数字相加
   • multiply - 将两个数字相乘

2. 文本处理工具

   • textProcess - 可执行各种文本操作，包括：
     • 转为大写 (uppercase)
     • 转为小写 (lowercase)
     • 首字母大写 (capitalize)
     • 文本反转 (reverse)

Available Resources

SDK支持多种资源类型，可以通过URI方案访问：

1. greeting - 个性化问候

   • URI模板：greeting://{name}
   • 示例：greeting://world → "Hello, world!"

2. time - 时间信息

   • URI模式：time://
   • 提供当前时间信息，支持时区和格式自定义

3. random - 随机数生成

   • URI模式：random://{min}/{max}
   • 示例：random://1/100 → 生成1到100之间的随机数

MCP Server Setting

{
    "servers": {
        "test-mcp": {
            "command": "php",
            "args": [
                "[your-path]/mcp-php/examples/stdio-server.php",
            ],
            "env": {}
        }
    }
}

Output:

2025-04-06 20:08:54.123 [info] 正在停止服务器 test-mcp
2025-04-06 20:08:54.136 [info] 连接状态: 已停止
2025-04-06 20:08:54.138 [info] 正在启动服务器 test-mcp
2025-04-06 20:08:54.139 [info] 连接状态: 正在启动
2025-04-06 20:08:54.139 [info] Starting server from LocalProcess extension host
2025-04-06 20:08:54.148 [info] 连接状态: 正在启动
2025-04-06 20:08:54.148 [info] 连接状态: 正在运行
2025-04-06 20:08:54.353 [warning] Failed to parse message: "正在启动 MCP 服务器...\n"
2025-04-06 20:08:54.353 [warning] Failed to parse message: "服务器 \"PHP Example Server\" v1.0.0 已初始化并准备接收请求\n"
2025-04-06 20:08:54.354 [warning] Failed to parse message: "启动时间: 2025-04-06 12:08:54\n"
2025-04-06 20:08:54.354 [warning] Failed to parse message: "------------------------------------------------------\n"
2025-04-06 20:08:54.379 [info] Discovered 3 tools